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Paveliuc G, Lawson Daku LM. Improving the Accuracy in the Prediction of Transition-Metal Spin-State Energetics Using a Robust Variation-Based Approach: Density Functional Theory, CASPT2 and MC-PDFT Applied to the Case Study of Tris-Diimine Fe(II) Complexes. J Phys Chem A 2024. [PMID: 39315737 DOI: 10.1021/acs.jpca.4c04148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Designing ligands for transition metal complexes with a specified low-spin, high-spin or spin-crossover behavior is challenging. A major advance was recently made by Phan et al. [J. Am. Chem. Soc. 2017, 139, 6437-6447] who showed that the spin state of a homoleptic tris-diimine Fe(II) complex can be predicted from the N-N distance in the free diimine. They could thus predict the change in magnetic behavior on passing from the complexes of 2,2'-bipyridine (bpy), 2,2'-biimidazole (bim) and 2,2'-bis-2-imidazoline (bimz) ligands to those obtained with the modified analogs 4,5-diazafluoren-9-one (dafo), 1,1'-(α,α'-o-xylyl)-2,2'-bisimidazole (xbim) and 2,3,5,6,8,9-hexahydrodiimidazo[1,2-a:2', 1'-c]pyrazine (etbimz), respectively. Theoretically, the challenge lies in the accurate determination of the HS-LS zero-point energy difference ΔEHL°. The issue can be circumvented by using a variation-based approach, wherein ΔEHL° is not directly evaluated but obtained from the estimate of its variation Δ(ΔEHL°) in series of related systems, which include one whose ΔEHL° is accurately known [Phys. Chem. Chem. Phys. 2013, 15, 3752-3763; J. Phys. Chem. A 2022, 126, 6221-6235]. In this study, density functional theory (DFT), second-order multireference perturbation theory in its CASPT2 formulation, multiconfigurational pair DFT (MC-PDFT) and its hybrid formulation (HMC-PDFT) have been applied to the determination of Δ(ΔEHL°) in the pairs of complexes ( [ F e ( b p y ) 3 ] 2 + , [ F e ( d a f o ) 3 ] 2 + ) , ( [ F e ( b i m ) 3 ] 2 + , [ F e ( x b i m ) 3 ] 2 + ) and ( [ F e ( b i m z ) 3 ] 2 + , [ F e ( e t b i m z ) 3 ] 2 + ) . In DFT, we used several semilocal functionals and their global hybrids, as well as their D2, D3, D3BJ and D4 dispersion-corrected forms; and in MC-PDFT, different translated and fully translated functionals. The results are consistent with one another and in very good agreement with experiments. They show small to vanishing dependence on key details of the methods used: namely, the exact-exchange contribution to global hybrids; the ionization potential-electron affinity shift and basis sets used in the CASPT2 calculations; and the active spaces employed for the CASSCF wave functions used in the MC-PDFT and HMC-PDFT calculations. Insights into the change in the spin-state energetics accompanying the ligand exchanges were gained through a complexation energy analysis. Using the accurate CCSD(T) estimate of the HS-LS adiabatic energy difference in [ F e ( N C H ) 6 ] 2 + [J. Chem. Theory Comput. 2012, 8, 4216-4231], the Δ(ΔEHL°)-approach has been applied to the determination of ΔEHL° in the diimine complexes. The CASPT2 and DFT-D2 methods only give results in agreement with experiments. This suggests for the other methods a limitation in their treatment of dispersion which prevents them from accurately describing the spin-state energetics change accompanying the passing from [ F e ( N C H ) 6 ] 2 + with the tetragonal arrangement of its nitrile ligands to the tris-diimine complexes with the trigonal packing of their bulkier ligands.
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Affiliation(s)
- Gheorghe Paveliuc
- Université de Genève, 30 Quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland
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Tiwari RK, Paul R, Rajaraman G. Investigating the influence of oriented external electric fields on modulating spin-transition temperatures in Fe(II) SCO complexes: a theoretical perspective. Dalton Trans 2024; 53:14623-14633. [PMID: 39162581 DOI: 10.1039/d4dt00808a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/21/2024]
Abstract
Spin-crossover complexes, valued for their bistability, are extensively studied due to their numerous potential applications. A primary challenge in this molecular class is to identify effective methods to adjust the spin-transition temperature, which frequently falls outside the desired temperature range. This typically necessitates intricate chemical design and synthesis or the use of stimuli such as light or pressure, each introducing its own set of challenges for integrating these molecules into end-user applications. In this work, we aim to address this challenge using an oriented external electric field (OEEF) as one stimulus to modulate the spin-transition temperatures. For this purpose, we have employed both periodic and non-periodic calculations on three well-characterised Fe(II) SCO complexes, namely [Fe(phen)2(NCS)2] (1, phen = 1,10-phenanthroline), [Fe(bt)2(NCS)2] (2, bt = 2,2'-bi-2-thiazoline) and [Fe(py)2phen(NCS)2] (3, py = pyridine) possessing a similar structural motif of {FeN4N'2}. To begin with, DFT calculations employing the TPSSh functional were performed on complexes 1 to 3, and the estimated low-spin (LS) and high-spin (HS) gaps are 24.6, 15.3 and 15.4 kJ mol-1, and these are in the range expected for Fe(II) SCO complexes. In the next step, an OEEF was applied in the molecule along the pseudo-C2 axis that bisects two coordinated -NCS groups. Application of an OEEF was found to increase the Fe-ligand bond length and found to affect the spin-transition at the particular applied OEEF. While the HS state of 1 becomes the ground state at an applied field of 0.514 V Å-1, the LS state lies at a higher energy of 1.3 kJ mol-1. Similarly, complexes 2 and 3 also show the HS ground state at an applied field of 0.514 V Å-1, where the LS state stays at higher energies of 6.13 and 11.62 kJ mol-1, respectively. It is found that the overall change in enthalpy (ΔHHL) and entropy (ΔSHL) for the spin transition in the presence of OEEFs decreases upon increasing the strength of the applied field. The computed spin-transition temperature (T1/2) using DFT was found to be in close agreement with the experimentally reported values. It is estimated that on increasing the strength of the applied electric field, the T1/2 increases significantly. While the DFT computed T1/2 values for the optimised geometry of 1, 2 and 3 were found to be 134.6 K, 159.9 K and 111.4 K respectively, at the applied field of 0.6425 V Å-1T1/2 increases up to 187.3 K, 211.0 K and 184.4 K respectively, unveiling an hitherto unknown strategy to tune the T1/2 values. A limited benchmarking was performed with five additional exchange-correlation functionals: PBE, BLYP, B3LYP*, B3LYP, and PBE0. These functionals were found to be unsuitable for predicting the correct SCO behaviour for complex 2, and their behaviour under various electric fields did not improve. This emphasises the importance of choosing the correct functional at zero OEEF prior to testing them under various electric fields. Furthermore, calculations were performed with complex 1 adsorbed on the Au(111) surface. The formation of an Au-S bond during adsorption significantly stabilises the low-spin (LS) state, hindering the observation of spin-crossover (SCO) behaviour. Nonetheless, the application of an OEEF reduces this gap and brings the T1/2 value closer to the desired temperature. This offers a novel post-fabrication strategy for attaining SCO properties at the interface.
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Affiliation(s)
- Rupesh Kumar Tiwari
- Department of Chemistry, Indian Institute of Technology, Powai, Mumbai, India.
| | - Rajdeep Paul
- Department of Chemistry, Indian Institute of Technology, Powai, Mumbai, India.
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology, Powai, Mumbai, India.
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Gómez-Coca S, Ruiz E. Benchmarking Periodic Density Functional Theory Calculations for Spin-State Energies in Spin-Crossover Systems. Inorg Chem 2024; 63:13338-13345. [PMID: 38976861 PMCID: PMC11270997 DOI: 10.1021/acs.inorgchem.4c01094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 06/14/2024] [Accepted: 06/17/2024] [Indexed: 07/10/2024]
Abstract
Spin energetics is one of the biggest challenges associated with energy calculations for electronic structure methods. The energy differences of the spin states in spin-crossover compounds are very small, making them one of the most difficult systems to calculate. Few methods provide accurate results for calculating these energy differences. In addition, studies have usually focused on calculating energetics of single molecules, while spin-crossover properties are usually experimentally studied in the solid phase. In this paper, we have used periodic boundary conditions employing methods based on density functional theory to calculate the high- and low-spin energy differences for a test case of 20 extended systems. Compounds with different metals and ligands have been selected, and the results indicate that a semiquantitative description of the energy differences can be obtained with the combination of geometry optimization using the PBE functional including many-body dispersion approach and the use of meta-GGA functionals, such as r2SCAN but especially KTBM24, for the energy calculation. Other hybrid functionals, such as TPSSh, give generally good results, but the calculation of the exact exchange with periodic boundary conditions involves a huge increase in computer time and computational resources. It makes the proposed nonhybrid functional approach (KTBM24//PBE+MB) a great advantage for the study of periodic systems.
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Affiliation(s)
- Silvia Gómez-Coca
- Departament de Química
Inorgànica i Orgànica and Institut de Recerca de Química
Teòrica i Computacional, Universitat
de Barcelona, Barcelona 08028, Spain
| | - Eliseo Ruiz
- Departament de Química
Inorgànica i Orgànica and Institut de Recerca de Química
Teòrica i Computacional, Universitat
de Barcelona, Barcelona 08028, Spain
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Radoń M. Predicting spin states of iron porphyrins with DFT methods including crystal packing effects and thermodynamic corrections. Phys Chem Chem Phys 2024; 26:18182-18195. [PMID: 38899797 DOI: 10.1039/d4cp01327a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Accurate computational treatment of spin states for transition metal complexes, exemplified by iron porphyrins, lies at the heart of quantum bioinorganic chemistry, but at the same time represents a great challenge for approximate density functional theory (DFT) methods, which are predominantly used. Here, the accuracy of DFT methods for spin-state splittings in iron porphyrin is assessed by probing the ability to correctly predict the ground states for six FeIII or FeII complexes experimentally characterized in solid state. For each case, molecular and periodic DFT calculations are employed to quantify the effect of porphyrin side substituents and the crystal packing effect (CPE) on the spin-state splitting. It is proposed to partition the total CPE into additive components, the direct and structural one, the importance of which is shown to significantly vary from case to case. By knowing the substituent effect, the CPE, and the Gibbs free energy thermodynamic correction from calculations, one can employ the experimental ground-state information in order to derive a quantitative constraint on the electronic energy difference for a simplified (porphin) model of the experimentally characterized metalloporphyrin. The constraints derived in such a way-in the form of single or double inequalities-are used to assess the accuracy of dispersion-corrected DFT methods for 6 spin-state splittings of [FeIII(P)(2-MeIm)2]+, [FeIII(P)(2-MeIm)]+, [FeII(P)(THF)2] and [FeII(P)] models (where P is porphin, 2-MeIm is 2-methylimidazole, THF is tetrahydrofuran). These data constitute the new benchmark set of spin states for crystalline iron porphyrins (SSCIP6). The highest accuracy is obtained in the case of double-hybrid functionals (B2PLYP-D3, DSD-PBEB95-D3), whereas hybrid functionals, especially those with reduced admixture of the exact exchange (B3LYP*-D3, TPSSh-D3), are found to considerably overstabilize the intermediate spin state, leading to incorrect ground-state prediction in FeIII porphyrins. The present approach, which can be generalized to other transition metal complexes, is not only useful in method benchmarking, but also sheds light on the interpretations of experimental data for metalloporphyrins, which are important models to understand the electronic properties of heme proteins.
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Affiliation(s)
- Mariusz Radoń
- Faculty of Chemistry, Jagiellonian University, Kraków, Poland.
