Dihydrogen contacts in alkanes are subtle but not faint

Jorge Echeverría, Gabriel Aullón, David Danovich, Sason Shaik*, Santiago Alvarez

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

233 Scopus citations

Abstract

Alkane molecules are held together in the crystal state by purportedly weak homonuclear R-H⋯H-R dihydrogen interactions. In an apparent contradiction, the high melting points and vaporization enthalpies of polyhedranes in condensed phases require quite strong intermolecular interactions. Two questions arise: 'How strong can a weak C-H⋯H-C bond be?' and 'How do the size and topology of the carbon skeleton affect these bonding interactions?' A systematic computational study of intermolecular interactions in dimers of n-alkanes and polyhedranes, such as tetrahedrane, cubane, octahedrane or dodecahedrane, showed that attractive C-H⋯H-C interactions are stronger than usually thought. We identified factors that account for the strength of these interactions, including the tertiary nature of the carbon atoms and their low pyramidality. An alkane with a bowl shape was designed in the search for stronger dihydrogen intermolecular bonding, and a dissociation energy as high as 12 kJ mol-1 is predicted by our calculations.

Original languageEnglish
Pages (from-to)323-330
Number of pages8
JournalNature Chemistry
Volume3
Issue number4
DOIs
StatePublished - Apr 2011

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