Crystal engineering in the gem-alkynol family; synthon repetitivity and topological similarity in diphenylethynylmethanols : structures that lack O-H...O hydrogen bonds

• Published in: Acta crystallographica. Section B, Structural science Structural science, 2000-12, Vol.56 (6), p.1071-1079
• Main Authors: BILTON, Clair, HOWARD, Judith A. K, MADHAVI, N. N. L, NANGIA, Ashwini, DESIRAJU, Gautam R, ALLEN, Frank H, WILSON, Chick C
• Format: Article
• Language: English
• Subjects: Aliphatic, non-condensed and condensed benzenic, and alicyclic compounds; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Organic compounds; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 0108-7681; 1600-5740
• DOI: 10.1107/S010876810001154X

The structures of four para-substituted derivatives of diphenylethynylmethanol have been determined [ditolylethynylmethanol, di(4-chlorophenyl)ethynylmethanol, di(4-bromophenyl)ethynylmethanol and bis(4,4'-biphenylyl)ethynylmethanol]. The dimethyl, dichloro, dibromo and diphenyl compounds have been analysed using X-ray diffraction at 150 K, and the dichloro compound has also been studied using neutron diffraction at 150 K. In common with the parent diphenylethynylmethanol [Garcia, Ramos, Rodriguez & Fronczek (1995). Acta Cryst. C51, 2674-2676], all four derivatives fail to form the expected strong O-H.O hydrogen bonds due to steric hindrance. Instead, the supramolecular structural organization in this family of gem-alkynols is mediated by a variety of weaker interactions. The two most acidic protons, O-H and C[triple-bond]C-H, participate in weak hydrogen bonds to pi-acceptors, forming synthons that stabilize all five structures. These primary interactions are reinforced by a variety of other weak hydrogen bonds involving C-H donors and the hydroxy-O as an acceptor, and by halogen.halogen interactions in the dichloro and dibromo compounds.