Synthesis and Computational Analysis of Tunable Luminescent Boron Complexes

Abstract

Light-emitting compounds are critical in many applications in modern materials. Boronthrough its unique chemistry is used to coordinate to organic ligands to activate and enhance the light-emissive properties of these ligands. We are studying Schiff-base style ligands built on the hydrazine center and various aromatic aldehydes that lead to asymmetrical ligands that contain HO••N as a chelating moiety. These asymmetrical Schiff bases are then combined with the fragments BF2 and BPh2 to make boron nitrogen adducts. We present the synthetic scheme, experimental results, and computational analysis of these compounds. It was found that through the addition of the BF2 the experimental absorption and fluorescence red shift. This is also supported through calculations both with the BF2 and BPh2 insertions. The experimental fluorescence intensity increases with the addition of BF2 due to the blocking of the Excited State Intermolecular Proton Transfer (ESIPT). One can create a tunable fluorescent boron nitrogen adduct by changing the donating and withdrawing characteristics of the starting compounds.