Collision-Induced Decomposition (CID) of Triangular [Mo3S7-xSex]4+ Complexes (x = 0,3,7). A liquid SIMS and FTMS/MS study of [Mo3S7-xSex(Et2NCS2)3] +

[Mo₃S(S₂)₃(dtc)₃]I, [Mo₃S(SeS)₃(dtc)₃](dtc), and [Mo₃Se(Se₂)₃(dtc)₃](dtc) (dtc = N,N-diethyldithiocarbamate) were investigated by liquid SIMS-FTMS. The fragmentation pathways were essentially the same for the three compounds and can be explained by two types of fragmentation processes: stepwise abstraction of S/Se atoms as exemplified by the series [Mo₃X_z(dtc)₃]⁺ (4 ? z ? 7, X = S, Se), and ligand dissociation, as indicated by the generation of [Mo₃X_z(dtc)₂]⁺ (5 ? z ? 7, X = S, Se). The exclusive elimination of the Se-atoms from [Mo₃S(S_ax-Se_eq)₃(dtc)₃]⁺ confirmed the inequivalent reactivity of the bridging atoms in axial and equatorial position as observed in previous studies. Collision-induced decomposition (CID) of [Mo₃S₇(dtc)₃]⁺ ( 1 ), [Mo₃S₆(dtc)₃]⁺ ( 2 ), [Mo₃S(S_ax–Se_eq)₃(dtc)₃]⁺ ( 3 ), and [Mo₃Se₇(dtc)₃]⁺ ( 4 ) revealed distinctly different fragmentation reactions for the SIMS and CID mode. CID of 1, 3 , and 4 resulted in a two-step reaction with the exclusive elimination of diatomic molecules XY (X,Y = S/Se). In the case of 3 , the selective elimination of Se₂ indicated the abstraction of two Se-atoms located in equatorial positions of two different bridging groups. This result is discussed in terms of mechanisms, based on labile M? X_eq and inert M? X_ax bonds with an intramolecular formation of a X₄ fragment prior to the elimination of X₂.     

Cation-anion interactions in [Mo<Subscript>3</Subscript>S<Subscript>7</Subscript>(Et<Subscript>2</Subscript>dtc)<Subscript>3</Subscript>](Et<Subscript>2</Subscript>dtc) solutions

Quantum chemical calculations of the [Mo₃S₇(Et₂dtc)₃](Et₂dtc) complex in different solvents are performed. It is shown that the binding energy between the cluster [Mo₃S₇(Et₂dtc)₃]⁺ cation and the outersphere (Et₂dtc)^? anion exponentially decreases with increase in the solvent dielectric permittivity. By DOSY NMR it is determined that in chloroform, the cationic and anionic moieties of the complex form an associate (contact ion pair), while in strongly polar dimethyl sulfoxide these moieties move independently of one another.     

Periphere Anbindung von Quecksilber(II)-iodid an dreikernige Molybdän-Schwefel-Dithiophosphinatocluster: [Mo3S4(R2PS2)4HgI2] (R = Et,Pr)

Peripheral Bonding of Mercury(II) Iodide to Trinuclear Molybdenum-Sulfur-Dithiophosphinato Clusters: [Mo₃S₄(R₂PS₂)₄HgI₂] (R = Et, Pr) Reaction of Mo₃S₄(R₂PS₂)₄ 1 (a : R = Et, b : R = Pr) with HgI₂ in THF yields the diamagnetic title complexes [Mo₃S₄(R₂PS₂)₄HgI₂] 3 . The crystal structure of [ 3a (H₂O)] · 2 CH₂Cl₂ shows the complexes to consist of a triangular array of Mo atoms which are bridged by μ₂? S atoms and capped by a μ₃? S atom. Each of the Mo atoms is chelated by a dithiophosphinato ligand Et₂PS₂^? and in addition two Mo atoms are bridged by a Et₂PS₂^? ligand while the H₂O molecule is bonded weakly to the third Mo atom. Thus, all Mo atoms reveal a distorted octahedral coordination sphere. HgI₂ is ?peripherally”? bonded to the cluster via two S atoms, one of which belongs to a chelating ligand and the other one to the bridging ligand. Space group P1 , lattice constants a = 12.157(2), b = 15.284(3), c = 16.049(3) Å, α = 115.56(1), β = 107.35(1), and γ = 94.62(1)°; Z = 2, d_calc = 2.23 mg/mm³; 4 236 observed reflections, R = 0.068. In organic solvents complexes 3 are strong electrolytes. VT-³¹P NMR data suggest a stepwise dissociation of 3 with formation of [Mo₃S₄(R₂PS₂)₃] ⁺[(R₂PS₂)HgI₂]^? and elimination of the bridging ligand from the cluster.     

