Point Defect-Mediated Electronic Tuning and Thermal Stability of Carbon-Doped Boron-Nitride Fullerenes for Radical Scavenging

Abstract

Reactive oxygen and nitrogen species (ROS/RNS) are involved in redox biology, but they remain challenging to control due to their high reactivity. This research evaluates the point defect-mediated electronic tuning of boron nitride fullerenes (BNFs) via progressive carbon (C) doping to enhance the scavenging of nitric oxide (NO) and superoxide anion (O2–). High-level density functional theory (DFT) calculations (ωB97X-D/6-311++G(d,p)) in gas and aqueous phases demonstrate that C-doping induces a transition from weak physisorption in pristine B12N12 to strong covalent chemisorption in C-doped systems when NO is adsorbed. Calculated thermodynamic functions support favorable adsorption of strongly bound complexes within the modeled temperature range. Pristine B12N12–NO remains unfavorable at 298 K. Quantum Theory of Atoms in Molecules, Electron Localization Function, and Localized Orbital Locator analyses reveal that localized spin density at the C-defect sites facilitates the formation of stable C–N and bridging C–O/B–O bonds. Finite-temperature stability was assessed using 300 K atomic density matrix propagation (ADMP) trajectories together with potential energy surface (PES)-based Langevin first-passage and mean first-passage time (MFPT) analyses. Adsorption produces system-dependent spectral redistribution, including selected near-ultraviolet/visible features and charge-transfer transitions. These results identify C-doped BNFs as theoretical metal-free radical-trapping platforms, while emphasizing the necessity of experimental validation before proposing biomedical or sensing applications.