Related Experiment Video
Updated: May 11, 2026
Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
The versatile role of the ethynyl group in crystal packing: an interaction propensity study
Frank H Allen1, Peter A Wood, Peter T A Galek
1Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, England. allen@ccdc.cam.ac.uk
Abstract:
It is well documented that the ethynyl group can act as a hydrogen-bond donor via its acidic C-H, and as a hydrogen-bond acceptor via the triple-bond π-density. Using the Cambridge Structural Database (CSD), it is shown that C-C≡C-H forms hydrogen bonds to N, O, S or halogens in 74% of structures in which these bonds can form. Additionally, the ethynyl group forms C-H···π interactions with itself or with phenyl groups in 23% of structures and accepts hydrogen bonds from O-H, N-H or C(aromatic)-H in 47% of structures where such bonds are possible. Overall, C-C≡C-H acts as a donor or acceptor in 87% of structures in which it occurs. These propensities for hydrogen-bond formation have been determined using quite tight geometrical constraints, and many more ethynyl groups form interactions with only slight relaxations of these constraints. We conclude that the ethynyl group makes crucial contributions to molecular aggregation in crystal structures, and this is exemplified by hydrogen-bond predictions for specific structures made using the statistical propensity tool now available in CSD system software.
More Related Videos
10:33Development of Inhibitors of Protein-protein Interactions through REPLACE: Application to the Design and Development Non-ATP Competitive CDK Inhibitors
Published on: October 26, 2015
10:45Crystallization and Structural Determination of an Enzyme:Substrate Complex by Serial Crystallography in a Versatile Microfluidic Chip
Published on: March 20, 2021
Related Concept Videos
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
02:30Stability of Substituted Cyclohexanes
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
02:02Chair Conformation of Cyclohexane
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
03:35Hybridization of Atomic Orbitals II
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
02:33Stereoisomerism of Cyclic Compounds