REACTIVITY OF DIOSMACYCLES - COMPLEMENTARY SYNTHESES AND STRUCTURE OF[(MU-ETA(1),ETA(2)-CHCH2)OS2(CO)(8)][BF4]

The vinyl-bridged cationic complex, [(mu-CHCH2)Os-2(CO)(8)][BF4] (3), is obtained readily and in excellent yield either via hydride abstract ion from octacarbonyl diosmacyclobutane, (mu-eta(1),eta(1)-CH2CH2)Os-2 (CO)(8) (1), or via protonation of octacarbonyl diosmacyclobutene, (mu -eta(1),eta(1)-CHCH)Os-2(CO)(8) (2). It is argued that the H-1 and C-1 3 NMR data of complex 3 are consistent with the traditional view of bo nding in mu-alkenyl complexes, involving substantial sigma,pi donation . The solid state X-ray structure of the complex lends support for thi s formulation. Complex 3 crystallizes in the orthorhombic space group, P2(1)2(1)2(1), with a = 12.128(2) Angstrom, b = 14.151(3) Angstrom, c = 9.248(3) Angstrom, V = 1587 Angstrom(3), and Z = 4. The final R and R(W) values are 0.032 and 0.038, respectively.