1
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Quiroz M, Jana M, Liu K, Bhuvanesh N, Hall MB, Darensbourg MY. Site specific redox properties in ligand differentiated di-nickel complexes inspired by the acetyl CoA synthase active site. Dalton Trans 2024; 53:7414-7423. [PMID: 38591102 DOI: 10.1039/d4dt00306c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Bimetallic transition metal complexes with site-specific redox properties offer a versatile platform for understanding electron polarization, intramolecular electron transfer processes, and customizing electronic and magnetic properties that might impact reactivity and catalyst design. Inspired by the dissymmetric nickel sites in the Acetyl CoA Synthase (ACS) Active Site, three new bimetallic Ni(N2S2)-Ni(S2C2R2) complexes based on Ni(N2S2) metalloligand donor synthons, Nid, in mimicry of the nickel site distal to the redox-active iron sulfur cluster of ACS, and nickel dithiolene receiver units, designated as Nip, the nickel proximal to the 4Fe4S cluster, were combined to explore the influence of ligand environment on electronic structure and redox properties of each unit. The combination of synthons gave a matrix of three S-bridged dinickel complexes, characterized by X-ray crystallography, and appropriate spectroscopies. Computational modeling is connected to the electronic characteristics of the nickel donor and receiver units. This study demonstrated the intricacies of identifying sites of electrochemical redox processes, within multi-metallic systems containing non-innocent ligands.
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Affiliation(s)
- Manuel Quiroz
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, USA.
| | - Manish Jana
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, USA.
| | - Kaiyang Liu
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, USA.
| | - Nattamai Bhuvanesh
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, USA.
| | - Michael B Hall
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, USA.
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2
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Quiroz M, Darensbourg MY. Development of (NO)Fe(N 2S 2) as a Metallodithiolate Spin Probe Ligand: A Case Study Approach. Acc Chem Res 2024; 57:831-844. [PMID: 38416694 PMCID: PMC10979402 DOI: 10.1021/acs.accounts.3c00667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 03/01/2024]
Abstract
ConspectusThe ubiquity of sulfur-metal connections in nature inspires the design of bi- and multimetallic systems in synthetic inorganic chemistry. Common motifs for biocatalysts developed in evolutionary biology include the placement of metals in close proximity with flexible sulfur bridges as well as the presence of π-acidic/delocalizing ligands. This Account will delve into the development of a (NO)Fe(N2S2) metallodithiolate ligand that harnesses these principles. The Fe(NO) unit is the centroid of a N2S2 donor field, which as a whole is capable of serving as a redox-active, bidentate S-donor ligand. Its paramagnetism as well as the ν(NO) vibrational monitor can be exploited in the development of new classes of heterobimetallic complexes. We offer four examples in which the unpaired electron on the {Fe(NO)}7 unit is spin-paired with adjacent paramagnets in proximal and distal positions.First, the exceptional stability of the (NO)Fe(N2S2)-Fe(NO)2 platform, which permits its isolation and structural characterization at three distinct redox levels, is linked to the charge delocalization occurring on both the Fe(NO) and the Fe(NO)2 supports. This accommodates the formation of a rare nonheme {Fe(NO)}8 triplet state, with a linear configuration. A subsequent FeNi complex, featuring redox-active ligands on both metals (NO on iron and dithiolene on nickel), displayed unexpected physical properties. Our research showed good reversibility in two redox processes, allowing isolation in reduced and oxidized forms. Various spectroscopic and crystallographic analyses confirmed these states, and Mössbauer data supported the redox change at the iron site upon reduction. Oxidation of the complex produced a dimeric dication, revealing an intriguing magnetic behavior. The monomer appears as a spin-coupled diradical between {Fe(NO)}7 and the nickel dithiolene monoradical, while dimerization couples the latter radical units via a Ni2S2 rhomb. Magnetic data (SQUID) on the dimer dication found a singlet ground state with a thermally accessible triplet state that is responsible for magnetism. A theoretical model built on an H4 chain explains this unexpected ferromagnetic low-energy triplet state arising from the antiferromagnetic coupling of a four-radical molecular conglomerate. For comparison, two (NO)Fe(N2S2) were connected through diamagnetic group 10 cations producing diradical trimetallic complexes. Antiferromagnetic coupling is observed between {Fe(NO)}7 units, with exchange coupling constants (J) of -3, -23, and -124 cm-1 for NiII, PdII, and PtII, respectively. This trend is explained by the enhanced covalency and polarizability of sulfur-dense metallodithiolate ligands. A central paramagnetic trans-Cr(NO)(MeCN) receiver unit core results in a cissoid structural topology, influenced by the stereoactivity of the lone pair(s) on the sulfur donors. This {Cr(NO)}5 radical bridge, unlike all previous cases, finds the coupling between the distal Fe(NO) radicals to be ferromagnetic (J = 24 cm-1).The stability and predictability of this S = 1/2 moiety and the steric/electronic properties of the bridging thiolate sulfurs suggest it to be a likely candidate for the development of novel molecular (magnetic) compounds and possibly materials. The role of synthetic inorganic chemistry in designing synthons that permit connections of the (NO)Fe(N2S2) metalloligand is highlighted as well as the properties of the heterobi- and polymetallic complexes derived therefrom.
