Metal complexes containing organic photoswitches are capable of modulating the steric and electronic environment around the metal center through photoisomerization,enabling their use in photoswitchable catalysis.Herei...Metal complexes containing organic photoswitches are capable of modulating the steric and electronic environment around the metal center through photoisomerization,enabling their use in photoswitchable catalysis.Herein,we design a new class of photoswitchable tripodal tetradentate ligands L1-L3 that can readily form air-stable Cu(Ⅰ)complexes(C1-PF_(6),C1-BF_(4),C2,C3).The design strategy integrates flexible spacers and phenylazopyrazole units in the same ligand framework that ensures efficient photoisomerization and sustained stability of the photoswitched state.The complexes were screened for catalyzing the CuAAC reaction between alkynes and azides and C1-PF_(6)was identified as a catalyst capable of exerting temporal control over the reaction through photoisomerization.Based on the optimized conditions and the substrate scope,the ZZZ(photoswitched)form of complex C1-PF_(6)exhibits substantially improved catalytic performance compared to its EEE(native)form.In this article,we describe detailed experimental and computational investigations aimed at understanding how photoisomerization regulates the catalytic activity of Cu(Ⅰ)complexes of arylazopyrazole-based tripodal tetradentate ligands.展开更多
Ni(0)nanoparticles(NPs)are unstable and tend to aggregate in water,which poses a considerable challenge in their catalytic application.To overcome these drawbacks,integrated Ni-noble metal bimetallic NPs with a hollow...Ni(0)nanoparticles(NPs)are unstable and tend to aggregate in water,which poses a considerable challenge in their catalytic application.To overcome these drawbacks,integrated Ni-noble metal bimetallic NPs with a hollow-structured support are expected to enhance performances in heterogeneous catalysis.Herein,we present a simple approach for facile fabrication of Ni NPs embedded in a carbon layer on raspberry-like SiO_(2) hollow nanocages with a hydrophobic surface(SiO_(2)@C-Ni).Owing to the high affinity between Ni and histine-rich protein,the resultant raspberry-like SiO_(2)@C-Ni composites exhibit good performance in the adsorption of His-rich protein.Moreover,by the galvanic replacement reaction between Ni and Pd2+,hollow structured SiO_(2)@C-PdNi composites are easily obtained,while endowing the SiO_(2)@C-PdNi composites with a hydrophilic surface,greatly beneficial for the catalysis reaction in the aqueous phase.More attractively,the synthetic strategy could be extended to the synthesis of other Nibased bimetallic alloy NPs,such as SiO_(2)@C-AgNi and SiO_(2)@C-AuNi composites.This work highlights the superiority of transition metal ion mediated RF chemistry,the sol–gel process and emulsifier-free polymerization in the ingenious design of hollow structured materials embedded with well-dispersed metal alloy NPs.展开更多
基金DST Indo-Czech Republic Bilateral Scientific Research Cooperation,Ministry of Science and Technology,New Delhi,India(DST/INT/CZ/P-17/2019)the Science and Engineering Research Board(SERB),New Delhi for the financial support(CRG/2023/003861)+1 种基金SERB for funding(SB/SJF/2019-20/12,CRG/2022/001697)IISER Mohali for financial support,the departmental and central research facilities and other instruments(XRD,NMR,and HRMS including DST-FIST 400 MHz NMR facility,SR/FIST/CS-II/2019/94(C)TPN No.32545).
文摘Metal complexes containing organic photoswitches are capable of modulating the steric and electronic environment around the metal center through photoisomerization,enabling their use in photoswitchable catalysis.Herein,we design a new class of photoswitchable tripodal tetradentate ligands L1-L3 that can readily form air-stable Cu(Ⅰ)complexes(C1-PF_(6),C1-BF_(4),C2,C3).The design strategy integrates flexible spacers and phenylazopyrazole units in the same ligand framework that ensures efficient photoisomerization and sustained stability of the photoswitched state.The complexes were screened for catalyzing the CuAAC reaction between alkynes and azides and C1-PF_(6)was identified as a catalyst capable of exerting temporal control over the reaction through photoisomerization.Based on the optimized conditions and the substrate scope,the ZZZ(photoswitched)form of complex C1-PF_(6)exhibits substantially improved catalytic performance compared to its EEE(native)form.In this article,we describe detailed experimental and computational investigations aimed at understanding how photoisomerization regulates the catalytic activity of Cu(Ⅰ)complexes of arylazopyrazole-based tripodal tetradentate ligands.
基金the financial support provided by the Natural Science Foundation of Shanghai City(18ZR1416400)the Fundamental Research Funds for the Central Universities(PA2020GDKC0005)the National Key R&D Program of China(no.2018YFC1801503).
文摘Ni(0)nanoparticles(NPs)are unstable and tend to aggregate in water,which poses a considerable challenge in their catalytic application.To overcome these drawbacks,integrated Ni-noble metal bimetallic NPs with a hollow-structured support are expected to enhance performances in heterogeneous catalysis.Herein,we present a simple approach for facile fabrication of Ni NPs embedded in a carbon layer on raspberry-like SiO_(2) hollow nanocages with a hydrophobic surface(SiO_(2)@C-Ni).Owing to the high affinity between Ni and histine-rich protein,the resultant raspberry-like SiO_(2)@C-Ni composites exhibit good performance in the adsorption of His-rich protein.Moreover,by the galvanic replacement reaction between Ni and Pd2+,hollow structured SiO_(2)@C-PdNi composites are easily obtained,while endowing the SiO_(2)@C-PdNi composites with a hydrophilic surface,greatly beneficial for the catalysis reaction in the aqueous phase.More attractively,the synthetic strategy could be extended to the synthesis of other Nibased bimetallic alloy NPs,such as SiO_(2)@C-AgNi and SiO_(2)@C-AuNi composites.This work highlights the superiority of transition metal ion mediated RF chemistry,the sol–gel process and emulsifier-free polymerization in the ingenious design of hollow structured materials embedded with well-dispersed metal alloy NPs.
