New N-methylimidazolium hexachloroantimonate: Synthesis, crystal structure, Hirshfeld surface and catalytic activity of in cyclopropanation of stryrene

Abstract

The N-methylimidazolium hexachloroantimonate salt Cl6Sb·C4H7N2 (MIMSb), was prepared and fully characterized. In 1H NMR spectrum, the N-H proton shifted to downfield because of the presence of SbCl6− and appears as a triplet at 13.19 ppm. Characterization with IR spectroscopy shows strong absorption band at around 699 cm−1 which is attributed to Sb−Cl stretching. Furthermore, UV–visible analysis at high concentrations in DMSO suggested that MIMSb interacts with DMSO leading to an absorption in visible region at λmax of 426 nm. Electrochemical characterization using cyclic voltammetry demonstrates three redox processes with reduction peaks at 0.69, −0.13 and −0.50 V. Finally, molecular structure of the product was determined by X-ray diffraction analysis. The crystal structure determination was carried out with Mo-Kα X-ray and data measured at 100 K. The title compound crystallizes in monoclinic P21/c space group with unit cell parameters a = 7.1131 (5) Å, b = 12.4436 (9) Å, c = 14.1658 (11) Å, V = 1241.86 (16) Å3 and Z = 4. The crystal packing is stabilized by H---Cl interaction. The analysis of intermolecular interactions was realized through the mapping of contact descriptors dnorm, shape-index and the fingerprint reveling that the most significant contribution to the Hirshfeld surface (69.4%) is from H---Cl contacts. Finally, the catalytic activity of MIMSb was probed in the cyclopropanation of styrene with ethyl diazoacetate.