scholarly journals The Role of Hydrogen Bond Donor on the Extraction of Phenolic Compounds from Natural Matrices Using Deep Eutectic Systems

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2336
Author(s):  
Duarte Rente ◽  
Alexandre Paiva ◽  
Ana Rita Duarte
Keyword(s):  
Hydrogen Bond ◽  
Phenolic Compounds ◽  
Comprehensive Evaluation ◽  
Critical Role ◽  
Carbon Chain ◽  
Carbon Chain Length ◽  
Carbonyl Groups ◽  
Hydrogen Bond Donor ◽  
Eutectic Systems

Recently, deep eutectic systems (DESs) as extraction techniques for bioactive compounds have surfaced as a greener alternative to common organic solvents. In order to study the effect of these systems on the extraction of phenolic compounds from different natural sources, a comprehensive review of the state of the art was carried out. In a first approach, the addition of water to these systems and its effect on DES physicochemical properties such as polarity, viscosity, and acidity was investigated. This review studied the effect of the hydrogen bond donor (HBD) on the nature of the extracted phenolics. The effects of the nature of the HBD, namely carbon chain length as well as the number of hydroxyl, methyl, and carbonyl groups, have shown to play a critical role in the extraction of different phenolic compounds. This review highlights the differences between DES systems and systematizes the results published in the literature, so that a more comprehensive evaluation of the systems can be carried out before any experimental trial.

Interplay between dipolar, stacking and hydrogen-bond interactions in the crystal structures of unsymmetrically substituted esters, amides and nitriles of (R,R)-O,O′-dibenzoyltartaric acid

2001 ◽  
Vol 57 (3) ◽  
pp. 415-427 ◽  
Author(s):  
Urszula Rychlewska ◽  
Beata Warżajtis
Keyword(s):  
Hydrogen Bond ◽  
Molecular Conformation ◽  
Crystal Packing ◽  
Carbon Chain ◽  
Mutual Orientation ◽  
Carbonyl Groups ◽  
Hydrogen Bond Donor ◽  
Hydrogen Bond Interactions ◽  
Classical Hydrogen Bond ◽  
Small Change

The compounds analysed are the O,O′-dibenzoyl derivatives of (R,R)-tartaric acid, asymmetrically substituted by ester, amide and nitrile groups. Benzoylation does not introduce drastic changes to the molecular conformation. All investigated molecules adopt the planar T conformation of the four-carbon chain with noticeably smaller departures from the ideal conformation than observed in the nonbenzoylated analogs. Primary and secondary amides always orient the C=O bond antiperiplanar (a) with respect to the nearest C*—O bond, while methylester groups adjust their conformation to that adopted by the amide substituent situated at the other end of the molecule. Tertiary amides and carboxyl groups place their carbonyls at the same side as the nearest C*—O bond (the s form), but often deviations from coplanarity of the two bonds are significant and higher than those observed in the nonbenzoylated series. The results presented demonstrate the importance of dipole/dipole interactions between CO and βC*H groups in stabilizing the molecular conformation, and between carbonyl groups in stabilizing crystal packing of the molecules that lack classical hydrogen-bond donor groups. An illustration is provided as to how a small change in mutual orientation of molecules arranged in a close-packed fashion causes a change in the character of intermolecular interactions from van der Waals to sandwich stacking between the benzoyloxy phenyls, and to dipolar between the benzoyloxy carbonyls. Hydrogen-bonded molecules tend to orient in a head-to-tail mode; the head-to-head arrangement being limited to cases in which terminal carbonyl groups are situated at one side of the molecule. The orientation of the benzoyloxy substituents with respect to the carbon main chain is such that the (O=)C—O—C—H bond system often deviates significantly from planarity.

Role of the hydrogen bond donor component for a proper development of novel hydrophobic deep eutectic solvents

2019 ◽  
Vol 281 ◽  
pp. 423-430 ◽  
Author(s):  
Matteo Tiecco ◽  
Federico Cappellini ◽  
Francesco Nicoletti ◽  
Tiziana Del Giacco ◽  
Raimondo Germani ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Deep Eutectic Solvents ◽  
Hydrogen Bond Donor

scholarly journals Fluorination as a route towards unlocking the hydrogen bond donor ability of phenolic compounds in self-assembled monolayers

CrystEngComm ◽  
2020 ◽  
Vol 22 (14) ◽  
pp. 2425-2428
Author(s):  
Harry Pinfold ◽  
Graham Pattison ◽  
Giovanni Costantini
Keyword(s):  
Hydrogen Bond ◽  
Phenolic Compounds ◽  
Building Block ◽  
Self Assembled Monolayers ◽  
Hydrogen Bond Donor ◽  
Assembled Monolayers ◽  
Donor Ability ◽  
Self Assembled ◽  
Effective Hydrogen

Fluorination turns a prototypical diphenol into an effective hydrogen-bond-donating building block for the formation of 2D phenol–pyridine cocrystals.

