Enhancement effect of some phosphorylated compounds on fluorescence of quinazoline-based chelating ligand complexed with gallium ion

The chelating ligand, 2,4-[bis-(2,4-dihydroxybenzylidene)]-dihydrazinoquinazoline (DBHQ) can form a fluorescence complex with Ga3+ ions. The fluorescence intensity of the obtained DBHQ–Ga3+ complex increases in the presence of some phosphorylated compounds. The addition of phosphorylated serine and tyrosine, pyridoxal-5′-phosphate (PLP), and glucose-6-phosphate (G6P) leads to an increase in the fluorescence quantum yield (φ) of the complex by 1.38–1.59 times, while the addition of serine, tyrosine, pyridoxal, and glucose leads to a small increase in φ (1.02–1.04). This is the first report on the fluorescence enhancement effect of phosphorylated compounds on a Ga3+ ion complex.