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Affiliation(s)
- Manuel Quiroz
- Department of Chemistry, Texas
A & M University, College Station, Texas 77843, United States
| | - Marcetta Y. Darensbourg
- Department of Chemistry, Texas
A & M University, College Station, Texas 77843, United States
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3
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Wu C, Kakarla LN, Chandrasekaran CP, Zhang X, Mague JT, Sproules S, Donahue JP. Asymmetric by Design: Heteroleptic Coordination Compounds with Redox-Active Dithiolene and 1,2,4,5-Tetrakis(isopropylthio)benzene Ligands. Inorg Chem 2024; 63:173-183. [PMID: 38134365 PMCID: PMC10777400 DOI: 10.1021/acs.inorgchem.3c02928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/22/2023] [Accepted: 11/24/2023] [Indexed: 12/24/2023]
Abstract
The 1,2,4,5-tetrakis(alkylthio)benzenes are redox-active organosulfur molecules that support oxidation to a stable radical cation. Their utility as ligands for the assembly of multimetal complexes with tailored functionality/property is unexamined. Here, 1,2,4,5-tetrakis(isopropylthio)benzene (tptbz, 1) is shown to bind PdCl2 at either one end, leaving the other open, or at both ends to form centrosymmetric [Cl2Pd(tptbz)PdCl2], 4. Ligand metathesis between Na2[(N≡C)2C2S2] (Na2mnt) and [Cl2M(tptbz)] (M = Pd, 2; M = Pt, 3) yields [(mnt)M(tptbz)] (M = Pd, 5; M = Pt, 6), but an alternative route involving transmetalation with [(mnt)SnMe2] delivers substantially greater yield. The mixed dithiolene-dithioether compound [(Ph2C2S2)Pt(tptbz)] (8) is formed by a similar transmetalation protocol using [(Ph2C2S2)SnnBu2]. Compounds 5, 6, and 8 are the first such heteroleptic complexes prepared by deliberate synthesis. The cyclic voltammetry of 8 reveals anodic waves at +0.14 and +0.97 V vs Fc+/Fc, which are attributed to successive dithiolene oxidation processes. While oxidized at +0.73 V as a free ligand, the redox-active MO of tptbz is pushed to a higher potential upon coordination to Pt2+ and is inaccessible. Calculations of the structures of [8]+ and of [((Cl2-3,5-C6H3)2C2S2)Pt(tptbz)]+ show that, in the latter, the dithiolene MOs are drawn down in energy into proximity with the tptbz MOs.
