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Troß J, Arias-Martinez JE, Carter-Fenk K, Cole-Filipiak NC, Schrader P, McCaslin LM, Head-Gordon M, Ramasesha K. Femtosecond Core-Level Spectroscopy Reveals Involvement of Triplet States in the Gas-Phase Photodissociation of Fe(CO) 5. J Am Chem Soc 2024; 146:22711-22723. [PMID: 39092878 DOI: 10.1021/jacs.4c07523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Excitation of iron pentacarbonyl [Fe(CO)5], a prototypical photocatalyst, at 266 nm causes the sequential loss of two CO ligands in the gas phase, creating catalytically active, unsaturated iron carbonyls. Despite numerous studies, major aspects of its ultrafast photochemistry remain unresolved because the early excited-state dynamics have so far eluded spectroscopic observation. This has led to the long-held assumption that ultrafast dissociation of gas-phase Fe(CO)5 proceeds exclusively on the singlet manifold. Herein, we present a combined experimental-theoretical study employing ultrafast extreme ultraviolet transient absorption spectroscopy near the Fe M2,3-edge, which features spectral evolution on 100 fs and 3 ps time scales, alongside high-level electronic structure theory, which enables characterization of the molecular geometries and electronic states involved in the ultrafast photodissociation of Fe(CO)5. We assign the 100 fs evolution to spectroscopic signatures associated with intertwined structural and electronic dynamics on the singlet metal-centered states during the first CO loss and the 3 ps evolution to the competing dissociation of Fe(CO)4 along the lowest singlet and triplet surfaces to form Fe(CO)3. Calculations of transient spectra in both singlet and triplet states as well as spin-orbit coupling constants along key structural pathways provide evidence for intersystem crossing to the triplet ground state of Fe(CO)4. Thus, our work presents the first spectroscopic detection of transient excited states during ultrafast photodissociation of gas-phase Fe(CO)5 and challenges the long-standing assumption that triplet states do not play a role in the ultrafast dynamics.
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Affiliation(s)
- Jan Troß
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Juan E Arias-Martinez
- Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Kevin Carter-Fenk
- Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Neil C Cole-Filipiak
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Paul Schrader
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Laura M McCaslin
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Martin Head-Gordon
- Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Krupa Ramasesha
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
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2
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Munshi MU, Berden G, Oomens J. Infrared Ion Spectroscopic Characterization of the Gaseous [Co(15-crown-5)(H 2O)] 2+ Complex. J Phys Chem A 2023; 127:7256-7263. [PMID: 37595154 PMCID: PMC10476210 DOI: 10.1021/acs.jpca.3c04241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 08/04/2023] [Indexed: 08/20/2023]
Abstract
We report fingerprint infrared multiple-photon dissociation spectra of the gaseous monohydrated coordination complex of cobalt(II) and the macrocycle 1,4,7,10,13-pentaoxacyclopentadecane (or 15-crown-5), [Co(15-crown-5)(H2O)]2+. The metal-ligand complexes are generated using electrospray ionization, and their IR action spectra are recorded in a quadrupole ion trap mass spectrometer using the free-electron laser FELIX. The electronic structure and chelation motif are derived from spectral comparison with computed vibrational spectra obtained at the density functional theory level. We focus here on the gas-phase structure, addressing the question of doublet versus quartet spin multiplicity and the chelation geometry. We conclude that the gas-phase complex adopts a quartet spin state, excluding contributions of doublet species, and that the chelation geometry is pseudo-octahedral with the six oxygen centers of 15-crown-5 and H2O coordinated to the metal ion. We also address the possible presence of higher-energy conformers based on the IR spectral evidence and calculated thermodynamics.
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Affiliation(s)
| | - Giel Berden
- FELIX
Laboratory, Radboud University, Institute
for Molecules and Materials, Toernooiveld 7, 6525
ED Nijmegen, The
Netherlands
| | - Jos Oomens
- FELIX
Laboratory, Radboud University, Institute
for Molecules and Materials, Toernooiveld 7, 6525
ED Nijmegen, The
Netherlands
- University
of Amsterdam, Science
Park 904, 1098XH Amsterdam, The Netherlands
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3
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Sánchez-de-Armas R, Jaber El Lala I, Calzado CJ. How complex-surface interactions modulate the spin transition of Fe(II) SCO complexes supported on metallic surfaces? Phys Chem Chem Phys 2023; 25:21673-21683. [PMID: 37551593 DOI: 10.1039/d3cp02539j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
The deposition of a prototypical spin-crossover [Fe(phen)2(NCS)2] complex on Au(111), Cu(111) and Ag(111) surfaces has been investigated by means of periodic DFT+U calculations, with the aim of understanding how different metallic surfaces affect the spin state switching. Our results show that adsorption is metal- and spin-dependent, with different preferred adsorption sites for the different surfaces and spin states. For the three considered surfaces adsorption energies are larger in the LS state than in the HS one, which increases the transition enthalpy by 58.7 kJ mol-1 for Cu(111), 14.6 kJ mol-1 for Au(111) and 9.6 kJ mol-1 for Ag(111) with respect to the free molecule. There is a clear correlation between this effect and the extent of the complex-surface interaction, which can be established from adsorption energies, surface-complex distances and charge density difference plots as: Cu(111) > Au(111) > Ag(111). Therefore, a stronger interaction with the surface produces a larger energy difference between two spin states, making the spin transition less probable to occur. Finally, our calculations show that it would be possible to probe the spin-state of the deposited molecules from the STM images, in line with the recent experimental results.
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Affiliation(s)
- Rocío Sánchez-de-Armas
- Departamento de Química Física, Universidad de Sevilla, C. Prof. García González, s/n, 41012, Spain.
| | - Iman Jaber El Lala
- Departamento de Química Física, Universidad de Sevilla, C. Prof. García González, s/n, 41012, Spain.
| | - Carmen J Calzado
- Departamento de Química Física, Universidad de Sevilla, C. Prof. García González, s/n, 41012, Spain.
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4
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Joshi S, Roy Chowdhury S, Mishra S. Spin-state energetics and magnetic anisotropy in penta-coordinated Fe(III) complexes with different axial and equatorial ligand environments. Phys Chem Chem Phys 2023. [PMID: 37367302 DOI: 10.1039/d3cp02182c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
The penta-coordinated trigonal-bi-pyramidal (TBP) Fe(III) complex (PMe2Ph)2FeCl3 shows a reduced magnetic anisotropy in its intermediate-spin (IS) state as compared to its methyl-analog (PMe3)2Fe(III)Cl3. In this work, the ligand environment in (PMe2Ph)2FeCl3 is systematically altered by replacing the axial -P with -N and -As, the equatorial -Cl with other halides, and the axial methyl group with an acetyl group. This has resulted in a series of Fe(III) TBP complexes modelled in their IS and high-spin (HS) states. Lighter ligands -N and -F stabilize the complex in the HS state, while the magnetically anisotropic IS state is stabilized by -P and -As at the axial site, and -Cl, -Br, and -I at the equatorial site. Larger magnetic anisotropies appear for complexes with nearly degenerate ground electronic states that are well separated from the higher excited states. This requirement, largely controlled by the d-orbital splitting pattern due to the changing ligand field, is achieved with a certain combination of axial and equatorial ligands, such as -P and -Br, -As and -Br, and -As and -I. In most cases, the acetyl group at the axial site enhances the magnetic anisotropy compared to its methyl counterpart. In contrast, the presence of -I at the equatorial site compromises the uniaxial type of anisotropy of the Fe(III) complex leading to an enhanced rate of quantum tunneling of magnetization.
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Affiliation(s)
- Shalini Joshi
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India.
| | | | - Sabyashachi Mishra
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India.
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5
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Branching mechanism of photoswitching in an Fe(II) polypyridyl complex explained by full singlet-triplet-quintet dynamics. Commun Chem 2023; 6:7. [PMID: 36697805 PMCID: PMC9829715 DOI: 10.1038/s42004-022-00796-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/09/2022] [Indexed: 01/11/2023] Open
Abstract
It has long been known that irradiation with visible light converts Fe(II) polypyridines from their low-spin (singlet) to high-spin (quintet) state, yet mechanistic interpretation of the photorelaxation remains controversial. Herein, we simulate the full singlet-triplet-quintet dynamics of the [Fe(terpy)2]2+ (terpy = 2,2':6',2"-terpyridine) complex in full dimension, in order to clarify the complex photodynamics. Importantly, we report a branching mechanism involving two sequential processes: a dominant 3MLCT→3MC(3T2g)→3MC(3T1g)→5MC, and a minor 3MLCT→3MC(3T2g)→5MC component. (MLCT = metal-to-ligand charge transfer, MC = metal-centered). While the direct 3MLCT→5MC mechanism is considered as a relevant alternative, we show that it could only be operative, and thus lead to competing pathways, in the absence of 3MC states. The quintet state is populated on the sub-picosecond timescale involving non-exponential dynamics and coherent Fe-N breathing oscillations. The results are in agreement with the available time-resolved experimental data on Fe(II) polypyridines, and fully describe the photorelaxation dynamics.
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Nadeem M, Cruddas J, Ruzzi G, Powell BJ. Toward High-Temperature Light-Induced Spin-State Trapping in Spin-Crossover Materials: The Interplay of Collective and Molecular Effects. J Am Chem Soc 2022; 144:9138-9148. [PMID: 35546521 DOI: 10.1021/jacs.2c03202] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Spin-crossover (SCO) materials display many fascinating behaviors including collective phase transitions and spin-state switching controlled by external stimuli, e.g., light and electrical currents. As single-molecule switches, they have been fêted for numerous practical applications, but these remain largely unrealized-partly because of the difficulty of switching these materials at high temperatures. We introduce a semiempirical microscopic model of SCO materials combining crystal field theory with elastic intermolecular interactions. For realistic parameters, this model reproduces the key experimental results including thermally induced phase transitions, light-induced spin-state trapping (LIESST), and reverse-LIESST. Notably, we reproduce and explain the experimentally observed relationship between the critical temperature of the thermal transition, T1/2, and the highest temperature for which the trapped state is stable, TLIESST, and explain why increasing the stiffness of the coordination sphere increases TLIESST. We propose strategies to design SCO materials with higher TLIESST: optimizing the spin-orbit coupling via heavier atoms (particularly in the inner coordination sphere) and minimizing the enthalpy difference between the high-spin (HS) and low-spin (LS) states. However, the most dramatic increases arise from increasing the cooperativity of the spin-state transition by increasing the rigidity of the crystal. Increased crystal rigidity can also stabilize the HS state to low temperatures on thermal cycling yet leave the LS state stable at high temperatures following, for example, reverse-LIESST. We show that such highly cooperative systems offer a realistic route to robust room-temperature switching, demonstrate this in silico, and discuss material design rationale to realize this.