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Hehn L, Deglmann P, Kühn M. Chelate Complexes of 3d Transition Metal Ions─A Challenge for Electronic-Structure Methods? J Chem Theory Comput 2024; 20:4545-4568. [PMID: 38805381 DOI: 10.1021/acs.jctc.3c01375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Different electronic-structure methods were assessed for their ability to predict two important properties of the industrially relevant chelating agent nitrilotriacetic acid (NTA): its selectivity with respect to six different first-row transition metal ions and the spin-state energetics of its complex with Fe(III). The investigated methods encompassed density functional theory (DFT), the random phase approximation (RPA), coupled cluster (CC) theory, and the auxiliary-field quantum Monte Carlo (AFQMC) method, as well as the complete active space self-consistent field (CASSCF) method and the respective on-top methods: second-order N-electron valence state perturbation theory (NEVPT2) and multiconfiguration pair-density functional theory (MC-PDFT). Different strategies for selecting active spaces were explored, and the density matrix renormalization group (DMRG) approach was used to solve the largest active spaces. Despite somewhat ambiguous multi-reference diagnostics, most methods gave relatively good agreement with experimental data for the chemical reactions connected to the selectivity, which only involved transition-metal complexes in their high-spin state. CC methods yielded the highest accuracy followed by range-separated DFT and AFQMC. We discussed in detail that even higher accuracies can be obtained with NEVPT2, under the prerequisite that consistent active spaces along the entire chemical reaction can be selected, which was not the case for reactions involving Fe(III). A bigger challenge for electronic-structure methods was the prediction of the spin-state energetics, which additionally involved lower spin states that exhibited larger multi-reference diagnostics. Conceptually different, typically accurate methods ranging from CC theory via DMRG-NEVPT2 in combination with large active spaces to AFQMC agreed well that the high-spin state is energetically significantly favored over the other spin states. This was in contrast to most DFT functionals and RPA which yielded a smaller stabilization and some common DFT functionals and MC-PDFT even predicting the low-spin state to be energetically most favorable.
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Affiliation(s)
- Lukas Hehn
- Next Generation Computing, BASF SE, Pfalzgrafenstr. 1, 67061 Ludwigshafen, Germany
| | - Peter Deglmann
- Quantum Chemistry, BASF SE, Carl-Bosch-Str. 38, 67063 Ludwigshafen, Germany
| | - Michael Kühn
- Next Generation Computing, BASF SE, Pfalzgrafenstr. 1, 67061 Ludwigshafen, Germany
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Hao H, Li H, Jia T, Zhou Y, Zheng X. Fano resonance in molecular junctions of spin crossover complexes. Phys Chem Chem Phys 2024; 26:12652-12660. [PMID: 38597792 DOI: 10.1039/d3cp06178g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
In this paper, we introduce a novel molecular switch paradigm that integrates spin crossover complexes with the Fano resonance effect. Specifically, by performing density-functional theory calculations, the feasibility of achieving Fano resonance using spin crossover complexes is demonstrated in our designed molecular junctions using the complex {Fe[H2B(pz)2]2[Bp(bipy)]} [pz = 1-pyrazolyl, Bp(bipy) = bis(phenylethynyl)(2,2'-bipyridine)]. It is further revealed that the Fano resonance, particularly the Fano dip, is most prominent in the junction with cobalt tips among all the schemes, together with the spin-filtering effect. Most importantly, this junction of cobalt tips is able to exhibit three distinct conductance states, which are controlled by the modulation of Fano resonance due to the spin-state transition of the complex and the applied gate voltage. Such a molecular switch paradigm holds potential for applications in logic gates, memory units, sensors, thermoelectrics, and beyond.
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Affiliation(s)
- Hua Hao
- School of Physics, Hangzhou Normal University, Hangzhou 311121, China.
| | - Honghao Li
- School of Physics, Hangzhou Normal University, Hangzhou 311121, China.
| | - Ting Jia
- School of Physics, Hangzhou Normal University, Hangzhou 311121, China.
| | - Yanhong Zhou
- College of Science, East China Jiao Tong University, Nanchang 330013, China
| | - Xiaohong Zheng
- College of Information Science and Technology, Nanjing Forestry University, Nanjing 210037, China.
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7
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Drabik G, Radoń M. Approaching the Complete Basis Set Limit for Spin-State Energetics of Mononuclear First-Row Transition Metal Complexes. J Chem Theory Comput 2024; 20:3199-3217. [PMID: 38574194 PMCID: PMC11044276 DOI: 10.1021/acs.jctc.4c00092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/19/2024] [Accepted: 03/20/2024] [Indexed: 04/06/2024]
Abstract
Convergence to the complete basis set (CBS) limit is analyzed for the problem of spin-state energetics in mononuclear first-row transition metal (TM) complexes by taking under scrutiny a benchmark set of 18 energy differences between spin states for 13 chemically diverse TM complexes. The performance of conventional CCSD(T) and explicitly correlated CCSD(T)-F12a/b calculations in approaching the CCSD(T)/CBS limits is systematically studied. An economic computational protocol is developed based on the CCSD-F12a approximation and (here proposed) modified scaling of the perturbative triples term (T#). This computational protocol recovers the relative spin-state energetics of the benchmark set in excellent agreement with the reference CCSD(T)/CBS limits (mean absolute deviation of 0.4, mean signed deviation of 0.2, and maximum deviation of 0.8 kcal/mol) and enables performing canonical CCSD(T) calculations for mononuclear TM complexes sized up to ca. 50 atoms, which is illustrated by application to heme-related metalloporphyrins. Furthermore, a good transferability of the basis set incompleteness error (BSIE) is demonstrated for spin-state energetics computed using CCSD(T) and other wave function methods (MP2, CASPT2, CASPT2/CC, NEVPT2, and MRCI + Q), which justifies efficient focal-point approximations and simplifies the construction of multimethod benchmark studies.
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Affiliation(s)
- Gabriela Drabik
- Jagiellonian
University, Doctoral School
of Exact and Natural Sciences, Łojasiewicza 11, 30-348 Kraków, Poland
- Jagiellonian
University, Faculty of Chemistry, Gronostajowa 2, 30-387, Kraków Poland
| | - Mariusz Radoń
- Jagiellonian
University, Faculty of Chemistry, Gronostajowa 2, 30-387, Kraków Poland
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Pérez-Bitrián A, Munárriz J, Krause KB, Schlögl J, Hoffmann KF, Sturm JS, Hadi AN, Teutloff C, Wiesner A, Limberg C, Riedel S. Questing for homoleptic mononuclear manganese complexes with monodentate O-donor ligands. Chem Sci 2024; 15:5564-5572. [PMID: 38638238 PMCID: PMC11023055 DOI: 10.1039/d4sc00543k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 02/26/2024] [Indexed: 04/20/2024] Open
Abstract
Compounds containing Mn-O bonds are of utmost importance in biological systems and catalytic processes. Nevertheless, mononuclear manganese complexes containing all O-donor ligands are still rare. Taking advantage of the low tendency of the pentafluoroorthotellurate ligand (teflate, OTeF5) to bridge metal centers, we have synthesized two homoleptic manganese complexes with monomeric structures and an all O-donor coordination sphere. The tetrahedrally distorted MnII anion, [Mn(OTeF5)4]2-, can be described as a high spin d5 complex (S = 5/2), as found experimentally (magnetic susceptibility measurements and EPR spectroscopy) and using theoretical calculations (DFT and CASSCF/NEVPT2). The high spin d4 electronic configuration (S = 2) of the MnIII anion, [Mn(OTeF5)5]2-, was also determined experimentally and theoretically, and a square pyramidal geometry was found to be the most stable one for this complex. Finally, the bonding situation in both complexes was investigated by means of the Interacting Quantum Atoms (IQA) methodology and compared to that of hypothetical mononuclear fluoromanganates. Within each pair of [MnXn]2- (n = 4, 5) species (X = OTeF5, F), the Mn-X interaction is found to be comparable, therefore proving that the similar electronic properties of the teflate and the fluoride are also responsible for the stabilization of these unique species.
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Affiliation(s)
- Alberto Pérez-Bitrián
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin Fabeckstraße 34/36 Berlin 14195 Germany
- Institut für Chemie, Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 Berlin 12489 Germany
| | - Julen Munárriz
- Departamento de Química Física and Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza Pedro Cerbuna 12 Zaragoza 50009 Spain
| | - Konstantin B Krause
- Institut für Chemie, Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 Berlin 12489 Germany
| | - Johanna Schlögl
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin Fabeckstraße 34/36 Berlin 14195 Germany
| | - Kurt F Hoffmann
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin Fabeckstraße 34/36 Berlin 14195 Germany
| | - Johanna S Sturm
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin Fabeckstraße 34/36 Berlin 14195 Germany
| | - Amiera N Hadi
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin Fabeckstraße 34/36 Berlin 14195 Germany
| | - Christian Teutloff
- Fachbereich Physik, Freie Universität Berlin Arnimallee 14 Berlin 14195 Germany
| | - Anja Wiesner
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin Fabeckstraße 34/36 Berlin 14195 Germany
| | - Christian Limberg
- Institut für Chemie, Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 Berlin 12489 Germany
| | - Sebastian Riedel
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin Fabeckstraße 34/36 Berlin 14195 Germany
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Deorukhkar N, Egger C, Guénée L, Besnard C, Piguet C. Detecting Fe(II) Spin-Crossover by Modulation of Appended Eu(III) Luminescence in a Single Molecule. J Am Chem Soc 2024; 146:308-318. [PMID: 37877700 DOI: 10.1021/jacs.3c09017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Multifunctionality in spin-crossover (SCO) devices is limited to macroscopic or nanoscopic materials because of the need for long-range effects for inducing favorable cooperativity, efficient energy migration processes, and detectable magnetization transfer. The difficult reproducibility, control, and rational design of doped materials offer some place to SCO processes, modulating the optical properties of neighboring luminescent probes in single molecules. We report here on the combination of a [FeN6] chromophore, the SCO temperature and absorption spectra of which have been tuned to induce unprecedented room-temperature modulation of Eu(III)-based line-like luminescence in the molecular triple-helical [EuFe(L2)3]5+ complex in solution.
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Affiliation(s)
- Neel Deorukhkar
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Charlotte Egger
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Laure Guénée
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet. CH-1211 Geneva 4, Switzerland
| | - Céline Besnard
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet. CH-1211 Geneva 4, Switzerland
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
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Radoń M. Benchmarks for transition metal spin-state energetics: why and how to employ experimental reference data? Phys Chem Chem Phys 2023; 25:30800-30820. [PMID: 37938035 DOI: 10.1039/d3cp03537a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Accurate prediction of energy differences between alternative spin states of transition metal complexes is essential in computational (bio)inorganic chemistry-for example, in characterization of spin crossover materials and in the theoretical modeling of open-shell reaction mechanisms-but it remains one of the most compelling problems for quantum chemistry methods. A part of this challenge is to obtain reliable reference data for benchmark studies, as even the highest-level applicable methods are known to give divergent results. This Perspective discusses two possible approaches to method benchmarking for spin-state energetics: using either theoretically computed or experiment-derived reference data. With the focus on the latter approach, an extensive general review is provided for the available experimental data of spin-state energetics and their interpretations in the context of benchmark studies, targeting the possibility of back-correcting the vibrational effects and the influence of solvents or crystalline environments. With a growing amount of experience, these effects can be now not only qualitatively understood, but also quantitatively modeled, providing the way to derive nearly chemically accurate estimates of the electronic spin-state gaps to be used as benchmarks and advancing our understanding of the phenomena related to spin states in condensed phases.
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Affiliation(s)
- Mariusz Radoń
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Krakow, Poland.
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11
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Hostaš J, Pérez-Becerra KO, Calaminici P, Barrios-Herrera L, Lourenço MP, Tchagang A, Salahub DR, Köster AM. How important is the amount of exact exchange for spin-state energy ordering in DFT? Case study of molybdenum carbide cluster, Mo4C2. J Chem Phys 2023; 159:184301. [PMID: 37947508 DOI: 10.1063/5.0169409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023] Open
Abstract
Since the form of the exact functional in density functional theory is unknown, we must rely on density functional approximations (DFAs). In the past, very promising results have been reported by combining semi-local DFAs with exact, i.e. Hartree-Fock, exchange. However, the spin-state energy ordering and the predictions of global minima structures are particularly sensitive to the choice of the hybrid functional and to the amount of exact exchange. This has been already qualitatively described for single conformations, reactions, and a limited number of conformations. Here, we have analyzed the mixing of exact exchange in exchange functionals for a set of several hundred isomers of the transition metal carbide, Mo4C2. The analysis of the calculated energies and charges using PBE0-type functional with varying amounts of exact exchange yields the following insights: (1) The sensitivity of spin-energy splitting is strongly correlated with the amount of exact exchange mixing. (2) Spin contamination is exacerbated when correlation is omitted from the exchange-correlation functional. (3) There is not one ideal value for the exact exchange mixing which can be used to parametrize or choose among the functionals. Calculated energies and electronic structures are influenced by exact exchange at a different magnitude within a given distribution; therefore, to extend the application range of hybrid functionals to the full periodic table the spin-energy splitting energies should be investigated.
