Assessing the Possibility and Properties of Types I and II Chalcogen Bonds

Type I and II halogen bonds are well-recognized motifs that commonly occur within crystals. Quantum calculations applied to examine whether such geometries might in their closely related chalcogen bond cousins. Homodimers constructed of the R1R2C=Y R1R2Y monomers, wherein Y represents a atom, S, Se, or Te; R1 R2 refer either H F. A (T2) geometry lone pair one is aligned with σ-hole its partner stable arrangement for all except YH2, although not structures true minima. The symmetric T1 which each atom serves as both electron donor acceptor slightly higher energy R1R2C=Y, but reverse R1R2Y. Due deeper σ-holes, latter molecules engage stronger than do former, exception H2Y, whose dimers barely bound. interaction energies rise grows larger: S < Se Te.