1
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Elvers BJ, Krewald V, Schulzke C, Fischer C. Reduction induced S-nucleophilicity in mono-dithiolene molybdenum complexes - in situ generation of sulfonium ligands. Chem Commun (Camb) 2021; 57:12615-12618. [PMID: 34755726 DOI: 10.1039/d1cc05335c] [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
The reduction of a molybdenum monodithiolene complex, [Mo(CO)2(dt)(dppe)], in the presence of dichloromethane leads to the transfer of CH2 to sulfur and respective sulfonium species. Detailed analytical and mechanistical spectroscopic and electrochemical studies reveal the reasons for the unexpected formation and composition of the very unusual resultant complexes to be electronic-energetic in nature.
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Affiliation(s)
- Benedict J Elvers
- Universität Greifswald, Institut für Biochemie, Felix-Hausdorff-Str. 4, Greifswald, Germany.
| | - Vera Krewald
- Technische Universität Darmstadt, Fachbereich Chemie, Theoretische Chemie, Alarich-Weiss-Str. 4, 64287 Darmstadt, Germany.
| | - Carola Schulzke
- Universität Greifswald, Institut für Biochemie, Felix-Hausdorff-Str. 4, Greifswald, Germany.
| | - Christian Fischer
- Universität Greifswald, Institut für Biochemie, Felix-Hausdorff-Str. 4, Greifswald, Germany.
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2
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Basu P, Colston KJ, Mogesa B. Dithione, the antipodal redox partner of ene-1,2-dithiol ligands and their metal complexes. Coord Chem Rev 2020; 409:213211. [PMID: 38094102 PMCID: PMC10718511 DOI: 10.1016/j.ccr.2020.213211] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Defining the oxidation state of the central atom in a coordination compound is fundamental in understanding the electronic structure and provides a starting point for elucidating molecular properties. The presence of non-innocent ligand(s) can obscure the oxidation state of the central atom as the ligand contribution to the electronic structure is difficult to ascertain. Redox-active ligands, such as dithiolene ligands, are well known non-innocent ligands that can exist in both a fully reduced (Dt2-) and fully oxidized (Dt0) states. Complexes containing the fully oxidized dithione state of the ligand are uncommon and only a few have been completely characterized. Dithione ligands are of interest due to their electron-deficient nature and ability to act as an electron acceptor for more electron-rich moieties, such as other dithiolene ligands or metal centers. This article focuses the syntheses, structures, and metal coordination, particularly coordination compounds, of dithione ligands. Various examples of mono, bis, and tris dithione complexes are discussed.
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Affiliation(s)
- Partha Basu
- Department of Chemistry and Chemical Biology, IUPUI, Indianapolis, IN 46202, United States
| | - Kyle J. Colston
- Department of Chemistry and Chemical Biology, IUPUI, Indianapolis, IN 46202, United States
| | - Benjamin Mogesa
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282, United States
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3
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Helland SD, Chang AS, Lee KW, Hutchison PS, Brennessel WW, Eckenhoff WT. Synthesis and Characterization of Strongly Solvatochromic Molybdenum(III) Complexes. Inorg Chem 2020; 59:705-716. [PMID: 31860297 DOI: 10.1021/acs.inorgchem.9b02955] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of seven molybdenum(III) complexes with the general formula of [Mo(diimine)Cl4]- were synthesized and characterized by X-ray diffraction, IR, cyclic voltammetry (CV), and UV-vis. The complexes were discovered to be highly solvatochromic, showing shifts in λmax between ∼120 and 170 nm in solvents ranging from water to acetone. Varying the substituents on the diimine ligand influenced the absorption energy such that electron-withdrawing groups induced a red shift while electron-donating groups exhibited the opposite effect. The complexes were surprisingly stable in both acidic and basic solutions, and in the case where carboxylic acid substituents were present, additional shifts in the absorption maxima were observed, corresponding to the state of protonation of these groups. Both the MoIV/III and MoIII/II redox couples were observed in CV experiments and were complemented with density functional theory (DFT) calculations.
