1
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Nemykin VN, Sabin JR, Kail BW, Upadhyay A, Hendrich MP, Basu P. Influence of the ligand-field on EPR parameters of cis- and trans-isomers in Mo V systems relevant to molybdenum enzymes: Experimental and density functional theory study. J Inorg Biochem 2023; 245:112228. [PMID: 37149488 PMCID: PMC10330323 DOI: 10.1016/j.jinorgbio.2023.112228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 04/12/2023] [Accepted: 04/12/2023] [Indexed: 05/08/2023]
Abstract
The electron paramagnetic resonance (EPR) investigation of mononuclear cis- and trans-(L1O)MoOCl2 complexes [L1OH = bis(3,5-dimethylpyrazolyl)-3-tert-butyl-2-hydroxy-5-methylphenyl)methane] reveals a significant difference in their spin Hamiltonian parameters which reflect different equatorial and axial ligand fields created by the heteroscorpionate donor atoms. Density functional theory (DFT) was used to calculate the values of principal components and relative orientations of the g and A tensors, and the molecular framework in four pairs of isomeric mononuclear oxo‑molybdenum(V) complexes (cis- and trans-(L1O)MoOCl2, cis,cis- and cis,trans-(L-N2S2)MoOCl [L-N2S2H2 = N,N'-dimethyl-N,N'-bis(mercaptophenyl)ethylenediamine], cis,cis- and cis,trans-(L-N2S2)MoO(SCN), and cis- and trans-[(dt)2MoO(OMe)]2- [dtH2 = 2,3-dimercapto-2-butene]). Scalar relativistic DFT calculations were conducted using three different exchange-correlation functionals. It was found that the use of hybrid exchange-correlation functional with 25% of the Hartree-Fock exchange leads to the best quantitative agreement between theory and experiment. A simplified ligand-field approach was used to analyze the influence of the ligand fields in all cis- and trans-isomers on energies and contributions of molybdenum d-orbital manifold to g and A tensors and relative orientations. Specifically, contributions that originated from the spin-orbit coupling of the dxz, dyz, and dx2-y2 orbitals into the ground state have been discussed. The new findings are discussed in the context of the experimental data of mononuclear molybdoenzyme, DMSO reductase.
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Affiliation(s)
- Victor N Nemykin
- Department of Chemistry, University of Tennessee - Knoxville, Knoxville, TN 37996, USA; Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN 55812, USA.
| | - Jared R Sabin
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN 55812, USA
| | - Brian W Kail
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15216, USA
| | - Anup Upadhyay
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Michael P Hendrich
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15216, USA; Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA.
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2
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Schrage BR, Zhou W, Harrison LA, Nevonen DE, Thompson JR, Prosser KE, Walsby CJ, Ziegler CJ, Leznoff DB, Nemykin VN. Resolving a Half-Century-Long Controversy between (Magneto)optical and EPR Spectra of Single-Electron-Reduced [PcFe] −, [PcFeL] −, and [PcFeX] 2– Complexes: Story of a Double Flip. Inorg Chem 2022; 61:20177-20199. [DOI: 10.1021/acs.inorgchem.2c03456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Briana R. Schrage
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Wen Zhou
- Department of Chemistry, Simon Fraser University, Burnaby, British ColumbiaV5A 1S6, Canada
| | - Laurel A. Harrison
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Dustin E. Nevonen
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - John R. Thompson
- Department of Chemistry, Simon Fraser University, Burnaby, British ColumbiaV5A 1S6, Canada
| | - Kathleen E. Prosser
- Department of Chemistry, Simon Fraser University, Burnaby, British ColumbiaV5A 1S6, Canada
| | - Charles J. Walsby
- Department of Chemistry, Simon Fraser University, Burnaby, British ColumbiaV5A 1S6, Canada
| | | | - Daniel B. Leznoff
- Department of Chemistry, Simon Fraser University, Burnaby, British ColumbiaV5A 1S6, Canada
| | - Victor N. Nemykin
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
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3
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Nevonen DE, Ferch LS, Schrage BR, Nemykin VN. Charge-Transfer Spectroscopy of Bisaxially Coordinated Iron(II) Phthalocyanines through the Prism of the Lever's EL Parameters Scale, MCD Spectroscopy, and TDDFT Calculations. Inorg Chem 2022; 61:8250-8266. [PMID: 35549169 DOI: 10.1021/acs.inorgchem.2c00721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The position of the experimentally observed (in the UV-vis and magnetic circular dichroism (MCD) spectra) low-energy metal-to-ligand charge-transfer (MLCT) band in low-spin iron(II) phthalocyanine complexes of general formula PcFeL2, PcFeL'L″, and [PcFeX2]2- (L, L', or L″ are neutral and X- is an anionic axial ligand) was correlated with the Lever's electrochemical EL scale values for the axial ligands. The time-dependent density functional theory (TDDFT)-predicted UV-vis spectra are in very good agreement with the experimental data for all complexes. In the majority of compounds, TDDFT predicts that the first degenerate MLCT band that correlates with the MCD A-term observed between 360 and 480 nm is dominated by an eg (Fe, dπ) → b1u (Pc, π*) single-electron excitation (in traditional D4h point group notation) and agrees well with the previous assignment discussed by Stillman and co-workers[ Inorg. Chem. 1994, 33, 573-583]. The TDDFT calculations also suggest a small energy gap for b1u/b2u (Pc, π*) orbital splitting and closeness of the MLCT1 eg (Fe, dπ) → b1u (Pc, π*) and MLCT2 eg (Fe, dπ) → b2u (Pc, π*) transitions. In the case of the PcFeL2 complexes with phosphines as the axial ligands, additional degenerate charge-transfer transitions were observed between 450 and 500 nm. These transitions are dominated by a2u (Pc + L, π) → eg (Pc, π*) single-electron excitations and are unique for the PcFe(PR3)2 complexes. The energy of the phthalocyanine-based a2u orbital has large axial ligand dependency and is the reason for a large energy deviation for B1 a2u (Pc + L, π) → eg (Pc, π*) transition. The energies of the axial ligand-to-iron, axial ligand-to-phthalocyanine, iron-to-axial ligand, and phthalocyanine-to-axial ligand charge-transfer transitions were discussed on the basis of TDDFT calculations.
