London Dispersion Enables the Shortest Intermolecular Hydrocarbon H•••H Contact
Authors
- Sören Rösel
- Henrik Quanz
- Christian Logemann
- Jonathan Becker
- Estelle Mossou
- Laura Canãdillas-Delgado
- Eike Caldeweyher
- Stefan Grimme
- Peter R. Schreiner
Abstract
Neutron diffraction of tri(3,5-tert-butylphenyl)-methane at 20 K reveals an intermolecular C–H···H–C distance of only 1.566(5) Å, which is the shortest reported to date. The compound crystallizes as a C3-symmetric dimer in an unusual head-to-head fashion. Quantum chemical computations of the solid state at the HSE-3c level of theory reproduce the structure and the close contact very well (1.555 Å at 0 K) and emphasize the significance of packing effects; the gas-phase dimer structure at the same level shows a 1.634 Å C–H···H–C distance. Intermolecular London dispersion interactions between contacting tert-butyl substituents surrounding the central contact deliver the decisive energetic contributions to enable this remarkable bonding situation.