Formation and Crystal Structure of 2,3,5-Triphenyltetrazolium Hexachlorophosphate and Dichlorophosphate(V), [TPT]+[PCl6]– and [TPT]+[PO2Cl2]–

Abstract

2,3,5-Triphenyltetrazolium hexachlorophosphate, [C19H15N4]+[PCl6]−, [TPT]+[PCl6]− (1), and 2,3,5-triphenyltetrazolium dichlorophosphate(V), [C19H15N4]+[PO2Cl2]−, [TPT]+[PO2Cl2]− (2), were synthesized by reactions of anhydrous 2,3,5-triphenyltetrazolium chloride, [TPT]+Cl−, and 2,3,5-triphenyltetrazolium chloride monohydrate [TPT]+Cl− ・H2O, with PCl5 in dry acetonitrile, and their crystal structures were determined by single-crystal X-ray diffraction analysis. In the title compounds, the [TPT]+ cations show a face-to-face stacked orientation between the phenyl rings of neighboring molecules, which is caused by intermolecular π ・ ・ ・π interactions. The crystal structure of compound 1 consists of layers of 2,3,5-triphenyltetrazolium cations and hexachlorophosphate anions. In compound 2 the tetrahedral [PO2Cl2]− anions exhibit approximate C2v symmetry with P-O bond lengths from 1.454 to 1.463 Å and P-Cl bond lengths from 2.038 to 2.050 Å . The Raman spectrum of compound 1 was recorded, and the assignment of the [PCl6]− Raman modes is proposed.