【摘要】 本文报道了三种具有Lindqvist结构的还原杂多阴离子ESR谱,在室温和适合的pH范围内,VMo₅O₁₉^4-的溶液ESR谱含有8条超精细线而V₂W₄O₁₉^5-和V₃W₃O₁₉^6-则具有15条超精细线,这种15条谱线的形状会逐渐变化。长期放置后它会变成8条线,我们用计算机成功地模拟了这些复杂的8+15条谱线,得到了一系列不同8线和15线比例的模拟谱。文中也测定了77K冷冻谱的ESR参数并计算了近似的K、α值,把所得的结果与Keggin结构杂多阴离子的K、α值进行比较后发现:Keggin结构的K,α值较小,原因是Keggin结构中存在有角共享的氧原子增加了未偶电子的额外离域性。更多还原

【Abstract】 The ESR spectra of three reduced heteropolyanions belonging to Lindqvist structure are reported in this paper. At room temperature and appropriate pH range the ESR spectrum of VMo5O194- contains 8 hyperfine lines and the spectra of V2W4O195- and V3W3O196-contain 15 hyperfines lines. These 15 lines gradually change their shape and finally become a eight-line spectrum after a longer period of time. We have successively simulated these complex 8 + 15 spectral lines by superposition of the 8 line with 15 line spectrum at different ratios. The ESR parameters of 77K frozen spectra are determined and the approximate K, a values are calculated based on LCAO-MO theory. The results are compared with those of Keggin structure polyanions. It is found that the K, a values of Keggin structure are smaller due to the extra delocalization originated from the additional corner-shared oxygen presented in the Keggin strcture.更多还原