Binuclear tantalum hydride complexes

Cyclopentadienyltantalum olefin or dineopentyl complexes react with molecular hydrogen to give binuclear hydride complexes, (Ta(eta/sup 5/-C/sub 5/Me/sub 4/R)Cl/sub 2/H)/sub 2/(R = Me or Et). The dimeric hydride complexes react with alkylating agents to give monoalkyl derivatives (alkyl = Me, Et, CH/sub 2/CMe/sub 3/, or CH/sub 2/SiMe/sub 3/). Ta/sub 2/(eta/sup 5/-CMe/sub 4/Et)/sub 2/Cl/sub 3/H/sub 2/(Me) crystallizes in the monoclinic space group P2/sub 1//c with a = 20.084 (6) angstrom, b = 16.972 (4) angstrom, c = 15.869 (4) angstrom, and ..beta.. = 96.86 (2)/sup 0/. The structure was solved by full-matrix least-squares techniques to R values of R/sub 1/ = 5.6% and R/sub 2/ = 7.0% for 6542 absorption-corrected reflections having /sup 2/THETA/sub MoK..cap alpha../ 3sigma(I). There are two independent molecules per asymmetric unit.