Formation of Self-Complementary Halogen-Bonded Dimers

Abstract

The X-ray structure of a series of iodo-and bromo-phenylethynylpyridines designed to form self-complementary dimers in the solid state are reported. The perfluoroiodo-and perfluorobromophenylethynyl derivatives, 3-[(2-bromo-3,4,5,6tetrafluorophenyl)ethynyl]pyridine, 3-[(2,3,4,5-tetrafluoro-6-iodophenyl)ethynyl]pyridine, 2-[(3-bromo-2,4,5,6-tetrafluorophenyl)ethynyl]pyridine, and 2-[(2,4,6-trifluoro-3,5-diiodophenyl)ethynyl]pyridine, formed self-complementary halogen-bonded dimeric units in the solid state. In contrast, 3-[(2-bromo-4,5-difluorophenyl)ethynyl]pyridine formed a C−H•••N hydrogenbonded dimer.

pH controlled assembly of a self-complementary halogen-bonded dimer

“…We have become interested in applying our experience 14 with self-complementary replicating templates to the creation of stable halogen-bonded assemblies in solution. Although halogen bond-based dimeric designs have been reported 15 previously in the solid state, the formation of such constructs in solution remains elusive. Recently, we have demonstrated 16 that a molecular scaffold incorporating a 5-iodo-1,4-diaryl-1 H -1,2,3-triazole XB donor and a 3-oxypyridine XB acceptor and a 5-iodo-1,4-diaryl-1 H -1,2,3-triazole XB donor can drive the formation of a halogen-bonded dimer in solution.…”

A new tecton with parallel halogen-bond donors: a path to supramolecular rectangles

“…Most of the currently available options are only capable of forming a single halogen bond (Politzer et al, 1985;Hagelin et al, 1995 the different members of the perfluorinated iodobenzene family, present their donor sites in such a way that any supramolecular assembly is likely to proceed in a divergent manner (Dahl, 1999;Padgett et al, 2005;Webb et al, 2002;Langton et al, 2014;Taylor, 2014;Jungbauer et al, 2014;Sarwar et al, 2010). There are a few reports of molecules capable of parallel multipoint halogen-bond formation but they tend to be self-complementary in nature (Oburn et al, 2015;Kirchner et al, 2015;Cao et al, 2014). Consequently, new tectons (Simard et al, 1991;Hosseini, 2005) that carry two XBdonor sites displayed in a parallel manner are highly sought after.…”

Conformational control through co-operative nonconventional C—H...N hydrogen bonds

“…We previously reported on the dominant role of the sp 2 -C-HÁ Á ÁN hydrogen bond in the crystallization of a series of (polyfluoro)phenylethynyl pyridines, as well as the cocrystallization of a series of bipyridyls with octafluorobiphenyl (Bosch et al, 2015). Those studies were initiated by the observation of selfcomplementary sp 2 -C-HÁ Á ÁN hydrogen-bonded dimer formation (Oburn et al, 2015). Others have also reported nonconventional C-HÁ Á ÁN hydrogen bonds to polyfluorophenyl-containing molecules (Prä sang et al, 2013).…”