Luminescent Cerium(III) Complexes with Poly(mercaptoimidazolyl)borate: A New Emitter Based on S-Coordinating Ligands.

Lanthanide ions are hard Lewis acids and usually form weak bonds with soft sulfur donors, which result in the supposed instability of their complexes with S-coordinating ligands. Compared with luminescent lanthanide complexes with hard nitrogen or oxygen donor ligands, the development of luminescent lanthanide complexes based on sulfur-donor ligands currently lags behind. In this work, two types of poly(mercaptoimidazolyl)borate ligands, one is tridentate and the other is tetradentate, were used for the design and synthesis of two series of novel S-coordinating cerium(III) (Ce(III)) complexes, which were found to be not only luminescent but also with moderate to surprisingly good stability in air.