名称:
Binuclear CpV, Cp*V, and Cp*Ta Complexes containing Organochalcogenolato Bridges, μ-ER (E = Sulfur, Selenium, Tellurium; R = Methyl, Phenyl, and Ferrocenyl)
摘要:
Photolysis of the halfsandwich tetracarbonylmetal complexes CpV(CO)(4), Cp*V(CO)(4) and Cp*Ta(CO)(4) in solution in the presence of di(organyl)dichalcogenides E2R2 (E = S, Se, Te; R = Me, Ph, Fc) leads to diamagnetic doubly organochalcogenolato-bridged compounds, [(CpM)-M-0(CO)(2)(mu-ER)](2). According to the X-ray structure determinations carried out for [CpV(CO)-L(mu-TeMe)](2), [Cp*V(CO)(2)(mu-TePh)](2) and [Cp*Ta(CO)(2)(mu-SPh)](2), the molecular framework consists of a folded M-2(mu-ER)(2) ring with the cyclopentadienyl ligands in cis-configuration and the organyl substituents R in a syn-equatorial arrangement, thus forming a bowl-shaped molecule with the four terminal CO ligands protruding into the inner sphere. The M ... M distances (in the range between 305 and 330 pm) are not considered to indicate direct bonding interactions. The vanadium complexes [(CpV)-V-0(CO)(2)(mu-ER)](2) are completely decarbonylated in the presence of an excess of E2R2 in boiling toluene, and in many cases the paramagnetic quadruply-bridged products, [CpV(mu-ER)(2)](2), can be isolated.