1
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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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2
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McFarlane NR, Gui J, Oláh J, Harvey JN. Gaseous inhibition of the transsulfuration pathway by cystathionine β-synthase. Phys Chem Chem Phys 2024; 26:16579-16588. [PMID: 38832404 DOI: 10.1039/d4cp01321b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The transsulfuration pathway plays a key role in mammals for maintaining the balance between cysteine and homocysteine, whose concentrations are critical in several biochemical processes. Human cystathionine β-synthase is a heme-containing, pyridoxal 5'-phosphate (PLP)-dependent enzyme found in this pathway. The heme group does not participate directly in catalysis, but has a regulatory function, whereby CO or NO binding inhibits the PLP-dependent reactions. In this study, we explore the detailed structural changes responsible for inhibition using quantum chemical calculations to validate the experimentally observed bonding patterns associated with heme CO and NO binding and molecular dynamics simulations to explore the medium-range structural changes triggered by gas binding and propagating to the PLP active site, which is more than 20 Å distant from the heme group. Our results support a previously proposed mechanical signaling model, whereby the cysteine decoordination associated with gas ligand binding leads to breaking of a hydrogen bond with an arginine residue on a neighbouring helix. In turn, this leads to a shift in position of the helix, and hence also of the PLP cofactor, ultimately disrupting a key hydrogen bond that stabilizes the PLP in its catalytically active form.
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Affiliation(s)
- Neil R McFarlane
- Department of Chemistry, KU Leuven, Celestijnenlaan 200f-box 2404, B-3001 Leuven, Belgium.
| | - Jiangli Gui
- Department of Chemistry, KU Leuven, Celestijnenlaan 200f-box 2404, B-3001 Leuven, Belgium.
| | - Julianna Oláh
- Department of Inorganic and Analytical Chemistry Budapest University of Technology and Economics H-1111 Budapest, Műegyeten rakpart 3, Hungary.
| | - Jeremy N Harvey
- Department of Chemistry, KU Leuven, Celestijnenlaan 200f-box 2404, B-3001 Leuven, Belgium.
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3
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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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4
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Greiner J, Gianni I, Nottoli T, Lipparini F, Eriksen JJ, Gauss J. MBE-CASSCF Approach for the Accurate Treatment of Large Active Spaces. J Chem Theory Comput 2024; 20:4663-4675. [PMID: 38809011 DOI: 10.1021/acs.jctc.4c00388] [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
We present a novel implementation of the complete active space self-consistent field (CASSCF) method that makes use of the many-body expanded full configuration interaction (MBE-FCI) method to incrementally approximate electronic structures within large active spaces. On the basis of a hybrid first-order algorithm employing both Super-CI and quasi-Newton strategies for the optimization of molecular orbitals, we demonstrate both computational efficacy and high accuracy of the resulting MBE-CASSCF method. We assess the performance of our implementation on a set of established numerical tests before applying MBE-CASSCF in the investigation of the triplet-quintet spin gap of iron(II) porphyrin with active spaces as large as 50 electrons in 50 orbitals.
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Affiliation(s)
- Jonas Greiner
- Department Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, Mainz 55128, Germany
| | - Ivan Gianni
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, Pisa 56124, Italy
| | - Tommaso Nottoli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, Pisa 56124, Italy
| | - Filippo Lipparini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, Pisa 56124, Italy
| | - Janus J Eriksen
- DTU Chemistry, Technical University of Denmark, Kemitorvet Bldg. 206, Kgs. Lyngby 2800, Denmark
| | - Jürgen Gauss
- Department Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, Mainz 55128, Germany
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5
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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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6
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Mukhopadhyaya A, Ali ME. Can Iron-Porphyrins Behave as Single-Molecule Magnets? J Phys Chem A 2024. [PMID: 38504619 DOI: 10.1021/acs.jpca.4c00430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
The study of magnetic properties, especially the magnetic anisotropy of iron-porphyrin complexes employing multiconfigurational methods, is quite challenging due to many strongly correlated electrons in nearly degenerate orbitals. However, a prerequisite for observing the magnetic anisotropy and slow magnetization relaxation, the zero-field splitting parameter, D, was experimentally observed decades ago for halide-based axially ligated penta-coordinate Fe(III)-porphyrins. In these complexes, the signs of D were reported mostly as positive; in a few cases, inconclusive signs of the D parameter were also mentioned. However, no ab initio calculations have been reported to shed light on this. Deciphering the electronic structure of these penta-coordinated complexes employing the complete active space self-consistent field method and N-electron valence second-order perturbation theory, we confirm the positive D values. However, a negative D value is highly desired to observe the single-molecule magnet properties without an external magnetic field, which we observed in the Fe(II)-porphyrin complexes with axial imidazole ligands instead of halide ligands. The detailed analysis of the multireference wave functions unravels the role of axial ligands in determining the sign and magnitude of the D parameters.
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Affiliation(s)
| | - Md Ehesan Ali
- Institute of Nano Science and Technology, Mohali, Punjab 140306, India
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7
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Ghosh A, Conradie J. Theoretical Photoelectron Spectroscopy of Quadruple-Bonded Dimolybdenum(II,II) and Ditungsten(II,II) Paddlewheel Complexes: Performance of Common Density Functional Theory Methods. ACS OMEGA 2024; 9:12237-12241. [PMID: 38496970 PMCID: PMC10938323 DOI: 10.1021/acsomega.4c00269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/13/2024] [Accepted: 02/22/2024] [Indexed: 03/19/2024]
Abstract
We have revisited the gas-phase photoelectron spectra of quadruple-bonded dimolybdenum(II,II) and ditungsten(II,II) paddlewheel complexes with modern density functional theory methods and obtained valuable calibration of four well-known exchange-correlation functionals, namely, BP86, OLYP, B3LYP*, and B3LYP. All four functionals were found to perform comparably, with discrepancies between calculated and experimental ionization potentials ranging from <0.1 to ∼0.5 eV, with the lowest errors observed for the classic pure functional BP86. All four functionals were found to reproduce differences in ionization potentials (IPs) between analogous Mo2 and W2 complexes, as well as large, experimentally observed ligand field effects on the IPs, with near-quantitative accuracy. The calculations help us interpret a number of differences between analogous Mo2 and W2 complexes through the lens of relativistic effects. Thus, relativity results in not only significantly lower IPs for the W2 complexes but also smaller HOMO-LUMO gaps and different triplet states relative to their Mo2 counterparts.
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Affiliation(s)
- Abhik Ghosh
- Department
of Chemistry, UiT − the Arctic University
of Norway, N-9037 Tromsø, Norway
| | - Jeanet Conradie
- Department
of Chemistry, UiT − the Arctic University
of Norway, N-9037 Tromsø, Norway
- Department
of Chemistry, University of the Free State, P.O. Box 339, Bloemfontein 9300, Republic
of South Africa
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8
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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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9
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Messias A, Pasquadibisceglie A, Alonso de Armiño D, De Simone G, Polticelli F, Coletta M, Ascenzi P, Estrin DA. Nitric oxide binding to ferrous nitrobindins: A computer simulation investigation. J Inorg Biochem 2023; 248:112336. [PMID: 37572543 DOI: 10.1016/j.jinorgbio.2023.112336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 06/28/2023] [Accepted: 07/19/2023] [Indexed: 08/14/2023]
Abstract
Nitrobindins (Nbs) represent an evolutionary conserved all-β-barrel heme-proteins displaying a highly solvent-exposed heme-Fe(III) atom, coordinated by a proximal His residue. Interestingly, even if the distal side is exposed to the solvent, the value of the second order rate constants for ligand binding to the ferrous derivative is almost one order of magnitude lower than those reported for myoglobins (Mbs). Noteworthy, nitric oxide binding to the sixth coordination position of the heme-Fe(II)-atom causes the cleavage or the severe weakening of the proximal His-Fe(II) bond. Here, we provide a computer simulation investigation to shed light on the molecular basis of ligand binding kinetics, by dissecting the ligand binding process into the ligand migration and the bond formation steps. Classical molecular dynamics simulations were performed employing a steered molecular dynamics approach and the Jarzinski equality to obtain ligand migration free energy profiles. The formation of the heme-Fe(II)-NO bond took into consideration the iron atom displacement from the heme plane. The ligand migration is almost unhindered, and the low rate constant for NO binding is due to the large displacement of the Fe(II) atom with respect to the heme plane responsible for the barrier for the Fe(II)-NO bond formation. In addition, we investigated the weakening and breaking of the proximal His-Fe(II) bond, observed experimentally upon NO binding, by means of a combination of classical molecular dynamics simulations and quantum-classical (QM-MM) optimizations. In both human and M. tuberculosis Nbs, a stable alternative conformation of the proximal His residue interacting with a network of water molecules was observed.