Syntheses and structures of Tetranuclear Cluster complexes of molybdenum [Mo4(μ3-S)2(μ2-S)4 X 2-(PMe3)6] (X = SH,Cl, Br,I, SCN) and [Mo4(μ3-S)2-(μ2-S)4 (dtc)2(PMe3)4] (dtc = diethyldithiocarbamate)

A molybdenum cluster complex [Mo₄(μ₃-S)₂(μ₂-S)₄)(SH)₂(PMe_{3 6}] has been synthesized by the reaction of (NH₄)₂Mo₃S₁₃ with trimethylphosphine. The cluster core is composed of four molybdenum atoms arranged in the rhombus bridged by two capping and four bridging sulfur atoms. Two SH and six tri-methylphosphine ligands are coordinated to the terminal positions. The mean oxidation stares of molybdenum is +3.5 and there are five Mo-Mo bonds consistent with ten metal cluster electrons. The complex has been converted into [Mo₄(μ₃-S)₂(μ₂-S)₄ X ₂(PMe₃)₆] (X=Cl, Br, I, SCN) and [Mo₄μ₃-S₂(μ₂-S)₄ (die)₂(PMe₃)₄] (dtc - diethyldithiocarbamate). In the case of the dtc complex, two terminal trimetlaylphosphine ligands are displaced and dtc ligands are coordinated in chelate fashion. The structures of the SH, Cl, Br, and dtc complexes have been determined by X-ray crystallography. Molecular orbital calculations with DV-Xα method has shown large HOMO-LUMO gaps (1.52-1.74eV) for [Mo₄S₆ X ₂(PH₃)₄] (X= SH, Cl, and Br).     

Polychalkogenoanionen der Übergangsmetalle. IV. Neuartige Redoxkondensationsreaktionen von MoO2S22− in H2O und zur Darstellung von Di-μ-sulfido-Komplexen von Mov

Polychalcogenoanions of the Transition Metals. IV. Novel Redox Condensation Reactions of MoO₂S₂^2? in H₂O and Preparation of Di-μ-sulfido Complexes of Mo^v Mo^VIO₂S₂^2? polymerizes after protonation in aqueous solution under physiological conditions forming polynuclear complexes with η-S₂^2? ligands (for example [Mo₂^vO₂S₂(S₂)₂]^2?). From the solution other di-μ-sulfido Mo^v complexes as for example [Mo₂O₂S₂(Et₂dtc)₂] can be easily obtained.     

Gemischtligand-Komplexe des Rheniums. IV. Die Reaktion von [ReNCl2(Me2PhP)3] mit Dithiocarbamaten. Kristallstrukturen von trans-Chloro-dimethyldithiocarbamato-bis(dimethylphenylphosphan) nitridorhenium(V), [ReN(Cl)(Me2PhP)2(Me2dtc)], und Bis(diethyldithiocarbamato)(dimethylphenylphosphan)nitridorhenium(V), [ReN(Me2PhP)(Et2dtc)2]

