TY - JOUR
T1 - Energetic and Structural Properties of Two Phenolic Antioxidants
T2 - Tyrosol and Hydroxytyrosol
AU - Dávalos, Juan Z.
AU - Valderrama-Negrón, Ana C.
AU - Barrios, Julio R.
AU - Freitas, Vera L.S.
AU - Ribeiro Da Silva, Maria D.M.C.
N1 - Funding Information:
This work is dedicated to Prof. Walter Estrada (Facultad de Ciencias, Universidad Nacional de Ingenieria,́ Lima-Peru).́ J.Z.D. thanks the Peruvian PNICP (INNÓVATE PERÚ, ECIP-1-P-030-14 for a grant. Part of this work was developed within the scope of the projects UID/QUI/0081/2013, POCI-01-0145-FEDER-006980, and NORTE-01-0145-FEDER-000028 (“Sustained Advanced Materials”), awarded to CIQUP, financed by Fundaca̧ õ para a Ciencia e Tecnologia (FCT), Lisbon, Portugal, andcofinanced in the framework of Operational Programme for Competitiveness and Internationalisation, COMPETE, with community funds (FEDER) and national funds of MEC. V.L.S.F. also thanks FCT, European Social Fund (ESF), and the national funds of MEC for the award of Postdoctoral Grant SFRH/BPD/78552/2011.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/4/26
Y1 - 2018/4/26
N2 - Theoretical and experimental studies on the energetic, structural and some other relevant physicochemical properties of the antioxidant tyrosol (1), hydroxytyrosol (1OH) molecules and the corresponding radicals 1rad• and 1Orad• are reported in this work. The experimental values of the gas-phase enthalpy of formation, ΔfHm0(g), in kJ·mol-1, of 1 (-302.4 ± 3.4) and 1OH (-486.3 ± 4.1) have been determined. Quantum chemical calculations, at DFT (M05-2X) and composite ab initio G3 and G4 levels of theory, provided results that served to (i) confirm the excellent consistency of the experimental measurements performed, (ii) establish that the stabilizing effect of H-bond of hydroxyethyl chain and aromatic ring (OH···π interaction) is smaller in radicals than in parent molecules, (iii) deduce - combining experimental data in isodesmic reactions - ΔfHm0(g) of radicals 1rad• (-152.3 ± 4.4 kJ·mol-1) and 1Orad• (-370.6 ± 3.8 kJ·mol-1), (iv) estimate a reliable O-H bond dissociation enthalpy, BDE of 1 (368.1 ± 5.6 kJ·mol-1) and of 1OH (333.7 ± 5.6 kJ·mol-1), and (v) corroborate - using "BDE criteria" - than 1OH is a more effective antioxidant than 1.
AB - Theoretical and experimental studies on the energetic, structural and some other relevant physicochemical properties of the antioxidant tyrosol (1), hydroxytyrosol (1OH) molecules and the corresponding radicals 1rad• and 1Orad• are reported in this work. The experimental values of the gas-phase enthalpy of formation, ΔfHm0(g), in kJ·mol-1, of 1 (-302.4 ± 3.4) and 1OH (-486.3 ± 4.1) have been determined. Quantum chemical calculations, at DFT (M05-2X) and composite ab initio G3 and G4 levels of theory, provided results that served to (i) confirm the excellent consistency of the experimental measurements performed, (ii) establish that the stabilizing effect of H-bond of hydroxyethyl chain and aromatic ring (OH···π interaction) is smaller in radicals than in parent molecules, (iii) deduce - combining experimental data in isodesmic reactions - ΔfHm0(g) of radicals 1rad• (-152.3 ± 4.4 kJ·mol-1) and 1Orad• (-370.6 ± 3.8 kJ·mol-1), (iv) estimate a reliable O-H bond dissociation enthalpy, BDE of 1 (368.1 ± 5.6 kJ·mol-1) and of 1OH (333.7 ± 5.6 kJ·mol-1), and (v) corroborate - using "BDE criteria" - than 1OH is a more effective antioxidant than 1.
UR - https://www.scopus.com/pages/publications/85046032814
U2 - 10.1021/acs.jpca.8b00457
DO - 10.1021/acs.jpca.8b00457
M3 - Artículo (Contribución a Revista)
C2 - 29616550
AN - SCOPUS:85046032814
SN - 1089-5639
VL - 122
SP - 4130
EP - 4137
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 16
ER -