DFT Studies and Crystal Structure of Synthesized 1,3-bis(2- thiophenylmethyl)-4,5-dihydroimidazolidinium hexafluorophosphate Salt

Abstract

Synthesized compound 5, (C₁₃H₁₅N₂S₂)[PF₆], was fully characterized with X-ray diffraction method. In this compound, the asymmetric unit contains a 1,3-(2-thiophenylmethyl)-4,5-dihydroimidazolidinium cation and a hexafluorophosphate anion. Due to an 180° rotation about the thiophene-CH₂ bonds, the thiophene rings in the cation are disordered [site-occupancy factors = 0.903(4)/0.097(4) and 0.837(5)/0.163(5), respectively]. The short C—N bond lengths [1.303(4) and 1.287(4) Å] in the imidazolidine ring display partial electron delocalization within the N—C—N fragment. Anion and cations are connected through intermolecular C—H...F hydrogen bonds and three p-p stacking interactions [centroid-centroid distances = 3.890(3), 3.852(5) and 3.816(7) Å] between the thiophene rings of the adjacent cations, forming layers parallel to (011). Furthermore, we studied theoretical studies of this compound, too. Geometry optimization was carried out in gas phase by Density Functional Theory (DFT) method with B3LYP applying 6-311++G^** basis set. The obtained results from experimental and theoretical structural properties of compound 5 had been compared to each other. 

Keywords

• Imidazolidinium salt
• synthesis
• crystal structure
• DFT
• C—H...F hydrogen bonds
• - stacking interactions.

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