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The emerging promise of few-atom metal catalysts has driven the need for developing metal nanoclusters (NCs) with ultrasmall core size. However, the preparation of metal NCs with single-digit metallic atoms and atomic precision is a major challenge for materials chemists, particularly for Ag, where the structure of such NCs remains unknown. In this study, we developed a shape-controlled synthesis strategy based on an isomeric dithiol ligand to yield the smallest crystallized Ag NC to date: [Ag9(1,2-BDT)6]3– (1,2-BDT = 1,2-benzenedithiolate). The NC’s crystal structure reveals the self-assembly of two Ag square pyramids through preferential pyramidal vertex sharing of a single metallic Ag atom, while all other Ag atoms are incorporated in a motif with thiolate ligands, resulting in an elongated body-centered Ag9 skeleton. Steric hindrance and arrangement of the dithiolated ligands on the surface favor the formation of an anisotropic shape. Time-dependent density functional theory based calculations reproduce the experimental optical absorption features and identify the molecular orbitals responsible for the electronic transitions. Our findings will open new avenues for the design of novel single-digit metal NCs with directional self-assembled building blocks., An isomeric dithiol-based synthesis strategy is used to synthesize the smallest crystallized Ag nanocluster, [Ag9(1,2-BDT)6]3−. The single-digit cluster reveals novel bonding modes and building blocks, which include the self-assembly of two Ag square pyramids sharing a common vertex and six bidentate thiolate motifs.

A promising strategy for new electrically conductive coordination polymers is the combination of d10 metal ions, which tolerate short metal···metal distances, with dithiolene linkers, known for their "non-innocent" redox behavior. This study explores the coordination chemistry of 2,3-pyrazinedithiol (H2pdt) toward Cu+ and Ag+ ions, highlighting similarities and differences. The synthetic approach, starting with the fully protonated ligand, allowed the isolation of a homoleptic bis(dithiolene) complex with formal CuI atoms, [Cu(H2pdt)2]Cl (1). This complex was further transformed to a 1D coordination polymer with short metal···metal distances, 1D[Cu(Hpdt)] (2Cu). The larger Ag+ ion directly built up a very similar coordination polymer, 1D[Ag(Hpdt)] (2Ag), without any appearance of an intermediate metal complex. The coordination polymer 1D[Cu(H2pdt)I] (4), like complex 1, bears fully protonated H2pdt ligands in their dithione form. Upon heating, both compounds underwent auto-oxidation coupled with a dehydrogenation of the ligand to form the open-shell neutral copper(II) complex [Cu(Hpdt)2] (3) and the coordination polymer 1D[Cu2I2(H2pdt)(Hpdt)] (5), respectively. For all presented compounds, crystal structures are discussed in-depth. Furthermore, properties of 1, 3, and those of the three 1D coordination polymers, 2Ag, 2Cu, and 4, were investigated by UV-vis-NIR spectroscopy, cyclic voltammetry, and variable-temperature magnetic susceptibility, and direct current (dc)-conductivity measurements. The experimental results are compared and discussed with the aid of DFT simulations.

British anti-Lewisite (2,3-dimerkaptopropan-1-ol, dimercaprol, BAL) is one of the best-known chelator-type therapeutic agents against toxic metal ions and metalloids, especially arsenicals. Surprisingly, the mechanisms of action at the molecular level, as well as the coordination features of this traditional drug toward various arsenicals, are still poorly revealed. The present study on the interaction of arsenous acid (H

Arsenic-72 ((72)As) and (77)As have nuclear properties useful for positron emission tomography (PET) and radiotherapy, respectively. The thiophilic nature of arsenic led to the evaluation of dithioarylarsines for potential use in radiopharmaceuticals. Several dithioarylarsines were synthesized from their arylarsonic acids and dithiols and were fully characterized by NMR, ESI-MS, and X-ray crystallography. This chemistry was translated to the no-carrier-added (nca) (77)As level. Because arsenic was available at the nca nanomolar level only as [(77)As]arsenate, this required addition of an aryl group directly to the As to form the [(77)As]arylarsonic acid. The [(77)As]arsenate was reduced from (77)As (V) to (77)As (III), and a modified Bart reaction was used to incorporate the aryl ring onto the (77)As, which was followed by dithiol addition. Various modifications and optimizations resulted in 95% radiochemical yield of nca [(77)As]p-ethoxyphenyl-1,2-ethanedithiolatoarsine.

