Synthesis and Characterization of New Cyclam-Based Zr(IV) Alkoxido Derivatives

Abstract

In this study, new mono- and di-alkoxido zirconium(IV) complexes supported by tetradentate dianionic cyclam ligands were synthesized and characterized. These compounds were obtained by reaction of the parent Zr(IV) dichlorido species with one or two equivalents of the corresponding lithium alkoxido, whereas (3,5-Me2Bn2Cyclam)Zr(OPh)2 was prepared by protonolysis of the orthometallated species (3,5-Me-C6H4CH2)2Cyclam)Zr with phenol. The solid-state molecular structures of (Bn2Cyclam)ZrCl(OtBu) and (4-tBuBn2Cyclam)Zr(OiPr)2 show a trigonal prismatic geometry around the metal centers. (Bn2Cyclam)Zr(SPh)(OtBu) and (Bn2Cyclam)ZrMe(OiPr) were prepared by reaction of (Bn2Cyclam)ZrCl(OR) (R = iPr, tBu) with one equivalent of LiSPh or MeMgCl, respectively. The reactions of (Bn2Cyclam)Zr(OiPr)2 and (4-tBuBn2Cyclam)Zr(OiPr)2 with carbon dioxide suggested the formation of species that correspond to the addition of four CO2 molecules.