Mononuclear Tris(aminopyridinato)zirconium Alkyl, Aryl, and Alkynyl Complexes
摘要:
The reaction of 3 equiv of 4-methyl-2-((trimethylsilyl)amino)pyridine (TMS-AP-H) with (Me(2)N)(2)-ZrCl2THF)(2) or the in situ lithiation of TMS-AP-H followed by addition of ZrCl4 affords (TMS-AP)(3)Zr-Cl (1) in high yield. The X-ray analysis of 1 reveals a mononuclear zirconium 'complex coordinated by six nitrogen atoms with an overall 3-fold molecule symmetry. The eta(2)-coordinated aminopyridinato ligands arrange in a propeller-like fashion. The reactions of 1 with MeLi, phenyllithium, and (phenylethynyl)lithium afford the corresponding sigma-alkyl, -aryl, and -alkynyl complexes ((TMS-AP)(3)Zr-Me (2), (TMS-AP)(3)Zr-Ph (3), and (TMS-AP)(3)Zr-C=CPh (4). X-ray diffraction studies of 4 establish its monomeric structure, a long Zr-C bond distance, and a sterically shielded alkynyl ligand.