Four linear-type tetranuclear complexes, [Mn(5-Rsaltmen){M(dmit)2}]2 (R ) MeO, M ) Ni, 1a; M ) Au, 1b; R ) Me, M ) Ni, 2a; M ) Au, 2b), were synthesized and structurally characterized (5-Rsaltmen2- ) N,N ′-(1,1,2,2- tetramethylethylene)-bis(5-Rsalicylideneiminate), dmit2- ) 1,3-dithiol-2-thione-4,5-dithiolate). These compounds crystallize in the same triclinic P¯1 space group (Z ) 1) and have a similar molecular structure with a bridging array of [M-(dmit)-Mn-(OPh)2-Mn-(dmit)-M] and a packing feature where the respective sets of 1a/1b and 2a/2b are isomorphous. Intermolecular π-π/S * * * S contacts are observed between the coordinating [M(dmit)2]- moieties to form zigzag stair-like columns along the a axis direction. Hu¨ckel calculations revealed a strong intermolecular dimerization within the [Ni(dmit)2]- column that makes them magnetically silent even at room temperature. Nevertheless, 1a and 2a with M ) Ni behave as semiconductors with σr.t. ) 7 × 10-4 S * cm-1 and Ea ) 182 meV for 1a and σr.t. ) 1 × 10-4 S * cm-1 and Ea ) 292 meV for 2a, while 1b and 2b with M ) Au are insulators. As a result of the strong dimerization of the [Ni(dmit)2]- anions, the magnetic properties of 1a are essentially identical to those of 1b and 2b, which can be described as isolated Mn(III) dimers, acting as single-molecule magnets (SMM). Meanwhile, the magnetic properties of 2a are dominated by the intermolecular Mn * * * Mn antiferromagnetic interactions via the singlet [Ni(dmit)2]2 2- dimer (JMn * * * Mn/kB ) -2.85 K), inducing a long-range antiferromagnetic order at TN ) 6.4 K. The present systems are unique materials made of neutral single-component complexes that exhibit two major solid-state properties, that is, electrical conductivity and magnetism, varied as semiconductor/SMM for 1a, insulator/SMM for 1b and 2b, and semiconductor/antiferromagnet for 2a by tuning metal center and partial structural modification.

The synthesis and structures of two types of molecules are presented: [MVIO3 - nSn(OSiR2R')]1- (M = Mo, n = 0-3; M = W, n = 3) and [MVIO2(OSiR2R')(bdt)]1- (M = Mo, W; bdt = benzene-1,2-dithiolate). For both types, R2R' are Me3, Pri3, Ph3, Me2But and Ph2But. The complete series of oxo/sulfido/silyloxo molybdenum complexes has been prepared. Complexes with n = 0 are readily prepared by the silylation of Ag2MoO4 and sustain mono- or disulfidation with Ph3SiSH to form a species with n = 1 and n = 2, respectively. Complexes with n = 3 are accessible by the silylation of [MOS3]2-. Structures of the representative series members [MoO3(OSiPh2But)]1-, [MoO2S(OSiPh3)]1-, [MoOS2(OSiPri3)]1-, [MoS3(OSiPh2But)]1-, and also [WS3(OSiMe2But)]1-, all with tetrahedral stereochemistry, are presented. Benzene-1,2-dithiolate complexes are prepared by the reaction of [MoO3(OSiR2R')]1-with the dithiol or by the silylation of previously reported [MO3(bdt)]2-. The structures of [MoO2(OSiPh2But)(bdt)]1- and [WO2(OSiPri3)(bdt)]1- conform to square-pyramidal stereochemistry with an oxo ligand in the apical position. The role of these complexes in the preparation of site analogues of the xanthine oxidoreductase enzyme family is noted. The sulfidation reactions reported here point to the utility of Ph3SiSH and Pri3SiSH as reagents for MoVI-based oxo-for-sulfido conversions.

An unresolved structural issue for [FeFe]-hydrogenases is the nature of the dithiol-bridging ligand in the diiron subcluster of the active site. The two most probable candidates are 1,3-dithiopropane (propane dithiol, PDT) and di-(thiomethyl)-amine (DTN). In the latter case, the dithiol-bridging ligand is assumed to play a major role in the reaction cycle. We report density-functional theory studies of the differing roles of these dithiol-bridging ligands in the infrared spectra of synthetic models and of computational representations of the diiron cluster of the active site. Our analysis shows distinct spectral features associated with the dithiol-bridging NH mode for compounds having a DTN bridge, which, however, would have been obscured by the H 2 O vibrations in existing measurements. However, if indeed nitrogen is present in the dithiol-bridging ligand, a combination of selective deuteration and chemical inactivation with CO would create a unique signature in an accessible region of the infrared spectrum, whose position and intensity are predicted.

Phenylene-1,3-dithiol is converted into a trinuclear gold complex by treatment with 1 equiv of [[(Ph(3)P)Au](3)O](+)BF(4)(-). In the product, the phenylene unit bears one gold thiolate and one di(gold)sulfonium function. These components aggregate into one-dimensional arrays through head-to-tail aurophilic contacts between the two functions. In the association process, the Au[bond]S[bond]Au angle of the sulfonium group is opened up to accommodate the incoming gold atom between its metal centers. A similar mode of aggregation is found for the triply aurated biphenylene-4,4'-dithiol obtained using the tri(gold)oxonium salt with tri(p-tolyl)phosphine ligands. Probably for steric reasons, in this oligomerization process, the gold(I) thiolate unit is attached side-on to the digold sulfonium unit with retention of the small Au[bond]S[bond]Au angle. Under similar reaction conditions, and with the same molar ratio of the components, phenylene-1,4-dithiol is converted into the bis-sulfonium salt: 1,4-[[(p-Tol)(3)PAu](2)S](2)C(6)H(4)(BF(4))(2), the dications of which also associate into chains. Along the chains, the phenylene spacers alternate with tetranuclear gold clusters which arise from intimate aggregation of pairs of gold atoms. Together with previous findings, the present results show that gold thiolate (-SAuL) and digold sulfonium functions [-S(AuL)(2)(+)] in proper orientation at an arene unit (alpha-omega) can be considered as "soldering" points which can be used for joining up the molecular units into one-dimensional arrays solely through metal-metal contacts, which appear to be operative even against Coulomb repulsion between cations. The reaction of biphenylene-4,4'-dithiol with 2 equiv of sodium methoxide and [tri(c-hexyl)phosphine]gold chloride gives only neutral digold dithiolate complex 4 which is not associated owing to the steric bulk of the tri(c-hexyl)phosphine ligands.