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Affiliation(s)
- Andresa Messias
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EHA Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Química-Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | | | - Diego Alonso de Armiño
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EHA Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Química-Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - Giovanna De Simone
- Department of Sciences, Roma Tre University, Viale G. Marconi 446, I-00146 Roma, Italy
| | - Fabio Polticelli
- Department of Sciences, Roma Tre University, Viale G. Marconi 446, I-00146 Roma, Italy
| | | | - Paolo Ascenzi
- Accademia Nazionale dei Lincei, Via della Lungara 10, 00165 Roma, Italy
| | - Darío A Estrin
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EHA Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Química-Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina.
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10
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Chamkin AA, Chamkina ES. A larger basis set describes atomization energy core-valence correction better than a higher-order coupled-cluster method. Phys Chem Chem Phys 2023; 25:27438-27447. [PMID: 37795799 DOI: 10.1039/d3cp03893a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
The accuracy of coupled-cluster methods for the computation of core-valence correction to atomization energy was assessed. Truncation levels up to CCSDTQP were considered together with (aug-)cc-pwCVnZ (n = D, T, Q, 5) basis sets and three different extrapolation techniques (canonical and flexible Helgaker formula and Riemann zeta function extrapolation). With the exception of CCSD, a more accurate correction can be obtained from a larger basis set using a lower-level coupled-cluster method, and not vice versa. For the CCSD(T) level, it also implies faster computations with modern codes. We also discussed the importance of moving to higher-order or all-electron methods for geometry optimizations. The present study provides the general knowledge needed for the most accurate state-of-the-art computations.
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Affiliation(s)
- Aleksandr A Chamkin
- A.N.Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences Russia, Vavilova St. 28, bld. 1, INEOS, 119334, Moscow, Russian Federation.
| | - Elena S Chamkina
- A.N.Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences Russia, Vavilova St. 28, bld. 1, INEOS, 119334, Moscow, Russian Federation.
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11
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Phung QM, Nam HN, Saitow M. Unraveling the Spin-State Energetics of FeN 4 Complexes with Ab Initio Methods. J Phys Chem A 2023; 127:7544-7556. [PMID: 37651105 DOI: 10.1021/acs.jpca.3c04254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
A systematic analysis was conducted to explore the spin-state energetics of a series of 19 FeN4 complexes. The performance of a large number of multireference methods was assessed, highlighting the significant challenges associated with accurately describing the spin-state energetics of FeN4 complexes. Most multireference methods were found to be susceptible to errors originating from the reference CASSCF wavefunction, leading to an overstabilization of high-spin states. Nonetheless, a few multireference methods, namely, CASPT2/CC, DSRG-MRPT3, and LDSRG(2), demonstrated promising performance compared to the benchmark CCSD(T) method. Furthermore, our study revealed that FeN4 complexes having a quintet ground state are exceedingly rare. Accordingly, only one specific model (Fe(L2)) and one synthesized complex (Fe(OTBP)) have the quintet ground state among the studied complexes. This scarcity of quintet FeN4 complexes highlights the unique nature of these systems and raises intriguing questions regarding the factors influencing spin states, such as the size of the macrocycle cavity, the introduction of substituents, or the induction of out-of-plane deformation.
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Affiliation(s)
- Quan Manh Phung
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Ho Ngoc Nam
- Institute of Materials Innovation, Institutes of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Masaaki Saitow
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
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12
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Zhang Y, Cao C, She Y, Yang YF, Houk KN. Molecular Dynamics of Iron Porphyrin-Catalyzed C-H Hydroxylation of Ethylbenzene. J Am Chem Soc 2023. [PMID: 37329571 DOI: 10.1021/jacs.3c03773] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Quasi-classical molecular dynamics (MD) simulations were carried out to study the mechanism of iron porphyrin-catalyzed hydroxylation of ethylbenzene. The hydrogen atom abstraction from ethylbenzene by iron-oxo species is the rate-determining step, which generates the radical pair of iron-hydroxo species and the benzylic radical. In the subsequent radical rebound step, the iron-hydroxo species and benzylic radical recombine to form the hydroxylated product, which is barrierless on the doublet energy surface. In the gas-phase quasi-classical MD study on the doublet energy surface, 45% of the reactive trajectories lead directly to the hydroxylated product, and this increases to 56% in implicit solvent model simulations. The percentage of reactive trajectories leading to the separated radical pair is 98-100% on high-spin (quartet/sextet) energy surfaces. The low-spin state reactivity dominates in the hydroxylation of ethylbenzene, which is dynamically both concerted and stepwise, since the time gap between C-H bond cleavage and C-O bond formation ranges from 41 to 619 fs. By contrast, the high-spin state catalysis is an energetically stepwise process, which has a negligible contribution to the formation of hydroxylation products.
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Affiliation(s)
- Yaling Zhang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China
| | - Chaoqin Cao
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China
| | - Yuanbin She
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China
| | - Yun-Fang Yang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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13
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Yang M, Chen X, Su X, She YB, Yang YF. Mechanistic Study of Chemoselectivity for Carbon Radical Hydroxylation versus Chlorination with Fe III (OH)(Cl) Complexes. Chem Asian J 2023; 18:e202201311. [PMID: 36705485 DOI: 10.1002/asia.202201311] [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: 12/31/2022] [Revised: 01/21/2023] [Accepted: 01/23/2023] [Indexed: 01/28/2023]
Abstract
The FeIII (OH)(Cl) complex resembles the key intermediate proposed for the non-heme iron halogenases. Goldberg and co-workers reported that the FeIII (OH)(Cl) RC reacts with triphenylmethyl radical 1 to give an exclusive hydroxylation product. To understand the chemoselectivity of the reaction of RC with 1, density functional theory (DFT) calculations have been conducted. From RC, the competing pathways were identified as the OH-transfer, Cl-transfer, and isomerization pathways. The direct Cl-transfer is more favorable than direct OH-transfer by 2.8 kcal/mol. The hydrogen bonding interactions between the hydroxyl group and the pendent amine ligand impede the direct OH-transfer from RC. Compared with the direct Cl-transfer pathway, the isomerization pathways require lower barriers. In isomer RCiso2 , the equatorial hydroxyl group, which has smaller diabatic bond dissociation energy, prefers to transfer to form the hydroxylation product. In FeIII (Cl)2 RC2 and RC2iso , the equatorial chloride group also prefers to transfer to give the chlorination product.
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Affiliation(s)
- Miao Yang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, P. R. China
| | - Xiahe Chen
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, P. R. China
| | - Xingxing Su
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, P. R. China
| | - Yuan-Bin She
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, P. R. China
| | - Yun-Fang Yang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, P. R. China
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14
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Shaya J, Aloum L, Lu CS, Corridon PR, Aoudi A, Shunnar A, Alefishat E, Petroianu G. Theoretical Study of Hydroxylation of α- and β-Pinene by a Cytochrome P450 Monooxygenase Model. Int J Mol Sci 2023; 24:ijms24065150. [PMID: 36982225 PMCID: PMC10048887 DOI: 10.3390/ijms24065150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 03/30/2023] Open
Abstract
Previous studies on biocatalytic transformations of pinenes by cytochrome P450 (CYP) enzymes reveal the formation of different oxygenated products from a single substrate due to the multistate reactivity of CYP and the many reactive sites in the pinene scaffold. Up until now, the detailed mechanism of these biocatalytic transformations of pinenes have not been reported. Hereby, we report a systematic theoretical study of the plausible hydrogen abstraction and hydroxylation reactions of α- and β-pinenes by CYP using the density functional theory (DFT) method. All DFT calculations in this study were based on B3LYP/LAN computational methodology using the Gaussian09 software. We used the B3LYP functional with corrections for dispersive forces, BSSE, and anharmonicity to study the mechanism and thermodynamic properties of these reactions using a bare model (without CYP) and a pinene-CYP model. According to the potential energy surface and Boltzmann distribution for radical conformers, the major reaction products of CYP-catalyzed hydrogen abstraction from β-pinene are the doublet trans (53.4%) and doublet cis (46.1%) radical conformer at delta site. The formation of doublet cis/trans hydroxylated products released a total Gibbs free energy of about 48 kcal/mol. As for alpha pinene, the most stable radicals were trans-doublet (86.4%) and cis-doublet (13.6%) at epsilon sites, and their hydroxylation products released a total of ~50 kcal/mol Gibbs free energy. Our results highlight the likely C-H abstraction and oxygen rebounding sites accounting for the multi-state of CYP (doublet, quartet, and sextet spin states) and the formation of different conformers due to the presence of cis/trans allylic hydrogen in α-pinene and β-pinene molecules.
