Potentiometric study of azide complexes of copper(II) in aqueous medium

✍ Scribed by J.F. de Andrade; O.M. Guimarães

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 404 KB
• Volume: 271
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(93)80562-y

✦ Synopsis

The stepwlse fonnatlon of copper(B)-azlde complexes m aqueous sodmm perchlorate medmm was mvestlgated at 25 0 f 0 1°C and lomc strength 1 0 M With the mdlrect potentlometrlc method employed, usmg a glass electrode and under the condltlons studled, four mononuclear complexes were detected No evidence of polynuclear species was found The final analysis of the data, by solution of simultaneous equations (matrur method), led to the followmg overall formatlon constants PI = 2 44 x IO* I mol-', & = 120 X lo4 I2 mol-*, & = 145 X 10' I3 molm3 and pq = 3 18 x 10' I4 molw4 The graphlcal method of Leden, with some refinements, was also utked mltlally Keywords Potentlometry, Azlde complexes, Copper A contmumg, systematic mvestlgatlon of azlde complexes, with several metalhc catlons, has been made m order to obtain data on their coordmatlon chemistry [l-5] and to develop analytical apphcatlons [6-81 As part of these mvestlgatlons, this paper reports a competltlve and indirect potentlometrlc study of the copper(azlde system with the use of a glass electrode and pH measurements on solutions contammg different copper(H) concentrations and azlde-hydrazolc acid buffers All measurements were made m aqueous medium at 25 0°C and ionic strength 10 M (sodium perchlorate)

The reaction m acidified medmm between azlde and copper(H) has previously been used spectrophotometrlcally to determine the metal 18-121 and the hgand [6,13] and to establish equlhbrmm constants [2,14-161 In such equlhbrmm studies, prmclpally the first stab&y constant was determined