Mixed-Ligand Complexes of Rhenium IV. The Reaction of [ReNCl₂(Me₂PhP)₃] with Dithiocarbamates. X-Ray Crystal Structures of trans-Chloro-dimethyldithiocarbamato-bis(dimethylphenylphosphine) nitridorhenium(V), [ReN(Cl)(Me₂PhP)₂(Me₂dtc)], and Bis(diethyldithiocarbamato)(dimethylphenylphosphine)nitridorhenium(V), [ReN(Cl)(Me₂PhP)(Et₂dtc)₂] [ReNCl₂(Me₂PhP)₃] reacts with dialkyldithiocarbamates, R₂dtc^?, under a stepwise ligand exchange. Final products of these reactions are the well-known [ReN(R₂dtc)₂] bischelates. Intermediatelly, however, complexes of the general formulae [ReN(Cl)(Me₂PhP)₂(R₂dtc)] and [ReN(Me₂PhP)(R₂dtc)₂] can be isolated. Representatives have been structurally characterized. [ReN(Cl)(Me₂PhP)₂(Me₂dtc)] crystallizes monoclinic in the space group P2₁/c, Z = 4. The dimensions of the unit cell are a = 13.071(3); b = 11.622(1); c = 15.667(3) Å; β = 97.09(1)°. The rhenium atom has a distorted octahedral environment; the Re≡N bond length is 1.71(1) Å. The Re? Cl bond distance is markedly lengthened (2.665(2) Å) as a consequence of the strong trans labilizing influence of the coordinated nitrido ligand. [ReN(Me₂PhP)(Et₂dtc)₂] crystallizes monoclinic in the space group P2₁/c, Z = 4, a = 17.262(3); b = 14.915(2); c = 9.888(2); β = 76.35(8)°. The equatorial coordination sphere is occupied by one phosphorus atom and three sulphur atoms. One of the dithiocarbamate ligands is coordinated bidentately; the second one with two distinct Re? S bond lengths. The Re? S(4) distance is 2.7983(2) Å which can be discussed as a weak interaction with the metal.     

Stepwise addition of CuBr at [(dtc)2Mo2(S)2(μ-S)2] (dtc=diethyldithiocarbamate): syntheses and crystal structures of two Mo/Cu/S clusters [(dtc)2Mo2(μ3-S)(μ-S)3(CuBr)] and [(dtc)2Mo2(μ3-S)4(CuBr)2]

Reactions of [(dtc)₂Mo₂(S)₂(μ-S)₂] with one or two equivalents of CuBr in CH₂Cl₂ afforded two new heterobimetallic sulfide clusters, [(dtc)₂Mo₂(μ₃-S)(μ-S)₃(CuBr)] (1) and [(dtc)₂Mo₂(μ₃-S)₄(CuBr)₂] (2). Both compounds were characterized by elemental analysis, IR, UV-vis and X-ray analysis. Compound 1 contains a butterfly-shaped Mo₂S₄Cu core in which one CuBr unit is coordinated by one bridging S and two terminal S atoms of the [(dtc)₂Mo₂(S)₂(μ-S)₂] moiety. In the structure of 2, one [(dtc)₂Mo₂(S)₂(μ-S)₂] moiety and two CuBr units are held together by six Cu-μ₃-S bonds, forming a cubane-like Mo₂S₄Cu₂ core.     

Tertiary phosphine-appended transition metal ferrocenyl dithiocarbamates: Syntheses,Hirshfeld surface,and electrochemical analyses