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Affiliation(s)
- Janah Shaya
- Department of Chemistry, College of Arts and Sciences, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
| | - Lujain Aloum
- Department of Pharmacology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
| | - Chung-Shin Lu
- Department of General Education, National Taichung University of Science and Technology, Taichung 404, Taiwan, China
| | - Peter R Corridon
- Department of Immunology and Physiology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
- Biomedical Engineering and Healthcare Engineering Innovation Center, Khalifa University, Abu Dhabi 127788, United Arab Emirates
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
| | - Abdulrahman Aoudi
- Department of Chemistry, College of Arts and Sciences, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
| | - Abeer Shunnar
- Department of Chemistry, College of Arts and Sciences, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
| | - Eman Alefishat
- Department of Pharmacology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
- Department of Biopharmaceutics and Clinical Pharmacy, School of Pharmacy, The University of Jordan, Amman 11972, Jordan
| | - Georg Petroianu
- Department of Pharmacology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates
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15
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Lew-Yee JFH, Del Campo JM, Piris M. Electron Correlation in the Iron(II) Porphyrin by Natural Orbital Functional Approximations. J Chem Theory Comput 2023; 19:211-220. [PMID: 36579972 PMCID: PMC9996833 DOI: 10.1021/acs.jctc.2c01093] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The relative stability of the singlet, triplet, and quintet spin states of iron(II) porphyrin (FeP) represents a challenging problem for electronic structure methods. While it is currently accepted that the ground state is a triplet, multiconfigurational wave function-based methods predict a quintet, and density functional approximations vary between triplet and quintet states, leading to a prediction that highly depends on the features of the method employed. The recently proposed Global Natural Orbital Functional (GNOF) aims to provide a balanced treatment between static and dynamic correlation, and together with the previous Piris Natural Orbital Functionals (PNOFs), allowed us to explore the importance of each type of correlation in the stability order of the states of FeP with a method that conserves the spin of the system. It is noteworthy that GNOF correlates all electrons in all available orbitals for a given basis set; in the case of the FeP with a double-ζ basis set as used in this work, this means that GNOF can properly correlate 186 electrons in 465 orbitals, significantly increasing the sizes of systems amenable to multiconfigurational treatment. Results show that PNOF5, PNOF7s, and PNOF7 predict the quintet to have a lower energy than the triplet state; however, the addition of dynamic correlation via second-order Møller-Plesset corrections (NOF-MP2) turns the triplet state to be lower than the quintet state, a prediction also reproduced by GNOF that incorporates much more dynamic correlation than its predecessors.
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Affiliation(s)
- Juan Felipe Huan Lew-Yee
- Departamento de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México, México CityC.P. 04510, México
| | - Jorge M Del Campo
- Departamento de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México, México CityC.P. 04510, México
| | - Mario Piris
- Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU), P.K. 1072, 20080Donostia, Euskadi, Spain.,Donostia International Physics Center (DIPC), 20018Donostia, Euskadi, Spain.,IKERBASQUE, Basque Foundation for Science, 48013Bilbao, Euskadi, Spain
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16
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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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17
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Reliably assessing the electronic structure of cytochrome P450 on today's classical computers and tomorrow's quantum computers. Proc Natl Acad Sci U S A 2022; 119:e2203533119. [PMID: 36095200 PMCID: PMC9499570 DOI: 10.1073/pnas.2203533119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Chemical simulation is one of the most promising applications for future quantum computers. It is thought that quantum computers may enable accurate simulation for complex molecules that are otherwise impossible to simulate classically; that is, it displays quantum advantage. To better understand quantum advantage in chemical simulation, we explore what quantum and classical resources are required to simulate a series of pharmaceutically relevant molecules. Using classical methods, we show that reliable classical simulation of these molecules requires significant resources and therefore is a promising candidate for quantum simulation. We estimate the quantum resources, both in overall simulation time and the size. The insights from this study pave the way for future quantum simulation of complex molecules. An accurate assessment of how quantum computers can be used for chemical simulation, especially their potential computational advantages, provides important context on how to deploy these future devices. To perform this assessment reliably, quantum resource estimates must be coupled with classical computations attempting to answer relevant chemical questions and to define the classical algorithms simulation frontier. Herein, we explore the quantum computation and classical computation resources required to assess the electronic structure of cytochrome P450 enzymes (CYPs) and thus define a classical–quantum advantage boundary. This is accomplished by analyzing the convergence of density matrix renormalization group plus n-electron valence state perturbation theory (DMRG+NEVPT2) and coupled-cluster singles doubles with noniterative triples [CCSD(T)] calculations for spin gaps in models of the CYP catalytic cycle that indicate multireference character. The quantum resources required to perform phase estimation using qubitized quantum walks are calculated for the same systems. Compilation into the surface code provides runtime estimates to compare directly to DMRG runtimes and to evaluate potential quantum advantage. Both classical and quantum resource estimates suggest that simulation of CYP models at scales large enough to balance dynamic and multiconfigurational electron correlation has the potential to be a quantum advantage problem and emphasizes the important interplay between classical computations and quantum algorithms development for chemical simulation.
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18
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Missana A, Hauser A, Lawson Daku LM. Environmental Control of the Magnetic Behavior of Transition Metal Complexes: Density Functional Theory Study of Zeolite Y Embedded Complexes [M(bpy) 3] 2+@Y (M = Fe 2+, Co 2+). J Phys Chem A 2022; 126:6221-6235. [PMID: 36067495 DOI: 10.1021/acs.jpca.2c05070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using the supramolecular approach developed for the study of the guest-host interactions in the zeolite Y encapsulated [Fe(bpy)3]2+ compound: [Fe(bpy)3]2+@Y (bpy = 2,2'-bipyridine) [Vargas et al., J. Chem. Theory Comput. 2009, 5, 97-115], we apply density functional theory (DFT) to the study of the influence of zeolite Y encapsulation on the structural and energetic properties of [Co(bpy)3]2+ in the low-spin (LS) and high-spin (HS) states, while revisiting [Fe(bpy)3]2+@Y. Although the accurate prediction of the HS-LS energy difference ΔEHLel remains challenging for current DFT methods, they give accurate estimates of its variation Δ(ΔEHLel) in a series of complexes of a given transition metal ion. Therefore, denoting [M(bpy)3]2+@YSM as the supramolecular model of the inclusion compounds, the values of ΔEHLel for the bpy complexes in the gas phase and in the supercage of zeolite Y were determined by combining the DFT estimates of Δ(ΔEHLel) in the series {[M(NCH)6]2+, [M(bpy)3]2+, and [M(bpy)3]2+@YSM}, with accurate CCSD(T) estimates of ΔEHLel in the benchmark complexes [M(NCH)6]2+ (M = Fe, Co) [Lawson Daku et al., J. Chem. Theory Comput., 2012, 8, 4216-4231]. Generalized gradient approximations as well as global and range-separated hybrids were employed. In order to better account for the key role of dispersion, they were also augmented with the semiempirical D2, D3BJ, and D3BJM dispersion corrections when available. The use of the D3BJ and D3BJM corrections led to similar results, and this is only with the use of the D2 scheme that (i) the free and encapsulated [Fe(bpy)3]2+ are correctly predicted as LS species and that (ii) the encapsulation of both complexes translates into a destabilization of their HS state with respect to their LS state. The increase of the HS-LS energy difference is smaller for [Co(bpy)3]2+ than [Fe(bpy)3]2+ because the HS-LS molecular volume difference ΔVHL in [Co(bpy)3]2+ is ∼50% smaller than in [Fe(bpy)3]2+. Periodic DFT calculations performed on crystalline [M(bpy)3]2+@Y show that the employed [M(bpy)3]2+@YSM supramolecular model allows the influence of encapsulation on the geometry and the spin-state energetics of [M(bpy)3]2+ (M = Fe, Co) to be quantitatively captured.
