The Mechanism of Formation of Active Fe-TAMLs Using HClO Enlightens Design for Maximizing Catalytic Activity at Environmentally Optimal, Circumneutral pH.
The Mechanism of Formation of Active Fe-TAMLs Using HClO Enlightens Design for Maximizing Catalytic Activity at Environmentally Optimal, Circumneutral pH.
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DOI：
10.1021/acs.inorgchem.3c00104
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发表时间：
2023-04-10
影响因子：
4.6
通讯作者：
Collins, Terrence J.
中科院分区：
文献类型：
--
作者：
Pal, Parameswar;Schafer, Marcus C.;Hendrich, Michael P.;Ryabov, Alexander D.;Collins, Terrence J.
Fe-TAML/过氧化物催化为去除水中的微污染物提供了简单，强大，超稀释的方法。H2 O2与Fe-TAMLs的典型速率决定相互作用（速率常数kI）对pH敏感，在pH 9-10窗口中具有速率最大值。Fe-TAML设计或将最大速率转移到大多数废水的pH 6-8窗口的工艺设计将使微污染物消除更加强大。在这里，我们展示了Fe-TAML与过氧化物或次氯酸盐相互作用的不同pH依赖性如何形成活性Fe-TAML（kI步骤），这说明了为什么从H2 O2（pKa，约1.5）移动到Fe-TAML（kI步骤）。11.6）到次氯酸盐（pKa，7.5）移动最快的催化pH值低至8.2。在pH 7时，次氯酸盐催化比H2 O2催化快100-1000倍。最大催化活性的pH也被Fe-TAML轴向水配体的pKa调节，对于[Fe{4-NO2 C6 H3 - 1，2-（NCOCMe2NSO2）2CHMe}（H2O）n]−（2）[n = 1-2]、[Fe{4-NO2C6H3- 1，2-（NCOCMe2NCO）2CF2}（H2O）n]−（1b）和[Fe{C6H4- 1，2-（NCOCMe2NCO）2CMe2}（H2O）n]−（1a）。新的双（磺酰氨基）-双（碳酰氨基）-连接的2表现出最低的pKa，并提供最大的次氯酸盐超过过氧化物的催化速率优势。快速的Fe-TAML/次氯酸盐催化伴随着缓慢的非催化氧化橙子II。TAML在碱性条件下被H2 O2活化得更快，在接近中性的pH下需要最有效的活化。后一个目标加上100 - 1000倍的反应性增益是通过使用次氯酸盐作为主要氧化剂实现的，因为其pKa值（7.5）低于H2 O2（11.5）。
Fe-TAML/peroxide catalysis provides simple, powerful, ultradilute approaches for removing micropollutants from water. The typically rate-determining interactions of H2O2 with Fe-TAMLs (rate constant kI) are sharply pH-sensitive with rate maxima in the pH 9–10 window. Fe-TAML design or process design that shifts the maximum rates to the pH 6–8 window of most wastewaters would make micropollutant eliminations even more powerful. Here, we show how the different pH dependencies of the interactions of Fe-TAMLs with peroxide or hypochlorite to form active Fe-TAMLs (kI step) illuminate why moving from H2O2 (pKa, ca. 11.6) to hypochlorite (pKa, 7.5) shifts the pH of the fastest catalysis to as low as 8.2. At pH 7, hypochlorite catalysis is 100–1000 times faster than H2O2 catalysis. The pH of maximum catalytic activity is also moderated by the pKa’s of the Fe-TAML axial water ligands, 8.8, 9.3, and 10.3, respectively, for [Fe{4-NO2C6H3-1,2-(NCOCMe2NSO2)2CHMe}(H2O)n]− (2) [n = 1–2], [Fe{4-NO2C6H3-1,2-(NCOCMe2NCO)2CF2}(H2O)n]− (1b), and [Fe{C6H4-1,2-(NCOCMe2NCO)2CMe2}(H2O)n]− (1a). The new bis(sulfonamido)-bis(carbonamido)-ligated 2 exhibits the lowest pKa and delivers the largest hypochlorite over peroxide catalytic rate advantage. The fast Fe-TAML/hypochlorite catalysis is accompanied by slow noncatalytic oxidations of Orange II. TAMLs are activated faster by H2O2 under basic conditions, and the most efficient activation is desired at near-neutral pH. The latter goal plus 100−1000-fold reactivity gain were achieved by using hypochlorite as a primary oxidant due to its lower pKa value (7.5) compared to that of H2O2 (11.5).
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影响因子：
5.8
作者：
Somasundar Y;Burton AE;Mills MR;Zhang DZ;Ryabov AD;Collins TJ
通讯作者：
Collins TJ
影响因子：
15
作者：
Ghosh, A;Ryabov, AD;Collins, TJ
通讯作者：
Collins, TJ
影响因子：
4.6
作者：
Mills, Matthew R.;Weitz, Andrew C.;Collins, Terrence J.
通讯作者：
Collins, Terrence J.
影响因子：
1.7
作者：
Emelianenko, Maria;Torrejon, Diego;Collins, Terrence J.
通讯作者：
Collins, Terrence J.
影响因子：
4.5
作者：
Oakes, J;Gratton, P;Gordon-Smith, T
通讯作者：
Gordon-Smith, T