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Affiliation(s)
- Jiří Hostaš
- Department of Chemistry, CMS - Centre for Molecular Simulation, IQST - Institute for Quantum Science and Technology, Quantum Alberta, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Kevin O Pérez-Becerra
- Departamento de Química, Cinvestav, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, CDMX C.P. 07360, Mexico
| | - Patrizia Calaminici
- Departamento de Química, Cinvestav, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, CDMX C.P. 07360, Mexico
| | - Lizandra Barrios-Herrera
- Department of Chemistry, CMS - Centre for Molecular Simulation, IQST - Institute for Quantum Science and Technology, Quantum Alberta, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Maicon Pierre Lourenço
- Departamento de Química e Física - Centro de Ciências Exatas, Naturais e da Saúde - CCENS - Universidade Federal do Espírito Santo, 29500-000 Alegre, Espírito Santo, Brazil
| | - Alain Tchagang
- Digital Technologies Research Centre, National Research Council of Canada, 1200 Montréal Road, Ottawa, Ontario K1A 0R6, Canada
| | - Dennis R Salahub
- Department of Chemistry, CMS - Centre for Molecular Simulation, IQST - Institute for Quantum Science and Technology, Quantum Alberta, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Andreas M Köster
- Departamento de Química, Cinvestav, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, CDMX C.P. 07360, Mexico
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12
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Kulmaczewski R, Halcrow MA. Iron(II) complexes of 2,6-bis(imidazo[1,2- a]pyridin-2-yl)pyridine and related ligands with annelated distal heterocyclic donors. Dalton Trans 2023; 52:14928-14940. [PMID: 37799008 DOI: 10.1039/d3dt02747c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Following a published synthesis of 2,6-bis(imidazo[1,2-a]pyridin-2-yl)pyridine (L1), treatment of α,α'-dibromo-2,6-diacetylpyridine with 2 equiv. 2-aminopyrimidine or 2-aminoquinoline in refluxing acetonitrile respectively gives 2,6-bis(imidazo[1,2-a]pyrimidin-2-yl)pyridine (L2) and 2,6-bis(imidazo[1,2-a]quinolin-2-yl)pyridine (L3). Solvated crystals of [Fe(L1)2][BF4]2 (1[BF4]2) and [Fe(L2)2][BF4]2 (2[BF4]2) are mostly high-spin, although one solvate of 1[BF4]2 undergoes thermal spin-crossover on cooling. The iron coordination geometry is consistently distorted in crystals of 2[BF4]2 which may reflect the influence of intramolecular, inter-ligand N⋯π interactions on the molecular conformation. Only 1 : 1 Fe : L3 complexes were observed in solution, or isolated in the solid state; a crystal structure of [FeBr(py)2L3]Br·0.5H2O (py = pyridine) is presented. A solvate crystal structure of high-spin [Fe(L4)2][BF4]2 (L4 = 2,6-di{quinolin-2-yl}pyridine; 4[BF4]2) is also described, which exhibits a highly distorted six-coordinate geometry with a helical ligand conformation. The iron(II) complexes are high-spin in solution at room temperature, but 1[BF4]2 and 2[BF4]2 undergo thermal spin-crossover equilibria on cooling. All the compounds exhibit a ligand-based emission in solution at room temperature. Gas phase DFT calculations mostly reproduce the spin state properties of the complexes, but show small anomalies attributed to intramolecular, inter-ligand dispersion interactions in the sterically crowded molecules.
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Affiliation(s)
- Rafal Kulmaczewski
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT.
| | - Malcolm A Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT.
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13
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Mariano AL, Fernández-Blanco A, Poloni R. Perspective from a Hubbard U-density corrected scheme towards a spin crossover-mediated change in gas affinity. J Chem Phys 2023; 159:154108. [PMID: 37855313 DOI: 10.1063/5.0157971] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 09/29/2023] [Indexed: 10/20/2023] Open
Abstract
By employing a recently proposed Hubbard U density-corrected scheme within density functional theory, we provide design principles towards the design of materials exhibiting a spin crossover-assisted gas release. Small molecular fragments are used as case study to identify two main mechanisms behind the change in binding energy upon spin transitions. The feasibility of the proposed mechanism in porous crystals is assessed by correlating the change in binding energy of CO2, CO, N2, and H2, upon spin crossover, with the adiabatic energy difference associated with the spin state change of the square-planar metal in Hofmann-type clathrates (M = Fe, Mn, Ni). A few promising cases are identified for the adsorption of intermediate ligand field strength molecules such as N2 and H2. The latter stands out as the most original result as the strong interaction in low spin, as expected from a Kubas mechanism, results in a large change in binding energy. This work provides a general perspective towards the engineering of open-metal site frameworks exhibiting local environments designed to have a spin crossover upon adsorption of specific gas molecules.
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Affiliation(s)
- A L Mariano
- SIMaP, Grenoble-INP, CNRS, University of Grenoble Alpes, 38042 Grenoble, France
| | - A Fernández-Blanco
- SIMaP, Grenoble-INP, CNRS, University of Grenoble Alpes, 38042 Grenoble, France
- Institut Laue Langevin, 71 Avenue des Martyrs, CS 20156-38042 Grenoble, France
| | - R Poloni
- SIMaP, Grenoble-INP, CNRS, University of Grenoble Alpes, 38042 Grenoble, France
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14
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Manukovsky N, Kamieniarz G, Kronik L. Spin state and magnetic coupling in polynuclear Ni(II) complexes from density functional theory: is there an optimal amount of Fock exchange? J Chem Phys 2023; 159:154103. [PMID: 37846951 DOI: 10.1063/5.0169105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 09/25/2023] [Indexed: 10/18/2023] Open
Abstract
Reliable prediction of the ground-state spin and magnetic coupling constants in transition-metal complexes is a well-known challenge for density functional theory (DFT). One popular strategy for addressing this long-standing issue involves the modification of the fraction of Fock exchange in a hybrid functional. Here we explore the viability of this approach using three polynuclear metal-organic complexes based on a Ni4O4 cubane motif, having different ground state spin values (S = 0, 2, 4) owing to the use of different ligands. We systematically search for an optimum fraction of Fock exchange, across various global, range-separated, and double hybrid functionals. We find that for all functionals tested, at best there only exists a very narrow range of Fock exchange fractions which results in a correct prediction of the ground-state spin for all three complexes. The useful range is functional dependent, but general trends can be identified. Typically, at least two similar systems must be used in order to determine both an upper and lower limit of the optimal range. This is likely owing to conflicting demands of minimizing delocalization errors, which typically requires a higher percentage of Fock exchange, and addressing static correlation, which typically requires a lower one. Furthermore, we find that within the optimal range of Fock exchange, the sign and relative magnitude of Ni-Ni magnetic coupling constants are reasonably well reproduced, but there is still room for quantitative improvement in the prediction. Thus, the prediction of spin state and magnetic coupling in polynuclear complexes remains an ongoing challenge for DFT.
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Affiliation(s)
- Nurit Manukovsky
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovoth 7610001, Israel
| | | | - Leeor Kronik
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovoth 7610001, Israel
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15
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Neugebauer H, Bädorf B, Ehlert S, Hansen A, Grimme S. High-throughput screening of spin states for transition metal complexes with spin-polarized extended tight-binding methods. J Comput Chem 2023; 44:2120-2129. [PMID: 37401535 DOI: 10.1002/jcc.27185] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 05/26/2023] [Accepted: 05/30/2023] [Indexed: 07/05/2023]
Abstract
The semiempirical GFNn-xTB ( n = 1 , 2 ) tight-binding methods are extended with a spin-dependent energy term (spin-polarization), enabling the fast and efficient screening of different spin states for transition metal complexes. While GFNn-xTB methods inherently can not differentiate properly between high-spin (HS) and low-spin (LS) states, this shortcoming is corrected with the presented methods termed spGFNn-xTB. The performance of spGFNn-xTB methods for spin state energy splittings is evaluated on a newly compiled benchmark set of 90 complexes (27 HS and 63 LS complexes) containing 3d, 4d, and 5d transition metals (termed TM90S) employing DFT references at the TPSSh-D4/def2-QZVPP level of theory. The challenging TM90S set contains complexes with charges between - 4 and +3, spin multiplicities between 1 and 6, and spin-splitting energies that range from - 47.8 to 146.6 kcal/mol with a mean average of 32.2 kcal/mol. On this set the (sp)GFNn-xTB methods, the PM6-D3H4 method, and the PM7 method are evaluated with spGFN1-xTB yielding the lowest MAD of 19.6 kcal/mol followed by spGFN2-xTB with 24.8 kcal/mol. While for the 4d and 5d subsets small or no improvements are observed with spin-polarization, large improvements are obtained for the 3d subset with spGFN1-xTB yielding the smallest MAD of 14.2 kcal/mol followed by spGFN2-xTB with 17.9 kcal/mol and PM6-D3H4 with 28.4 kcal/mol. The correct sign of the spin state splittings is obtained with spGFN2-xTB in 89% of all cases closely followed by spGFN1-xTB with 88%. On the full set, a pure semiempirical vertical spGFN2-xTB//GFN2-xTB-based workflow for screening purposes yields a slightly better MAD of 22.2 kcal/mol due to error compensation, while being qualitative correct for one additional case. In combination with their low computational cost (scanning spin states in seconds), the spGFNn-xTB methods represent robust tools for pre-screening steps of spin state calculations and high-throughput workflows.
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Affiliation(s)
- Hagen Neugebauer
- Mulliken Center for Theoretical Chemistry, University of Bonn, Bonn, Germany
| | - Benedikt Bädorf
- Mulliken Center for Theoretical Chemistry, University of Bonn, Bonn, Germany
| | | | - Andreas Hansen
- Mulliken Center for Theoretical Chemistry, University of Bonn, Bonn, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, University of Bonn, Bonn, Germany
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16
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Paschelke T, Trumpf E, Grantz D, Pankau M, Grocholski N, Näther C, Sönnichsen FD, McConnell AJ. Tuning the spin-crossover properties of FeII4L 6 cages via the interplay of coordination motif and linker modifications. Dalton Trans 2023; 52:12789-12795. [PMID: 37615965 DOI: 10.1039/d3dt01569f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
Despite the increasing number of spin-crossover FeII-based cages, the interplay between ligand modifications (e.g. coordination motif substituents and linker) is not well-understood in these multinuclear systems, limiting rational design. Here, we report a family of FeII4L6 spin-crossover cages based on 2,2'-pyridylbenzimidazoles where subtle ligand modifications lowered the spin crossover temperature in CD3CN by up to 186 K. Comparing pairs of cages, CH3 substituents on either the coordination motif or phenylene linker lowered the spin-crossover temperature by 48 K, 91 K or 186 K, attributed to electronic effects, steric effects and a combination of both, respectively. The understanding of the interplay between ligand modifications gained from this study could be harnessed on the path towards the improved rational design of spin-crossover cages.
