Intermolecular interactions in group 14 hydrides: Beyond CH···HC contacts

• Published in: International journal of quantum chemistry 2017-11, Vol.117 (21), p.n/a
• Main Authors: Echeverría, Jorge, Aullón, Gabriel, Alvarez, Santiago
• Format: Article
• Language: English
• Subjects: ab initio calculations; dihydrogen interactions; supramolecular chemistry
• ISSN: 0020-7608; 1097-461X
• DOI: 10.1002/qua.25432

In line with previous work in which we established the factors that enhance attractive CH···HC dihydrogen interactions in alkanes, an extended theoretical analysis of noncovalent intermolecular interactions in group 14 hydrides is presented here. Remarkably, these weak interactions may play a major role in determining the crystal structures adopted by several families of molecules. A combined structural and computational analysis at the MP2 level allowed us to identify and characterize different interactions of the type EH···HE and E···HE (E = Si, Ge, Sn, and Pb), and to find also the most suitable scenario for the establishment of each particular type. The nature of the interactions has been analyzed in terms of natural charges of the atoms involved and a topological analysis of the electron density of several dimers confirms the existence of H···H and H···E attractive contacts. We have observed that the interaction strength increases when descending down the periodic group and that silicon has a marked tendency to establish Si···HSi interactions. A size‐dependent backbone effect that reinforces H···H dihydrogen interactions in polyhedral systems has also been found. E···H (E = Si, Ge, Sn) and H···H short interactions are present in the crystal structures of many group 14 hydrides derivatives. The strength of the interaction increases when descending down the group, and is reinforced by a backbone effect that results in very large dissociation energies for dimers of polymeric molecules.