Search results for " ion pairs"

showing 3 items of 3 documents

Low-Q peak in X-ray patterns of choline-phenylalanine and homophenylalanine: a combined effect of chain and stacking

2016

Abstract In this contribution we report for the first time the X-ray patterns of choline-phenylalanine and choline-homophenylalanine ionic liquids. The presence of a low Q peak in both systems is another evidence that a long alkyl chain is not always needed to establish a nanodomain segregation in the liquid sufficient to be revealed by the diffraction experiment. These new data are compared with the diffraction patterns and the theoretical calculations of other choline-aminoacid ionic liquids recently reported. A significant role might be played by the stacking interactions between aromatic rings.

DiffractionChemical substancePhenylalanineStackingGeneral Physics and AstronomyPhenylalanine02 engineering and technologyIonic liquid010402 general chemistry01 natural sciencesCholinePhysics and Astronomy (all)chemistry.chemical_compoundAminoacidSettore CHIM/02Organic chemistryPhysical and Theoretical ChemistryAlkylcholine-amino acid ionic liquids EDXD; ion pairs; pre-peak; renewable materialschemistry.chemical_classificationSmall-angle X-ray scatteringSAXS; Choline; Phenylalanine; Aminoacids; Ionic liquidsAromaticitySAXS021001 nanoscience & nanotechnologyIonic liquids0104 chemical sciencesCrystallographychemistryIonic liquid0210 nano-technologyAminoacids
researchProduct

Weak alkali and alkaline earth metal complexes of low molecular weight ligands in aqueous solution

2008

This work is aimed at reviewing the chemical literature dealing with thermodynamic aspects of the weak complex formation (species with log K values less than about 3) between alkali and alkaline earth metal ions with low molecular weight inorganic and organic ligands in aqueous solution. The following ligands (up to hexavalent anions) were examined in detail: (i) hydroxide, chloride, sulfate, carbonate and phosphate as inorganic, and (ii) carboxylates, amines, amino acids, complexones and nucleotides as organic ligands. The paper also identifies the main reasons responsible for the dispersion of the stability data on ion pairs in the literature. When possible, the trend of stability for the…

Ion pairsSupporting electrolyteMetal ions in aqueous solutionInorganic chemistryAlkali metal complexeWeak complexesChlorideAlkali metal complexes; Alkaline earth metal complexes; Weak complexes; Formation and stability in aqueous solution; Ion pairs.Inorganic Chemistrychemistry.chemical_compoundAlkali metal complexesAlkaline earth metal complexesMaterials ChemistrymedicineFormation and stability in aqueous solutionSettore CHIM/01 - Chimica AnaliticaPhysical and Theoretical ChemistryWeak complexeAlkaline earth metalAqueous solutionChemistryLigandAlkali metalAlkaline earth metal complexeHydroxidemedicine.drugCoordination Chemistry Reviews
researchProduct

Apolar versus polar solvents: a comparison of the strength of some organic acids against different bases in toluene and in water

2010

The constants of ion-pair formation with 3-nitroaniline (3NO(2)A) for eight halogenoacetic acids (HAAs, 3a-h: TFA, TCA, TBA, DFA, DCA, DBA, MCA, and MBA), and five 2,2-dichloroalkanoic acids containing 3-8 carbon atoms (HAs, 5a-e: DCPA, DCBA, DCMBA, DCVA, and DCOA) have been determined in TOL at 298.1 K. The results obtained brought to evidence for HAAs the formation of ion-pairs with two different stoichiometries (base-acid, 1:1 or 1:2), while in contrast the HAs furnish only the 1:1 pairs. The different steric and electronic requirements of HAAs and HAs seem to be responsible for such an unlikely behavior. At the same time, the acid-catalyzed MRH of the (Z)-phenylhydrazone of 5-amino-3-be…

nitroanilinechemistry.chemical_classificationSteric effectsBase (chemistry)reazione di Boulton-Katritzskyacidi dicloroalcanoicichemistry.chemical_elementSettore CHIM/06 - Chimica Organicaacidi alogenoaceticiMedicinal chemistryTolueneMRH kinetic ion pairschemistry.chemical_compoundchemistryUreaPolarOrganic chemistryPhysical and Theoretical ChemistryCarbonreazione di Boulton-Katritzsky; nitroaniline; acidi alogenoacetici; acidi dicloroalcanoiciStoichiometry
researchProduct