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本文报道了五种具有Keggin结构的还原杂多阴离子的溶液和-150℃冷冻ESR谱,它们是SiV_2Mo_(10)O_(40)~(6-)、SiV_3Mo_9O_(40)~(6-)、PV_3Mo_9O_(40)~(6-)、PV_3W_9O_(40)~(6-)和VV_3W_9O_(40)~(6-)。在室温下pH≤3时,所有杂多酸阴离子均为8条锐线,pH=7-8时,均为8+15条线并且随着放置时间增长逐步变成8条线。在-150℃时均呈现出V~(4+)8条线的复杂粉末谱,作者根据一种修正的Ble-aney方法成功地模拟了这些冷冻谱,得出g_(‖)、g_(⊥)、A_(‖)、A_(⊥),按照DeArmond理论计算了近似的K、α值并讨论了它们的物理意义。最后从异构体的数目和简并度的观点初步解释了观察不到V_3物种22条超精细线的原因。
In this paper, five solutions of heteropolyanion with Keggin structure and ESR spectra at -150 ℃ were reported. They are SiV_2Mo_ (10) O_ (40) ~ (6), SiV_3Mo_9O_ (40) ~ (6), PV_3Mo_9O_ (40) ~ (6 -), PV_3W_9O_ (40) ~ (6-) and VV_3W_9O_ (40) ~ (6-). When pH≤3 at room temperature, all the heteropolyacid anions are 8 sharp lines, which are 8 + 15 lines at pH = 7-8, and gradually become 8 lines as the standing time increases. The complex powder spectra of 8 lines of V ~ (4 +) were all found at -150 ℃. The authors successfully simulated these frozen spectra according to a modified Ble-aney method and obtained the results of g_ (∥), g_ (⊥ ), A_ (∥) and A_ (⊥). According to the DeArmond theory, the approximate K, α values are calculated and their physical meanings are discussed. Finally, the reason why no 22 hyperfine lines of V_3 species can be observed was initially explained from the perspective of the number of isomers and degeneracy.