Structural Features of a Sulfur-Containing Group 4 Metalla[11]-crown-4 Derivative

Treatment of the ligand system (ο-C6H4OH)-S-CH2-CH2-S-(ο-C6H4-OH) (2a) with TiCl4 gave the metalla-crown ether derivative [(-S-CH2-CH2-S-)(ο-C6H4O)2]TiCl2 (5a). Complex 5a was characterized by an X-ray crystal structure analysis. It showed a pseudo-octahedral structure with both sulfur atoms being cis-coordinated to the metal center. The chloride ligands are also cispositioned, whereas the remaining two Ti−oxygen bonds are trans to each other to complete the distorted octahedral coordination geometry. The reaction of 2a with ZrCl4 gave the analogous complex 5c. The related ligand system (ο-C6H4OH)-O-CH2-CH2-O-(ο-C6H4OH) (2b) was doubly deprotonated by treatment with butyl lithium and then reacted with TiCl4 to yield the complex [(-O-CH2-CH2-O-)(ο-C6H4O)2]TiCl2 (5b).