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Affiliation(s)
- Dustin E Nevonen
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Laura S Ferch
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Briana R Schrage
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Victor N Nemykin
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.,Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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4
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Nemykin VN, Nevonen DE, Osterloh WR, Ferch LS, Harrison LA, Marx BS, Kadish KM. Application of Lever's EL Parameter Scale toward Fe(II)/Fe(III) versus Pc(2-)/Pc(1-) Oxidation Process Crossover Point in Axially Coordinated Iron(II) Phthalocyanine Complexes. Inorg Chem 2021; 60:16626-16644. [PMID: 34644056 DOI: 10.1021/acs.inorgchem.1c02520] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electronic structures and, particularly, the nature of the HOMO in a series of PcFeL2, PcFeL'L″, and [PcFeX2]2- complexes (Pc = phthalocyaninato(2-) ligand; L = NH3, n-BuNH2, imidazole (Im), pyridine (Py), PMe3, PBu3, t-BuNC, P(OBu)3, and DMSO; L' = CO; L″ = NH3 or n-BuNH2; X = NCO-, NCS-, CN-, imidazolate (Im-), or 1,2,4-triazolate(Tz-)) were probed by electrochemical, spectroelectrochemical, and chemical oxidation as well as theoretical (density functional theory, DFT) studies. In general, energies of the metal-centered occupied orbitals in various six-coordinate iron phthalocyanine complexes correlate well with Lever Electrochemical Parameter EL and intercross the phthalocyanine-centered a1u orbital in several compounds with moderate-to-strong π-accepting axial ligands. In these cases, an oxidation of the phthalocyanine macrocycle (Pc(2-)/Pc(1-)) rather than the central metal ion (Fe(II)/Fe(III)) was theoretically predicted and experimentally confirmed.
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Affiliation(s)
- Victor N Nemykin
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States.,Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Dustin E Nevonen
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - W Ryan Osterloh
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
| | - Laura S Ferch
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Laurel A Harrison
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Benjamin S Marx
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Karl M Kadish
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
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5
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Vecchi A, Sabin JR, Sabuzi F, Conte V, Cicero DO, Floris B, Galloni P, Nemykin VN. Similar, Yet Different: Long-Range Metal-Metal Coupling and Electron-Transfer Processes in Metal-Free 5,10,15,20-Tetra(ruthenocenyl)porphyrin. Inorg Chem 2021; 60:8227-8241. [PMID: 34033715 DOI: 10.1021/acs.inorgchem.1c00908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The electronic structure, redox properties, and long-range metal-metal coupling in metal-free 5,10,15,20-tetra(ruthenocenyl)porphyrin (H2TRcP) were probed by spectroscopic (NMR, UV-vis, magnetic circular dichroism (MCD), and atmospheric pressure chemical ionization (APCI)), electrochemical (cyclic voltammetry, CV, and differential pulse voltammetry, DPV), spectroelectrochemical, and chemical oxidation methods, as well as theoretical (density functional theory, DFT, and time-dependent DFT, TDDFT) approaches. It was demonstrated that the spectroscopic properties of H2TRcP are significantly different from those in H2TFcP (metal-free 5,10,15,20-tetra(ferrocenyl)porphyrin). Ruthenocenyl fragments in H2TRcP have higher oxidation potentials than the ferrocene groups in the H2TFcP complex. Similar to H2TFcP, we were able to access and spectroscopically characterize the one- and two-electron oxidized mixed-valence states in the H2TRcP system. DFT predicts that the porphyrin π-system stabilizes the [H2TRcP]+ mixed-valence cation and prevents its dimerization, which is characteristic for ruthenocenyl systems. However, formation of the mixed-valence [H2TRcP]2+ is significantly less reproducible than the formation of [H2TRcP]+. DFT and TDDFT calculations suggest the ruthenocenyl fragment dominance in the highest occupied molecular orbital (HOMO) energy region and the presence of the low-energy MLCT (Rc → porphyrin (π*)) transitions in the visible region with energies higher than the predominantly porphyrin-centered Q-bands.
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Affiliation(s)
- Andrea Vecchi
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, Rome 0133, Italy.,Department of Chemistry & Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, United States
| | - Jared R Sabin
- Department of Chemistry & Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, United States
| | - Federica Sabuzi
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, Rome 0133, Italy
| | - Valeria Conte
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, Rome 0133, Italy
| | - Daniel Oscar Cicero
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, Rome 0133, Italy
| | - Barbara Floris
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, Rome 0133, Italy
| | - Pierluca Galloni
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, Rome 0133, Italy
| | - Victor N Nemykin
- Department of Chemistry & Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, United States.,Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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6
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Zatsikha YV, Blesener TS, King AJ, Healy AT, Goff PC, Didukh NO, Blank DA, Kovtun YP, Nemykin VN. Fully Conjugated Pyrene-BODIPY and Pyrene-BODIPY-Ferrocene Dyads and Triads: Synthesis, Characterization, and Selective Noncovalent Interactions with Nanocarbon Materials. J Phys Chem B 2021; 125:360-371. [PMID: 33370123 DOI: 10.1021/acs.jpcb.0c10074] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several pyrene-boron-dipyrromethene (BODIPY) and pyrene-BODIPY-ferrocene derivatives with a fully conjugated pyrene fragment appended to the α-position(s) of the BODIPY core have been prepared by Knoevenagel condensation reaction and characterized by one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR), UV-vis, fluorescence spectroscopy, high-resolution mass spectrometry as well as X-ray crystallography. The redox properties of new donor-acceptor BODIPY dyads and triads were studied by electrochemical (cyclic voltammetry (CV) and differential pulse voltammetry (DPV)) and spectroelectrochemical approaches. Formation of weakly bonded noncovalent complexes between the new pyrene-BODIPYs and nanocarbon materials (C60, C70, single-walled carbon nanotube (SWCNT), and graphene) was studied by UV-vis, steady-state fluorescent, and time-resolved transient absorption spectroscopy. UV-vis and fluorescent spectroscopy are indicative of the much stronger and selective interaction between new dyes and (6,5)-SWCNT as well as graphene compared to that of C60 and C70 fullerenes. In agreement with these data, transient absorption spectroscopy provided no evidence for any significant change in excited-state lifetime or photoinduced charge transfer between pyrene-BODIPYs and C60 or C70 fullerenes when the pyrene-BODIPY chromophores were excited into the lowest-energy singlet excited state. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations suggest that the pyrene fragments are fully conjugated into the π-system of BODIPY core, which correlates well with the experimental data.
