Dinitrosylvanadiumkomplexe: [VL 4 (NO) 2 ]X, L = NCMe, THF, OCMe 2 ; X = Cl, Br, I / Dinitrosylvanadium Complexes: [VL 4 (NO) 2 ]X, L = NCMe, THF, OCMe 2 ; X = Cl, Br, I

The reaction between complexes [VH(CO) 6-n p n ] (n = 2, p n = Ph 2 P(CH 2 ) 2 PPh 2 ; n = 3, p n = MeC(CH 2 PPh 2 ) 3 ) and [CoX(NO) 2 ] 2 in THF, acetonitrile or acetone, L, yields the products cis-[VL 4 (NO) 2 ]X and [Co(CO) 3-m p n (NO)] (m = 0-3) via the intermediates [V(CO) 5-n p n (NO)] and [V(X)L 3 (NO)]X. Exclusion of X from the first coordination sphere is based on the absence of any halogen dependence of the 51 V shielding. Optimized procedures for the preparation of the hydridovanadium and dinitrosylcobalt complexes are described.