Synthesis, co-crystal structure, and DFT calculations of a multicomponent co-crystal constructed from 1H-benzotriazole and tetrafluoroterephthalic acid

Abstract

A co-crystal of 1H-benzotriazole (HB) and tetrafluoroterephthalic acid (TETA) has been successfully prepared based on N-H⋯O, O-H⋯N, and C-H⋯F hydrogen bonding interactions and characterized using single crystal X-ray diffraction. Density functional theory (DFT) calculations and vibrational spectroscopy were performed to predict the molecular structure and electronic, chemical, and vibrational properties associated with these hydrogen bonds. Quantitative electrostatic potential analysis (ESP) explained the active hydrogen bonding sites in HB and TETA, and predicted the hydrogen bonding modes in their co-crystal structure. Quantum theory of atoms in molecules (QTAIM) and reduced density gradient (RDG) analyses suggested that the hydrogen bonds present in the HB-TETA co-crystal were moderate in nature expect O-H⋯N (1.735 Å, −62.377 kJ mol−1). Meanwhile, the dnorm-mapped Hirshfeld surface of TETA can be used to understand the characteristics of the close contacts; the features were reflected in 2D fingerprint plots. Natural bond orbital (NBO) analysis of the second order perturbation theory indicated that the LP(N19)→σ∗(O5-H7) (26.76 kcal mol−1), LP(O9)→σ∗(N21-H22) (6.69 kcal mol−1), and LP(F1)→σ∗(C24-H25) (6.05 kcal mol−1) interactions were responsible for the weak interactions in the co-crystal. The structural vibrations accompanying these hydrogen bond interactions were characterized by studying the computational HB-TETA model and experimental FT-IR/FT-Raman spectra. The downward shifts observed for the CO, N-H, and O-H stretching modes after co-crystallization were attributed to the hydrogen bonds.