Die Kristallstrukturen von PPh₄[SnCl₃] und PPh₄[SnBr₃]/ The Crystal Structures of PPh₄[SnCl₃] and PPh₄[SnBr₃]

Abstract

Abstract PPh 4 [SnCl 3 ] and PPh 4 [SnBr 3 ] were prepared by reaction of PPh 4 X with SnX 2 in CH 2 X 2 solutions (X - Cl, Br). The vibrational spectra of the [SnX 3 ] ⊖ ions show three SnX 3 stretching frequencies, which is caused by deviations from the ideal C 3v symmetry. In the crystal structure determinations these deviations show up by slightly different Sn-X bond lengths which are explained by differing hydrogen bridges to phenyl-H atoms. The isotypic crystal structures of both compounds were determined and refined from X-ray diffraction data (R values: 0.042 and 0.034). Although triclinic (space group P1̄), the structures are closely related to the tetragonal AsPh 4 [RuNCl 4 ] structure type. Very pure SnBr 2 is prepared by the reaction of PPh 4 [SnBr 3 ] with AlBr 3 in CH 2 Br 2 solution.