Table of Contents
Journal of Crystallography
Volume 2014, Article ID 371629, 5 pages
http://dx.doi.org/10.1155/2014/371629
Research Article

Hydrogen Bonds between Acidic Protons from Alkynes (C–H···O) and Amides (N–H···O) and Carbonyl Oxygen Atoms as Acceptor Partners

1Département de Chimie, Cégep de Sherbrooke, 475 Rue du Cégep, Sherbrooke, QC, Canada J1E 4K1
2Laboratoire de Synthèse Supramoléculaire, Département de Chimie, Institut de Pharmacologie, Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4

Received 10 September 2013; Revised 21 November 2013; Accepted 10 December 2013; Published 12 January 2014

Academic Editor: Leonard MacGillivray

Copyright © 2014 Pierre Baillargeon et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Crystals of tert-butyl (2S)-2-(prop-2-yn-1-ylcarbamoyl)pyrrolidine-1-carboxylate (Boc-L-Pro-NHCH2CCH) have been obtained. The title compound crystallizes easily as sharp needles in orthorhombic system, space group P 21 21 21 with a = 9.2890(2), b = 9.7292(2), c = 15.7918(4) Å, V = 1427.18(6) Å3, and Z = 4. The main feature of the structure is the orientation of the carbamate and amide. Their dipoles add up and the molecule displays an electric dipole moment of 5.61 D from B3LYP/6-31G(d) calculations. The antiparallel H bonding of amides and the alignment of dipoles induce columnar stacking (the dipole moment along the columnar a axis is 4.46 D for each molecule). The other components across the other axes are, therefore weaker, (3.17 D and 1.23 D along the b and c axes, resp.). The resulting anisotropic columns pack side by side, in an antiparallel fashion mostly by (alkyne) CH···O=C (carbamate) interactions.