Журнал "Макрогетероциклы"

Maria N. Malinkina,^а Anna S. Makarova,^b Sergei V. Makarov,^a@ and Denis S. Salnikov^а

^aResearch Institute of Macroheterocyclic Compounds, Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Russia

^bInstitute of Solution Chemistry of RAS, 153045 Ivanovo, Russia

^@Corresponding author E-mail: makarov@isuct.ru

DOI: 10.6060/mhc2011.1.09

The kinetics of reaction between monosaccharides and cobalt tetrasulfophthalocyanine was studied spectrophotometrically. The reaction is shown to proceed with measurable rates only in strongly alkaline solutions. A product of reaction is determined to be CoI phthalocyanine (CoI(TSPc)^5-). The reducing ability of monosaccharides decreases in following sequence: xylose > fructose > ribose > glucose. The main factor influencing on their reducing ability is shown to be ratio between furanose and open forms of monosaccharide. The results of this work allow to recommend using of monosaccharides in studies of reduced metal phthalocyanines and other tetrapyrrolic complexes. Indeed, to receive “pure” kinetics of their oxidation the reductant should not reduce oxidized complex again, i.e. redox cycle should not proceed. It is shown that this prerequisite is working in the case of glucose (reductant of CoII(TSPc)^4-) and nitrite (oxidant of CoI(TSPc)^5-). In contrast to reduction of CoII(TSPc)^4- by glucose, oxidation of CoI(TSPc)^5- by nitrite proceeds in weakly alkaline and neutral solutions. Therefore the reverse process does not interfere with oxidation of CoI(TSPc)^5-.

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