Cvjetan Nemanja, Kissner Reinhard, Bajuk-Bogdanović Danica, Ćirić-Marjanović Gordana, Walde Peter
Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich Vladimir-Prelog-Weg 5 8093 Zürich Switzerland
Department of Chemistry and Applied Biosciences, Laboratory of Inorganic Chemistry Vladimir-Prelog-Weg 2 8093 Zürich Switzerland.
RSC Adv. 2022 May 3;12(21):13154-13167. doi: 10.1039/d2ra02198f. eCollection 2022 Apr 28.
In a previous report on the enzymatic synthesis of the conductive emeraldine salt form of polyaniline (PANI-ES) in aqueous solution using PADPA (-aminodiphenylamine) as monomer, horseradish peroxidase isoenzyme C (HRPC) was applied as a catalyst at pH = 4.3 with HO as a terminal oxidant. In that work, anionic vesicles were added to the reaction mixture for (i) guiding the reaction to obtain poly(PADPA) products that resemble PANI-ES, and for (ii) preventing product precipitation (known as the "template effect"). In the work now presented, instead of native HRPC, only its prosthetic group ferric heme (= hemin) was utilized as a catalyst, and micelles formed from SDBS (sodium dodecylbenzenesulfonate) served as templates. For the elaborated optimal reaction conditions, complementary UV/vis/NIR, EPR, and Raman spectroscopy measurements clearly showed that the reaction mixture obtained after completion of the reaction contained PANI-ES-like products as dominating species, very similar to the products formed with HRPC as catalyst. HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonate) was found to have a positive effect on the reaction rate as compared to dihydrogenphosphate. This work is the first on the template-assisted formation of PANI-ES type products under mild, environmentally friendly conditions using hemin as a cost-effective catalyst.
在之前一篇关于在水溶液中使用对氨基二苯胺（PADPA）作为单体酶促合成导电聚苯胺翡翠盐形式（PANI-ES）的报告中，辣根过氧化物酶同工酶C（HRPC）在pH = 4.3时作为催化剂，以过氧化氢（HO）作为终端氧化剂。在该工作中，将阴离子囊泡添加到反应混合物中，用于（i）引导反应以获得类似于PANI-ES的聚（PADPA）产物，以及用于（ii）防止产物沉淀（称为“模板效应”）。在目前展示的工作中，不是使用天然HRPC，而是仅使用其辅基铁血红素（= 血红素）作为催化剂，并且由十二烷基苯磺酸钠（SDBS）形成的胶束用作模板。对于精心优化的反应条件，互补的紫外/可见/近红外光谱、电子顺磁共振和拉曼光谱测量清楚地表明，反应完成后得到的反应混合物中含有以PANI-ES类产物为主导的物种，与以HRPC作为催化剂形成的产物非常相似。与磷酸二氢盐相比，发现4-(2-羟乙基)-1-哌嗪乙磺酸（HEPES）对反应速率有积极影响。这项工作是首次在温和、环境友好的条件下使用血红素作为经济高效的催化剂进行模板辅助形成PANI-ES型产物的研究。
