Racemic 1,2-diphenylbut-3-yn-2-ol

Abstract

Molecules of the title compound, C(16)H(14)O, are chiral and crystallize in space group P-4 with Z' = 2, and with one R and one S molecule in the asymmetric unit. The conformations of the phenyl rings in the two independent molecules differ slightly. Supramolecular organization in the crystal is via tetrameric O-H. H(O) hydrogen-bonded synthons formed separately by each conformer. These tetrameric synthons stack along the c axis via C[triple-bond]C-H.O(H) hydrogen bonds. The only link between the conformer stacks is provided by weaker C(methylene)-H and C(phenyl)-H interactions with pi(arene) density.

4-Ethynyl-4-hydroxycyclohexan-1-one and 4-ethynyl-4-hydroxy-2,3,5,6-tetramethylcyclohexa-2,5-dien-1-one

“…There are no direct intermolecular interactions involving the atoms of the gem-alkynol group. These results are not unexpected as our previous analysis of 94 existing gem-alkynol structures (Madhavi, Bilton et al, 2000) retrieved from the Cambridge Structural Database (Allen & Kennard, 1993) contained 39 examples which also contained carbonyl acceptors, and in 34 of these cases, the alkynol OH group is hydrogen bonded to the carbonyl-O atom rather than to itself.…”

“…The structures of the title compounds, (I) and (II), have been determined as part of a detailed study of the intermolecular interaction patterns, or synthons (Desiraju, 1995), formed by a series of gem-alkynols in which additional substitution has been carefully controlled by novel syntheses. The aim has been to establish the synthons formed by the gem-alkynol group alone attached to hydrocarbon skeletons (Bilton et al, 1999;Madhavi, Bilton et al, 2000) and to see how the resulting patterns, arising from a delicate balance between strong and weak interactions, are either maintained or altered by controlled substitution of these skeletons by other functional groups, particularly halogens (Madhavi, Desiraju et al, 2000) and substituted phenyl rings (Bilton et al, 2000). The overall goal has been to determine the robustness of the various synthons formed so as to develop their use in crystal engineering applications.…”

“…Compounds (I) and (II) were isolated as by-products in the syntheses of 1,4-diethynylcyclohexane-1,4-diol [(III); Bilton et al, 1999] and 1,4-diethynylcyclohexa-2,5-diene-1,4-diol [(IV); Madhavi, Bilton et al, 2000], respectively. The compounds are clearly similar at the molecular level and it is of interest to see if this molecular similarity is re¯ected in similarities in their crystal structures, and also how these crystal structures relate to those of the respective bis(gem-alkynol) analogues, (III) and (IV), i.e.…”

Structural studies of 2‐methyl‐7‐substituted pyrazolo[1,5‐a]pyrimidines

“…The fluorine atom as halogen bonding has been related to noncovalent interactions, however, while, the Ar‐ArF stacking motif formed between nonfluorinated and perfluorinated aromatic rings is rated an important supramolecular synthon [26], the contacts of C‐F···H [27, 28], C‐F···F [29] and C‐F···πF [30] type are not yet sufficiently clear [31, 32]. On the other hand, the ability of the fluorine–fluorine intermolecular interactions in directing the supramolecular structure of synthons concerning atoms of aliphatic systems is unknown.…”

(4aR,8aS,9aR,10aS)-8a,9a-Difluoro-1,4,4a,5,8,8a,9,9a,10,10a-decahydroanthracene-4a,10a-diol hemihydrate

“…(Howard et al, 1996;Dunitz & Taylor, 1997;Dunitz, 2004;Reichenbaecher et al, 2005;Dunitz & Schweizer, 2006;Cozzi et al, 2007). While a large body of scientific evidence points towards organic fluorine being a weak hydrogen-bond acceptor, capable of engaging in C-FÁ Á ÁH-X (X is O, N or C) interactions (Madhavi et al, 2000;Nangia, 2000;Vangala et al, 2002;Desiraju, 2002;Mountford et al, 2003;Li et al, 2005;Bernet & Vasella, 2007;Borho & Xu, 2008;Chopra & Guru Row, 2011), other studies conclude that fluorine may not be involved in hydrogen bonding at all (Dunitz & Taylor, 1997;Dunitz, 2004;Dunitz & Schweizer, 2006;Cozzi et al, 2007). While a large body of scientific evidence points towards organic fluorine being a weak hydrogen-bond acceptor, capable of engaging in C-FÁ Á ÁH-X (X is O, N or C) interactions (Madhavi et al, 2000;Nangia, 2000;Vangala et al, 2002;Desiraju, 2002;Mountford et al, 2003;Li et al, 2005;Bernet & Vasella, 2007;Borho & Xu, 2008;Chopra & Guru Row, 2011), other studies conclude that fluorine may not be involved in hydrogen bonding at all (Dunitz & Taylor, 1997;Dunitz, 2004;Dunitz & Schweizer, 2006;Cozzi et al, 2007).…”