Synthesis and molecular structure of [Fe-3(mu(2)-H)(mu(3)-Te)(CO)(9)][Cp-2(#) Nb(CO)(2)] (Cp (#) = C5Me5, C5Me4Et)

Reaction of [(Cp2Nb)-Nb-#(Te2H)] (1(#)) (Cp-# =Cp* (C5Me5) or Cp-x (C5Me4Et )) with [Fe-2(CO)(9)] in boiling toluene gives [Fe-3(mu(2)-H)(mu(3)-Te)(Co) (9)][Cp-2(#) Nb(Co)(2)] (2) (Cp-# =Cp*) and (3) (Cp-# =Cp-x) in 33 and 39% yield, respectively. The crystal structure of 3 contains the already known [Fe3HTe(CO)(9)](-) anion and a [(Cp2Nb)-Nb-x(CO)(2)](+) cation in a 1:1 rat io. The latter belongs to the class of bent metallocenes in which the Nb(CO ), plain bisects the cation. For the first time, localization of the hydrog en in the solid state as a mu(2)-bridge in the cluster anion has been estab lished. (C) 2000 Elsevier Science S.A. All rights reserved.