Synthesis, Crystal structure, weak interactions and Optical Properties of An Organic Charge-Transfer Compound―Benzyl 2-Aminopyridinium Picrate

Abstract

In this work, a new organic charge-transfer compound, 1-benzyl 2-aminopyridinium picrate, [Bz-2-NH2Py][PIC](1), was prepared and characterized by single crystal X-ray diffraction (SC-XRD), power X-ray diffraction (PXRD), FT-IR, 1HNMR and Raman spectroscopy. The title compound crystallizes in monoclinic system with space group P2(1)/c, and contains one [Bz-2-NH2Py]+ cation and one [PIC]− anion. The cations stack into a columnar structure through C–H···π interactions and the N-H∙∙∙O and C-H∙∙∙O hydrogen bonds between the anions and cations stabilize the crystal stacking of [Bz-2-NH2Py][PIC](1). The frontier molecular orbitals HOMO and LUMO were computed with DFT (using B3LYP/6-31Gþ(d, p) basis set) approach to understand the chemical reactivity and kinetic stability of the title compound. The geometrical parameters obtained from XRD experiment are good in agreement with the simulated values from single crystal structure. In addition, the organic material shows two main emission peaks about 390 and 469 nm upon excitation at 241 nm in solid state at room temperature. Hirshfeld surface analysis was performed to quantify the contributions of the different intermolecular interactions.