Experimental, quantum chemical studies and Hirshfeld surface analysis on molecular structure of two picrate salts: 1, 4-diaza bicyclo [2,22] octane and Furan-2yl methanamine

Abstract

Two new picrate salts, namely, 1, 4-diaza bicyclo(2,2,2)octanium picrate [DABCOP] and Furan-2yl methanaminium picrate [FMP] has been successfully crystallized by Slow Evaporation Solution growth Technique (SEST). The crystal and molecular structures have been determined by single crystal X-ray diffraction method. The crystal packings of the both the crystals feature classical NH⋯O hydrogen bonds and CH⋯O interactions. In DABCOP, each diaza molecule is linked to the picric acid which forms cyclic R44(19) and R44(18) motifs. In FMP, most of the ortho related nitro group in anion are involved in NH⋯O hydrogen bonding network forming five ring R12(6), R21(4), R24(4), R12(6), and R22(5) motifs. Also, a weak CH⋯O interaction forming a dimer R22(8) motif with donor-acceptor distance of 3.413(2) Å. Based on the Hartree-Fock (HF) and Density Functional Theory (DFT) method with 6–311++G (d,p) basis set, the molecular vibrational bands were interpreted. HOMO and LUMO analysis of the molecules were calculated using corresponding methods with the same basis set. In addition, Mulliken charge analysis and thermodynamic properties were calculated. Hirshfeld surface analysis and associated two dimensional fingerprint plots show intermolecular contacts and their relative contribution via colored contour approach.