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Affiliation(s)
- Yuriy V Zatsikha
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Tanner S Blesener
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Alex J King
- Department of Chemistry & Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, United States
| | - Andrew T Healy
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Philip C Goff
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Natalia O Didukh
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.,Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 02660 Kyiv, Ukraine
| | - David A Blank
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Yuriy P Kovtun
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 02660 Kyiv, Ukraine
| | - Victor N Nemykin
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.,Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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7
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Tsaturyan AA, Budnyk AP, Ramalingan C. DFT Study of the CNS Ligand Effect on the Geometry, Spin-State, and Absorption Spectrum in Ruthenium, Iron, and Cobalt Quaterpyridine Complexes. ACS OMEGA 2019; 4:10991-11003. [PMID: 31460197 PMCID: PMC6647971 DOI: 10.1021/acsomega.9b00921] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/12/2019] [Indexed: 06/10/2023]
Abstract
Geometry parameters, total energy of the system in different spin states, harmonic vibrational frequencies, and absorption spectra were computed for a range of mononuclear quaterpyridine Ru(II), Fe(III/II), and Co(III/II) complexes with two axial ambidentate CNS ligands by using density functional theory (DFT) and time-dependent DFT calculations. Both structural and electronic properties were found to be correlating with the type of the binding atom in the CNS ligand (isomerization differs by 4-13 kcal·mol-1). The N-bonding of CNS ligands is energetically favored. It was also found that the low spin (LS) state is the ground state for both Ru(II) and Co(III) complexes regardless of the CNS arrangement. The other complexes are the high-spin (HS) ground-state ones with the only exception of the S-bonded CNS isomer of the Fe(III) complex. The dependencies of energy differences between the HS and LS states versus C demonstrated stabilization of the HS state with an increasing amount of the exact exchange admixture (C) for iron and cobalt complexes. An opposite behavior was observed for ruthenium complexes. The best match in harmonic vibrational frequencies between the experimental and calculated values has been reached at C = 0.15 for all the complexes. The absorption profile of the Fe(II) complex with the alternatively bonded CNS ligands strongly depends on the angle between them. The light-harvesting efficiency of the Fe(II) complexes is very similar (∼0.4) and sufficiently close to that of the Ru(II) complexes. The iron-based coordination compounds are considered as a prospective dye for dye-sensitized solar cells. The results of calculations were completed with experimental reference data, thus providing a systematic compendium for practical use.
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Affiliation(s)
- Arshak A. Tsaturyan
- Institute
of Physical and Organic Chemistry, Southern
Federal University, Stachki
Av. 194/2, 344090 Rostov-on-Don, Russian Federation
| | - Andriy P. Budnyk
- Southern
Scientific Center, Russian Academy of Sciences, 41 Chehova str, 344006 Rostov-on-Don, Russian
Federation
| | - Chennan Ramalingan
- Department
of Chemistry, School of Advanced Sciences, Kalasalingam Academy of Research and Education (Deemed to be University), Krishnankoil 626 126 Tamil Nadu, India
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8
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Chang AS, Pintauer T, Basu P, Eckenhoff WT. Structural and Electronic Investigation of Tetrachalcogenidomolybdate Dianions. ChemistrySelect 2018. [DOI: 10.1002/slct.201800506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Alison S. Chang
- Department of Chemistry Rhodes College 2000 N. Parkway Memphis TN 38112
| | - Tomislav Pintauer
- Department of Chemistry and Biochemistry Duquesne University 600 Forbes Ave., 308 Mellon Hall Pittsburgh PA 15282
| | - Partha Basu
- Department of Chemistry and Chemical Biology Indiana University-Purdue University Indianapolis 420 N. Blackford St. Indianapolis IN 46202
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9
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Maia LB, Moura I, Moura JJ. EPR Spectroscopy on Mononuclear Molybdenum-Containing Enzymes. FUTURE DIRECTIONS IN METALLOPROTEIN AND METALLOENZYME RESEARCH 2017. [DOI: 10.1007/978-3-319-59100-1_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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10
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Attia AAA, Cioloboc D, Lupan A, Silaghi-Dumitrescu R. Multiconfigurational and DFT analyses of the electromeric formulation and UV-vis absorption spectra of the superoxide adduct of ferrous superoxide reductase. J Inorg Biochem 2016; 165:49-53. [PMID: 27768962 DOI: 10.1016/j.jinorgbio.2016.09.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Revised: 09/14/2016] [Accepted: 09/29/2016] [Indexed: 11/29/2022]
Abstract
The putative initial adduct of ferrous superoxide reductase (SOR) with superoxide has been alternatively formulated as ferric-peroxo or ferrous-superoxo. The ~600-nm UV-vis absorption band proposed to be assigned to this adduct (either as sole intermediate in the SOR catalytic cycle, or as one of the two intermediates) has recently been interpreted as due to a ligand-to-metal charge transfer, involving thiolate and superoxide in a ferrous complex, contrary to an alternative assignment as a predominantly cysteine thiolate-to-ferric charge transfer in a ferric-peroxo electromer. In an attempt to clarify the electromeric formulation of this adduct, we report a computational study using a multiconfigurational complete active space self-consistent field (MC-CASSCF) wave function approach as well as modelling the UV-vis absorption spectra with time-dependent density functional theory (TD-DFT). The MC-CASSCF calculations disclose a weak interaction between iron and the dioxygenic ligand and a dominant configuration with an essentially ferrous-superoxo character. The computed UV-vis absorption spectra reveal a marked dependence on the choice of density functional - both in terms of location of bands and in terms of orbital contributors. For the main band in the visible region, besides the recently reported thiolate-to-superoxide charge transfer, a more salient, and less functional-dependent, feature is a thiolate-to-ferric iron charge transfer, consistent with a ferric-peroxo electromer. By contrast, the computed UV-vis spectra of a ferric-hydroperoxo SOR model match distinctly better (and with no qualitative dependence on the DFT methodology) the 600-nm band as due to a mainly thiolate-to-ferric character - supporting the assignment of the SOR "600-nm intermediate" as a S=5/2 ferric-hydroperoxo species.
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Affiliation(s)
- Amr A A Attia
- Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Daniela Cioloboc
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, United States
| | - Alexandru Lupan
- Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Radu Silaghi-Dumitrescu
- Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania.