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Affiliation(s)
- M Nadeem
- School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jace Cruddas
- School of Physical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Gian Ruzzi
- School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Benjamin J Powell
- School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland 4072, Australia
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7
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Karmakar S, Chakraborty P, Saha-Dasgupta T. Trend in light-induced excited-state spin trapping in Fe(II)-based spin crossover systems. Phys Chem Chem Phys 2022; 24:10201-10209. [PMID: 35420090 DOI: 10.1039/d2cp00539e] [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
A computational study of the light-induced excited spin-state trapping (LIESST) in a number of Fe(II) spin crossover complexes, coordinated by monodentate, bidentate and multidentate ligands is carried out, with the goal to uncover the trend in the low temperature relaxation rate. A nine order of magnitude change in low temperature relaxation rate is observed among the complexes. The trend is rationalized in terms of the change in metal-ligand covalency, numerically estimated by the crystal orbital Hamiltonian population, thus influencing the back donation or delocalization of the electrons from the low-lying Fe(II)-centered molecular orbital to the empty low-lying ligand-centered π* antibonding molecular orbitals.
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Affiliation(s)
- Shiladitya Karmakar
- Department of Condensed Matter Physics and Materials Science, S. N. Bose National Centre for Basic Sciences, Kolkata 700 106, India.
| | - Pradip Chakraborty
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.
| | - Tanusri Saha-Dasgupta
- Department of Condensed Matter Physics and Materials Science, S. N. Bose National Centre for Basic Sciences, Kolkata 700 106, India.
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8
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Pápai M. Toward Simulation of Fe(II) Low-Spin → High-Spin Photoswitching by Synergistic Spin-Vibronic Dynamics. J Chem Theory Comput 2022; 18:1329-1339. [PMID: 35199532 PMCID: PMC8908767 DOI: 10.1021/acs.jctc.1c01184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
A new theoretical
approach is presented and applied for the simulation
of Fe(II) low-spin (LS, singlet, t2g6eg0) → high-spin (HS, quintet, t2g4eg2) photoswitching dynamics of the octahedral
model complex [Fe(NCH)6]2+. The utilized synergistic
methodology heavily exploits the strengths of complementary electronic
structure and spin-vibronic dynamics methods. Specifically, we perform
3D quantum dynamics (QD) and full-dimensional trajectory surface hopping
(TSH, in conjunction with a linear vibronic coupling model), with
the modes for QD selected by TSH. We follow a hybrid approach which
is based on the application of time-dependent density functional theory
(TD-DFT) excited-state potential energy surfaces (PESs) and multiconfigurational
second-order perturbation theory (CASPT2) spin–orbit couplings
(SOCs). Our method delivers accurate singlet–triplet–quintet
intersystem crossing (ISC) dynamics, as assessed by comparison to
our recent high-level ab initio simulations and related
time-resolved experimental data. Furthermore, we investigate the capability
of our simulations to identify the location of ISCs. Finally, we assess
the approximation of constant SOCs (calculated at the Franck–Condon
geometry), whose validity has central importance for the combination
of TD-DFT PESs and CASPT2 SOCs. This efficient methodology will have
a key role in simulating LS → HS dynamics for more complicated
cases, involving higher density of states and varying electronic character,
as well as the analysis of ultrafast experiments.
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Affiliation(s)
- Mátyás Pápai
- Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary
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9
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Finney BA, Chowdhury SR, Kirkvold C, Vlaisavljevich B. CASPT2 molecular geometries of Fe(II) spin-crossover complexes. Phys Chem Chem Phys 2022; 24:1390-1398. [PMID: 34981806 DOI: 10.1039/d1cp04885f] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Using fully internally contracted (FIC)-CASPT2 analytical gradients, geometry optimizations of spin-crossover complexes are reported. This approach is tested on a series of Fe(II) complexes with different sizes, ranging from 13 to 61 atoms. A combination of active space and basis set choices are employed to investigate their role in determining reliable molecular geometries. The reported strategy demonstrates that a wave function-based level of theory can be used to optimize the geometries of metal complexes in reasonable times and enables one to treat the molecular geometry and electronic structure of the complexes using the same level of theory. For a series of smaller Fe(II) SCO complexes, strong field ligands in the LS state result in geometries with the largest differences between DFT and CASPT2; however, good agreement overall is observed between DFT and CASPT2. For the larger complexes, moderate sized basis sets yield geometries that compare well with DFT and available experimental data. We recommend using the (10e,12o) active space since convergence to a minimum structure was more efficient than with truncated active spaces despite having similar Fe-ligand bond distances.
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Affiliation(s)
- Brian A Finney
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
| | - Sabyasachi Roy Chowdhury
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
| | - Clara Kirkvold
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
| | - Bess Vlaisavljevich
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
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10
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Frešer F, Hostnik G, Tošović J, Bren U. Dependence of the Fe(II)-Gallic Acid Coordination Compound Formation Constant on the pH. Foods 2021; 10:2689. [PMID: 34828967 PMCID: PMC8619179 DOI: 10.3390/foods10112689] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 10/28/2021] [Accepted: 10/31/2021] [Indexed: 11/16/2022] Open
Abstract
One important property of tannins involves their ability to form coordination compounds with metal ions, which is vital for the bioavailability of these ions, as well as for the antibacterial and antioxidative activities of tannins. In this study, the pH dependence of interactions between gallic acid, one of the basic building blocks of tannins, and Fe(II) ions, was investigated using UV/Vis spectroscopy, in conjunction with density functional theory (DFT) calculations. Moreover, two models were developed to explain the processes taking place in the solution. The first model treated the reaction as a simple bimolecular process while the second also considered the protolytic equilibrium, which was proven very successful in discerning the pH dependence of formation constants, and whose assumptions were well supported by DFT calculations. We showed that the two-time deprotonated gallic acid species forms the coordination compound with Fe(II) ions in a 1:1 molar ratio. To gain better insight into the process, the coordination compound formation was also studied using various DFT functionals, which further supported the model results. Furthermore, due to the relatively low sample amounts needed, the methodology developed here will be useful to study compounds that are more difficult to isolate.
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Affiliation(s)
- Franjo Frešer
- Faculty of Chemistry and Chemical Technology, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia; (F.F.); (G.H.); (J.T.)
| | - Gregor Hostnik
- Faculty of Chemistry and Chemical Technology, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia; (F.F.); (G.H.); (J.T.)
| | - Jelena Tošović
- Faculty of Chemistry and Chemical Technology, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia; (F.F.); (G.H.); (J.T.)
| | - Urban Bren
- Faculty of Chemistry and Chemical Technology, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia; (F.F.); (G.H.); (J.T.)
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, SI-6000 Koper, Slovenia
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11
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Kwon HY, Ashley DC, Jakubikova E. Halogenation affects driving forces, reorganization energies and "rocking" motions in strained [Fe(tpy) 2] 2+ complexes. Dalton Trans 2021; 50:14566-14575. [PMID: 34586133 DOI: 10.1039/d1dt02314d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Controlling the energetics of spin crossover (SCO) in Fe(II)-polypyridine complexes is critical for designing new multifunctional materials or tuning the excited-state lifetimes of iron-based photosensitizers. It is well established that the Fe-N "breathing" mode is important for intersystem crossing from the singlet to the quintet state, but this does not preclude other, less obvious, structural distortions from affecting SCO. Previous work has shown that halogenation at the 6 and 6'' positions of tpy (tpy = 2,2';6',2''-terpyridine) in [Fe(tpy)2]2+ dramatically increased the lifetime of the excited MLCT state and also had a large impact on the ground state spin-state energetics. To gain insight into the origins of these effects, we used density functional theory calculations to explore how halogenation impacts spin-state energetics and molecular structure in this system. Based on previous work we focused on the ligand "rocking" motion associated with SCO in [Fe(tpy)2]2+ by constructing one-dimensional potential energy surfaces (PESs) along the tpy rocking angle for various spin states. It was found that halogenation has a clear and predictable impact on ligand rocking and spin-state energetics. The rocking is correlated to numerous other geometrical distortions, all of which likely affect the reorganization energies for spin-state changes. We have quantified trends in reorganization energy and also driving force for various spin-state changes and used them to interpret the experimentally measured excited-state lifetimes.
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Affiliation(s)
- Hyuk-Yong Kwon
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Dr., Raleigh, NC 27695, USA.
| | - Daniel C Ashley
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Dr., Raleigh, NC 27695, USA.
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Dr., Raleigh, NC 27695, USA.
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12
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Palomino CM, Sánchez-de-Armas R, Calzado CJ. Theoretical inspection of the spin-crossover [Fe(tzpy) 2(NCS) 2] complex on Au(100) surface. J Chem Phys 2021; 154:034701. [PMID: 33499621 DOI: 10.1063/5.0036612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We explore the deposition of the spin-crossover [Fe(tzpy)2(NCS)2] complex on the Au(100) surface by means of density functional theory (DFT) based calculations. Two different routes have been employed: low-cost finite cluster-based calculations, where both the Fe complex and the surface are maintained fixed while the molecule approaches the surface; and periodic DFT plane-wave calculations, where the surface is represented by a four-layer slab and both the molecule and surface are relaxed. Our results show that the bridge adsorption site is preferred over the on-top and fourfold hollow ones for both spin states, although they are energetically close. The LS molecule is stabilized by the surface, and the HS-LS energy difference is enhanced by about 15%-25% once deposited. The different Fe ligand field for LS and HS molecules manifests on the composition and energy of the low-lying bands. Our simulated STM images indicate that it is possible to distinguish the spin state of the deposited molecules by tuning the bias voltage of the STM tip. Finally, it should be noted that the use of a reduced size cluster to simulate the Au(100) surface proves to be a low-cost and reliable strategy, providing results in good agreement with those resulting from state-of-the-art periodic calculations for this system.