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Affiliation(s)
- Andrea Missana
- Université de Genève, 30 quai Ernest-Ansermet, CH-1211Genève 4, Switzerland
| | - Andreas Hauser
- Université de Genève, 30 quai Ernest-Ansermet, CH-1211Genève 4, Switzerland
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19
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Rettig A, Shee J, Lee J, Head-Gordon M. Revisiting the Orbital Energy-Dependent Regularization of Orbital-Optimized Second-Order Møller-Plesset Theory. J Chem Theory Comput 2022; 18:5382-5392. [PMID: 36050889 DOI: 10.1021/acs.jctc.2c00641] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Optimizing orbitals in the presence of electron correlation, as in orbital-optimized second-order Møller-Plesset perturbation theory (OOMP2), can remove artifacts associated with mean-field orbitals such as spin contamination and artificial symmetry-breaking. However, OOMP2 is known to suffer from divergent correlation energies in regimes of small orbital energy gaps. To address this issue, several approaches to amplitude regularization have been explored, with those featuring energy-gap-dependent regularizers appearing to be most transferable and physically justifiable. For instance, κ-OOMP2 was shown to address the energy divergence issue in, for example, bond-breaking processes while offering a significant improvement in accuracy for the W4-11 thermochemistry data set, and a parameter of κ = 1.45 was recommended. A more recent investigation of regularized MP2 with Hartree-Fock orbitals revealed that stronger regularization (i.e., smaller values of κ) than what had previously been recommended for κ-OOMP2 may offer huge improvements in certain cases such as noncovalent interactions while retaining a high level of accuracy for main-group thermochemistry data sets. In this study, we investigate the transferability of those findings to κ-OOMP2 and assess the implications of stronger regularization on the ability of κ-OOMP2 to diagnose strong static correlation. We found similar results using κ-OOMP2 for several main-group thermochemistry, barrier height, and noncovalent interaction data sets including both closed shell and open shell species. However, stronger regularization yielded substantially higher accuracy for open-shell transition-metal (TM) thermochemistry and is necessary to provide qualitatively correct spin symmetry breaking behavior for several large and electrochemically relevant TM systems. We therefore find a single κ value insufficient to treat all systems using κ-OOMP2.
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Affiliation(s)
- Adam Rettig
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - James Shee
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Joonho Lee
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Martin Head-Gordon
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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20
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Stroscio GD, Zhou C, Truhlar DG, Gagliardi L. Multiconfiguration Pair-Density Functional Theory Calculations of Iron(II) Porphyrin: Effects of Hybrid Pair-Density Functionals and Expanded RAS and DMRG Active Spaces on Spin-State Orderings. J Phys Chem A 2022; 126:3957-3963. [PMID: 35674705 DOI: 10.1021/acs.jpca.2c02347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron(II) porphyrins play critical roles in enzymes and synthetic catalysts. Computationally determining the spin-state ordering for even the unsubstituted iron(II) porphyrin (FeP) is challenging due to its large size. Multiconfiguration pair-density functional theory (MC-PDFT), a method capable of accurately capturing correlation with lower cost than comparably accurate methods, was previously used to predict a triplet ground state for FeP across a wide range of active spaces up to (34e, 35o). The purpose of this present MC-PDFT study is to determine the effects of including nonlocal exchange in the energy calculation and of using a larger active space size [DMRG(40e, 42o) and RAS(40, 2, 2; 16, 6, 20)] on the calculated FeP spin-state ordering. The recently developed hybrid MC-PDFT method, which uses a weighted average of the MC-PDFT energy and the energy expectation value of the reference wave function, is applied with a weight of the reference wave function energy of λ. We find that increasing λ stabilizes the quintet relative to the triplets. The hybrid tPBE0 functional (tPBE with λ set to 0.25) consistently predicts a triplet ground state with the quintet lying above by 0.10-0.16 eV, depending on the reference wave function. These values are particularly interesting in light of tPBE0's very strong performance for a diverse set of other systems.
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Affiliation(s)
- Gautam D Stroscio
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, University of Chicago, Chicago, Illinois 60637-5418, United States.,Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Chen Zhou
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Laura Gagliardi
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, University of Chicago, Chicago, Illinois 60637-5418, United States.,Argonne National Laboratory, Lemont, Illinois 60439, United States
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21
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Vitale E, Li Manni G, Alavi A, Kats D. FCIQMC-Tailored Distinguishable Cluster Approach: Open-Shell Systems. J Chem Theory Comput 2022; 18:3427-3437. [PMID: 35522217 PMCID: PMC9202306 DOI: 10.1021/acs.jctc.2c00059] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
A recently proposed
tailored approach based on the distinguishable
cluster method and the stochastic FCI solver, FCIQMC [J. Chem.
Theory Comput. 2020, 16, 5621], is extended to open-shell
molecular systems. The method is employed to calculate spin gaps of
various Fe(II) complexes, including a Fe(II) porphyrin model system.
Both distinguishable cluster and fully relaxed CASSCF natural orbitals
were used in this work as reference for the subsequent tailored distinguishable
cluster calculations. The distinguishable cluster natural orbitals
occupation numbers were also used as an aid to the selection of the
active space. The effect of the active space sizes and of the explicit
correlation correction (F12) onto the predicted spin gaps is investigated.
The tailored distinguishable cluster with singles and doubles yields
consistently more accurate results compared to the tailored coupled
cluster with singles and doubles.
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Affiliation(s)
- Eugenio Vitale
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Giovanni Li Manni
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Ali Alavi
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany.,Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Daniel Kats
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
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22
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Rask AE, Zimmerman PM. The many-body electronic interactions of Fe(II)–porphyrin. J Chem Phys 2022; 156:094110. [DOI: 10.1063/5.0079310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Fe(II)–porphyrin complexes exhibit a diverse range of electronic interactions between the metal and macrocycle. Herein, the incremental full configuration interaction method is applied to the entire space of valence orbitals of a Fe(II)–porphyrin model using a modest basis set. A novel visualization framework is proposed to analyze individual many-body contributions to the correlation energy, providing detailed maps of this complex’s highly correlated electronic structure. This technique is used to parse the numerous interactions of two low-lying triplet states (3A2g and 3Eg) and to show that strong metal d–d and macrocycle π–π orbital interactions preferentially stabilize the 3A2g state. d–π interactions, on the other hand, preferentially stabilize the 3Eg state and primarily appear when correlating six electrons at a time. Ultimately, the Fe(II)–porphyrin model’s full set of 88 valence electrons are correlated in 275 orbitals, showing the interactions up to the 4-body level, which covers the great majority of correlations in this system.
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Affiliation(s)
- A. E. Rask
- Department of Chemistry, University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, USA
| | - P. M. Zimmerman
- Department of Chemistry, University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, USA
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23
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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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24
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Wu Q, Wang G, Liu M. On the Sensitivity to Density-Functional Approximations for CO Binding Energies of Single-Atom Catalysts in Nitrogen-Doped Graphene. Chemphyschem 2022; 23:e202100787. [PMID: 35146865 DOI: 10.1002/cphc.202100787] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/13/2021] [Indexed: 12/27/2022]
Abstract
Density functional theory (DFT) methods are the working horse in screening new catalytic materials. They are widely used to predict trends in binding energies, which are then used to compare the activity of different materials. The binding strength of CO is an important descriptor to the CO2 reduction catalytic activity of the single transition metal atoms embedded on nitrogen-doped graphene (TM/NG). In this work, however, we show that CO binding strengths in different TM/NG has very different sensitivity to DFT methods. Specifically, Fe/NG CO binding energy changes dramatically with the percentage of exact exchange in the functional; Co/NG does less so, while Ni/NG nearly has no change. Such varying behaviors is a direct result of different local spin configurations, similar to the performance of DFT methods for metal porphyrin complexes. Therefore, caution should be exercised when using DFT binding energies for quantitative predictions in TM/NG single atom catalysis.
