37473-63-5Relevant academic research and scientific papers
Chromium(II) and vanadium(II) reduction of pentacyanocobaltate(III) complexes
Balahura, Robert J.,Johnson, Michael D.
, p. 4548 - 4551 (2008/10/08)
The chromium(II) and vanadium(II) reductions of the pentacyanocobaltate(III) complexes of pyrazine (pyz), isonicotinamide (isn), 4-cyanopyridine (4-CN-py), and pyridine (py) have been studied. For chromium(II), the reductions are first order in Cr(II) and cobalt(III) complex and independent of hydrogen ion concentration. At 25°C, I = 1.0 M (LiClO4), kCr = 1.5 × 103, 19, 28, and 1.2 M-1 s-1 for pyz, isn, 4-CN-py, and py, respectively. A radical-ion mechanism is proposed for the reduction of the first three complexes. For V(II), two reactions are observed with rate laws kobs1 = k1[V2+] + k-1 and kobs2 = k[V2+]/(1 + K1[V2+]). The first reaction is the formation of a binuclear intermediate precursor complex bridged by a cyanide from the oxidant. Values of k1 (M-1 s-1), k-1 (s-1) for pyz, isn, 4-CN-py, py: 65, 1.1; 55, 1.0; 46, 1.2; 49, 1.0. The saturation type kinetics observed in the second reaction are consistent with formation of a precursor complex that is a dead end on the reduction pathway and a subsequent outer-sphere reduction between monomeric reactants.
