Thiolate Dimers Research Articles

Rh nanoparticles from thiolate dimers: selective and reusable hydrogenation catalysts in ionic liquids

Thiolate-capped RhNPs in imidazolium-based ionic liquids were synthesized from [Rh(μ-SR)(COD)]2dimmers under H2pressure without external addition of ligand stabilizers, preserving thiolate integrity on the nanoparticle surface. This nanoparticulated systems showed a remarkable selectivity that led to their application in theone potreductiveN-alkylation to produce amines.

Synthesis and interconversions of reduced, alkali-metal supported iron-sulfur-carbonyl complexes.

We report the synthesis, interconversions and X-ray structures of a set of [mFe-nS]-type carbonyl clusters (where S = S2-, S22- or RS-; m = 2-3; n = 1-2). All of the clusters have been identified and characterized by single crystal X-ray diffraction, IR and 13C NMR. Reduction of the parent neutral dimer [μ2-(SPh)2Fe2(CO)6] (1) with KC8 affords an easily separable ∼1 : 1 mixture of the anionic, dimeric thiolate dimer K[Fe2(SPh)(CO)6(μ-CO)] (2) and the dianionic, sulfido trimer [K(benzo-15-crown-5)2]2[Fe3(μ3-S)(CO)9] (3). Oxidation of 2 with diphenyl-disulfide (Ph2S2) cleanly returns the starting material 1. The Ph-S bond in 1 can be cleaved to form sulfide trimer 3. Oxidation of sulfido trimer 3 with [Fc](PF6) in the presence of S8 cleanly affords the all-inorganic persulfide dimer [μ2-(S)2Fe2(CO)6] (4), a thermodynamically stable product. The inverse reactions to form 3 (dianion) from 4 (neutral) were not successful, and other products were obtained. For example, reduction of 4 with KC8 afforded the mixed valence Fe(i)/Fe(ii) species [((FeS2)(CO)6)2FeII]2- (5), in which the two {Fe2S2(CO)6}2- units serve as bidendate ligands to a Fe(ii) center. Another isolated product (THF insoluble portion) was recrystallized in MeCN to afford [K(benzo-15-crown-5)2]2[((Fe2S)(CO)6)2(μ-S)2] (6), in which a persulfide dianion bridges two {2Fe-S} moieties (dimer of dimers). Finally, to close the interconversion loop, we converted the persulfide dimer 4 into the thiolate dimer 1 by reduction with KC8 followed by reaction with the diphenyl iodonium salt [Ph2I](PF6), in modest yield. These reactions underscore the thermodynamic stability of the dimers 1 and 4, as well as the synthetic and crystallization versatility of using the crown/K+ counterion system for obtaining structural information on highly reduced iron-sulfur-carbonyl clusters.

Thiophene-containing thiolato dimers, oxygen inserted Cu(II) complex, crystal structures, molecular docking and theoretical studies

Reactions of n-butyl- and n-octyl-thiophene with CS2 at 0 °C resulted in thiolate dimers 1 and 2, respectively. The reaction of 1 with Cu(NO3)2·3H2O in methanol under ambient reaction conditions yielded monomeric [CuII{(n-C4H9(C4H2S)CS2O}2] (3). 1 and 3 were authenticated by their single-crystal X-ray crystal structures. Crystal structure of 3 revealed cleavage of the S-S bond of 1 followed by insertion of O-atom, forming a new five-membered Cu–O–S–C–S metallacycle. 1, 2, and 3 were further investigated for their bioactivity through molecular docking with nine different proteins having medicinal implications. Molecular docking of 1, 2 and 3 revealed considerable interaction with different proteins viz. cancer protein Tankyrase 2, influenza viral protein Polymerase subunit PAC–PB1N complex (H5N1), Polymerase subunit PA endonuclease (H1N1), Polymerase subunit PAn Apo(avian influenza), and FTSZ (Bacillus subtilis). Comparatively, 1 has promising application in therapeutics as compared to 2 and 3 based on its inhibitory constant and binding energy. Density functional theory calculations were performed to better understand the bonding of complex using MO diagram in 1–3. Moreover, TDDFT calculations were performed to facilitate the assignment of electronic transitions of UV–Vis spectra.