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Affiliation(s)
- Che Wu
- Department
of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118-5698, United States
| | - Lakshmi Nishanth Kakarla
- Department
of Chemistry and Biochemistry, Lamar University, Beaumont, Texas 77710, United States
| | | | - Xiaodong Zhang
- Department
of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118-5698, 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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4
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Kumar S, Selvachandran M, Wu C, Pascal RA, Zhang X, Grusenmeyer T, Schmehl RH, Sproules S, Mague JT, Donahue JP. Heterotrimetallic Assemblies with 1,2,4,5-Tetrakis(diphenylphosphino)benzene Bridges: Constructs for Controlling the Separation and Spatial Orientation of Redox-Active Metallodithiolene Groups. Inorg Chem 2022; 61:17804-17818. [DOI: 10.1021/acs.inorgchem.2c03112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Satyendra Kumar
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Malathy Selvachandran
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Che Wu
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Robert A. Pascal
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Xiaodong Zhang
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Tod Grusenmeyer
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Russell H. Schmehl
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Stephen Sproules
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Joel T. Mague
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - James P. Donahue
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
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5
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Schallenberg D, Pardemann N, Villinger A, Seidel WW. Synthesis and coordination behaviour of 1 H-1,2,3-triazole-4,5-dithiolates. Dalton Trans 2022; 51:13681-13691. [PMID: 36000523 DOI: 10.1039/d2dt00410k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The preparative access to and first group 10 metal complexes of novel 1H-1,2,3-triazole-4,5-dithiolate ligands (tazdt2-) are reported. A set of S-protected 1H-1,2,3-triazole-4,5-dithiol derivatives with R1 = 2,6-dimethylphenyl (Xy) or benzyl (Bn) at N1 and with R2 = Bn or trimethylsilylethyl (TMS-ethyl) at both S atoms were synthesized by a 1,3-dipolar cycloaddition catalysed by either Ru(II) or Cu(I). Extensive investigations on the removal of the protective groups resulted the reductive removal of benzyl groups to be superior in isolating the free 4,5-dithiols of R1N3C2(SH)2 with R1 = Xy (H2-8) or Bn (H2-9). Coordination of these ligands led to the formation of the metal complexes [(η5-C5H5)2Ti(8)], [Ni(dppe)(8)], [Ni(dppe)(9)], [Pd(dppe)(9)] {dppe = bis(diphenylphosphanyl)ethane} and homoleptic (NBu4)n[Ni(8)2] (n = 1, 2). All complexes were fully characterized including structure determination by single crystal XRD. The electronic properties of the Ni and Pd complexes were determined by cyclic voltammetry, UV/vis and EPR spectroscopy supported by DFT calculations. According to the spectral and electrochemical data, the tazdt2- complexes resemble the corresponding benzene-1,2-dithiolate (bdt2-) type compounds reflecting the restricted influence of the electron-withdrawing N3 moiety in the backbone. DSC-TGA measurements with [(η5-C5H5)2Ti(8)] and [Ni(dppe)(8)] indicate a well-defined thermal process involving simultaneous elimination of both N2 and CS.
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Affiliation(s)
- David Schallenberg
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059 Rostock, Germany.
| | - Nils Pardemann
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059 Rostock, Germany.
| | - Alexander Villinger
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059 Rostock, Germany.
| | - Wolfram W Seidel
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059 Rostock, Germany. .,Leibniz Institut für Katalyse e.V., Albert-Einstein-Straße 29a, 18059 Rostock, Germany
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6
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Quiroz M, Lockart MM, Saber MR, Vali SW, Elrod LC, Pierce BS, Hall MB, Darensbourg MY. Cooperative redox and spin activity from three redox congeners of sulfur-bridged iron nitrosyl and nickel dithiolene complexes. Proc Natl Acad Sci U S A 2022; 119:e2201240119. [PMID: 35696567 PMCID: PMC9233302 DOI: 10.1073/pnas.2201240119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 05/06/2022] [Indexed: 12/15/2022] Open
Abstract
The synthesis of sulfur-bridged Fe-Ni heterobimetallics was inspired by Nature's strategies to "trick" abundant first row transition metals into enabling 2-electron processes: redox-active ligands (including pendant iron-sulfur clusters) and proximal metals. Our design to have redox-active ligands on each metal, NO on iron and dithiolene on nickel, resulted in the observation of unexpectedly intricate physical properties. The metallodithiolate, (NO)Fe(N2S2), reacts with a labile ligand derivative of [NiII(S2C2Ph2)]0, NiDT, yielding the expected S-bridged neutral adduct, FeNi, containing a doublet {Fe(NO)}7. Good reversibility of two redox events of FeNi led to isolation of reduced and oxidized congeners. Characterization by various spectroscopies and single-crystal X-ray diffraction concluded that reduction of the FeNi parent yielded [FeNi]-, a rare example of a high-spin {Fe(NO)}8, described as linear FeII(NO-). Mössbauer data is diagnostic for the redox change at the {Fe(NO)}7/8 site. Oxidation of FeNi generated the 2[FeNi]+⇌[Fe2Ni2]2+ equilibrium in solution; crystallization yields only the [Fe2Ni2]2+ dimer, isolated as PF6- and BArF- salts. The monomer is a spin-coupled diradical between {Fe(NO)}7 and NiDT+, while dimerization couples the two NiDT+ via a Ni2S2 rhomb. Magnetic susceptibility studies on the dimer found a singlet ground state with a thermally accessible triplet excited state responsible for the magnetism at 300 K (χMT = 0.67 emu·K·mol-1, µeff = 2.31 µB), and detectable by parallel-mode EPR spectroscopy at 20 to 50 K. A theoretical model built on an H4 chain explains this unexpected low energy triplet state arising from a combination of anti- and ferromagnetic coupling of a four-radical molecular conglomerate.
