title: N-H...pi interactions in pyrroles: systematic trends from the vibrational spectroscopy of clusters.
abstract: Pyrrole and some of its methylated derivatives are aggregated in a controlled way in pulsed supersonic jet expansions. The cluster N-H stretching dynamics is studied using FTIR and Raman spectroscopy. Dimers, trimers and tetramers can be differentiated. Systematic trends in the dimer N-H...pi interaction as a function of methyl substitution are identified and explored for predictions. Overtone jet absorption spectroscopy is used to extract anharmonicities for the N-H bond in different environments. The N-H anharmonicity constant increases by 10% upon dimerization. Bulk matrix shifts can be emulated by the formation of Ar-decorated clusters. The experimental results are expected to serve as benchmarks for an accurate ab initio characterization of the N-H...pi hydrogen bond.
authors.affiliation: Institut für Physikalische Chemie, Universität Göttingen, Göttingen, Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Dauster
authors.forename: Corey A
authors.initials: CA
authors.lastname: Rice
authors.forename: Philipp
authors.initials: P
authors.lastname: Zielke
authors.forename: Martin A
authors.initials: MA
authors.lastname: Suhm