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Affiliation(s)
- Carlos M Palomino
- Departamento de Química Física, c/Profesor García González, s/n 41012 Sevilla, Spain
| | | | - Carmen J Calzado
- Departamento de Química Física, c/Profesor García González, s/n 41012 Sevilla, Spain
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13
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Abstract
Coordination compounds, characterized by fascinating and tunable electronic properties, are capable of binding easily to proteins, polymers, wires and DNA. Upon irradiation, these molecular systems develop functions finding applications in solar cells, photocatalysis, luminescent and conformational probes, electron transfer triggers and diagnostic or therapeutic tools. The control of these functions is activated by the light wavelength, the metal/ligand cooperation and the environment within the first picoseconds (ps). After a brief summary of the theoretical background, this perspective reviews case studies, from 1st row to 3rd row transition metal complexes, that illustrate how spin-orbit, vibronic coupling and quantum effects drive the photophysics of this class of molecules at the early stage of the photoinduced elementary processes within the fs-ps time scale range.
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Affiliation(s)
- Chantal Daniel
- Laboratoire de Chimie Quantique, Université de Strasbourg, CNRS UMR7177, Institut Le Bel, 4 Rue Blaise Pascal, 67000 Strasbourg, France.
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14
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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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15
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Dey B, Gupta A, Kapurwan S, Konar S. Study of Spin Crossover Property of a Series of X‐OMe‐SalEen (X=6, 5 and 4) Based Fe(III) Complexes. ChemistrySelect 2020. [DOI: 10.1002/slct.202003135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Bijoy Dey
- Department of Chemistry Indian Institute of Science Education and Research Bhopal Bhopal by-pass road Bhauri Bhopal 462066 India
| | - Arindam Gupta
- Department of Chemistry Indian Institute of Science Education and Research Bhopal Bhopal by-pass road Bhauri Bhopal 462066 India
| | - Sandhya Kapurwan
- Department of Chemistry Indian Institute of Science Education and Research Bhopal Bhopal by-pass road Bhauri Bhopal 462066 India
| | - Sanjit Konar
- Department of Chemistry Indian Institute of Science Education and Research Bhopal Bhopal by-pass road Bhauri Bhopal 462066 India
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16
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Iuchi S, Koga N. A model electronic Hamiltonian to describe low-lying d-d and metal-to-ligand charge-transfer excited states of [Fe(bpy) 3 ] 2. J Comput Chem 2020; 42:166-179. [PMID: 33146893 DOI: 10.1002/jcc.26444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 11/10/2022]
Abstract
A simple practical method to compute both d-d and metal-to-ligand charge-transfer (MLCT) excited states of iron(II) polypyridyl complexes is proposed for use in simulation studies. Specifically, a model electronic Hamiltonian developed previously for d-d excited states of [Fe(bpy)3 ]2+ is extended to deal with low-lying MLCT excited states simultaneously by including the MLCT electronic configurations into the basis functions of the model Hamiltonian. As a first attempt, parameters in the model Hamiltonian matrix elements are determined by using density functional theory (DFT) and time-dependent (TD-)DFT calculation results as benchmarks. To examine the performance of the model Hamiltonian, the potential energy curves along the interpolation between the lowest singlet and quintet state structures are compared to those from the (TD-)DFT calculations and to those from CASPT2 calculations in literature. The electronic absorption spectrum computed through molecular dynamics simulation is compared to the experimental spectrum. The spin-orbit couplings at the ground state structure are also compared to those from wavefunction-based ab initio electronic structure calculations. The results indicate that the constructed model Hamiltonian provides reasonable information on both the low-lying d-d and MLCT excited states of [Fe(bpy)3 ]2+ .
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Affiliation(s)
- Satoru Iuchi
- Graduate School of Informatics, Nagoya University, Nagoya, Japan
| | - Nobuaki Koga
- Graduate School of Informatics, Nagoya University, Nagoya, Japan
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17
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Sárosiné Szemes D, Keszthelyi T, Papp M, Varga L, Vankó G. Quantum-chemistry-aided ligand engineering for potential molecular switches: changing barriers to tune excited state lifetimes. Chem Commun (Camb) 2020; 56:11831-11834. [PMID: 33021253 DOI: 10.1039/d0cc04467a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Substitution of terpyridine at the 4' position with electron withdrawing and donating groups is used to tune the quintet lifetime of its iron(ii) complex. DFT calculations suggest that the energy barrier between the quintet and singlet states can be altered significantly upon substitution, inducing a large variation of the lifetime of the photoexcited quintet state. This prediction was experimentally verified by transient optical absorption spectroscopy and good agreement with the trend expected from the calculations was found. This demonstrates that the potential energy landscape can indeed be rationally tailored by relevant modifications based on DFT predictions. This result should pave the way to advancing efficient theory-based ligand engineering of functional molecules to a wide range of applications.
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18
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Dey B, Mondal A, Konar S. Effect of Ligand Field Strength on the Spin Crossover Behaviour in 5‐X‐SalEen (X=Me, Br and OMe) Based Fe(III) Complexes. Chem Asian J 2020; 15:1709-1721. [DOI: 10.1002/asia.202000156] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/14/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Bijoy Dey
- Department of ChemistryIndian Institute of Science Education and Research Bhopal Bhopal bypass road, Bhauri Bhopal 462066, MP India
| | - Arpan Mondal
- Department of ChemistryIndian Institute of Science Education and Research Bhopal Bhopal bypass road, Bhauri Bhopal 462066, MP India
| | - Sanjit Konar
- Department of ChemistryIndian Institute of Science Education and Research Bhopal Bhopal bypass road, Bhauri Bhopal 462066, MP India
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19
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Francés‐Monerris A, Gros PC, Assfeld X, Monari A, Pastore M. Toward Luminescent Iron Complexes: Unravelling the Photophysics by Computing Potential Energy Surfaces. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900100] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Antonio Francés‐Monerris
- Laboratoire de Physique et Chimie Théoriques (LPCT)Université de Lorraine, CNRS 54000 Nancy France
| | - Philippe C. Gros
- Laboratoire Lorrain de Chimie Moléculaire (L2CM)Université de Lorraine, CNRS 54000 Nancy France
| | - Xavier Assfeld
- Laboratoire de Physique et Chimie Théoriques (LPCT)Université de Lorraine, CNRS 54000 Nancy France
| | - Antonio Monari
- Laboratoire de Physique et Chimie Théoriques (LPCT)Université de Lorraine, CNRS 54000 Nancy France
| | - Mariachiara Pastore
- Laboratoire de Physique et Chimie Théoriques (LPCT)Université de Lorraine, CNRS 54000 Nancy France
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20
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Photophysical properties of bichromophoric Fe(II) complexes bearing an aromatic electron acceptor. Theor Chem Acc 2019. [DOI: 10.1007/s00214-019-2471-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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21
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Radoń M. Benchmarking quantum chemistry methods for spin-state energetics of iron complexes against quantitative experimental data. Phys Chem Chem Phys 2019; 21:4854-4870. [PMID: 30778468 DOI: 10.1039/c9cp00105k] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The accuracy of relative spin-state energetics predicted by selected quantum chemistry methods: coupled cluster theory at the CCSD(T) level, multiconfigurational perturbation theory (CASPT2, NEVPT2), multireference configuration interaction at the MRCISD+Q level, and a number of DFT methods, is quantitatively evaluated by comparison with the experimental data of four octahedral iron complexes. The available experimental data, either spin-forbidden transition energies or spin crossover enthalpies, are corrected for relevant environmental effects in order to derive the quantitative benchmark set of iron spin-state energetics. Comparison of theory predictions with the resulting reference data: (1) validates the high accuracy of the CCSD(T) method, particularly when based on Kohn-Sham orbitals, giving the maximum error below 2 kcal mol-1 and the mean absolute error (MAE) below 1 kcal mol-1; (2) corroborates the tendency of CASPT2 to systematically overstabilize higher-spin states by up to 5.5 kcal mol-1; (3) confirms that the latter problem is partly remedied by the recently proposed CASPT2/CC approach [Phung et al., J. Chem. Theory Comput., 2018, 14, 2446-2455]; (4) demonstrates that NEVPT2 performs worse than CASPT2, by giving errors up to 7 kcal mol-1; (5) shows that the accuracy of MRCISD+Q spin-state energetics strongly depends on the size-consistency correction: the Davidson-Silver and Pople corrections perform best (MAE < 3 kcal mol-1), whereas the standard Davidson correction is not recommended (MAE of 7 kcal mol-1). Only a few DFT methods (including the best performing ones identified in this study: B2PLYP-D3 and OPBE) are able to provide a balanced description of the spin-state energetics for all four studied iron complexes simultaneously, corroborating the non-universality problem of approximate density functionals.
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Affiliation(s)
- Mariusz Radoń
- Faculty of Chemistry, Jagiellonian University in Krakow, ul. Gronostajowa 2, 30-387 Kraków, Poland.
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22
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Khakhulin D, Lawson Daku LM, Leshchev D, Newby GE, Jarenmark M, Bressler C, Wulff M, Canton SE. Visualizing the coordination-spheres of photoexcited transition metal complexes with ultrafast hard X-rays. Phys Chem Chem Phys 2019; 21:9277-9284. [DOI: 10.1039/c9cp01263j] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The concept of coordination sphere (CS) is central to the rational development of hierarchical molecular assemblies in modern chemistry.
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Affiliation(s)
| | - L. M. Lawson Daku
- Département de Chimie Physique
- Université de Genève
- CH-1211 Genève 4
- Switzerland
| | - D. Leshchev
- European Synchrotron Radiation Facility (ESRF)
- 38000 Grenoble Cedex 9
- France
| | - G. E. Newby
- European Synchrotron Radiation Facility (ESRF)
- 38000 Grenoble Cedex 9
- France
| | - M. Jarenmark
- Department of Geology
- Lund University
- 223 62 Lund
- Sweden
- Lund University
| | | | - M. Wulff
- European Synchrotron Radiation Facility (ESRF)
- 38000 Grenoble Cedex 9
- France
| | - S. E. Canton
- ELI-ALPS
- ELI-HU Non-Profit Ltd
- Szeged 6720
- Hungary
- Attosecond Science Group
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23
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Abedi M, Levi G, Zederkof DB, Henriksen NE, Pápai M, Møller KB. Excited-state solvation structure of transition metal complexes from molecular dynamics simulations and assessment of partial atomic charge methods. Phys Chem Chem Phys 2019; 21:4082-4095. [DOI: 10.1039/c8cp06567e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Excited-state solvation structure (radial distribution function) of transition metal complexes by classical and mixed quantum-classical (QM/MM) molecular dynamics simulations.