In Situ Video-STM Studies of Methyl Thiolate Surface Dynamics and Self-Assembly on Cu(100) Electrodes

The atomic-scale surface dynamic behavior of adsorbed methyl thiolate on Cu(100) electrodes, prepared via the dissociative adsorption of dimethyl disulfide, was studied in 0.01 M HCl solution over a wide regime of coverages. Using video-rate in situ STM, we directly observed the motion of the adsorbates within the c(2 × 2) lattice of the chloride coadsorbates with high spatial and temporal resolution, revealing complex mutual interactions of the organic adsorbates as well as pronounced interactions with Cu adatoms, which significantly affect the thiolate self-assembly. Quantitative measurements of the tracer diffusion of isolated thiolates reveal a 35 meV lower diffusion barrier as compared to that of sulfide adsorbates with a linear potential dependence of 0.5 eV/V. The effective intermolecular interactions between the thiolates resemble those between adsorbed sulfide and are repulsive at the nearest-neighbor distance of a(0) within the c(2 × 2) lattice, attractive at the next-nearest-neighbor distance of √2a(0) and again repulsive at a distance of 2a(0). Thiolates at these small spacings are found to exhibit characteristic collective properties, which are significant for the self-assembly of these species: First, their mobility is greatly enhanced relative to that of isolated thiolates. Second, Cu adatoms can be transiently trapped in between the two thiolates of a metastable dimer with an intermolecular spacing of √2a(0). With increasing coverage, small, highly mobile molecular clusters and subsequently the formation of ordered adlayer domains with a c(2 × 6) structure are observed. Common structural elements of the clusters and c(2 × 6) domains are stripes of thiolate dimers, which are oriented in the [011] direction, spaced at distances of √2a(0) and of which a large fraction is occupied by Cu adatoms. The c(2 × 6) phase can be rationalized as a close-packed arrangement of these dimer stripes. Because of the self-acceleration of the thiolate mobility, the ordering and reorganization of the ordered c(2 × 6) adlayers occur orders of magnitude faster than the surface diffusion of isolated thiolates, illustrating the importance of collective effects in organic self-organization.

Reactivity of a Sterically Hindered Fe(II) Thiolate Dimer with Amines and Hydrazines

The sterically hindered Fe(II) thiolate dimer Fe(2)(mu-STriph)(2)(STriph)(2) (1; [STriph](-) = 2,4,6-triphenylbenzenethiolate) reacts with primary amines ((t)BuNH(2), aniline) and N(2)H(4) to form the structurally characterized addition complexes Fe(STriph)(2)(NH(2)(t)Bu)(2), Fe(2)(mu-STriph)(2)(STriph)(2)(NH(2)Ph)(2), and Fe(2)(mu-eta(1):eta(1)-N(2)H(4))(2)(N(2)H(4))(4)(STriph)(4) in high yield. Chemical and NMR spectroscopic evidence indicate that the binding of these nitrogen donors is labile in solution and multispecies equilibria are likely. With arylhydrazines, 1 catalytically disproportionates 1,2-diphenylhydrazine to aniline and azobenzene, and it rearranges 1-methyl-1,2-diarylhydrazines to give, after treatment with alumina, mononuclear, trigonal bipyramidal Fe(III) complexes of composition Fe(ISQ)(2)(STriph), where [ISQ](-) denotes an appropriately substituted bidentate o-diiminobenzosemiquinonate ligand. Complex 1 shows no reaction with hindered 1,2-dialkylhydrazines (isopropyl or tert-butyl) or tetrasubstituted 1,2-dimethyl-1,2-diphenylhydrazine.

Coexistence of the (23 × √3) Au(111) Reconstruction and a Striped Phase Self-Assembled Monolayer

We have studied the effect of adsorption of a low-density alkanethiol monolayer on the state of the Au(111) reconstruction. It is commonly believed that the substrate deconstructs following formation of a thiolate self-assembled monolayer, but our results suggest this is not always the case. Helium diffraction from 1-decanethiol and 1-octanethiol striped phase monolayers is exploited to establish the surface nearest-neighbor spacing and to illustrate a unit cell corresponding to the long dimension of the (23 × √3) reconstruction. Using our observed 0.198 A-1 peak spacing and the (11.5 × √3) unit cell reported in the literature, we measure a substrate nearest-neighbor spacing of 2.76 A along the [110] direction, which represents the atomic spacing of the uniaxially compressed, reconstructed gold surface. Moreover, 1/2-order peaks in the diffraction from decanethiol/Au(111) demonstrate a distinction between neighboring thiolate dimers. These peaks are not observed for the octanethiol/Au(111) system. Theref...

