Preparation and partial oxidation of tin(II) trifluoroacetate: spectroscopic properties and X-ray crystal structure of di-µ3-oxo-octakis-µ-trifluoroacetato-tetratin(II)tin(IV)

Abstract

Pure Sn (O₂CCF₃)₂ has been prepared and characterized by ¹¹⁹Sn Mössbauer and vibrational spectroscopy. A novel mixed-valence compound, Sn^II₄Sn^IVO₂(O₂CCF₃)₈, has been prepared by the partial oxidation of Sn(O₂CCF₃)₂ and characterized spectroscopically and by single-crystal X-ray diffraction (to R′= 0.0722). The crystals are tetragonal, space group I2d, with a=b= 12.448(3), c= 33.300(4)Å, and Z= 4. The structure consists of discrete non-centrosymmetric units with point group S₄, the central feature of which is a Sn^II₄Sn^IVO₂ unit containing two µ₃-oxygen atoms each of which bridge between a tin(IV) atom and two symmetry-related tin(II) atoms. The tin(IV) co-ordination is completed by trifluoroacetate groups which bridge to the tin(II) atoms. The tin(IV) and the two µ₃-oxygen atoms lie on the S₄ axis and the two Sn^II₂Sn^IVO planar units are at 90° to one another. Each pair of tin(II) atoms is bridged by two trifluoroacetates.