Tin(Ⅳ) derivatives of 2,6-pyridinedicarboxylate: A ~(119)Sn Moessbauer spectroscopic investigation

摘要

A series of organotin(Ⅳ) derivatives of 2,6-pyridinedicarboxylate has been investigated by Moessbauer spectroscopy in order to elucidate aspects concerning bonding and structural features in the solid state. A geometrical pattern of five-fold coordination at the metal centre has been revealed for SnCl_3Bu and SnClBu_3 derivatives. Trans stereochemistry for the butyl and vinyl groups of SnCl_2Bu_2 and SnCl_2(Vin)_2 derivatives has also been identified by this method. The isomer shift for the divinyl derivative is concurrent to a 7-coordinate metal centre contrasting to that for the dibutyl one. Although there is a discrepancy in isomer shift between these compounds, both have seven-fold coordination at the Sn(Ⅳ) nucleus. The resulting data has given evidence that 2,6-pyridinedicarboxylate is acting as a tridentate ligand through pyridil and carbolxylate moiety to all derivatives except for SnClBu_3. For the latter, the coordination mode occurs via carboxylate groups. The overall data support distorted geometrical pattern to all complexes in solid state.