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Affiliation(s)
- Sarah D Helland
- Department of Chemistry , Rhodes College , 2000 North Parkway , Memphis , Tennessee 38112 , United States
| | - Alison S Chang
- Department of Chemistry , Rhodes College , 2000 North Parkway , Memphis , Tennessee 38112 , United States
| | - Keren W Lee
- Department of Chemistry , Rhodes College , 2000 North Parkway , Memphis , Tennessee 38112 , United States
| | - Phillips S Hutchison
- Department of Chemistry , Rhodes College , 2000 North Parkway , Memphis , Tennessee 38112 , United States
| | - William W Brennessel
- Department of Chemistry , University of Rochester , 120 Trustee Road , Rochester , New York 14627 , United States
| | - William T Eckenhoff
- Department of Chemistry , Rhodes College , 2000 North Parkway , Memphis , Tennessee 38112 , United States
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4
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Elvers BJ, Schulzke C, Fischer C. Photochemical Unmasking of 1,3‐Dithiol‐2‐ones: An Alternative Route to Heteroleptic Dithiolene Complexes from Low‐Valent Molybdenum and Tungsten Precursors. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900124] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Benedict J. Elvers
- Institute for Biochemistry Universität Greifswald Felix‐Hausdorffstr.4 17487 Greifswald Germany
| | - Carola Schulzke
- Institute for Biochemistry Universität Greifswald Felix‐Hausdorffstr.4 17487 Greifswald Germany
| | - Christian Fischer
- Institute for Biochemistry Universität Greifswald Felix‐Hausdorffstr.4 17487 Greifswald Germany
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5
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Chrysochos N, Ahmadi M, Wahlefeld S, Rippers Y, Zebger I, Mroginski MA, Schulzke C. Comparison of molybdenum and rhenium oxo bis-pyrazine-dithiolene complexes - in search of an alternative metal centre for molybdenum cofactor models. Dalton Trans 2019; 48:2701-2714. [PMID: 30720825 DOI: 10.1039/c8dt04237c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A pair of structurally precise analogues of molybdenum and rhenium complexes, [Et4N]/K2[MoO(prdt)2] and K[ReO(prdt)2] (prdt = pyrazine-2,3-dithiolene), were synthesized. These complexes serve as structural models for the active sites of bacterial molybdenum cofactor containing enzymes. They were comprehensively characterized and investigated by NMR, computationally supported IR and resonance Raman spectroscopy, cyclic voltammetry, mass spectrometry, elemental analysis and single-crystal X-ray diffraction. All compiled data are discussed in the context of comparing chemical and electronic structures and consequences thereof. This study constitutes the first investigation of a potential alternative Moco model system bearing rhenium as the central metal in an identical coordination environment to its molybdenum analogue. Structural evaluation revealed a slightly stronger M[double bond, length as m-dash]O bond in the rhenium complex in accordance with spectroscopic results, i.e. observed bond strengths. Thermodynamic parameters for the redox processes MoIV ↔ MoV and ReIV ↔ ReV were obtained by temperature dependent cyclic voltammetry. In contrast to molybdenum, rhenium loses entropy upon reduction and its redox potential is more temperature sensitive, indicating more significant differences than the respective diagonal relationship between the two metals in the periodic table might suggest and questioning rhenium's suitability as a functional artificial active site metal.
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Affiliation(s)
- Nicolas Chrysochos
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Straße 4, 17487 Greifswald, Germany.
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6
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Goodwin CAP, Réant BLL, Kragskow JGC, DiMucci IM, Lancaster KM, Mills DP, Sproules S. Heteroleptic samarium(iii) halide complexes probed by fluorescence-detected L 3-edge X-ray absorption spectroscopy. Dalton Trans 2018; 47:10613-10625. [PMID: 29790545 PMCID: PMC6083822 DOI: 10.1039/c8dt01452c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The novel series of heteroleptic Sm(iii) halide complexes provides the backdrop for a fluorescence-detected Lα1 X-ray absorption spectroscopic study.
