Synthesis and spectroscopic studies of diorganotin derivatives with 2-[(2,6-dimethylphenyl)amino]benzoic acid. Crystal and molecular structure of the first complexes of 2-[(2,6-dimethylphenyl)amino]benzoic acid. Crystal and molecular structures of 1,2:3,4

The complexes [Bu2(DMPA)SnOSn(DMPA)Bu2]2 (2) and [Bu2Sn(DMPA)2] (3), where HDMPA is 2-[bis(2,6-dimethylphenyl)amino]benzoic acid, have been prepared and structurally characterized by means of, vibrational, ultra-violet, 1H and 13C NMR spectroscopies. The crystal structure of complexes 2 and 3 have been determined by X-ray crystallography. Three distannoxane rings are present to the dimeric tetraorganodistannoxane of planar ladder arrangement of 2. The structure is centro-symmetric and features a central rhombus Sn2O2 unit with two additional tin atoms linked at the O atoms. Five- and six-coordinated tin centers are present in the dimmer distannoxane. The crystal structure of 3 consists of discrete molecular units and the two modeprononated ligands are co-ordinated to the SnBu2 fragment. The ligands act as anisobidentate chelating agents, thus rendering the tin atom six-co-ordinated. Significant π→π, C–H-π stacking interactions and intramolecular hydrogen bonds stabilize the structures 2 and 3. The polar imino hydrogen atom participates in intramolecular hydrogen bonds. Complexes 2 and 3 are self-assembled via π→π C–H-π and stacking interactions.