STRUCTURAL STUDIES IN MAIN GROUP CHEMISTRY .23. ESTERTIN DERIVATIVES, STRUCTURAL AND SPECTROSCOPIC STUDIES

The crystal and molecular structures of three 'estertin' derivatives, Cl3SnCH2CH2CO2Me, Cl2Sn[CH2CH2CO2Me]2 and Cl2Sn[CH2CH2CONH2]2, are reported. Cystals of Cl3SnCH2CH2CO2Me are orthorhombic, space group P212121, with a 9.2981, b 10.5389, and c 10.0885 Å; those of Cl2Sn[CH2CH2CO2Me]2 are monoclinic, space group P21/c, with a 8.0107, b 15.9104, c 13.4109 Å, and β 131.0044°; and those of Cl2Sn[CH2CH2CONH2]2 are also monoclinic, space group Cc, with a 9.1314, b 12.8672, c 13.0317 Å, and β 126.6032°. Crystals of Cl3Sn(CH2CH2CO2Me) and Cl2Sn[CH2CH2CO2Me]2 both consist of discrete molecules, but extensive intermolecular hydrogen-bonding occurs in crystals of Cl2Sn[CH2CH2CONH2]2. Intramolecular carbonyl oxygen-to-tin coordination occurs in all three compounds. Vibrational and mass spectra are also reported, and are assigned in accordance with the determined structures. Tin-119 Mössbauer studies demonstrate that it is possible to investigate the nature of organotin additives to PVC by this method. Preliminary investigations show that Bu2Sn(IOTG)2 added to PVC undergoes only partial IOTG for chlorine exchange at the milling stage, but is completely converted to Bu2SnCl2 after thermal degradation. Both BuAcSn(IOTG)3 and BuAcSn(βMeOct)3 undergo complete sulphur ligand for Cl exchange during the milling process giving BuAcSnCl3 as the species detected. Degradation to some unidentified organotin species occurs on heating. © 1979.