Crystal structure of l-leucyl-l-isoleucine 2,2,2-tri-fluoro-ethanol monosolvate.
Hydro-phobic dipeptides with either l-Leu or l-Phe constitute a rather heterogeneous group of crystal structures. Some form materials with large water-filled channels, but there is also a pronounced tendency to incorporate organic solvent mol-ecules, which then act as acceptors for one of the three H atoms of the charged N-terminal amino group. l-Leu-l-Ile has uniquely been obtained as two distinct hydrates, but has so far failed to co-crystallize with a simple alcohol. The present structure of C12H24N2O3·CF3CH2OH, which crystallizes with two dipeptide and two solvent mol-ecules in the asymmetric unit, demonstrates that when 2,2,2-tri-fluoro-ethanol is used as a solvent, its high capacity as a hydrogen-bond donor leads to formation of an alcohol solvate.
Department of Chemistry, University of Oslo, PO Box 1033 Blindern, N-0315 Oslo, Norway.
Carl Henrik
CH
Görbitz
crystal structure; dipeptide; head-to-tail chains; hydrogen bonds; layered structure