Synthesis and study of triorganostannyl esters of 3-,4- and 3,5-pyridinylimino substituted aminobenzoic acids: Crystal structures of dimorphs of aqua-trimethyltin 3-pyridinyliminobenzoate

The synthesis and the structural investigation of triorganostannyl esters of the 3- and 4-[1-pyridin-2-yl-methylidene]- and 3,5-bis-[1-pyridin-2-yl-methylidene]-benzoic acids are reported with methyl, n-butyl, cyclohexyl, phenyl and benzyl substituents on tin. The organic carboxylates may be considered as iminopyridines emerging from the condensation of the corresponding aminobenzoic acid with pyridine-2-carboxaldehyde. In this respect it is interesting to investigate their physicochemical properties since their coordination to metal centers will affect both the photophysical properties of the metal and the conformation and intermolecular interactions of the ligands. Therefore, the structure of the above triorganotin compounds is studied and discussed in relation to those of the unsubstituted benzoates as well as of the free ligands. X-ray crystallography and a coalescence of spectroscopic methods applied both in the solid state and in solution have been used in this effort.