Five new heteroleptic complexes of Cu(I), Ag(I), and Ni(II) having formulae [Cu₃(dtc)₂(dppf)₂]PF₆ ( Cu-I ), [Cu₃(dtc)₂(dppe)₂]PF₆ ( Cu-II ), [Cu(PPh₃)₂(dtc)] ( Cu-III ), [Ag₃(dtc)₂(PPh₃)₂]NO₃ ( Ag-I ), and [Ni(dtc)(dppf)]PF₆ ( Ni-I ) (dtc = N-ethanol-N-methylferrocenyl-dithiocarbamate; dppf = 1,1′-bis(diphenylphosphino)ferrocene; dppe = 1,1′-bis(diphenylphosphino)ethane; PPh₃ = tripheylphosphine) have been synthesized and characterized using elemental analysis, Fourier-transform infrared, multinuclear nuclear magnetic resonance, UV–Vis spectroscopy, and single-crystal X-ray diffraction. The single-crystal X-ray diffraction studies indicate that Ag-I forms a rare trinuclear cluster in which the geometry around the two silver centers Ag1 and Ag3 is distorted tetrahedral, whereas the third silver center Ag2 shows a distorted trigonal planar geometry. The Ni-I complex has a distorted square-planar geometry around the Ni center. In addition, a side product [Ag₂{S₂(dppf)₂}] ( Ag-II ) was obtained during an attempt to synthesize [Ag(dppf)(dtc)], where the two Ag centers are bridged by two sulfido centers and coordinated with two phosphorus centers of the dppf ligand to give rise to a distorted tetrahedral geometry. The solid-state structures of Ag-I , Ni-I , and Ag-II are stabilized by a variety of weak interactions. The nature of these interactions has been addressed with the help of Hirshfeld surface analyses. In addition, the weak argentophilic interaction in Ag-I and Ag-II have been studied using quantum theory of atoms in molecules and natural bond orbital calculations. The electrochemical properties of the complexes have been investigated using cyclic voltammetry, where Cu-I and Cu-II exhibited two quasi-reversible waves, whereas Cu-III , Ag-I , Ag-II , and Ni-I exhibited only one quasi-reversible peak.     

Symmetric Ni(II) dithiocarbamates with bidentate phosphines ligands

Ni(II) mononuclear dithiocarbamate complexes with bidentate P,P ligands of composition [Ni(R₂dtc)(P,P)]X {R?=?pentyl (pe), benzyl (bz); dtc?=?S₂CN^?; P,P?=?1,2-bis(diphenylphosphino)ethane (dppe), 1,4-bis(diphenylphosphino)butane (dppb), 1,1′-bis(diphenylphosphino) ferrocene (dppf); X?=?ClO₄, Cl, Br, NCS} and binuclear complexes of composition [Ni₂(μ-dpph)(R₂dtc)₂]X₂ with a P,P-bridging ligand {P,P?=?1,6-bis(diphenylphosphino)hexane (dpph); X?=?Cl, Br, NCS} have been synthesized. The complexes have been characterized by elemental and thermal analysis, IR, electronic and ³¹P{¹H}-NMR spectroscopy, magnetochemical and conductivity measurements. Single crystal X-ray analysis of [Ni(pe₂dtc)(dppf)]ClO₄ confirmed a distorted square planar coordination in the NiS₂P₂ chromophore. For selected samples, the catalysis of graphite oxidation was studied.     

Dinuclear Molybdenum(II) Complexes with Thioether Functionalized Silylamide Ligands

Treatment of molybdenum(II) acetate with thioether functionalized silylamides R₂Si(NLi-C₆H₄–2-SR')₂ leads to the formation of dinuclear Mo^II complexes [Mo₂{R₂Si(NC₆H₄-2-SR')₂}₂]. According to X-ray crystal structure analyses the complexes [Mo₂{Me₂Si(NC₆H₄-2-SMe)₂}₂] and [Mo₂{Ph₂Si(NC₆H₄-2-SPh)₂}₂] comprise a Mo₂-unit which is coordinated by two μ-κ-N,N' silylamide ligands. The coordination sphere around the molybdenum atoms consists of two amide nitrogen atoms and two thioether sulfur atoms in a distorted square-planar arrangement. The Mo-Mo distances are 211.0(1) and 211.7(1) pm, resp. In the complex [Mo₂{Ph₂Si(NC₆H₄-2-SMe)₂}₂] the silyl amide units act as tetradentate κ-N,N',S,S'chelating ligands and the Mo-Mo distance is 218.6(1) pm.     

