[LI(12-CROWN-4)((ME3SI)(2)N)(2)TICH2SIME2 NSIME3] - AN ION-PAIR WITH A LINEAR LI-C-TI-AXIS

The title compound (1) has been prepared from Ti[N(SiMe3)(2)](3) and n -butyllithium in OEt2/n-hexane in the presence of 12-crown-4. Smaragd- green single crystals of 1 . C7H8 which were suitable for X-ray crysta llography were formed from toluene solutions at -18 degrees C. Accordi ng to the crystal structure determination 1 forms ion pairs between th e lithium atom and the CH2-carbon atom which is member of a planar Ti- C-Si-N heterocycle. The coordination geometry of the Li-C-Ti axis is l inear (bond angle 172.8 degrees in average of the two symmetry indepen dent species) with coordination number five at the CH2-carbon atom.