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Affiliation(s)
- Tobias Paschelke
- Otto Diels Institute of Organic Chemistry, Kiel University, Otto-Hahn-Platz 4, Kiel 24098, Germany
| | - Eicke Trumpf
- Otto Diels Institute of Organic Chemistry, Kiel University, Otto-Hahn-Platz 4, Kiel 24098, Germany
| | - David Grantz
- Otto Diels Institute of Organic Chemistry, Kiel University, Otto-Hahn-Platz 4, Kiel 24098, Germany
| | - Malte Pankau
- Otto Diels Institute of Organic Chemistry, Kiel University, Otto-Hahn-Platz 4, Kiel 24098, Germany
| | - Niclas Grocholski
- Otto Diels Institute of Organic Chemistry, Kiel University, Otto-Hahn-Platz 4, Kiel 24098, Germany
| | - Christian Näther
- Institute of Inorganic Chemistry, Kiel University, Max-Eyth-Straße 2, Kiel 24118, Germany
| | - Frank D Sönnichsen
- Otto Diels Institute of Organic Chemistry, Kiel University, Otto-Hahn-Platz 4, Kiel 24098, Germany
| | - Anna J McConnell
- Otto Diels Institute of Organic Chemistry, Kiel University, Otto-Hahn-Platz 4, Kiel 24098, Germany
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17
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Sánchez-de-Armas R, Jaber El Lala I, Calzado CJ. How complex-surface interactions modulate the spin transition of Fe(II) SCO complexes supported on metallic surfaces? Phys Chem Chem Phys 2023; 25:21673-21683. [PMID: 37551593 DOI: 10.1039/d3cp02539j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
The deposition of a prototypical spin-crossover [Fe(phen)2(NCS)2] complex on Au(111), Cu(111) and Ag(111) surfaces has been investigated by means of periodic DFT+U calculations, with the aim of understanding how different metallic surfaces affect the spin state switching. Our results show that adsorption is metal- and spin-dependent, with different preferred adsorption sites for the different surfaces and spin states. For the three considered surfaces adsorption energies are larger in the LS state than in the HS one, which increases the transition enthalpy by 58.7 kJ mol-1 for Cu(111), 14.6 kJ mol-1 for Au(111) and 9.6 kJ mol-1 for Ag(111) with respect to the free molecule. There is a clear correlation between this effect and the extent of the complex-surface interaction, which can be established from adsorption energies, surface-complex distances and charge density difference plots as: Cu(111) > Au(111) > Ag(111). Therefore, a stronger interaction with the surface produces a larger energy difference between two spin states, making the spin transition less probable to occur. Finally, our calculations show that it would be possible to probe the spin-state of the deposited molecules from the STM images, in line with the recent experimental results.
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Affiliation(s)
- Rocío Sánchez-de-Armas
- Departamento de Química Física, Universidad de Sevilla, C. Prof. García González, s/n, 41012, Spain.
| | - Iman Jaber El Lala
- Departamento de Química Física, Universidad de Sevilla, C. Prof. García González, s/n, 41012, Spain.
| | - Carmen J Calzado
- Departamento de Química Física, Universidad de Sevilla, C. Prof. García González, s/n, 41012, Spain.
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18
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Kelly CT, Jordan R, Felton S, Müller‐Bunz H, Morgan GG. Spontaneous Chiral Resolution of a Mn III Spin-Crossover Complex with High Temperature 80 K Hysteresis. Chemistry 2023; 29:e202300275. [PMID: 37037023 PMCID: PMC10946779 DOI: 10.1002/chem.202300275] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 04/12/2023]
Abstract
Non-centrosymmetric spin-switchable systems are of interest for their prospective applications as magnetically active non-linear optical materials and in multiferroic devices. Chiral resolution of simple spin-crossover chelate complexes into the Δ and Λ forms offers a facile route to homochiral magnetic switches, which could be easily enantiomerically enriched. Here, we report the spontaneous resolution of a new hysteretic spin-crossover complex, [MnIII (sal2 323)]SCN ⋅ EtOH (1), into Δ and Λ forms, without the use of chiral reagents, where sal2 323 is a Schiff base resulting from condensation of 1,2-bis(3-aminopropylamino)ethane with 2-hydroxybenzaldehyde. The enantiopurity of the Δ and Λ isomers was confirmed by single crystal X-ray diffraction and circular dichroism. Quantum chemistry calculations were used to investigate the electronic structure. The opening of a wide 80 K thermal hysteresis window at high temperature highlights the potential for good magneto-optical function at ambient temperature for materials of this type.
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Affiliation(s)
- Conor T. Kelly
- School of ChemistryUniversity College DublinBelfield, Dublin 4Ireland
| | - Ross Jordan
- Centre for Quantum Materials and TechnologiesSchool of Mathematics and PhysicsQueen's University BelfastBelfastBT7 1NNUK
| | - Solveig Felton
- Centre for Quantum Materials and TechnologiesSchool of Mathematics and PhysicsQueen's University BelfastBelfastBT7 1NNUK
| | - Helge Müller‐Bunz
- School of ChemistryUniversity College DublinBelfield, Dublin 4Ireland
| | - Grace G. Morgan
- School of ChemistryUniversity College DublinBelfield, Dublin 4Ireland
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19
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Montenegro-Pohlhammer N, Kuppusamy SK, Cárdenas-Jirón G, Calzado CJ, Ruben M. Computational demonstration of isomer- and spin-state-dependent charge transport in molecular junctions composed of charge-neutral iron(II) spin-crossover complexes. Dalton Trans 2023; 52:1229-1240. [PMID: 36606462 DOI: 10.1039/d2dt02598a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Chemistry offers a multitude of opportunities towards harnessing functional molecular materials with application propensity. One emerging area of interest is molecular spintronics, in which charge and spin degrees of freedom have been used to achieve power-efficient device architectures. Herein, we show that, with the aid of state-of-the-art quantum chemical calculations on designer molecular junctions, the conductance and spin filtering capabilities are molecular structure-dependent. As inferred from the calculations, structural control over the transport can be achieved by changing the position of the thiomethyl (SMe) anchoring groups for Au(111) electrodes in a set of isomeric 2,2'-bipyridine-based metal coordinating ligand entities L1 and L2. The computational studies on heteroleptic iron(II) coordination complexes (1 and 2) composed of L1 and L2 reveal that switching the spin-state of the iron(II) centers, from the low-spin (LS) to high-spin (HS) state, by means of an external electric field stimulus, could, in theory, be performed. Such switching, known as spin-crossover (SCO), renders charge transport through single-molecule junctions of 1 and 2 spin-state-dependent, and the HS junctions are more conductive than the LS junctions for both complexes. Additionally, the LS and HS junctions based on complex 1 are more conductive than those featuring complex 2. Moreover, it is predicted that the spin filtering efficiency (SFE) of the HS junctions strongly depends on the bridging complex geometry, with 1 showing a voltage-dependent SFE, whereas 2 exhibits an SFE of practically 100% over all the studied voltage range. To be pragmatic towards applications, the ligands L1 and L2 and complex 1 have been successfully synthesized, and the spin-state switching propensity of 1 in the bulk state has been elucidated. The results shown in this study might lead to the synthesis and characterization of isomeric SCO complexes with tuneable spin-state switching and charge transport properties.
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Affiliation(s)
- Nicolás Montenegro-Pohlhammer
- Laboratory of Theoretical Chemistry, Faculty of Chemistry and Biology, University of Santiago de Chile (USACH), 9170022, Santiago, Chile.
- Departamento de Química Física. Universidad de Sevilla, c/Profesor García González, s/n., 41012 Sevilla, Spain
| | - Senthil Kumar Kuppusamy
- Institute of Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
| | - Gloria Cárdenas-Jirón
- Laboratory of Theoretical Chemistry, Faculty of Chemistry and Biology, University of Santiago de Chile (USACH), 9170022, Santiago, Chile.
| | - Carmen J Calzado
- Departamento de Química Física. Universidad de Sevilla, c/Profesor García González, s/n., 41012 Sevilla, Spain
| | - Mario Ruben
- Institute of Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Centre Européen de Sciences Quantiques (CESQ), Institut de Science et d'Ingénierie Supramoléculaire (ISIS), Université de Strasbourg, Strasbourg, France
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20
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Reimann M, Kaupp M. Spin-State Splittings in 3d Transition-Metal Complexes Revisited: Toward a Reliable Theory Benchmark. J Chem Theory Comput 2023; 19:97-108. [PMID: 36576816 DOI: 10.1021/acs.jctc.2c00925] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A new composite method for the calculation of spin-crossover energies in 3d transition-metal complexes based on multireference methods is presented. The method reduces to MRCISD+Q at the complete-basis-set (CBS) level for atomic ions, for which it gives excitation energies with a mean absolute error of only ca. 0.01 eV. For molecular complexes, the CASPT2+δMRCI composite approach corresponds to a CASPT2/CBS calculation augmented by a high-level MRCISD+Q-CASPT2 correction with a smaller ligand basis set. For a set of [Fe(He)6]n+ test complexes, the approach reproduces full MRCISD+Q/CBS results to within better than 0.04 eV, without depending on any arbitrary IPEA shifts. The high-quality CASPT2+δMRCI method has then been applied to a series of 3d transition-metal hexaqua complexes in aqueous solution, augmented by an elaborate 3D-RISM-SCF solvent treatment of the underlying structures. It provides unprecedented agreement with experiment for the lowest-lying vertical spin-flip excitation energies, except for the Fe3+ system. Closer examination of the latter case provides strong evidence that the observed lowest-energy excitation at 1.56 eV, which has been used frequently for evaluating quantum-chemical methods, does not arise from the iron(III) hexaqua complex in solution, but from its singly deprotonated counterpart, [Fe(H2O)5OH]2+.
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Affiliation(s)
- Marc Reimann
- Institut für Chemie, Theoretische Chemie/Quantenchemie, Technische Universität Berlin, Sekr. C7, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Martin Kaupp
- Institut für Chemie, Theoretische Chemie/Quantenchemie, Technische Universität Berlin, Sekr. C7, Straße des 17. Juni 135, D-10623 Berlin, Germany
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21
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Review of Fe-based spin crossover metal complexes in multiscale device architectures. Inorganica Chim Acta 2023. [DOI: 10.1016/j.ica.2022.121168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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22
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Albavera-Mata A, Trickey SB, Hennig RG. Mean Value Ensemble Hubbard- U Correction for Spin-Crossover Molecules. J Phys Chem Lett 2022; 13:12049-12054. [PMID: 36542415 DOI: 10.1021/acs.jpclett.2c03388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
High-throughput searches for spin-crossover molecules require Hubbard-U corrections to common density functional exchange-correlation (XC) approximations. However, the Ueff values obtained from linear response or based on previous studies overcorrect the spin-crossover energies. We demonstrate that employing a linearly mixed ensemble average spin state as the reference configuration for the linear response calculation of Ueff resolves this issue. Validation on a commonly used set of spin-crossover complexes shows that these ensemble Ueff values consistently are smaller than those calculated directly on a pure spin state, irrespective of whether that be low- or high-spin. Adiabatic crossover energies using this methodology for a generalized gradient approximation XC functional are closer to the expected target energy range than with conventional Ueff values. Based on the observation that the Ueff correction is similar for different complexes that share transition metals with the same oxidation state, we devise a set of recommended averaged Ueff values for high-throughput calculations.