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Affiliation(s)
- Mostafa Abedi
- Department of Chemistry
- Technical University of Denmark
- 2800 Kongens Lyngby
- Denmark
| | - Gianluca Levi
- Department of Chemistry
- Technical University of Denmark
- 2800 Kongens Lyngby
- Denmark
| | - Diana B. Zederkof
- Department of Physics
- Technical University of Denmark
- 2800 Kongens Lyngby
- Denmark
| | - Niels E. Henriksen
- Department of Chemistry
- Technical University of Denmark
- 2800 Kongens Lyngby
- Denmark
| | - Mátyás Pápai
- Department of Chemistry
- Technical University of Denmark
- 2800 Kongens Lyngby
- Denmark
- Wigner Research Center for Physics
| | - Klaus B. Møller
- Department of Chemistry
- Technical University of Denmark
- 2800 Kongens Lyngby
- Denmark
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24
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Sugaya T, Fujihara T, Naka T, Furubayashi T, Matsushita A, Isago H, Nagasawa A. Observation of the First Spin Crossover in an Iron(II) Complex with an S 6 Coordination Environment: Tris[bis(N,N-diethylamino)carbeniumdithiocarboxylato]iron(II) Hexafluorophosphate. Chemistry 2018; 24:17955-17963. [PMID: 30311982 DOI: 10.1002/chem.201803330] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 10/01/2018] [Indexed: 11/10/2022]
Abstract
For the first time, the spin-crossover (SCO) phenomenon has been observed in an FeII -S6 system in a tris(chelate)-type iron(II) complex with a zwitterionic sulfur donor bidentate, bis(N,N-diethylamino)carbeniumdithiocarboxylate (EtL), [FeII (EtL)3 ](PF6 )2 (1), as synthesized by the reaction of a precursor complex [FeII (CH3 CN)6 ](PF6 )2 with EtL. In the solid state, the high-spin (HS) d6 state at ambient temperature and the low-spin (LS) d6 state at temperatures lower than approximately 240 K were evidenced by magnetic measurements with SQUID and Mössbauer spectra in the temperature range 4-290 K. X-ray analyses of the crystals at various temperatures disclosed that the distorted trigonal prismatic coordination environments essentially do not change; however, contraction of Fe-S distances by approximately 10 % (0.22 Å), ordering of alkyl groups in EtL and PF6 - counteranions, and formation of significant intermolecular S⋅⋅⋅S interactions between adjacent molecules (average distances of 3.59 Å) take place during the transition from the HS to the LS state. A large decrease in the volume of the formula unit (78.1 Å3 ) might be responsible for the large activation barrier, thereby resulting in a slow phase transition upon cooling.
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Affiliation(s)
- Tomoaki Sugaya
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan.,Education Center, Faculty of Engineering, Chiba Institute of Technology, 2-1-1 Shibazono, Narashino-shi, Chiba, 275-0023, Japan
| | - Takashi Fujihara
- Comprehensive Analysis Center for Science, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Takashi Naka
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba-shi, Ibaraki, 305-0047, Japan
| | - Takao Furubayashi
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba-shi, Ibaraki, 305-0047, Japan
| | - Akiyuki Matsushita
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba-shi, Ibaraki, 305-0047, Japan
| | - Hiroaki Isago
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba-shi, Ibaraki, 305-0047, Japan
| | - Akira Nagasawa
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
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25
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Sousa C, Alías M, Domingo A, de Graaf C. Deactivation of Excited States in Transition-Metal Complexes: Insight from Computational Chemistry. Chemistry 2018; 25:1152-1164. [DOI: 10.1002/chem.201801990] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Carmen Sousa
- Departament de Química Física and Institut de Química, Teòrica i Computacional; Universitat de Barcelona; C/ Martí i Franquès 1 08028 Barcelona Catalunya Spain
| | - Marc Alías
- Departament de Química Física i Inorgànica; Universitat Rovira i Virgili; Marcel⋅lí Domingo 1 43007 Tarragona Catalunya Spain
| | - Alex Domingo
- Departament de Química Física i Inorgànica; Universitat Rovira i Virgili; Marcel⋅lí Domingo 1 43007 Tarragona Catalunya Spain
| | - Coen de Graaf
- Departament de Química Física i Inorgànica; Universitat Rovira i Virgili; Marcel⋅lí Domingo 1 43007 Tarragona Catalunya Spain
- ICREA; Pg. Lluis Companys 23 08010 Barcelona Catalunya Spain
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26
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Zhang Y, Bennett K, Mukamel S. Monitoring Ultrafast Spin Crossover Intermediates in an Iron(II) Complex by Broad Band Stimulated X-ray Raman Spectroscopy. J Phys Chem A 2018; 122:6524-6531. [PMID: 29944375 DOI: 10.1021/acs.jpca.8b01762] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photoinduced spin crossover dynamics of transition metal complexes is of fundamental scientific importance and is used for sensor device applications and solar energy harvesting. Current X-ray and optical spectroscopy experiments for [FeII(bpy)3], an archetypal earth-abundant metal complex, show conflicting spin dynamics. We have simulated the broad band transient X-ray absorption and hybrid (broad + narrow band) X-ray stimulated Raman signals at the N and Fe K-edges of the key excited state intermediates involved in the spin crossover process of this complex. We find that these signals are much more sensitive to electron and spin populations than transition absorption and may be useful in the design of photovoltaic and artificial photosynthetic systems.
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Affiliation(s)
- Yu Zhang
- Department of Chemistry , University of California , Irvine , California 92697 , United States
| | - Kochise Bennett
- Department of Chemistry , University of California , Irvine , California 92697 , United States
| | - Shaul Mukamel
- Department of Chemistry , University of California , Irvine , California 92697 , United States
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27
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Francés-Monerris A, Magra K, Darari M, Cebrián C, Beley M, Domenichini E, Haacke S, Pastore M, Assfeld X, Gros PC, Monari A. Synthesis and Computational Study of a Pyridylcarbene Fe(II) Complex: Unexpected Effects of fac/ mer Isomerism in Metal-to-Ligand Triplet Potential Energy Surfaces. Inorg Chem 2018; 57:10431-10441. [PMID: 30063338 DOI: 10.1021/acs.inorgchem.8b01695] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The synthesis and the steady-state absorption spectrum of a new pyridine-imidazolylidene Fe(II) complex (Fe-NHC) are presented. A detailed mechanism of the triplet metal-to-ligand charge-transfer states decay is provided on the basis of minimum energy path (MEP) calculations used to connect the lowest-lying singlet, triplet, and quintet state minima. The competition between the different decay pathways involved in the photoresponse is assessed by analyzing the shapes of the obtained potential energy surfaces. A qualitative difference between facial ( fac) and meridional ( mer) isomers' potential energy surface (PES) topologies is evidenced for the first time in iron-based complexes. Indeed, the mer complex shows a steeper triplet path toward the corresponding 3MC minimum, which lies at a lower energy as compared to the fac isomer, thus pointing to a faster triplet decay of the former. Furthermore, while a major role of the metal-centered quintet state population from the triplet 3MC region is excluded, we identify the enlargement of iron-nitrogen bonds as the main normal modes driving the excited-state decay.
