Binuclear vanadium complexes containing sulfur and selenium ligands: The reactions of the half-sandwich compounds CpV(CO) 4 and Cp ★V(CO) 4 with dichalcogenides E 2R 2 (E = S, Se; R = Me, Ph). The X-ray crystallographic structures of Cp ★2V 2(CO) 4(μ-SR) 2 (R = Me, Ph; Cp ★ = C 5Me 5)

Abstract

Both the photo-induced reaction of CpV(CO) 4 ( 1) and Cp ★V(CO) 4 ( 1 ★) (Cp = C 5H 5, Cp ★ = C 5Me 5) with diorganochalcogenides, E 2R 2 (E = S, Se; R = Me, Ph) at room temperature in THF solution and the thermal reaction of the kinetically labile derivatives CpV(CO) 3(SMe 2) ( 7) and Cp ★V(CO) 3(SMe 2) ( 7 ★) with E 2R 2 in solution lead to binuclear, diamagnetic complexes Cp 2- and Cp 2 ★-V 2(CO) 4(μ-ER) 2 ( 8, R = Me and 9, R = Ph). In the presence of excess E 2R 2, further decarbonylation takes place to give paramagnetic Cp 2- and Cp 2 ★-V 2(μ-ER) 4 ( 10, R = Me and 11, R = Ph). With H 2S, both 1 ★ and 7 ★ can be converted into a labile intermediate Cp ★ 2V 2(CO) 4(μ-S) 2 ( 12 ★) which tends to lose the CO ligands. No carbonyl-containing intermediates were observed in the reactions of 1 ★ and 7 ★ with excess sulfur or selenium to give Cp ★ 2V 2E 5 (E = S ( 2a ★) and Se ( 2b ★)) and Cp ★ 2V 2E 4 (E = S, 3a ★ and Se, 3b ★), respectively. The carbonylvanadium complexes were characterized by their 1H, 13C and 51V NMR spectra. X-Ray crystallographic structure analyses carried out for Cp ★ 2V 2(CO) 4(μ-SMe) 2 ( 8a ★) and Cp ★ 2V 2(CO) 4(μ-SPh) 2 ( 9a ★) revealed a bent V 2(μ-SR) 2 core. The Cp ★ ligands are arranged cis to each other, and the organo substituents occupy the exo/ exo positions. The vanadium-vanadium distance is 3.083(1) Å in 8a ★ and 3.070(1) Å in 9a ★.