The crystal structure,equilibrium and spectroscopic studies of bis(dialkyldithiocarbamate) copper(II) complexes [Cu2(R2dtc)4] (dtc=dithiocarbamate)

Four copper(II) complexes of bis(dialkyldithiocarbamate) [Cd(R₂dtc)₂] (R=Me, Et, Pr, i-Pr; dtc=dithiocarbamate) have been prepared and characterized by elemental analysis, IR and ESR spectra studies. Their equilibrium constants (K), determined by a UV–vis spectrometry in EtOH, were influenced by the alkyl groups in the following order: i-Pr>n-Pr≈Et>Me. The single crystal structures of complex [Cu₂(R₂dtc)₄] have been determined using X-ray diffraction methods. The compounds [Cu₂(Et₂dtc)₄] and [Cu₂(Pr₂dtc)₄] are built of centrosymmetric neutral dimeric [Cu₂(R₂dtc)₄] entities. The copper atom lies in a distorted square–pyramidal environment. The four equatorial donors are two bidentate chelate sulfur atoms from two dtc ligands. One of the sulfur atoms from the third dtc ligand acts as a bridging ligand occupying the apical position of the symmetry-related copper atom in the dimer structure, which is viewed as two edge-sharing distorted square–pyramids. The structure of [Cu₂(i-Pr₂dtc)₄] is square planar with an exactly planar CuS₄ unit and nearly planar NCS₂ moieties. The Cu–S distances shows small decreases along the series n-Pr>Et>i-Pr, the biggest change being for the diisopropyl complex. The alkyl substituents at the nitrogen atom affect their coordination number and Cu⋯Cu distance. In the solid, [Cu₂(n-Pr₂dtc)₄] has the shortest Cu⋯Cu distance and [Cu(i-Pr₂dtc)₂] has the longest one.     

Three Heterometallic Mo–M′ Cubane-Like Tetranuclear Cluster Compounds (M′=Cu, Pb, Sb): Synthesis, Structure and Third-Order NLO Property

Three new heterometallic tetranuclear cluster compounds with a [Mo₃YS₃M] cubane-like cluster core (M=Cu, Pb, Sb; Y=O, S), [Mo₃OS₃(CuI)(-OAc)₂(dtp)₂(DMF)] (1), (dtp=S₂P(OC₂H₅)^– ₂), [Mo₃OS₃(PbI₃)(dtc)₃(py)₃] (2) (dtc=S₂CN(C₂H₅)^– ₂), [Mo₃S₄(SbI₃)(dtcpyr)₄(py)]·2H₂O (3) (dtcpyr=S₂CNC₄H^– ₈) have been synthesized and structurally characterized by IR, Raman, UV–Vis, ¹H NMR, ¹³C NMR spectroscopies and single-crystal X-ray diffraction studies. Their structure and bonding features are discussed. Compounds 1 and 2 show a good third-order optical nonlinearity, as measured by degenerate four-wave mixing technique.     

Synthesis and Characterization of Chiral Bis(aminato)iridate(I) and Aminato‐Bridged Iridium(I) Complexes

The two dinuclear Ir^I complexes [Ir₂(μ‐Cl)₂ {(R)‐(S)‐PPF‐PPh₂}₂] ( 1 ; (R)‐(S)‐PPF‐PPh₂=(S)‐1‐(diphenylphosphino)‐2‐[(R)‐1‐(diphenylphosphino)ethyl]ferrocene and [Ir₂(μ‐Cl)₂{(R)‐binap}₂] ( 3 ; (R)‐binap=(R)‐[1,1′‐binaphthalene]‐2,2′‐diylbis[diphenylphosphine]) smoothly react with 4 equiv. of the lithium salt of aniline to afford the new bis(anilido)iridate(I) (=bis(benzenaminato)iridate(1‐)) complexes Li[Ir(NHPh)₂{(R)‐(S)‐PPF‐PPh₂}] ( 4 ) and Li[Ir(NHPh)₂{(R)‐binap}] ( 5 ), respectively. The anionic complexes 4 and 5 react upon protonolysis to give the dinuclear aminato‐bridged derivatives [Ir₂(μ‐NHPh)₂{(R)‐(S)‐PPF‐PPh₂}₂] ( 6 ) and [Ir₂(μ‐NHPh)₂{(R)‐binap}₂] ( 7 ), which were characterized by X‐ray crystallography. None of the new complexes 4 – 7 shows catalytic activity in the hydroamination of olefins.     

