ADDITION OF CR(CO)(5) TO THE M(ETA(2)-S-2) MOIETY OF CP(2)M(S-2)H (CP'=(T)BUC(5)H(4)M=TA - CP(X)=C(5)ME(4)ET-M=NB) AND CRYSTAL-STRUCTURES OF CP'2TAS2H-CENTER-DOT[CR(CO)(5)](N) (N=1,2)

Reaction of Cp'2TaS2H (Cp' = (t)BuC(5)H(4)) or Cp(2)(x)NbS(2)H (Cp(x) = C(5)Me(4)Et) with an excess of Cr(CO)(5)THF gives the adducts Cp'2Ta S2H . Cr(CO)(5) 1, Cp'2TaS2H . 2Cr(CO)(5) 2, and Cp(2)(x)NbS(2)H . Cr( CO)(5) 3 respectively. 1 and 2 are separated by fractional crystallisa tion. The crystal structures show the Cr(CO)(5) fragment in 1 to be co ordinated to the 'outer' sulfur, and in 2 both Cr(CO)(5) fragments are coordinated to each sulfur of the S-2 ligand in a trans fashion. In a ll cases approximate sp(3) hybridisation of the S atoms is observed. T he new compounds are thermally labile and give CO-free, trinuclear com pounds of the type Gp(4)M(2)S(4)Cr upon heating their solutions.