Experimental and theoretical investigation of [Al(PCr)(H2O)] complex in aqueous solution

Abstract

Phosphocreatine is a phosphorylated creatine molecule synthesized in the liver and transported to muscle cells where it is used for the temporary storage of energy. In Alzheimer’s disease, the capture of glucose by cells is impaired, which negatively affects the Krebs cycle, leading to problems with the generation of phosphocreatine. Furthermore, the creatine–phosphocreatine system, regulated by creatine kinase, is affected in the brains of Alzheimer’s disease patients. Aluminum ions are associated with Alzheimer’s disease. Al(III) decreases cell viability and increases the fluidity of the plasma membrane, profoundly altering cell morphology. In this study, one of the complexes formed by Al(III) and phosphocreatine in aqueous solution was investigated by potentiometry, 31P and 27Al NMR, Raman spectroscopy and density functional theory (DFT) calculations. The log KAlPCr value was 11.37±0.03. Phosphocreatine should act as a tridentate ligand in this complex. The 27Al NMR peak at 48.92ppm indicated a tetrahedral molecule. The fourth position in the arrangement was occupied by a coordinated water molecule. Raman spectroscopy, 31P NMR and DFT calculations (DFT:B3LYP/6-311++G**) indicated that the donor atoms are oxygen in the phosphate group, the nitrogen of the guanidine group and the oxygen of the carboxylate group. Mulliken charges, NBO charges, frontier molecular orbitals, electrostatic potential contour surfaces and mapped electrostatic potential were also examined.