Efforts to develop organometallic complexes for catalytic nitrogen reduction have seen significant progress in recent years.However,the strategies for improving the activity of the homogenous catalysts have mainly foc...Efforts to develop organometallic complexes for catalytic nitrogen reduction have seen significant progress in recent years.However,the strategies for improving the activity of the homogenous catalysts have mainly focused on alternating ligands and metals.Herein,we report that the activity and stability of a PN_(P-Mo pincer complex(2)toward dinitrogen(N_(2))reduction were greatly enhanced through postmodification of the PN^(3)P pincer framework of its parent complex(1).A high ratio of NH_(3)/Mo(3525)was achieved in the presence of SmI_(2)as a reductant.In sharp contrast,1 only afforded an NH_(3)/Mo ratio of 21.Moreover,when supported by an anionic pincer ligand,2 furnished a high oxidation state Mo(V)-nitride complex via N_(2)cleavage as a plausible key intermediate in the catalytic process,suggesting a catalytic cycle that may involve different oxidation states(Ⅱ/Ⅴ)from those with 10-πelectron configuration in the literature.展开更多
A postsynthetic modification method was used to prepare salicylaldehyde functionalized metal-organicframeworks through the nucleophilic addition of salicylaldehyde with the amine group present in the frameworks ofNH2-...A postsynthetic modification method was used to prepare salicylaldehyde functionalized metal-organicframeworks through the nucleophilic addition of salicylaldehyde with the amine group present in the frameworks ofNH2-MIL-53（A1）. Hydroxyl groups were successfully grafted onto NI-I2-MIL-53（A1）, and imine groups were formed.Importantly, these hydroxyl and imine groups of the resulting NH2-MIL-53（A1）-SA can be used as the anchoringgroup to stabilise Au^3＋ ions and Au^0 nanoparticles（NPs）. By doing this, Au^3＋ ions and Au^0 NPs were successfully en-capsulated in the cages of NH2-MIL-53（A1） by a simple impregnation method. The resulting gold functionalizedNH2-MIL-53（AI） showed good catalytic activities in the one-pot synthesis of structurally divergent propargylaminesby three-component coupling reactions of aldehydes, amines and alkynes. Various aromatic/aliphatic aldehydes, aro-matic alkynes, and piperidine were able to undergo three-component coupling on NH2-MIL-53（A1）-Au. In addition,the catalyst NH2-M/L-53（A/）-Au was recovered easily by centrifugation and reused up to four times. Thus, it can beused for the environmentally friendly synthesis ofpropargylamines.展开更多
文摘Efforts to develop organometallic complexes for catalytic nitrogen reduction have seen significant progress in recent years.However,the strategies for improving the activity of the homogenous catalysts have mainly focused on alternating ligands and metals.Herein,we report that the activity and stability of a PN_(P-Mo pincer complex(2)toward dinitrogen(N_(2))reduction were greatly enhanced through postmodification of the PN^(3)P pincer framework of its parent complex(1).A high ratio of NH_(3)/Mo(3525)was achieved in the presence of SmI_(2)as a reductant.In sharp contrast,1 only afforded an NH_(3)/Mo ratio of 21.Moreover,when supported by an anionic pincer ligand,2 furnished a high oxidation state Mo(V)-nitride complex via N_(2)cleavage as a plausible key intermediate in the catalytic process,suggesting a catalytic cycle that may involve different oxidation states(Ⅱ/Ⅴ)from those with 10-πelectron configuration in the literature.
文摘A postsynthetic modification method was used to prepare salicylaldehyde functionalized metal-organicframeworks through the nucleophilic addition of salicylaldehyde with the amine group present in the frameworks ofNH2-MIL-53（A1）. Hydroxyl groups were successfully grafted onto NI-I2-MIL-53（A1）, and imine groups were formed.Importantly, these hydroxyl and imine groups of the resulting NH2-MIL-53（A1）-SA can be used as the anchoringgroup to stabilise Au^3＋ ions and Au^0 nanoparticles（NPs）. By doing this, Au^3＋ ions and Au^0 NPs were successfully en-capsulated in the cages of NH2-MIL-53（A1） by a simple impregnation method. The resulting gold functionalizedNH2-MIL-53（AI） showed good catalytic activities in the one-pot synthesis of structurally divergent propargylaminesby three-component coupling reactions of aldehydes, amines and alkynes. Various aromatic/aliphatic aldehydes, aro-matic alkynes, and piperidine were able to undergo three-component coupling on NH2-MIL-53（A1）-Au. In addition,the catalyst NH2-M/L-53（A/）-Au was recovered easily by centrifugation and reused up to four times. Thus, it can beused for the environmentally friendly synthesis ofpropargylamines.
