Different carboxylic acid homodimers in self-assemblies of adducts of 3-carboxyphenoxyacetic acid with nitrogen containing compounds

Shankar, Krapa; Baruah, Jubaraj B.

doi:10.1007/s12039-016-1071-7

Cited by 4 publications

(5 citation statements)

References 62 publications

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“…Caffeine is a heterocyclic compound that has distinction to have different hydrogen bonded units across dicarboxylic acid . The caffeine has also certain similar supramolecular feature as that of quinazolin‐4(3H)‐one which forms cocrystal with 5‐aminoisophthalic acid .…”

Section: Resultsmentioning

confidence: 99%

“…[20][21][22][23][24] Some unsymmetrical dicarboxylic acids undergo preferential deprotonation [31] and certain acids form monodeprotonated salt. [32] A zwitterion has different complementarity for hydrogen bond than the conventional neutral form the changes in the hydrogen bonding patterns due to change in the ability to interact differently. The 5-aminoisophthalic acid is a commercially available amino-dicarboxylic acid that exists as zwitterion.…”

Section: Introductionmentioning

confidence: 99%

“…Caffeine is a heterocyclic compound that has distinction to have different hydrogen bonded units across dicarboxylic acid. [32] The caffeine has also certain similar supramolecular feature as that of quinazolin-4(3H)-one which forms cocrystal with 5-aminoisophthalic acid. [33] So we studied the crystal structure of 1: 1 cocrystal of H 4 isop with caffeine ( Figure 4a) to evaluate the possibility of an unsymmetrical bridging by caffeine to hold two molecules of 5-aminoisophthalic acid.…”

Section: Introductionmentioning

confidence: 99%

“…A mono‐deprotonated dicarboxylic acid also may form cocrystal (B−H) + (B)(AH) − (Where B is a nitrogen based compound and AH is mono‐anion of a dicarboxylic acid) . Some unsymmetrical dicarboxylic acids undergo preferential deprotonation and certain acids form mono‐deprotonated salt . A zwitterion has different complementarity for hydrogen bond than the conventional neutral form the changes in the hydrogen bonding patterns due to change in the ability to interact differently.…”

Section: Introductionmentioning

confidence: 99%

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Neutral, Zwitterion, Ionic Forms of 5‐Aminoisophthalic Acid in Cocrystals, Salts and Their Optical Properties

2019

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Different ionic and zwitterionic forms of amphoteric 5‐aminoisophthalic acid were observed in the self‐assemblies of five salts and in a cocrystal. The presence of these forms of the molecule caused differences in respective local environments, which were reflected in corresponding absorption and emission spectra in solid state. Dianion of the acid was observed in hydrated 1:2 salt with 6‐methylpyridin‐2‐amine whereas the salt of 5‐methylthiazol‐2‐amine had the zwitterionic anion. The mono‐anion of the 5‐aminoisophthalic acid was observed in the salt of 4,6‐dimethylpyrimidin‐2‐amine. The self‐assembly of the 1:1 cocrystal of caffeine with 5‐aminoisophthalic acid had neutral form of the acid and the cationic form of the acid was observed in the perchlorate and bromide salts. DFT‐calculation with using CAMB3LYP functional with 6–31+G (d,p) as basis set in gas‐phase showed that different HOMO‐LUMO gaps of the neutral, cation and anion forms and these were reflected in the corresponding UV‐visible spectra of the salt. The changes in intra‐molecular charge transfer (ICT) fluorescence emissions in solid samples due to the different ionic forms were demonstrated.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Neutral, Zwitterion, Ionic Forms of 5‐Aminoisophthalic Acid in Cocrystals, Salts and Their Optical Properties

2019

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“…Such examples are oen observed in closed-packed structures having a high p-stacking environment. [57][58][59] The 2,7-dihydroxynaphthalene cocrystal had a 2.5 : 1 molar ratio. In this example, two hydroxy groups of each 2,7-dihydroxynaphthalene could hold two independent phenazine molecules through O1-H/N4 and O2-H/N2 hydrogen bonds (Table S1 †), forming a clip-like structure (Fig.…”

Section: Resultsmentioning

confidence: 99%

Stacking among the clips of the poly-aromatic rings of phenazine with hydroxy-aromatics and photophysical properties

