The influence of intermolecular interactions on the Mössbauer quadrupole splitting (Δ) of 119Sn was investigated in detail by density functional theory (DFT) calculations. Six organotin(IV) complexes [Me2Sn(acac)2 (1), Ph3SnCl (2), Me 3Sn-succinimide (3), Me3Sn-phthalimide (4), Me 3SnCl (5), and cHex3SnCl (6)] of known solid-state structures and quadrupole splittings were selected. Theoretical A values were calculated for both fully optimized geometries and experimental solid-state structures of different size, and the results were compared to the experimental A values. Compared to a synthetic procedure described in the literature for compound 4, a more convenient synthesis is reported here. The experimental A of this compound has also been redetermined at 80 K. For compounds with negligible intermolecular interactions in the solid state, calculated A values obtained did not vary significantly. In contrast, the calculated A values turned out to be very sensitive to the size of the supramolecular moiety considered in the crystal lattice. The crystal structure of compound 2 shows no significant intermolecular interactions; however, the calculated and the experimental A values remained very different, even when the supramolecular moiety considered was extended. Distortion of the coordination sphere of tin in the molecule of 2 toward a trigonal bipyramidal geometry was considered, and a possible weak intermolecular Sn⋯Cl interaction was included in the model. Steps of the distortion followed the new structure correlation function, which was found for the R3SnCl (R = alkyl, aryl) compounds. The experimental A value could be approached by this method. These results suggest that compound 2 is involved in some unexpected intermolecular interaction at 80 K.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry