Convenient and accurate insight into solution-phase equilibria from FlowNMR titrations
Convenient and accurate insight into solution-phase equilibria from FlowNMR titrations
复制标题
通过 FlowNMR 滴定方便、准确地了解溶液相平衡
DOI：
10.1039/d2re00123c
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发表时间：
2022
影响因子：
3.9
通讯作者：
Berry D
中科院分区：
文献类型：
--
作者：
Berry D
酸/碱反应和络合物形成等化学溶液相平衡通常通过滴定研究来研究，滴定研究要么使用测量单一属性（例如特定波长下的 pH 值或紫外可见吸光度）的技术对连续变化的样品进行原位分析，要么使用高分辨率技术（例如高场 NMR 光谱）对多个样品进行异位分析。在这里，我们提出多核高分辨率 FlowNMR 波谱作为在线分析复杂溶液相平衡的有效技术，它将简单原位测量的准确性和便利性与高分辨率 NMR 波谱的高特异性和信息内容结合起来。通过闭环流设置，可以使用简单的注射泵自动添加试剂，并且可以将免费传感器（例如 pH 探针和紫外可见流通池）添加到设置中。通过在与 FlowNMR 设置相连的手套箱内进行滴定，甚至可以研究对空气和湿度高度敏感的系统。该方法的有效性通过布朗斯台德酸/碱滴定（包括多组分混合物和有溶剂参与的系统）、氢键相互作用、路易斯酸/碱相互作用和动态金属-配体结合的例子得到证明。
Chemical solution-phase equilibria such as acid/base reactions and complex formation are typically investigated by titration studies that either use in situ analysis of a continuously changing sample with techniques that measure single attributes (e.g. pH or UV-vis absorbance at a specific wavelength) or ex situ analysis of multiple samples with high-resolution techniques (e.g. high field NMR spectroscopy). Here we present multi-nuclear high resolution FlowNMR spectroscopy as an effective technique for the online analysis of complex solution-phase equilibria that combines the accuracy and convenience of simple in situ measurements with the high specificity and information content of high-resolution NMR spectroscopy. With a closed-loop flow setup reagent addition can be automated using a simple syringe pump and complimentary sensors (such as pH probes and UV-vis flow cells) may be added to the setup. By conducting the titration inside a glovebox connected to the FlowNMR setup even highly air- and moisture-sensitive systems may be investigated. The effectiveness of this approach is demonstrated with examples of Brønsted acid/base titrations (incl. multi-component mixtures and systems with solvent participation), hydrogen bonding interactions, Lewis acid/base interactions, and dynamic metal–ligand binding.