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'2TaS2H . 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 crystallisation. The crystal structures show the Cr(CO)(5) fragment in 1 to be coordinated 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 all cases approximate sp(3) hybridisation of the S atoms is observed. The new compounds are thermally labile and give CO-free, trinuclear compounds of the type Gp(4)M(2)S(4)Cr upon heating their solutions.