Tin-119 Mössbauer and nuclear magnetic resonance studies of organotin compounds. Part 2. Sterically crowded organotin halides and carboxylates

Abstract

Tin-119 Mössbauer and ¹¹⁹Sn NMR data have been obtained for a number of novel organotin halides and carboxylates containing bulky organic ligands (adamantyl, triptycyl). The Mössbauer spectra are discussed in terms of distortions from tetrahedral geometries as a result of steric crowding. The largest distortions occur for the adamantyl derivatives. A detailed study of ¹¹⁹Sn NMR shifts revealed correlations with Mössbauer quadrupole splittings and with the electronegativities of the ligands concerned. The crystal structure of (E)-(but-2-enyl)triphenyltin was determined: triclinic, space group P, with a= 9.892(3), b= 10.196(4), c= 11.637(5)Å, α= 107.16(2), β= 103.40(2), γ= 109.77(2)°. The crystals are composed of discrete non-interacting molecules. The structure was refined to R= 0.035 and R′= 0.043. The geometry around the tin centres is only slightly distorted from tetrahedral with bond angles ranging between 107.5(2) and 112.8(2)°, average 109.5°. The Sn–C(but-2-enyl) bond is significantly longer than the three Sn–C(phenyl) bonds. The structure is compared to those of other similar compounds.