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Affiliation(s)
- Manuel Quiroz
- Department of Chemistry, Texas A&M University, College Station, TX 77843
| | - Molly M. Lockart
- Department of Chemistry & Biochemistry, Samford University, Birmingham, AL 35229
| | - Mohamed R. Saber
- Chemistry Department, Faculty of Science, Fayoum University, Fayoum 63514, Egypt
| | - Shaik Waseem Vali
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77845
| | - Lindy C. Elrod
- Department of Chemistry, Texas A&M University, College Station, TX 77843
| | - Brad S. Pierce
- Department of Chemistry & Biochemistry, University of Alabama, Tuscaloosa, AL 35487
| | - Michael B. Hall
- Department of Chemistry, Texas A&M University, College Station, TX 77843
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7
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Zuckerman LA, Vargo NP, May CV, Crockett MP, Hyre AS, McNeely J, Elinburg JK, Brown AM, Robinson JR, Rheingold AL, Doerrer LH. Thiolate-Thione Redox-Active Ligand with a Six-Membered Chelate Ring via Template Condensation and Its Pt(II) Complexes. Inorg Chem 2021; 60:13376-13387. [PMID: 34382778 DOI: 10.1021/acs.inorgchem.1c01693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new template condensation reaction has been discovered in a mixture of Pt(II), thiobenzamide, and base. Four complexes of the general form [Pt(ctaPhR)2], R = CH3 (1a), H (1b), F (1c), Cl (1d), cta = condensed thioamide, have been prepared under similar conditions and thoroughly characterized by 1H NMR and UV-vis-NIR spectroscopy, (spectro)electrochemistry, elemental analysis, and single-crystal X-ray diffraction. The ligand is redox active and can be reduced from the initial monoanion to a dianionic and then trianionic state. Chemical reduction of 1a with [Cp2Co] yielded [Cp2Co]2[Pt(ctaPhCH3)2], [Cp2Co]2[1a], which has been similarly characterized with the addition of EPR spectroscopy and SQUID magnetization. The singly reduced form containing [1a]1-, (nBu4N)[Pt(ctaPhCH3)2], has been generated in situ and characterized by UV-vis and EPR spectroscopies. DFT studies of 1b, [1b]1-, and [1b]2- confirm the location of additional electrons in exclusively ligand-based orbitals. A detailed analysis of this redox-active ligand, with emphasis on the characteristics that favor noninnocent behavior in six-membered chelate rings, is included.
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Affiliation(s)
- Linda A Zuckerman
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Natasha P Vargo
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Claire V May
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Michael P Crockett
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Ariel S Hyre
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - James McNeely
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Jessica K Elinburg
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Alexander M Brown
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Jerome R Robinson
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Arnold L Rheingold
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0332, La Jolla, California 92093, United States
| | - Linda H Doerrer
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
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8
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Abstract
AbstractNickel-catalyzed cross-coupling and photoredox catalytic reactions has found widespread utilities in organic synthesis. Redox processes are key intermediate steps in many catalytic cycles. As a result, it is pertinent to measure and document the redox potentials of various nickel species as precatalysts, catalysts, and intermediates. The redox potentials of a transition-metal complex are governed by its oxidation state, ligand, and the solvent environment. This article tabulates experimentally measured redox potentials of nickel complexes supported on common ligands under various conditions. This review article serves as a versatile tool to help synthetic organic and organometallic chemists evaluate the feasibility and kinetics of redox events occurring at the nickel center, when designing catalytic reactions and preparing nickel complexes.1 Introduction1.1 Scope1.2 Measurement of Formal Redox Potentials1.3 Redox Potentials in Nonaqueous Solution2 Redox Potentials of Nickel Complexes2.1 Redox Potentials of (Phosphine)Ni Complexes2.2 Redox Potentials of (Nitrogen)Ni Complexes2.3 Redox Potentials of (NHC)Ni Complexes
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9
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Kumar S, Selvachandran M, Arumugam K, Shaw MC, Wu C, Maurer M, Zhang X, Sproules S, Mague JT, Donahue JP. Open-Ended Metallodithiolene Complexes with the 1,2,4,5-Tetrakis(diphenylphosphino)benzene Ligand: Modular Building Elements for the Synthesis of Multimetal Complexes. Inorg Chem 2021; 60:13177-13192. [PMID: 34370468 PMCID: PMC8424627 DOI: 10.1021/acs.inorgchem.1c01573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Open-ended, singly
metalated dithiolene complexes with 1,2,4,5-tetrakis(diphenylphosphino)benzene
(tpbz) are prepared either by ligand transfer to [Cl2M(tpbz)]
from (R2C2S2)SnR′2 (R = CN, R′ = Me; R = Me, R′ = nBu) or by a direct reaction between tpbz and [M(S2C2R2)2] (M = Ni, Pd, Pt; R = Ph, p-anisyl) in a 1:1 ratio. The formation of dimetallic [(R2C2S2)M(tpbz)M(S2C2R2)] attends these syntheses in modest amounts, but the
open-ended compounds are readily separated by silica chromatography.
