Double π-hole tetrel-chalcogen interactions can lead to stable molecular heterodimer

ABSTRACT

A thorough topological investigation is used to study the possible isomers of (SO₃)(H₂XY) complexes, for X=C, Si and Y=O, S. From the topological properties of the isolated monomers, up to five types of isomers can be considered, depending on the nature of the X and Y atoms. After geometry optimisations, three isomers belonging to four different types of geometry were obtained. The natures of the X and Y atoms not only affect the relative stability of the isomers, but also the interaction sites available on the H₂XY molecule. For all the systems considered in this study, a covalent structure was obtained from a non-covalent isomeric form involving a double π-hole interaction. Such a covalent structure corresponds to the global minimum for the (SO₃)(H₂CS), (SO₃)(H₂SiO) and (SO₃)(H₂SiS) complexes, and a local minimum for the (SO₃)(H₂CO) complex. The usefulness of physically-relevant topological tools for a thorough characterisation of the monomers prior to a search for the isomeric forms of a complex is once again demonstrated.

GRAPHICAL ABSTRACT

KEYWORDS:

• Electrostatic interactions
• double π-hole interactions
• QTAIM
• electron-rich and electron-depleted sites
• tetrel bonding
• chalcogen bonding

Acknowledgements

Dedicated to Prof. Andreas Savin, a friend and a scientist who thinks quickly and concludes slowly!

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental data

Supplemental data for this article can be accessed at: http://dx.doi.org/10.1080/00268976.2015.1118570.