Determination of palladium and phosphorus in biologically active palladium(II) complexes of aminophosphonic acid derivatives

摘要

Due to its widespread occurrence in nature, phosphorus compounds both as inorganic and organic bond species, play an important role in various compartments of the environment. Organophosphorus compounds, especially derivatives of phosphonic and aminophosphonic acids, are of significant importance in metabolism and some biological processes. Their biological activity is mainly displayed through metabolic regulation and inhibition of various metalloenzymes having an amino acid as a substrate. Numerous applications from medicine to agriculture as antibiotic, antitumor, herbicidal and fungicidal agents have been found for these compounds. Another interesting aspect regarding this kind of compounds arises from their ability of forming various types of neutral and ionic metal complexes, which might be also of interest due to their biological activity. Some aminophosphonate complexes of platinum(II) and palladium(II) have shown significant antitumor activity. Our interest in this field has been directed to palladium(II) complexes of quinoline- and aniline-based phosphonates. The object of the present research was to develop an efficient procedure for mineralization of various types of these biologically active complexes as well as to develop the method that was compatible with determination of palladium and phosphorus in these compounds. The first step in chemical analysis is a proper preparation of the investigated samples, in particular elimination of organic matter, which is commonly carried out by careful acid digestion. This procedure depends on the type of complex and it is different for molecular adducts as well as for various metallocyclic and ionic palladium complexes. Palladium was separated and determined by a gravimetry with 1,2-cyclohexanedione dioxime (nioxime), while the vanadomolybdatophosphoric acid spectrophotometric method was applied for the subsequent determination of phosphorus. Possible interference caused by the use of an excess of nioxime has been studied.