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Affiliation(s)
- Angel Albavera-Mata
- Center for Molecular Magnetic Quantum Materials, Quantum Theory Project, University of Florida, Gainesville, Florida32611, United States
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida32611, United States
| | - S B Trickey
- Center for Molecular Magnetic Quantum Materials, Quantum Theory Project, University of Florida, Gainesville, Florida32611, United States
- Department of Physics and Department of Chemistry, University of Florida, Gainesville, Florida32611, United States
| | - Richard G Hennig
- Center for Molecular Magnetic Quantum Materials, Quantum Theory Project, University of Florida, Gainesville, Florida32611, United States
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida32611, United States
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23
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Reimann M, Kaupp M. Spin-State Splittings in 3d Transition-Metal Complexes Revisited: Benchmarking Approximate Methods for Adiabatic Spin-State Energy Differences in Fe(II) Complexes. J Chem Theory Comput 2022; 18:7442-7456. [PMID: 36417564 DOI: 10.1021/acs.jctc.2c00924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The CASPT2+δMRCI composite approach reported in a companion paper has been extended and used to provide high-quality reference data for a series of adiabatic spin gaps (defined as ΔE = Equintet - Esinglet) of [FeIIL6]2+ complexes (L = CNH, CO, NCH, NH3, H2O), either at nonrelativistic level or including scalar relativistic effects. These highly accurate data have been used to evaluate the performance of various more approximate methods. Coupled-cluster theory with singles, doubles, and perturbative triples, CCSD(T), is found to agree well with the new reference data for Werner-type complexes but exhibits larger underestimates by up to 70 kJ/mol for the π-acceptor ligands, due to appreciable static correlation in the low-spin states of these systems. Widely used domain-based local CCSD(T) calculations, DLPNO-CCSD(T), are shown to depend very sensitively on the cutoff values used to construct the localized domains, and standard values are not sufficient. A large number of density functional approximations have been evaluated against the new reference data. The B2PLYP double hybrid gives the smallest deviations, but several functionals from different rungs of the usual ladder hierarchy give mean absolute deviations below 20 kJ/mol. This includes the B97-D semilocal functional, the PBE0* global hybrid with 15% exact-exchange admixture, as well as the local hybrids LH07s-SVWN and LH07t-SVWN. Several further functionals achieve mean absolute errors below 30 kJ/mol (M06L-D4, SSB-D, B97-1-D4, LC-ωPBE-D4, LH12ct-SsirPW92-D4, LH12ct-SsifPW92-D4, LH14t-calPBE-D4, LHJ-HFcal-D4, and several further double hybrids) and thereby also still overall outperform CCSD(T) or uncorrected CASPT2. While exact-exchange admixture is a crucial factor in favoring high-spin states, the present evaluations confirm that other aspects can be important as well. A number of the better-performing functionals underestimate the spin gaps for the π-acceptor ligands but overestimate them for L = NH3, H2O. In contrast to a previous suggestion, non-self-consistent density functional theory (DFT) computations on top of Hartree-Fock orbitals are not a promising path to produce accurate spin gaps in such complexes.
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Affiliation(s)
- Marc Reimann
- Technische Universität Berlin, Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Martin Kaupp
- Technische Universität Berlin, Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Straße des 17. Juni 135, D-10623 Berlin, Germany
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24
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Desrochers PJ, Abdulrahim A, Demaree KR, Fortner JA, Freeman JD, Provorse Long M, Martin ME, Gómez-García CJ, Gerasimchuk N. Rational Design of Iron Spin-Crossover Complexes Using Heteroscorpionate Chelates. Inorg Chem 2022; 61:18907-18922. [DOI: 10.1021/acs.inorgchem.2c02856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Patrick J. Desrochers
- Department of Chemistry and Biochemistry, University of Central Arkansas, Conway, Arkansas72035, United States
| | - Ali Abdulrahim
- Department of Chemistry and Biochemistry, University of Central Arkansas, Conway, Arkansas72035, United States
| | - Katherine R. Demaree
- Department of Chemistry and Biochemistry, University of Central Arkansas, Conway, Arkansas72035, United States
| | - Joseph A. Fortner
- Department of Chemistry and Biochemistry, University of Central Arkansas, Conway, Arkansas72035, United States
| | - Jamie D. Freeman
- Department of Chemistry and Biochemistry, University of Central Arkansas, Conway, Arkansas72035, United States
| | - Makenzie Provorse Long
- Department of Chemistry and Biochemistry, University of Central Arkansas, Conway, Arkansas72035, United States
| | - Madison E. Martin
- Department of Chemistry and Biochemistry, University of Central Arkansas, Conway, Arkansas72035, United States
| | - Carlos J. Gómez-García
- Departamento de Química Inorgánica, Universidad de Valencia, C/Dr. Moliner, 50. 46100Burjassot, Valencia, Spain
| | - Nikolay Gerasimchuk
- Department of Chemistry, Temple Hall 456, Missouri State University, Springfield, Missouri65897, United States
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25
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Kelly CT, Griffin M, Esien K, Felton S, Müller-Bunz H, Morgan GG. Crystallographic Detection of the Spin State in Fe III Complexes. CRYSTAL GROWTH & DESIGN 2022; 22:6429-6439. [PMID: 36345384 PMCID: PMC9634697 DOI: 10.1021/acs.cgd.2c00468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 08/22/2022] [Indexed: 06/16/2023]
Abstract
We report a single example of thermal spin crossover in a series of FeIII complexes, [FeIII(R-sal2323)]+, which typically stabilize the low-spin (S = 1/2) state. Single-crystal X-ray diffraction analysis of 53 such complexes with varying "R" groups, charge-balancing anions, and/or lattice solvation confirms bond lengths in line with an S = 1/2 ground state, with only the [FeIII(4-OMe-sal2323)]NO3 complex (1a) exhibiting longer bond lengths associated with a percentage of the spin sextet form at room temperature. Structural distortion parameters are investigated for the series. A magnetic susceptibility measurement of 1a reveals a gradual, incomplete transition, with T 1/2 = 265 K in the solid state, while Evans method NMR reveals that the sample persists in the low-spin form in solution at room temperature. Computational analysis of the spin state preferences for the cations [FeIII(4-OMe-sal2323)]+ and [FeIII(sal2323)]+ confirmed the energetic preference for the spin doublet form in both, and the thermal spin crossover in complex 1a is therefore attributed to perturbation of the crystal packing on warming.
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Affiliation(s)
- Conor T. Kelly
- School
of Chemistry, University College Dublin, Belfield, Dublin 4D04 N2E5, Ireland
| | - Michael Griffin
- School
of Chemistry, University College Dublin, Belfield, Dublin 4D04 N2E5, Ireland
| | - Kane Esien
- School
of Mathematics and Physics, Queen’s
University Belfast, BelfastBT7 1NN, United Kingdom
| | - Solveig Felton
- School
of Mathematics and Physics, Queen’s
University Belfast, BelfastBT7 1NN, United Kingdom
| | - Helge Müller-Bunz
- School
of Chemistry, University College Dublin, Belfield, Dublin 4D04 N2E5, Ireland
| | - Grace G. Morgan
- School
of Chemistry, University College Dublin, Belfield, Dublin 4D04 N2E5, Ireland
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26
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Dey B, Mehta S, Mondal A, Cirera J, Colacio E, Chandrasekhar V. Push and Pull Effect of Methoxy and Nitro Groups Modifies the Spin-State Switching Temperature in Fe(III) Complexes. ACS OMEGA 2022; 7:39268-39279. [PMID: 36340084 PMCID: PMC9631739 DOI: 10.1021/acsomega.2c05380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
We have explored the impact of electron-donating (methoxy) and electron-withdrawing (nitro) substituents on SalEen ligand based spin crossover (SCO) behavior of Fe(III) complexes. Thus, 3-X-substituted SalEen ligands were employed to prepare [Fe(3-X-SalEen)2]·NCSe, where X = OMe (1), H (2), and NO2 (3) (3-X-SalEen is the condensation product of 3-substituted salicylaldehyde and N-ethylethylenediamine). The characteristic spin transition temperature (T 1/2) is shown to shift to a lower temperature when an electron-donating substituent (OMe) is used and to a higher temperature when an electron-withdrawing substituent (NO2) is used. We used experimental and theoretical methods to determine the reasons for this behavior. The solid-state magnetic data revealed the transition temperatures for complexes 1, 2, and 3 to be 219, 251, and 366 K, respectively. The solution-state magnetic data also support this trend in T 1/2 values. UV-vis spectra analysis indicates that there is greater delocalization in the π-manifold of the ligand when the nitro group is the substituent. Theoretical studies through density functional theory methods suggest the methoxy substituent decreases the energy gap between the t2g and eg orbitals (explaining the lower T 1/2 value), while the nitro substituent increases the energy gap between the t2g and eg orbitals and thus increases the T 1/2 value.
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Affiliation(s)
- Bijoy Dey
- Tata
Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad500107, India
| | - Sakshi Mehta
- Solid
State and Structural Chemistry Unit, Indian
Institute of Science, Sir C V Raman Road, Bangalore, Karnataka560012, India
| | - Abhishake Mondal
- Solid
State and Structural Chemistry Unit, Indian
Institute of Science, Sir C V Raman Road, Bangalore, Karnataka560012, India
| | - Jordi Cirera
- Departament
de Química Inorgànica i Orgànica and Institut
de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028Barcelona, Spain
| | - Enrique Colacio
- Departamento
de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071Granada, Spain
| | - Vadapalli Chandrasekhar
- Tata
Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad500107, India
- Department
of Chemistry, Indian Institute of Technology
Kanpur, Kanpur, Uttar Pradesh208016, India
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27
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Hao G, Dale AS, N'Diaye AT, Chopdekar RV, Koch RJ, Jiang X, Mellinger C, Zhang J, Cheng R, Xu X, Dowben PA. Intermolecular interaction and cooperativity in an Fe(II) spin crossover molecular thin film system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:295201. [PMID: 35508146 DOI: 10.1088/1361-648x/ac6cbc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 05/04/2022] [Indexed: 06/14/2023]
Abstract
Compact domain features have been observed in spin crossover [Fe{H2B(pz)2}2(bipy)] molecular thin film systems via soft x-ray absorption spectroscopy and photoemission electron microscopy. The domains are in a mixed spin state that on average corresponds to roughly 2/3 the high spin occupation of the pure high spin state. Monte Carlo simulations support the presence of intermolecular interactions that can be described in terms of an Ising model in which interactions beyond nearest-neighbors cannot be neglected. This suggests the presence of short-range order to permit interactions between molecules beyond nearest neighbor that contribute to the formation of largely high spin state domains structure. The formation of a spin state domain structure appears to be the result of extensive cooperative effects.
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Affiliation(s)
- Guanhua Hao
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588, United States of America
- Advanced Light Source, Lawrence Berkeley National Lab, One Cyclotron Rd, Berkeley, CA 94720, United States of America
| | - Ashley S Dale
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States of America
| | - Alpha T N'Diaye
- Advanced Light Source, Lawrence Berkeley National Lab, One Cyclotron Rd, Berkeley, CA 94720, United States of America
| | - Rajesh V Chopdekar
- Advanced Light Source, Lawrence Berkeley National Lab, One Cyclotron Rd, Berkeley, CA 94720, United States of America
| | - Roland J Koch
- Advanced Light Source, Lawrence Berkeley National Lab, One Cyclotron Rd, Berkeley, CA 94720, United States of America
| | - Xuanyuan Jiang
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588, United States of America
| | - Corbyn Mellinger
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588, United States of America
| | - Jian Zhang
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, United States of America
| | - Ruihua Cheng
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States of America
| | - Xiaoshan Xu
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588, United States of America
| | - Peter A Dowben
- Department of Physics and Astronomy, Jorgensen Hall, University of Nebraska, Lincoln, NE 68588, United States of America
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28
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Drosou M, Mitsopoulou CA, Pantazis DA. Reconciling Local Coupled Cluster with Multireference Approaches for Transition Metal Spin-State Energetics. J Chem Theory Comput 2022; 18:3538-3548. [PMID: 35582788 PMCID: PMC9202354 DOI: 10.1021/acs.jctc.2c00265] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
![]()
Spin-state energetics
of transition metal complexes remain one
of the most challenging targets for electronic structure methods.
Among single-reference wave function approaches, local correlation
approximations to coupled cluster theory, most notably the domain-based
local pair natural orbital (DLPNO) approach, hold the promise of bringing
the accuracy of coupled cluster theory with single, double, and perturbative
triple excitations, CCSD(T), to molecular systems of realistic size
with acceptable computational cost. However, recent studies on spin-state
energetics of iron-containing systems raised doubts about the ability
of the DLPNO approach to adequately and systematically approximate
energetics obtained by the reference-quality complete active space
second-order perturbation theory with coupled-cluster semicore correlation,
CASPT2/CC. Here, we revisit this problem using a diverse set of iron
complexes and examine several aspects of the application of the DLPNO
approach. We show that DLPNO-CCSD(T) can accurately reproduce both
CASPT2/CC and canonical CCSD(T) results if two basic principles are
followed. These include the consistent use of the improved iterative
(T1) versus the semicanonical perturbative triple corrections
and, most importantly, a simple two-point extrapolation to the PNO
space limit. The latter practically eliminates errors arising from
the default truncation of electron-pair correlation spaces and should
be viewed as standard practice in applications of the method to transition
metal spin-state energetics. Our results show that reference-quality
results can be readily achieved with DLPNO-CCSD(T) if these principles
are followed. This is important also in view of the applicability
of the method to larger single-reference systems and multinuclear
clusters, whose treatment of dynamic correlation would be challenging
for multireference-based approaches.