The addition of various oxidants to the near-linear Sm(ii) complex [Sm(N††)2] (1), where N†† is the bulky bis(triisopropylsilyl)amide ligand {N(SiiPr3)2}, afforded a family of heteroleptic three-coordinate Sm(iii) halide complexes, [Sm(N††)2(X)] (X = F, 2-F; Cl, 2-Cl; Br, 2-Br; I, 2-I). In addition, the trinuclear cluster [{Sm(N††)}3(μ2-I)3(μ3-I)2] (3), which formally contains one Sm(ii) and two Sm(iii) centres, was isolated during the synthesis of 2-I. Complexes 2-X are remarkably stable towards ligand redistribution, which is often a facile process for heteroleptic complexes of smaller monodentate ligands in lanthanide chemistry, including the related bis(trimethylsilyl)amide {N(SiMe3)2} (N′′). Complexes 2-X and 3 have been characterised by single crystal X-ray diffraction, elemental analysis, multinuclear NMR, FTIR and electronic spectroscopy. The Lα1 fluorescence-detected X-ray absorption spectra recorded at the Sm L3-edge for 2-X exhibited a resolved pre-edge peak defined as an envelope of quadrupole-allowed 2p → 4f transitions. The X-ray absorption spectral features were successfully reproduced using time-dependent density functional theoretical (TD-DFT) calculations that synergistically support the experimental observations as well as the theoretical model upon which the electronic structure and bonding in these lanthanide complexes is derived.
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Affiliation(s)
- Conrad A P Goodwin
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Benjamin L L Réant
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Jon G C Kragskow
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Ida M DiMucci
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York, 14853, USA.
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York, 14853, USA.
| | - David P Mills
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Stephen Sproules
- WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ, UK.
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7
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Arumugam K, Selvachandran M, Obanda A, Shaw MC, Chandrasekaran P, Caston Good SL, Mague JT, Sproules S, Donahue JP. Redox-Active Metallodithiolene Groups Separated by Insulating Tetraphosphinobenzene Spacers. Inorg Chem 2018. [PMID: 29533607 DOI: 10.1021/acs.inorgchem.8b00201] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Compounds of the type [(S2C2R2)M(μ-tpbz)M(S2C2R2)] (R = CN, Me, Ph, p-anisyl; M = Ni, Pd, Pt; tpbz = 1,2,4,5-tetrakis(diphenylphosphino)benzene) have been prepared by transmetalation with [(S2C2R2)SnR'2] reagents, by direct displacement of dithiolene ligand from [M(S2C2R2)2] with 0.5 equiv of tpbz, or by salt metathesis using Na2[S2C2(CN)2] in conjunction with X2M(μ-tpbz)MX2 (X = halide). X-ray crystallography reveals a range of topologies (undulating, chair, bowed) for the (S2C2)M(P2C6P2)M(S2C2) core. The [(S2C2R2)M(μ-tpbz)M(S2C2R2)] (R = Me, Ph, p-anisyl) compounds support reversible or quasireversible oxidations corresponding to concurrent oxidation of the dithiolene terminal ligands from ene-1,2-dithiolates to radical monoanions, forming [(-S•SC2R2)M(μ-tpbz)M(-S•SC2R2)]2+. The R = Ph and p-anisyl compounds support a second, reversible oxidation of the dithiolene ligands to their α-dithione form. In contrast, [(S2C2(CN)2)Ni(tpbz)Ni(S2C2(CN)2)] sustains only reversible, metal-centered reductions. Spectroscopic examination of [(-S•SC2( p-anisyl)2)Ni(μ-tpbz)Ni(-S•SC2( p-anisyl)2)]2+ by EPR reveals a near degenerate singlet-triplet ground state, with spectral simulation revealing a remarkably small dipolar coupling constant of 18 × 10-4 cm-1 that is representative of an interspin distance of 11.3 Å. This weak interaction is mediated by the rigid tpbz ligand, whose capacity to electronically insulate is an essential quality in the development of molecular-based spintronic devices.
