Isomorphous crystal structures of chlorodi-acetyl-ene and iododi-acetyl-ene derivatives: simultaneous hydrogen and halogen bonds on carbon-yl

Acta Crystallogr E Crystallogr Commun. 2017 Jul 17;73(Pt 8):1175-1179. doi: 10.1107/S2056989017010155. eCollection 2017 Jul 1.


The crystal structures of tert-butyl (5-chloro-penta-2,4-diyn-1-yl)carbamate, C10H12ClNO2 (II), and tert-butyl (5-iodo-penta-2,4-diyn-1-yl)carbamate, C10H12INO2 (IV), are isomorphous to previously reported structures and accordingly their mol-ecular and supra-molecular structures are similar. In the crystals of (II) and (IV), mol-ecules are linked into very similar two-dimensional wall organizations with anti-parallel carbamate groups involved in a combination of hydrogen and halogen bonds (bifurcated N-H⋯O=C and C≡C-X⋯O=C inter-actions on the same carbonyl group). There is no long-range parallel stacking of diynes, so the topochemical polymerization of di-acetyl-ene is prevented. A Cambridge Structural Database search revealed that C≡C-X⋯O=C contacts shorter than the sum of the van der Waals radii are scarce (only one structure for the C≡C-Cl⋯O=C inter-action and 13 structures for the similar C≡C-I⋯O=C inter-action).

Keywords: chlorodi­acetyl­ene; crystal structure; halogen bond; hydrogen bond; iododi­acetyl­ene.

Grant support

This work was funded by Fonds de Recherche du Québec - Nature et Technologies grant 2016-CO-194882. Centre d’étude et de recherche transdisciplinaire étudiants-enseignants (CERTEE, Cégep de Sherbrooke) grant . Fondation du Cégep de Sherbrooke grant .