Effects of Ge, Si, and B doping on the adsorption and detection properties of C60 fullerene towards methadone in gas and aqua phases: a DFT study.

Abstract

Methadone can be abused and caused addictive and has various side effects. Therefore, the development of a fast and reliable diagnosis technique for its monitoring is essential. In this work, applications of C60, GeC59, SiC59, and BC59 fullerenes were investigated utilizing density functional theory (DFT) to find a suitable probe for methadone detection. The C60 fullerene indicated weak adsorption energy for methadone sensing. Therefore, for the construction of the fullerene with good property for methadone adsorption and sensing, the GeC59, SiC59, and BC59 fullerenes have been studied. The adsorption energy of GeC59, SiC59, and BC59 in the most stable complexes were calculated at -2.08, -1.26, and -0.71eV, respectively. Although GeC59, SiC59, and BC59 all showed strong adsorption, only BC59 present a high sensitivity for detection. Further, the BC59 fullerene showing a proper short recovery time (about 1.11 × 10-6s for methadone desorption). Water as a solution is used to simulate the behavior of fullerenes in the body fluids, and results indicated that the selected pure and complex nanostructures are stable in water. The UV-vis spectrums indicated that the after adsorption of methadone on the BC59 exhibits shift toward the lower wavelengths (blue shift). Therefore, our investigation indicated that the BC59 fullerene is an excellent candidate for methadone detection. The interaction of methadone with pristine and doped C60 fullerenes surfaces was calculated using the density functional theory calculations. The GAMESS program and M06-2X method with a 6-31G(d) basis set were used for computations. Since the M06-2X method overestimates the LUMO-HOMO energy gaps (Eg) of carbon nanostructures, the HOMO and LUMO energies and Eg were investigated at the B3LYP/6-31G(d) level of theory using the optimization calculations. UV-vis spectra of excited species were obtained through the time-dependent density functional theory. To simulate the human biological fluid, the solvent phase was also evaluated in adsorption studies, and water was considered a liquid solvent.