Reactions of the unsaturated hydroxo complex [W2Cp2(OH)(μ-PPh2)2(CO)]BF4 with mono- and bidentate ligands having E-H bonds (E = O, S, N).

The title compound reacted with CO at room temperature in the presence of excess HBF(4)·OEt(2) to yield a mixture of the electron-precise complexes [W(2)Cp(2)(μ-PPh(2))(2)(CO)(4)](BF(4))(2) and [W(2)Cp(2)(μ-PPh(2))(2)(CO)(3)(OH(2))](BF(4))(2), with the aquo ligand in the latter complex being easily displaced by simple donors such as acetonitrile. Reaction of the title complex with simple acidic molecules such as HSPh or HBr took place rapidly with elimination of H(2)O to give the 32-electron cations [W(2)Cp(2)(Z)(μ-PPh(2))(2)(CO)](+) [Z = Br, SPh (W-W = 2.8076(9) Å)], which were reversibly carbonylated to give the electron-precise derivatives [W(2)Cp(2)(μ-Z)(μ-PPh(2))(2)(CO)(2)](+).

Reactions of the tetrafluoroborate complex [Mo2Cp2(κ(2)-F2BF2)(μ-PPh2)2(CO)]BF4 with mono- and bidentate ligands having E-H bonds (E = O, S, Se, N, P).

The title compound reacted rapidly with CN(t)Bu at room temperature by displacing the BF(4)(-) ligand and incorporating three molecules of isocyanide to yield the electron-precise complex [Mo(2)Cp(2)(μ-PPh(2))(2)(CN(t)Bu)(3)(CO)](BF(4))(2), which was obtained as a mixture of cis and trans isomers. Reaction with several HER(n) molecules (HER(n) = HSPh, HSePh, H(2)PCy) took place with formal elimination of HBF(4) and spontaneous carbonylation to give the electron-precise cations [Mo(2)Cp(2)(μ-ER(n))(μ-PPh(2))(2)(CO)(2)](+). Reactions with several bidentate ligands (L(2)H) having acidic E-H bonds (2-hydroxypyridine, 2-mercaptopyridine, cathecol, 2-aminophenol, and 2-aminothiophenol) proceeded analogously with deprotonation of these bonds with the preference E = S > O > N.