Chalcogen bond

[1][2] Electrostatic, charge-transfer (CT) and dispersion terms have been identified as contributing to this type of interaction.

ChBs, much like hydrogen and halogen bonds, have been invoked in various non-covalent interactions, such as protein folding, crystal engineering, self-assembly, catalysis, transport, sensing, templation, and drug design.

[5] Given the dual ability of chalcogens to serve as donor and acceptor molecules for σ-hole interactions, a geometric schematic has been generated to distinguish between the differing bonding character.

Non-covalent interactions are well characterized by Bader's atoms in molecules (AIM) model which defines a bond as any bond-critical point (BCP) existing between two nuclei.

This has been done on a series of molecules featuring a chalcogen-chalcogen intramolecular bond in one conformation (closed) and exposed to solvent interactions in another (open).

One such study found that the preference for the closed conformation showed almost no dependence on the solvent environment.

A wide range of applications have been proposed for designing chalcogen bonds into systems where weak interactions are crucial.

This can include areas dependent on specific recognition or molecules, sort of a lock and key model, as seen in drug design, sensing, and highly selective catalysis.

Additional applications are in solid-state and materials science where particular packing of molecules can dramatically impact bulk properties.

However, clear conformational preferences have been shown in drug molecules which are attributed to the stabilization from chalcogen bonding interactions.

Examples include an asymmetric acyl transfer on an enantiomeric mixture catalyzed by a chiral isothiourea.

The acyl group is first transfer on to the chiral catalyst which is purported to go through a transition state featuring a 1,5 chalcogen bonding interaction on the catalyst which orients the acyl group prior to transfer on to the substrate.