Hydrophobic dipeptides: the final piece in the puzzle

Abstract

The crystal structure of L-valyl-L-leucine aceto­nitrile solvate presented here adds to 24 previously reported structures of dipeptides constructed from the five nonpolar amino acids L-alanine, L-valine, L-isoleucine, L-leucine and L-phenyl­alanine. It thus constitutes the final piece in the 5 × 5 puzzle of hydro­phobic dipeptide structures. This opportunity is taken to review the crystal packing arrangements and hydrogen-bonding preferences of a rather unique group of substances, with updated information on the various hydrogen-bonding patterns and the associated peptide conformations.