Tautomeric and ionisation forms of dopamine and tyramine in the solid state

Cruickshank, Laura and Kennedy, Alan and Shankland, Norman (2013) Tautomeric and ionisation forms of dopamine and tyramine in the solid state. Journal of Molecular Structure, 1051. pp. 132-136. ISSN 0022-2860

Full text not available in this repository.Request a copy from the Strathclyde author

Abstract

Crystallisation of the phenylethylamine neurotransmitter dopamine from basic aqueous solution yielded the 3-phenoxide Zwitterionic tautomer, despite this being a minority form in the solution state. In the crystal structure, dopamine has a dimeric [OCCOH]2 hydrogen bonded catechol motif that expands through Nsingle bondH⋯O interactions to give a 2-dimensional sheet of classical hydrogen bonds. These sheets are further interconnected by Nsingle bondH⋯π interactions. The structurally related base tyramine crystallises under similar conditions as a hemihydrate with all four possible species of tyramine present (cationic, anionic, Zwitterionic and neutral) in the crystal structure. Single crystal X-ray diffraction studies at 121 and 293 K showed dynamic hydrogen atom disorder for the phenol/phenoxide group, suggesting that the tyramine speciation observed arises from a solid-state process