Synthesis, crystallographic structure, DFT computational studies and Hirschfeld surface analysis of a new tetranuclear anionic bromobismuthate(III): [C12H20N2]2Bi4Br16•2H2O

Abstract

• A new tetranuclear anionic bromobismuthate [C12H20N2]2Bi4Br16•2H2O was synthesized and characterized. • The X-ray crystal structure of this new complex was elucidated. • Intermolecular interactions were analyzed by Hirshfeld surface analysis. • The electrostatic potentials of the equilibrium geometry and the molecular HOMO-LUMO have been investigated. • Proton affinities, relative stabilities and the relative energies have been studied using the density functional theory (DFT). This present research makes in attention the synthesis of an organic inorganic hybrid compound with new tetranuclear anionic bromobismuthates with formula: [C 12 H 20 N 2 ] 2 Bi 4 Br 16 •2H 2 O by slow evaporation at room temperature. It is characterized by X-ray diffraction. Indeed, this compound crystallizes in the monoclinic space group; P2 1 /c with the following parameters: a = 12.3534(6), b = 24.0296(9), c = 17.8715(8) Å, β= 92.302(5)°, V = 5300.8(4) Å 3 and Z = 4. The crystal structure consists of discrete [Bi 4 Br 16 ] 4− cluster and two kinds of the 2-phenylethylpiperazinium cations. The crystal structure is stabilized through intermolecular N H…Br, C H…Br and N H…O hydrogen bonds and Br…Br interactions. The vibrational absorption bands were identified by infrared spectroscopy. Moreover, computational studies are also performed using DFT calculations at B3LYP/6311++ G (2df,2p) level of theory to understand the typical conformers of 2-phenylethylpiperazine and their proton affinities. Indeed, the molecular orbital calculations such as HOMO-LUMO and molecular electrostatic potential (MEP) surfaces have been calculated. Crystal structure analysis was supported with the Hirshfeld surface (HS) analysis and fingerprint plots enabled the identification of the significant intermolecular interactions. The Hirshfeld surface analysis of intermolecular interactions confirmed that the contacts: Br…H/H…Br and H…H make the largest contribution to the HS and play a dominant role in the crystal structure of the investigated compound.