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Updated: Aug 18, 2026

Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Structure of cyclo(-L-prolylglycyl-)2 trihydrate
G Shoham1, S K Burley, W N Lipscomb
1Department of Inorganic and Analytical Chemistry, Hebrew University of Jerusalem, Israel.
Abstract:
(C14H20N4O4)2.3H2O, Mr = 670.721, monoclinic, P2(1), a = 7.353 (2), b = 21.921 (7), c = 9.878 (2) A, beta = 96.77 (2) degrees, V = 1581.1 (1) A3, Z = 2, Dx = 1.409 g cm-3, lambda(Cu Kalpha) = 1.54178 A, mu = 8.22 cm-1, F(000) = 716, T = 293 K, R = 0.034 for 2456 unique observed reflections. The two independent copies of the tetrapeptide found in the asymmetric unit have similar structures, which are both consistent with the results of NMR studies of cyclo-(-L-Pro-Gly-)2 in solution. The structures are asymmetric and have a trans-cis-trans-cis peptide backbone, in which the two L-Pro-Gly peptide bonds are trans and the two Gly-L-Pro peptide bonds are cis. A detailed comparison with other cyclic tetrapeptides is given, and a brief comparison with the results of single-crystal X-ray structures of other cyclic oligopeptides containing L-proline alternating with glycine is presented.
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