CPMD simulation of Cu2+ -- phenylalanine complex under micro-solvated environment

The study combines DFT calculations and CPMD simulations to investigate the structures of phenylalanine-copper (II) ([Phe-Cu]2+) complexes and the micro-solvation processes. ....It is found that the phenylalanine moiety appears to be in the neutral form in isolated and mono-hydrated complexes, but in the zwitterionic form in other hydrated complexes (with n no less than 2). .... The present CPMD simulations reveal that the maximum coordination of Cu2+ in the presence of the Phe ligand does not exceed four: the oxygen atoms from three water molecules and one carboxyl oxygen atom of Phe. Any excess water molecules will migrate to the second solvation shell. Moreover a unique structural motif is present in the lowest energy complexes, which is recognized to be significant in stabilizing the structures of the complexes. .....