The shape of neurotransmitters in the gas phase: A theoretical study of adrenaline, pseudoadrenaline, and hydrated adrenaline

Abstract

The conformational landscapes of adrenaline and pseudoadrenaline have been explored by electronic structure computation at the B3LYP/6-31+G*, MP2/6-31+G* and MP2/aug-cc-pVDZ levels of theory. Based on the relative energies of the different conformers, we conclude that the extended AG1a and folded GG1a conformers are the most likely candidates for detection in spectroscopy experiments using a supersonic expansion. Predictions for the infrared spectra of the AG1a and GG1a conformers and their 1∶1 hydrates are presented. We explored the suitability of a rigid-body DMA-based model potential to locate the most stable 1∶1 and 1∶2 adrenaline-water clusters. The model potential was able to locate all relevant 1∶1 clusters, but failed to find the most stable 1∶2 cluster.