Vibrational characterization of azobenzenes, azoxybenzenes and azoaromatic and azoxyaromatic polyethers

Abstract

Raman and infrared spectra of a bisphenol-A-containing azoaromatic polyether, a bisphenol-A-containing azoxyaromatic polyether and a bisphenol-A-containing 2-hydroxyazoaromatic polyether were analyzed. Vibrational spectra were also collected for the corresponding model compounds 4,4º-(4-tert-butylphenoxy)azobenzene, 4,4º-(4-tert-butylphenoxy)azoxybenzene and 4,4º-(4-tert-butylphenoxy)-2-hydroxyazobenzene. Comparisons with substituted azobenzenes and azoxybenzenes were used in assigning the spectra in the 1650-900 cm-1 region. Assignments of the NxN stretch (1410-1390 cm-1) demonstrate that all of the compounds are in the trans conÐguration. The azo bridge vibrations of the azoaromatic ethers are very similar to those of azobenzene. Di †er-ent types of hydrogen bonding are seen in the 2-hydroxyazoaromatic compounds. The polyether has an OH stretch at 3355 cm-1 which indicates a network of intermolecular hydrogen bonds among the polymers. The 2-hydroxyazoaromatic model compound has no IR peak above 3100 cm-1 and NxN, CO and CN stretches which are shifted due to an intramolecular hydrogen bond with the azo nitrogen. The NxN stretch of the azoxyaromatic ethers is at the same wavenumber as in the azo compounds. Assignment of the N Ç O stretch vibration is difficult because of mixing with other modes of the azoxy bridge.

Theoretical investigations on the structural, spectroscopic, electronic and thermodynamic properties of (3-Oxo-3H-benzo[f]chromen-1yl) methyl N,N-dimethylcarbamodithioate-1ex

“…The C-N stretching vibrations are observed in 1382 cm −1 to 1266 cm −1 [45], 1150 cm −1 to 1120 cm −1 [47], and 1248 cm −1 to 1199 cm −1 [48]. In this study, we have observed the C-N stretching vibrations at Table 2).…”

Quantum chemical studies on the molecular structure, spectroscopic and electronic properties of (6-Methoxy-2-oxo-2H-chromen-4-yl)-methyl pyrrolidine-1-carbodithioate

“…Silverstein et al [31] identified the C-N stretching absorption in the region of 1382 cm −1 to 1266 cm −1 for aromatic amines. Tecklenburg et al [48] located the C-N symmetric stretch in the region of 1120 cm −1 to 1150 cm −1 . The C-N stretchings were also found to be present at 1248 cm −1 and 1199 cm −1 by Pajazk et al [49].…”

Quantum mechanical investigation of the tautomerism in the azo dye Sudan III

“…Aromatic azo derivatives constitute a broad class of compounds with interesting optical properties. Their practical and theoretical importance has been reflected in the great number of studies of structure and spectroscopic investigations of analogous chemical systems 1–23. Despite the electronic effects of the substituents attached to the phenyl rings, some physical‐chemical processes are directly related to the optical characteristics of azobenzene compounds.…”

“…Electronic and vibrational assignments were reported, and the results led the authors to conclude that the azo form is likely to be dominant for the molecules considered. Tecklenburg and coworkers 21 reported a vibrational characterization of azo aromatic and hydroxyazo aromatic polyethers. The azo‐hydrazone tautomerism was investigated with the azo form found in greater concentration in the solid state.…”