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Affiliation(s)
- Kuppuswamy Arumugam
- Department of Chemistry , Wright State University , 3640 Colonel Glenn Highway , Dayton , Ohio 45435-0001 , United States
| | - Malathy Selvachandran
- Department of Chemistry , Tulane University , 6400 Freret Street , New Orleans , Louisiana 70118-5698 , United States
| | - Antony Obanda
- Department of Chemistry , Tulane University , 6400 Freret Street , New Orleans , Louisiana 70118-5698 , United States
| | - Mohamed C Shaw
- Department of Chemistry , Tulane University , 6400 Freret Street , New Orleans , Louisiana 70118-5698 , United States
| | | | - Sonya L Caston Good
- Department of Chemistry , Texas Southern University , 1300 Cleburne Street , Houston , Texas 77004 , United States
| | - Joel T Mague
- Department of Chemistry , Tulane University , 6400 Freret Street , New Orleans , Louisiana 70118-5698 , United States
| | - Stephen Sproules
- WestCHEM, School of Chemistry , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - James P Donahue
- Department of Chemistry , Tulane University , 6400 Freret Street , New Orleans , Louisiana 70118-5698 , United States
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8
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Attar S, Espa D, Artizzu F, Mercuri ML, Serpe A, Sessini E, Concas G, Congiu F, Marchiò L, Deplano P. A Platinum-Dithiolene Monoanionic Salt Exhibiting Multiproperties, Including Room-Temperature Proton-Dependent Solution Luminescence. Inorg Chem 2016; 55:5118-26. [PMID: 27163727 DOI: 10.1021/acs.inorgchem.5b02491] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The platinum salt C[PtL2], where C = [(R)-Ph(Me)HC*-NMe3](+) and [PtL2](-) = radical monoanion based on [4', 5': 5, 6][1, 4]dithiino[2,3-b]quinoxaline-1',3'dithiolato, shows a variety of properties both in solution and in the solid state thanks to the electronic and/or structural features of the ligand. The complex crystallizes in the chiral space group P1 due to the presence of the enantiopure cation (R)-Ph(Me)HC*-NMe3(+), and it shows paramagnetic behavior relatable to the [PtL2](-) radical monoanion. This anionic complex is redox active and shows a strong near-infrared absorbance peak at 1085 nm tunable with the oxidation state of the complex. This complex exhibits a proton-dependent emission at 572 nm in solution at room temperature. The excitation band corresponds to the HOMO-1 (π-orbitals of the S2C2S2 system) → LUMO (π-orbitals of the quinoxaline and benzene-like moieties) transition suggesting that emission is mainly ligand centered in character. The luminescent properties are highly unusual, since the emission falls well above the energy of the lowest energy absorption (anti-Kasha behavior). Joint experimental and density functional theory (DFT) and time-dependent DFT studies are discussed to provide a satisfactory structure/property relationship.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Luciano Marchiò
- Dipartimento di Chimica, Università di Parma , Parco Area delle Scienze 17A, I43124 Parma, Italy
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9
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White JL, Baruch MF, Pander JE, Hu Y, Fortmeyer IC, Park JE, Zhang T, Liao K, Gu J, Yan Y, Shaw TW, Abelev E, Bocarsly AB. Light-Driven Heterogeneous Reduction of Carbon Dioxide: Photocatalysts and Photoelectrodes. Chem Rev 2015; 115:12888-935. [DOI: 10.1021/acs.chemrev.5b00370] [Citation(s) in RCA: 1148] [Impact Index Per Article: 127.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- James L. White
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
| | - Maor F. Baruch
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
| | - James E. Pander
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
| | - Yuan Hu
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
| | - Ivy C. Fortmeyer
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
| | - James Eujin Park
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
| | - Tao Zhang
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
| | - Kuo Liao
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
| | - Jing Gu
- Chemical
and Materials Science Center, National Renewable Energy Laboratory
, Golden, Colorado
80401, United States
| | - Yong Yan
- Chemical
and Materials Science Center, National Renewable Energy Laboratory
, Golden, Colorado
80401, United States
| | - Travis W. Shaw
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
| | - Esta Abelev
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
| | - Andrew B. Bocarsly
- Department
of Chemistry, Princeton University
, Princeton, New Jersey
08544, United States
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10
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Hasenaka Y, Okamura TA, Tatsumi M, Inazumi N, Onitsuka K. Behavior of anionic molybdenum(IV, VI) and tungsten(IV, VI) complexes containing bulky hydrophobic dithiolate ligands and intramolecular NH···S hydrogen bonds in nonpolar solvents. Dalton Trans 2015; 43:15491-502. [PMID: 25190301 DOI: 10.1039/c4dt01646g] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molybdenum(IV, VI) and tungsten(IV, VI) complexes, (Et4N)2[M(IV)O{1,2-S2-3,6-(RCONH)2C6H2}2] and (Et4N)2[M(VI)O2{1,2-S2-3,6-(RCONH)2C6H2}2] (M = Mo, W; R = (4-(t)BuC6H4)3C), with bulky hydrophobic dithiolate ligands containing NH···S hydrogen bonds were synthesized. These complexes are soluble in nonpolar solvents like toluene, which allows the detection of unsymmetrical coordination structures and elusive intermolecular interactions in solution. The (1)H NMR spectra of the complexes in toluene-d8 revealed an unsymmetrical coordination structure, and proximity of the counterions to the anion moiety was suggested at low temperatures. The oxygen-atom-transfer reaction between the molybdenum(IV) complex and Me3NO in toluene was considerably accelerated in nonpolar solvents, and this increase was attributed to the favorable access of the substrate to the active center in the hydrophobic environment.
