Role of the functional group in the formation of the complexes between α-cyclodextrin and alkanols or monocarboxylic acids in aqueous solutions. A calorimetric study at 25 °C

1998 ◽  
Vol 306 (1-2) ◽  
pp. 147-155 ◽  
Author(s):  
Giuseppina Castronuovo ◽  
Vittorio Elia ◽  
Marcella Niccoli ◽  
Filomena Velleca ◽  
Giuseppe Viscardi
Keyword(s):  
Aqueous Solutions ◽  
Functional Group ◽  
Calorimetric Study ◽  
Monocarboxylic Acids

Chiral recognition in aqueous solutions at 25 °C. A calorimetric study of the interaction between enantiomeric α-amino acids of different alkyl chain length

1991 ◽  
Vol 69 (5) ◽  
pp. 794-797 ◽  
Author(s):  
Giuseppina Castronuovo ◽  
Vittorio Elia ◽  
Michela Magliulo
Keyword(s):  
Amino Acids ◽  
Aqueous Solutions ◽  
Chiral Recognition ◽  
Excess Enthalpy ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Calorimetric Study ◽  
Experimental Uncertainty ◽  
Enthalpies Of Dilution

Cross-homo- and cross-heterotactic enthalpic coefficients, [Formula: see text] respectively, were determined at 25 °C, measuring the enthalpies of dilution of ternary aqueous solutions containing two different α-amino acids of the same or different chirality. Differences of about 200–300 J mol−2 kg between cross-homo- and cross-heterotactic coefficients were found, well beyond the experimental uncertainty. The role of the zwitterionic interaction, already proposed to explain the nature of chiral recognition, was strengthened. Key words: α-amino acids, excess enthalpy, chiral recognition.

scholarly journals New Precursors to 3-Sulfanylhexan-1-ol? Investigating the Keto–Enol Tautomerism of 3-S-Glutathionylhexanal

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4261
Author(s):  
Jennifer R. Muhl ◽  
Lisa I. Pilkington ◽  
Rebecca C. Deed
Keyword(s):  
Aqueous Solutions ◽  
Functional Group ◽  
Enol Form ◽  
Keto Form ◽  
White Wines ◽  
Sauvignon Blanc ◽  
Thiol Compound ◽  
Volatile Precursors ◽  
First Time

The volatile thiol compound 3-sulfanylhexan-1-ol (3SH) is a key impact odorant of white wines such as Sauvignon Blanc. 3SH is produced during fermentation by metabolism of non-volatile precursors such as 3-S-gluthathionylhexanal (glut-3SH-al). The biogenesis of 3SH is not fully understood, and the role of glut-3SH-al in this pathway is yet to be elucidated. The aldehyde functional group of glut-3SH-al is known to make this compound more reactive than other precursors to 3SH, and we are reporting for the first time that glut-3SH-al can exist in both keto and enol forms in aqueous solutions. At wine typical pH (~3.5), glut-3SH-al exists predominantly as the enol form. The dominance of the enol form over the keto form has implications in terms of potential consumption/conversion of glut-3SH-al by previously unidentified pathways. Therefore, this work will aid in the further elucidation of the role of glut-3SH-al towards 3SH formation in wine, with significant implications for the study and analysis of analogous compounds.

Thermodynamics of the interaction of α-cyclodextrin with monocarboxylic acids in aqueous solutions: a calorimetric study at 25 °C

1996 ◽  
Vol 287 (2) ◽  
pp. 127-138 ◽  
Author(s):  
Giuseppina Castronuovo ◽  
Vittorio Elia ◽  
Dimitrios Fessas ◽  
Filomena Velleca ◽  
Giuseppe Viscardi
Keyword(s):  
Aqueous Solutions ◽  
Calorimetric Study ◽  
Monocarboxylic Acids

Role of functional groups in determining interactions in ternary aqueous solutions of enantiomeric α-amino acids: a calorimetric study at 298 K

1999 ◽  
Vol 1 (24) ◽  
pp. 5653-5657 ◽  
Author(s):  
Giuseppina Castronuovo ◽  
Vittorio Elia ◽  
Marcella Niccoli ◽  
Daniela Strollo ◽  
Filomena Velleca
Keyword(s):  
Amino Acids ◽  
Aqueous Solutions ◽  
Functional Groups ◽  
Calorimetric Study

On the Structure of Lead(II) Complexes in Aqueous Solutions. I. Trinuclear Clusters

1995 ◽  
Vol 60 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová
Keyword(s):  
Quantum Chemistry ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
Mndo Method ◽  
Model Systems ◽  
Trinuclear Clusters ◽  
The Stability ◽  
Semiempirical Mndo

Using semiempirical MNDO method of quantum chemistry the optimal geometries and corresponding electronic structures of [Pb3(OH)n]6-n model systems as well as of their hydrated [Pb3(OH)n(H2O)8-n]6-n analogues (n = 4, 5) are investigated. The most stable trinuclear lead(II) complexes present in aqueous solutions correspond to cyclo-(μ3-OH)(μ2-OH)3Pb32+, Pb(μ-OH)2Pb(μ-OH)2Pb2+, cyclo-(μ3-OH)2(μ2-OH)3Pb3+, Pb(OH)(μ-OH)2Pb(μ-OH)Pb(OH)+ and Pb(OH)(μ-OH)2Pb(μ-OH)2Pb+ systems. The key role of OH bridges (by vanishing direct Pb-Pb bonds) on the stability of individual isomers is discussed.

scholarly journals Wood Pastures: A Transitional Habitat between Forests and Pastures for Dung Beetle Assemblages

Forests ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
László Somay ◽  
Viktor Szigeti ◽  
Gergely Boros ◽  
Réka Ádám ◽  
András Báldi
Keyword(s):  
Functional Group ◽  
Animal Health ◽  
Habitat Type ◽  
Dung Beetle ◽  
Dung Beetles ◽  
Livestock Grazing ◽  
Pitfall Traps ◽  
Assemblage Composition ◽  
Beetle Assemblages

Wood pastures are home to a variety of species, including the dung beetle. Dung beetles are an important functional group in decomposition. Specifically, in terms of livestock manure, they not only contribute to nutrient cycling but are key players in supporting human and animal health. Dung beetles, however, are declining in population, and urgent recommendations are needed to reverse this trend. Recommendations need to be based on solid evidence and specific habitats. Herein, we aimed to investigate the role of an intermediate habitat type between forests and pastures. Wood pastures are key areas for dung beetle conservation. For this reason, we compared dung beetle assemblages among forests, wood pastures, and grasslands. We complemented this with studies on the effects of dung type and season at three Hungarian locations. Pitfall traps baited with cattle, sheep, or horse dung were used in forests, wood pastures, and pasture habitats in spring, summer, and autumn. Dung beetle assemblages of wood pastures showed transient characteristics between forests and pastures regarding their abundance, species richness, Shannon diversity, assemblage composition, and indicator species. We identified a strong effect of season and a weak of dung type. Assemblage composition proved to be the most sensitive measure of differences among habitats. The conservation of dung beetles, and the decomposition services they provide, need continuous livestock grazing to provide fresh dung, as well as the maintenance of wood pastures where dung beetle assemblages typical of forests and pastures can both survive.

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