Reactivity variations within Group 4 complexes of 1,4-di-tert-butyl-1,4-diazabuta-1,3-diene: Structures of [(C5H5)TiCl{(t-BuNCH)2}] and [(C5H5)2Zr{(t-BuNCH)2}]

The reactions of the metallocene dichlorides [(η5-C5H5)2MCl2], M = Ti and Zr, with the 1,4-di-tert-butyl-1,4-diazabuta-1,3-diene radical anion (lithium complex) in diethyl ether reveal a reactivity difference within the series, yielding [(C5H5)TiCl{(t-BuNCH)2}] and [(C5H5)2Zr{(t-BuNCH)2}] through the elimination of Li(C5H5) and/or LiCl, respectively. We report the X-ray crystal structures of these complexes, and discuss their reactivity patterns and solution fluxional properties.