Investigation into diphosphine oxides as ligands in diorganotin(IV) adducts. Part 3. Synthesis and crystal structure of two adducts of dinitratodiphenyltin(IV) with cis- and trans-1,2-bis(diphenylphosphoryl)ethylene

Abstract

The co-ordinating properties of cis- and trans-1,2-bis(diphenylphosphoryl)ethylene (cdppoet and tdppoet respectively) have been examined in two new organotin(IV) complexes, SnPh₂(NO₃)₂(cdppoet)·CHCl₃(1) and [SnPh₂(NO₃)₂]₂(tdppoet)·2H₂O (2), on both of which an X-ray diffraction analysis was carried out. Crystals of (1) are orthorhombic, space group Pbca, with a= 17.684(4), b= 38.773(9), c= 12.092(3)Å, and c= 8. Crystals of (2) are triclinic, space group P, with a= 12.247(10),b= 12.263(11), c= 11.914(11)Åα= 99.13(7), β= 110.37(7), γ= 118.36(7)°, and Z= 1. Both structures were solved by the heavy-atom technique from diffractometer data and refined by least-squares methods to a conventional R factor of 0.0767 for (1) and 0.0344 for (2) on the basis of 2 053 and 3 655 observed reflections. The structure of both compounds closely approximates a pentagonal bipyramid about the tin atom with five O atoms in the basal plane and with two C atoms in the apical positions. The main differences between the two structures lie in the ligand behaviour of the dppoet molecule, namely bidentate chelating in (1) and bidentate bridging in (2).