Hydrogen bonding probes of phenol -OH groups
Φόρτωση...
Ημερομηνία
Συγγραφείς
Kontogianni, V. G.
Charisiadis, P.
Primikyri, A.
Pappas, C. G.
Exarchou, V.
Tzakos, A. G.
Gerothanassis, I. P.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Royal Society of Chemistry
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Organic and Biomolecular Chemistry
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
Correlations between hydrogen bonds and solvent effects on phenol -OH proton shieldings, temperature coefficients (Delta delta/Delta T) and effects on OH diffusion coefficients for numerous phenolic acids, flavonols, flavones, and oleuropein derivatives of biological interest were investigated in several organic solvents and were shown to serve as reliable indicators of hydrogen bonding and solvation state of -OH groups. The temperature coefficients span a range of -0.5 to -12.3 ppb K-1. Shielding differences of 2.0 to 2.9 ppm at 298 K were observed for solvent exposed OH groups between DMSO-d(6) and CD3CN which should be compared with a shielding range of similar to 7 ppm. This demonstrates that the solvation state of hydroxyl protons is a key factor in determining the value of the chemical shift. For -OH protons showing temperature gradients more positive than -2.5 ppb K-1, shielding changes between DMSO-d(6) and CD3CN below 0.6 ppm, and diffusion coefficients significantly different from those of traces of H2O, there is an intramolecular hydrogen bond predictivity value of 100%. The C-3 OH protons of flavonols show very significant negative temperature coefficients and shielding changes between DMSO-d(6) and CD3CN of similar to 2.3 ppm, which indicate the absence of persistent intramolecular hydrogen bonds, contrary to numerous X-ray structures.
Περιγραφή
Λέξεις-κλειδιά
magnetic-resonance-spectroscopy, h-1-nmr chemical-shifts, aqueous-solution, conformational-analysis, temperature-dependence, molecular-structures, crystal-structure, nmr-spectroscopy, hydroxyl protons, ab-initio
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://000313664100018
http://pubs.rsc.org/en/Content/ArticleLanding/2013/OB/c2ob27117f
http://pubs.rsc.org/en/Content/ArticleLanding/2013/OB/c2ob27117f
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας