calix(4)arene and barbituric-acid

calix(4)arene has been researched along with barbituric-acid* in 2 studies

Other Studies

2 other study(ies) available for calix(4)arene and barbituric-acid

Article	Year
Self-assembly and stability of double rosette nanostructures with biological functionalities. Organic & biomolecular chemistry, 2005, Oct-21, Volume: 3, Issue:20 The syntheses of calix[4]arene dimelamines that are functionalized with alkyl, aminoalkyl, ureido, pyridyl, carbohydrate, amino acid and peptide functionalities, and their self-assembly with barbituric acid or cyanuric acid derivatives into well-defined hydrogen-bonded nanostructures are described. The thermodynamic stability of these hydrogen-bonded assemblies was studied by CD spectroscopy in mixtures of CHCl3 and MeOH. The stability of the assemblies depends on several steric factors and the polarity of the functional groups connected to the assembly components. Topics: Amines; Amino Acids; Barbiturates; Calixarenes; Carbohydrates; Circular Dichroism; Hydrogen Bonding; Molecular Conformation; Nanostructures; Peptides; Phenols; Stereoisomerism; Thermodynamics; Triazines	2005
Amplification of chirality: the "sergeants and soldiers" principle applied to dynamic hydrogen-bonded assemblies. Journal of the American Chemical Society, 2001, Oct-24, Volume: 123, Issue:42 The amplification of supramolecular chirality has been studied in dynamic chiral hydrogen-bonded assemblies 1(3).(CA)(6) using "Sergeants and Soldiers" experiments. Previously, we have shown that chiral centers present in either the dimelamine component 1 or the cyanurate component CA quantitatively induce one handedness (M or P) in the assembly. This offers the possibility to study the amplification of chirality under two different kinetic regimes. When chiral dimelamines 1 are used, the exchange of chiral components and (M/P)-interconversion, i.e., interconversion between the (M)- and (P)-isomers of assembly 1(3).(CA)(6), take place via identical pathways (condition A). When chiral cyanurates CA are used, the exchange of chiral components occurs much faster than (M/P)-interconversion (condition B). Experimentally, a much stronger chiral amplification is observed under condition B. For example, the observed chiral amplification for a mixture of chiral and achiral components (40:60) is 46% under condition B and 32% under condition A. Kinetic models were developed to fit the experimental data and to simulate chiral amplification in dynamic systems in general. These simulations show that it is theoretically possible that the diastereomeric excess in a dynamic system is more than 99% with less than 1% chiral component present! Topics: Barbiturates; Calixarenes; Hydrogen Bonding; Kinetics; Models, Chemical; Phenols; Stereoisomerism; Thermodynamics; Triazines	2001

Article

Year

Self-assembly and stability of double rosette nanostructures with biological functionalities.

Organic & biomolecular chemistry, 2005, Oct-21, Volume: 3, Issue:20

The syntheses of calix[4]arene dimelamines that are functionalized with alkyl, aminoalkyl, ureido, pyridyl, carbohydrate, amino acid and peptide functionalities, and their self-assembly with barbituric acid or cyanuric acid derivatives into well-defined hydrogen-bonded nanostructures are described. The thermodynamic stability of these hydrogen-bonded assemblies was studied by CD spectroscopy in mixtures of CHCl3 and MeOH. The stability of the assemblies depends on several steric factors and the polarity of the functional groups connected to the assembly components.

Topics: Amines; Amino Acids; Barbiturates; Calixarenes; Carbohydrates; Circular Dichroism; Hydrogen Bonding; Molecular Conformation; Nanostructures; Peptides; Phenols; Stereoisomerism; Thermodynamics; Triazines

2005

Amplification of chirality: the "sergeants and soldiers" principle applied to dynamic hydrogen-bonded assemblies.

Journal of the American Chemical Society, 2001, Oct-24, Volume: 123, Issue:42

The amplification of supramolecular chirality has been studied in dynamic chiral hydrogen-bonded assemblies 1(3).(CA)(6) using "Sergeants and Soldiers" experiments. Previously, we have shown that chiral centers present in either the dimelamine component 1 or the cyanurate component CA quantitatively induce one handedness (M or P) in the assembly. This offers the possibility to study the amplification of chirality under two different kinetic regimes. When chiral dimelamines 1 are used, the exchange of chiral components and (M/P)-interconversion, i.e., interconversion between the (M)- and (P)-isomers of assembly 1(3).(CA)(6), take place via identical pathways (condition A). When chiral cyanurates CA are used, the exchange of chiral components occurs much faster than (M/P)-interconversion (condition B). Experimentally, a much stronger chiral amplification is observed under condition B. For example, the observed chiral amplification for a mixture of chiral and achiral components (40:60) is 46% under condition B and 32% under condition A. Kinetic models were developed to fit the experimental data and to simulate chiral amplification in dynamic systems in general. These simulations show that it is theoretically possible that the diastereomeric excess in a dynamic system is more than 99% with less than 1% chiral component present!

Topics: Barbiturates; Calixarenes; Hydrogen Bonding; Kinetics; Models, Chemical; Phenols; Stereoisomerism; Thermodynamics; Triazines

2001