Two-Dimensional Organic Brick-Wall Layers as Hosts for the Inclusion and Study of Aromatics Ensembles: Acid−Pyridine and Acid−Carbonyl Synthons for Multicomponent Materials

Abstract

The compound trimesic acid (H 3 TMA) with 2,6-bis(4-pyridylmethylene)cyclohexanone (1) was shown to form two-/three-/four-component cocrystals or salts depending on the reaction conditions. Crystals of salt were obtained when crystallized H 3 TMA and 1 from MeOH alone, whereas the crystals of neutral components were obtained when crystallized from MeOH and phenol mixture. Both the structures (salt and cocrystal) exhibited huge cavities which are occupied by the self-interpenetration of the networks. This self-interpenetration of the networks found to be eschewed in favor of guest inclusion when the crystallization reactions are conducted in the presence of suitable aromatic guest molecules such as biphenyl, naphthalene, anthracene, phenanthrene, pyrene, triphenylene, and 1,4-hydroquinone. The crystal structures of cocrystals contain hydrogen-bonded layers with huge cavities, the self-interpenetrated layers have a honeycomb geometry with the cavity dimensions of 23 Â 42 A ˚2 and the guest included layers have a brick wall geometry with cavity sizes of 8 Â 23 A ˚2. The guest occupied volume of these materials varies from 12 to 38% of crystal volume. In the four-component systems, the adducts of guest molecules were found between pyrene-phenol, pyrene-1,4-hydroquinone, and phenanthrene-o-cresol. In three-component systems, the packing of guest biphenyls is similar to that of the biphenyl crystal structure itself.

Cocrystals and Salts of 4,4′-Dinitro-2,2′,6,6′-tetracarboxybiphenyl with N-Heterocycles: Solid State Photodimerization of Criss-Cross Aligned Olefins and Photophysical Properties

“…Formation of a cocrystal or salt depends on several factors such as the Δp K a value of the acid–base system, nature of the solvents, solution concentration, and pH. − Crystal structures of cocrystals and salts are generally analyzed in terms of supramolecular synthons which are formed by hydrogen bonding or intermolecular interactions between same functional groups (homosynthon) or different functional groups (heterosynthon). − Among various synthons, acid-pyridine synthons (synthons I and II ) are well established for designing cocrystals and salts. There are several literature reports where an acid-pyridine synthon was shown to play a pivotal role in the formation of derived hydrogen-bonded networks of cocrystals or salts. − Synthon competition has been also studied thoroughly by including other functional groups in the cocrystal formers containing acid or pyridyl moiety. , Earlier, from our group, acid-pyridine and acid-carbonyl synthons, between trimesic acid and 2,6-bis­(4-pyridylmethylene)­cyclohexanone, were shown to form two-dimensional brick-wall layers which were found to act as a host system for the inclusion of a variety of aromatic guest molecules …”

“…38,39 Earlier, from our group, acid-pyridine and acidcarbonyl synthons, between trimesic acid and 2,6-bis(4pyridylmethylene)cyclohexanone, were shown to form twodimensional brick-wall layers which were found to act as a host system for the inclusion of a variety of aromatic guest molecules. 40 Crystal engineering studies unveiled the importance of templates to facilitate solid state photocycloaddition reactions. 41−44 Solid state [2 + 2] photochemical reactions have been extensively explored in cocrystals, salts, and coordination complexes/polymers.…”

Construction of Hydrogen‐Bonded Ternary Organic Crystals Derived from L‐Tartaric Acid and Their Application to Enantioseparation of Secondary Alcohols

“…[16] Because the highly symmetric and less flexible structure of 2 a is expected to be favorable for the construction of supramolecular host systems, combinations of l-tartaric acid derivatives (1 a, 1 b) and 2 a were applied to the enantioselective inclusion of various benzylic alcohols (3). The results are shown in Table 1.…”

2-({[(Pyridin-1-ium-2-ylmethyl)carbamoyl]formamido}methyl)pyridin-1-ium bis(3,5-dicarboxybenzoate): crystal structure and Hirshfeld surface analysis

“…The conformational flexibility in 3,5-dicarboxybenzoate anions is well illustrated in arguably the four most closely related structures in the crystallographic literature (Groom & Allen, 2014), identified from approximately 35 organic salts containing this anion. Referring to Scheme 2, the most closely related structure features the dication C_I with two protonated pyridyl N atoms (Santra et al, 2009). Here, with two crystallographically independent anions, twists are noted from the mean-plane data collated in Table 3.…”