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Affiliation(s)
| | - Kevin Magra
- Université de Lorraine , CNRS, L2CM , F57000 Metz , France
| | - Mohamed Darari
- Université de Lorraine , CNRS, L2CM , F54000 Nancy , France
| | | | - Marc Beley
- Université de Lorraine , CNRS, L2CM , F57000 Metz , France
| | | | - Stefan Haacke
- Université de Strasbourg-CNRS , UMR 7504 IPCMS , 67034 Strasbourg , France
| | | | - Xavier Assfeld
- Université de Lorraine , CNRS, LPCT , F54000 Nancy , France
| | | | - Antonio Monari
- Université de Lorraine , CNRS, LPCT , F54000 Nancy , France
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28
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Naim A, Bouhadja Y, Cortijo M, Duverger-Nédellec E, Flack HD, Freysz E, Guionneau P, Iazzolino A, Ould Hamouda A, Rosa P, Stefańczyk O, Valentín-Pérez Á, Zeggar M. Design and Study of Structural Linear and Nonlinear Optical Properties of Chiral [Fe(phen)3]2+ Complexes. Inorg Chem 2018; 57:14501-14512. [DOI: 10.1021/acs.inorgchem.8b01089] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Ahmad Naim
- ICMCB, CNRS, Université de Bordeaux, UMR 5026, F-33600 Pessac, France
| | - Yacine Bouhadja
- Department of Chemistry, University of Annaba, BP 12-23200 Sidi-Ammar, Algérie
| | - Miguel Cortijo
- ICMCB, CNRS, Université de Bordeaux, UMR 5026, F-33600 Pessac, France
- CRPP, CNRS, Université de Bordeaux, UMR 5031, F-33600 Pessac, France
| | | | - Howard D. Flack
- Chimie Minérale, Analytique et Appliquée, Sciences II, Université de Genève, 30, Quai Ernest-Ansermet CH-1211 Geneva Switzerland
| | - Eric Freysz
- LOMA, UMR CNRS 5798, 351 Cours de la Libération, FR-33405 Talence Cedex, France
| | | | - Antonio Iazzolino
- LOMA, UMR CNRS 5798, 351 Cours de la Libération, FR-33405 Talence Cedex, France
| | - Amine Ould Hamouda
- LOMA, UMR CNRS 5798, 351 Cours de la Libération, FR-33405 Talence Cedex, France
| | - Patrick Rosa
- ICMCB, CNRS, Université de Bordeaux, UMR 5026, F-33600 Pessac, France
| | - Olaf Stefańczyk
- ICMCB, CNRS, Université de Bordeaux, UMR 5026, F-33600 Pessac, France
| | - Ángela Valentín-Pérez
- ICMCB, CNRS, Université de Bordeaux, UMR 5026, F-33600 Pessac, France
- CRPP, CNRS, Université de Bordeaux, UMR 5031, F-33600 Pessac, France
| | - Mehdi Zeggar
- ICMCB, CNRS, Université de Bordeaux, UMR 5026, F-33600 Pessac, France
- Department of Chemistry, University of Annaba, BP 12-23200 Sidi-Ammar, Algérie
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29
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Ashley DC, Jakubikova E. Ray-Dutt and Bailar Twists in Fe(II)-Tris(2,2′-bipyridine): Spin States, Sterics, and Fe–N Bond Strengths. Inorg Chem 2018; 57:5585-5596. [DOI: 10.1021/acs.inorgchem.8b00560] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Daniel C. Ashley
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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30
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Penfold TJ, Gindensperger E, Daniel C, Marian CM. Spin-Vibronic Mechanism for Intersystem Crossing. Chem Rev 2018; 118:6975-7025. [DOI: 10.1021/acs.chemrev.7b00617] [Citation(s) in RCA: 401] [Impact Index Per Article: 66.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Thomas J. Penfold
- Chemistry - School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon-Tyne NE1 7RU, United Kingdom
| | - Etienne Gindensperger
- Laboratoire de Chimie Quantique, Institut de Chimie UMR-7177, CNRS - Université de Strasbourg, 1 Rue Blaise Pascal 67008 Strasbourg, France
| | - Chantal Daniel
- Laboratoire de Chimie Quantique, Institut de Chimie UMR-7177, CNRS - Université de Strasbourg, 1 Rue Blaise Pascal 67008 Strasbourg, France
| | - Christel M. Marian
- Institut für Theoretische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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31
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Leshchev D, Harlang TCB, Fredin LA, Khakhulin D, Liu Y, Biasin E, Laursen MG, Newby GE, Haldrup K, Nielsen MM, Wärnmark K, Sundström V, Persson P, Kjær KS, Wulff M. Tracking the picosecond deactivation dynamics of a photoexcited iron carbene complex by time-resolved X-ray scattering. Chem Sci 2018; 9:405-414. [PMID: 29629111 PMCID: PMC5868308 DOI: 10.1039/c7sc02815f] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 10/30/2017] [Indexed: 12/14/2022] Open
Abstract
Recent years have seen the development of new iron-centered N-heterocyclic carbene (NHC) complexes for solar energy applications. Compared to typical ligand systems, the NHC ligands provide Fe complexes with longer-lived metal-to-ligand charge transfer (MLCT) states. This increased lifetime is ascribed to strong ligand field splitting provided by the NHC ligands that raises the energy levels of the metal centered (MC) states and therefore reduces the deactivation efficiency of MLCT states. Among currently known NHC systems, [Fe(btbip)2]2+ (btbip = 2,6-bis(3-tert-butyl-imidazol-1-ylidene)pyridine) is a unique complex as it exhibits a short-lived MC state with a lifetime on the scale of a few hundreds of picoseconds. Hence, this complex allows for a detailed investigation, using 100 ps X-ray pulses from a synchrotron, of strong ligand field effects on the intermediate MC state in an NHC complex. Here, we use time-resolved wide angle X-ray scattering (TRWAXS) aided by density functional theory (DFT) to investigate the molecular structure, energetics and lifetime of the high-energy MC state in the Fe-NHC complex [Fe(btbip)2]2+ after excitation to the MLCT manifold. We identify it as a 260 ps metal-centered quintet (5MC) state, and we refine the molecular structure of the excited-state complex verifying the DFT results. Using information about the hydrodynamic state of the solvent, we also determine, for the first time, the energy of the 5MC state as 0.75 ± 0.15 eV. Our results demonstrate that due to the increased ligand field strength caused by NHC ligands, upon transition from the ground state to the 5MC state, the metal to ligand bonds extend by unusually large values: by 0.29 Å in the axial and 0.21 Å in the equatorial direction. These results imply that the transition in the photochemical properties from typical Fe complexes to novel NHC compounds is manifested not only in the destabilization of the MC states, but also in structural distortion of these states.
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Affiliation(s)
- Denis Leshchev
- European Synchrotron Radiation Facility , 71 Avenue des Martyrs , 38000 Grenoble , France .
| | - Tobias C B Harlang
- Department of Chemical Physics , Lund University , P. O. Box 12 4 , 22100 Lund , Sweden
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Lisa A Fredin
- Theoretical Chemistry Division , Lund University , P. O. Box 124 , 22100 Lund , Sweden
| | | | - Yizhu Liu
- Centre for Analysis and Synthesis , Department of Chemistry , Lund University , P. O. Box 12 4 , Lund 22100 , Sweden
| | - Elisa Biasin
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Mads G Laursen
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Gemma E Newby
- European Synchrotron Radiation Facility , 71 Avenue des Martyrs , 38000 Grenoble , France .
| | - Kristoffer Haldrup
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Martin M Nielsen
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis , Department of Chemistry , Lund University , P. O. Box 12 4 , Lund 22100 , Sweden
| | - Villy Sundström
- Department of Chemical Physics , Lund University , P. O. Box 12 4 , 22100 Lund , Sweden
| | - Petter Persson
- Theoretical Chemistry Division , Lund University , P. O. Box 124 , 22100 Lund , Sweden
| | - Kasper S Kjær
- Department of Chemical Physics , Lund University , P. O. Box 12 4 , 22100 Lund , Sweden
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Michael Wulff
- European Synchrotron Radiation Facility , 71 Avenue des Martyrs , 38000 Grenoble , France .
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32
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Shirani H, Sabzyan H. Computational Spectroscopic Characterization of a Bistable Binuclear Complex [(CO)2(benzoate)FeII/III(terephthalate)CoIII/II(benzoate)(CO)2]+. Aust J Chem 2018. [DOI: 10.1071/ch18044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Electric dipole moments, polarizabilities, and IR, Raman, optical rotatory dispersion, and electronic and vibrational circular dichroism spectra of the four cis–trans isomers of the proposed [(CO)2(benzoate)FeII/III(terephthalate)CoIII/II(benzoate)(CO)2]+ binuclear complex, having bistablity due to intramolecular charge transfer (IMCT), is investigated using the time-dependent density functional theory ((TD)DFT) B3LYP/6–31G(d,p)[LanL2DZ] method. Results show that the two FeII–CoIII and FeIII–CoII IMCT states of this binuclear complex have distinctly different spectroscopic, optical, and electric response properties, and are sensitive to the cis–trans arrangement of the ligands around the two metallic centres. Furthermore, intrinsic reaction coordinates inter-connecting the two IMCT states are identified using the Duschinsky matrix method. Only one or two of the normal coordinates remain almost (above 80 %) intact during the IMCT reaction which denotes global changes in the bonding strengths and potential energy hypersurface of this bistable binuclear complex. Analysis of the calculated spin densities characterizes the IMCT transition state structures of the trans–trans, cis–cis, and trans–cis isomers as early, early, and late transition states, respectively.
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33
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Ashley DC, Jakubikova E. Ironing out the photochemical and spin-crossover behavior of Fe(II) coordination compounds with computational chemistry. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2017.02.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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34
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Fredin LA, Persson P. Computational characterization of competing energy and electron transfer states in bimetallic donor-acceptor systems for photocatalytic conversion. J Chem Phys 2016; 145:104310. [PMID: 27634263 PMCID: PMC5181788 DOI: 10.1063/1.4962254] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The rapidly growing interest in photocatalytic systems for direct solar fuel production such as hydrogen generation from water splitting is grounded in the unique opportunity to achieve charge separation in molecular systems provided by electron transfer processes. In general, both photoinduced and catalytic processes involve complicated dynamics that depend on both structural and electronic effects. Here the excited state landscape of metal centered light harvester-catalyst pairs is explored using density functional theory calculations. In weakly bound systems, the interplay between structural and electronic factors involved can be constructed from the various mononuclear relaxed excited states. For this study, supramolecular states of electron transfer and excitation energy transfer character have been constructed from constituent full optimizations of multiple charge/spin states for a set of three Ru-based light harvesters and nine transition metal catalysts (based on Ru, Rh, Re, Pd, and Co) in terms of energy, structure, and electronic properties. The complete set of combined charge-spin states for each donor-acceptor system provides information about the competition of excited state energy transfer states with the catalytically active electron transfer states, enabling the identification of the most promising candidates for photocatalytic applications from this perspective.
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Affiliation(s)
- Lisa A. Fredin
- Chemical Informatics Research Group, Chemical Sciences Division, Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Mailstop 8320, Gaithersburg, MD
| | - Petter Persson
- Chemistry Department, Theoretical Chemistry Division, Lund University, Box 124, SE-22100 Lund, Sweden
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35
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Fumanal M, Wagner LK, Sanvito S, Droghetti A. Diffusion Monte Carlo Perspective on the Spin-State Energetics of [Fe(NCH)6](2.). J Chem Theory Comput 2016; 12:4233-41. [PMID: 27500854 DOI: 10.1021/acs.jctc.6b00332] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The energy difference between the high spin and the low spin state of the model compound [Fe(NCH)6](2+) is investigated by means of Diffusion Monte Carlo (DMC), where special attention is dedicated to analyzing the effect of the fix node approximation on the accuracy of the results. For this purpose, we compare several Slater-Jastrow and multireference Slater-Jastrow trial wave functions. We found that a Slater-Jastrow trial wave function constructed with the generalized Kohn-Sham orbitals from hybrid DFT represents the optimal choice. This is understood by observing that hybrid functionals account for the subtle balance between exchange and correlation effects and the respective orbitals accurately describe the ligand-metal hybridization as well as the charge reorganization accompanying the spin transition. Finally the DMC results are compared with those obtained by Hartree-Fock, DFT, CASSCF, and CASPT2. While there is no clear reference value for the high spin-low spin energy difference, DMC and high level CCSD(T) calculations agree within around 0.3 eV.
