Tuning of the colour and chemical stability of model boranils: a strong effect of structural modifications?

Organic & Biomolecular Chemistry Pub Date: 2015-01-22 DOI: 10.1039/C4OB02545H

Abstract

A series of diarylborinic complexes with salicydeneaniline ligands bearing various functional groups at the 6-position have been synthesized in high yields by applying a straightforward one-pot multicomponent protocol. UV-Vis measurements revealed the influence of electronic character of substituents on the observed maximum of emission (λem). This has been confirmed by a relatively strong linear correlation (R2 = 0.92) of λem with Hammett σp+ constants. Such a correlation was investigated using a QTAIM analysis of the charge density distribution. Absorption and emission bands for the obtained systems span between 390–437 nm and between 506–590 nm, respectively, with quantum yields reaching 17%. Time-dependent UV-Vis absorption measurements revealed that diphenylborinic salicydeneaniline complexes undergo slow degradation in solution under ambient conditions. In contrast, the use of a naphthalene-based chromophore or the introduction of fluorinated phenyl groups at the boron atom resulted in stable systems.

Graphical abstract: Tuning of the colour and chemical stability of model boranils: a strong effect of structural modifications
Recommended Literature