Combination of the dithiol N,N'-bis(2-mercaptoethyl)isophthalamide, abbreviated as BDTH2 and as 1, with excess H2SeO3 in aqueous acidic (pH ≈ 1) conditions resulted in precipitation of BDT(S-Se-S) (6), with a (77)Se NMR chemical shift of δ = 675 ppm, and oxidized BDT. When the reaction is conducted under basic conditions Se(IV) is reduced to red Se(0) and oxidized 1. No reaction takes place between 1 and selenate (Se(VI)) under acidic or basic conditions. Compound 6 is stable in air but decomposes to red Se(0) and the disulfide BDT(S-S) (9) with heating and in basic solutions. Mechanisms and energetics of the reactions leading to 6 in aqueous solution were unraveled by extensive calculations at the ωB97X-D/aug-cc-pVTZ-PP level of theory. NMR chemical shift calculations with the gauge-independent atomic orbital (GIAO) method for dimethyl sulfoxide as solvent confirm the generation of 6 (calculated δ value = 677 ppm). These results define the conditions and limitations of using 1 for the removal of selenite from wastewaters. Compound 6 is a rare example of a bidentate selenium dithiolate and provides insight into biological selenium toxicity.

{sup 99}Tc complexes of the formula, TcO[SC(CH{sub 3}){sub 2}CH{sub 2}]{sub 2}NCH{sub 2}CH{sub 2}R X (X = benzyl mercaptan) were prepared, purified and characterized structurally. The compounds were prepared by reaction of 1:1 mixtures of Tc(V)-gluconates and tris-chelating ligand. Purification was performed by flash column chromatography. Structural characterization was obtained through NMR spectroscopy and X-ray crystal diffraction. In all cases studied, the side chain is in the syn configuration.

The synthesis, characterization, and emission properties of a series of Pt(L{sub 2})(S-S) complexes are reported. The (L{sub 2}) ligands include 4,7-diphenyl-1,10-phenanthroline (Ph{sub 2}phen), 4,4{prime}-dimethyl-2,2{prime}-bipyridine (Me{sub 2}bpy), 1,5-cyclo-octadiene (COD), trimethyl phosphite (P(OMe){sub 3}), and the {alpha}-C-deprotonated form of 2-phenylpyridine (2-phpy). The (S-S) ligands include 1-(tert-butoxycarbonyl)-1-cyanoethylene-2,2-dithiolate (tbcda), 1-(diethoxyphosphinyl)-1-cyanoethylene-2,2-dithiolate (cpdt), cis-1,2-dicarbomethoxyethylene-1,2-dithiolate (met), and N,N-diethyldithio-carbamate (Et{sub 2}dtc). The complexes are readily synthesized by the addition of the dithiolate or thiolate ligand to Pt(L{sub 2})Cl{sub 2} except for Pt(P(OMe){sub 3}){sub 2}(met), which is prepared by the addition of 2 equiv of trimethyl phosphite to Pt(COD)(met).

The compounds [CpTi(SCH 2 CH 2 S) 2 Na] n and [CpTi(SCH 2 CH 2 CH 2 S) 2 Na] n have been used as precursors to heterometallic compounds. Reaction with [Cu(NCMe) 4 ]BF 4 gives insoluble compounds formulated as [CpTi(SCH 2 -CH 2 S) 2 Cu] n (1) and [CpTi(SCH 2 CH 2 CH 2 S) 2 )Cu] 2 (2), respectively. Compound I is also formed in the reaction of [CpTi(SCH 2 CH 2 S)Cl] 2 with [Cu(NCMe) 4 ]BF 4 . The Rh(I) derivative [CpTi(SCH 2 CH 2 CH 2 S) 2 Rh] n (3) has been synthesized from the reaction of [CpTi(SCH 2 CH 2 CH 2 S) 2 Na] n and [(C 2 H 4 ) 2 RhCl] 2

Two monooxomolybdenum(IV) complexes with dithiolene-like benzenedithiolate ligands, (NEt 4 ) 2 [Mo IV O(Ph 3 Si-bdt) 2 ] (Ph 3 Si-bdt=3-(triphenylsilyl)-1,2-benzenedithiolato) and (NEt 4 ) 2 [Mo IV O(Ph 3 Si-tdt) 2 ] (Ph 3 Si-tdt=5-(triphenylsilyl)-3,4-toluenedithiolato), were synthesized as models of reduced state molybdenum oxidoreductase. The MoOS 4 cores of 1 and (NEt 4 ) 2 [Mo IV O(tdt) 2 ] (tdt=3,4-toluenedithiolato) have a square pyramidal geometry similar to that of (NEt 4 ) 2 [Mo IV O(bdt) 2 ] (bdt=1,2-benzenedithiolato)

The synthesis, characterization, and emission properties of a series of Pt(diphosphine)(dithiolate) complexes are reported

