SNCL2 AS A BRIDGING LIGAND IN [((CO)5M)2S N(CL)2]2- (M=CR, MO, W) - SYNTHESIS, STRUCTURE, AND REACTIVITY

[{(CO)5Cr}2Sn(Cl)2]2-, 1, may be obtained from [(CO)5Cr]2- or [(CO)5Cr SnCl2 . THF] in fair yields. Alternatively, 1 is accessible by the rea ction of [Cr2(CO)10]2- with SnCl2. This procedure may be extended to t he synthesis of [{(CO)5M}2Sn(Cl)2]2- (M = Mo, 2; M = W, 3). The compou nds 1-3 are crystallized as their alkalimetal (12-crown-4)2 or [2,2,2] cryptand salts. X-ray analyses demonstrate bridging SnCl2-moieties wit h M-Sn-M-angles close to 130-degrees in each case. The relation of the bonding situation in 1-3 to the ones observed for stannylene or ''ini dene'' complexes, respectively, is discussed. The transformation of 1 into the rhombododecahedral (X-ray analysis) Sn-O-cage compound [{(CO) 5CrSn}6(mu3-O)4(mu3-OH)4], 4, demonstrates the reactivity of the diani ons 1-3.