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金属有机框架载体内Ru(bda)L_(2)催化剂微环境的调控实现高效光驱动水氧化
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作者 冯坚信 李轩 +4 位作者 罗宇成 苏志芳 钟茂灵 余宝蓝 石建英 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第5期127-136,共10页
人工光合作用研究中,因涉及多个电子和质子的转移而具有缓慢动力学特征的产氧半反应,是实现水全分解的关键.作为一类高效水氧化催化剂,Ru(bda)L_(2)(H_(2)bda=2,2’-联吡啶-6,6’-二羧酸,L=配体)分子催化剂被广泛应用于化学驱动的水氧... 人工光合作用研究中,因涉及多个电子和质子的转移而具有缓慢动力学特征的产氧半反应,是实现水全分解的关键.作为一类高效水氧化催化剂,Ru(bda)L_(2)(H_(2)bda=2,2’-联吡啶-6,6’-二羧酸,L=配体)分子催化剂被广泛应用于化学驱动的水氧化研究,其中O-O键的形成是水氧化反应的决速步骤.相比之下,因光敏剂和牺牲试剂的参与,光驱动水氧化反应的决速步骤为高价Ru物种的形成,且存在光敏剂自身氧化分解与光敏剂氧化催化中心成为高价Ru物种之间的竞争.因此,促进分子催化剂向光敏剂的多步非等价电子转移,是提高光催化水氧化性能的关键.自然光合作用中,水氧化过程中高效的质子传输和电子转移与光系统PSII中[Mn_(4)CaO_(5)]簇活性位点周围复杂的蛋白质微环境密切相关.因此,利用多孔载体实现Ru分子催化剂的固载,在多相化提高其稳定性的同时,为Ru催化剂周围微环境的调控提供了可能.基于本课题组前期发展的配位辅助自组装策略,本文将Ru(bda)L_(2)分子催化剂固载到金属-有机框架UiO-66载体中(Ru(bda)L_(2)@UiO-66),作为孤立的催化位点用于化学驱动和光驱动水氧化反应研究.在Ce^(4+)化学驱动水氧化反应中,Ru(bda)L_(2)@UiO-66表现出比均相体系更高的活性和稳定性.在以Ru(bpy)_(3)Cl_(2)为光敏剂,Na_(2)S_(2)O_(8)为牺牲剂的光催化体系,Ru(bda)L_(2)@UiO-66在磷酸盐缓冲水溶液中光驱动水氧化催化转化数高达566,比相同条件下的均相催化剂高出近20倍.进一步对比磷酸盐缓冲水溶液、硼酸盐缓冲水溶液和纯水三种溶剂中的光驱动水氧化性能,发现水氧化性能越高,因光敏剂氧化分解而产生的CO_(2)量越低.通过紫外-可见漫反射光谱、红外光谱、X射线粉末衍射和X射线光电子能谱等技术对反应前后催化剂的组成和结构进行研究,结果表明,在化学驱动水氧化反应前后Ru(bda)L_(2)@UiO-66结构保持不变;而光驱动水氧化反应中,高的产氧性能伴随着UiO-66骨架结构在高浓度硫酸盐存在下的逐步坍塌.动力学同位素效应(KIE)揭示了水氧化过程中存在质子参与.质子库存实验与氢核磁证实,在光催化过程中载体因磷酸盐的摄入而在催化剂周边构建了含水的氢键网络.结合水氧化亲核进攻反应机制中质子的参与以及可能的质子耦合电子转移,提出载体摄入的磷酸盐作为质子中继体与水分子的氢键网络相耦合,促进了光驱动水分解产氧性能,同时抑制了与之相竞争的光敏剂的氧化分解机理.综上,本工作提供了一种运用多相化载体来模拟催化剂类酶微环境的思路,对于实现高效人工光合作用具有一定参考价值. 展开更多
关键词 Ru(bda)L_(2)催化剂 隔离位点 光驱动水氧化 质子介质 微环境
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Evolutionary divergence of subgenomes in common carp provides insights into speciation and allopolyploid success
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作者 Lin Chen Chengyu Li +13 位作者 Bijun Li Xiaofan Zhou Yulin Bai Xiaoqing Zou Zhixiong Zhou Qian He Baohua Chen Mei Wang Yaguo Xue Zhou Jiang jianxin feng Tao Zhou Zhanjiang Liu Peng Xu 《Fundamental Research》 CAS CSCD 2024年第3期589-602,共14页
Hybridization and polyploidization have made great contributions to speciation,heterosis,and agricultural production within plants,but there is still limited understanding and utilization in animals.Subgenome structur... Hybridization and polyploidization have made great contributions to speciation,heterosis,and agricultural production within plants,but there is still limited understanding and utilization in animals.Subgenome structure and expression reorganization and cooperation post hybridization and polyploidization are essential for speciation and allopolyploid success.However,the mechanisms have not yet been comprehensively assessed in animals.Here,we produced a high-fidelity reference genome sequence for common carp,a typical allotetraploid fish species cultured worldwide.This genome enabled in-depth analysis of the evolution of subgenome architecture and expression responses.Most genes were expressed with subgenome biases,with a trend of transition from the expression of subgenome A during the early stages to that of subgenome B during the late stages of embryonic development.While subgenome A evolved more rapidly,subgenome B contributed to a greater level of expression during development and under stressful conditions.Stable dominant patterns for homoeologous gene pairs both during development and under thermal stress suggest a potential fixed heterosis in the allotetraploid genome.Preferentially expressing either copy of a homoeologous gene at higher levels to confer development and response to stress indicates the dominant effect of heterosis.The plasticity of subgenomes and their shifting of dominant expression during early development,and in response to stressful conditions,provide novel insights into the molecular basis of the successful speciation,evolution,and heterosis of the allotetraploid common carp. 展开更多
关键词 Allotetraploid Subgenome structural evolution Homoeologous expression Expression dominance shift Environmental adaptation
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