The low-efficiency CO_(2) uptake capacity and insufficient photogenerated exciton dissociation of current metal halide perovskite(MHP)nanocrystals with end-capping ligands extremely restrict their application in the f...The low-efficiency CO_(2) uptake capacity and insufficient photogenerated exciton dissociation of current metal halide perovskite(MHP)nanocrystals with end-capping ligands extremely restrict their application in the field of artificial photosynthesis.Herein,we demonstrate that ligand-free CsPbBr_(3) with calliandralike nanostructure(LF-CPB CL)can be synthesized easily through a ligand-free seed-assisted dissolutionrecrystallization growth process,exhibiting significantly enhanced CO_(2) uptake capacity.More specifically,the abundant surface bromine(Br)vacancies in ligand-free MHP materials are demonstrated to be beneficial to photogenerated carrier separation.The electron consumption rate of LF-CPB CL for photocatalytic CO_(2) reduction increases 7 and 20 times over those of traditional ligand-capping CsPbBr_(3)nanocrystal(L-CPB NC)and bulk CsPbBr_(3),respectively.Moreover,the absence of ligand hindrance can facilitate the interfacial electronic coupling between LF-CPB CL and tetra(4-carboxyphenyl)porphyrin iron(Ⅲ)chloride(Fe-TCPP)cocatalyst,bringing forth significantly accelerated interfacial charge separation.The LF-CPB CL/Fe-TCPP exhibits a total electron consumption rate of 145.6μmol g^(-1) h^(-1) for CO_(2)photoreduction coupled with water oxidation which is over 14 times higher than that of L-CPB NC/FeTCPP.展开更多
Water oxidation is the bottleneck of artificial photosynthesis.Since the first ruthenium-based molecular water oxidation catalyst,the blue dimer,was reported by Meyer’ s group in 1982,catalysts based on transition me...Water oxidation is the bottleneck of artificial photosynthesis.Since the first ruthenium-based molecular water oxidation catalyst,the blue dimer,was reported by Meyer’ s group in 1982,catalysts based on transition metals have been widely employed to explore the mechanism of water oxidation.Because the oxidation of water requires harsh oxidative conditions,the stability of transition complexes under the relevant catalytic conditions has always been a challenge.In this work,we report the redox properties of a CuⅢ complex(TAML-CuⅢ] with a redox-active macrocyclic ligand(TAML) and its reactivity toward catalytic water oxidation.TAML-CuⅢ displayed a completely different electrochemical behavior from that of the TAML-CoⅢ complex previously reported by our group.TAML-CuⅢ can only be oxidized by one-electron oxidation of the ligand to form TAML·+-CuⅢand cannot achieve water activation through the ligand-centered proton-coupled electron transfer that takes place in the case of TAML-CoⅢ.The generated TAML·+-CuⅢ intermediate can undergo further oxidation and ligand hydrolysis with the assistance of borate anions,triggering the formation of a heterogeneous B/CuOx nanocatalyst Therefore,the choice of the buffer solution has a significant influence on the electrochemical behavior and stability of molecular water oxidation catalysts.展开更多
目的人工关节无菌性松动与破骨细胞激活后假体周围骨溶解有关,而NF-κB受体激活因子配体(receptor activator of NF-κB ligand,RANKL)/NF-κB受体激活因子(receptor activator of NF-κB,RANK)信号通路是激活破骨细胞的主要途径,通过...目的人工关节无菌性松动与破骨细胞激活后假体周围骨溶解有关,而NF-κB受体激活因子配体(receptor activator of NF-κB ligand,RANKL)/NF-κB受体激活因子(receptor activator of NF-κB,RANK)信号通路是激活破骨细胞的主要途径,通过建立小鼠气囊植骨模型模拟人工关节无菌性松动环境,观察RANKL抗体抑制炎性反应、减轻溶骨反应的作用。方法取8～10周龄雌性BALB/c小鼠60只(体重18～20 g),取其中20只小鼠颅骨制备骨片,作为气囊植骨供体;剩余40只小鼠随机分为阴性对照组(A组)、阳性对照组(B组)、RANKL抗体低剂量组(C组)和RANKL抗体高剂量组(D组),每组10只。于各组小鼠背部制备2 cm×2 cm大小的气囊后植入1片骨片;于植骨后1 d,A组气囊内注射0.5 mL PBS液;B、C、D组注射0.5 mL钛颗粒悬液。钛颗粒悬液注射前2 d,C、D组气囊内分别注射0.1 mL浓度为50μg/mL和500μg/mL的RANKL抗体,每天1次,连续2 d;A、B组注射0.1 mL PBS液。于植骨后14 d处死全部小鼠,取出植入颅骨骨片和周围囊壁组织,进行大体及组织学观察,并行颅骨骨溶解、骨胶原含量及破骨细胞含量分析。结果各组小鼠均存活至实验完成,切口愈合良好。大体观察见A、C、D组小鼠囊壁炎性反应较轻,偶见渗出和新生血管增生;B组炎性反应严重,见渗出以及新生血管增生。组织学观察见A、C、D组小鼠囊壁炎性细胞浸润及增厚不明显,骨胶原丢失量和破骨细胞含量少;B组大量炎性细胞浸润,囊壁增厚,骨胶原丢失量和破骨细胞含量多。B组炎性细胞数、囊壁厚度、骨胶原丢失量以及破骨细胞含量与A、C、D组比较,差异均有统计学意义(P<0.05)。结论 RANKL抗体可阻断小鼠气囊植骨模型的炎症信号传导通路,有效抑制磨损颗粒所致骨溶解。展开更多
