A deprotonation reaction of Cp2Ti(SH)2 with NaH in THF yields {Na2[CpTi(μ-S)(S)]2·4THF}2, generated by unexpected elimination of CpH. This anionic dimer is unique in that it is the first organometallic titanium species containing terminal sulfido ligands. The latter are stabilized by interactions with THF-solvated sodium cations, thus imposing a syn TiS configuration.

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The bimetallic compound [Cp*W(NO)(CH2SiMe3)](μ2-η1:η2-NC{H}SiMe3)[Cp*W(Cl)(O)] (1), is produced in low yield by the heterogeneous reaction between Cp*W(NO)(CH2SiMe3)Cl and KOCMe3 in pentane. However, when this reaction is performed in THF or Et2O, the expected metathesis product, Cp*W(NO)(CH2SiMe3)(OCMe3), is obtained. When Cp*W(NO)(CH2SiMe3)Cl is treated with KOMe in pentane, a different bimetallic compound, [Cp*W(NO)(CH2SiMe3)Cl](μ-N)[Cp*W(Cl)(η2-N{O}{H}CH2SiMe3)] (2), is produced along with the known dioxo alkyl complex Cp*W(O)2(CH2SiMe3). Again, the expected alkyl alkoxide product, Cp*W(NO)(CH2SiMe3)(OMe), is produced when the reaction is effected in THF or Et2O. The roles of KOCMe3 or KOMe during the formation of complexes 1 and 2 are presently unclear. However, when the reactions are performed using the Li or Na alkoxide salts, the expected metathesis products, namely the alkyl alkoxide complexes, are indeed produced. The solid-state molecular structures of bimetallic complexes 1 and 2 have been established by single-crystal X-ray crystallographic analyses.

. Can. J. Chem. 67,751 (1989).Synthetic methods for the preparation of PPh4 [SAr], PPN [SAr], and PPb [SeAr] (Ar = aryl; PPN = bis(tripheny1phos-phine)iminium) salts are described, and 'H NMR, infrared, and 77Se NMR spectroscopic characteriz_ation is given. The X-ray crystal structure of [PPb][Smes] (mes = 2,4,6-trimethylbenzene) was carried out: space group P1, a = 9.946(3) A, b = 10.100(2) A, c = 14.874(3) A, a = 70.19(2)", P = 69.13(2)", y = 82.54(2)", Z = 2, R = 0.100, R,, = 0.074. The structure establishes the ionic nature of this compound in the solid state, and conductance measurements in acetonitrile are consistent with 1:l electrolyte behaviour. It is shown, however, that solutions of the thiolates are quite sensitive to hydrolysis to the thiol, and also the strong nucleophilicity of the thiolate and selenolate anions enables them to react with halocarbon solvents. The selenolate solutions are extremely sensitive to oxidation to the diselenide, which limited their study. Cyclic voltammetry on selected thiolate salts shows that impurities quickly develop even in acetonitrile solvent, but comparisons with the voltammograms of thiols and disulphides confirm the assignment of an irreversible oxidation wave at ca. Ag/AgN03, 0,01 M), au processus: 2SR+ R2S2 + 2eC. Le potentiel caractCristique de cette reaction est reli6 au degrC de substitution du noyau phCnyle de l'ion SAr-. Mots clks : thiolates de phosphonium, sClCnolates de phosphonium, thiolate trimCthy1-2,4,6 benzkne de tetraphenylphosphonium.[Traduit par la revue] Introduction The recent publication of three reviews (1-3) on metal thiolate complexes is an indication of the high current interest in this area of chemistry. The subject has been of ongoing interest in our laboratory with particular emphasis on the preparation of tungsten and molybdenum thiolate complexes (4). During this work, we had occasion to examine the use of simple quaternary thiolate salts as synthetic reagents, following reports by several workers on their ability to displace both neutral and anionic ligands (5-10). Such compounds would complement the more commonly used reagents such as the alkali metal thiolates, thiol/Et,N, and the trialkylsilyl-and trialkyltin-thiolates, as a means of forming metal-thiolate bonds.The very recent publication (1 1) of an application of quaternary ammonium thiolates as initiators for the polymerization of n-butyl acrylate suggests that the possible uses of simple thiolate salts may be much wider than merely in the synthesis of metal complexes. We therefore undertook a literature search on the synthesis and characterization of both thiolates and selenolates, to establish what evidence there is for the existence of pure

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The title complex, [Mo2(OH)2(NO)2(C7H7)2(CloHIs)2], was obtained in 19% isolated yield from the treatment of [Mo(NO)(CH2 Ph)(OCMe3)(CIoH15)] in tetrahydrofuran with H2 (276 kPa). A single-crystal X-ray crystallographic analysis confirmed its bimetallic nature, the near planarity of the central Mo202 core and the monohapticity of the CH2Ph ligands. The complex is diamagnetic (XM = -517 x 10 -6 cm 3 mol -l) at room temperature and its t H NMR spectrum in C6D6 indicates that it exists as a mixture of isomers in this solution.