Geometrical And Energetic Characteristics Of Semidline Horizontal Ellipsisse Interactions In Crystal Structures Of Organoselenium Molecules

Non-covalent selenium-selenium interactions between selenium-containing organic molecules were studied in crystal structures from the Cambridge Structural Database and by high-level quantum chemical calculations. SeMIDLINE HORIZONTAL ELLIPSISSe contacts in the crystal structures were analyzed, and the most frequent patterns were identified and used to design the model systems for quantum chemical calculations. The strongest calculated SeMIDLINE HORIZONTAL ELLIPSISSe interaction (Delta E-CCSD(T)/CBS = -2.31 kcal mol(-1)) was identified in the model system with a mutual parallel orientation of interacting molecules. In the crystal structures, this orientation of molecules is predominant. In the geometry with the sigma-hole bonding, the interaction is somewhat weaker (Delta E-CCSD(T)/CBS = -2.13 kcal mol(-1)). NCI analysis showed that SeMIDLINE HORIZONTAL ELLIPSISSe interaction in the most stable geometries is further enhanced by hydrogen bonding of Se-HMIDLINE HORIZONTAL ELLIPSISSe or C-HMIDLINE HORIZONTAL ELLIPSISSe type. The results of energy decomposition analysis (SAPT) calculations revealed that the nature of the SeMIDLINE HORIZONTAL ELLIPSISSe interaction is predominantly dispersive with a strong electrostatic contribution. The results of the energy decomposition analysis also suggest that the electrostatic component has a crucial role in defining the geometry of selenium-selenium interactions due to their directional nature.