3651-02-3Relevant articles and documents
Tautomerism in 1-phenylazo-4-naphthols: Experimental results vs quantum-chemical predictions
Antonov, Liudmil,Kurteva, Vanya,Crochet, Aurelien,Mirolo, Laurent,Fromm, Katharina M.,Angelova, Silvia
, p. 714 - 723 (2012)
The reliability in the description of the tautomerism of 1-phenylazo-4-naphthol by using of HF and MP2 ab initio levels of theory and DFT methods with variety of pure GGA (OLYP), hybrid (B3LYP and B3PW91), long range corrected (LC-BLYP) and double-hybrid (B2PLYP and mPW2PLYP) functionals with large number of basis sets was estimated. In this evaluation three criteria were used: reproduction of the bond lengths in the structures of the individual tautomers, description of the non-planarity of the enol tautomer and prediction of the position of the tautomeric equilibrium (G value) at 298 K. The results show that in substantial number of cases HF reasonably covers all requirements. The tested pure (OLYP) and hybrid functionals (B3LYP and B3PW91) fail in the prediction of the position of the equilibrium independent on the basis set. The situation is slightly better at the long range corrected functional (LC-BLYP), which give predominance of the enol tautomer at 6-31+G (*) (*) and D95++ (*) (*). The double hybrid functionals give very good description with D95++ (*) (*) basis set, but at substantial computational costs.
Polar and Hydrogen-Bonding Interactions in Supercritical Fluids. Effects on the Tautomeric Equilibrium of 4-(Phenylazo)-1-naphthol
O'Shea, Kevin E.,Kirmse, Katherine M.,Fox, Marye Anne,Johnston, Keith P.
, p. 7863 - 7867 (1991)
The azo-hydrogen tautomeric equilibrium of 4-(phenylazo)-1-naphthol is compared in various liquid and supercritical fluid solvents.The less polar azo tautomer is dominant in the dilute gas phase, compressed ethane, and liquid alkanes.In liquid and supercritical CO2, the equilibrium shifts toward the more polar hydrazone, to yield similar amounts of the two tautomers.This shift is attributed to the Lewis acidity and large quadrupole moment of CO2.The dominance of the hydrazone tautomer in fluoroform (>90percent) can be attributed to that solvent's large dipole moment and ability to act as a strong electron acceptor (hydrogen bond donor).Since acid-base interactions are prevalent at the lowest pressure studied (1000 psia), changes in the equilibrium constant as a function of pressure have been assigned primarily to increases in the nonspecific polar interactions.The large differences in the polarities, acidities, and basicities of these fluids, despite their similar polarizabilities per volume, are of interest for manipulating chemical processes and for practical application of supercritical fluid science and technology.
Nano-Fe3O4 encapsulated-silica supported boron trifluoride as a novel heterogeneous solid acid for solvent-free synthesis of arylazo-1-naphthol derivatives
Bamoniri, Abdolhamid,Moshtael-Arani, Naimeh
, p. 16911 - 16920 (2015/03/30)
Nano-Fe3O4 encapsulated-silica supported boron trifluoride (Fe3O4@SiO2-BF3) as a new type of green heterogeneous solid acid was prepared by the immobilization of BF3·Et2O on the surface of Fe3O4@SiO2 core-shell nanoparticles and characterized by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), field emission-scanning electron microscope (FE-SEM), energy dispersive X-ray (EDS), and transmission electron microscope (TEM). Then, this super solid acid was used as an acidic reagent for the synthesis of aryl diazonium salts as a starting reactant, followed by its diazo coupling with 1-naphthol in a basic solvent-free medium at room temperature. The main advantages of this clean method were high yields, short reaction times, the possibility of performing it at room temperature, and no need of corrosive and toxic liquid acids and solvents. In addition, the long-term stability of aryl diazonium salts supported on Fe3O4@SiO2-BF3 magnetic nanoparticles (MNPs) at room temperature was one of the most important results of this procedure. This journal is
Nanosilica/NaNO2: Novel heterogeneous system for synthesis of Azo compounds
Jirandehi, Hassan Fathinejad,Mirzaeian, Marjan,Mirzaeian, Mojtaba
experimental part, p. 376 - 377 (2011/07/07)
Various azo compounds are synthesized by electrophonic substitution reaction in the presence of Nanosilica/NaNO2as a catalyst. Copyright Taylor & Francis Group, LLC.