As affirmed by X-ray crystallographic characterization of numerous
members of the set, the [(R2C2S2)M(tpbz)]
compounds show dithiolene ligands in their fully reduced ene-1,2-dithiolate
form conjoined with divalent Group 10 ions. Minor amounts of octahedral
[(Ph2C2S2)2PtIV(tpbz)], a presumed intermediate, are isolated from the preparation
of [(Ph2C2S2)PtII(tpbz)].
Heterodimetallic [(Ph2C2S2)Pt(tpbz)Ni(S2C2Me2)] is prepared from [(Ph2C2S2)PtII(tpbz)]; its cyclic voltammogram,
upon anodic scanning, shows two pairs of closely spaced, but resolved,
1e– oxidations corresponding first to [R2C2S22–] –
1e– → [R2C2S•S–] and then to [R2C2S•S–] – 1e– → [R2(C=S)2]. The open diphosphine
of [(R2C2S2)M(tpbz)] can be oxidized
to afford open-ended [(R2C2S2)M(tpbzE2)] (E = O, S). Synthesis of the octahedral [(dppbO2)3Ni][I3]2 [dppbO2 =
1,2-bis(diphenylphosphoryl)benzene] suggests that the steric profile
of [(R2C2S2)M(tpbzE2)]
is moderated enough that three could be accommodated as ligands around
a metal ion. Open-ended metallodithiolene complexes
with 1,2,4,5-tetrakis(diphenylphosphino)benzene
(tpbz) are prepared either by the reaction of [M(S2C2R2)2] with tpbz in a 1:1 ratio or by
transmetalation from [(R2C2S2)SnR′2] to [Cl2M(tpbz)]. 31P NMR spectroscopy
provides a clear diagnostic with the metalated (∼55 ppm) and
open-phosphine (−14 ppm) signals. These compounds may be metalated
at their open end to produce heterodimetallic compounds, or the open
phosphines may be oxidized with chalcogen donors to the corresponding
phosphine oxides or sulfides.
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Affiliation(s)
- Satyendra Kumar
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Malathy Selvachandran
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Kuppuswamy Arumugam
- Department of Chemistry, Wright State University, 3640 Colonel Glenn Highway, Dayton, Ohio 45435-0001, United States
| | - Mohamed C Shaw
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Che Wu
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Michael Maurer
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Xiaodong Zhang
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - Stephen Sproules
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Joel T Mague
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
| | - James P Donahue
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, United States
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10
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Selvachandran M, Kumar S, Zhang X, Mague JT, Donahue JP. Tetrakis-1,2,4,5-(bis(3,5-dimethylphenyl)phosphino)benzene (Me16tpbz): A soluble and spectroscopically simple variant of the 1,2,4,5-tetraphosphinobenzene ligand platform. Polyhedron 2021. [DOI: 10.1016/j.poly.2020.114985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Selvakumar J, Simpson SM, Zurek E, Arumugam K. An electrochemically controlled release of NHCs using iron bis(dithiolene) N-heterocyclic carbene complexes. Inorg Chem Front 2021. [DOI: 10.1039/d0qi00638f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A series of five coordinated [Fe(NHC)(S2C2R2)2] complexes were isolated and subjected to electrochemical reduction for the facile release of NHCs in the catalytic media.