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Affiliation(s)
- Maria Fumanal
- Institut de Chimie UMR7177 CNRS-Université de Strasbourg , 1 Rue Blaise Pascal BP 296/R8, F-67007 Strasbourg, France.,Departament de Química Física and IQTCUB, Facultat de Química, Universitat de Barcelona , Av. Diagonal 645, 08028 Barcelona, Spain
| | - Lucas K Wagner
- Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Stefano Sanvito
- School of Physics, AMBER and CRANN Institute, Trinity College , Dublin 2, Ireland
| | - Andrea Droghetti
- School of Physics, AMBER and CRANN Institute, Trinity College , Dublin 2, Ireland.,Nano-Bio Spectroscopy Group and European Theoretical Spectroscopy Facility (ETSF), Universidad del Pais Vasco CFM CSIC-UPV/EHU-MPC and DIPC , Av.Tolosa 72, 20018 San Sebastian, Spain
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36
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Zhang W, Kjær KS, Alonso-Mori R, Bergmann U, Chollet M, Fredin LA, Hadt RG, Hartsock RW, Harlang T, Kroll T, Kubiček K, Lemke HT, Liang HW, Liu Y, Nielsen MM, Persson P, Robinson JS, Solomon EI, Sun Z, Sokaras D, van Driel TB, Weng TC, Zhu D, Wärnmark K, Sundström V, Gaffney KJ. Manipulating charge transfer excited state relaxation and spin crossover in iron coordination complexes with ligand substitution. Chem Sci 2016; 8:515-523. [PMID: 28451198 PMCID: PMC5341207 DOI: 10.1039/c6sc03070j] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 08/24/2016] [Indexed: 12/11/2022] Open
Abstract
Optical and X-ray free-electron laser measurements reveal ligand substitution in an Fe(ii)-centered complex extends its MLCT lifetime.
Developing light-harvesting and photocatalytic molecules made with iron could provide a cost effective, scalable, and environmentally benign path for solar energy conversion. To date these developments have been limited by the sub-picosecond metal-to-ligand charge transfer (MLCT) electronic excited state lifetime of iron based complexes due to spin crossover – the extremely fast intersystem crossing and internal conversion to high spin metal-centered excited states. We revitalize a 30 year old synthetic strategy for extending the MLCT excited state lifetimes of iron complexes by making mixed ligand iron complexes with four cyanide (CN–) ligands and one 2,2′-bipyridine (bpy) ligand. This enables MLCT excited state and metal-centered excited state energies to be manipulated with partial independence and provides a path to suppressing spin crossover. We have combined X-ray Free-Electron Laser (XFEL) Kβ hard X-ray fluorescence spectroscopy with femtosecond time-resolved UV-visible absorption spectroscopy to characterize the electronic excited state dynamics initiated by MLCT excitation of [Fe(CN)4(bpy)]2–. The two experimental techniques are highly complementary; the time-resolved UV-visible measurement probes allowed electronic transitions between valence states making it sensitive to ligand-centered electronic states such as MLCT states, whereas the Kβ fluorescence spectroscopy provides a sensitive measure of changes in the Fe spin state characteristic of metal-centered excited states. We conclude that the MLCT excited state of [Fe(CN)4(bpy)]2– decays with roughly a 20 ps lifetime without undergoing spin crossover, exceeding the MLCT excited state lifetime of [Fe(2,2′-bipyridine)3]2+ by more than two orders of magnitude.
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Affiliation(s)
- Wenkai Zhang
- PULSE Institute , SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , USA . ;
| | - Kasper S Kjær
- PULSE Institute , SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , USA . ; .,Department of Chemical Physics , Lund University , P.O. Box 12 4 , 22100 Lund , Sweden.,Centre for Molecular Movies , Department of Physics , Technical University of Denmark , DK-2800 , Lyngby , Denmark
| | - Roberto Alonso-Mori
- LCLS , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Uwe Bergmann
- PULSE Institute , SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , USA . ; .,LCLS , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Matthieu Chollet
- LCLS , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Lisa A Fredin
- Theoretical Chemistry Division , Lund University , P.O. Box 124 , 22100 Lund , Sweden
| | - Ryan G Hadt
- Department of Chemistry , Stanford University , Stanford , California 94305 , USA
| | - Robert W Hartsock
- PULSE Institute , SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , USA . ; .,Department of Chemistry , Stanford University , Stanford , California 94305 , USA
| | - Tobias Harlang
- Department of Chemical Physics , Lund University , P.O. Box 12 4 , 22100 Lund , Sweden
| | - Thomas Kroll
- LCLS , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA.,Department of Chemistry , Stanford University , Stanford , California 94305 , USA
| | - Katharina Kubiček
- Max Planck Institute for Biophysical Chemistry , 37077 , Göttingen , Germany
| | - Henrik T Lemke
- LCLS , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Huiyang W Liang
- PULSE Institute , SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , USA . ; .,LCLS , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Yizhu Liu
- Department of Chemical Physics , Lund University , P.O. Box 12 4 , 22100 Lund , Sweden
| | - Martin M Nielsen
- Centre for Molecular Movies , Department of Physics , Technical University of Denmark , DK-2800 , Lyngby , Denmark
| | - Petter Persson
- Theoretical Chemistry Division , Lund University , P.O. Box 124 , 22100 Lund , Sweden
| | - Joseph S Robinson
- LCLS , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Edward I Solomon
- LCLS , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA.,Department of Chemistry , Stanford University , Stanford , California 94305 , USA
| | - Zheng Sun
- PULSE Institute , SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , USA . ;
| | - Dimosthenis Sokaras
- SSRL , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Tim B van Driel
- Centre for Molecular Movies , Department of Physics , Technical University of Denmark , DK-2800 , Lyngby , Denmark
| | - Tsu-Chien Weng
- SSRL , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Diling Zhu
- LCLS , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis , Department of Chemistry , Lund University , P.O. Box 124 , 22100 Lund , Sweden
| | - Villy Sundström
- Department of Chemical Physics , Lund University , P.O. Box 12 4 , 22100 Lund , Sweden
| | - Kelly J Gaffney
- PULSE Institute , SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , USA . ;
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37
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Liu Y, Persson P, Sundström V, Wärnmark K. Fe N-Heterocyclic Carbene Complexes as Promising Photosensitizers. Acc Chem Res 2016; 49:1477-85. [PMID: 27455191 DOI: 10.1021/acs.accounts.6b00186] [Citation(s) in RCA: 162] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The photophysics and photochemistry of transition metal complexes (TMCs) has long been a hot field of interdisciplinary research. Rich metal-based redox processes, together with a high variety in electronic configurations and excited-state dynamics, have rendered TMCs excellent candidates for interconversion between light, chemical, and electrical energies in intramolecular, supramolecular, and interfacial arrangements. In specific applications such as photocatalytic organic synthesis, photoelectrochemical cells, and light-driven supramolecular motors, light absorption by a TMC-based photosensitizer and subsequent excited-state energy or electron transfer constitute essential steps. In this context, TMCs based on rare and expensive metals, such as ruthenium and iridium, are frequently employed as photosensitizers, which is obviously not ideal for large-scale implementation. In the search for abundant and environmentally benign solutions, six-coordinate Fe(II) complexes (Fe(II)L6) have been widely considered as highly desirable alternatives. However, not much success has been achieved due to the extremely short-lived triplet metal-to-ligand charge transfer ((3)MLCT) excited state that is deactivated by low-lying metal-centered (MC) states on a 100 fs time scale. A fundamental strategy to design useful Fe-based photosensitizers is thus to destabilize the MC states relative to the (3)MLCT state by increasing the ligand field strength, with special focus on making eg σ* orbitals on the Fe center energetically less accessible. Previous efforts to directly transplant successful strategies from Ru(II)L6 complexes unfortunately met with limited success in this regard, despite their close chemical kinship. In this Account, we summarize recent promising results from our and other groups in utilizing strongly σ-donating N-heterocyclic carbene (NHC) ligands to make strong-field Fe(II)L6 complexes with significantly extended (3)MLCT lifetimes. Already some of the first homoleptic bis(tridentate) complexes incorporating (CNHC^Npyridine^CNHC)-type ligands gratifyingly resulted in extension of the (3)MLCT lifetime by more than 2 orders of magnitude compared to the parental [Fe(tpy)2](2+) (tpy = 2,2':6',2″-terpyridine) complex. Quantum chemical (QC) studies also revealed that the (3)MC instead of the (5)MC state likely dictates the deactivation of the (3)MLCT state, a behavior distinct from traditional Fe(II)L6 complexes but rather resembling Ru analogues. A heteroleptic Fe(II) NHC complex featuring mesoionic bis(1,2,3-triazol-5-ylidene) (btz) ligands also delivered a 100-fold elongation of the (3)MLCT lifetime relative to its parental [Fe(bpy)3](2+) (bpy = 2,2'-bipyridine) complex. Again, a Ru-like deactivation mechanism of the (3)MLCT state was indicated by QC studies. With a COOH-functionalized homoleptic complex, a record (3)MLCT lifetime of 37 ps was recently observed on an Al2O3 nanofilm. As a proof of concept, it was further demonstrated that the significant improvement in the (3)MLCT lifetime indeed benefits efficient light harvesting with Fe(II) NHC complexes. For the first time, close-to-unity electron injection from the lowest-energy (3)MLCT state to a TiO2 nanofilm was achieved by a stable Fe(II) complex. This is in complete contrast to conventional Fe(II)L6-derived photosensitizers that could only make use of high-energy photons. These exciting results significantly broaden the understanding of the fundamental photophysics and photochemistry of d(6) Fe(II) complexes. They also open up new possibilities to develop solar energy-converting materials based on this abundant, inexpensive, and intrinsically nontoxic element.