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11
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Young CG. Chemical systems modeling the d1 Mo(V) states of molybdenum enzymes. J Inorg Biochem 2016; 162:238-252. [PMID: 27432259 DOI: 10.1016/j.jinorgbio.2016.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/14/2016] [Accepted: 06/03/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Charles G Young
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
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12
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Sparacino-Watkins C, Stolz JF, Basu P. Nitrate and periplasmic nitrate reductases. Chem Soc Rev 2014; 43:676-706. [PMID: 24141308 DOI: 10.1039/c3cs60249d] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The nitrate anion is a simple, abundant and relatively stable species, yet plays a significant role in global cycling of nitrogen, global climate change, and human health. Although it has been known for quite some time that nitrate is an important species environmentally, recent studies have identified potential medical applications. In this respect the nitrate anion remains an enigmatic species that promises to offer exciting science in years to come. Many bacteria readily reduce nitrate to nitrite via nitrate reductases. Classified into three distinct types--periplasmic nitrate reductase (Nap), respiratory nitrate reductase (Nar) and assimilatory nitrate reductase (Nas), they are defined by their cellular location, operon organization and active site structure. Of these, Nap proteins are the focus of this review. Despite similarities in the catalytic and spectroscopic properties Nap from different Proteobacteria are phylogenetically distinct. This review has two major sections: in the first section, nitrate in the nitrogen cycle and human health, taxonomy of nitrate reductases, assimilatory and dissimilatory nitrate reduction, cellular locations of nitrate reductases, structural and redox chemistry are discussed. The second section focuses on the features of periplasmic nitrate reductase where the catalytic subunit of the Nap and its kinetic properties, auxiliary Nap proteins, operon structure and phylogenetic relationships are discussed.
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13
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van Stipdonk MJ, Basu P, Dille SA, Gibson JK, Berden G, Oomens J. Infrared multiple photon dissociation spectroscopy of a gas-phase oxo-molybdenum complex with 1,2-dithiolene ligands. J Phys Chem A 2014; 118:5407-18. [PMID: 24988369 PMCID: PMC4338922 DOI: 10.1021/jp503222v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
![]()
Electrospray
ionization (ESI) in the negative ion mode was used
to create anionic, gas-phase oxo-molybdenum complexes with dithiolene
ligands. By varying ESI and ion transfer conditions, both doubly and
singly charged forms of the complex, with identical formulas, could
be observed. Collision-induced dissociation (CID) of the dianion generated
exclusively the monoanion, while fragmentation of the monoanion involved
decomposition of the dithiolene ligands. The intrinsic structure of
the monoanion and the dianion were determined by using wavelength-selective
infrared multiple-photon dissociation (IRMPD) spectroscopy and density
functional theory calculations. The IRMPD spectrum for the dianion
exhibits absorptions that can be assigned to (ligand) C=C,
C–S, C—C≡N, and Mo=O stretches. Comparison
of the IRMPD spectrum to spectra predicted for various possible conformations
allows assignment of a pseudo square pyramidal structure with C2v symmetry, equatorial coordination
of MoO2+ by the S atoms of the dithiolene ligands, and
a singlet spin state. A single absorption was observed for the oxidized
complex. When the same scaling factor employed for the dianion is
used for the oxidized version, theoretical spectra suggest that the
absorption is the Mo=O stretch for a distorted square pyramidal
structure and doublet spin state. A predicted change in conformation
upon oxidation of the dianion is consistent with a proposed bonding
scheme for the bent-metallocene dithiolene compounds [Lauher, J. W.; Hoffmann, R. J. Am.
Chem. Soc.1976, 98, 1729−1742], where a large
folding of the dithiolene moiety along the S···S vector
is dependent on the occupancy of the in-plane metal d-orbital.
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Affiliation(s)
- Michael J van Stipdonk
- Department of Chemistry and Biochemistry, Duquesne University , 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, United States
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14
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Affiliation(s)
- Russ Hille
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - James Hall
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
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15
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Sabin JR, Varzatskii OA, Voloshin YZ, Starikova ZA, Novikov VV, Nemykin VN. Insight into the electronic structure, optical properties, and redox behavior of the hybrid phthalocyaninoclathrochelates from experimental and density functional theory approaches. Inorg Chem 2012; 51:8362-72. [PMID: 22800298 DOI: 10.1021/ic3008798] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An insight into the electronic structure of several hafnium(IV), zirconium(IV), and lutetium(III) phthalocyaninoclathrochelates has been discussed on the basis of experimental UV-vis, MCD, electro- and spectroelectrochemical data as well as density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. On the basis of UV-vis and MCD spectroscopy as well as theoretical predictions, it was concluded that the electronic structure of the phthalocyninoclathrochelates can be described in the first approximation as a superposition of the weakly interacting phthalocyanine and clathrochelate substituents. Spectroelectrochemical data and DFT calculations clearly confirm that the highest occupied molecular orbital (HOMO) in all tested complexes is localized on the phthalocyanine ligand. X-ray crystallography on zirconium(IV) and earlier reported hafnium(IV) phthalocyaninoclathrochelate complexes revealed a slightly distorted phthalocyanine conformation with seven-coordinated metal center positioned ∼1 Å above macrocyclic cavity. The geometry of the encapsulated iron(II) ion in the clathrochelate fragment was found to be between trigonal-prismatic and trigonal-antiprismatic.
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Affiliation(s)
- Jared R Sabin
- Department of Chemistry & Biochemistry, 1039 University Drive, University of Minnesota Duluth, Duluth, Minnesota 55812, United States
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16
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Li XJ, Sun SL, Ma NN, Sun XX, Yang GC, Qiu YQ. Theoretical investigations on electronic spectra and the redox-switchable second-order nonlinear optical responses of rhodium(I)-9,10-phenanthrenediimine complexes. J Mol Graph Model 2011; 33:19-25. [PMID: 22138015 DOI: 10.1016/j.jmgm.2011.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 11/04/2011] [Accepted: 11/07/2011] [Indexed: 10/15/2022]
Abstract
The redox-switchable second-order nonlinear optical (NLO) properties of a series of Rh(I) complexes have been studied based on density functional theory (DFT) calculations. The analysis of the electronic structure shows that the Rh(I) ion acts as the oxidation center in a one-electron-oxidized process, while both the Rh(I) ion and the 9,10-phenanthrenediimine (phdi) ligand act as reduction centers in a one-electron-reduced process. Different redox centers lead to different charge-transfer (CT) features, which alter the static first hyperpolarizabilities of the neutral complexes. Our DFT calculations indicated that these complexes show large second-order NLO responses and that the redox process can significantly enhance these NLO responses. For complexes 2 and 3, the β(tot) values of the one-electron-reduced species 2(-) and the one-electron-oxidized species 3(+) are ~10.0 and ~8.5 times larger, respectively, than those of the corresponding neutral complexes. Therefore, complexes 2 and 3 are promising candidates for redox-switchable NLO molecular materials. The large NLO responses of the oxidized species are mainly related to ligand-to-ligand charge-transfer (LLCT) transitions when combined with intraligand charge-transfer (ILCT) transitions, while the results for the reduced species are strongly associated with metal-to-ligand charge-transfer (MLCT) transitions.