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Affiliation(s)
- Maria Drosou
- Inorganic Chemistry Laboratory, National and Kapodistrian University of Athens, Panepistimiopolis, Zografou 15771, Greece
| | - Christiana A Mitsopoulou
- Inorganic Chemistry Laboratory, National and Kapodistrian University of Athens, Panepistimiopolis, Zografou 15771, Greece
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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29
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Affiliation(s)
- Milica Feldt
- Leibniz Institute for Catalysis: Leibniz-Institut fur Katalyse eV Theory & Catalysis Albert-Einstein-Str 29A 18059 Rostock GERMANY
| | - Quan Manh Phung
- Nagoya University: Nagoya Daigaku Department of Chemistry JAPAN
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30
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Finney BA, Chowdhury SR, Kirkvold C, Vlaisavljevich B. CASPT2 molecular geometries of Fe(II) spin-crossover complexes. Phys Chem Chem Phys 2022; 24:1390-1398. [PMID: 34981806 DOI: 10.1039/d1cp04885f] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Using fully internally contracted (FIC)-CASPT2 analytical gradients, geometry optimizations of spin-crossover complexes are reported. This approach is tested on a series of Fe(II) complexes with different sizes, ranging from 13 to 61 atoms. A combination of active space and basis set choices are employed to investigate their role in determining reliable molecular geometries. The reported strategy demonstrates that a wave function-based level of theory can be used to optimize the geometries of metal complexes in reasonable times and enables one to treat the molecular geometry and electronic structure of the complexes using the same level of theory. For a series of smaller Fe(II) SCO complexes, strong field ligands in the LS state result in geometries with the largest differences between DFT and CASPT2; however, good agreement overall is observed between DFT and CASPT2. For the larger complexes, moderate sized basis sets yield geometries that compare well with DFT and available experimental data. We recommend using the (10e,12o) active space since convergence to a minimum structure was more efficient than with truncated active spaces despite having similar Fe-ligand bond distances.
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Affiliation(s)
- Brian A Finney
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
| | - Sabyasachi Roy Chowdhury
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
| | - Clara Kirkvold
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
| | - Bess Vlaisavljevich
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
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31
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Sánchez-de-Armas R, Calzado CJ. Spin-crossover Fe(ii) complexes on a surface: a mixture of low-spin and high-spin molecules at low temperature from quantum-chemistry calculations. Inorg Chem Front 2022. [DOI: 10.1039/d1qi01487k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The deposition of a 2D monolayer of an Fe(ii) SCO complex on Au(111) is studied by quantum chemistry calculations. The results indicate that there exists thermodynamic and kinetic factors favoring the presence of the mixed HS/LS state at low temperature.
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Affiliation(s)
- Rocío Sánchez-de-Armas
- Departamento de Química Física, Universidad de Sevilla, calle Prof. García González, s/n, 41012 Sevilla, Spain
| | - Carmen J. Calzado
- Departamento de Química Física, Universidad de Sevilla, calle Prof. García González, s/n, 41012 Sevilla, Spain
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32
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Vidal D, Cirera J, Ribas-Arino J. Accurate calculation of spin-state energy gaps in Fe(III) spin-crossover systems using density functional methods. Dalton Trans 2021; 50:17635-17642. [PMID: 34806100 DOI: 10.1039/d1dt03335b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fe(III) complexes are receiving ever-increasing attention as spin crossover (SCO) systems because they are usually air stable, as opposed to Fe(II) complexes, which are prone to oxidation. Here, we present the first systematic study exclusively devoted to assess the accuracy of several exchange-correlation functionals when it comes to predicting the energy gap between the high-spin (S = 5/2) and the low-spin (S = 1/2) states of Fe(III) complexes. Using a dataset of 24 different Fe(III) hexacoordinated complexes, it is demonstrated that the B3LYP* functional is an excellent choice not only for predicting spin-state energy gaps for Fe(III) complexes undergoing spin-transitions but also for discriminating Fe(III) complexes that are either low- or high-spin in the whole range of temperatures. Our benchmark study has led to the identification of a very versatile Fe(III) compound whose SCO properties can be engineered upon changing a single axial ligand. Overall, this work demonstrates that B3LYP* is a reliable functional for screening new spin-crossover systems with tailored properties.
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Affiliation(s)
- Daniel Vidal
- Departament de Química Inorgànica i Orgànica and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain. .,Departament de Ciència de Materials i Química Física and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
| | - Jordi Cirera
- Departament de Química Inorgànica i Orgànica and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
| | - Jordi Ribas-Arino
- Departament de Ciència de Materials i Química Física and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
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33
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Sánchez-de-Armas R, Montenegro-Pohlhammer N, Develioglu A, Burzurí E, Calzado CJ. Spin-crossover complexes in nanoscale devices: main ingredients of the molecule-substrate interactions. NANOSCALE 2021; 13:18702-18713. [PMID: 34739026 DOI: 10.1039/d1nr04577f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Spin-crossover complexes embedded in nanodevices experience effects that are absent in the bulk that can modulate, quench and even suppress the spin-transition. In this work we explore, by means of state-of-the-art quantum chemistry calculations, different aspects of the integration of SCO molecules on active nanodevices, such as the geometry and energetics of the interaction with the substrate, extension of the charge transfer between the substrate and SCO molecule, impact of the applied external electric field on the spin-transition, and sensitivity of the transport properties on the local conditions of the substrate. We focus on the recently reported encapsulation of Fe(II) spin-crossover complexes in single-walled carbon nanotubes, with new measurements that support the theoretical findings. Even so our results could be useful to many other systems where SCO phenomena take place at the nanoscale, the spin-state switching is probed by an external electric field or current, or the substrate is responsible for the quenching of the SCO mechanism.
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Affiliation(s)
- Rocío Sánchez-de-Armas
- Departamento de Química Física. U. Sevilla, calle Prof. García González, s/n, 41012 Sevilla, Spain.
| | - Nicolás Montenegro-Pohlhammer
- Departamento de Química Física. U. Sevilla, calle Prof. García González, s/n, 41012 Sevilla, Spain.
- Laboratory of Theoretical Chemistry, Faculty of Chemistry and Biology, University of Santiago de Chile (USACH), 9170022, Santiago, Chile
| | - Aysegul Develioglu
- IMDEA Nanociencia, Campus de Cantoblanco, Calle Faraday 9, 28049 Madrid, Spain.
| | - Enrique Burzurí
- IMDEA Nanociencia, Campus de Cantoblanco, Calle Faraday 9, 28049 Madrid, Spain.
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Carmen J Calzado
- Departamento de Química Física. U. Sevilla, calle Prof. García González, s/n, 41012 Sevilla, Spain.
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34
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Spitsyna NG, Blagov MA, Lazarenko VA, Svetogorov RD, Zubavichus YV, Zorina LV, Maximova O, Yaroslavtsev SA, Rusakov VS, Raganyan GV, Yagubskii EB, Vasiliev AN. Peculiar Spin-Crossover Behavior in the 2D Polymer K[Fe III(5Cl-thsa) 2]. Inorg Chem 2021; 60:17462-17479. [PMID: 34757728 DOI: 10.1021/acs.inorgchem.1c01821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A potassium salt of the N2S2O2-coordination Fe(III) anion K[Fe(5Cl-thsa)2] (1) (5Cl-thsa - 5-chlorosalicylaldehyde thiosemicarbazone) is synthesized and characterized structurally and magnetically over a wide temperature range. Two polymorphs of salt 1 characterized by the common 2D polymer nature and assigned to the same orthorhombic Pbcn space group have been identified. The molecular structure of the minor polymorph of 1 was solved and refined at 100, 250, and 300 K is shown to correspond to the LS configuration. The dominant polymorph of 1 features K+ cations disordered over a few crystallographic sites, while the minor polymorph includes fully ordered K+ cations. The major polymorph exhibits a complete three-step cooperative spin-crossover transition both in the heating and cooling modes: The first step occurs in a temperature range from 2 to 50 K; the second abrupt hysteretic step occurs from 200 to 250 K with T1/2 = 230 K and a 6 K hysteresis loop. The third gradual step occurs from 250 to 440 K. According to 57Fe Mössbauer, XRPD, and EXAFS data, the spin-crossover transition for the dominant polymorph is quite peculiar. Indeed, the increase in the HS concentration by 57% at the second step does not result in the expected significant increase in the iron(III)-ligand bond lengths. In addition, the final step of the spin conversion (ΔγHS = 26%) is associated with a structural phase transition with a symmetry lowering from the orthorhombic (Pbcn) to the monoclinic (P21/n) space group. This nontrivial phenomenon was investigated in detail by applying magnetization measurements, electron spin resonance, 57Fe Mössbauer spectroscopy, and DFT calculations. These results provide a new platform for understanding the multistep spin-crossover character in the Fe(III) thsa-complexes and related compounds.
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Affiliation(s)
- Nataliya G Spitsyna
- Institute of Problems of Chemical Physics, RAS, Chernogolovka, 142432, Russia
| | - Maxim A Blagov
- Institute of Problems of Chemical Physics, RAS, Chernogolovka, 142432, Russia
| | | | | | - Yan V Zubavichus
- Synchrotron Radiation Facility SKIF, Boreskov Institute of Catalysis, SB RAS, Koltsovo 630559, Russia
| | | | - Olga Maximova
- Lomonosov Moscow State University, Moscow 119991, Russia
| | | | | | | | - Eduard B Yagubskii
- Institute of Problems of Chemical Physics, RAS, Chernogolovka, 142432, Russia
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35
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Zhang Y. Fe(phen) 2(NCS) 2 on Al(100): influence of AlN layer on spin crossover barrier. Phys Chem Chem Phys 2021; 23:23758-23767. [PMID: 34643204 DOI: 10.1039/d1cp03782j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We study how a nitride layer affects spin crossover (SCO) in a single Fe(phen)2(NCS)2 (Fephen) molecule adsorbed on the Al(100) surface using ab initio calculations. The Coulomb correlation of the open-shell 3d electrons has been considered using a Hubbard-U correction within different exchange-correlation approximations, including the van der Waals density functional. We determine the SCO energy barrier by computing the minimum energy path between the high-spin (HS) and low-spin (LS) states via direct constraint relaxations. It is shown that the HS-LS energy difference is slightly increased once deposited on Al(100), and thus LS states tend to be stabilized, as usually observed on metallic substrates. The oxidation of metallic Al to aluminum ions in the AlN layer promotes molecular adsorption, while it decreases HS-LS splitting, making Fephen switchable between its two spin states. Due to enhanced molecule-substrate bonding, the SCO barrier height is considerably increased, which may promote cooperativity. This effect is consistent with the AlN facilitated charge transfer at the interface that results from a reduction in surface work function. Our findings reveal the crucial role that surface electronic structure plays in maintaining spin bistability of the molecular adsorbate.
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Affiliation(s)
- Yachao Zhang
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Education University, Guiyang 550018, China.
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36
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Lerch M, Achazi AJ, Mollenhauer D, Becker J, Schindler S. A Mechanistic Study on the Reaction of Non‐Heme Diiron(III)‐Peroxido Complexes with Benzoyl Chloride. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Markus Lerch
- Institute of Inorganic and Analytical Chemistry Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Andreas J. Achazi
- Institute of Physical Chemistry Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Doreen Mollenhauer
- Institute of Physical Chemistry Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Jonathan Becker
- Institute of Inorganic and Analytical Chemistry Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Siegfried Schindler
- Institute of Inorganic and Analytical Chemistry Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Germany
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37
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Drosou M, Pantazis DA. Redox Isomerism in the S 3 State of the Oxygen-Evolving Complex Resolved by Coupled Cluster Theory. Chemistry 2021; 27:12815-12825. [PMID: 34288176 PMCID: PMC8518824 DOI: 10.1002/chem.202101567] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Indexed: 01/19/2023]
Abstract
The electronic and geometric structures of the water-oxidizing complex of photosystem II in the steps of the catalytic cycle that precede dioxygen evolution remain hotly debated. Recent structural and spectroscopic investigations support contradictory redox formulations for the active-site Mn4 CaOx cofactor in the final metastable S3 state. These range from the widely accepted MnIV 4 oxo-hydroxo model, which presumes that O-O bond formation occurs in the ultimate transient intermediate (S4 ) of the catalytic cycle, to a MnIII 2 MnIV 2 peroxo model representative of the contrasting "early-onset" O-O bond formation hypothesis. Density functional theory energetics of suggested S3 redox isomers are inconclusive because of extreme functional dependence. Here, we use the power of the domain-based local pair natural orbital approach to coupled cluster theory, DLPNO-CCSD(T), to present the first correlated wave function theory calculations of relative stabilities for distinct redox-isomeric forms of the S3 state. Our results enabled us to evaluate conflicting models for the S3 state of the oxygen-evolving complex (OEC) and to quantify the accuracy of lower-level theoretical approaches. Our assessment of the relevance of distinct redox-isomeric forms for the mechanism of biological water oxidation strongly disfavors the scenario of early-onset O-O formation advanced by literal interpretations of certain crystallographic models. This work serves as a case study in the application of modern coupled cluster implementations to redox isomerism problems in oligonuclear transition metal systems.