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Affiliation(s)
| | - Scott M. Simpson
- Department of Chemistry
- St. Bonaventure University
- St. Bonaventure
- USA
| | - Eva Zurek
- Department of Chemistry
- State University of New York at Buffalo
- Buffalo
- USA
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12
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Obanda A, Valerius K, Mague JT, Sproules S, Donahue JP. Group 10 Metal Dithiolene Bis(isonitrile) Complexes: Synthesis, Structures, Properties, and Reactivity. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00375] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Antony Obanda
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118-5698, United States
| | - Kendra Valerius
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118-5698, 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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Vacher A, Le Gal Y, Roisnel T, Dorcet V, Devic T, Barrière F, Lorcy D. Electronic Communication within Flexible Bisdithiolene Ligands Bridging Molybdenum Centers. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00485] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Antoine Vacher
- Université de Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Yann Le Gal
- Université de Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Thierry Roisnel
- Université de Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Vincent Dorcet
- Université de Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Thomas Devic
- Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, UMR CNRS 6502, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France
| | - Frédéric Barrière
- Université de Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Dominique Lorcy
- Université de Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
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McGuire J, Miras HN, Richards E, Sproules S. Enabling single qubit addressability in a molecular semiconductor comprising gold-supported organic radicals. Chem Sci 2019; 10:1483-1491. [PMID: 30809365 PMCID: PMC6354843 DOI: 10.1039/c8sc04500c] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/21/2018] [Indexed: 01/24/2023] Open
Abstract
A bis(dithiolene)gold complex is presented as a model for an organic molecular electron spin qubit attached to a metallic surface that acts as a conduit to electrically address the qubit. A two-membered electron transfer series is developed of the formula [AuIII(adt)2]1-/0, where adt is a redox-active dithiolene ligand that is sequentially oxidized as the series is traversed while the central metal ion remains AuIII and steadfastly square planar. One-electron oxidation of diamagnetic [AuIII(adt)2]1- (1) produces an S = 1/2 charge-neutral complex, [AuIII(adt2 3-˙)] (2) which is spectroscopically and theoretically characterized with a near negligible Au contribution to the ground state. A phase memory time (T M) of 21 μs is recorded in 4 : 1 CS2/CCl4 at 10 K, which is the longest ever reported for a coordination complex possessing a third-row transition metal ion. With increasing temperature, T M dramatically decreases becoming unmeasurable above 80 K as a consequence of the diminishing spin-lattice (T 1) relaxation time fueled by spin-orbit coupling. These relaxation times are 1-2 orders of magnitude shorter for the solid dilution of 2 in isoelectronic [Ni(adt)2] because this material is a molecular semiconductor. Although the conducting properties of this material provide efficient pathways to dissipate the energy through the lattice, it can also be used to electrically address the paramagnetic dopant by tapping into the mild reduction potential to switch magnetism "on" and "off" in the gold complex without compromising the integrity of its structure. These results serve to highlight the need to consider all components of these spintronic assemblies.
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Affiliation(s)
- Jake McGuire
- WestCHEM School of Chemistry , University of Glasgow , Glasgow , G12 8QQ , UK .
| | - Haralampos N Miras
- WestCHEM School of Chemistry , University of Glasgow , Glasgow , G12 8QQ , UK .
| | - Emma Richards
- School of Chemistry , Cardiff University , Main Building, Park Place , Cardiff , CF10 3AT , UK
| | - Stephen Sproules
- WestCHEM School of Chemistry , University of Glasgow , Glasgow , G12 8QQ , UK .
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McGuire J, Miras HN, Donahue JP, Richards E, Sproules S. Ligand Radicals as Modular Organic Electron Spin Qubits. Chemistry 2018; 24:17598-17605. [PMID: 30291646 DOI: 10.1002/chem.201804165] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Indexed: 01/08/2023]
Abstract
The intrinsic redox activity of the dithiolene ligand is presented here as the novel spin host in the design of a prototype molecular electron spin qubit, where the traditional roles of the metal and ligand components in coordination complexes are inverted. A series of paramagnetic bis(dithiolene) complexes with group 10 metals-nickel, palladium, platinum-provides a backdrop to investigate the spin dynamics of the organic ligand radical using pulsed EPR spectroscopy. The temperature dependence of the phase memory time (TM ) is shown to be dependent on the identity of the diamagnetic metal ion, with the short times recorded for platinum a consequence of a diminishing spin-lattice (T1 ) relaxation time driven by spin-orbit coupling. The utility of the radical ligand spin center is confirmed when it delivers one of the longest phase memory times ever recorded for a molecular two-qubit prototype.
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Affiliation(s)
- Jake McGuire
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Haralampos N Miras
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK
| | - James P Donahue
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans, Louisiana, 70118, USA
| | - Emma Richards
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Stephen Sproules
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK
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