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Affiliation(s)
- Xiao-Juan Li
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, People's Republic of China
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17
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Zárate X, Schott E, Mac-Leod Carey D, Bustos C, Arratia-Pérez R. DFT study on the electronic structure, energetics and spectral properties of several bis(organohydrazido(2-)) molybdenum complexes containing substituted phosphines and chloro atoms as ancillary ligands. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.theochem.2010.07.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Zhao HB, Qiu YQ, Liu CG, Sun SL, Liu Y, Wang RS. Redox-switchable second-order nonlinear optical responses of TEMPO-dithiolate ligand and (tempodt)M complexes (M = Pt, Pd). J Organomet Chem 2010. [DOI: 10.1016/j.jorganchem.2010.06.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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19
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A density functional theory study of multioxomolybdenum(VI) compounds [Mo2O6(imi)6] (imi=imidazole) and Mo2O6: Structure, bonding, and properties. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.theochem.2010.04.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Hernandez-Marin E, Seth M, Ziegler T. Density Functional Theory Study of the Magnetic Circular Dichroism Spectra of Molybdenyl Complexes. Inorg Chem 2010; 49:6066-76. [DOI: 10.1021/ic100624q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Michael Seth
- Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Tom Ziegler
- Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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21
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Investigation of the UV–Vis absorption of bis(N-methylthiosemicarbazonato) zinc Zn[ATSM]. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2009.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Hadt RG, Nemykin VN, Olsen JG, Basu P. Comparative calculation of EPR spectral parameters in [Mo(V)OX4]-, [Mo(V)OX5]2-, and [Mo(V)OX4(H2O)]- complexes. Phys Chem Chem Phys 2009; 11:10377-84. [PMID: 19890522 PMCID: PMC2879133 DOI: 10.1039/b905554a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The EPR spectral parameters, i.e. g-tensors and molybdenum hyperfine couplings, for several d(1) systems of the general formula [Mo(V)EX(4)](n-), [Mo(V)OX(5)](2-), and [Mo(V)OX(4)(H(2)O)](-) (E = O, N; X = F, Cl, Br; n = 1 or 2) were calculated using Density Functional Theory. The influence of basis sets, their contraction scheme, the type of exchange-correlation functional, the amount of Hartree-Fock exchange, molecular geometry, and relativistic effects on the calculated EPR spectra parameters have been discussed. The g-tensors and molybdenum hyperfine coupling parameters were calculated using a relativistic Hamiltonian coupled with several LDA, GGA, and 'hybrid' exchange-correlation functionals and uncontracted full-electron DGauss DZVP basis sets. The calculated EPR parameters are found to be sensitive to the Mo=E distance and E=Mo-Cl angle, and thus the choice of starting molecular geometry should be considered as an important factor in predicting the g-tensors and hyperfine coupling constants in oxo-molybdenum compounds. In the present case, the GGA exchange-correlation functionals provide a better agreement between the theory and the experiment.
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Affiliation(s)
- Ryan G. Hadt
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN 55812, USA.
| | - Victor N. Nemykin
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN 55812, USA.
| | - Joseph G. Olsen
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN 55812, USA.
| | - Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, USA.
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23
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Rosa A, Ricciardi G. A time-dependent density functional theory (TDDFT) interpretation of the optical spectra of zinc phthalocyanine π-cation and π-anion radicals. CAN J CHEM 2009. [DOI: 10.1139/v09-066] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The UV–visible and near-IR spectra of the zinc phthalocyanine π-cation and π-anion radicals, [ZnPc(–1)]•+ and [ZnPc(–3)]•–, are investigated by time-dependent density functional theory (TDDFT) calculations using the pure, asymptotically correct, statistical average of (model) orbital potentials (SAOP) functional. The nature and intensity of the main spectral features are highlighted and interpreted on the basis of the ground-state electronic structure of the complexes. Similarities and differences with previous TDDFT/B3LYP results are discussed. TDDFT/SAOP results for the π-anion radical prove to be in excellent agreement with the solution spectra and generally in line with deconvolution analyses of solution absorption and magnetic circular dichroism (MCD) spectra. On the basis of these results a novel interpretation of the Q-band system is proposed. For the π-cation radical TDDFT/SAOP calculations provide a satisfactory description of the UV region of the spectrum. However, they do not reproduce accurately the energy and intensity of the Q band observed at 825 nm. The description of the Q-band region appears to be complicated by the presence of spurious non-Gouterman transitions. Furthermore, the calculations, either in the gas phase or in solution, do not account for the broad absorption near 500 nm that has been suggested to arise from a nondegenerate, z-polarized 2A2g excited state. Theory and experiment can be reconciled if the presence of an axial ligand such as CN– is explicitly considered in the calculations. TDDFT/SAOP results for the axially ligated [ZnPc(–1)(CN)]• species indicate that the 500 nm feature is related to the axial ligation induced symmetry lowering of the π-cation radical and this band is assigned to a z-polarized transition associated with the hole in the 2a1u.
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Affiliation(s)
- Angela Rosa
- Dipartimento di Chimica, Università della Basilicata, Via N. Sauro 85, 85100 Potenza, Italy
| | - Giampaolo Ricciardi
- Dipartimento di Chimica, Università della Basilicata, Via N. Sauro 85, 85100 Potenza, Italy
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24
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Hadt RG, Nemykin VN. Exploring the ground and excited state potential energy landscapes of the mixed-valence biferrocenium complex. Inorg Chem 2009; 48:3982-92. [PMID: 19344155 DOI: 10.1021/ic801801m] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Density functional theory (DFT) and time-dependent DFT (TDDFT) have been used to explore the potential energy landscapes in the class II (in Robin and Day classification) mixed-valence biferrocenium mono-cation (BF(+)) in an effort to evaluate factors affecting optical and thermal intramolecular electron transfer rates. Both energy- and spectroscopy-based benchmarks were used to explore the adiabatic potential energy surfaces (PESs) of the mixed-valence BF(+) cation along with the optimization of appropriate ground-, excited-, and transition-state geometries. The calculation of Mossbauer isomer shifts and quadrupole splittings, UV-vis excitation energies, and the electronic coupling matrix element, H(ab), corroborate the PES analyses. The adiabatic electron transfer pathway is also analyzed with respect to several possible vibronic coordinates. The degree of the electronic coupling between iron sites, the value of H(ab), and the nature of the electron transfer pathway correlate with the amount of Hartree-Fock exchange involved in the DFT calculation with hybrid (approximately 20% of Hartree-Fock exchange) methods providing the best agreement between theory and experiment. DFT (B3LYP) predicted values of H(ab) (839, 1085, and 1265 cm(-1)) depend on the computational method and are in good agreement with experimental data.
