DFT study of frontier orbitals and NLO properties of a phenanthroline and nitrophenol complex

The hydrogen-bond charge transfer complex (HB-CTC) formed between the donor, 1,10-phenanthroline (Phen), and the π-acceptor, p-nitrophenol (PNP), has been thoroughly investigated through theoretical studies. The molecular structure and the HOMO-LUMO energy gap (ΔE_H-L) of this complex have been investigated by the density functional theory. This work has studied the HB-CTC complex through FTIR, ¹HNMR, ¹³CNMR, and electronic absorption spectra. A molecular electrostatic potential surface (MESP) study allowed us to explore key aspects of intermolecular interaction. Moreover, reduced density gradient analysis was conducted to visualize valuable insights into non-covalent interactions within the complex components. Quantum Theory of Atoms in Molecules was used to analyze the interaction between the 1,10-phenanthroline and p-nitrophenol. The findings from this research not only enhance our understanding of HB-CT complexes but also highlight their exciting potential for innovative applications in various fields.