A novel azocompound, 2‐(4‐phenylazoaniline)‐4‐phenylphenol: Spectroscopic and quantum‐chemical approach

Abstract

A novel azocompound with two nonequivalents azo groups, 2‐(4‐phenylazoaniline)‐4‐phenylphenol, was synthesized and characterized by spectroscopic and computational analysis. An intramolecular hydrogen bonding (HB), O1H1···N1, involving the N1N2 group and the proton in a neighbor hydroxyl moiety, was identified. It was found responsible for a characteristic π‐conjugated H1O1C18C13N2N1 six‐membered cyclic fragment. It is worth noting that this azo group is involved in an azo‐hydrazo equilibrium, being the azo form the most stable one. This resonance‐assisted HB was characterized using the OH‐related infrared bands and the corresponding signals in 1H NMR. In addition, conformational studies and geometrical and electronic parameter calculations were performed using the density functional theory, at B3LYP/6‐311++G** level. Bond and ring critical points were identified using the atoms in molecules theory, which allowed confirming the intramolecular HB. The second azo‐group cannot be involved in HB, but it also presents two stereoisomerics forms corresponding to cis (Z) and trans (E) configurations, with the later being the one with the lowest energy. © 2013 Wiley Periodicals, Inc.

Computational Characterization of Perezone, Isoperezone and their Sulfur‐Derivatives: Anti‐inflammatory Activity.

“…The analyses are focused on selected vibrational modes: C1 = O1, C4 = O4, C3-O3, and OÀ H bands for all molecules, in addition to C6-H and C3-H for perezone and isoperezone respectively, and C6-S for perezone sulfurs and C3-S for isoperezone sulfurs. The harmonic frequencies, with scaling factor (0.9679) [27,[38][39][40] of the selected modes were compared to the available experimental data. Some selected calculated harmonic frequencies and the descriptions concerning the assignment are listed in Table 5 and were compared with the experimental data.…”

“…The calculated frequencies were scaled to compensate the approximate treatment of electron correlation, basis set deficiencies and for the anharmonicity . In this sense, the base set, 6–311++G(d,p), has been used to evaluate appropriately, both the vibrational analysis and the NMR data with good approximations, for various organic molecules …”

“…[24][25][26] In this sense, the base set, 6-311 + + G(d,p), has been used to evaluate appropriately, both the vibrational analysis and the NMR data with good approximations, for various organic molecules. [27][28][29] It is important to highlight, that our research group is interested in the spectroscopic theoretical and experimental correlation of interesting compounds, mainly by IR and NMR; [30][31] this in addition, to the performance of computational studies in order to explain their biological activity.…”

Initial reaction mechanism between HO· and bisphenol‐F: Conformational dependence and the role of nonbond interactions

“…Significant differences of the electrostatic potential distribution can be found within oo_c, op_c, and pp_c. The O—H…O hydrogen bond formation in oo_c lead to increased electrostatic potential around the hydroxyl pairs . For op_c and pp_c, the maximum electrostatic potential regions are dispersed in the two ends of the molecules.…”

A DFT Study of the Geometrical, Spectroscopical and Reactivity Properties of Diindolylmethane-Phenylboronic Acid Hybrids

“…In general, negative values of ∇ 2 ρ ( r ) are typical of covalent interactions, whereas interactions between closed−shell systems are characterized by positive values of ∇ 2 ρ ( r ). Some topological criteria of the existence of HB have been proposed [ 54 , 55 , 56 ]. The following are the most common criteria applied to study HB interactions: A BCP must be located within the H●●●A contact region, which topologically proves an increase in the density and consequence the existence of HB; The value of the electron density of the BCP arising from the H●●●A interaction, which should range between 0.002 and 0.040 a.u.…”