Zirconium Complexes of Two Different Iminopyrrolyl Ligands - Syntheses and Structures.

The reaction involving N-aryliminopyrrolyl ligand, 2-(( p-Me-C6H3N=CMe)-C4H3NH) ( 1a) (ImpMe-H), and Zr(O tBu)4 in a 2:1 molar ratio in toluene at 90 °C afforded the corresponding bis(iminopyrrolyl) complex of zirconium, [(ImpMe)2Zr(O tBu)2] ( 2a) having two bidentate iminopyrrole groups in the coordination sphere. In contrast, the bulkier 2-((2,6- iPr2C6H3N=CH)-C4H3NH) ( 1b) (ImpDipp-H) and Zr(O tBu)4 in a 1:1 molar ratio under the same condition yielded the corresponding mono(iminopyrrolyl) complex of zirconium, [(ImpDipp)Zr(O tBu)3(THF)] ( 2b), which contains only one bidentate iminopyrrole moiety in the coordination sphere. Both complexes were characterized by single-crystal X-ray diffraction analysis. The solid-state structures reveal that the bulky iminopyrrole ligands cause a steric crowding around the zirconium ion along with three tert-butoxide ligands attached to the central metal atom. [ABSTRACT FROM AUTHOR]