Theoretical study of the geometrical and electronic structures and thermochemistry of spherophanes

Abstract

A set of supramolecular cage-structuresspherophanes-was studied at the density functional B3LYP level. Full geometrical structure optimisations were made with 6-31G and 6-31G(d) basis sets followed by frequency calculations, and electronic energies were evaluated at B3LYP/6-31++G(d,p). Three different symmetries were considered: C1, Ci, and Oh. It was found that the bonds between the benzene rings are very long to allow π-electron delocalisation between them. These spherophanes show portal openings of 2.596 Å in Spher1, 4.000 Å in Meth2, 3.659 Å in Oxa3, and 4.412 Å in Thia4. From the point of view of potential host-guest interaction studies, it should also be noted that the atoms nearest to the centre of the cavities are carbons bonded to X groups. These supramolecules seem to exhibit relatively large gap HOMO−LUMO: 2.89 eV(Spher1),

Molecular hydrogen encapsulation in spherophanes

“…In our previous paper [20], we have studied, at B3LYP/6-31G and 6-31G(d), the geometrical and electronic structures of the spherophanes as well as their thermochemistry. These molecules have been found to adopt the octahedral symmetry.…”

“…The geometrical structures of the spherophanes have been optimized at B3LYP/6-31G(d) level followed by frequency calculations in an earlier paper [20]. In this study, we investigated the variation of the intermolecular interaction energy when a hydrogen molecule is inserted into or released from a spherophane host.…”

“…It has been found that this variation shows the same profile as in Scheme 3 but with very high potential barriers. In our recently published paper [20], we have found that the geometrical structure of the C 6 cycles in the spherophanes depends on the nature of the linker between the phenyl rings. The benzene rings are not planar but exhibit small distortions.…”

“…Since Spher1 has a relatively small inner cavity [20], we have proposed to study the case of the system (H 2 , Meth2) in 4H-approach, Scheme 2. The variation of the total interaction energy, E Tot (Eq.…”

“…Their electronic and geometrical structures, their thermochemistry as well as some of their spectroscopic data have been investigated at different model of computational chemistry [20]. In this work, we studied a molecular hydrogen encapsulation in these molecular cages.…”