Polarographic investigations

Comparative polarographic investigations show a significant difference in the polarographic behavior of cotarnine and that of N-methylcotarnine. The polarographically active form of cotarnine is the cotarninium ion, even in strongly alkaline solution,... 

Stability constants of metal complexes of 9-hydroxy-4//-pyrido[l,2-n]pyrimidin-4-one [Ni(II), Co(II), Zn(II), and Cd(II)] were determined by potentiometric and polarographic investigations (93JCC283). The distribution coefficient of risperidone (11) in H20- -octanol at pH 7.4 (log D — 2.04) was determined by an RP-HPLC method (01JMC2490). 

The role of the pH of the medium in the electrode reactions of organic compounds in aqueous solutions is well understood and has been recently reviewed in detail (Zuman, 1969). In particular, our understanding of this parameter is due to the large number of polarographic investigations where it has been found that the half-wave potential, the limiting current and the shape of the wave for an oxidation or reduction process may all be dependent on the acidity of the medium. 

As a result of polarographic investigations using e.g. a dropping mercury electrode electrochemical rate constants at the half wave potential Ey2 are reported ... 

Molten carbamide is known to be a good solvent for the salts of many metals [1] and was used as a supporting electrolyte in polarographic investigations both at a dropping mercury electrode and at a stationary... 

Electrocatalysis takes place during the first step of 02 reduction, H202 being formed in a two-electron step. The correctness of this assumption is supported by polarographic investigations of 02 reduction in the presence of phthalo-cyanines 49h... 

Dumanovic with colleagues carried out polarographic investigation of various derivatives 3-, 5-nitropyrazoles and 2-, 4-, 5-nitroimidazoles in aqueous buffer solutions (pH 1.8-9.3) and 0.1 M solution NaOH [903-912], On polarograms all the investigated nitroazoles have one or two waves of reduction both in acid and neutral medium. The first four-electron wave corresponds to reduction of nitro group to hydroxylamine one. The second two-electron wave corresponds to further reduction of hydroxylamine derivative to aminoazole (Scheme 3.34). 

The results from polarographic investigation may be found in the literature, where a reproduction of the experimental curves (e.g., Fig. 10, p. 308), a graphical plot of the half-wave potentials and the limiting currents as a function of pH (e.g., Figs. 2 and 3), or a table gives the required data. Reviews of polarographic papers appear every second year.37-39... 

Reibel (20j 21) has investigated the polarography of some polynuclear ammines in connection with polarographic investigations of the peroxo-bridged complexes. He found a single stage, three-electron reduction to Co" 2 for the polynuclear complexes. 

The polarographic investigation of the decomposition products of some benzodiazepines is also possible in acid solutions, the benzodiazepine ring is opened with formation of the corresponding substituted benzophenones, the polarographic behaviour of which is characteristic [224] Scheme 7). The decomposition product of oxazepam (3) on... 

Sher, A. Veber, M. Marolt-Gomiscek, M. Spectroscopic and polarographic investigations copper(II)-penicillin derivatives. Int. J. Pharm. 1997, 148, 191-199. 

A polarographic investigation of trichloronitromethane [42] shows a stepwise removal of chlorine under these conditions before the reduction of the nitro group occurs. Whether the difference in reduction path reflects the difference in the electrode material, electrode potential, or medium is not known. 

Imidic esters are easily hydrolyzed in aqueous solution, but some are stable enough for a polarographic investigation in a cold solution. Reduction at a lead cathode in cold 1 M sulfuric acid of ethyl benzimidate gave benzylamine in 76% yield [43]. The reduction can probably be described by ... 

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