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Affiliation(s)
- Ryan G Hadt
- Department of Chemistry & Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, USA
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25
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Basu P, Nemykin VN, Sengar RS. Substituent Effect on Oxygen Atom Transfer Reactivity from Oxomolybdenum Centers: Synthesis, Structure, Electrochemistry, and Mechanism. Inorg Chem 2009; 48:6303-13. [DOI: 10.1021/ic900579s] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282
| | - Victor N. Nemykin
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282
| | - Raghvendra S. Sengar
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282
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26
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Sun SL, Qin CS, Qiu YQ, Yang GC, Su ZM. Theoretical investigation of structures, electronic spectra and nonlinear optical properties of gold-pentacene (Au2C22H14) complexes. J Organomet Chem 2009. [DOI: 10.1016/j.jorganchem.2008.11.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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27
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Synthesis, X-ray structure, spectroscopic properties, and theoretical investigations of dinuclear imidazole molybdenum(VI) complex with long MoO bands. INORG CHEM COMMUN 2009. [DOI: 10.1016/j.inoche.2009.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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28
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Fan J, Seth M, Autschbach J, Ziegler T. Circular Dichroism of Trigonal Dihedral Chromium(III) Complexes: A Theoretical Study based on Open-Shell Time-Dependent Density Functional Theory. Inorg Chem 2008; 47:11656-68. [DOI: 10.1021/ic801229c] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jing Fan
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada, T2N 1N4, and Department of Chemistry, University at Buffalo, State University of New York, 312 Natural Science Complexes, Buffalo, New York 14260-30000
| | - Michael Seth
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada, T2N 1N4, and Department of Chemistry, University at Buffalo, State University of New York, 312 Natural Science Complexes, Buffalo, New York 14260-30000
| | - Jochen Autschbach
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada, T2N 1N4, and Department of Chemistry, University at Buffalo, State University of New York, 312 Natural Science Complexes, Buffalo, New York 14260-30000
| | - Tom Ziegler
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada, T2N 1N4, and Department of Chemistry, University at Buffalo, State University of New York, 312 Natural Science Complexes, Buffalo, New York 14260-30000
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29
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Guan W, Yang G, Liu C, Song P, Fang L, Yan L, Su Z. Reversible Redox-Switchable Second-Order Optical Nonlinearity in Polyoxometalate: A Quantum Chemical Study of [PW11O39(ReN)]n− (n = 3−7). Inorg Chem 2008; 47:5245-52. [DOI: 10.1021/ic8001527] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Wei Guan
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China
| | - Guochun Yang
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China
| | - Chunguang Liu
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China
| | - Ping Song
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China
| | - Liang Fang
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China
| | - Likai Yan
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China
| | - Zhongmin Su
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China
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30
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Nemykin VN, Hadt RG, Belosludov RV, Mizuseki H, Kawazoe Y. Influence of Molecular Geometry, Exchange-Correlation Functional, and Solvent Effects in the Modeling of Vertical Excitation Energies in Phthalocyanines Using Time-Dependent Density Functional Theory (TDDFT) and Polarized Continuum Model TDDFT Methods: Can Modern Computational Chemistry Methods Explain Experimental Controversies? J Phys Chem A 2007; 111:12901-13. [DOI: 10.1021/jp0759731] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Victor N. Nemykin
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, and Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Ryan G. Hadt
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, and Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Rodion V. Belosludov
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, and Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Hiroshi Mizuseki
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, and Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Yoshiyuki Kawazoe
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, and Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
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31
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Nemykin VN, Makarova EA, Grosland JO, Hadt RG, Koposov AY. Preparation, Characterization, Molecular and Electronic Structures, TDDFT, and TDDFT/PCM Study of the Solvatochromism in Cyanovinylferrocenes. Inorg Chem 2007; 46:9591-601. [DOI: 10.1021/ic700558v] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Victor N. Nemykin
- Department of Chemistry and Biochemistry, 1039 University Drive, University of Minnesota, Duluth, Minnesota 55812, and Organic Intermediates and Dyes Institute, 1/4 B. Sadovaya Street, Moscow, 103787, Russia
| | - Elena A. Makarova
- Department of Chemistry and Biochemistry, 1039 University Drive, University of Minnesota, Duluth, Minnesota 55812, and Organic Intermediates and Dyes Institute, 1/4 B. Sadovaya Street, Moscow, 103787, Russia
| | - Jeffrey O. Grosland
- Department of Chemistry and Biochemistry, 1039 University Drive, University of Minnesota, Duluth, Minnesota 55812, and Organic Intermediates and Dyes Institute, 1/4 B. Sadovaya Street, Moscow, 103787, Russia
| | - Ryan G. Hadt
- Department of Chemistry and Biochemistry, 1039 University Drive, University of Minnesota, Duluth, Minnesota 55812, and Organic Intermediates and Dyes Institute, 1/4 B. Sadovaya Street, Moscow, 103787, Russia
| | - Alexey Y. Koposov
- Department of Chemistry and Biochemistry, 1039 University Drive, University of Minnesota, Duluth, Minnesota 55812, and Organic Intermediates and Dyes Institute, 1/4 B. Sadovaya Street, Moscow, 103787, Russia
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32
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Kim SR, He J, Yanase E, Jang YP, Berova N, Nakanishi K, Sparrow JR. Characterization of dihydro-A2PE: an intermediate in the A2E biosynthetic pathway. Biochemistry 2007; 46:10122-9. [PMID: 17685561 PMCID: PMC2557066 DOI: 10.1021/bi7009635] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bisretinoid lipofuscin pigments that accumulate in retinal pigment epithelial cells are implicated in the etiology of several forms of macular degeneration, including juvenile onset Stargardt disease, Best vitelliform macular degeneration, and age-related macular degeneration. One of these compounds, A2E, is generated by phosphate hydrolysis of a phosphatidyl-pyridinium bisretinoid (A2PE) that forms within photoreceptor outer segments. Here, we demonstrate that the formation of the aromatic pyridinium ring of A2PE follows from the oxidation of a dihydropyridinium intermediate. Time-dependent density functional theory calculation, based on the structure of dihydro-A2E, produced a simulated UV-visible absorbance spectrum characterized by maxima of 494 and 344 nm. Subsequently, a compound exhibiting similar UV-visible absorbance maxima (lambdamax 490 and 330 nm) was identified in the A2E biomimetic reaction mixture. By liquid chromatography-mass spectrometry (LC-MS) this bischromophore had the expected mass of the dihydro-pyridinium bisretinoid. The compound also exhibited the behavior of a biosynthetic intermediate since it formed in advance of the final product A2E and was consumed as A2E accumulated. Moreover, under deoxygenated conditions, conversion to the aromatic pyridinium bisretinoid was inhibited. Taken together, these findings indicate that A2E biosynthesis involves the oxidation of a dihydropyridinium intermediate dihydro-A2PE. An understanding of the biosynthetic pathways of retinal pigment epithelial lipofuscin pigments is critical to the development of therapies for macular degeneration that are based on limiting the formation of these damaging compounds.