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Affiliation(s)
- Qin Wu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Guangjin Wang
- School of Materials Science and Hydrogen Energy, Foshan University, Foshan, 528000, P. R. China
| | - Mingjie Liu
- Department of Chemical Engineering, MIT, Cambridge, MA 02139, USA
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25
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Graham DS, Wen X, Chulhai DV, Goodpaster J. Huzinaga Projection Embedding for Efficient and Accurate Energies of Systems with Localized Spin-densities. J Chem Phys 2022; 156:054112. [DOI: 10.1063/5.0076493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Xuelan Wen
- Department of Chemistry, University of Minnesota Twin Cities, United States of America
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26
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Chen X, Cao C, Yang YF, She YB. Computational Insights into Different Regioselectivities in Ir-Porphyrin-Catalyzed C–H Insertion Reaction of Quinoid Carbene. Org Chem Front 2022. [DOI: 10.1039/d1qo01727f] [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
The mechanisms and regioselectivities of Ir-porphyrin-catalyzed C–H insertion reaction of quinoid carbene (QC) were investigated with density functional theory (DFT) calculations. The competing catalytic cycles were identified as the hydrogen-atom...
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27
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Weser O, Guther K, Ghanem K, Li Manni G. Stochastic Generalized Active Space Self-Consistent Field: Theory and Application. J Chem Theory Comput 2021; 18:251-272. [PMID: 34898215 PMCID: PMC8757470 DOI: 10.1021/acs.jctc.1c00936] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An algorithm to perform stochastic generalized active space calculations, Stochastic-GAS, is presented, that uses the Slater determinant based FCIQMC algorithm as configuration interaction eigensolver. Stochastic-GAS allows the construction and stochastic optimization of preselected truncated configuration interaction wave functions, either to reduce the computational costs of large active space wave function optimizations, or to probe the role of specific electron correlation pathways. As for the conventional GAS procedure, the preselection of the truncated wave function is based on the selection of multiple active subspaces while imposing restrictions on the interspace excitations. Both local and cumulative minimum and maximum occupation number constraints are supported by Stochastic-GAS. The occupation number constraints are efficiently encoded in precomputed probability distributions, using the precomputed heat bath algorithm, which removes nearly all runtime overhead of GAS. This strategy effectively allows the FCIQMC dynamics to a priori exclude electronic configurations that are not allowed by GAS restrictions. Stochastic-GAS reduced density matrices are stochastically sampled, allowing orbital relaxations via Stochastic-GASSCF, and direct evaluation of properties that can be extracted from density matrices, such as the spin expectation value. Three test case applications have been chosen to demonstrate the flexibility of Stochastic-GAS: (a) the Stochastic-GASSCF [5·(6, 6)] optimization of a stack of five benzene molecules, that shows the applicability of Stochastic-GAS toward fragment-based chemical systems; (b) an uncontracted stochastic MRCISD calculation that correlates 96 electrons and 159 molecular orbitals, and uses a large (32, 34) active space reference wave function for an Fe(II)-porphyrin model system, showing how GAS can be applied to systematically recover dynamic electron correlation, and how in the specific case of the Fe(II)-porphyrin dynamic correlation further differentially stabilizes the 3Eg over the 5A1g spin state; (c) the study of an Fe4S4 cluster's spin-ladder energetics via highly truncated stochastic-GAS [4·(5, 5)] wave functions, where we show how GAS can be applied to understand the competing spin-exchange and charge-transfer correlating mechanisms in stabilizing different spin-states.
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Affiliation(s)
- Oskar Weser
- Max-Planck-Institute for Solid State Research, Stuttgart, 70569, Germany
| | - Kai Guther
- Max-Planck-Institute for Solid State Research, Stuttgart, 70569, Germany.,RIKEN Center for Computational Science, 7-1-26 minatojima-minami, Chuo Kobe 650-0047, Japan
| | - Khaldoon Ghanem
- Max-Planck-Institute for Solid State Research, Stuttgart, 70569, Germany
| | - Giovanni Li Manni
- Max-Planck-Institute for Solid State Research, Stuttgart, 70569, Germany
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Oszajca M, Drabik G, Radoń M, Franke A, van Eldik R, Stochel G. Experimental and Computational Insight into the Mechanism of NO Binding to Ferric Microperoxidase. The Likely Role of Tautomerization to Account for the pH Dependence. Inorg Chem 2021; 60:15948-15967. [PMID: 34476946 DOI: 10.1021/acs.inorgchem.1c00933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
According to the current paradigm, the metal-hydroxo bond in a six-coordinate porphyrin complex is believed to be significantly less reactive in ligand substitution than the analogous metal-aqua bond, due to a much higher strength of the former bond. Here, we report kinetic studies for nitric oxide (NO) binding to a heme-protein model, acetylated microperoxidase-11 (AcMP-11), that challenge this paradigm. In the studied pH range 7.4-12.6, ferric AcMP-11 exists in three acid-base forms, assigned in the literature as [(AcMP-11)FeIII(H2O)(HisH)] (1), [(AcMP-11)FeIII(OH)(HisH)] (2), and [(AcMP-11)FeIII(OH)(His-)] (3). From the pH dependence of the second-order rate constant for NO binding (kon), we determined individual rate constants characterizing forms 1-3, revealing only a ca. 10-fold decrease in the NO binding rate on going from 1 (kon(1) = 3.8 × 106 M-1 s-1) to 2 (kon(2) = 4.0 × 105 M-1 s-1) and the inertness of 3. These findings lead to the abandonment of the dissociatively activated mechanism, in which the reaction rate can be directly correlated with the Fe-OH bond energy, as the mechanistic explanation for the process with regard to 2. The reactivity of 2 is accounted for through the existence of a tautomeric equilibrium between the major [(AcMP-11)FeIII(OH)(HisH)] (2a) and minor [(AcMP-11)FeIII(H2O)(His-)] (2b) species, of which the second one is assigned as the NO binding target due to its labile Fe-OH2 bond. The proposed mechanism is further substantiated by quantum-chemical calculations, which confirmed both the significant labilization of the Fe-OH2 bond in the [(AcMP-11)FeIII(H2O)(His-)] tautomer and the feasibility of the tautomer formation, especially after introducing empirical corrections to the computed relative acidities of the H2O and HisH ligands based on the experimental pKa values. It is shown that the "effective lability" of the axial ligand (OH-/H2O) in 2 may be comparable to the lability of the H2O ligand in 1.
