Abstract
As a small molecule possessing both strong H-bond donor and acceptor functions, 1H-imidazole can participate in extensive homo- or heteromolecular H-bonding networks. These properties are important in Nature, as imidazole moieties are incorporated in many biologically-relevant compounds. Imidazole also finds applications ranging from corrosion inhibition to fire retardants and photography. We have found a peculiar behaviour of imidazole during scanning tunnelling microscopy-break junction (STM-BJ) experiments, in which oligomeric chains connect the two electrodes and allow efficient charge transport. We attributed this behaviour to the formation of hydrogen-bonding networks, as no evidence of such behaviour was found in 1-methylimidazole (incapable of participating in intramolecular hydrogen bonding). The results are supported by DFT calculations, which confirmed our hypothesis. These findings pave the road to the use of hydrogen-bonding networks for the fabrication of dynamic junctions based on supramolecular interactions.
Highlights
As a small molecule possessing both strong H-bond donor and acceptor functions, 1H-imidazole can participate in extensive homo- or heteromolecular H-bonding networks
As methods for single molecule electrical characterisation have advanced so have the complexity of molecular systems which can be studied
Imidazolic compounds form a range of complexes with alkali and transition metal cations, via interactions of the lone pair electrons on the imine nitrogen
Summary
As a small molecule possessing both strong H-bond donor and acceptor functions, 1H-imidazole can participate in extensive homo- or heteromolecular H-bonding networks. The complexing properties of imidazolic compounds are further evidenced by their ability to adsorb at transition metal surfaces and passivate them This phenomenon is exploited in their wide use as corrosion inhibitors. Tri- and tetrameric fragments are formed, which are bound together with the substrate.[21] Raman spectroscopy suggests the adsorption proceeds mainly through interactions of the sp[2] N atom with the metal surface, coordinated through its lone electron pair, with the ring perpendicular (or at a small tilt angle) to the surface.[22] a parallel deprotonation mechanism, with formation of imidazolate–metal bonds, is evident in in situ infrared spectroscopy.[23] Recently, it has been successfully used as a molecular contact in scanning tunnelling microscopy break junction (STM-BJ) studies, as an aurophilic terminus.[24]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call