有机阳离子十聚钨酸盐的循环伏安研究

Cyclic Voltammetry Investigation of Decatungstate Anion W_(10)O_(32)^(4-) Combined with Organic Cations

用循环伏安法(CV)研究了3种不同有机阳离子的十聚钨酸盐(Q4W10O32,Q=C12H25(CH3)3N+、C14H29(CH3)3N+、C16H33(CH3)3N+)在DMF溶液中的电化学性质,并用量子化学的计算结果进行了讨论,同时讨论了有机阳离子的大小对十聚钨酸阴离子电化学性质的影响。结果表明:这3种十聚钨酸盐的CV均显示两对还原-氧化峰,其还原峰电位分别为:-0.976,-1.428,-0.980,-1.441和-1.008,-1.472 V。其中以C12H25(CH3)3N+、C14H29(CH3)3N+为反荷离子的十聚钨酸盐,其第一对还原-氧化峰具有可逆的性质,由此测得它们在DMF中的扩散系数分别为:3.83×10-7,3.80×10-7cm2/s。有机阳离子的大小对W10O342-的还原-氧化电位有明显的影响,随着碳链的增大,还原峰电位向负移。

The electrochemical properties of decatungstate anion W10O32^4- combined respectively with three kinds of organic cations Q （ Q = C12 H25 （ CH3 ）3N^＋ , C14 H29 （ CH3 ）3N^＋ , C16 H33 （ CH3 ）3N^＋ ） were researched by means of cyclic voltammetry in the solution of DMF containing supporting electrolyte 0. 1 moL/L tetrabutyl ammonium bromide （Bu4NBr） and discussed according to the theoretic results calculated by quantum chemistry. The influences of variable cation volume on the electrochemical properties of W10O32^4- have also been made clear. The experiments indicated that two pairs of redox waves were observed on the cyclic vohammograms for three kinds of decatungstate salts. The first redox wave of W10O32^4- combined respectively with C12 and C14 is reversible and their diffusion coefficients in DMF were valuated as 3.83 × 10^-7 cm^2/s and 3.80 × 10^-7 cm^2/s, respectively. The volume of organic cations has an obvious influence on the redox potentials of decatungstate anion, as a result that the peak potential of reduction shifts to more negative position with increasing of cation volume.