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

Abstract

Mössbauer spectra are reported for twenty-six six-co-ordinate SnIV 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 SbV and SnIVe2qQ 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.