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Affiliation(s)
- Yizhu Liu
- Centre
for Analysis and Synthesis, Lund University, Box 124, 22100 Lund, Sweden
- Department
of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Petter Persson
- Theoretical
Chemistry Division, Lund University, Box 124, 22100 Lund, Sweden
| | - Villy Sundström
- Department
of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Kenneth Wärnmark
- Centre
for Analysis and Synthesis, Lund University, Box 124, 22100 Lund, Sweden
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38
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Fredin LA, Wärnmark K, Sundström V, Persson P. Molecular and Interfacial Calculations of Iron(II) Light Harvesters. CHEMSUSCHEM 2016; 9:667-675. [PMID: 27010851 DOI: 10.1002/cssc.201600062] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Indexed: 06/05/2023]
Abstract
Iron-carbene complexes show considerable promise as earth-abundant light-harvesters, and adsorption onto nanostructured TiO2 is a crucial step for developing solar energy applications. Intrinsic electron injection capabilities of such promising Fe(II) N-heterocyclic complexes (Fe-NHC) to TiO2 are calculated here, and found to correlate well with recent experimental findings of highly efficient interfacial injection. First, we examine the special bonding characteristics of Fe-NHC light harvesters. The excited-state surfaces are examined using density functional theory (DFT) and time-dependent DFT (TD-DFT) to explore relaxed excited-state properties. Finally, by relaxing an Fe-NHC adsorbed on a TiO2 nanocluster, we show favorable injection properties in terms of interfacial energy level alignment and electronic coupling suitable for efficient electron injection of excited electrons from the Fe complex into the TiO2 conduction band on ∼100 fs time scales.
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Affiliation(s)
- Lisa A Fredin
- Division of Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-22100, Lund, Sweden
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100, Lund, Sweden
| | - Villy Sundström
- Division of Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-22100, Lund, Sweden
| | - Petter Persson
- Division of Theoretical Chemistry, Department of Chemistry, Lund University, Box 124, SE-22100, Lund, Sweden.
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39
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Hexakis (propargyl-1H-tetrazole) Iron(II) X2 [X = BF4, ClO4]—Spin Switchable Complexes with Functionalization Potential and the Myth of the Explosive SCO Compound. MAGNETOCHEMISTRY 2016. [DOI: 10.3390/magnetochemistry2010012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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40
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Zhang X, Pápai M, Møller KB, Zhang J, Canton SE. Characterizing the Solvated Structure of Photoexcited [Os(terpy)₂](2+) with X-ray Transient Absorption Spectroscopy and DFT Calculations. Molecules 2016; 21:235. [PMID: 26907233 PMCID: PMC6273819 DOI: 10.3390/molecules21020235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 02/12/2016] [Accepted: 02/15/2016] [Indexed: 11/16/2022] Open
Abstract
Characterizing the geometric and electronic structures of individual photoexcited dye molecules in solution is an important step towards understanding the interfacial properties of photo-active electrodes. The broad family of “red sensitizers” based on osmium(II) polypyridyl compounds often undergoes small photo-induced structural changes which are challenging to characterize. In this work, X-ray transient absorption spectroscopy with picosecond temporal resolution is employed to determine the geometric and electronic structures of the photoexcited triplet state of [Os(terpy)2]2+ (terpy: 2,2′:6′,2″-terpyridine) solvated in methanol. From the EXAFS analysis, the structural changes can be characterized by a slight overall expansion of the first coordination shell [OsN6]. DFT calculations supports the XTA results. They also provide additional information about the nature of the molecular orbitals that contribute to the optical spectrum (with TD-DFT) and the near-edge region of the X-ray spectra.
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Affiliation(s)
- Xiaoyi Zhang
- X-ray Sciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA.
| | - Mátyás Pápai
- Department of Chemistry, Technical University of Denmark, Kongens Lyngby DK-2800, Denmark.
- Wigner Research Centre for Physics, Hungarian Academy of Sciences, "Lendület" (Momentum) Femtosecond Spectroscopy Research Group, P.O. Box 49, Budapest H-1525, Hungary.
| | - Klaus B Møller
- Department of Chemistry, Technical University of Denmark, Kongens Lyngby DK-2800, Denmark.
| | - Jianxin Zhang
- School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
| | - Sophie E Canton
- Deutsches Elecktronen Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany.
- IFG Structural Dynamics of (Bio)Chemical Systems, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen D-37077, Germany.
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41
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Stępniewski A, Radoń M, Góra-Marek K, Broclawik E. Ammonia-modified Co(II) sites in zeolites: spin and electron density redistribution through the Co(II)-NO bond. Phys Chem Chem Phys 2016; 18:3716-29. [PMID: 26761131 DOI: 10.1039/c5cp07452e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electronic factors essential for the bonding of a non-innocent NO ligand to ammonia-modified Co(2+) sites in cobalt-exchanged zeolites are examined for small cluster models using DFT and advanced correlated wave function calculations. The analysis of charge transfer processes between the NO ligand and the cobalt center involves two protocols: valence-bond expansion of the multiconfiguration CASSCF wave function (in terms of fragment-localized active orbitals) and spin-resolved natural orbitals for chemical valence (SR-NOCV). Applicability of SR-NOCV analysis to transition metal complexes involving non-innocent fragments is critically assessed and the approach based on the CASSCF wave function turns out to be much more robust and systematic for all studied models. It is shown that the character and direction of electron density redistribution through the Co-N-O bond, quantified by relative share of the Co(II)-NO(0), Co(III)-NO(-), and Co(I)-NO(+) resonance structures in the total wave function, fully rationalize the activation of the N-O bond upon NH3 co-ligation (evidenced by calculated and measured red-shift of the NO stretching frequency and commonly ascribed to enhanced backdonation). The huge red-shift of νN-O is attributed to an effective electron transfer between the ammonia-modified Co(ii) centers and the NO antibonding π*-orbitals (related to the increased share of the Co(III)-NO(-) form). Unexpectedly, the effect is stronger for the singlet complex with three NH3 ligands than for that with five NH3 ligands bound to the cobalt center. Our results also indicate that high-efficiency electron transfers between the Co(ii) center and the NO ligand may be enabled for the selected spin state and disabled for the other spin state of the adduct. This illustrates how the cobalt center may serve to fine-tune the electronic communication between the NO ligand and its binding site.
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Affiliation(s)
- Adam Stępniewski
- Jerzy Haber Institute of Catalysis PAS, Niezapominajek 8, 30-239 Krakow, Poland.
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42
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Krewald V, Pantazis DA. Understanding and tuning the properties of redox-accumulating manganese helicates. Dalton Trans 2016; 45:18900-18908. [DOI: 10.1039/c6dt02800d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The multiple redox transitions of pentanuclear Mn clusters and the tuning of their redox potentials by ligand design are investigated computationally.
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Affiliation(s)
- Vera Krewald
- Max Planck Institute for Chemical Energy Conversion
- 45470 Mülheim an der Ruhr
- Germany
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43
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Saureu S, de Graaf C. TD-DFT study of the light-induced spin crossover of Fe(iii) complexes. Phys Chem Chem Phys 2016; 18:1233-44. [DOI: 10.1039/c5cp06620d] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Two light-induced spin-crossover Fe(iii) compounds have been studied with time-dependent density functional theory (TD-DFT) to investigate the deactivation mechanism and the role of the ligand-field states as intermediates in this process.
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Affiliation(s)
- Sergi Saureu
- Departament de Química Física i Inorgànica
- Universitat Rovira i Virgili
- 43007 Tarragona
- Spain
| | - Coen de Graaf
- Departament de Química Física i Inorgànica
- Universitat Rovira i Virgili
- 43007 Tarragona
- Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA)
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44
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Iuchi S, Koga N. Insight into the light-induced spin crossover of [Fe(bpy)3]2+ in aqueous solution from molecular dynamics simulation of d–d excited states. Phys Chem Chem Phys 2016; 18:4789-99. [DOI: 10.1039/c5cp06406f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lifetimes of triplet d–d states were evaluated through molecular dynamics simulations to gain insight into relaxation dynamics of aqueous [Fe(bpy)3]2+.
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Affiliation(s)
- Satoru Iuchi
- Graduate School of Information Science
- Nagoya University
- Nagoya 464-8601
- Japan
| | - Nobuaki Koga
- Graduate School of Information Science
- Nagoya University
- Nagoya 464-8601
- Japan
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45
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Nance J, Bowman DN, Mukherjee S, Kelley CT, Jakubikova E. Insights into the Spin-State Transitions in [Fe(tpy)2]2+: Importance of the Terpyridine Rocking Motion. Inorg Chem 2015; 54:11259-68. [DOI: 10.1021/acs.inorgchem.5b01747] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- James Nance
- Department of Mathematics and ‡Department of
Chemistry, North Carolina State University (NCSU), Raleigh, North Carolina 27695, United States
| | - David N. Bowman
- Department of Mathematics and ‡Department of
Chemistry, North Carolina State University (NCSU), Raleigh, North Carolina 27695, United States
| | - Sriparna Mukherjee
- Department of Mathematics and ‡Department of
Chemistry, North Carolina State University (NCSU), Raleigh, North Carolina 27695, United States
| | - C. T. Kelley
- Department of Mathematics and ‡Department of
Chemistry, North Carolina State University (NCSU), Raleigh, North Carolina 27695, United States
| | - Elena Jakubikova
- Department of Mathematics and ‡Department of
Chemistry, North Carolina State University (NCSU), Raleigh, North Carolina 27695, United States
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Joshi K, Krishnamurty S, Singh I, Selvaraj K. A DFT based assay for tailor-made terpyridine ligand–metal complexation properties. MOLECULAR SIMULATION 2015. [DOI: 10.1080/08927022.2015.1067368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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47
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Abstract
It is known that excitation by visible light of the singlet metal-to-ligand charge-transfer ((1)MLCT) states of Fe(II) complexes leads to population of the lowest-lying high-spin quintet state ((5)T) with unity quantum yield. Here we investigate this so-called spin crossover (SCO) transition in aqueous iron(II)tris(bipyridine). We use pump-probe transient absorption spectroscopy with a high time resolution of <60 fs in the ultraviolet probe range, in which the (5)T state absorbs, and of <40 fs in the visible probe range, in which both the hot MLCT state and the (5)T state absorb. Our results show that the (5)T state is impulsively populated in less than 50 fs, which is the time we measured for the depopulation of the MCLT manifold. We propose that non-totally-symmetric modes mediate the process, possibly high-frequency modes of the bipyridine (bpy) ligand. These results show that even though the SCO process in Fe(II) complexes represents a strongly spin-forbidden (ΔS = 2) two-electron transition, spin flipping occurs at near subvibrational times and is intertwined with the electron and structural dynamics of the system.
