|Hyphenated techniques in the study of inorganic complexes in solution
|Exploiting Separation Science
|Prof Olga Shuvaeva
|Institute of Inorganic Chemistry
Abstract Information :
It is known that the chemistry of complex compounds is one of the fastest growing areas of modern inorganic chemistry. Among them are polyoxometalates (POM) as well as of polynuclear complexes (PNC) These substances are widely used in many areas of modern science as catalysts, and besides that in pharmacology and medicine, in the fields of micro- and nanotechnology, etc. However, fairly typical situation when, in the course of their synthesis, the mixture of the products is formed, wherein the solids phase and solution are substantially different.
In this way there are a number of the problems in the study of such compounds: firstly, the presence of different equilibrium chemical forms for each component.; secondly, their limited stability which complicates the choice of separation conditions; and the third - similarity in composition and structure of this type of complexes often appears in resembling UV-VIS absorption spectra, creating difficulties for identification. Finally, the lack of individual compounds also complicates the identification of speciation patterns. The observation of such processes requires special direct techniques and approaches, so the data interpretation is obstructed.
In frame of the present work the separation possibilities of POM on the base of different elements (P, Mo, V, Nb, W, Te and others) and the mono- and polynuclear complexes of Rhodium with the similar structure and composition using HPLC-ICP-AES were estimated. The data obtained are in consistent with other techniques: capillary electrophoresis, UV-VIS absorption and NMR spectroscopy. Thus, the approaches for the study of the mixtures formed in self-assembly reactions of POM and in the process of rhodium polynuclear forms generation were developed.
It was shown that capillary electrophoresis and HPLC may be successfully applied for the study of the state of inorganic complexes in solution. However, the most appropriate approach for the study of these compounds is the combination of methods and techniques such as HPLC, CE and spectroscopic methods such as UV-VIS, NMR et al.