## Abstract

An isolated, gas-phase dimer of imidazole is generated through laser vaporisation of a solid rod containing a 1:1 mixture of imidazole and copper in the presence of an argon buffer gas undergoing supersonic expansion. The complex is characterised through broadband rotational spectroscopy and is shown to have a twisted, hydrogen-bonded geometry. Calculations at the CCSD(T)(F12∗)/cc-pVDZ-F12 level of theory confirm this to be the lowest-energy conformer of the imidazole dimer. The distance between the respective centres of mass of the imidazole monomer subunits is determined to be 5.2751(1) Å, and the twist angle γ describing rotation of one monomer with respect to the other about a line connecting the centres of mass of the monomers is determined to be 87.9(4)°. Four out of six intermolecular parameters in the model geometry are precisely determined from the experimental rotational constants and are consistent with results calculated ab initio.

Original language | English |
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Pages (from-to) | 1154-1158 |

Number of pages | 5 |

Journal | ChemPhysChem |

Volume | 17 |

Issue number | 8 |

DOIs | |

Publication status | Published - 18 Apr 2016 |

## Keywords

- ab initio calculations
- dimerization
- hydrogen bonds
- nitrogen heterocycles
- rotational spectroscopy