New supramolecular arrays based on interactions between carboxylate and urea groups: solid-state and solution behavior

The properties of a series of organogels consisting of a urea or thiourea derivative with one or two n-alkyl substitutuents at the nitrogen atoms (a low molecular-mass organogelator (LMOG)) and an organic liquid are described. They include N,N'-dimethylurea, the LMOG of lowest molecular mass (M(W) 88) we are aware of. The efficiencies of the LMOGs, based the diversity of liquids gelated, the minimum amount required for gelation of a liquid at room temperature, and the temporal and thermal stabilities of the gels formed, have been investigated as a function of the number, length, and substitution pattern of their n-alkyl chains. The gels are thermally reversible and require generally very low concentrations (<2 wt %) of an LMOG. Some of the LMOGs with shorter chains are more efficient than their longer chained analogues. The structural and thermodynamic properties of the gels have been examined by IR, DSC, and X-ray diffraction techniques. Polarizing optical microscopic analyses of the gels show that the nature of gelator aggregates depends mainly on the alkyl chain length. Changes in the aggregation ability have been examined systematically by perturbing the molecular structure.

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“…[1,2] It is known to form inclusion complexes with n-alkanes (! 7 carbon atoms) [3][4][5][6] and some functionalized longchain molecules.…”

Section: Introductionmentioning

confidence: 99%

Urea and Thiourea Derivatives as Low Molecular‐Mass Organogelators

George

Tan

John

et al. 2005

Chemistry A European J

164

108

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“…Therefore, such molecules lie at the forefront of modern chemical research [23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

One pot synthesis of Cu(II) 2,2′-bipyridyl complexes of 5-hydroxy-hydurilic acid and alloxanic acid: Synthesis, crystal structure, chemical nuclease activity and cytotoxicity

Dixit

Koiri

Maurya

et al. 2011

Journal of Inorganic Biochemistry

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“…One of the few examples of five‐membered supramolecular macrocycles was reported in 1998 by Hamilton and co‐workers . They previously showed that acylaminopyridine and carboxylic acid derivatives could form extended or cyclic aggregates depending on the conditions and the nature of the interacting components.…”

Section: Hydrogen‐bonded Macrocycles In Solutionmentioning

confidence: 99%

Hydrogen‐Bonded Macrocyclic Supramolecular Systems in Solution and on Surfaces

2015

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Cyclization into closed assemblies is the most recurrent approach to realize the noncovalent synthesis of discrete, well‐defined nanostructures. This review article particularly focuses on the noncovalent synthesis of monocyclic hydrogen‐bonded systems that are self‐assembled from a single molecule with two binding‐sites. Taking advantage of intramolecular binding events, which are favored with respect to intermolecular binding in solution, can afford quantitative amounts of a given supramolecular species under thermodynamic control. The size of the assembly depends on geometric issues such as the monomer structure and the directionality of the binding interaction, whereas the fidelity achieved relies largely on structural preorganization, low degrees of conformational flexibility, and templating effects. Here, we discuss several examples described in the literature in which cycles of different sizes, from dimers to hexamers, are studied by diverse solution or surface characterization techniques.

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New supramolecular arrays based on interactions between carboxylate and urea groups: solid-state and solution behavior

Cited by 22 publications

References 10 publications

Urea and Thiourea Derivatives as Low Molecular‐Mass Organogelators

Urea and Thiourea Derivatives as Low Molecular‐Mass Organogelators

One pot synthesis of Cu(II) 2,2′-bipyridyl complexes of 5-hydroxy-hydurilic acid and alloxanic acid: Synthesis, crystal structure, chemical nuclease activity and cytotoxicity

Hydrogen‐Bonded Macrocyclic Supramolecular Systems in Solution and on Surfaces

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