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Please use this identifier to cite or link to this item: http://dspace.utalca.cl/handle/1950/10183

Title: Intramolecular Hydrogen Bond in Biologically Active o-Carbonyl Hydroquinones
Authors: Martinez-Cifuentes, M.
Weiss-Lopez, BE.
Santos, LS.
Araya-Maturana, R.
Keywords: molecular electrostatic potential;
natural bond orbital
hydroquinone
hydrogen bond
DFT
Issue Date: Jul-2014
Publisher: MDPI AG, POSTFACH
Citation: MOLECULES 19 (7) : 9354-9368
Abstract: Intramolecular hydrogen bonds (IHBs) play a central role in the molecular structure, chemical reactivity and interactions of biologically active molecules. Here, we study the IHBs of seven related o-carbonyl hydroquinones and one structurally-related aromatic lactone, some of which have shown anticancer and antioxidant activity. Experimental NMR data were correlated with theoretical calculations at the DFT and ab initio levels. Natural bond orbital (NBO) and molecular electrostatic potential (MEP) calculations were used to study the electronic characteristics of these IHB. As expected, our results show that NBO calculations are better than MEP to describe the strength of the IHBs. NBO energies (Delta E-ij((2))) show that the main contributions to energy stabilization correspond to LP ->sigma* interactions for IHBs, (O1O2)-O-center dot center dot center dot-H-2 and the delocalization LP ->pi* for O-2-C-2 = C-alpha(beta). For the (O1O2)-O-center dot center dot center dot-H-2 interaction, the values of Delta E-ij((2)) can be attributed to the difference in the overlap ability between orbitals i and j (F-ij), instead of the energy difference between them. The large energy for the LP O-2 ->pi* C-2 = C-alpha(beta) interaction in the compounds 9-Hydroxy-5-oxo-4,8, 8-trimethyl-1, 9(8H)-anthracenecarbolactone (VIII) and 9,10-dihydroxy-4,4-dimethylanthracen-1(4H)-one (VII) (55.49 and 60.70 kcal/mol, respectively) when compared with the remaining molecules (all less than 50 kcal/mol), suggests that the IHBs in VIII and VII are strongly resonance assisted.
Description: Univ Talca, Inst Quim Recursos Nat, Lab Sintesis Asimetr, Talca, Chile.Martinez-Cifuentes, M (Martinez-Cifuentes, Maximiliano); Santos, LS (Santos, Leonardo S.)
URI: http://dspace.utalca.cl/handle/1950/10183
ISSN: 1420-3049
Appears in Collections:Artículos en publicaciones ISI - Universidad de Talca

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