Molecular structure, electronic property and vibrational spectroscopy of C24-glycine and Gd@C24-glycine complexes.

Abstract Structure, electronic property and vibrational spectroscopy of C 24 –glycine and Gd@C 24 –glycine were systematically explored using the hybrid DFT-B3LYP functional. The interaction between empty C 24 cage and the smallest amino acid (glycine) was also investigated. It was found that the glycine molecule is energetically favorable to interact with the Mid-site on the C 24 cage through the amino nitrogen active site, rather than Top-site. The endohedral Gd atom increases the volume of the cage by around 6.7–9.8%. Analysis of frontier molecular orbitals reveals that the Gd@C 24 –glycine has the low-kinetic stability, being consistent with its thermodynamic property reflected by dissociation energy. We also see that the VIE and VEA of empty C 24 cage are slightly affected by absorbed glycine and endohedral Gd atom. Additionally, the assignments of simulated IR spectra are explored. The work may provide a theoretical reference for further application related structurally to potential antitumour activity.