DFT analysis of the activation and breaking of the Mo-N bond in a (mu-nitrido)dimolybdenum complex: is molybdenum tris(thiolate) an elusive intermediate?

The electronic structure, conformation, synthesis, and thermal decomposition pathways of the recently characterized dimolybdenum mu-nitrido complex (AdS)(3)Mo(mu-N)Mo(N[(t)Bu]Ph)(3) (1exp, Ad = adamantyl) are investigated by means of DFT calculations carried out on the model system (HS)(3)Mo(mu-N)Mo(NH(2))(3) (1). The observed asymmetry of the Mo(mu-N)Mo core is reproduced in the optimal conformation of 1 and assigned to the tendency for the electron density of the metal atoms to be preferably accommodated in the pi orbitals of Mo(thiolate). The balance in the metal-ligand and ligand-ligand interactions conditioning the flow of the electron density along the Mo-(mu-N)-Mo framework, and eventually the relative activation of the molybdenum-nitrido bonds, appears very sensitive to the nature of the ancillary substituents on both the thiolate and the amido sides. On one hand, replacing HS by AdS in 1 increases the calculated value of Delta(mu-N-Mo) from 0.053 to 0.094 A, close to the experimental value of 0.111 A. The mu-nitrido complex with bulky thiolates 1a is also less stable than 1 by 7.3 kcal x mol(-1) with respect to its monometallic constituents. On the other hand, substituting the bulky N[(t)Bu]Ph for NH(2) in the model complex 1b induces an important charge transfer toward the thiolate moiety resulting in structural and energetic consequences of similar magnitude. Even though these substitutional effects are not likely to be fully additive in the real complex, both should contribute to an increase of the mu-N-Mo(thiolate) bond activation in 1exp. The importance of this activation conditions the feasibility of the thermal decomposition of 1exp promoted by benzonitrile which eventually yields the molybdenum thiolate dimer (RS)(3)Mo [triple bond] Mo(SR)(3). The energy profile calculated for this reaction with model complex1 in the presence of one or two molecules of acetonitrile shows that the axial fixation of the promoter on one or both molecular ends forms intermediates in which the mu-N-Mo(thiolate) bond is further activated with respect to the original complex. The consequence is an important, but still insufficient, decrease of the barrier to Mo-N bond breaking, from 53 to 37 kcal x mol(-1). Furthermore, the thermodynamic balance of the reaction leading from the acetonitrile adducts of 1 to (HS)(3)Mo [triple bond] Mo(SH)(3) remains endothermic by 6.5 kcal x mol(-1) for the monoadduct, and more for the diadduct. It therefore appears that bulky substituents on both ends of the dinuclear complex are essential to the completion of the reaction, from both the thermodynamic and the kinetic viewpoints.

Formation of rhodium carbonyl thiolate dimers via elimination of dihydrogen; crystal and molecular structure of [Rh 2(CO) 4(μ-SC 6H 4CH 3) 2

Reaction of [Rh 6(CO) 15(NCMe)] with p-thiocresol [(4-Me)C 6H 4SH] leads to the formation of [Rh 2(CO) 4(μ-SC 6H 4CH 3) 2] as the main product along with a small amount of [Rh 6(CO) 16]. An approximately 30-fold excess of the thiol is required in order to obtain a good yield of the thiolate-bridged dimer while reaction of [Rh 4(CO) 12] with an excess of p-thiocresol leads to an apparently clean conversion to the dimeric Rh(I) complex. Mass spectrometric measurements show that the latter reaction involves evolution of H 2, and CO evolution is indicated by the retardation of the reaction in CO saturated solution; these results suggest the following reaction stoichiometry: [Rh 4(CO) 12]+4RSH→2[Rh 2(CO) 4(μ-SR) 2]+2H 2+4CO. Kinetic measurements show that the reaction proceeds in three stages which are proposed to involve two rapid pre-equilibria and a final irreversible and relatively slow conversion to the products. The crystal and molecular structure of [Rh 2(CO) 4(μ 2-SC 6H 4CH 3) 2] is reported.

