sensing of NH3, NF3, NCl3 and NBr3 by using cyclic tetrapyrrole

Quantum chemical study on sensing of NH3, NF3, NCl3 and NBr3 by using cyclic tetrapyrrole


Toxic gas sensors with ultrahigh sensitivity are highly desirable and those can be achieved with the help of infinite π-conjugation of cyclic conducting polymers. In this DFT study, we demonstrate the adsorption performance of tetracyclic oligopyrrole (CTPy) for NH3 and nitrogen halides including NF3, NCl3 and NBr3. The CTPy possesses infinite conjugation and highly active cavity which provide an excellent platform for upcoming gas molecules to adsorb. Thermodynamically, the observed interaction energies of NH3, NF3, NCl3 and NBr3 analytes with CTPy at ωB97XD/6-31+ G(d,p) level of theory are -13.14, -3.00, -6.00 and -7.50 kcal/mol, respectively. In addition, the molecular dynamic simulations are performed at GFN2-xTB method to confirm the stability of CTPy and respective complexes. The SAPT0 and NCI analyses reveal that dispersion forces play a significant role in stabilizing these complexes. Moreover, the electrostatic component also contributes in stabilizing the [email protected], [email protected] and [email protected] complexes. The variation in the electronic properties including HOMO-LUMO gaps complexes along with the significant NBO charge transfer indicate the increasing conductivity of CTPy upon complexation with reported analytes. The prominent charge transfer on interaction might be due to the increasing π to π* transition, thus the λmax is shifted to longer wavelength in UV-vis spectra.

DOI: 10.1016/j.comptc.2021.113221