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.     

UV absorption spectra of some γ-phenylpyridine derivatives

The derivatives have methyl, carbethoxy, and carbmethoxy groups or are higher homologs with unsaturated substituents. The bond orders and electron density per atom are calculated by the LCAO MO method in the Hückel approximation for the parent compound and the methyl derivatives. The spectra are recorded with an EPS-2 spectrophotometer, the solvents being ethanol and isooctane.The compounds were synthesized in the organic chemistry at the Lumumba Friendship University by K.J. Mathew and A.I. Sirotin under the direction of Professor N.S. Prostakov.     

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.     

Optical absorption spectra of some transition metal thiophosphates

Near-infrared and visible absorption spectra at room temperature of MnPS₃, CoPS₃, CoPS₃ are reported. These materials show weak structures below their fundamental absorption thresholds, due to the 3d-3d transitions occurring on the transition metal ion. By comparison with other transition metal compounds, such excitations are interpreted on the basis of the ligand field theory. The appearance of well developed crystal field spectra is a further confirmation that these materials are considerably ionic.