MOLECULAR-STATES OF SULFUR-COMPOUNDS IN THE GAS-PHASE, IN SOLUTION AND IN CRYSTALS

The molecular states of selected sulfur compounds are summarized for the first time using the qualitative model approach based on topology, symmetry, effective nuclear potentials as well as electron distribution and supported by quantum chemical calculations to rationalize and to predict structure/energy relations coupled by dynamics. Topics discussed comprise: (i) The gasphase preparation of numerous short-lived sulfur compounds such as H2C=S, SN, SSO, HNSO, HC=C-HC=S and H2C=CH-HC=S, RP=S or RP(=S)(2)) and their characterization by radical cation state fingerprints. (ii) Radical ion generation of sulfur-containing species such as R(pi)(SR)(n)(.+/-), S-2(CH2)(3)(.+) or R(2)NSSNR(2)(.+) in solution by favorable AlCl3/H2CCl2 oxidation or metal mirror reduction and their characterization by ESR/ENDOR spectroscopic signal patterns. (iii) Growth of molecular crystals and structure determination of sulfur compounds and their ion salts such as the halogen charge transfer complexes {(R(pi)(SR)(n) ... Hal(2)} or the polymorphs of 2,3,7,8-tetramethoxythianthrene and its cyanine-perturbed dication [M(++)][SbCl6-](2). In addition, quantum chemical energy hypersurface calculations are reported to carefully elaborate on rotational dynamics in multi-degree of freedom compounds such as H5C6-SH or S-2(CH2)3 or reaction pathways such as the isomerisation XS=SX --> X(2)S=S or the selective thermal fragmentation of (HC=C-H2C)(2)S.