have been evaluated by choosing suitable pH regions. An additional protonation of the nickel(IV) complexes (pKa= 4.91 and 4.28 respectively) has been encountered and a realistic interpretation is achieved by considering a weak acid–base interaction arising out of outer-sphere protonation of the [NiIV(Lx)]2+ complexes. All the reaction steps have been scrutinised. The reduction [NiIV(Lx)]2+→[NiIII(Lx)]+
[Ni IV L 3 2 ] 2+和[Ni IV L 2 ] 2+(HL 3 = 6-
氨基-3-甲基-4-azahex-3-en-2-one
肟,H 2 L 2 = 3,14-二甲基-4,7,10,13-四氮杂
十六烷-3,13-二烯-2,15-二酮二
肟)在伪一阶条件下用分光光度法研究,过量pH 2.50–8.0范围内的
硫代
硫酸盐,[Ni IV ] = 5.0×10 –5 mol dm –3,[S 2 O 3 2– ] =(1.0–10.0)×10 –3 mol dm –3,在20°C时I = 0.20 mol dm –3(NaClO 4)。在3.0⩽pH⩽5.0和2.5⩽pH⩽4.0区域发现了单相两电子转移,分别还原了两种络合物。这些pH区域上方两个反应表明双相衰变具有初始更快步骤的Ni IV →
镍III和第二较慢步骤的Ni III →
镍II,和一般速率定律是-d [
镍IV(L X)2+ ]