Nature of S2Se2 sigma(4c-6e) at naphthalene 1,8-positions and models, elucidated by QTAIM dual functional analysis

摘要

The nature of extended hypervalent interactions of the E-B-*-E-A-*-E-A-*-E-B type is elucidated for 1-(8-(MeEC10H6)-E-B) E-A-E-A((C10H6EMe)-E-B-8')-1', (1 (E-A, E-B) = (S, S), 2 (S, Se), 3 (Se, S) and 4 (Se, Se)) and models AD, (R2E)-R-B-E-B...(R-A)E-A-E-A(R-A)...(ER2)-E-B-R-B (R-A, R-B = H and Me). QTAIM dual functional analysis, which we proposed recently, is applied to the analysis. Total electron energy densities H-b(r(c)) are plotted versus H-b(r(c)) - V-b(r(c))/2 for the interactions at bond critical points (BCPs; *), where V-b(r(c)) show potential energy densities at BCPs. Data for the perturbed structures around the fully optimized structures are employed for the plots, in addition to those of the fully optimized ones. While the data for the fully optimized structures are analysed by the polar coordinate (R, theta) representation, those containing the perturbed structures are by (theta(p), kappa p): theta(p) corresponds to the tangent line for the plot and kp is the curvature. While (R, q) show the static nature, (theta(p), kappa(p)) represent the dynamic nature of interactions. All E-A-*-E-A interactions in 1-4 and models A-D are classified by the shard shell interactions and have the character of a weak covalent nature. The E-A-*-E-B interactions in 1-4 are all classified by the regular closed shell interactions. They are predicted to have the typical HB (hydrogen bond) nature with covalency for 1 and 2 but the nature of the molecular complex formation through CT for 3 and 4. The E-A-*-E-B interactions in models A-D are predicted to be weaker than those in 1-4.