Bis(μ2-2-(dimethylamino)ethoxo-N,O,O)-di(phenolato-O)ditin(II): a high-resolution single-crystal X-ray diffraction and quantum chemical study.

Experimental and calculated electron density functions ρ(r) of the title compound in the crystal were obtained. These were compared with ρ(r) for an isolated dimer. Application of the `Atoms in Molecules' theory allowed the visualization of the electron lone pair (Lp) of tin(II) and the calculation of some bond energies and all atomic charges. The stereochemical activity of the Lp was demonstrated and its volume was estimated to be approximately 10 Å(3). The energies of N→Sn and Sn-O bonds were found to be 13-18 and 25-52 kJ mol(-1). According to the experimental, AM05-PW and PBE0/6-311G(d,p) calculation data, µ(2)-2-(dimethylamino)ethoxoate accepts 0.68, 0.45 and 0.40 e from the Sn atom. Using the example of µ(2)-2-(dimethylamino)ethoxoates and complexes of bis(n-butyl)tin(IV) it was demonstrated that the more screened the Sn atom, the better the catalytic activity of its complex in polyurethane synthesis.