The motivation of this study is to investigate the interaction of Si12C12, BSi11C12, NSi11C12, BSi12C11, and NSi12C11 nanocages with Glycine amino acid (Gly). The density functional theory (DFT) and time-dependent density functional theory (TD-DFT) at the cam-B3LYP/6- 31G (p, d) level of theory by using Gaussian 09 software are utilized for this aim. The calculated results illuminate that the interaction of Gly with Si12C12, BSi11C12, NSi11C12, BSi12C11, and NSi12C11 nanocages is exothermic, and favorable in thermodynamic view. The adsorption of Gly from oxygen site (C=O) with NSi11C12 and BSi12C11 nanocage is more favorable than other complexes. The natural bonding orbital (NBO) results depicted that the electron charge transfer occur from Gly molecule toward SiC nanocage. The atom in molecule (AIM) and reduced density gradient (RDG) results confirm that the bonding between Gly and SiC nanocage is partially covalent or electrostatic type. The gap energy and global hardness of all studied complexes are lower than pure state, so the conductivity and reactivity of these complexes are more. The results of this study demonstrate that the Gly strong interact with BSi11C12, NSi11C12, BSi12C11, and NSi12C11 nanocages and the electrical structures of Gly alter significantly from pure state. These results can be considered in biological systems to investigate the effect of SiC nanocage in drug carriers and also provide information about the interaction of this nanocage with proteins in the body.
