Visible Light Spectroscopic Analysis of Methylene Blue in Water; What Comes after Dimer?
Visible Light Spectroscopic Analysis of Methylene Blue in Water; What Comes after Dimer?
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DOI：
10.1021/acsomega.0c03830
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发表时间：
2020-11-24
期刊：
影响因子：
4.1
通讯作者：
Marbán G
中科院分区：
文献类型：
--
作者：
Fernández-Pérez A;Marbán G
在我们以前的工作中，大多数试图研究亚甲基蓝（MB）在水中的自聚集已限于二聚体。在目前的工作中，我们已经分析了自聚集MB在水中超越二聚体形式。为此，大量MB水溶液的可见光吸收光谱（1.1 × 10-6至3.4 × 10-3 M）和NaCl（0.0-0.15 M）在不同温度下（282-333 K）已经被送入数学程序，以确定一个独特的更高的潜在存在，有序聚集体，而不对聚集体的有序性或需要抗衡离子（如氯离子）来补偿聚集体的正电荷有任何偏见。与通常认为三聚体是高MB浓度下的主要聚集体相反，令我们惊讶的是，我们发现单独作用的四聚体，并且没有任何反式，是产生所有实验吸收光谱的最佳拟合的高阶聚集体，具有非常低的平均相对误差0.04 ± 0.34%。同样与先前的假设相反的是，很明显，当甲基溴浓度低于3.4 × 10-5 M（11 ppm）时，溶液中存在这种聚集体，尽管程度相当低。这带来了需要重新计算的可见光吸收光谱和热力学参数的二聚体，这沿着与那些为四聚体是本工作的主要贡献。
As in our previous work, most attempts to study the self-aggregation of methylene blue (MB) in water have been limited to the dimer. In the present work, we have analyzed the self-aggregation of MB in water beyond the dimeric form. For this purpose, the visible light absorption spectra of a large number of aqueous solutions of MB (1.1 × 10–6 to 3.4 × 10–3 M) and NaCl (0.0–0.15 M) at different temperatures (282–333 K) have been fed to a mathematical routine in order to determine the potential existence of a unique higher-order aggregate without any preconception about the aggregation order or about the need of counterions, such as chloride, for compensating the positive charge of the aggregates. Contrary to the common belief that the trimer is the dominant aggregate at high MB concentration, to our surprise we found that the tetramer acting alone, and without any counterion, is the higher-order aggregate that yields the best fitting to all the experimental absorbance spectra, with a very low average relative error of 0.04 ± 0.34%. Also contrary to previous assumptions, it has emerged quite evidently that this aggregate is present in the solution at MB concentrations below 3.4 × 10–5 M (11 ppm), though to a rather low extent. This has brought the need for the recalculation of the visible light absorption spectrum and the thermodynamic parameters for the dimer, which along with those for the tetramer are the main contributions of the present work.
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影响因子：
--
作者：
Mondal, Suman B.;Gao, Shengkui;Zhu, Nan;Liang, Rongguang;Gruev, Viktor;Achilefu, Samuel
通讯作者：
Achilefu, Samuel
影响因子：
--
作者：
BERGMANN, K;OKONSKI, CT
通讯作者：
OKONSKI, CT
DOI：
10.1016/0020-711x(75)90007-5
发表时间：
1975-01-01
期刊：
INTERNATIONAL JOURNAL OF BIOCHEMISTRY
影响因子：
--
作者：
CAFFREY, M;KINSELLA, JE
通讯作者：
KINSELLA, JE
影响因子：
--
作者：
HILLSON, PJ;MCKAY, RB
通讯作者：
MCKAY, RB
影响因子：
22.1
作者：
Mills, Andrew
通讯作者：
Mills, Andrew