Structural studies in main group chemistry : XXIII. Estertin derivatives, structural and spectroscopic studies

Abstract

The crystal and molecular structures of three ‘estertin’ derivatives, Cl 3SnCH 2CH 2CO 2Me, Cl 2Sn[CH 2CH 2CO 2Me] 2 and Cl 2Sn[CH 2CH 2CONH 2] 2, are reported. Cystals of Cl 3SnCH 2CH 2CO 2Me are orthorhombic, space group P2 12 12 1, with a 9.2981, b 10.5389, and c 10.0885 Å; those of Cl 2Sn[CH 2CH 2CO 2Me] 2 are monoclinic, space group P2 1/ c , with a 8.0107, b 15.9104, c 13.4109 Å, and β 131.0044°; and those of Cl 2Sn[CH 2CH 2CONH 2] 2 are also monoclinic, space group C c , with a 9.1314, b 12.8672, c 13.0317 Å, and β 126.6032°. Crystals of Cl 3Sn(CH 2CH 2CO 2Me) and Cl 2Sn[CH 2CH 2CO 2Me] 2 both consist of discrete molecules, but extensive intermolecular hydrogen-bonding occurs in crystals of Cl 2Sn[CH 2CH 2CONH 2] 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 Bu 2Sn(IOTG) 2 added to PVC undergoes only partial IOTG for chlorine exchange at the milling stage, but is completely converted to Bu 2SnCl 2 after thermal degradation. Both BuAcSn(IOTG) 3 and BuAcSn(βMeOct) 3 undergo complete sulphur ligand for Cl exchange during the milling process giving BuAcSnCl 3 as the species detected. Degradation to some unidentified organotin species occurs on heating.