Crystal engineering in the gem-alkynol family: interplay between strong and weak interactions in structures of 2,3,5,6-tetrahalo[F,Cl,Br]-trans-1,4-diethynylcyclohexa-2,5-diene-1,4-diol s

摘要

Structures of the title compounds are all mediated by strong cooperative arrangements of O-H . . .O hydrogen bonds, supported by a variety of weaker interactions which affect the type of O-H . . .O synthon that is formed. The tetrafluoro compound contains hexameric O-H . . .O synthons in a supramolecular chair conformation, together with C=C-H . . .F interactions. However, the tetrachloro and tetrabromo compounds both form tetrameric O-H . . .O synthons. This dominant pattern is supported by halogen...halogen interactions having one C-Cl[Br]. . . Cl[Br] angle close to 180 degrees and the other close to 90 degrees, and by C=C-H . . . Cl[Br] interactions. [References: 36]