51V-NMR investigation on the formation of peroxo vanadium complexes in aqueous solution: Some novel observations

Q4 Chemical Engineering
Valeria Conte, Fulvio Di Furia, Stefano Moro
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引用次数: 51

Abstract

Depending on the experimental conditions either monoperoxo or diperoxo vanadium complexes are formed in acid aqueous solutions by addition of H2O2 to NH4VO3. The 51V-NMR spectra of both species have been registered at different pH values. While the signal of the monoperoxo derivative is unchanged in the pH range 0–4, the chemical shift of the diperoxo species shows a continuous variation in the same interval thus suggesting the occurrence of a protonation equilibrium leading to a neutral diperoxo vanadium complex. In the presence of bidentate ligands L, e.g., picolinic or pyrazinic acid, under otherwise identical experimental conditions, complexed peroxo vanadium species are formed. The association equilibria can be conveniently studied by 51V-NMR spectroscopy. Thus, different species, e.g., VO(O2)L, [VO(O2)L2], [VO(O2)2L]2− as a function of the pH has been detected and the corresponding association constants have been measured.

水溶液中过氧钒配合物形成的51V-NMR研究:一些新观察
根据实验条件的不同,在酸性水溶液中,通过将H2O2加入到NH4VO3中可以形成一过氧或二过氧钒配合物。在不同的pH值下,两种物质的51V-NMR谱被记录下来。在pH值0 ~ 4范围内,单过氧衍生物的信号没有变化,而双过氧衍生物的化学位移在同一区间内呈连续变化,这表明质子化平衡的发生导致了中性的双过氧钒配合物。在双齿配体L的存在下,如吡啶酸或吡嗪酸,在其他相同的实验条件下,形成络合的过氧钒。用51V-NMR谱法可以方便地研究缔合平衡。因此,不同的物种,如VO(O2)L, [VO(O2)L2]−,[VO(O2)2L]2−作为pH的函数已经被检测到,并测量了相应的缔合常数。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
分子催化
分子催化 Chemical Engineering-Catalysis
CiteScore
1.50
自引率
0.00%
发文量
2959
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