Reaction of Cp[sub 2]TiCl[sub 2] with donor ligands such as imidazole or PMe[sub 3] proceeds to a relatively small extent to induce reduction of Ti(IV) yielding the Ti(III) species Cp[sub 2]TiCl(L) with concurrent loss of a chlorine radical. Subsequent reaction of 3 with 1 equiv of 1,3-propanedithiol gives [Cp[sub 2]TiCl][sub 2](SCH[sub 2]CH[sub 2]CH[sub 2]S). In the presence of excess dithiol the known species [Cp[sub 2]Ti(SCH[sub 2]CH[sub 2]CH[sub 2]S)][sub 2] is formed. Related reactions of CpTiCl[sub 3] have been studied. Reaction of CpTiCl[sub 3] with PMe[sub 3] with PMe[sub 3] or PHEt[sub 2] yields the Ti(IV) adducts CpTiCl[sub 3](L) (L = PMe[sub 3], PHEt[sub 2]). Also generated in these reactions are small quantities of the reduced species CpTiCl[sub 2](L)[sub 2] (L = PMe[sub 3], PHEt[sub 2]), which were characterized by EPR spectroscopy. In similar reactions, the reduced species CpTiCl[sub 2](L)[sub 2] (L = imidazole (7c), methylimidazole (7d)) are isolated. Reaction of 7d with 1,3-propanedithiol gives the known species CpTiCl(SCH[sub 2]CH[sub 2]CH[sub 2]S). Reaction of 8 with a donor (imidazole or PMe[sub 3]) and (PhS)[sub 2] gives the product [CpTi(SCH[sub 2]CH[sub 2]S) (SPh)][sub 2]. In a similar reaction, 9 reacts with PMe[sub 3] to generate the Ti(III) species CpTi(SCH[sub 2]-CH[sub 2]CH[sub 2]S)more » (PMe[sub 3])[sub 2], which undergoes subsequent reaction with (PhS)[sub 2] to give the known product CpTi(SCH[sub 2]CH[sub 2]CH[sub 2]S)(SPh). The reactivity, structural, and electrochemical data presented herein suggest that a radical mechanism is operative in the formation of 1, 4, 8-10, and 12. Such a mechanistic proposal does offer an explanation for the previously observed [open quotes]base dependence[close quotes] of thiolate substitution reactions at Ti(IV).« less

[NBu n 4 ] 4 °W(C 3 S 5 ) 3 ] and [NBu n 4 ] 2 °Mo(C 3 S 5 ) 3 ] [C 3 S 5 2- =4,5-dimercapto-1,3-dithiole-2-thionate(2-)] were prepared. Single-crystal X-ray structure analyses revealed a distorted trigonal prismatic coordination around the metal atom for both the anion moieties. They were oxidized by [Fe(C 5 Me 5 ) 2 ][BF 4 ] to afford [Fe(C 5 Me 5 ] 2 [W(C 3 S 5 ) 3 ] and [Fe(C 5 Me 5 ) 2 ][Mo(C 3 S 5 ) 3 ], respectively

The reaction of Cp 2 ZrMe 2 with (HSCH 2 CH 2 ) 2 S affords the S 6 macrocyclic complex (Cp 2 Zr(SCH 2 CH 2 ) 2 S] 2 (5). This compound crystallizes in the orthorhombic space group Pbcn with a=15.463(5) A, b=14.049(5) A, c=14.399(5) A, V= 3128(3) A 3 , and Z=8. Related titanocene derivatives were prepared via the reaction of Cp 2 TiCl 2 with extended dithiols in the presence of base. In these cases, both monometallic and bimetallic macrocycles were formed and separated via column chromatography

Reactions of [Cr(CO) 3 (MeCN) 3 ] with S 2 C 6 R 4 2- (R=Cl, Me) yielded coordinatively and electronically unsaturated [Cr(CO) 3 (S 2 C 6 Cl 4 )] 2- , [1] 2- , and [Cr(CO) 3 (S 2 C 6 Me 4 )] 2- , [2] 2- . X-ray structure determination proved the Cr 0 center of [1] 2- to be five-coordinate and surrounded in a distorted trigonal bipyramid by three carbon and two sulfur honors. The distances indicate the double-bond character of the Cr-S bonds suggesting that the S 2 C 6 Cl 2 with ligand acts as σ-π donor such that the Cr 0 center achieves a formal 18 e - configuration.

The electrochemistry of dioxomolybdenum(VI) with the tetradentate S[sub 2](NH)[sub 2]-type ligand N,N[prime]-bis(2-mercaptophenyl)-2,3-diaminobutane (mPhabH[sub 4]), at neutral, acidic, and basic conditions, has been investigated. The molecular structure of (mPhabH[sub 2])Mo[sup VI]O[sub 2] (1) has been determined: space group P2[sub 1]2[sub 1]2[sub 1] (No. 19), a = 8.667(

Dinuclear gold(I) complexes of the type [Au 2 (μ-dithiolate)(L) n ] where L is a phosphine or bis(dialkylphosphine) have been synthesized. The molecular structures of [Au 2 (μ-S(CH 2 ) 3 S)(μ-dppm)] [dppm=bis((diphenylphosphino)methane)], [Au 2 (μ-MNT)(PPh 3 ) 2 ] (MNT=1,2-dicyanoethene- 1,2-dithiolate-S,S'), and [Au 2 (μ-S 2 C 6 H 4 )-(PPh 3 ) 2 ] are described. In addition, the structure of the tetranuclear bis(dithiolate) [Au 4 (μ-S 2 C 6 H 3 CH 3 ) 2 (PEt 3 ) 2 ] is reported.

