chemistry journal of moldova

Chemistry Journal of Moldova. General, Industrial and Ecological Chemistry. 2008, 3 (1), 3-7FULL PAPER INDUSTRIAL CHEMISTRY 85SPECTROPHOTOMETRIC STUDIES OF SANGUINARINE--CYCLODEXTRIN COMPLEX FORMATIONVeaceslav Boldescu, Irina Kacso, Ioan Bratu and Gheorghe DucaThe influence of pH and the presence of hydrophilic polymer polyvinylpyrrolidone on theformation of sanguinarine--cyclodextrin (SANG--CD) inclusion complex was investigated.Spectrophotometric studies of the SANG--CD systems in the presence and without 0.1 % PVPat the pH 5.0 did not show any evidence of the complex formation. However, the same systemsshowed several obvious evidences at the pH 8.0: the hyperchromic and the hypochromic effectsand the presence of the isosbestic point in the region of 200 – 210 nm.FULL PAPER NATURAL PRODUCT CHEMISTRY AND SYNTHESIS 89STEROIDAL SAPONINS FROM THE SEEDS OF HYOSCYAMUS NIGER L.Irina Lunga, Pavel Kintia, Stepan Shvets, Carla Bassarelo, Sonia Piacente and Cosimo PizzaThe paper reports on the isolation of steroidal glycosides from the seeds of Hyoscyamus niger L. for the first time.Hyoscyamosides B (1), C(2) and C 2 (3) represent new compounds, their structures being determined by physico-chemicalmethods.HMeOMe O MeMeMeMeOMeROH1: R=Glc(1-3)Gal 3: R=Glc(1-2)Glc(1-4)Gal2: R=[Glc(1-3)][Glc(1-2)]GalROHFULL PAPER PYSICAL CHEMISTRY AND CHEMICAL PHYSICS 94TOXICOPHORES AND QUANTITATIVE STRUCTURE -TOXICITY RELATIONSHIPS FOR SOMEENVIRONMENTAL POLLUTANTSN. N. Gorinchoy, I. Ya. Ogurtsov, A. Tihonovschi, I. Balan, I. B. Bersuker, A. Marenich and J.BoggsThe electron-conformational (EC) method is employed to reveal thetoxicophore and to predict aquatic toxicity quantitatively using as atraining set a series of 51 compounds that have aquatic toxicity to fish.By performing conformational analysis (optimization of geometries ofthe low-energy conformers by the PM3 method) and electronic structurecalculations (by ab initio method corrected within the SM54/PM3solvatation model), the Electron-Conformational Matrix of Congruity(ECMC) was constructed for each conformation of these compounds.FULL PAPER PYSICAL CHEMISTRY AND CHEMICAL PHYSICS 105VIBRONIC ORIGIN OF THE “SKEWED” ANTICLINE CONFIGURATION OF THE HYDROGENPEROXIDE MOLECULEN. N. Gorinchoy, I. Ya. Ogurtsov and Ion ArseneThe vibronic origin of the instability of the symmetrical forms (D h , C 2hand C 2v ) of the hydrogen peroxide molecule H 2 O 2 was revealed using abinitio calculations of the electronic structure and the adiabatic potentialenergy curves. The vibronic constants in this approach were estimatedby fitting of the ab initio calculated adiabatic potential in the vicinity ofthe high-symmetry nuclear configurations to its analytical expression. Itwas shown that the equilibrium "skewed" anticline shape of the C 2symmetry can be realized in two ways: D h C 2v C 2 or D h C 2v C 2 with the decreasing of the adiabatic potential energy at every step.6