Synthesis and structural study of an unsymmetrical aliphatic benzamidinato ligand and its use in the formation of selected Cu(i), Mg(ii) and Zr(iv) complexes

Abstract

The reaction of a Et₂O solution of LiN(Cy)SiMe₃ (Cy = cyclohexyl) with PhCN in the presence of the Lewis-base donor tetrahydrofuran (THF) or Me₂N(CH₂)₂NMe₂ (TMEDA) gave the THF- or TMEDA-solvated unsymmetrical aliphatic lithium benzamidinato compound [{PhC(NCy)(NSiMe₃)}Li(THF)]₂ (1) or [{PhC(NCy)(NSiMe₃)}Li(TMEDA)] (2). Treatment of LiN(Cy)SiMe₃ with PhCN in diethyl ether, and further with CuCl, MgBr₂(THF)₂ or ZrCl₄ at a ratio of 1 : 1, 2 : 1 and 3 : 1 allowed the formation of novel metal complexes [{PhC(NCy)(NSiMe₃)}Cu]₂ (3), [{PhC(NCy)(NSiMe₃)}₂Mg(OEt₂)] (4) and [{PhC(NCy)(NSiMe₃)}₃ZrCl] (5), respectively. The X-ray structures of complexes 1–4 are presented. Complex 5/MAO system allows the moderate polymerization of ethylene.