The reactions of Ni complexes of the tridentate dithiolate ligands RN(CH 2 CH 2 S - ) 2 and S(CH 2 CH 2 S - ) 2 with O 2 leading to the formation of complexes containing one S-hound sulfinate ligand are described. Reaction of the ligands with Ni(OAc) 2 yields dinuclear [Ni(L)] 2 complexes. Reaction of these dimers with Et 4 N(CN) yields Et 4 N + salts of the four-coordinate complex anions, [Ni(L)CN] - .

The second hyperpolarizability, γ, of Ni(S 2 C 2 H 2 ) 2 (NiBDT) and some of its methyl derivatives has been computed using a well-tested semiempirical approach. The necessity of 3d functions for sulfur on the computation of γ has been documented. The factors which affect the large hyperpolarizability of NiBDT are discussed, and the contributions of the metal on the nonlinearities are commented on by considering some fragments of NiBDT and the nonlinearity of tetrathiafulvalene. The trans-dimethyl derivative ofNiBDT is shown to have a very large γ value

The novel silver(I) coordination polymer with 2,5-bis(4‘,5‘-bis(methylthio)-1‘,3‘-dithiol-2‘ylidene)-1,3,4,6-tetrathiapentalene (TTM-TTP), [Ag(TTM-TTP)(CF3SO3)]n (1), which consists of 1-D waving chains, was synthesized and characterized. Polymer 1 can be also regarded as a 3-D supramolecular network formed via many shorter side-by-side and face-to-face S···S contacts. This polymer and its iodine-doped compound 2 behave as semiconductors with σ25°C values of 7.1 × 10-6 and 0.85 S cm-1, respectively.

The reaction between (diphosphine)PtCl 2 (diphosphine=dppm, dppe, dppp, dppb, dcpe, depe) and bifunctional thiols (1,2-ethanedithiol, 1,3-propanedithiol, 1,2-benzenedithiol) in acetone or CH 2 Cl 2 gives the corresponding dithiolate complexes (1-18) in the presence of a base. These thiolato complexes have been isolated as crystalline solids and were characterized by 1 H, 13 C, and 31 P NMR spectroscopy.

Vanadium compounds exhibiting a variety of structural types are accescible from oxidative addition reactions employing low-valent vanadium reagents such as Cp 2 V and CpV(CO) 4 . The reaction of Cp 2 V with 1,3-propanedithiol yields the mononuclear V(IV) species Cp 2 V(SCH 2 CH 2 CH 2 S). This EPR-active chelate complex crytallizes in the spam group P2 1 /n.

The thiacyclophanes 2,6,10-trithia[11]-o-cyclophane, TT[11]OC, and 2,6,10-trithia[11]-m-cyclophane, TT[11]-MC, are prepared via the Cs + -mediated cyclization of (i) α,α'-dibromo-xylene and α,α'-dibromo-m-xylene with 4-thiaheptane-1,7-dithiol or (ii) o-xylene-α,α'-dithiol and m-xylene-α,α'-dithiol with 4-thiaheptane 1,7-ditosylate.

The bifunctional ligand catechol-4,5 dithiol, H(2)Dtcat, has been synthesized, and the structure of the bis Br(-) adduct, (HS)(2)C(6)H(2)(OH)(2).2Ph(4)Br.H(2)O, has been determined. The syntheses, molecular structures, electronic structures, and magnetic properties of the monoanionic [(Dtcat(2-))(2)M](-), (M = Ni, V and M = Cu, VI) complexes have been obtained as Ph(4)PBr double salts, [M(S(2)C(6)H(2)(OH)(2))(2)][Ph(4)P](3)Br(2). These and the antiferromagnetically coupled dimeric [(Dtcat)(2)Fe][Ph(4)P](2).4DMF complex, VII, have been structurally characterized. The centrosymmetric [M(S(2)C(6)H(2)(OH)(2))(2)](-) complexes in the X-ray isomorphous V and VI are connected via H-bonding to Br(-) ions to form one-dimensional chains well separated from each other by the Ph(4)P(+) cations. Magnetic measurements show V to be a S = 1/2 and VI a S = O molecules. The distribution of electrons in these compounds have been determined by density functional theory calculations which show V to be a radical anion Ni(II) complex and VI a partially oxidized-ligand, reduced-copper complex. The 4,5 dithio-o-quinone [(Dtoq)(2)Ni][Ph(4)P](2) and [(Dtoq)(2)Cu][Ph(4)P](2) orthoquinone derivatives of V and VI have been obtained by oxidation, and their molecular structures have been determined. The dimeric {[FeS(2)C(6)H(2)(OH)(2)](2)}(2-) complex, (VII) also crystallizes in chains where all OH groups participate in extensive H-bonding. The structure of the dianion VII contains S-coordinated Fe(III) ions in a square pyramidal coordination. In VII, two low spin Fe(III) (S = 1/2) sites are weakly coupled antiferromagnetically with a mu(eff) of 2.81BM at 270 K and 0.91 BM at 10 K.