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Affiliation(s)
- Yuki Hasenaka
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
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11
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Majumdar A. Structural and functional models in molybdenum and tungsten bioinorganic chemistry: description of selected model complexes, present scenario and possible future scopes. Dalton Trans 2015; 43:8990-9003. [PMID: 24798698 DOI: 10.1039/c4dt00631c] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A brief description about some selected model complexes in molybdenum and tungsten bioinorganic chemistry is provided. The synthetic strategies involved and their limitations are discussed. Current status of molybdenum and tungsten bioinorganic modeling chemistry is presented briefly and synthetic problems associated therein are analyzed. Possible future directions which may expand the scope of modeling chemistry are suggested.
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Affiliation(s)
- Amit Majumdar
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
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12
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Yan Y, Lee JS, Ruddy DA. Structure–Function Relationships for Electrocatalytic Water Oxidation by Molecular [Mn12O12] Clusters. Inorg Chem 2015; 54:4550-5. [DOI: 10.1021/acs.inorgchem.5b00398] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yong Yan
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - John S. Lee
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Daniel A. Ruddy
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
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13
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Yan Y, Mague JT, Donahue JP, Sproules S. Unprecedented spin localisation in a metal–metal bonded dirhenium complex. Chem Commun (Camb) 2015; 51:5482-5. [DOI: 10.1039/c4cc09397f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
[N(n-Bu)4]3[Re2(mnt)5] is the first class I, valence localized dirhenium(iii,iv) compound, with a metal–metal bond.
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Affiliation(s)
- Yong Yan
- Department of Chemistry
- Tulane University
- New Orleans
- USA
| | - Joel T. Mague
- Department of Chemistry
- Tulane University
- New Orleans
- USA
| | | | - Stephen Sproules
- WestCHEM
- School of Chemistry
- University of Glasgow
- Glasgow G12 8QQ
- UK
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14
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Jayarathne U, Chandrasekaran P, Greene A, Mague JT, DeBeer S, Lancaster KM, Sproules S, Donahue JP. X-ray absorption spectroscopy systematics at the tungsten L-edge. Inorg Chem 2014; 53:8230-41. [PMID: 25068843 PMCID: PMC4139175 DOI: 10.1021/ic500256a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Indexed: 01/08/2023]
Abstract
A series of mononuclear six-coordinate tungsten compounds spanning formal oxidation states from 0 to +VI, largely in a ligand environment of inert chloride and/or phosphine, was interrogated by tungsten L-edge X-ray absorption spectroscopy. The L-edge spectra of this compound set, comprised of [W(0)(PMe3)6], [W(II)Cl2(PMePh2)4], [W(III)Cl2(dppe)2][PF6] (dppe = 1,2-bis(diphenylphosphino)ethane), [W(IV)Cl4(PMePh2)2], [W(V)(NPh)Cl3(PMe3)2], and [W(VI)Cl6], correlate with formal oxidation state and have usefulness as references for the interpretation of the L-edge spectra of tungsten compounds with redox-active ligands and ambiguous electronic structure descriptions. The utility of these spectra arises from the combined correlation of the estimated branching ratio of the L3,2-edges and the L1 rising-edge energy with metal Zeff, thereby permitting an assessment of effective metal oxidation state. An application of these reference spectra is illustrated by their use as backdrop for the L-edge X-ray absorption spectra of [W(IV)(mdt)2(CO)2] and [W(IV)(mdt)2(CN)2](2-) (mdt(2-) = 1,2-dimethylethene-1,2-dithiolate), which shows that both compounds are effectively W(IV) species even though the mdt ligands exist at different redox levels in the two compounds. Use of metal L-edge XAS to assess a compound of uncertain formulation requires: (1) Placement of that data within the context of spectra offered by unambiguous calibrant compounds, preferably with the same coordination number and similar metal ligand distances. Such spectra assist in defining upper and/or lower limits for metal Zeff in the species of interest. (2) Evaluation of that data in conjunction with information from other physical methods, especially ligand K-edge XAS. (3) Increased care in interpretation if strong π-acceptor ligands, particularly CO, or π-donor ligands are present. The electron-withdrawing/donating nature of these ligand types, combined with relatively short metal-ligand distances, exaggerate the difference between formal oxidation state and metal Zeff or, as in the case of [W(IV)(mdt)2(CO)2], exert the subtle effect of modulating the redox level of other ligands in the coordination sphere.
