Pyrrolylaldiminato complexes of Zn, Mg and Al

The reaction of 2-(2,6-iPr(2)C(6)H(3)N = CH)-5-R-C4H2NH (R = H, (LH)-H-1; R = tBu, (LH)-H-2) with one equivalent of ZnMe2 or MgnBu(2) in toluene or n-hexane afforded the bis(pyrrolylaldiminato) complexes ZnL21 (1), ZnL22 (2) and MgL22 (3). Crystalline 2 2 MgL21.THF (4THF) was formed by treatment of LiL1 with MeMgCl in THF followed by recrystallization from n-hexane. (LAlMe2)-Al-1 (6) and (LAlMe2)-Al-2 (7) were readily prepared by refluxing (LH)-H-1 and (LH)-H-2 with AlMe3 in toluene or n-hexane for several hours, However, the reaction of LiL1 with AlCl3 in a 1:1 molar ratio provided (L2AlCl)-Al-1 (8), while the reaction of KL2 with AlCl3 afforded (LAlCl2)-Al-2 (9). Compounds 2, 3, 5, and 8 were characterized by a single-crystal X-ray structural analysis. Compounds 2, 3, and 5 all have a tetrahedral geometry around the metal atom, while the five-coordinate aluminum in 8 has a trigonal bipyramidal geometry.