The reaction of MnBr(2) and [PPN](2)[S,S-C(6)H(3)-R] (1:2 molar ratio) in THF yielded [(THF)Mn(S,S-C(6)H(3)-R)(2)](-) [R = H (1a), Me (1b); THF = tetrahydrofuran]. Formation of the dimeric [Mn(S,S-C(6)H(3)-R)(2)](2)(2-) [R = H (2a), Me (2b)] was presumed to compensate for the electron-deficient Mn(III) core via two thiolate bridges upon dissolution of complexes 1a and 1b in CH(2)Cl(2). Complex 2a displays antiferromagnetic coupling interaction between two Mn(III) centers (J = -52 cm(-1)), with the effective magnetic moment (mu(eff)) increasing from 0.85 mu(B) at 2.0 K to 4.86 mu(B) at 300 K. The dianionic manganese(II) thiolate complexes [Mn(S,S-C(6)H(3)-R)(2)](2-) [R = H (3a), Me (3b)] were isolated upon the addition of [BH(4)](-) into complexes 1a and 1b or complexes 2a and 2b, respectively. The anionic mononuclear {Mn(NO)}(5) thiolatonitrosylmanganese complexes [(NO)Mn(S,S-C(6)H(3)-R)(2)](-) [R = H (4a), Me (4b)] were obtained from the reaction of NO(g) with the anionic complexes 1a and 1b, respectively, and the subsequent reduction of complexes 4a and 4b yielded the mononuclear {Mn(NO)}(6) [(NO)Mn(S,S-C(6)H(3)-R)(2)](2-) [R = H (5a), Me (5b)]. X-ray structural data, magnetic susceptibility measurement, and magnetic fitting results imply that the electronic structure of complex 4a is best described as a resonance hybrid of [(L)(L)Mn(III)(NO(*))](-) and [(L)(L(*))Mn(III)(NO(-))](-) (L = 1,2-benzenedithiolate) electronic arrangements in a square-pyramidal ligand field. The lower IR v(NO) stretching frequency of complex 5a, compared to that of complex 4a (shifting from 1729 cm(-1) in 4a to 1651 cm(-1) in 5a), supports that one-electron reduction occurs in the {(L)(L(*))Mn(III)} core upon reduction of complex 4a.

Mono(dithiolene)sulfidomolybdenum(IV) complexes, [MoS(S4)(bdt)](2-) (2) and [MoS(S4)(bdtCl2)](2-) (3) (1,2-benzenedithiolate = bdt, 3,6-dichloro-1,2-benzenedithiolate = bdtCl2), were prepared by the substitution reaction of a tetrasulfido ligand in known [MoS(S4)2](2-) (1) with the corresponding dithiol. Complexes 2 and 3 were irreversibly oxidized to give bis(mu-sulfido) dimolybdenum(V) species, {[MoS(bdt)]2(mu-S)2}(2-) (4) and {[MoS(bdtCl2)]2(mu-S)2}(2-) (5), in aerobic acetonitrile. Mono(dithiolene)oxomolybdenum(IV) complexes, [MoO(S4)(bdt)](2-) (7) and [MoO(S4)(bdtCl2)](2-) (8), that are oxo derivatives of 2 and 3 were also synthesized from a known [MoO(S4)2](2-) (6) of an oxo derivative of 1 and the corresponding dithiol. Further, the electrophilic addition of dimethyl acetylenedicarboxylate to 7 gave [MoO(bdt)(S2C2(COOMe)2)](2-) (9), and ligand substitution of the tetrasulfido group of 7 with bdt and bdtCl2 yielded [MoO(bdt)2](2-) ( 10) and [MoO(bdt)(bdtCl2)](2-) (11), respectively. New sulfido/oxo molybdenum complexes were characterized by (1)H NMR, IR, ESI-MS, Raman, and UV-vis spectroscopies; cyclic voltammetry; and elemental analysis, and crystal structures of 2, 3, 5, 7, and 8 were determined by X-ray analysis.

A series of mononuclear (diolato)- or (dithiolato) oxomolybdenum(V) complexes, LMoO[E-(CH 2 ) n -E] (L=hydrotris(3,5-dimethyl-1-pyrazolyl) borate; E=O, S; n=2-4), and bis(alkoxo) complexes, LMoO(OR) 2 (R=Me, Et, n Pr), have been synthesized and characterized by elemental analysis, mass spectrometry, electron paramagnetic resonance spectroscopy (EPR), cyclic voltammetry, and IR and electronic absorption spectroscopy

The reactions of several arylarsenic dichlorides with the vicinal dithiols HSCH 2 CH(SH)CH 2 OH and meso-HOOCCH(SH)CH(SH)COOH (dimercaptosuccinic acid, were investigated. They readily formed five-membered rings with the dithiolate groups chelated to the arsenic (III) center. The complexes were characterized by a variety of spectroscopic techniques, which indicate that the dithiolates chelate tightly to the arsenic (III) through the sulfur atoms. The complex tolylarsenic dichloride was characterized by single-crystal X-ray diffraction. The cell is monoclinic, of space group P2 1 /n

