Solar energy driven C–C bond cleavage in a lignin model compound with a D–π–A organic dye-sensitized photoanode
Solar energy driven C–C bond cleavage in a lignin model compound with a D–π–A organic dye-sensitized photoanode
复制标题
太阳能驱动的木质素模型化合物中的 C–C 键断裂，具有 D–––A 有机染料敏化光电阳极
DOI：
10.1039/d3se00194f
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发表时间：
2023
影响因子：
5.6
通讯作者：
Lee, Jae-Joon
中科院分区：
文献类型：
--
作者：
Kim, Saerona;Kang, Hyeong Cheol;Chu, Chun;Li, Shuya;Yoo, Kicheon;Wijethunga, Udani Kaushalya;Zheng, Weiwei;Yoo, Chang Geun;Sherman, Benjamin D.;Lee, Jae-Joon
C-C σ-键的高键离解能对有机合成、聚合物降解和生物质转化中的化学转化提出了挑战，这些化学转化需要在室温下化学选择性地裂解C-C键。结合分子有机染料的染料敏化光电化学电池（DSPECs）可以提供一种使用可再生太阳能来驱动这些类型的能量要求高的化学选择性C-C键裂解反应的方法。本研究报道了在室温下使用基于供体-π-共轭桥-受体（D-π-A）有机染料的DSPEC系统，在太阳光驱动下活化双环氨氧基介体以实现木质素模型化合物（LMC）的芳基醚键中的C-C键断裂。研究了沿着双环氨基氧自由基介体（9-氮杂双环[3，3，1]壬-3-酮-9-氧自由基，KABNO）和5-[4-（二苯基氨基）苯基]噻吩-2-氰基丙烯酸（DPTC）D-π-A有机染料修饰的介孔TiO 2光阳极表面在有和无LMC存在下的溶液中的变化.对KABNO的DPTC的光物理研究表明，在1个太阳照射下（100 mW cm−2），分子间的能量/电子转移。在光照下，D-π-A型DPTC敏化的TiO 2光阳极促进反应性氧代铵物种KABNO+作为强氧化剂的产生，这是驱动LMC的氧化C-C键断裂所需的。在完全DSPEC体系中，KABNO的光电化学氧化反应生成了C-C键断裂产物2-（2-甲氧基苯氧基）丙烯醛（94%）和2，6-二甲氧基-1，4-苯醌（66%）。该方法提供了第一份报告，利用D-π-A型有机染料与双环硝酰基自由基介体的组合，在室温下对C-C σ-键进行非均相光电解氧化裂解，模拟在木质素中发现的那些。
The high bond dissociation energy of C–C σ-bonds presents a challenge to chemical conversions in organic synthesis, polymer degradation, and biomass conversion that require chemoselective C–C bond cleavage at room temperature. Dye-sensitized photoelectrochemical cells (DSPECs) incorporating molecular organic dyes could offer a means of using renewable solar energy to drive these types of energetically demanding chemoselective C–C bond cleavage reactions. This study reports the solar light-driven activation of a bicyclic aminoxyl mediator to achieve C–C bond cleavage in the aryl-ether linkage of a lignin model compound (LMC) at room temperature using a donor–π-conjugated bridge–acceptor (D–π–A) organic dye-based DSPEC system. Mesoporous TiO2 photoanode surfaces modified with 5-[4-(diphenylamino)phenyl]thiophene-2-cyanoacrylic acid (DPTC) D–π–A organic dye were investigated along with a bicyclic aminoxyl radical mediator (9-azabicyclo[3,3,1]nonan-3-one-9-oxyl, KABNO) in solution with and without the presence of LMC. Photophysical studies of DPTC with KABNO showed intermolecular energy/electron transfer under 1 sun illumination (100 mW cm−2). Under illumination, the D–π–A type DPTC sensitized TiO2 photoanodes facilitate the generation of the reactive oxoammonium species KABNO+ as a strong oxidizing agent, which is required to drive the oxidative C–C bond cleavage of LMC. The photoelectrochemical oxidative reaction in a complete DSPEC with KABNO afforded C–C bond cleavage products 2-(2-methoxyphenoxy)acrylaldehyde (94%) and 2,6-dimethoxy-1,4-benzoquinone (66%). This process provides a first report utilizing a D–π–A type organic dye in combination with a bicyclic nitroxyl radical mediator for heterogeneous photoelectrolytic oxidative cleavage of C–C σ-bonds, modeled on those found in lignin, at room temperature.