Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Polish Journal of Chemistry

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Flavin-related Compounds: 3-Ethyl-lumiflavin. Combined DFT, NMR, X-ray and EI Mass Spectral Study

Sikorska E., Hernando J., Bourdelande J. L., Khmelinskii I., Kubicki M., Komasa A., Prukała D., Sikorski M.

Polish Journal of Chemistry

2008

Vol. 82, nr 11

2141-2152

3-Ethyl-lumiflavin was characterized by a variety of methods. Laser flash photolysis measurements in methanol solutions yielded a triplet state living 9.5 ms and a radical species living 91mi s, with steady-state photolysis quantum yields below 10-5. Fluorescence life time of 4.5 ns and quantum yield of 0.16 was recorded in aqueous solu tions. Crystal structure determined by X-ray diffraction was quite similar to the geometry of an isolated molecule calculated using the DFT approach, with the observed differences attributable to a non linear hydrogen bond existing in the crystal solid. EI mass spectra revealed a fragmentation path specific to this compound and in existent in lumiflavin or other similar compounds, due to ejection of a C2H5-N=C=O molecule, containing the ethyl substituent of the parent molecule.

Rate and Equilibrium in Aqueous 1:2 Chelation of Copper(II) by 2-Pyridinecarboxylic Acid Hydrazide. Antituberculosis Activity

Hernando J., Blanco C. A., Caballero I., Prieto T.

Polish Journal of Chemistry

2002

Vol. 76 / nr 12

1673-1680

Chelation reactions of 2-pyridinecarboxylic acid hydrazide, widely used drug in antituberculous regimens, with copper(II) have been investigated in aqueous solution at a temperature of 25_C. The ionization equilibria of the ligand and the stability of the metal-ligand complexes have also been characterized. Kinetic results show that the rate constant for monochelated complex formation is several times larger than the rate constant for dichelated complex formation. Adetailed mechanism is proposed to account for the kinetic data.