The reaction of [(eta(6)-arene)RuCl(2)](2) (arene = C(6)Me(6), 1,4-MeC(6)H(4)CHMe(2)) with a large excess of the dianion of bis(2-mercaptoethyl) sulfide, (HSCH(2)CH(2))(2)S, obtained from deprotonation of the dithiol with freshly prepared NaOMe, gives the deep red, monomeric complexes [(eta(6)-arene)Ru(eta(3)-C(4)H(8)S(3))] (arene = C(6)Me(6) (5), 1,4-MeC(6)H(4)CHMe(2) (6)) in which the dianion is bound to the metal atom through one thioether and two thiolate sulfur atoms. Complex 5 reacts with [(eta(6)-C(6)Me(6))RuCl(2)](2) (4) in a 2:1 mole ratio to give a quantitative yield of the chloride salt of a binuclear cation [((eta(6)-C(6)Me(6))Ru)(2)Cl(mu(2)-eta(2):eta(3)-C(4)H(8)S(3))](+) (7) in which the thiolate sulfur atoms of the [(eta(6)-C(6)Me(6))Ru(eta(3)-C(4)H(8)S(3))] group bridge to a (eta(6)-C(6)Me(6))RuCl unit. This compound is also obtained directly from the reaction of 4 with the dithiolate, if the Ru dimer is used in large excess. The binuclear complex [((eta(6)-C(6)Me(6))Ru)(2)(MeCN)(mu(2)-eta(2):eta(3)-C(4)H(8)S(3))](PF(6))(2).MeCN, (9)(PF(6))(2).MeCN, is obtained by treatment of (7)Cl with NH(4)PF(6) in acetonitrile. Protonation of 5 with HCl gave the mono- and diprotonated derivatives viz. [(eta(6)-C(6)Me(6))Ru(eta(3)-C(4)H(9)S(3))]Cl, (8)Cl, and [(eta(6)-C(6)Me(6))Ru(eta(3)-C(4)H(10)S(3))]Cl(2), (10)Cl(2), respectively. The reaction of 5 with methyl iodide gives both the mono- and di-S-methylated derivatives. Treatment of 5 with dibromoalkanes, Br(CH(2))(n)Br (n = 1-5), effects ring closure to give the (eta(6)-C(6)Me(6))Ru dications containing the trithia mesocyclic zS3 (z = 8-12) ligands, isolated as their PF(6) salts. The X-ray crystal structures of 5, 6, the solvates of (7)Cl and (9)(PF(6))(2), and the trithia mesocyclic Ru complexes (eta(6)-C(6)Me(6))Ru(zS3)(PF(6))(2) (z = 8-11) are reported.

Five kinds of (1:1), (1:3), and (2:1) salts of 3-[4-(diethylmethylammonio)phenyl]-1,5-diphenyl-6-oxoverdazyl radical cation [V](+) with M(dmit)(2) anions (M = Ni, Zn, Pd, and Pt, dmit = 1,3-dithiol-2-thione-4,5-dithiolate) ([V](+)[Ni(dmit)(2)](-) (1), [V](+)[Ni(dmit)(2)](3)(-) (2), [V](+)(2)[Zn(dmit)(2)](2-) (3), [V](+)(2)[Pd(dmit)(2)](2-) (4), and [V](+)(2)[Pt(dmit)(2)](2-) (5)) and an iodide salt of [V](+) ([V](+)[I](-) (6)) have been prepared, and the magnetic susceptibilities (chi(M) values) have been measured between 1.8 and 300 K. The chi(M) of the (1:1) Ni salt (1) can be well reproduced by the sum of the contributions from (i) a Curie-Weiss system with a Curie constant (C) of 0.376 K emu/mol and a negative Weiss constant (theta) of -1.5 K and (ii) the one-dimensional Heisenberg antiferromagnetic alternating chain system with 2J(A-B)/k(B) = -274 K (alternation parameter alpha = J(A-C)/J(A-B) = 0.2). The chi(M) of the (1:3) Ni salt (2) can be well explained by the two-term contributions from (i) the Curie-Weiss system with C = 0.376 K emu/mol and theta = -5.0 K and (ii) the dimer system with 2J/k(B) = -258 K. The magnetic properties of 1 and 2 were discussed based on the results obtained by crystal structure analysis and ESR measurements of 1 and 2. The chi(M) values of the (2:1) Zn, Pd, Pt salts 3, 4, and 5 and [V](+)[I](-) salt 6 follow the Curie-Weiss law with C = 0.723, 0.713, 0.712, and 0.342 K emu/mol and theta = -2.8, -3.1, -2.6, and +0.02 K, respectively, indicating that only the spins of the verdazyl radical cation contribute to the magnetic property of these salts. The salts 1, 3, and 5 are insulators. On the other hand, the conductivity (sigma) of the Ni salt 2 and Pd salt 4 at 20 degrees C was sigma = 8.9 x 10(-2) and 1.3 x 10(-4) S cm(-)(1) with an activation energy E(A) = 0.11 and 0.40 eV, respectively. The salts 2 and 4 are new molecular magnetic semiconductors.

