Crystal structure of 4,4'-bipyridine 3-(sulfonyl-glycine)benzoic acid (1:1), C10H8N2 · C6H5O6S

Abstract

Source of material 4,4-bipyridine (0.09 g, 0.5 mmol), 3-(sulfonyl-glycine)benzoic acid (0.11 g, 0.5 mmol), and NaOH (0.02 g, 0.5 mmol) were added to water (12 ml) in a Teflon-lined stainless steel reactor. DiscussionThe rational design via self-assembly driven by coordination and/or hydrogen-bonded force has been proven to be an effective and facile synthetic strategy. Beside from the fundamental and strong metal-ligand coordination driven force, other relatively weak intermolecular interactions such as hydrogen bonding and aromatic stacking are also useful tools in construction of the crystalline materials, and a variety of infinitely extended networks have been generated via interplay of these valid interactions [1][2][3][4][5][6][7][8][9][10]. Using a building block methodology, a number of discrete and a wide range of infinite solid-state coordination frameworks have already been generated with simple organic spacers, such as 4,4-bipyridine. Except for covalent inter-actions, one of the best strategies to design high-dimensional supramolecular systems is to utilize the hydrogen bonding of the bridging ligand in addition to their coordination capability. Of particular interest are compounds that are capable of forming very strong hydrogen bonds like some salts of poly acid. The 3-(sulfonylglycine)benzoic acid, also known as pyromellitic acid, possesses several interesting characteristics: (a) it has two carboxyl groups which may be completely or partially deprotonated, inducing rich coordination modes and allowing interesting structures with higher dimensions; (b) it can act not only as hydrogen-bond acceptor but also as hydrogen-bond donor, depending upon the numbers of deprotonated carboxyl groups. The crystal structure of the title compound comprises a 4,4-bipyridine molecule and a 3-(sulfonyl-glycine)benzoic acid molecule per asymmetric unit ( figure, top). Both of the carboxylate groups of the acid are protonated. Hydrogen bonding and intermolecular weak interactions play an important role in the structure of the title compound ( figure, bottom). A short intermolecular distance between N2 and O1 atoms of 2.616 Å is found, corresponding to an intermolecular hydrogen bond. Another kind of hydrogen bonding is present: hydrogen bonding between the carboxylate oxygen atoms from adjacent molecules with an O···O distance of 2.628 Å. Then, an extended one-dimensional network structure along [101] is formed in which N···O hydrogen bonding and eight-membered ring units are alternately arranged.

Aromatic versus Aliphatic Carboxyl Group as a Hydrogen Bond Donor in Salts and Cocrystals of an Asymmetric Diacid and Pyridine Derivatives

“…In order to attempt answering this question, we have decided to study a series of cocrystals and salts formed from pyridine derivatives and an asymmetric aliphatic-aromatic carboxylic diacid. While pyridine derivatives and carboxylic acids are very common building blocks in solid state supramolecular chemistry, to the best of our knowledge only seven structures which contain asymmetric diacids in combination with pyridine derivatives have been deposited with the CSD to date. − We have therefore decided to synthesize a simple asymmetric aliphatic–aromatic carboxylic diacid and cocrystallize it with a series of pyridine derivatives in order to observe which carboxyl group (if any) is the preferred hydrogen donor, and how this correlates with p K a values and electrostatic potentials of the carboxyl groups. For the model diacid we have chosen cindroic acid ( N -(2-carboxyphenyl)­glycine, H 2 cin ; Scheme ), a precursor of indigo in the classical Heumann synthesisthe first commercially affordable route to synthetic indigo .…”