Potentiometric and multi-NMR studies of aluminum(III) complex with L-glutamate in acidic aqueous solutions.

摘要: Complex formation studies of L-glutamate with aluminum(III) ion were conducted in acidic aqueous solutions (pH 2.0-5.5) by means pH-metric titration and multinuclear (1H, 13C 27Al) NMR techniques. The following results obtained: (1) Al could weakly coordinate Glu to form various mononuclear 1:1 (AlLH2+, AlL+, AlLH-1) species dinuclear 2:1 (Al2L4+) solutions, which somewhat agreed previous findings. (2) multi-NMR spectra Al-Glu Al-Asp strongly suggest that, besides negatively charged carboxylate donors (-COO-, -COO-), the amino group can participate binding AlL+ AlLH-1 case its deprotonation, rather Al-Asp. (3) These tridentate five-+seven-membered joint chelate -NH2, -COO-) complexes exhibit an enhanced stability, help better understand biological that cross erythrocyte membrane blood-brain barrier (BBB) be deposited selectively brain regions, particularly cortex. It will also intrinsically Al’s role transamination system, is a very important process all living things.