Tunable luminescent boron complexes.

Abstract

The use of BF2 adducts has a long and important history in the field of auxochromic dyes, most notably in the sundry applications of the BODIPY family of dyes. Previous work in our laboratory on phenyl borinic acid yielded good emissive properties including quantum yield. BF2 was chosen due to the potential increase in the luminescence intensity of the adducts as compared to phenyl borinic acid derivatives. Simple azole based ligands were chosen due to their flexibility in color tuning. The azole N,O-type motif was found to be amenable to formation of adducts with BF2 as the oxygen readily formed a relatively stable boron ester type bond, while the non-bonding lone pair of electrons on the nitrogen is donated to the boron. Color tuning in this family of ligands is attainable through extension of the π system, or through auxochromic heteroatoms. The characterization of products included NMR, LC-APCI-MS, and X-ray crystallography. The luminescence data was collected using fluorimetry. The emissive nature of the complexes was probed using computational techniques. The TD-DFT data obtained from these computational studies was compared to the absorbance data that was obtained. The current findings as well as short-term future plans will be presented.