Synthesis and properties of new dibenzoylmethanatoboron difluoride dyads connected by flexible siloxane linkers

Abstract A series of novel dibenzoylmethanatoboron difluoride (DBMBF2) and methoxy-substituted DBMBF2 dyads linked via flexible dimethylsiloxane linkers of variable length were synthesized and characterized. Both monomer and excimer (trough intramolecular excimer formation) emissions are observed for the dyads in dilute dichloromethane solutions at room temperature. The excimers contribution into the total fluorescence spectrum decreases with increasing siloxane linker length. The parallel-sandwich conformation of intramolecular pre-excimers formed by two terminal DBMBF2 moieties is confirmed by DFT-based calculations.