Electronic absorption spectra of antiviral aminophenol derivatives

Electronic absorption spectra of aminophenol derivatives in solutions have been studied. A general property of the absorption spectra of these compounds, the dependence of the maximum of a long-wavelength absorption band on the solvent polarity, is revealed. As a rule, the absorption band maximum of compounds possessing pharmacological properties shows a greater shift to short wavelength with an increase in the medium polarity than that of inactive compounds. Absorption measurements of solutions of aminophenol derivatives can be used for a tentative estimation of their antiviral activity.     

Electronic and vibrational absorption spectra in falcondoite

Optical absorption spectrum of Ni²⁺ ion in Falcondoite, a new mineral has been studied at 300 K. From the nature and positions of the observed bands a succesful interpretation of all the bands could be made assuming octahedral symmetry for the Ni²⁺ ion in the crystal. The bands at 9255, 15 380 and 27 390cm⁻¹ are assigned to ³T_2g(F), ³T_1g and ³T_1g(P) and the other band at 24385 cm⁻¹ assigned to ¹T_2g(D). The crystal field and the Racah parameters are evaluated to be Dq = 925 cm⁻¹, B = 1000 cm⁻¹ and C = 4095 cm⁻¹. NIR and IR spectra of the sample are also studied. The fundamental vibrational modes of H₂O are identified in the IR spectrum. The bands observed in the NIR spectrum are due to overtones and combination tones of water molecule.     

The spectroscopy of salicylaldehydes: Electronic absorption spectra

Measurements of the electronic absorption spectra of vapor- and solution-phase salicylaldehydes are reported for wavelengths ≥1900 Å. Three intense absorption band systems are readily assigned as $\text{A′ (ππ}{}^1\text{) ← 1}{}^1\text{A′}$ transitions by comparison with all-valence-electron computations. Moderate vibrational structure in the $\text{3}{}^1\text{A′ (ππ}{}^1\text{) ← 1}{}^1\text{A′}$ transitions of isotopic salicylaldehydes is analyzed and tentative assignments are made for the coupled vibrations.     

Electronic absorption spectra of L-ascorbic acid in nonaqueous media

An Electronic spectroscopic study of the self-association of Vitamin C in the nonaqueous phase is reported, pre-sumably for the first time. The oxidation of ascorbic acid in 1,4-dioxane has been studied by UV spectroscopy. The dramatic role of the environment in the stability and identification of the possible intermediates formed in the oxidation of ascorbic acid is shown. Published in Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 2, pp. 263–265, March–April, 2006.     

Electronic absorption spectra of hydrogenated quinolines in various solvents

Data are given on _max and _max for dihydro- and tetrahydroquinolines in various solvents. The effects of structure on molecular interaction are discussed.     

Electronic absorption spectra of CCS and CCS in neon matrices

Mass selected C₂S⁻ ions have been co-deposited with neon to grow a matrix at 6 K. The and electronic absorption spectra of the linear CCS⁻ anion have been identified with origin band at 10 606 and 22 273 cm⁻¹, respectively. After exposure to UV radiation a new electronic transition of CCS is observed (origin band at 30 563 cm⁻¹) in addition to its known band system. Ab initio calculations provide support for the symmetry assignment of the upper electronic states of CCS⁻, CCS and of the vibrational structure in the spectra.