Trianionic binucleating bis(trityl)/aryloxide ligands and their lithium, magnesium, and zinc complexes

A series of lithium complexes with trianionic bis(trityl)/aryloxide ligands were prepared by triple deprotonation of phenols with two ortho-diarylmethyl substituents. Transmetalation with one of the lithium complexes via salt metathesis resulted in the synthesis of corresponding Mg and Zn complexes, which showed distinct coordination stoichiometry and structures. The metal complexes were characterized by multi-nuclear NMR, UV-vis, and infrared spectroscopy. Additionally, the redox property of a trilithium compound was investigated by electrochemical methods. X-ray crystallography revealed that the new bis(trityl)/aryloxide ligands could simultaneously bind to two nearby metal centers both in chelating κ²-O,C fashion, making themselves rare examples of tridentate binucleating alkyl/aryloxo scaffolds. (author)