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Affiliation(s)
- Maria Oszajca
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Gabriela Drabik
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Mariusz Radoń
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Alicja Franke
- Department of Chemistry, Ludwigs-Maximilians University, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - Rudi van Eldik
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
- Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Egerlandstr. 1, 91058 Erlangen, Germany
- Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland
| | - Grażyna Stochel
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
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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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Tarrago M, Römelt C, Nehrkorn J, Schnegg A, Neese F, Bill E, Ye S. Experimental and Theoretical Evidence for an Unusual Almost Triply Degenerate Electronic Ground State of Ferrous Tetraphenylporphyrin. Inorg Chem 2021; 60:4966-4985. [PMID: 33739093 DOI: 10.1021/acs.inorgchem.1c00031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Iron porphyrins exhibit unrivalled catalytic activity for electrochemical CO2-to-CO conversion. Despite intensive experimental and computational studies in the last 4 decades, the exact nature of the prototypical square-planar [FeII(TPP)] complex (1; TPP2- = tetraphenylporphyrinate dianion) remained highly debated. Specifically, its intermediate-spin (S = 1) ground state was contradictorily assigned to either a nondegenerate 3A2g state with a (dxy)2(dz2)2(dxz,yz)2 configuration or a degenerate 3Egθ state with a (dxy)2(dxz,yz)3(dz2)1/(dz2)2(dxy)1(dxz,yz)3 configuration. To address this question, we present herein a comprehensive, spectroscopy-based theoretical and experimental electronic-structure investigation on complex 1. Highly correlated wave-function-based computations predicted that 3A2g and 3Egθ are well-isolated from other triplet states by ca. 4000 cm-1, whereas their splitting ΔA-E is on par with the effective spin-orbit coupling (SOC) constant of iron(II) (≈400 cm-1). Therfore, we invoked an effective Hamiltonian (EH) operating on the nine magnetic sublevels arising from SOC between the 3A2g and 3Egθ states. This approach enabled us to successfully simulate all spectroscopic data of 1 obtained by variable-temperature and variable-field magnetization, applied-field 57Fe Mössbauer, and terahertz electron paramagnetic resonance measurements. Remarkably, the EH contains only three adjustable parameters, namely, the energy gap without SOC, ΔA-E, an angle θ that describes the mixing of (dxy)2(dxz,yz)3(dz2)1 and (dz2)2(dxy)1(dxz,yz)3 configurations, and the ⟨rd-3⟩ expectation value of the iron d orbitals that is necessary to estimate the 57Fe magnetic hyperfine coupling tensor. The EH simulations revealed that the triplet ground state of 1 is genuinely multiconfigurational with substantial parentages of both 3A2g (<88%) and 3Eg (>12%), owing to their accidental near-triple degeneracy with ΔA-E = +950 cm-1. As a consequence of this peculiar electronic structure, 1 exhibits a huge effective magnetic moment (4.2 μB at 300 K), large temperature-independent paramagnetism, a large and positive axial zero-field splitting, strong easy-plane magnetization (g⊥ ≈ 3 and g∥ ≈ 1.7) and a large and positive internal field at the 57Fe nucleus aligned in the xy plane. Further in-depth analyses suggested that g⊥ ≫ g∥ is a general spectroscopic signature of near-triple orbital degeneracy with more than half-filled pseudodegenerate orbital sets. Implications of the unusual electronic structure of 1 for CO2 reduction are discussed.
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Affiliation(s)
- Maxime Tarrago
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Christina Römelt
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Joscha Nehrkorn
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Alexander Schnegg
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Shengfa Ye
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany.,State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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Cheng C, Hayashi S. Ab Initio Evaluation of the Redox Potential of Cytochrome c. J Chem Theory Comput 2021; 17:1194-1207. [PMID: 33459006 DOI: 10.1021/acs.jctc.0c00889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Various biochemical activities of metabolism and biosynthesis are fulfilled by redox processes with explicit electron exchange, which furnish redox enzymes with high chemical reactivity. However, theoretical investigation of a redox process, which simultaneously involves a complex electronic change at a redox metal center and conformational reorganization of the surrounding protein environment coupled to the electronic change, requires computationally conflicting approaches, highly accurate quantum chemical calculations, and long-time molecular dynamics (MD) simulations, limiting the physicochemical understanding of biological redox processes. Here, we theoretically examined a redox process of cytochrome c by means of a hybrid molecular simulation technique, which enables one to consistently treat the redox center at the ab initio quantum chemistry level of theory and the protein reorganization with long-time MD simulations on the microsecond timescale. The calculations successfully evaluated a large absolute redox potential, 4.34 eV, with errors of only 0.03 to 0.34 eV to the experimental ones without any problem-specific empirical parameters. Through the long-time MD sampling, large and nonlinear reorganization of the protein environment was unveiled and the molecular determinants for the redox potential were identified. The present ab initio approach significantly expands the applicability of theoretical investigation to biological redox systems with more electronically complicated redox centers such as polynuclear transition metal complexes.
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Affiliation(s)
- Cheng Cheng
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Shigehiko Hayashi
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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Roos G, Harvey JN. Histidine versus Cysteine-Bearing Heme-Dependent Halogen Peroxidases: Parallels and Differences for Cl - Oxidation. J Phys Chem B 2021; 125:74-85. [PMID: 33350832 DOI: 10.1021/acs.jpcb.0c09409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The homodimeric myeloperoxidase (MPO) features a histidine as a proximal ligand and a sulfonium linkage covalently attaching the heme porphyrin ring to the protein. MPO is able to catalyze Cl- oxidation with about the same efficiency as chloroperoxidase at pH 7.0. In this study, we seek to explore the parallels and differences between the histidine and cysteine heme-dependent halogen peroxidases. Transition states, reaction barriers, and relevant thermodynamic properties are calculated on protein models. Together with electronic structure calculations, it gives an overview of the reaction mechanisms and of the factors that determine the selectivity between one- and two-electron paths. Conclusions point to the innate oxidizing nature of MPO with the ester and sulfonium linkages hiking up the reactivity to enable chloride oxidation. The installation of a deprotonated imidazolate as a proximal ligand does not shift the equilibrium from one- to two-electron events without influencing the chemistry of the oxidation reaction.
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Affiliation(s)
- Goedele Roos
- UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, University of Lille, CNRS, UMR 8576, F-59000 Lille, France
| | - Jeremy N Harvey
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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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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Miyagawa K, Isobe H, Shoji M, Kawakami T, Yamanaka S, Yamaguchi K. A three states model for hydrogen abstraction reactions with the cytochrome P450 compound I is revisited. Isolobal and isospin analogy among Fe(IV)=O, O = O and O. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2020.112902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Yamaguchi K, Miyagawa K, Isobe H, Shoji M, Kawakami T, Yamanaka S. Isolobal and isospin analogy between organic and inorganic open-shell molecules—Application to oxygenation reactions by active oxygen and oxy-radicals and water oxidation in the native and artificial photosynthesis. ADVANCES IN QUANTUM CHEMISTRY 2021. [DOI: 10.1016/bs.aiq.2021.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
Applications of density-functional theory (DFT) in computational chemistry rely on an approximate exchange-correlation (xc) functional. However, existing approximations can fail dramatically for open-shell molecules, in particular for transition-metal complexes or radicals. Most importantly, predicting energy differences between different spin-states with approximate exchange-correlation functionals remains extremely challenging. Formally, it is known that the exact xc functional should be spin-state dependent, but none of the available approximations feature such an explicit spin-state dependence [C. R. Jacob and M. Reiher, Int. J. Quantum Chem., 2012, 112, 3661-3684]. Thus, to find novel approximations for the xc functional for open-shell systems, the development of spin-state dependent xc functionals appears to be a promising avenue. Here, we set out to shed light on the spin-state dependence of the xc functional by investigating the underlying xc holes, which we extract from configuration interaction calculations for model systems. We analyze the similarities and differences between the xc holes of the lowest-energy singlet and triplet states of the dihydrogen molecule, the helium atom, and the lithium dimer. To shed further light on the spin-state dependence of these xc holes we also discuss exact conditions that can be derived from the spin structure of the reduced two-electron density matrix. Altogether, our results suggest several possible routes towards the construction of explicitly spin-state dependent approximations for the xc functional.
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Affiliation(s)
- Julia Brüggemann
- Technische Universität Braunschweig, Institute of Physical and Theoretical Chemistry, Gaußstraße 17, 38106 Braunschweig, Germany.
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Sours T, Patel A, Nørskov J, Siahrostami S, Kulkarni A. Circumventing Scaling Relations in Oxygen Electrochemistry Using Metal-Organic Frameworks. J Phys Chem Lett 2020; 11:10029-10036. [PMID: 33179928 DOI: 10.1021/acs.jpclett.0c02889] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
It has been well-established that unfavorable scaling relationships between *OOH, *OH, and *O are responsible for the high overpotentials associated with oxygen electrochemistry. A number of strategies have been proposed for breaking these linear constraints for traditional electrocatalysts (e.g., metals, alloys, metal-doped carbons); such approaches have not yet been validated experimentally for heterogeneous catalysts. Development of a new class of catalysts capable of circumventing such scaling relations remains an ongoing challenge in the field. In this work, we use density functional theory (DFT) calculations to demonstrate that bimetallic porphyrin-based MOFs (PMOFs) are an ideal materials platform for rationally designing the 3-D active site environments for oxygen reduction reaction (ORR). Specifically, we show that the *OOH binding energy and the theoretical limiting potential can be optimized by appropriately tuning the transition metal active site, the oxophilic spectator, and the MOF topology. Our calculations predict theoretical limiting potentials as high as 1.07 V for Fe/Cr-PMOF-Al, which exceeds the Pt/C benchmark for 4e ORR. More broadly, by highlighting their unique characteristics, this work aims to establish bimetallic porphyrin-based MOFs as a viable materials platform for future experimental and theoretical ORR studies.