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Affiliation(s)
- Maria Drosou
- Inorganic Chemistry LaboratoryNational and Kapodistrian University of AthensPanepistimiopolisZografou15771Greece
| | - Dimitrios A. Pantazis
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an derRuhrGermany
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38
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Qiu YR, Cui L, Ge JY, Kurmoo M, Ma G, Su J. Iron(II) Spin Crossover Coordination Polymers Derived From a Redox Active Equatorial Tetrathiafulvalene Schiff-Base Ligand. Front Chem 2021; 9:692939. [PMID: 34409015 PMCID: PMC8365465 DOI: 10.3389/fchem.2021.692939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 07/19/2021] [Indexed: 11/13/2022] Open
Abstract
Two polymorphic FeII coordination polymers [FeIIL (TPPE)0.5] 1) and [(FeII3L3 (TPPE)1.5)] 2), were obtained from a redox-active tetrathiafulvalene (TTF) functionalized ligand [H2L = 2,2’-(((2-(4,5-bis-(methylthio)-1,3-dithiol-2-ylidene)benzo(d) (1,3) dithiole-5,6-diyl)bis-(azanediyl))bis-(meth anylylidene)) (2E,2E')-bis(3-oxobutanoate)] and a highly luminescent connector {TPPE = 1,1,2,2-tetrakis[4-(pyridine-4-yl)phenyl]-ethene}. Complex 1 has a layered structure where the TPPE uses its four diverging pyridines from the TPPE ligand are coordinated by the trans positions to the flat TTF Schiff-base ligand, and complex 2 has an unprecedented catenation of layers within two interpenetrated frameworks. These coordination polymers reserved the redox activity of the TTF unit. Complex 1 shows gradual spin transition behavior without hysteresis. And the fluorescence intensity of TPPE in 1 changes in tandem with the spin crossover (SCO) transition indicating a possible interplay between fluorescence and SCO behavior.
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Affiliation(s)
- Ya-Ru Qiu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China.,State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing, China
| | - Long Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing, China
| | - Jing-Yuan Ge
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
| | - Mohamedally Kurmoo
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing, China.,Institut de Chimie de Strasbourg, CNRS-UMR 7177 Université de Strasbourg, Strasbourg, France
| | - Guijun Ma
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jian Su
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing, China
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Vennelakanti V, Nandy A, Kulik HJ. The Effect of Hartree-Fock Exchange on Scaling Relations and Reaction Energetics for C–H Activation Catalysts. Top Catal 2021. [DOI: 10.1007/s11244-021-01482-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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40
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Crook MF, Laube C, Moreno-Hernandez IA, Kahnt A, Zahn S, Ondry JC, Liu A, Alivisatos AP. Elucidating the Role of Halides and Iron during Radiolysis-Driven Oxidative Etching of Gold Nanocrystals Using Liquid Cell Transmission Electron Microscopy and Pulse Radiolysis. J Am Chem Soc 2021; 143:11703-11713. [PMID: 34292703 DOI: 10.1021/jacs.1c05099] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Graphene liquid cell transmission electron microscopy (TEM) has enabled the observation of a variety of nanoscale transformations. Yet understanding the chemistry of the liquid cell solution and its impact on the observed transformations remains an important step toward translating insights from liquid cell TEM to benchtop chemistry. Gold nanocrystal etching can be used as a model system to probe the reactivity of the solution. FeCl3 has been widely used to promote gold oxidation in bulk and liquid cell TEM studies, but the roles of the halide and iron species have not been fully elucidated. In this work, we observed the etching trajectories of gold nanocrystals in different iron halide solutions. We observed an increase in gold nanocrystal etch rate going from Cl-- to Br-- to I--containing solutions. This is consistent with a mechanism in which the dominant role of halides is as complexation agents for oxidized gold species. Additionally, the mechanism through which FeCl3 induces etching in liquid cell TEM remains unclear. Ground-state bleaching of the Fe(III) absorption band observed through pulse radiolysis indicates that iron may react with Cl2·- radicals to form an oxidized transient species under irradiation. Complete active space self-consistent field (CASSCF) calculations indicate that the FeCl3 complex is oxidized to an Fe species with an OH radical ligand. Together our data indicate that an oxidized Fe species may be the active oxidant, while halides modulate the etch rate by tuning the reduction potential of gold nanocrystals.
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Affiliation(s)
- Michelle F Crook
- Department of Chemistry, University of California-Berkeley, Berkeley, California 94720, United States
| | - Christian Laube
- Department of Chemistry, University of California-Berkeley, Berkeley, California 94720, United States
| | - Ivan A Moreno-Hernandez
- Department of Chemistry, University of California-Berkeley, Berkeley, California 94720, United States
| | - Axel Kahnt
- Leibniz Institute of Surface Engineering (IOM), Permoserstr. 15, D-04318 Leipzig, Germany
| | - Stefan Zahn
- Leibniz Institute of Surface Engineering (IOM), Permoserstr. 15, D-04318 Leipzig, Germany
| | - Justin C Ondry
- Department of Chemistry, University of California-Berkeley, Berkeley, California 94720, United States.,Kavli Energy NanoScience Institute, University of California-Berkeley and Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Aijia Liu
- Department of Chemistry, University of California-Berkeley, Berkeley, California 94720, United States
| | - A Paul Alivisatos
- Department of Chemistry, University of California-Berkeley, Berkeley, California 94720, United States.,Kavli Energy NanoScience Institute, University of California-Berkeley and Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Department of Materials Science and Engineering, University of California-Berkeley, Berkeley, California 94720, United States
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41
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Melidis L, Styles IB, Hannon MJ. Targeting structural features of viral genomes with a nano-sized supramolecular drug. Chem Sci 2021; 12:7174-7184. [PMID: 34123344 PMCID: PMC8153246 DOI: 10.1039/d1sc00933h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/05/2021] [Indexed: 11/21/2022] Open
Abstract
RNA targeting is an exciting frontier for drug design. Intriguing targets include functional RNA structures in structurally-conserved untranslated regions (UTRs) of many lethal viruses. However, computational docking screens, valuable in protein structure targeting, fail for inherently flexible RNA. Herein we harness MD simulations with Markov state modeling to enable nanosize metallo-supramolecular cylinders to explore the dynamic RNA conformational landscape of HIV-1 TAR untranslated region RNA (representative for many viruses) replicating experimental observations. These cylinders are exciting as they have unprecedented nucleic acid binding and are the first supramolecular helicates shown to have anti-viral activity in cellulo: the approach developed in this study provides additional new insight about how such viral UTR structures might be targeted with the cylinder binding into the heart of an RNA-bulge cavity, how that reduces the conformational flexibility of the RNA and molecular details of the insertion mechanism. The approach and understanding developed represents a new roadmap for design of supramolecular drugs to target RNA structural motifs across biology and nucleic acid nanoscience.
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Affiliation(s)
- Lazaros Melidis
- Physical Sciences for Health Centre, University of Birmingham Edgbaston Birmingham B15 2TT UK
| | - Iain B Styles
- Physical Sciences for Health Centre, University of Birmingham Edgbaston Birmingham B15 2TT UK
- School of Computer Science, University of Birmingham Edgbaston Birmingham B15 2TT UK
- Centre of Membrane Proteins and Receptors, The Universities of Birmingham and Nottingham The Midlands UK
- Alan Turing Institute London UK
| | - Michael J Hannon
- Physical Sciences for Health Centre, University of Birmingham Edgbaston Birmingham B15 2TT UK
- School of Chemistry, University of Birmingham Edgbaston Birmingham B15 2TT UK
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42
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Starikov AG, Starikova AA, Minkin VI. Quantum Chemical Study of the Structures and Stability of Copper(II) Bis(diketonate) Dimers. RUSS J COORD CHEM+ 2021. [DOI: 10.1134/s1070328421030064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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43
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Castillo CE, Gamba I, Vicens L, Clémancey M, Latour JM, Costas M, Basallote MG. Spin State Tunes Oxygen Atom Transfer towards Fe IV O Formation in Fe II Complexes. Chemistry 2021; 27:4946-4954. [PMID: 33350013 DOI: 10.1002/chem.202004921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Indexed: 11/08/2022]
Abstract
Oxoiron(IV) complexes bearing tetradentate ligands have been extensively studied as models for the active oxidants in non-heme iron-dependent enzymes. These species are commonly generated by oxidation of their ferrous precursors. The mechanisms of these reactions have seldom been investigated. In this work, the reaction kinetics of complexes [FeII (CH3 CN)2 L](SbF6 )2 ([1](SbF6 )2 and [2](SbF6 )2 ) and [FeII (CF3 SO3 )2 L] ([1](OTf)2 and [2](OTf)2 (1, L=Me,H Pytacn; 2, L=nP,H Pytacn; R,R' Pytacn=1-[(6-R'-2-pyridyl)methyl]-4,7- di-R-1,4,7-triazacyclononane) with Bu4 NIO4 to form the corresponding [FeIV (O)(CH3 CN)L]2+ (3, L=Me,H Pytacn; 4, L=nP,H Pytacn) species was studied in acetonitrile/acetone at low temperatures. The reactions occur in a single kinetic step with activation parameters independent of the nature of the anion and similar to those obtained for the substitution reaction with Cl- as entering ligand, which indicates that formation of [FeIV (O)(CH3 CN)L]2+ is kinetically controlled by substitution in the starting complex to form [FeII (IO4 )(CH3 CN)L]+ intermediates that are converted rapidly to oxo complexes 3 and 4. The kinetics of the reaction is strongly dependent on the spin state of the starting complex. A detailed analysis of the magnetic susceptibility and kinetic data for the triflate complexes reveals that the experimental values of the activation parameters for both complexes are the result of partial compensation of the contributions from the thermodynamic parameters for the spin-crossover equilibrium and the activation parameters for substitution. The observation of these opposite and compensating effects by modifying the steric hindrance at the ligand illustrates so far unconsidered factors governing the mechanism of oxygen atom transfer leading to high-valent iron oxo species.
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Affiliation(s)
- Carmen E Castillo
- Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica, y Química Inorgánica, Facultad de Ciencias, Instituto de Biomoléculas (INBIO), Universidad de Cádiz, Puerto Real, Cádiz, 11510, Spain
| | - Ilaria Gamba
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, Campus de Montilivi, Girona, 17071, Catalonia, Spain
| | - Laia Vicens
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, Campus de Montilivi, Girona, 17071, Catalonia, Spain
| | - Martin Clémancey
- CEA, CNRS, IRIG, DIESE, LCBM, Université Grenoble Alpes, pmb, 38000, Grenoble, France
| | - Jean-Marc Latour
- CEA, CNRS, IRIG, DIESE, LCBM, Université Grenoble Alpes, pmb, 38000, Grenoble, France
| | - Miquel Costas
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, Campus de Montilivi, Girona, 17071, Catalonia, Spain
| | - Manuel G Basallote
- Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica, y Química Inorgánica, Facultad de Ciencias, Instituto de Biomoléculas (INBIO), Universidad de Cádiz, Puerto Real, Cádiz, 11510, Spain
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44
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Broclawik E, Kozyra P, Mitoraj M, Radoń M, Rejmak P. Zeolites at the Molecular Level: What Can Be Learned from Molecular Modeling. Molecules 2021; 26:molecules26061511. [PMID: 33801999 PMCID: PMC8001918 DOI: 10.3390/molecules26061511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 11/16/2022] Open
Abstract
This review puts the development of molecular modeling methods in the context of their applications to zeolitic active sites. We attempt to highlight the utmost necessity of close cooperation between theory and experiment, resulting both in advances in computational methods and in progress in experimental techniques.