在一种仿G蛋白耦合型信号转导的人工超分子系统中引入类似光化学开关的偶氮苯化合物,用来模拟跨膜受体。合成了三种人工受体的中间体4,4′-二氨基酸酯偶氮苯:Azo-PheOMe(6a)、Azo-ValOMe(6b)、Azo-GluOMe(6c)、Azo-SerOMe(6d)、Azo-ThrO...在一种仿G蛋白耦合型信号转导的人工超分子系统中引入类似光化学开关的偶氮苯化合物,用来模拟跨膜受体。合成了三种人工受体的中间体4,4′-二氨基酸酯偶氮苯:Azo-PheOMe(6a)、Azo-ValOMe(6b)、Azo-GluOMe(6c)、Azo-SerOMe(6d)、Azo-ThrOMe(6e)及Azo-PheOEt(6a′)、Azo-ValOEt(6b′)、Azo-GluOEt(6c′)、Azo-SerOEt(6d′)、Azo-ThrOEt(6e′)并采用1 H NMR谱、紫外可见光谱、元素分析以及红外光谱进行了表征。以6a为主要研究对象,分别在两种不同介质(三氯甲烷和甲醇)中,在365nm的紫外光下进行照射不同时间后,发现6a从反式变为顺式,再置于427nm的可见光下,又从顺式变回反式,所需时间不同,并且其最大吸收波长发生了红移,为模拟信号转导体系中受体之构象的变化作初步研究。展开更多
基金financially supported by the Natural Science Foundation of Tianjin City(17JCJQJC43800)the National Key R&D Program of China(2017YFA0700104)+1 种基金the National Science Foundation of China(21931007,U21A20286)Jiangsu Funding Program for Excellent Postdoctoral Talent and the 111 Project of China(D17003)。
文摘The low-efficiency CO_(2) uptake capacity and insufficient photogenerated exciton dissociation of current metal halide perovskite(MHP)nanocrystals with end-capping ligands extremely restrict their application in the field of artificial photosynthesis.Herein,we demonstrate that ligand-free CsPbBr_(3) with calliandralike nanostructure(LF-CPB CL)can be synthesized easily through a ligand-free seed-assisted dissolutionrecrystallization growth process,exhibiting significantly enhanced CO_(2) uptake capacity.More specifically,the abundant surface bromine(Br)vacancies in ligand-free MHP materials are demonstrated to be beneficial to photogenerated carrier separation.The electron consumption rate of LF-CPB CL for photocatalytic CO_(2) reduction increases 7 and 20 times over those of traditional ligand-capping CsPbBr_(3)nanocrystal(L-CPB NC)and bulk CsPbBr_(3),respectively.Moreover,the absence of ligand hindrance can facilitate the interfacial electronic coupling between LF-CPB CL and tetra(4-carboxyphenyl)porphyrin iron(Ⅲ)chloride(Fe-TCPP)cocatalyst,bringing forth significantly accelerated interfacial charge separation.The LF-CPB CL/Fe-TCPP exhibits a total electron consumption rate of 145.6μmol g^(-1) h^(-1) for CO_(2)photoreduction coupled with water oxidation which is over 14 times higher than that of L-CPB NC/FeTCPP.
文摘Water oxidation is the bottleneck of artificial photosynthesis.Since the first ruthenium-based molecular water oxidation catalyst,the blue dimer,was reported by Meyer’ s group in 1982,catalysts based on transition metals have been widely employed to explore the mechanism of water oxidation.Because the oxidation of water requires harsh oxidative conditions,the stability of transition complexes under the relevant catalytic conditions has always been a challenge.In this work,we report the redox properties of a CuⅢ complex(TAML-CuⅢ] with a redox-active macrocyclic ligand(TAML) and its reactivity toward catalytic water oxidation.TAML-CuⅢ displayed a completely different electrochemical behavior from that of the TAML-CoⅢ complex previously reported by our group.TAML-CuⅢ can only be oxidized by one-electron oxidation of the ligand to form TAML·+-CuⅢand cannot achieve water activation through the ligand-centered proton-coupled electron transfer that takes place in the case of TAML-CoⅢ.The generated TAML·+-CuⅢ intermediate can undergo further oxidation and ligand hydrolysis with the assistance of borate anions,triggering the formation of a heterogeneous B/CuOx nanocatalyst Therefore,the choice of the buffer solution has a significant influence on the electrochemical behavior and stability of molecular water oxidation catalysts.
文摘在一种仿G蛋白耦合型信号转导的人工超分子系统中引入类似光化学开关的偶氮苯化合物,用来模拟跨膜受体。合成了三种人工受体的中间体4,4′-二氨基酸酯偶氮苯:Azo-PheOMe(6a)、Azo-ValOMe(6b)、Azo-GluOMe(6c)、Azo-SerOMe(6d)、Azo-ThrOMe(6e)及Azo-PheOEt(6a′)、Azo-ValOEt(6b′)、Azo-GluOEt(6c′)、Azo-SerOEt(6d′)、Azo-ThrOEt(6e′)并采用1 H NMR谱、紫外可见光谱、元素分析以及红外光谱进行了表征。以6a为主要研究对象,分别在两种不同介质(三氯甲烷和甲醇)中,在365nm的紫外光下进行照射不同时间后,发现6a从反式变为顺式,再置于427nm的可见光下,又从顺式变回反式,所需时间不同,并且其最大吸收波长发生了红移,为模拟信号转导体系中受体之构象的变化作初步研究。