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Affiliation(s)
- Tyler Sours
- Department of Chemical Engineering, University of California, Davis, Davis, California 95616, United States
| | - Anjli Patel
- SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Jens Nørskov
- Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Samira Siahrostami
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Ambarish Kulkarni
- Department of Chemical Engineering, University of California, Davis, Davis, California 95616, United States
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Römer A, Hasecke L, Blöchl P, Mata RA. A Review of Density Functional Models for the Description of Fe(II) Spin-Crossover Complexes. Molecules 2020; 25:E5176. [PMID: 33172067 PMCID: PMC7664392 DOI: 10.3390/molecules25215176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 10/30/2020] [Accepted: 11/02/2020] [Indexed: 11/21/2022] Open
Abstract
Spin-crossover (SCO) materials have for more than 30 years stood out for their vast application potential in memory, sensing and display devices. To reach magnetic multistability conditions, the high-spin (HS) and low-spin (LS) states have to be carefully balanced by ligand field stabilization and spin-pairing energies. Both effects could be effectively modelled by electronic structure theory, if the description would be accurate enough to describe these concurrent influences to within a few kJ/mol. Such a milestone would allow for the in silico-driven development of SCO complexes. However, so far, the ab initio simulation of such systems has been dominated by general gradient approximation density functional calculations. The latter can only provide the right answer for the wrong reasons, given that the LS states are grossly over-stabilized. In this contribution, we explore different venues for the parameterization of hybrid functionals. A fitting set is provided on the basis of explicitly correlated coupled cluster calculations, with single- and multi-dimensional fitting approaches being tested to selected classes of hybrid functionals (hybrid, range-separated, and local hybrid). Promising agreement to benchmark data is found for a rescaled PBE0 hybrid functional and a local version thereof, with a discussion of different atomic exchange factors.
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Affiliation(s)
- Anton Römer
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany; (A.R.); (L.H.)
| | - Lukas Hasecke
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany; (A.R.); (L.H.)
| | - Peter Blöchl
- Institut für Theoretische Physik, Technische Universität Clausthal, Leibnizstraße 10, 38678 Clausthal-Zellerfeld, Germany;
- Institut für Theoretische Physik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Ricardo A. Mata
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany; (A.R.); (L.H.)
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39
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Halson JJ, Anderson RJ, Booth GH. Improved stochastic multireference perturbation theory for correlated systems with large active spaces. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1802072] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- James J. Halson
- Department of Physics, King's College London, Strand, London, UK
| | | | - George H. Booth
- Department of Physics, King's College London, Strand, London, UK
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Pierloot K, Phung QM, Ghosh A. Electronic Structure of Neutral and Anionic Iron–Nitrosyl Corrole. A Multiconfigurational and Density Matrix Renormalization Group Investigation. Inorg Chem 2020; 59:11493-11502. [DOI: 10.1021/acs.inorgchem.0c01312] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Kristine Pierloot
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
| | - Quan Manh Phung
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya 464-8602, Japan
| | - Abhik Ghosh
- Department of Chemistry, UiT-The Arctic University of Norway, N-9037 Tromsø, Norway
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Zhang YQ, Chen JY, Siegbahn PEM, Liao RZ. Harnessing Noninnocent Porphyrin Ligand to Circumvent Fe-Hydride Formation in the Selective Fe-Catalyzed CO2 Reduction in Aqueous Solution. ACS Catal 2020. [DOI: 10.1021/acscatal.0c00559] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Ya-Qiong Zhang
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jia-Yi Chen
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Per E. M. Siegbahn
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm 10691, Sweden
| | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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Yang Y, Zhang X, Zhong LP, Lan J, Li X, Li CC, Chung LW. Unusual KIE and dynamics effects in the Fe-catalyzed hetero-Diels-Alder reaction of unactivated aldehydes and dienes. Nat Commun 2020; 11:1850. [PMID: 32296076 PMCID: PMC7160212 DOI: 10.1038/s41467-020-15599-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/13/2020] [Indexed: 12/30/2022] Open
Abstract
Hetero-Diels-Alder (HDA) reaction is an important synthetic method for many natural products. An iron(III) catalyst was developed to catalyze the challenging HDA reaction of unactivated aldehydes and dienes with high selectivity. Here we report extensive density-functional theory (DFT) calculations and molecular dynamics simulations that show effects of iron (including its coordinate mode and/or spin state) on the dynamics of this reaction: considerably enhancing dynamically stepwise process, broadening entrance channel and narrowing exit channel from concerted asynchronous transition states. Also, our combined computational and experimental secondary KIE studies reveal unexpectedly large KIE values for the five-coordinate pathway even with considerable C-C bond forming, due to equilibrium isotope effect from the change in the metal coordination. Moreover, steric and electronic effects are computationally shown to dictate the C=O chemoselectivity for an α,β-unsaturated aldehyde, which is verified experimentally. Our mechanistic study may help design homogeneous, heterogeneous and biological catalysts for this challenging reaction.
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Affiliation(s)
- Yuhong Yang
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xiaoyong Zhang
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Li-Ping Zhong
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Jialing Lan
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xin Li
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Chuang-Chuang Li
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Lung Wa Chung
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China.
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Lee J, Malone FD, Morales MA. Utilizing Essential Symmetry Breaking in Auxiliary-Field Quantum Monte Carlo: Application to the Spin Gaps of the C36 Fullerene and an Iron Porphyrin Model Complex. J Chem Theory Comput 2020; 16:3019-3027. [DOI: 10.1021/acs.jctc.0c00055] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joonho Lee
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Fionn D. Malone
- Quantum Simulations Group, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551, United States
| | - Miguel A. Morales
- Quantum Simulations Group, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551, United States
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44
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A detailed analysis of the spin-crossover reaction of H 2S binding to heme and the six-coordinated FeP(Im)-HS - porphyrin complex. J Inorg Biochem 2020; 206:111049. [PMID: 32171934 DOI: 10.1016/j.jinorgbio.2020.111049] [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: 10/28/2019] [Revised: 02/21/2020] [Accepted: 02/22/2020] [Indexed: 11/23/2022]
Abstract
The potential energy surfaces of the H2S binding to iron-porphyrin (FeP) with the imidazole (Im) ligand via intersystem crossings are investigated by using density functional theory. The minimum energy intersystem crossing point (MEISCP) between the quintet and triplet states (MEISCPTQ) for the Fe(II)P(Im)-H2S complex is located at a Fe-S distance of 3.39 Å with only 1.1 kcal/mol above the quintet state minimum. The second spin-crossover point, where a change from the triplet to the singlet state occurs, comes at a much shorter Fe-S distance of 2.79 Å, and the MEISCPST is located at 3.7 kcal/mol above the triplet state minimum. The nature of the chemical bonding along the Fe-S reaction coordinate from the ground state singlet to the quintet state along the path to the separated species is analyzed. An inspection of the vibrational modes reveals that the largest contribution to the triplet-quintet transition around the quintet and triplet state minimum comes from the symmetric shrinking of the pyrrole units of the porphyrin ring, indicating that the related reaction coordinate plays a main role in the intersystem crossing. The fully optimized structures of the Fe(II)P(Im)-HS- complex corresponding to three different spin multiplicities (M = 1, 3, 5) are characterized by a bent Fe-H-S conformation. The binding of the hydrosulfide anion to Fe(II)P(Im) in the quintet state induces a 0.2 Å displacement of the Fe atom out of the nitrogen porphyrin (Npyr) plane. The fully optimized structure of the ground state of Fe(II)P(Im)-HS- agrees well with experimental data for the corresponding heme models.
