Triorganotin(IV) esters of 2-{[N-(2-oxo-2H-naphthalene-1-yliden)hydrazo]}benzoic acid, instability of the cyclohexyl derivative

Abstract

Three triorganotin(IV) esters of 2-{[N-(2-oxo-2H-naphthalene-1-yliden)hydrazo]}benzoic acid were prepared and studied by IR and NMR spectroscopy and X-ray crystallography for the tributyl- and triethyltin(IV)-2-{[N-(2-oxo-2H-naphthalene-1-yliden)hydrazo]}benzoates (2, 3). These compounds are monomeric in solution with four-coordinate tin. The hydrazo tautomeric forms are present in chloroform solution as well as in the solid state. The coordination geometries of tin in 2 and 3 are trigonal bipyramidal with all three carbons in equatorial positions, one carboxylic oxygen and the quinone-type oxygen from adjacent molecules are in axial positions forming centrosymmetric dimers with the ring containing 20 members. The yield of the tricyclohexyltin(IV) derivative (4) is much lower than 2 or 3, with instability towards moisture in solution. The product of the reaction with water is the bis(µ²-hydroxo)-bis{2-{[N-(2-oxo-2H-naphthalene-1-yliden)hydrazo]}benzoato}tetracyclohexylditin (4a) dimer. The tin is five-coordinate in the solid state by two cyclohexyl and two hydroxy groups, the last coordination site is occupied by a monodentate carboxy group. The dimeric form of this compound remains in chloroform solution.

Keywords:

• Triorganotin(IV) esters
• Azo dye
• NMR
• X-ray

Acknowledgments

The research was supported partly by the Czech Science Foundation (grant No. 203/07/0468) and the Ministry of Education of the Czech Republic (VZ0021627501 & LC 532).