A Voltammetric Study of the Complexation of Copper by the Psychoactive Compounds 1,4-Benzodiazepines

✍ Scribed by M. M. Correia dos Santos; V. Famila; M. L. Simões Gonçalves

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 128 KB
• Volume: 12
• Category: Article
• ISSN: 1040-0397
• DOI: 10.1002/(sici)1521-4109(200002)12:3<216::aid-elan216>3.0.co;2-q

✦ Synopsis

Complexation of copper ions with the 1,4-benzodiazepines bromazepam, midazolam and chlordiazepoxide is investigated using voltammetric methods, mainly differential pulse polarography in KNO 3 0.10 M and pH 7.0 + 0.1. Additional evidence of the complexation of copper was obtained by an UV-spectrophotometric study. Reduction of the metal ion as well as that of the ligands followed and the voltammetric behavior was interpreted in terms of complex formation. Stability constants have been determined for the experimental conditions used and the values were compared with those from the spectrophotometric study. The results show that copper(II) complexation is favored by the presence of chelating groups other than the azomethine group common to all the 1,4-benzodiazepines. It is also apparent that in some circumstances copper in the +1 oxidation state may be stabilized by complex formation. This result could only be inferred from the voltammetric data since in the presence of appropriate ligands the copper(I) oxidation state is produced electrochemically at the electrode/solution interface. The processes studied may help in understanding some of the features of the binding mechanisms between copper ion and the 1,4-benzodiazepine derivatives.