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45
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Stoneburner SJ, Truhlar DG, Gagliardi L. Transition Metal Spin-State Energetics by MC-PDFT with High Local Exchange. J Phys Chem A 2020; 124:1187-1195. [PMID: 31962045 DOI: 10.1021/acs.jpca.9b10772] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The energetics of the spin states of transition metal complexes have been explored with a variety of electronic structure methods, but the calculations require a compromise between accuracy and affordability. In this work, the spin splittings of several iron complexes are studied with multiconfiguration pair-density functional theory (MC-PDFT). The results are compared to previously published results obtained by complete active space second-order perturbation theory (CASPT2) and CASPT2 with coupled-cluster semicore correlation (CASPT2/CC). In contrast to CASPT2's systematic overstabilization of high-spin states with respect to the CASPT2/CC reference, MC-PDFT with the tPBE on-top functional understabilizes high-spin states. This systematic understabilization is largely corrected by revising the exchange and correlation contributions to the on-top functional using the high local-exchange approximation (tPBE-HLE). Moreover, tPBE-HLE correctly predicts the spin of the ground state in most cases, while CASPT2 incorrectly predicts high-spin ground states in all cases. This is encouraging for practical work because tPBE and tPBE-HLE are faster than CASPT2 by a factor of 50 even in a moderately sized example.
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Affiliation(s)
- Samuel J Stoneburner
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455-0431 , United States
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455-0431 , United States
| | - Laura Gagliardi
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455-0431 , United States
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46
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Antalík A, Nachtigallová D, Lo R, Matoušek M, Lang J, Legeza Ö, Pittner J, Hobza P, Veis L. Ground state of the Fe(ii)-porphyrin model system corresponds to quintet: a DFT and DMRG-based tailored CC study. Phys Chem Chem Phys 2020; 22:17033-17037. [DOI: 10.1039/d0cp03086d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fe(ii)-porphyrins play an important role in many reactions, due to their closely lying spin states. We present a thorough study of a Fe(ii)-porphyrin model system, in which we examine how the geometrical parameters influence its spin state ordering.
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Affiliation(s)
- Andrej Antalík
- J. Heyrovský Institute of Physical Chemistry
- Academy of Sciences of the Czech Republic
- 18223 Prague 8
- Czech Republic
- Faculty of Mathematics and Physics
| | - Dana Nachtigallová
- Institute of Organic Chemistry and Biochemistry
- Academy of Sciences of the Czech Republic
- 16610 Prague 6
- Czech Republic
- Regional Centre of Advanced Technologies and Materials
| | - Rabindranath Lo
- Institute of Organic Chemistry and Biochemistry
- Academy of Sciences of the Czech Republic
- 16610 Prague 6
- Czech Republic
- Regional Centre of Advanced Technologies and Materials
| | - Mikuláš Matoušek
- J. Heyrovský Institute of Physical Chemistry
- Academy of Sciences of the Czech Republic
- 18223 Prague 8
- Czech Republic
- Faculty of Mathematics and Physics
| | - Jakub Lang
- J. Heyrovský Institute of Physical Chemistry
- Academy of Sciences of the Czech Republic
- 18223 Prague 8
- Czech Republic
| | - Örs Legeza
- Strongly Correlated Systems “Lendület” Research group
- Wigner Research Centre for Physics
- Budapest
- Hungary
| | - Jiří Pittner
- J. Heyrovský Institute of Physical Chemistry
- Academy of Sciences of the Czech Republic
- 18223 Prague 8
- Czech Republic
| | - Pavel Hobza
- Institute of Organic Chemistry and Biochemistry
- Academy of Sciences of the Czech Republic
- 16610 Prague 6
- Czech Republic
- Regional Centre of Advanced Technologies and Materials
| | - Libor Veis
- J. Heyrovský Institute of Physical Chemistry
- Academy of Sciences of the Czech Republic
- 18223 Prague 8
- Czech Republic
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47
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Neale SE, Pantazis DA, Macgregor SA. Accurate computed spin-state energetics for Co(iii) complexes: implications for modelling homogeneous catalysis. Dalton Trans 2020; 49:6478-6487. [DOI: 10.1039/d0dt00993h] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
DLPNO-CCSD(T) calculations provide accurate spin state energetics for a range of Co(iii) complexes and so represent a promising approach to modelling homogeneous catalysis based on Co(iii) species.
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Affiliation(s)
- Samuel E. Neale
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- United Kingdom
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48
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Alipour M, Izadkhast T. Appraising spin-state energetics in transition metal complexes using double-hybrid models: accountability of SOS0-PBESCAN0-2(a) as a promising paradigm. Phys Chem Chem Phys 2020; 22:9388-9404. [DOI: 10.1039/d0cp00807a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Through a comprehensive survey, reliable double-hybrid models have been validated and proposed for spin-state energetics in transition metal complexes.
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Affiliation(s)
- Mojtaba Alipour
- Department of Chemistry
- College of Sciences
- Shiraz University
- Shiraz 71946-84795
- Iran
| | - Tahereh Izadkhast
- Department of Chemistry
- College of Sciences
- Shiraz University
- Shiraz 71946-84795
- Iran
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49
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Wang Q, Chen X, Li G, Chen Q, Yang YF, She YB. Computational Exploration of Chiral Iron Porphyrin-Catalyzed Asymmetric Hydroxylation of Ethylbenzene Where Stereoselectivity Arises from π-π Stacking Interaction. J Org Chem 2019; 84:13755-13763. [PMID: 31599588 DOI: 10.1021/acs.joc.9b01989] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The mechanism and origins of stereoselectivity of chiral iron porphyrin-catalyzed asymmetric hydroxylation of ethylbenzene were explored with density functional theory. The hydrogen atom abstraction is the rate- and stereoselectivity-determining step. In good agreement with experimental results, the formation of the (R)-1-phenylethanol product is found to be the most favorable pathway. The transition state of hydrogen atom abstraction which leads to the (S)-1-phenylethanol product is unfavorable by 1.7 kcal/mol compared to the corresponding transition state which leads to the (R)-1-phenylethanol product. Enantioselectivity arises from an attractive π-π stacking interaction between the phenyl group of ethylbenzene substrate and the naphthyl group of the porphyrin ligand.
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Affiliation(s)
- Qunmin Wang
- College of Chemical Engineering , Zhejiang University of Technology , Hangzhou , Zhejiang 310014 , China
| | - Xiahe Chen
- College of Chemical Engineering , Zhejiang University of Technology , Hangzhou , Zhejiang 310014 , China
| | - Guijie Li
- College of Chemical Engineering , Zhejiang University of Technology , Hangzhou , Zhejiang 310014 , China
| | - Qidong Chen
- College of Chemical Engineering , Zhejiang University of Technology , Hangzhou , Zhejiang 310014 , China
| | - Yun-Fang Yang
- College of Chemical Engineering , Zhejiang University of Technology , Hangzhou , Zhejiang 310014 , China
| | - Yuan-Bin She
- College of Chemical Engineering , Zhejiang University of Technology , Hangzhou , Zhejiang 310014 , China
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50
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Pandharkar R, Hermes MR, Cramer CJ, Gagliardi L. Spin-State Ordering in Metal-Based Compounds Using the Localized Active Space Self-Consistent Field Method. J Phys Chem Lett 2019; 10:5507-5513. [PMID: 31429583 DOI: 10.1021/acs.jpclett.9b02077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Quantitatively accurate calculations for spin-state ordering in transition-metal complexes typically demand a robust multiconfigurational treatment. The poor scaling of such methods with increasing size makes them impractical for large, strongly correlated systems. Density matrix embedding theory (DMET) is a fragmentation approach that can be used to specifically address this challenge. The single-determinantal bath framework of DMET is applicable in many situations, but it has been shown to perform poorly for molecules characterized by strong correlation when a multiconfigurational self-consistent field solver is used. To ameliorate this problem, the localized active space self-consistent field (LASSCF) method was recently described. In this work, LASSCF is applied to predict spin-state energetics in mono- and di-iron systems, and we show that the model offers an accuracy equivalent to that of CASSCF but at a substantially lower computational cost. Performance as a function of basis set and active space is also examined.
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Affiliation(s)
- Riddhish Pandharkar
- Department of Chemistry, Chemical Theory Center, and The Minnesota Supercomputing Institute , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Matthew R Hermes
- Department of Chemistry, Chemical Theory Center, and The Minnesota Supercomputing Institute , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Christopher J Cramer
- Department of Chemistry, Chemical Theory Center, and The Minnesota Supercomputing Institute , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Laura Gagliardi
- Department of Chemistry, Chemical Theory Center, and The Minnesota Supercomputing Institute , University of Minnesota , Minneapolis , Minnesota 55455 , United States
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