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Affiliation(s)
- Upul Jayarathne
- Department
of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Perumalreddy Chandrasekaran
- Department
of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
- Department
of Chemistry and Biochemistry, Lamar University, Beaumont, Texas 77710, United States
| | - Angelique
F. Greene
- Department
of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Joel T. Mague
- Department
of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Serena DeBeer
- Department
of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
- Max-Planck-Institut
für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470, Mülheim an der Ruhr, Germany
| | - Kyle M. Lancaster
- Department
of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Stephen Sproules
- WestCHEM,
School of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - James P. Donahue
- Department
of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
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15
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Chandrasekaran P, Greene AF, Lillich K, Capone S, Mague JT, DeBeer S, Donahue JP. A Structural and Spectroscopic Investigation of Octahedral Platinum Bis(dithiolene)phosphine Complexes: Platinum Dithiolene Internal Redox Chemistry Induced by Phosphine Association. Inorg Chem 2014; 53:9192-205. [DOI: 10.1021/ic501273b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- P. Chandrasekaran
- Department of Chemistry and Biochemistry, Lamar University, Beaumont, Texas 77710, United States
| | - Angelique F. Greene
- Department of Chemistry, Tulane University, 6400
Freret Street, New Orleans, Louisiana 70118, United States
| | - Karen Lillich
- Department of Chemistry, Tulane University, 6400
Freret Street, New Orleans, Louisiana 70118, United States
| | - Stephen Capone
- Department of Chemistry, Tulane University, 6400
Freret Street, New Orleans, Louisiana 70118, United States
| | - Joel T. Mague
- Department of Chemistry, Tulane University, 6400
Freret Street, New Orleans, Louisiana 70118, United States
| | - Serena DeBeer
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse
34−36, D-45470 Mülheim an der Ruhr, Germany
| | - James P. Donahue
- Department of Chemistry, Tulane University, 6400
Freret Street, New Orleans, Louisiana 70118, United States
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Yan Y, Keating C, Chandrasekaran P, Jayarathne U, Mague JT, DeBeer S, Lancaster KM, Sproules S, Rubtsov IV, Donahue JP. Ancillary ligand effects upon dithiolene redox noninnocence in tungsten bis(dithiolene) complexes. Inorg Chem 2013; 52:6743-51. [PMID: 23675834 DOI: 10.1021/ic4009174] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An expanded set of compounds of the type [W(S2C2Me2)2L1L2](n) (n = 0: L1 = L2 = CO, 1; L1 = L2 = CN(t)Bu, 2; L1 = CO, L2 = carbene, 3; L1 = CO, L2 = phosphine, 4; L1 = L2 = phosphine, 5. n = 2-: L1 = L2 = CN(-), [6](2-)) has been synthesized and characterized. Despite isoelectronic formulations, the compound set reveals gradations in the dithiolene ligand redox level as revealed by intraligand bond lengths, υ(CCchelate), and rising edge energies in the sulfur K-edge X-ray absorption spectra (XAS). Differences among the terminal series members, 1 and [6](2-), are comparable to differences seen in homoleptic dithiolene complexes related by full electron transfer to/from a dithiolene-based MO. The key feature governing these differences is the favorable energy of the CO π* orbitals, which are suitably positioned to overlap with tungsten d orbitals and exert an oxidizing effect on both metal and dithiolene ligand via π-backbonding. The CN(-) π* orbitals are too high in energy to mix effectively with tungsten and thus leave the filled dithiolene π* orbitals unperturbed. This work shows how, and the degree to which, the redox level of a noninnocent ligand can be modulated by the choice of ancillary ligands(s).
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Affiliation(s)
- Yong Yan
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118-5698, USA
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