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Affiliation(s)
- Gerald Auböck
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, Faculté des Sciences de Base, ISIC, Lausanne CH-1015, Switzerland
| | - Majed Chergui
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, Faculté des Sciences de Base, ISIC, Lausanne CH-1015, Switzerland
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48
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Vlahović F, Perić M, Gruden-Pavlović M, Zlatar M. Assessment of TD-DFT and LF-DFT for study of d − d transitions in first row transition metal hexaaqua complexes. J Chem Phys 2015; 142:214111. [DOI: 10.1063/1.4922111] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Filip Vlahović
- Innovation center of the Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Republic of Serbia
| | - Marko Perić
- Department of Chemistry, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Republic of Serbia
| | - Maja Gruden-Pavlović
- Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Republic of Serbia
| | - Matija Zlatar
- Department of Chemistry, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Republic of Serbia
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49
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Jakubikova E, Bowman DN. Fe(II)-Polypyridines as Chromophores in Dye-Sensitized Solar Cells: A Computational Perspective. Acc Chem Res 2015; 48:1441-9. [PMID: 25919490 DOI: 10.1021/ar500428t] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Over the past two decades, dye-sensitized solar cells (DSSCs) have become a viable and relatively cheap alternative to conventional crystalline silicon-based systems. At the heart of a DSSC is a wide band gap semiconductor, typically a TiO2 nanoparticle network, sensitized with a visible light absorbing chromophore. Ru(II)-polypyridines are often utilized as chromophores thanks to their chemical stability, long-lived metal-to-ligand charge transfer (MLCT) excited states, tunable redox potentials, and near perfect quantum efficiency of interfacial electron transfer (IET) into TiO2. More recently, coordination compounds based on first row transition metals, such as Fe(II)-polypyridines, gained some attention as potential sensitizers in DSSCs due to their low cost and abundance. While such complexes can in principle sensitize TiO2, they do so very inefficiently since their photoactive MLCT states undergo intersystem crossing (ISC) into low-lying metal-centered states on a subpicosecond time scale. Competition between the ultrafast ISC events and IET upon initial excitation of Fe(II)-polypyridines is the main obstacle to their utilization in DSSCs. Suitability of Fe(II)-polypyridines to serve as sensitizers could therefore be improved by adjusting relative rates of the ISC and IET processes, with the goal of making the IET more competitive with ISC. Our research program in computational inorganic chemistry utilizes a variety of tools based on density functional theory (DFT), time-dependent density functional theory (TD-DFT) and quantum dynamics to investigate structure-property relationships in Fe(II)-polypyridines, specifically focusing on their function as chromophores. One of the difficult problems is the accurate determination of energy differences between electronic states with various spin multiplicities (i.e., (1)A, (1,3)MLCT, (3)T, (5)T) in the ISC cascade. We have shown that DFT is capable of predicting the trends in the energy ordering of these electronic states in a set of structurally related complexes with the help of appropriate benchmarks, based either on experimental data or higher-level ab initio calculations. Models based on TD-DFT and quantum dynamics approaches have proven very useful in understanding IET processes in Fe(II)-polypyridine-TiO2 assemblies. For example, they helped us to elucidate the origin of "band selective" sensitization in the [Fe(bpy-dca)2(CN)2]-TiO2 assembly (bpy-dca = 2,2'-bipyridine-4,4'-dicarboxylic acid), first observed by Ferrere and Gregg [ Ferrere , S. ; Gregg , B. A. J. Am. Chem. Soc. 1998 , 120 , 843 . ]. They also shed light on the relationship between the linker group that anchors Fe(II)-polypyridines onto the TiO2 surface and the speed of IET in Fe(II)-polypyridine-TiO2 assemblies. More interestingly, our results show that the IET efficiency is strongly correlated with the amount of electron density on the linker group and that one can obtain insights into the IET in dye-semiconductor assemblies based on ground state electronic structure calculations alone. This may be useful for quick screening of a large number of complexes for use as potential sensitizers in DSSCs, especially if followed up by TD-DFT and quantum dynamics simulations for selected target compounds to confirm efficient sensitization. While our focus over the past few years has been exclusively on Fe(II)-polypyridines, the computational strategies outlined in this Account are applicable to a wide variety of sensitizers.
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Affiliation(s)
- Elena Jakubikova
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - David N. Bowman
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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50
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Vankó G, Bordage A, Pápai M, Haldrup K, Glatzel P, March AM, Doumy G, Britz A, Galler A, Assefa T, Cabaret D, Juhin A, van Driel TB, Kjær K, Dohn A, Møller KB, Lemke HT, Gallo E, Rovezzi M, Németh Z, Rozsályi E, Rozgonyi T, Uhlig J, Sundström V, Nielsen MM, Young L, Southworth SH, Bressler C, Gawelda W. Detailed Characterization of a Nanosecond-Lived Excited State: X-ray and Theoretical Investigation of the Quintet State in Photoexcited [Fe(terpy) 2] 2. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2015; 119:5888-5902. [PMID: 25838847 PMCID: PMC4368081 DOI: 10.1021/acs.jpcc.5b00557] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/24/2015] [Indexed: 05/19/2023]
Abstract
Theoretical predictions show that depending on the populations of the Fe 3d xy , 3d xz , and 3d yz orbitals two possible quintet states can exist for the high-spin state of the photoswitchable model system [Fe(terpy)2]2+. The differences in the structure and molecular properties of these 5B2 and 5E quintets are very small and pose a substantial challenge for experiments to resolve them. Yet for a better understanding of the physics of this system, which can lead to the design of novel molecules with enhanced photoswitching performance, it is vital to determine which high-spin state is reached in the transitions that follow the light excitation. The quintet state can be prepared with a short laser pulse and can be studied with cutting-edge time-resolved X-ray techniques. Here we report on the application of an extended set of X-ray spectroscopy and scattering techniques applied to investigate the quintet state of [Fe(terpy)2]2+ 80 ps after light excitation. High-quality X-ray absorption, nonresonant emission, and resonant emission spectra as well as X-ray diffuse scattering data clearly reflect the formation of the high-spin state of the [Fe(terpy)2]2+ molecule; moreover, extended X-ray absorption fine structure spectroscopy resolves the Fe-ligand bond-length variations with unprecedented bond-length accuracy in time-resolved experiments. With ab initio calculations we determine why, in contrast to most related systems, one configurational mode is insufficient for the description of the low-spin (LS)-high-spin (HS) transition. We identify the electronic structure origin of the differences between the two possible quintet modes, and finally, we unambiguously identify the formed quintet state as 5E, in agreement with our theoretical expectations.
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Affiliation(s)
- György Vankó
- Wigner
Research Centre for Physics, Hungarian Academy
Sciences, P.O.B. 49., H-1525 Budapest, Hungary
- E-mail:
| | - Amélie Bordage
- Wigner
Research Centre for Physics, Hungarian Academy
Sciences, P.O.B. 49., H-1525 Budapest, Hungary
| | - Mátyás Pápai
- Wigner
Research Centre for Physics, Hungarian Academy
Sciences, P.O.B. 49., H-1525 Budapest, Hungary
| | - Kristoffer Haldrup
- Centre
for Molecular Movies, Technical University
of Denmark, Department of Physics, DK-2800 Kgs. Lyngby, Denmark
| | - Pieter Glatzel
- European
Synchrotron Radiation Facility (ESRF), CS40220, Grenoble 38043 Cedex 9, France
| | - Anne Marie March
- X-ray
Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United
States
| | - Gilles Doumy
- X-ray
Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United
States
| | - Alexander Britz
- European
XFEL, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany
- The
Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Andreas Galler
- European
XFEL, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany
| | - Tadesse Assefa
- European
XFEL, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany
| | - Delphine Cabaret
- Institut
de Minéralogie, de Physique des Matériaux, et de Cosmochimie
(IMPMC), Sorbonne Universités - UPMC
Univ. Paris 06, UMR CNRS 7590, Muséum National d’Histoire
Naturelle, UR IRD 206, 4 Place Jussieu, F-75005 Paris, France
| | - Amélie Juhin
- Institut
de Minéralogie, de Physique des Matériaux, et de Cosmochimie
(IMPMC), Sorbonne Universités - UPMC
Univ. Paris 06, UMR CNRS 7590, Muséum National d’Histoire
Naturelle, UR IRD 206, 4 Place Jussieu, F-75005 Paris, France
| | - Tim B. van Driel
- Centre
for Molecular Movies, Technical University
of Denmark, Department of Physics, DK-2800 Kgs. Lyngby, Denmark
| | - Kasper
S. Kjær
- Centre
for Molecular Movies, Technical University
of Denmark, Department of Physics, DK-2800 Kgs. Lyngby, Denmark
- Department
of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Asmus Dohn
- Centre
for Molecular Movies, Technical University
of Denmark, Department of Chemistry, DK-2800 Kgs. Lyngby, Denmark
| | - Klaus B. Møller
- Centre
for Molecular Movies, Technical University
of Denmark, Department of Chemistry, DK-2800 Kgs. Lyngby, Denmark
| | - Henrik T. Lemke
- SLAC
National Accelerator Laboratory, Linac Coherent
Light Source, Menlo Park, California 94025, United States
| | - Erik Gallo
- European
Synchrotron Radiation Facility (ESRF), CS40220, Grenoble 38043 Cedex 9, France
| | - Mauro Rovezzi
- European
Synchrotron Radiation Facility (ESRF), CS40220, Grenoble 38043 Cedex 9, France
| | - Zoltán Németh
- Wigner
Research Centre for Physics, Hungarian Academy
Sciences, P.O.B. 49., H-1525 Budapest, Hungary
| | - Emese Rozsályi
- Wigner
Research Centre for Physics, Hungarian Academy
Sciences, P.O.B. 49., H-1525 Budapest, Hungary
| | - Tamás Rozgonyi
- Research
Centre for Natural Sciences, Hungarian Academy
of Sciences, P.O. Box 286, H-1519 Budapest, Hungary
| | - Jens Uhlig
- Department
of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Villy Sundström
- Department
of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Martin M. Nielsen
- Centre
for Molecular Movies, Technical University
of Denmark, Department of Physics, DK-2800 Kgs. Lyngby, Denmark
| | - Linda Young
- X-ray
Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United
States
| | - Stephen H. Southworth
- X-ray
Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United
States
| | - Christian Bressler
- European
XFEL, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany
- The
Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Wojciech Gawelda
- European
XFEL, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany
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