Mössbauer spectra of six-co-ordinate organotin(IV) compounds with oxygen donors: structure, bonding, and correlation with antimony(V)e2qQ values

Abstract

Mössbauer spectra are reported for twenty-six six-co-ordinate Sn^IV compounds of the type [R₂SnL₄][X]₂, (I), R₂SnL₂Cl₂, (II), and R₃SnL₂Cl, (III)(R = Me or Ph; L = oxygen donor; X = Ph₄B^–, ClO₄^–, or PF₆^–). The quadrupole splittings show that compounds (I) and (III) have trans R groups, while (III) are trans-isomers. From the derived partial quadrupole splittings, the donor properties of the ligands L increase in the order Ph₃PO < (Me₂N)₃PO < Me₂SO < ½Ph₂(O)PCH₂P(O)Ph₂ < ½Ph₂(O)PCH₂CH₂P(O)Ph₂ < HCO·NMe₂ < Ph₂(O)AsCH₂As(O)Ph₂ < Ph₃AsO < ½bipydo (bipydo = 2,2′-bipyridyl NN′-dioxide). Extension of a previous correlation between Sb^V and Sn^IVe²qQ values for SbCl₅L and corresponding cis-Cl₄SnL₂ compounds again indicates that an excellent correlation is obtained with a correlation coefficient r of 0·995 for ten compounds. This correlation further supports assumptions made in the ratio method for obtaining accurate quadrupole parameters.