Detection of nitrobenzene using transition metal doped C24: A DFT study

DFT investigation of temozolomide drug delivery by pure and boron doped C24 fullerene-like nanocages

In this paper, the DFT/M05-2X-D3/6-31+G(d,p) theoretical chemistry method is used to probe the adsorption ability of pure and boron doped C24 toward the temozolomide (TMZ) anticancer drug. The study is conducted in both gas and aqueous phases. The positive values of the Gibbs free energy of formation (12.03, 9.14 and 2.51 kcal mol-1) show that the adsorption of TMZ on C24 is not allowed. However, the boron-doped C24 (BC23) forms a very stable molecular complex with TMZ in the gas phase, characterized by the adsorption energy and Gibbs free energy values of -32.07 and -21.27 kcal mol-1 respectively. Analysis of Hirshfeld's atomic charge revealed the transfer of 0.6395e from TMZ to BC23, which is confirmed by the value of the dipole moment of the complex (13.42 D in the gas phase) as well as its molecular electrostatic potential map. The change in the frontier molecular orbital energy difference of BC23 is found to be 21.67% proving the good sensitivity of the cage toward the drug. The TMZ-BC23 molecular complex is very stable in water though the sensitivity of the cage is hugely reduced in that solvent. The reliability of these results was confirmed by checking the outcomes at both wB97XD/6-31+G(d,p) and B3LYP-D3/6-31+G(d,p) levels. This work shows that pristine BC23 is a better adsorbent of TMZ than some reported nanomaterials from the theoretical chemistry point of view.

Anab initiostudy of catechol sensing in pristine and transition metal decoratedγ-graphyne

Catechol is a toxic biomolecule due to its low degradability to the ecosystem and unpredictable impact on human health. In this work, we have investigated the catechol sensing properties of pristine and transition metal (Ag, Au, Pd, and Ti) decoratedγ-graphyne (GY) systems by employing the density functional theory and first-principles molecular dynamics approach. Simulation results revealed that Pd and Ti atom is more suitable than Ag and Au atom for the decoration of the GY structure with a large charge transfer of 0.29e and 1.54e from valence d-orbitals of the Pd/Ti atom to the carbon-2p orbitals of GY. The GY + Ti system offers excellent electrochemical sensing towards catechol with charge donation of 0.14e from catechol O-p orbitals to Ti-d orbitals, while the catechol molecule is physisorbed to pristine GY with only 0.04e of charge transfer. There exists an energy barrier of 5.19 eV for the diffusion of the Ti atom, which prevents the system from metal-metal clustering. To verify the thermal stability of the sensing material, we have conducted the molecular dynamics simulations at 300 K. We have reported feasible recovery times of 2.05 × 10^-5s and 4.7 × 10²s for sensing substrate GY + Pd and GY + Ti, respectively, at 500 K of UV light.

Density Functional Theory Study of Cu-Modified B12N12 Nanocage as a Chemical Sensor for Carbon Monoxide Gas

The development of efficient B₁₂N₁₂-based toxic gas sensors has received considerable attention from the scientific community. Thus, in this regard, quantum chemical calculations were performed using density functional theory (DFT) at the B97D/6-31G(d,p) level for all of the studied systems. Modification of copper on B₁₂N₁₂ results in five optimized structures, named CuB₁₁N₁₂ and B₁₂N₁₁Cu (doped structures), Cu@b₆₆ and Cu@b₆₄ (decorated structures), and Cu@B₁₂N₁₂ (encapsulated structure). The results indicate that the CO gas weakly physisorbed on the B₁₂N₁₂ nanocage. It was found that the gas adsorption performance of B₁₂N₁₂ is improved due to the introduction of the Cu atom, but the interaction between CO and B₁₂N₁₁Cu, Cu@B₁₂N₁₂, Cu@b₆₄, and Cu@b₆₆ nanocages is strong, limiting the applications as a sensor. Particularly, the CuB₁₁N₁₂ system shows moderate adsorption (E_ads = -0.6 eV) and a high electronic sensitivity (ΔE_gap = 81.6%) toward CO gas, compared to other modified systems. Furthermore, based on the sensor performance analysis, it was found that CuB₁₁N₁₂ presented low recovery time (14 ms) and high selectivity for CO detection, making it a promising fast response sensor. Finally, our results demonstrated the capability of CuB₁₁N₁₂ as a superior sensor material for applications involving the selective detection of CO gas.

Prediction and Understanding: Quantum Chemical Framework of Transition Metals Enclosed in a B12N12 Inorganic Nanocluster for Adsorption and Removal of DDT from the Environment

Emission of harmful pollutants from different sources into the environment is a major problem nowadays. Organochlorine pesticides such as DDT (C₁₄H₉Cl₅) are toxic, bio-accumulative, and regularly seen in water bodies, air, biota, and sediments. Various systems can be considered for minimizing the DDT (dichloro-diphenyl-trichloroethane) pollution. However, due to simplicity and acceptability, the adsorption method is the most popular method. Adsorption is gradually employed for the removal of both organic and inorganic pollutants found in soil and water. Thus, in this regard, efforts are being made to design inorganic nanoclusters (B₁₂N₁₂) encapsulated with late transition metals (Zn, Cu, Ni, Co, and Fe) for effective adsorption of DDT. In this context, detailed thermodynamics and quantum chemical study of all the designed systems have been carried out with the aid of density functional theory. The adsorption energy of DDT on metals cocooned in a nanocluster is found to be higher, and better adsorption energy values as compared to that of the pristine B₁₂N₁₂-DDT nanocluster have been reported. Further, analysis of the dipole moment, frontier molecular orbitals, molecular electrostatic potential plots, energy band gap, Q_NBO, and Fermi level suggested that the late-transition-metal-encapsulated inorganic B₁₂N₁₂ nanoclusters are efficient candidates for effective DDT adsorption. Lastly, the study of global descriptors of reactivity confirmed that the designed quantum mechanical systems are quite stable in nature with a good electrophilic index. Therefore, the recommendation has been made for these novel kinds of systems to deal with the development of DDT sensors.