Synthesis and Structures of Gallium Alkylthiolate Compounds

Gallium alkylthiolate complexes have been prepared from gallium amide complexes and thiols. The amide complex [Ga(NMe2)3]2 reacts with excess t-BuSH to give the amine adduct Ga(S-t-Bu)3(HNMe2). In contrast, the bulky amide complex Ga(N-i-Pr2)3 reacts with t-BuSH to give the homoleptic thiolate dimer [Ga(S-t-Bu)3]2. The analogous reaction between Ga(N-i-Pr2)3 and i-PrSH produces the salt [i-Pr2NH2][Ga(S-i-Pr)4], which on heating under vacuum loses amine and thiol to give the dimer [Ga(S-i-Pr)3]2. Reactions of [i-Pr2NH2][Ga(S-i-Pr)4] and [Ga(S-t-Bu)3]2 with excess pyridine give the adducts Ga(SR)3(py) (R = i-Pr or t-Bu). X-ray crystallographic studies show that the dimers have two bridging thiolate ligands. The Ga(μ-SR)2Ga four-membered ring in [Ga(S-i-Pr)3]2 has a planar anti geometry while the ring in [Ga(S-t-Bu)3]2 has a butterfly syn configuration. In the solid state, Ga(S-t-Bu)3(HNMe2) and [i-Pr2NH2][Ga(S-i-Pr)4] have trigonal-pyramidal and distorted tetrahedral geometries, respectively. The [Ga(SR)3]2...

Synthesis and Characterization of Molecular Rectangles Based upon Rhenium Thiolate Dimers.

Tetrametallic molecular rectangles have been synthesized by combining rhenium(I) thiolate dimers with difunctional pyridyl and pyrazyl type ligands. The proposed rectangular structures are supported by 1H NMR, MS, and IR absorption measurements. In addition, crystal structures of two of the rectangles are presented showing frameworks with dimensions 3.81 × 11.57 and 3.69 × 7.22 A, as defined by the rhenium atoms.

Spectroscopy of Mixed-Valence CuA-Type Centers: Ligand-Field Control of Ground-State Properties Related to Electron Transfer

Using a combination of electronic spectroscopies, electronic structural descriptions have been developed for a series of binuclear CuA-type centers in Bacillus subtilis CcO and engineered into the blue copper proteins Pseudomonas aeruginosa azurin and Thiobacillus versutus amicyanin. Parallel descriptions are developed for two structurally characterized mixed-valence (MV) and homovalent (II,II) synthetic copper thiolate dimers. Assignment of the excited-state spectral features allows the electronic structures of CuA and the MV model to be understood and compared in relation to their copper coordination environments. These electronic structural descriptions are supported by SCF-Xα-SW MO calculations, which are used to test systematically the effects of major structural perturbations linking the MV model geometry to that of CuA. It is determined that both Cu−Cu compression and removal of the axial ligands are critical determinants of the orbital ground state in these dimers. The weakened axial interactions in CuA appear to parallel the mechanism for protein control of electron transfer (ET) function observed in blue copper centers. The major geometric and electronic features of CuA, including metal−ligand covalency, redox potentials, reorganization energies, valence delocalization, and the weakened axial bonding interactions, are discussed in relation to its ET function, and specific potential ET pathways are identified and compared.

Synthesis, structure, and characterization of a mixed-valence [nickel(II)nickel(III)] thiolate dimer

Synthesis, structure, and characterization of a mixed-valence [nickel(II)nickel(III)] thiolate dimer

Inorganic derivatives of iron sulfide thiolate dimers and tetramers: synthesis and properties of the halide series [Fe2S2X4]2- and [Fe4S4X4]2- (X = chlorine, bromine, iodine)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInorganic derivatives of iron sulfide thiolate dimers and tetramers: synthesis and properties of the halide series [Fe2S2X4]2- and [Fe4S4X4]2- (X = chlorine, bromine, iodine)Geoffrey B. Wong, M. A. Bobrik, and R. H. HolmCite this: Inorg. Chem. 1978, 17, 3, 578–584Publication Date (Print):March 1, 1978Publication History Published online1 May 2002Published inissue 1 March 1978https://doi.org/10.1021/ic50181a012RIGHTS & PERMISSIONSArticle Views1439Altmetric-Citations96LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (962 KB) Get e-Alerts Get e-Alerts