Binuclear cluster complexes of molybdenum containing 2,2′-bipyridine and 1,10-phenanthroline: Synthesis and structure

By the interaction between (Et₄N)₂[Mo₂O₂S₈] and I₂ in DMF with a subsequent addition of 2,2′-bipyridine or 1,10-phenanthroline, new binuclear complexes [Mo₂O₂S₂I₂(bipy)₂] (1) and [Mo₂O₂S₂I₂(phen)₂] (2) are obtained. The structure of [Mo₂O₂S₂I₂(bipy)₂] is determined using single crystal X-ray diffraction. The compounds are characterized by elemental analysis and IR spectra. The [MoO(S₂)₂(bipy)] complex as a product of oxidative destruction of 1 is isolated and characterized.     

Preparation,characterization and cyclic voltammetric behaviour of dimeric sulphidomolybdenum(V) dithiocarbamate complexes

Mo₂S₄(R₂dtc)₂ (R = methyl, ethyl or benzyl; R₂ = pyrrolidinyl, piperidinyl or 4-morpholinyl) have been prepared starting from ammon     

A dinuclear molybdenum cluster containing i-mnt ligand: synthesis and crystal structure of [Mo_2S_4(i-mnt)_2] (Et_4N)_2

A dinuclear molybdenum(V) cluster compound (Et4N)2[Mo2S4(i-mnt)2] (i-mnt=l,l-dicyanoethylene-2,2-dithiol, (S2C=C(CN)2]2-) has been prepared by the ligand substitution reaction of Mo2S4(iso-pr2dtp)2 (iso-pr2dtp=S2P(OC3H7)2-) with K2(i-mnt) in the presence of Bt4NI. This cluster was characterized by inrrared spectrum, UV-Vis spectrum and single crystal structure analy-sis. The cluster anion [Mo2S4(i-mnt)2]2- possesses C, symmetry with a crystallographic mirror plane through two bridging S atoms. By the S....S supramolecular interactions between two adjacent cluster anions the [Mo2S4(i-mnt)2]2- anions are linked to form infinite chains along the b axis. Crystal data: monoclinic, space group C2/m, a=1.8748(6), b=1.5360(4), c=1.4322(5) nm, ,β=112.02(2)°, V=3.823(4) nm3, Z=4, Dc=1.50 g/cm3. The final R=0.038 and .RW=0.053 for 3015 observed unique reflections.     

Mehrkernige Molybdän- und Wolframkomplexe mit Schwefel- und Dithiophosphinatoliganden

Polynuclear Molybdenum and Tungsten Complexes with Sulfur and Dithiophosphinato Ligands Reaction of Mo(CO)₆ and disulfane [R₂P(S)]₂S₂ (R: Et, Pr, Bu) gives disulfidobridged cluster chelates [Mo₃S₇(R₂PS₂)₃]⁺ [R₂PS₂]^? 1 , the anions of which can be easily exchanged. From 1 and Ph₃P sulfido-bridged non-electrolytes [Mo₃S₄(R₂PS₂)₄] 2 are obtained, in which two Mo are additionally bridged by one R₂PS₂^?. By treatment of 2 with S₈ or disulfane 1 is regenerated. As in the conversion 1 ? 2 the formal oxidation state of Mo remains unchanged this process can be reduced to the redox reaction S₂^2? ? 1/8 S₈ + S^2?, which takes place under maintenance of the Mo₃ skeleton. Compounds 2 are coordinatively unsaturated and give 1:1 adducts with pyridine. Under modified reaction conditions M(CO)₆ and disulfane form binuclear complexes Mo₂S₄(R₂PS₂)₂ 3 resp. W₂S₄(R₂PS₂)₂ 4 , of which only 3 undergoes further reaction with M(CO)₆ and disulfane leading to 1 . The results of structural and spectroscopic investigations are reported and discussed.     

