Authors: Cabezas, Carlos; Peña, Isabel; Caminati, Walther
Journal: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
Publication date: 2021/02/11
Abstract: Non-covalent interactions determine the three-dimensional structure and activity of biological molecules. In this work, the pyrrole-pyridine complex considered as a model of the N-H center dot center dot center dot N hydrogen-bonded Watson-Crick base pairs has been generated in a supersonic expansion and characterized by chirped pulse Fourier transform microwave spectroscopy. The analysis of the unconventional spectral pattern of the 1:1 pyrrole-pyridine adduct and its C-13 and N-15 isotopologues reveal a non-planar complex, with a bent N-H center dot center dot center dot N hydrogen bond and large amplitude motion of the pyrrole subunit. The bent structure is likely to arise from the stablishment of the secondary C-H center dot center dot center dot N interaction between pyridine and pyrrole moieties. (C) 2020 Elsevier B.V. All rights reserved.