Gallium(III) complexes based on N,N′-bis(salicylidene)propane-1,3-diamine and its derivatives

The reactions of N,N′-bis(salicylidene)propane-1,3-diamine (salpropH2) and its substituted derivatives with Ga(acac)3 afforded the complexes [Ga(acac)(salprop)]·0.5H2O (1), [Ga(acac)(5Clsalprop)] (2), [Ga(acac)(5Brsalprop)] (3), [Ga(acac)(5NO2salprop)] (4) and [Ga(acac)(5Mesalprop)] (5), in high yields. The crystal structures of all complexes have been determined by single-crystal X-ray crystallography. All complexes are mononuclear with the Ga(III) atoms being in octahedral environments surrounded by one tetradentate chelate 5Rsalprop2− ligand and one bidentate chelate acac− ligand. The free ligands exhibit photoluminescence which was found to be increased upon complex formation. The substituted derivatives of the salpropH2 ligand bearing either electron-donating methyl groups or electron-withdrawing groups, such as Cl, Br and NO2 at the fifth position of both salicylidene rings were found to modify the emission maximum of the free ligands and the complexes.

Graphical abstractA family of mononuclear Ga(III) complexes based on N,N′-bis(salicylidene)propane-1,3-diamine (salpropH2) and its substituted derivatives has been synthesized and structurally characterized. The peripheral substitution of the salpropH2 ligand with EDGs or EWGs modulates the emission maxima of the free ligands and the complexes.Figure optionsDownload full-size imageDownload as PowerPoint slide