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Affiliation(s)
- Ewa Broclawik
- Jerzy Haber Institute of Catalysis PAS, Niezapominajek 8, 30-239 Krakow, Poland
- Correspondence:
| | - Paweł Kozyra
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (P.K.); (M.M.); (M.R.)
| | - Mariusz Mitoraj
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (P.K.); (M.M.); (M.R.)
| | - Mariusz Radoń
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (P.K.); (M.M.); (M.R.)
| | - Paweł Rejmak
- Laboratory of X-ray and Electron Microscopy Research, Institute of Physics Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland;
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45
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Deorukhkar N, Besnard C, Guénée L, Piguet C. Tuning spin-crossover transition temperatures in non-symmetrical homoleptic meridional/facial [Fe(didentate) 3] 2+ complexes: what for and who cares about it? Dalton Trans 2021; 50:1206-1223. [PMID: 33404561 DOI: 10.1039/d0dt03828h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The [FeN6] chromophores found in [Fe(didentate)3]2+ complexes, where didentate is a non-symmetrical 2-(6-membered-heterocyclic ring)-benzimidazole ligand (Lk), exist as mixtures of two geometrical mer (C1-symmetry) and fac (C3-symmetry) isomers. Specific alkyl-substituted six-membered heterocyclic rings connected to the benzimidazole unit (pyridines in ligands L1-L3, pyrazines in L4-L5 and pyrimidines in L6-L7) control the ligand field strength and the electron delocalization so that [FeII(Lk)3]2+ display tunable thermally-induced spin transitions in solution. Thermodynamic, spectroscopic (UV-Vis, NMR) and magnetic studies in solution demonstrate that [Fe(L6)3]2+ (L6 = 1-methyl-2-(pyrimidin-2-yl)-1H-benzo[d]imidazole) exhibits a close to room temperature spin transition (T1/2 = 273(3) K) combined with a high stability formation constant ( in acetonitrile), which makes this complex suitable for the potential modulation of lanthanide-based luminescence in polymetallic helicates. A novel method is proposed for assigning specific thermodynamic spin crossover parameters to fac-[Fe(L6)3]2+ and mer-[Fe(L6)3]2+ isomers in solution. The observed difference relies mainly on the entropic content ΔS-ΔS = 11(1) J mol-1 K-1, which favors the spin transition for the meridional isomer. Intermolecular interactions occurring in the crystalline state largely overcome minor thermodynamic trends operating in diluted solutions and a single configurational isomer is usually observed in the solid state. Among the thirteen solved crystal structures 1-13 containing the [M(Lk)3]2+ cations (M = Fe, Ni, Zn, Lk = L6-L7), pure meridional isomers are observed six times, pure facial isomers also six times and a mixture (44% mer and 56% fac) is detected only once. Solid-state magnetic data recorded for the FeII complexes show the operation of slightly cooperative spin transitions in 7 (fac-[Fe(L6)3]2+) and 12 (mer-[Fe(L7)3]2+). For the meridional isomer in 6, a two-step spin state transition curve, associated with two phase transitions, is detected.
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Affiliation(s)
- Neel Deorukhkar
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
| | - Céline Besnard
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Laure Guénée
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
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46
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Palomino CM, Sánchez-de-Armas R, Calzado CJ. Theoretical inspection of the spin-crossover [Fe(tzpy) 2(NCS) 2] complex on Au(100) surface. J Chem Phys 2021; 154:034701. [PMID: 33499621 DOI: 10.1063/5.0036612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We explore the deposition of the spin-crossover [Fe(tzpy)2(NCS)2] complex on the Au(100) surface by means of density functional theory (DFT) based calculations. Two different routes have been employed: low-cost finite cluster-based calculations, where both the Fe complex and the surface are maintained fixed while the molecule approaches the surface; and periodic DFT plane-wave calculations, where the surface is represented by a four-layer slab and both the molecule and surface are relaxed. Our results show that the bridge adsorption site is preferred over the on-top and fourfold hollow ones for both spin states, although they are energetically close. The LS molecule is stabilized by the surface, and the HS-LS energy difference is enhanced by about 15%-25% once deposited. The different Fe ligand field for LS and HS molecules manifests on the composition and energy of the low-lying bands. Our simulated STM images indicate that it is possible to distinguish the spin state of the deposited molecules by tuning the bias voltage of the STM tip. Finally, it should be noted that the use of a reduced size cluster to simulate the Au(100) surface proves to be a low-cost and reliable strategy, providing results in good agreement with those resulting from state-of-the-art periodic calculations for this system.
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Affiliation(s)
- Carlos M Palomino
- Departamento de Química Física, c/Profesor García González, s/n 41012 Sevilla, Spain
| | | | - Carmen J Calzado
- Departamento de Química Física, c/Profesor García González, s/n 41012 Sevilla, Spain
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47
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Molecular S = 2 High-Spin, S = 0 Low-Spin and S = 0 ⇄ 2 Spin-Transition/-Crossover Nickel(II)-Bis(nitroxide) Coordination Compounds. INORGANICS 2021. [DOI: 10.3390/inorganics9020010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Heterospin systems have a great advantage in frontier orbital engineering since they utilize a wide diversity of paramagnetic chromophores and almost infinite combinations and mutual geometries. Strong exchange couplings are expected in 3d–2p heterospin compounds, where the nitroxide (aminoxyl) oxygen atom has a direct coordination bond with a nickel(II) ion. Complex formation of nickel(II) salts and tert-butyl 2-pyridyl nitroxides afforded a discrete 2p–3d–2p triad. Ferromagnetic coupling is favored when the magnetic orbitals, nickel(II) dσ and radical π*, are arranged in a strictly orthogonal fashion, namely, a planar coordination structure is characterized. In contrast, a severe twist around the coordination bond gives an orbital overlap, resulting in antiferromagnetic coupling. Non-chelatable nitroxide ligands are available for highly twisted and practically diamagnetic complexes. Here, the Ni–O–N–Csp2 torsion (dihedral) angle is supposed to be a useful metric to describe the nickel ion dislocated out of the radical π* nodal plane. Spin-transition complexes exhibited a planar coordination structure in a high-temperature phase and a nonplanar structure in a low-temperature phase. The gradual spin transition is described as a spin equilibrium obeying the van’t Hoff law. Density functional theory calculation indicates that the energy level crossing of the high- and low-spin states. The optimized structures of diamagnetic and high-spin states well agreed with the experimental large and small torsions, respectively. The novel mechanism of the present spin transition lies in the ferro-/antiferromagnetic coupling switch. The entropy-driven mechanism is plausible after combining the results of the related copper(II)-nitroxide compounds. Attention must be paid to the coupling parameter J as a variable of temperature in the magnetic analysis of such spin-transition materials. For future work, the exchange coupling may be tuned by chemical modification and external stimulus, because it has been clarified that the parameter is sensitive to the coordination structure and actually varies from 2J/kB = +400 K to −1400 K.
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48
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Drabik G, Szklarzewicz J, Radoń M. Spin-state energetics of metallocenes: How do best wave function and density functional theory results compare with the experimental data? Phys Chem Chem Phys 2021; 23:151-172. [PMID: 33313617 DOI: 10.1039/d0cp04727a] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We benchmark the accuracy of quantum-chemical methods, including wave function theory methods [coupled cluster theory at the CCSD(T) level, multiconfigurational perturbation-theory (CASPT2, NEVPT2) and internally contracted multireference configuration interaction (MRCI)] and 30 density functional theory (DFT) approximations, in reproducing the spin-state splittings of metallocenes. The reference values of the electronic energy differences are derived from the experimental spin-crossover enthalpy for manganocene and the spectral data of singlet-triplet transitions for ruthenocene, ferrocene, and cobaltocenium. For ferrocene and cobaltocenium we revise the previous experimental interpretations regarding the lowest triplet energy; our argument is based on the comparison with the lowest singlet excitation energy and herein reported, carefully determined absorption spectrum of ferrocene. When deriving vertical energies from the experimental band maxima, we go beyond the routine vertical energy approximation by introducing vibronic corrections based on simulated vibrational envelopes. The benchmarking result confirms the high accuracy of the CCSD(T) method (in particular, for UCCSD(T) based on Hartree-Fock orbitals we find for our dataset: maximum error 0.12 eV, weighted mean absolute error 0.07 eV, weighted mean signed error 0.01 eV). The high accuracy of the single-reference method is corroborated by the analysis of a multiconfigurational character of the complete active space wave function for the triplet state of ferrocene. On the DFT side, our results confirm the non-universality problem with approximate functionals. The present study is an important step toward establishing an extensive and representative benchmark set of experiment-derived spin-state energetics for transition metal complexes.
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Affiliation(s)
- Gabriela Drabik
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387 Kraków, Poland.
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49
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Dixon IM, Rat S, Sournia-Saquet A, Molnár G, Salmon L, Bousseksou A. On the Spin-State Dependence of Redox Potentials of Spin Crossover Complexes. Inorg Chem 2020; 59:18402-18406. [PMID: 33284611 DOI: 10.1021/acs.inorgchem.0c03043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Resistance switching properties of nanoscale junctions of spin crossover molecules have received recently much interest. In many cases, this property has been traced back to the variation of molecular orbital energies upon spin transition. However, one can also expect a substantial reorganization of the molecular structure due to charge localization, which calls for a better understanding of the relationship between the redox potential and the spin state of the molecule. To investigate this issue, we carried out a detailed density functional theory and variable temperature cyclic voltammetry investigation of the benchmark compound [Fe(HB(1,2,4-triazol-1-yl)3)2] in solution. We show that, for a correct thermodynamical picture, it is necessary to take into account the charge transfer-induced electronic and structural reorganization as well as spin equilibria in the oxidized and reduced species.
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Affiliation(s)
- Isabelle M Dixon
- Laboratoire de Chimie et Physique Quantiques, UMR 5626 CNRS/Université Toulouse 3-Paul Sabatier, Université de Toulouse, 118 route de Narbonne, 31062 Toulouse, France
| | - Sylvain Rat
- Laboratoire de Chimie de Coordination, UPR 8241, CNRS and Université de Toulouse, UPS, INP, 205 route de Narbonne, 31077 Toulouse, France
| | - Alix Sournia-Saquet
- Laboratoire de Chimie de Coordination, UPR 8241, CNRS and Université de Toulouse, UPS, INP, 205 route de Narbonne, 31077 Toulouse, France
| | - Gábor Molnár
- Laboratoire de Chimie de Coordination, UPR 8241, CNRS and Université de Toulouse, UPS, INP, 205 route de Narbonne, 31077 Toulouse, France
| | - Lionel Salmon
- Laboratoire de Chimie de Coordination, UPR 8241, CNRS and Université de Toulouse, UPS, INP, 205 route de Narbonne, 31077 Toulouse, France
| | - Azzedine Bousseksou
- Laboratoire de Chimie de Coordination, UPR 8241, CNRS and Université de Toulouse, UPS, INP, 205 route de Narbonne, 31077 Toulouse, France
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50
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Montenegro‐Pohlhammer N, Sánchez‐de‐Armas R, Calzado CJ. Deposition of the Spin Crossover Fe
II
–Pyrazolylborate Complex on Au(111) Surface at the Molecular Level. Chemistry 2020; 27:712-723. [DOI: 10.1002/chem.202003520] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/21/2020] [Indexed: 01/01/2023]
Affiliation(s)
| | - Rocío Sánchez‐de‐Armas
- Departamento de Química Física Universidad de Sevilla, c/ Profesor García González, s/n. 41012 Sevilla Spain
| | - Carmen J. Calzado
- Departamento de Química Física Universidad de Sevilla, c/ Profesor García González, s/n. 41012 Sevilla Spain
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