2019

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Clip-like arrangements of molecules in the cocrystals of phenazine with hydroxy-aromatics in their respective self-assemblies and photophysical properties were presented. Phenazine cocrystals with 1,2dihydroxybenzene provided assembly with butterfly-like arrangements. In these cocrystals, the phenazine molecules occurred in parallel pairs having extensive p-stacking. The clip-like cocrystals with 1,3-dihydroxybenzene also exhibited parallel pairs of phenazine molecules that were parallel cofacial pstacked. The hydrated cocrystals of phenazine with 1,2,3-trihydroxybenzene had chains of parallel cofacial phenazine rings having three distinguishable p-separation distances among the centroids of the phenazine rings. Also, 2,7-dihydroxynaphthalene formed a clip-like cocrystal with phenazine, which encapsulated an additional molecule of phenazine. This cocrystal also provided chain-like parallel arrangements of the phenazine molecules. The emission and quantum yields of the cocrystals were determined by the integrating sphere method, which indicated that only the cocrystal of phenazine with 2,7-dihydroxynaphthalene showed monomer-like emission of phenazine and the rest of the cocrystals were in a quenched state. In the solution phase, quenching of the emission of hydroxynaphthalene was observed when phenazine was added to an independent solution of 2,7-dihydroxynaphthalene or another hydroxynaphthalene. However, when hydroxybenzenes were added to a solution of phenazine, fluorescence enhancements of phenazine occurred due to photo-electron transfer. Fig. 1 (a) Some possible hydrogen-bonded assemblies of phenazine with aromatic diols and (b) structures of phenazine and different organic aromatic diols used in this study.33404 | RSC Adv., 2019,9,[33403][33404][33405][33406][33407][33408][33409][33410][33411][33412] This journal is

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Conformational adjustments over synthons of urea and thiourea based assemblies

Phukan

Baruah

2016

CrystEngComm

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Conformational adjustments in 1-(n-methylthiazol-2-yl)-3-naphthalen-1-yl-thiourea (n = 4, 5) through carbon-nitrogen bond rotation over an intramolecular hydrogen bonded synthon were established. Isosteric homodimeric hydrogen bonded synthons were analysed in their respective self-assemblies. The corresponding urea derivatives, namely, 1-(n-methylthiazol-2-yl)-3-naphthalen-1-yl-urea (n = 4, 5) also had similar homodimeric sub-assemblies in each of their respective assemblies. However, these two positional isomers of a urea derivative did not show polymorphism, which was observed in the corresponding thiourea counterpart. On the other hand, 1-(5-methylthiazol-2-yl)-3-naphthalen-1-yl-thiourea underwent a facile cyclisation reaction, whereas 1-(5-methylthiazol-2-yl)-3-naphthalen-1-yl-urea formed hydrated salts upon reaction with different inorganic acids. Self-assembly of chloride salt had a bifurcated hydrogen bond between two N-H of the urea moiety with chloride ion, whereas perchlorate salt had a similar bond with the oxygen atom of a water of crystallization, making a difference in the type of heterosynthon. Thus, heterosynthons of these salts were found to be anion dependent. Each salt has a cation differing in conformational adjustments guided by anions. Multi-component hydrated and anhydrous crystals of 1-(5-methylthiazol-2-yl)-3-naphthalen-1-yl-urea with tetrabutylammonium chloride were formed concomitantly. These are examples of anion-guided assemblies of thiazole based compounds containing a neutral host. The different naphthyl group orientations of the heterosynthon resulted in two polymorphic hydrated cocrystals.

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Different carboxylic acid homodimers in self-assemblies of adducts of 3-carboxyphenoxyacetic acid with nitrogen containing compounds

Cited by 4 publications

References 62 publications

Neutral, Zwitterion, Ionic Forms of 5‐Aminoisophthalic Acid in Cocrystals, Salts and Their Optical Properties

Neutral, Zwitterion, Ionic Forms of 5‐Aminoisophthalic Acid in Cocrystals, Salts and Their Optical Properties

Stacking among the clips of the poly-aromatic rings of phenazine with hydroxy-aromatics and photophysical properties

Conformational adjustments over synthons of urea and thiourea based assemblies

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