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Affiliation(s)
- So R. Kim
- Department of Ophthalmology, Columbia University, New York, New York 10032
| | - Jiangtao He
- Department of Chemistry, Columbia University, New York, New York 10032
| | - Emiko Yanase
- Department of Ophthalmology, Columbia University, New York, New York 10032
- Department of Chemistry, Columbia University, New York, New York 10032
| | - Young P. Jang
- Department of Ophthalmology, Columbia University, New York, New York 10032
| | - Nina Berova
- Department of Chemistry, Columbia University, New York, New York 10032
| | - Koji Nakanishi
- Department of Chemistry, Columbia University, New York, New York 10032
| | - Janet R. Sparrow
- Department of Ophthalmology, Columbia University, New York, New York 10032
- Department of Pathology and Cell Biology , Columbia University, New York, New York 10032
- To whom correspondence should be addressed. 630 W. 168 Street, New York NY 10021; Phone: (212) 305−9944. Fax: (212) 305−9638. E-mail:
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33
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Nemykin VN, Olsen JG, Perera E, Basu P. Synthesis, molecular and electronic structure, and TDDFT and TDDFT-PCM study of the solvatochromic properties of (Me2Pipdt)Mo(CO)4 complex (Me2Pipdt = N,N'-dimethylpiperazine-2,3-dithione). Inorg Chem 2007; 45:3557-68. [PMID: 16634586 DOI: 10.1021/ic051653p] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis, spectroscopic, and structural characterization of the (Me2Pipdt)Mo(CO)4 complex (Me2Pipdt = N,N'-piperazine-2,3-dithione) are presented in this paper. The title complex crystallizes in the P2(1)/n space group with a = 25.541(3) A, b = 10.3936(14) A, c = 10.9012(12) A, beta = 92.261(9) degrees , V = 2891.6(6) A(3), and Z = 8. Gas- and solution-phase structural and electronic features of (Me2Pipdt)Mo(CO)4 and Me2Pipdt have been investigated using density functional theory. The molecular structure underscores the flexibility of the NC(S)C(S)N fragment in both the free ligand and the metal complex. On the basis of structural, spectroscopic, and theoretical results, the bidentate ligand in (Me2Pipdt)Mo(CO)4 is considered to be in the dithione, not dithiolate, form. Time-dependent density functional theory has been used for the investigation of the excited states and solvatochromic properties of (Me2Pipdt)Mo(CO)4. The calculated vertical excitation energies in solution are consistent with the experimental data, showing that the metal-to-ligand charge-transfer transitions, in both the visible and UV regions, dominate over the ligand-based pi-pi transitions.
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Affiliation(s)
- Victor N Nemykin
- Department of Chemistry and Biochemistry, University of Minnesota at Duluth, Duluth, Minnesota 55812, USA.
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34
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Yang G, Fang L, Tan K, Shi S, Su Z, Wang R. Quantum Chemical Study of Structures, Electronic Spectrum, and Nonlinear Optical Properties of Gold−Pentacene Complexes. Organometallics 2007. [DOI: 10.1021/om060955b] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Guochun Yang
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, People's Republic of China, and College of Environment Ecosystem and Engineering, Changchun University, Changchun 130022, Jilin, People's Republic of China
| | - Liang Fang
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, People's Republic of China, and College of Environment Ecosystem and Engineering, Changchun University, Changchun 130022, Jilin, People's Republic of China
| | - Ke Tan
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, People's Republic of China, and College of Environment Ecosystem and Engineering, Changchun University, Changchun 130022, Jilin, People's Republic of China
| | - Shaoqing Shi
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, People's Republic of China, and College of Environment Ecosystem and Engineering, Changchun University, Changchun 130022, Jilin, People's Republic of China
| | - Zhongmin Su
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, People's Republic of China, and College of Environment Ecosystem and Engineering, Changchun University, Changchun 130022, Jilin, People's Republic of China
| | - Rongshun Wang
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, People's Republic of China, and College of Environment Ecosystem and Engineering, Changchun University, Changchun 130022, Jilin, People's Republic of China
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35
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Jaworska M. DFT calculations for model diimine-iron complexes with nitric oxide and water ligands. INORG CHEM COMMUN 2006. [DOI: 10.1016/j.inoche.2005.11.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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36
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On the stability of the π-allyl intermediate in molybdenum-catalyzed asymmetric alkylations. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.tetasy.2006.01.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Menconi G, Kaltsoyannis N. Time dependent DFT study of the electronic transition energies of RuO4 and OsO4. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.08.092] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Nemykin VN, Basu P. Oxygen Atom Transfer Reactivity from a Dioxo-Mo(VI) Complex to Tertiary Phosphines: Synthesis, Characterization, and Structure of Phosphoryl Intermediate Complexes. Inorg Chem 2005; 44:7494-502. [PMID: 16212375 DOI: 10.1021/ic0508324] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The oxygen atom transfer (OAT) reactivity of TpMoO2Cl with PMe3, PEt3, and PPhMe2 (where Tp = hydrotris(3,5-dimethylpyrazol-1-yl)borate) has been investigated. The OAT reactions proceed through a diamagnetic Mo(IV) phosphoryl intermediate complex of general formula TpMoOCl(OPR3) (OPR3 = OPMe3, OPEt3, OPPhMe2), which have been isolated and characterized by 1H and 31P NMR, UV-visible, and infrared spectroscopies and electrospray ionization mass spectrometry. Solid-state crystal structures of TpMoOCl(OPMe3) and TpMoOCl(OPPhMe2) are also reported, the oxygen-to-phosphorus distances agree with a double-bond formulation and a single bond between the metal and the phosphoryl oxygen atom. The stability of the phosphoryl intermediate complexes depends on the steric properties of the coordinated phosphine-oxides. These intermediate complexes have been converted to solvent-coordinated species, TpMoOCl(solv) (solv = acetonitrile or dmf), and the coordinated solvents exchange with the bulk solvent.
