Melting of Hydrogen Bonds in Uracil Derivatives Probed by Infrared Spectroscopy and ab Initio Molecular Dynamics
mediaposted on 19.04.2012, 00:00 by Zsolt Szekrényes, Katalin Kamarás, György Tarczay, Anna Llanes-Pallás, Tomas Marangoni, Maurizio Prato, Davide Bonifazi, Jonas Björk, Felix Hanke, Mats Persson
The thermal response of hydrogen bonds is a crucial aspect in the self-assembly of molecular nanostructures. To gain a detailed understanding of their response, we investigated infrared spectra of monomers and hydrogen-bonded dimers of two uracil-derivative molecules, supported by density functional theory calculations. Matrix isolation spectra of monomers, temperature dependence in the solid state, and ab initio molecular dynamics calculations give a comprehensive picture about the dimer structure and dynamics of such systems as well as a proper assignment of hydrogen-bond affected bands. The evolution of the hydrogen bond melting is followed by calculating the CO···H–N distance distributions at different temperatures. The result of this calculation yields excellent agreement with the H-bond melting temperature observed by experiment.