Cocrystals of 1,4-diethynyl-benzene with 1,3-di-acetyl-benzene and benzene-1,4-dicarbaldehyde exhibiting strong nonconventional alkyne-carbonyl C - H⋯O hydrogen bonds between the components


Weak inter-actions between organic mol-ecules are important in solid-state structures where the sum of the weaker inter-actions support the overall three-dimensional crystal structure. The sp-C - H⋯N hydrogen-bonding inter-action is strong enough to promote the deliberate cocrystallization of a series of diynes with a series of di-pyridines. It is also possible that a similar series of cocrystals could be formed between molecules containing a terminal alkyne and molecules which contain carbonyl O atoms as the potential hydrogen-bond acceptor. I now report the crystal structure of two cocrystals that support this hypothesis. The 1:1 cocrystal of 1,4-diethynyl-benzene with 1,3-di-acetyl-benzene, C10H6·C10H10O2, (1), and the 1:1 cocrystal of 1,4-diethynyl-benzene with benzene-1,4-dicarbaldehyde, C10H6·C8H6O2, (2), are presented. In both cocrystals, a strong nonconventional ethyn-yl-carbonyl sp-C - H⋯O hydrogen bond is observed between the components. In cocrystal (1), the C - H⋯O hydrogen-bond angle is 171.8 (16)° and the H⋯O and C⋯O hydrogen-bond distances are 2.200 (19) and 3.139 (2) Å, respectively. In cocrystal (2), the C - H⋯O hydrogen-bond angle is 172.5 (16)° and the H⋯O and C⋯O hydrogen-bond distances are 2.25 (2) and 3.203 (2) Å, respectively.


Chemistry and Biochemistry

Document Type





1, 3-di-acetyl-benzene, 1, 4-diethynyl-benzene, alkyne C - H⋯O hydrogen bonds, benzene-1, 4-dicarbaldehyde, cocrystals, crystal structure, nonconventional hydrogen bonds

Publication Date


Journal Title

Acta Crystallographica Section C: Structural Chemistry