Preparation and Structure of Iminopyrrolyl and Amidopyrrolyl Complexes of Group 2 Metals

Reactions of N-aryliminopyrrolyl ligand 1a, 2-(2,6-iPr2C6H3NCH)-C4H3NH (ImpDipp-H), with dibenzylcalcium gave two types of pyrrolylcalcium complexes, bis­(iminopyrrolyl)calcium (2a) and (amidopyrrolyl)­calcium (3a), via alkane elimination and ligand alkylation reaction, respectively. Preparation of a mono­(iminopyrrolyl) complex, (iminopyrrolyl)­Ca­[N­(SiMe3)2]­(THF)2 (4a), was accomplished by the addition of 1 equiv of 1a to Ca­[N­(SiMe3)2]2(THF)2. A series of group 2 metal bis­(iminopyrrolyl) complexes, [(ImpDipp)2M­(THF)3] (M = Sr (5a), Ba, (6a)) and [(ImpMe)2Ca­(THF)2] (2b) (2-(4-MeC6H4NCCH3)-C4H3NH (ImpMe-H)), was selectively prepared via amine elimination reactions, and their molecular structures were clarified by X-ray diffraction studies.