The formation and destruction of pentenes during the combustion of pentane

1978 ◽  
Vol 364 (1716) ◽  
pp. 75-88 ◽  
Keyword(s):  
Chain Length ◽  
Sharp Decrease ◽  
Carbon Chain ◽  
Carbon Chain Length ◽  
Reactivity Ratios ◽  
Direct Products ◽  
Specific Activities ◽  
Kinetics Of ◽  
Quantitative Importance

Studies have been made of the quantitative rôle of pent-1-ene and pent-2-ene in the combustion of pentane at temperatures below 400°C. The present results show that, under these conditions, pentenes are initial and direct products of pentane combustion and pent-2-ene is the principal conjugate alkene formed [1- 14 C]Pent-1-ene and [2- 14 C]pent-2-ene have been synthesized and the combustion of pentane has also been investigated in the presence of small concentrations of these specifically labelled com­pounds; control experiments have shown that the pentenes, in the amounts added, do not interfere appreciably with the kinetics of pentane combustion. Measurements of the variation with time of the specific activities and concentrations of the pentenes enable the separate rates of formation and destruction of the conjugate alkenes to be determined. Hence it is possible to calculate the total quantities of these compounds formed at different stages of reaction and to show to what extent these are greater than the net amounts revealed by conventional analytical measurements; the differences are found to be most marked at small conversions. The reactivity ratios of pentane and the pentenes have also been determined. The rates of destruction of both pentenes are much greater than that of pentane; pent-2-ene is removed from the system roughly twice as fast as pent-1-ene. An important contrast between the behaviour of pentane and butane is that, between 300 and 400°C, but-1-ene is a much more abundant product than but-2-ene. However, with both alkanes, the relative amounts of the alk-1-enes formed become greater as the temperature is increased; indeed, the rate of formation of pent-1-ene considerably exceeds that of pent-2-ene at the instant of the passage of a strong cool flame. Comparison of the total amounts of conjugate alkenes formed from the two alkanes at 315°C shows that only ca . 30% of the pentane consumed is converted to pentenes, whereas nearly 75% of the butane which has reacted is converted to butenes. Thus there is clearly a sharp decrease in the quantitative importance of conjugate alkenes as the carbon chain length is increased from C 4 to C 5 . This suggests that the predominant reaction of pentyl radicals, under the conditions used, is to add on oxygen to form pentylperoxy radicals.

Dual Role of the 1,2,3-Triazolium Ring as a Hydrogen-Bond Donor and Anion-π Receptor in Anion-Recognition Processes

2015 ◽  
Vol 21 (27) ◽  
pp. 9797-9808 ◽  
Author(s):  
Fabiola Zapata ◽  
Lidia Gonzalez ◽  
Antonio Caballero ◽  
Ibón Alkorta ◽  
Jose Elguero ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Anion Recognition ◽  
Dual Role ◽  
Hydrogen Bond Donor

Role of Molecular Structure of Complexing/Chelating Agents in Copper CMP Slurries

2005 ◽  
Vol 867 ◽  
Author(s):  
Udaya B. Patri ◽  
S. Pandija ◽  
S.V. Babu
Keyword(s):  
Molecular Structure ◽  
Functional Groups ◽  
Chelating Agents ◽  
Carbon Chain ◽  
Carbon Chain Length ◽  
Removal Rates ◽  
Ph Values ◽  
Amino Butyric Acid ◽  
Acidic Conditions

AbstractThe role of the molecular structure - different functional groups, the length of the carbon chain and the relative positions of different functional groups – of several complexing/chelating agents (acetic acid, glycine, ethylene diamine, succinic acid, alanine and amino butyric acid (ABA)) in controlling copper (Cu) removal rates was investigated. The results are consistent with the known activity of –COOH groups at acidic conditions and that of –NH2 groups in an alkaline environment. In comparison with glycine, it was also observed that an increase in the carbon chain length increased the removal rates at acidic pH values and decreased the removal rates at alkaline pH values. Also, Cu removal rates decreased with an increase in the distance between the –NH2 and –COOH groups in an amino acid at all pH values except at 4.

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