Intermolecular Interactions between Nitrosourea and Polyoxometalate compounds

Herein, the aim of this work was to investigate the intermolecular interactions between polyoxometalate (POMs) as a drug-delivery system with nitrosourea at different sites: CH3, COOH, NH2, NO2 and OCH3 using density functional theory (DFT) at the M062X/LanL2DZ level of theory. The result showed that, the lowest bond lengths recorded for the adsorbate and the nanocage were 1.40 angstrom, 1.64 angstrom, 1.40 angstrom and 1.57 angstrom for NU/POM(CH3), NU/POM(NH2), NU/POM(NO2) and NU/POM(OCH3) respectively. The NU/POM(NO2) system had the highest adsorption energy in the three phases: -32.039, -26.95, and -29.38 kcal/mol for gas, solvent, and benzene respectively and the lowest was shown in NU/POM(OCH3) with -14.10, -10.33, -12.29 kcal/mol. The energy gap was found to be the highest in NU/POM(NO2) with 5.061eV followed by NU/POM and NU/POM(COOH) 4.020eV and 4.003eV respectively. It has been clearly shown that NU/POM(NO2) density peak in the Highest occupied molecular orbital and Lowest unoccupied molecular orbital (HOMO/LUMO) plot was above 5 and this go in line with the electronic properties possessing a stable nature. In the NBO analysis, after adsorption of the nitrosourea (NU), the NU/POM(NO2) system recorded the highest energy with 1309.42 kcal/mol and the lowest in NU/POM(OCH3) with 921.75 kcal/mol. The system with NO2 possess more stability, chemical hardness, electrophilicity index and strong interactions. It has a better surface interaction than other compounds found in Nitrosourea.