Synthesis, structures and luminescence properties of two gallium(III) complexes with 5,7-dimethyl-8-hydroxyquinoline

Abstract

Luminescent gallium(III) complexes featuring 5,7-dimethyl-8-hydroxyquinoline (DimOx) are systematically compared and their structural features are correlated with their photophysical properties. The two complexes are chemically identical; however, contain various number of solvent molecules in the crystalline lattice which is representative of the bulk material confirmed by both nuclear magnetic resonance and elemental analysis. Detailed structural comparisons highlight the effect which the solvent molecules have on the intra- and intermolecular interactions. A distinct number of interactions are found for the gallium complex (1) containing more than one solvent molecule for unit cell. Variation in complex morphology is similarly observed via SEM micrographs. The distinct luminescent properties of the two gallium complexes appear directly related to octahedral coordination of the 8-hydroxyquinoline ligand as well as the number of identical coordinated solvent molecules.

Keywords:

• Gallium
• X-ray diffraction
• 8-hydroxyquinoline
• luminescence

Acknowledgements

Financial assistance from the University of the Free State (UFS), the UFS Advanced Materials and Nanoscience Cluster, SASOL, the South African National Research Foundation (SA-NRF/THRIP) is gratefully acknowledged.