“…13 These compounds exhibit different biological activity, in particular hypoglycemic, antimicrobial, fungicidal, antiviral, antiinflammatory, and antitumor. [14][15][16] In our previous studies, the physicochemical properties of the new reagents: 5-hydroxyimino-4-imino-1,3thiazo lidin-2-one (HITO), 4-[N'-(4-imino-2-oxo-thiazolidin-5-ylidene)-hydrazino]-benzenesulfonic acid and 1-(5-benzylthiazol-2-yl)azonaphthalen-2-ol, which belong to the class of azolidones, and the interaction of Pd(II), Rh(III), Pt(IV), Ir(IV), Cu(II), Zn(II), Cd(II), Ni(II), and Hg(II) ions with these reagents were investigated [17][18][19][20][21][22][23][24][25][26][27][28] and the methods of their determination with good metrological characteristics were proposed. [18][19][20][21][22][23][24][25]27,28 Therefore in this paper, we investigated the interaction of ruthenium(IV) ions with 5-hydroxyimino-4-imino-1,3-thiazolidin-2-one.…”