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Affiliation(s)
- Victor N Nemykin
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, USA
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Wang F, Ziegler * T. Excitation energies of some d1systems calculated using time-dependent density functional theory: an implementation of open-shell TDDFT theory for doublet–doublet excitations. Mol Phys 2004. [DOI: 10.1080/0026897042000275080] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Waters T, Wang XB, Yang X, Zhang L, O'Hair RAJ, Wang LS, Wedd AG. Photoelectron spectroscopy of the doubly-charged anions [MIVO(mnt)2]2- (M = Mo, W; mnt = S2C2(CN)2(2-): access to the ground and excited states of the [MVO(mnt)2]- anion. J Am Chem Soc 2004; 126:5119-29. [PMID: 15099095 DOI: 10.1021/ja039652o] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Photodetachment photoelectron spectroscopy was used to investigate the electronic structure of the doubly charged complexes [MIVO(mnt)2]2- (M = Mo, W; mnt = 1,2-dicyanoethenedithiolato). These dianions are stable in the gas phase and are minimal models for the active sites of the dimethyl sulfoxide reductase family of molybdenum enzymes and of related tungsten enzymes. Adiabatic and vertical electron binding energies for both species were measured, providing detailed information about molecular orbital energy levels of the parent dianions as well as the ground and excited states of the product anions [MVO(mnt)2]-. Density functional theory calculations were used to assist assignment of the detachment features. Differences in energy between these features provided the energies of ligand-to-metal charge-transfer transitions from S(pi) and S(sigma) molecular orbitals to the singly occupied metal-based orbital of the products [MVO(mnt)2]-. These unique data for the M(V) species were obtained at the C(2)(v)() geometry of the parent M(IV) dianions. However, theoretical calculations and available condensed phase data suggested that a geometry featuring differentially folded dithiolene ligands (Cs point symmetry) was slightly lower in energy. The driving force for ligand folding is a favorable covalent interaction between the singly occupied metal-based molecular orbital (a1 in C2v) point symmetry; highest occupied molecular orbital (HOMO)) and the least stable of the occupied sulfur-based molecular orbitals (b1 in C2v point symmetry, HOMO-1) that is only possible upon reduction to the lower symmetry. This ligand folding induces a large increase in the intensity predicted for the a' S(pi) --> a' dx2 - y2 charge-transfer transition originating from the HOMO-2 of [MVO(mnt)2](-) under Cs point symmetry. Electronic absorption spectra are available for the related species [MoVO(bdt)2]- (bdt = 1,2-benzenedithiolato) and for the oxidized form of dimethyl sulfoxide reductase. The intense absorptions at approximately 1.7 eV have been assigned previously to S(sigma) --> Mo transitions, assuming C2v geometry. The present work indicates that the alternative a' S(pi) --> a' dx2 - y2 of Cs geometry must be considered. Overall, this study confirms that the electronic structure of the M-dithiolene units are exquisitely sensitive to dithiolene ligand folding, reinforcing the proposal that these units are tunable conduits for electron transfer in enzyme systems.
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Affiliation(s)
- Tom Waters
- School of Chemistry, University of Melbourne, Victoria, Australia, 3010
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Excitation Energies of Metal Complexes with Time-dependent Density Functional Theory. PRINCIPLES AND APPLICATIONS OF DENSITY FUNCTIONAL THEORY IN INORGANIC CHEMISTRY I 2004. [DOI: 10.1007/b97937] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Basu P, Nemykin VN, Sengar RS. Syntheses, Spectroscopy, and Redox Chemistry of Encapsulated Oxo−Mo(V) Centers: Implications for Pyranopterin-Containing Molybdoenzymes. Inorg Chem 2003; 42:7489-501. [PMID: 14606844 DOI: 10.1021/ic034821r] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Coordination by at least four sulfur donors to an embedded molybdenum center has been found to be a common feature in the crystal structures of many mononuclear molybdenum enzymes. In an effort to model embedded molybdenum centers, we have synthesized dendritic thiolate ligands and their oxo-molybdenum complexes containing a [Mo(V)OS(4)](-) core. These compounds have been isolated in pure form as blue solids or gummy materials, and the molecular nature of these compounds has been confirmed by electrospray ionization mass spectrometry and infrared, electron paramagnetic resonance, and UV-vis spectroscopies. The dendritic complexes exhibit little variation in their broad S --> Mo charge transfer band (lambda(max) approximately 600 nm; epsilon approximately 6000 M(-)(1) cm(-)(1)), Mo=O vibration energy (941-943 cm(-)(1)), and EPR g-values (g( parallel ) approximately 2.02; g( perpendicular ) approximately 1.98; g(av) approximately 1.99). The spectroscopic data confirm the integrity of the square pyramidal [Mo(V)OS(4)](-) core with little geometric distortions, suggesting that the electronic structure at the metal center is not perturbed by the ligand architecture. The electronic structure of these complexes, calculated by the density functional theory, demonstrates a similar composition of the HOMO. In complexes 6 and 7a, the energy of the HOMO orbital might be modulated by the difference in the electronic structure of the ligands. The Mo(V/IV) reduction potentials vary as a function of the dielectric constant and the donor number of the solvent. The kinetics of the reduction is influenced by the reorganization of the geometry and the encapsulating effect. We suggest that protein structure imposed microenvironments may control the dielectric properties and hence the redox properties of the metal center in many metallobiomolecules.
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Affiliation(s)
- Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, USA.
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