[(CH3C)(4)N-(CH3)(2)AL...CL...AL(CH3)(2)-N(CCH3)(4)]LI - AN UNUSUAL SANDWICH COMPLEX OF LITHIUM

The title compound was prepared by addition of an equimolar amount of (CH3)(2)AlC1 to a 1:1 mixture of 2,3,4,5-tetramethyl pyrrole and lithium butanide in benzene. [{(CH3)(2)Al-N(CCH3)(4)}(2) mu- Cl]Li crystallizes in the monoclinic space group P2(1)/n with the lattice constants a 1049.7(1), b 1271.4(2), c 1796.3(2) pm, beta 98.85(1)degrees and Z = 4. In this molecule two (CH3)(2)Al-N(CCH3)(4) units are bridged by the chlorine atom and both pyrrole rings are pentahaptocoordinated to the lithium atom. The structure was refined to an R value of 0.049.