The chemistry of discrete metal thiolates is currently a subject of intense interest. The authors have reported that the homoleptic ethane-1,2-dithiolate (edt) complex of niobium (A)[Nb(edt)[sub 3]] (A = PPh[sub 4], NEt[sub 4], Li(thf)[sub 4]) (1) undergoes an unusual isomerization to give (A)[NbS(edt)(tpdt)] (2) (tpdt = SCH[sub 2]CH[sub 2]SCH[sub 2]CH[sub 2]S) at 70-100[degrees]C in the presence of a trace amount of water or methanol via a C-S bond cleavage of an edt ligand. This finding prompted the authors to synthesize the tpdt analogue of the complex 1 in order to examine the behavior of the tpdt ligand at the Nb(V) center. Thus the authors investigated the reaction between NbCl[sub 5], Li[sub 2](tpdt), and PPh[sub 4]Br to find that the homoleptic tpdt complexes such as [Nb(tpdt)[sub 3]][sup [minus]] and [Nb(tpdt)[sub 2]][sup +] could not be isolated. Instead, a facile C-S bond cleavage of the tpdt ligand took place to give (PPh[sub 4])[Nb(edt)[sub 2](tpdt)] (3), (PPh[sub 4])[NbS(edt)(tpdt)] (2), and (PPh[sub 4])[NbO(edt)(tpdt)] (4). This contrasts with the reaction of MoCl[sub 5] with H[sub 2](tpdt), which was reported to yield a homoleptic tpdt complex, Mo(tpdt)[sub 2]. In this paper the authors describe the isolation and X-ray structure of the seven-coordinate mixed-dithiolate complex 3 andmore » its reaction with H[sub 2](edt) to generate 1 (A = PPh[sub 4]).« less

The new ferrocene derivatives Fe(eta(5)-C(5)Me(4)SR)(2) (R = Me, 4: R = t-Bu, 5) have been prepared from the corresponding cyclopentadiene and FeCl(2). 5 may be converted to the bis(thiobenzoate) 6, a protected form of dithiol 8. From 6 the octamethyl trithiaferrocenophane 9 may be obtained in good yields. Compounds 4 and 5 are easily oxidized and form paramagnetic salts containing [M(mnt)(2)](-) anions (M = Co, Ni, Pt). The derivatives [Fe(eta(5)-C(5)Me(4)SMe)(2)][Ni(mnt)(2)], 14, [Fe(eta(5)-C(5)Me(4)SMe)(2)][Pt(mnt)(2)], 15, [Fe(eta(5)-C(5)Me(4)SMe)(2)][Co(mnt)(2)], 16, [Fe(eta(5)-C(5)Me(4)St-Bu)(2)][Ni(mnt)(2)], 17, [Fe(eta(5)-C(5)Me(4)St-Bu)(2)][Pt(mnt)(2)], 18, and [Fe(eta(5)-C(5)Me(4)St-Bu)(2)][Co(mnt)(2)], 19, have been prepared and fully characterized. X-ray crystal structural studies of 14 and 16-19 have been carried out. 14 and 16 display stacks of strongly interacting [M(mnt)(2)](-) anions, whereas 19 contains discrete [Co(mnt)(2)] dimers. 17 and 18 are isomorphous and display a typical D(+)A(-)D(+)A(-) structural motif. SQUID susceptibility measurements indicate a weak ferromagnetic ordering at low temperature for these two compounds.

The complex [Ir(H)[sub 2](HS(CH[sub 2])[sub 3]SH)(PCy[sub 3])[sub 2]]BF[sub 4] (1) which contains an unprecedented chelating dithiol ligand was prepared by the action of 1,3-propanedithiol and HBF[sub 4][center dot]Et[sub 2]O on IrH[sub 5](PCy[sub 3])[sub 2]. The acidic thiol protons of 1 (pK[sub a][approx]9) exchange much more rapidly than the hydride ligands with deuterium from MeOD. This allows a unique opportunity to measure by [sup 1]H NMR the rate constant for intramolecular H/D transfer, [Ir(H)(DSR)][sup +][r reversible] [Ir(D)(HSR)][sup +], a process which likely proceeds via an unobserved [Ir([eta][sup 2]-HD)(SR)][sup +] complex. The reaction of 1 with D[sub 2] deuterates both the thiol and hydride hydrogens; this and the observation of similar stable dihydrogen complexes support the proposal of an [eta][sup 2]-HD intermediate.

[(C 6 H 4 O 2 ) 2 GeMe][Et 4 N] cristallise dans le systeme quadratique, groupe d'espace P4 1 2 1 2 et sa structure est affinee jusqu'a R=0,045• [(MeC 6 H 3 S 2 ) 2 GeMe][Et 4 N] cristallise dans le systeme orthorhombique, groupe Pbca avec R=0,065•[(C 6 Cl 4 O 2 ) 2 GeMe][Et 4 N] cristallise dans le systeme monoclinique, groupe P2 1/c avec R=0,049

Preparation, structures et proprietes redox d'especes V-S-edt: (NEt 4 ) 3 [V 3 S 4 (edt) 3 , (NEt 4 )Na[VS(edt) 2 ] et (NEt 4 ) 2 Na[V 2 OS 4 (edt)]

Les deux complexes cristallisent dans le groupe P1 et leurs structures sont affinees jusqu'a R=5,7% et 6,8% respectivement. Coordination octaedrique autour des atomes Ir dans les deux cas

(PPh 4 )[V(OSiMe 3 )(edt) 2 ] cristallise dans le systeme triclinique, groupe d'espace P1 et sa structure est affinee jusqu'a R=0,0406