A Combined Experimental and Theoretical Electron Density Study of Intra-and Intermolecular Interactions in Thiourea S,S-Dioxide

摘要

The thiourea S.S-diozide molecule is recognized as a zwitterion with a higeh dipole moment and an unusally long C-Sbond The molecule has a most interesting set of intermolecular interactions in the cryatalline state-a relativeely strong O...H-N hydrogen bond and very weak intermolecular C...S and N...O interactiions The melecule has C_s symmetry adn each oxygen atomis hydrogen-bonded to two hydrogen atoms with O...H-N distances of 2.837 and 2.826 A and angles of 176.61 and 158.38 The electron density sistribution is obtained both from X-ray diffractin data at 110 K and from a periodic density ifunctinal theory (DFT) calculation Bound characterizations is made in terms of the analysis of tological properties The covalent characters of the C-N,N-H,C-S and S-O bons are apparent and the agrement on the topological properties between experiment and theory is adequate The features of th Laplacian distributions bond paths and atomic domains are compadrable In a systematic approach DFT calculations are performed based on a monomer a dimer a heptamer and a crystal to see teh effect on the electron density distribution due to the intermolecular interactions The dipole moment of the molecule is enhanced in the solid state The typical values of rho_b and H_b of the hydrogen bonsds and weak intermolecular C...S and N...O interactions are given All the inteeractins are verified by the locatin of th bond critical point and its associated topological properties The isovalue surface to Laplacian charge density and the detailed atomic graph around each atomic site reveal the shape of the valence-shell charge concentration and provide a resonable interpretation of the bonding of each atom.