Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The ¹¹⁹Sn and ¹⁵N NMR spectra of triphenyltin(IV) oxinate and (therewith isoelectronic compound) 1-naphthoxide have been measured in the media of a non-coordinating solvent - deuteriochloroform - and two coordinating solvents - pyridine and hexamethylphosphoramide - in the temperature region from 240 to 370 K. The values of parameters of the ¹¹⁹Sn and ¹⁵N NMR spectra and their temperature dependences and comparison of the parameters of the ¹¹⁹Sn NMR spectra of the two isoelectronic compounds indicate that, in the non-coordinating solvent (deuteriochloroform), the triphenyltin(IV) oxinate forms a chelate complex with bidentate function of the oxinate ligand and with cis-trigonally bipyramidal geometry around the penta-coordinated central tin atom, whereas the triphenyltin(IV) 1-naphthoxide forms a simple compound with pseudo-tetrahedral arrangement of the substituents around the tetra-coordinated central tin atom. In both coordinating solvents chemical reactions take place which produce complexes of triphenyltin(IV) compounds with one molecule of the solvent and with trans-trigonally bipyramidal structure around the penta-coordinated central tin atom. The temperature dependences of δ(¹¹⁹Sn) chemical shifts have been used for estimation of the basic thermodynamic parameters of formation of these complexes which confirm that the formation of the complexes with coordinating solvents is - in the case of triphenyltin(IV) oxinate - connected with an exchange equilibrium consuming the original cis-chelate complex (the coordination number 5 of the central atom does not change), whereas with the 1-naphthoxide the reaction consists in a simple formation of the complex with an increase in the coordination number of the central atom (from 4 to 5).