Synthesis,Crystal Structure and Stability Studies of Dithiocarbamate Complexes of Some Transition Elements (M=Co,Ni, Pd)

Single-crystal x-ray structure determinations have been recorded at 295 K for the dithiocarbamate metal compounds [Co(Et₂dtc)₃], [Co(nPr₂dtc)₃], [Pd(iPr₂dtc)₂] and [Pd(Et₂dtc)₂]. The stability constants(K) in EtOH of dialkyldithiocarbamate metal complexes [M(R₂dtc)_n] (M=Co, Ni, Pd. R=Me, Et, iPr, nPr. n=2, 3. dtc=dithiocarbamate) are determined by UV-vis data. The stability of the metal complexes increases in the order: Co<Ni<Pd. The effects of alkyl groups on the stability of [M(R₂dtc)₂] (M=Ni and Pd) increase in the order: Me<Et<nPr<iPr, and [Co(R₂dtc)₃] decrease in the order: Et>iPr>nPr>Me. The results obtained from this study confirm that the stability due to alkyl groups may be partly attributed to changes in the residual positive charge and also partly to steric hindrance of branched alkyl-groups. The comparison between the solid and solution states shows that the [M(R₂dtc)₂] (M=Pd, Ni) complexes have similar changes in M-S distance and stability with change in alkyl group. [M(iPr₂dtc)₂] has the shortest M-S distance and the highest stability in solution.     

Reactions of molybdenum and ruthenium carbonyls with some pyridylamine ligands

The interaction of Mo(CO)₆ and Ru₃(CO)₁₂ with 2-aminoethylpyridine (aepy), 2-hydrazinopyridine (hzpy) and dipicolylamine (dpa) have been investigated. Molybdenum complexes were found to have either mono- or binuclear derivatives, [MoO₂(CO)₂(aepy)] (1), [MoO₂(CO)₂(hzpy)] (2), [Mo₂O₆(aepy)₂] (3), [Mo₂O₆(hzpy)₂] (4), and [Mo₂O₄(dpa)₂] (5), depending on the reactions conditions. Ruthenium complexes are shown to have a molecular formulae of a mononuclear species; [Ru(CO)₃(aepy)] (6), [Ru(CO)₃(hzpy)] (7) and [Ru(CO)₂(dpa)] (8). The proposed structures of the complexes were elucidated using elemental analyses, i.r., u.v.–vis. and n.m.r. spectroscopy. The thermal stabilities of the reported complexes were also investigated using the t.g. technique.     

On the preparation of binuclear S,S bridged molybdenum(V) complexes crystal and molecular structure of [Mo2S4(Et2dtc)2]

MoO₄^2? is reduced by diethyldithiocarbamate (Et₂dtc^?) on prolonged digestion in aqueous medium whereby the complex [Mo₂^VO₂S₂(Et₂dtc)₂] is formed. The central moiety Mo₂O₂S₂²⁺ has a high formation tendency. When [Mo₂^V(S₂)₆]^2? is refluxed with Et₂dtc^? in ethanol, [Mo₂^VS (Et₂dtc)₂] is formed, the X-ray crystal structure of which has been determined (space group P2₁2₁2₁, a = 10.550(2) Å, b = 13.820(5) Å, c = 14.723(12) Å, d_c = 1.90 g · cm^3?, Z = 4). The Mo? Mo distance of the diamagnetic compound is 2.817(2) Å and the average Mo=S_t distance 2.099(4) Å.