Silica-bound copper(II) triazacyclononane as a phosphate esterase: effect of linker length and surface hydrophobicity
Silica-bound copper(II) triazacyclononane as a phosphate esterase: effect of linker length and surface hydrophobicity
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DOI：
10.1039/b811398j
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发表时间：
2009-01-01
影响因子：
4
通讯作者：
Burstyn, Judith N.
中科院分区：
文献类型：
--
作者：
Bodsgard, Brett R.;Clark, Robert W.;Burstyn, Judith N.
制备了一系列二氧化硅结合的三氮杂环壬烷铜（II）材料，以研究连接基长度和表面疏水性对磷酸酯水解的影响。这些非均相试剂的一般合成方法是在烯基改性的三氮杂环壬烷和氢化物改性的二氧化硅之间进行铑催化的硅氢化反应，然后用 Cu(II) 盐进行金属化。元素分析证实硅胶的有机官能化是成功的，并提供了三氮杂环壬烷表面浓度的估计。 EPR 光谱与方锥体 Cu(II) 一致，表明 Cu(II) 离子与固定大环化合物结合。使用双（对硝基苯基）磷酸酯（BNPP）和二乙基 4-硝基苯基磷酸酯（对氧磷）测试了这些异质试剂的水解功效。表现最好的试剂是辛基连接的丙醇封闭材料。这种材料具有最亲水的表面和最容易接近的活性位点，可达到与其他材料相同的最大速率，但循环次数较少且没有诱导期。
A series of silica-bound Cu(II) triazacyclononane materials was prepared to study the effect of linker length and surface hydrophobicity on the hydrolysis of phosphate esters. The general synthetic approach for these heterogeneous reagents was rhodium-catalyzed hydrosilation between an alkenyl-modified triazacyclononane and hydride-modified silica followed by metallation with a Cu(II) salt. Elemental analysis confirmed that organic functionalization of the silica gel was successful and provided an estimate of the surface concentration of triazacyclononane. EPR spectra were consistent with square pyramidal Cu(II), indicating that Cu(II) ions were bound to the immobilized macrocycles. The hydrolytic efficacies of these heterogeneous reagents were tested with bis(p-nitrophenyl) phosphate (BNPP) and diethyl 4-nitrophenyl phosphate (paraoxon). The agent that performed best was an octyl-linked, propanol-blocked material. This material had the most hydrophilic surface and the most accessible active site, achieving a rate maximum on par with the other materials, but in fewer cycles and without an induction period.