CHEMISTRY OF ORGANOMETALLIC METALLACYCLIC SIDE-GROUP METAL-COMPOUNDS .10. SYNTHESIS, NMR-SPECTROSCOPY AND DDTA OF THE FIRST HOMOLEPTIC METALLACYCLIC AT-COMPLEXES OF THE TYPE [LILX]2ZN(CHRCHRCHRCHR)2 (L = UNIDENTATE OR BIDENTATE LIGAND - R=H, CH3) - MOLECULAR-STRUCTURE OF [LI(TMEDA)]2ZN(CH2,CH2CH2CH2)2

The compounds [Li(Et2O)2]2Zn(CH2CH2CH2CH2)2 1, [Li2(Et2O)3] Zn(CH(CH3)CH2CH2CH2)2 7, [Li(Et2O)2]2-Zn(CH(CH3)CH2CH2CH(CH3))2 10, (Li(TMEDA)]2Zn(CH2CH(CH3)CH2CH2)2 13 and [Li2(Et2O)2.3] Zn(CH2CH-(CH3)CH(CH3)CH2)2 14, were synthesized by treatment of ZnCl2 with the dilithium compounds LiCH2CH2CH2CH2Li, LiCH(CH3)-CH2CH2CH2Li, LiCH(CH3)CH2CH2CH(CH3)Li, LiCH2CH(CH3)CH2CH2Li or LiCH2CH(CH3)CH(CH3)CH2Li in diethyl ether. Some of these complexes (7, 10) were also readily obtained by a one-pot reaction of the corresponding dichloralkanes, ZnCl2 and lithium. By substituting other n-donors for the diethyl ether in the compounds 1, 7, 10 and 14 derivatives of the composition [LiLx]2Zn(CHRCHRCHRCHR)2 (L = uni- or bidentate ligand; R = H, CH3) were obtained. The complexes were characterized by elemental and DTA analysis, many of them by H-1 and C-13 NMR spectroscopy, some of the CH3 substituted compounds also by DEPT- and two-dimensional H,C-correlated 200 MHz-NMR spectra: The results of the C-13 NMR investigations showed the beta-CH3 substituted zinc complexes to be mixtures of isomers. The crystal structure of [Li(TMEDA)]2 Zn(CH2CH2CH2CH2)2 3 was determined by an X-ray diffraction study. The crystal data and the final R values are as follows: crystal system monoclinic space group P2(1)/c (No. 14) with cell parameters a = 18.826(2) angstrom, b = 13.486(3) angstrom, c = 20.367(2) angstrom, beta = 96.12(1)-degrees, Z = 8, R = 0.061, R(w) = 0.077. The average distance Li-Zn (2.42 angstrom) of the tetrahedral complex 3 is comparable with the sum of the covalence radii of these two elements (2.48 angstrom).