Weak yet directional: supramolecular interactions of thiols unravelled by quantum crystallography.

Despite being a ubiquitous functional group with biological significance, thiols remain underexplored for their ability to form intermolecular interactions - especially in the solid state. This knowledge gap is largely due to the inadequacy of conventional X-ray crystallography in accurately locating protons involved in such weak thiol hydrogen bonds. Here, we explore weak thiol hydrogen bonds, using X-ray quantum crystallography (QCr) in a series of 31 thiol crystal structures.

Dynamic Covalent Bonds in the Ebselen Class of Antioxidants Probed by X-ray Quantum Crystallography.

Dynamic bonds are essential structural ingredients of dynamic covalent chemistry that involve reversible cleavage and formation of bonds. Herein, we explore the electronic characteristics of Se-N bonds in the organo-selenium antioxidant ebselen and its derivatives for their propensity to function as dynamic covalent bonds by employing high-resolution X-ray quantum crystallography and complementary computational studies. An analysis of the experimentally reconstructed X-ray wavefunctions reveals the salient electronic features of the Se-N bonds with very low electron density localized at the bonding region and a positive Laplacian value at the bond critical point.