Synthesis and spectroscopic properties of novel N–N linked bis-(diphenylboron) complexes†
Abstract
Novel five-membered-ring and six-membered-ring bis-(diphenylboron) complexes, consisting of hydrazine-Schiff base linked bispyrrole and two phenyl rings on the boron atoms, are readily synthesized via a facile two-step reaction. Weak intermolecular interactions are observed in the solid-state X-ray crystal structures due to the replacement of fluorine with a phenyl group at the boron atom. Both complexes exhibit high fluorescence in dilute solutions with quantum efficiencies in the range of 0.52–0.88. Because of weak intermolecular interactions and a large Stokes shift, the six-membered-ring complex 1 exhibits efficient solid-state fluorescence. However, the five-membered-ring complex 2 has a small Stokes shift, resulting in weak fluorescence in the solid-state through self-quenching. The structure–property relationships have been analyzed on the basis of X-ray crystallography, optical spectroscopy, and theoretical calculations.
- This article is part of the themed collection: Nitrogen Ligands