Structure and reactivity of mono- and dinuclear diiminate zinc alkyl complexes

The synthesis, structure and reactivity of several diiminate ligands are presented. The syntheses of five representative beta-diiminate (BDI) zinc alkyl complexes and one beta-oxo-delta-diiminate (BODDI) zinc alkyl are described. BDI ligands with varying backbone and N-aryl substituents display different solid state structures. [(BDI)ZnR] are synthesized by the reaction of (BDI)H with ZnR, in quantitative yield. Previously reported (BDI-1)ZnEt is a three-coordinate monomer in the solid state whereas [(BDI-3)ZnEt](infinity) [(BDI-3) = 2-((2,6-diisopropylphenyl)amido)-3-cyano-4-((2,6-diisopropylphenyl)imino-2-pentene] and [(BDI-4)ZnEt](infinity) [(BDI-4) = 2-((2,6-diethylphenyl)amido)-3-cyano-4-((2,6-diethylphenyl)imino-2-pentene] form one dimensional coordination polymers. The bimetallic complex [(BODDI-1)(ZnEt)(2)] [(BODDI-1) = 2,6-bis((2,6-diisopropylphenyl)amido)-2,5-heptadien-4-one] is prepared through the reaction of (BODDI-1)H-2 with two equivalents ZnEt2. Both [(BDI)ZnEt] and [(BODDI)ZnEt] complexes react with acetic acid to give the acetate complexes in moderate to high yields, offering a superior synthetic route to these complexes. [(BDI)ZnR] [BDI=(BDI-3) or 1,1,1-trifluoro-2-((2,6-diisopropylphenyl)amido)-4-((2,6-diethylphenyl)imino-2-pentene), (BDI-5)] complexes react with MeOH to produce [{(BDI)Zn(mu-OMe)}(2)Zn(mu-OMe)(2)] in moderate yields. The molecular structures of [(BDI-3)ZnEt], [(BDI-4)ZnEt], [(BODDI-1)(ZnEt)(2)], [(BODDI-1)Zn-2(mu-OAc)(2)], [{(BDI-3)Zn(mu-OMe)}(2)Zn(mu-OMe)(2)] and [{(BDI-5)Zn(mu-OMe)}(2)Zn(mu-OMe)2] have been determined by X-ray diffraction. (C) 2003 Elsevier B.V. All rights reserved.