Mesoionic imines(MIIs)based on a 1,2,3-triazole core have been popularized in the past ca.5 years.In this review article we discuss the synthesis,coordination ability and the structural and spectroscopic properties of...Mesoionic imines(MIIs)based on a 1,2,3-triazole core have been popularized in the past ca.5 years.In this review article we discuss the synthesis,coordination ability and the structural and spectroscopic properties of this fascinating class of electronically ambivalent compounds.Apart from this,we also discuss the utility of MIIs and their compounds in directed C-H activation reactions,and in the activation and conversion of small molecules such as alkynes and CO_(2).Based on the current state of the art,we touch upon possible future developments of the chemistry of these classes of molecules.展开更多
Triazolylidenes are an emerging class of mesoionic carbenes with potential as ligands in homogeneous catalysis.In this contribution we present well-defined dicopper(Ⅰ)complexes with di-mesoionic carbenes where the co...Triazolylidenes are an emerging class of mesoionic carbenes with potential as ligands in homogeneous catalysis.In this contribution we present well-defined dicopper(Ⅰ)complexes with di-mesoionic carbenes where the copper centers are held at a distance of about 2.8Å.All complexes display excellent activity as pre-catalysts for the azide–alkyne cycloaddition(click)reaction.Comparisons with analogous mononuclear complexes show the dinuclear pre-catalysts to be twice as active for the same amount of copper used.These results thus point to potentially strong cooperative effects in these dinuclear complexes,and further support the recently established dinuclear reaction pathway for the click reaction.The results presented here provide a synthetic route for generating dinuclear complexes with di-mesoionic carbenes with relatively short metal–metal distances,and opens a general platform for investigating potential cooperative effects in catalysis.展开更多
The controllable construction of light-emitting organometallic supramolecular materials integrating stimulus responses and biological applications is still a major challenge today.In this work,emissive organometallic ...The controllable construction of light-emitting organometallic supramolecular materials integrating stimulus responses and biological applications is still a major challenge today.In this work,emissive organometallic assemblies based on AgI/AuI and mesoionic carbene-decorated tetraphenylethene(MIC-TPE)ligands have been synthesized and characterized.Photophysical studies showed that these organometallic assemblies[M_(4)(2)_(2)](OTf)_(4) not only fluoresce in various dilute solutions,resulting from the rigidification of MIC-TPE ligands upon complexation,but also show tunable fluorescence wavelengths and intensity behaviors in mixed solvent systems and at varying temperatures while in solution,and mechanical pressure stimulus-responsive fluorescent features in the solid state.Furthermore,the organometallic cages[M_(4)(2)_(2)](OTf)_(4)(M=Ag and Au)were successfully employed for cell imaging and showed the potential of anticancer activity,making them promising candidates for cancer theranostics.This work provides a simple and efficient method to prepare highly emissive and stimulus-responsive organometallic materials and paves the way for related biological applications such as cancer cell imaging and targeted therapy.展开更多
Ionic liquids are green solvents with interesting properties:displaying low melting points and high boiling points.They offer a new approach applicable in many instances.Nevertheless,the presence of free ions can be a...Ionic liquids are green solvents with interesting properties:displaying low melting points and high boiling points.They offer a new approach applicable in many instances.Nevertheless,the presence of free ions can be a matter in some cases,e.g.for the study of nucleophilic reactions,in electrochemistry,and in each situation where there is a competition between counter ions,as in micellization of ionic surfactants.Neutral compounds having formal unit electrical charges of opposite sign,and the same physical properties than ionic liquids would be a nice alternative to these latter solvents.There are two classes of chemical compounds having these characteristics:zwitterionic liquids(with no uncharged canonical representation) and mesoionic liquids(in which the negative and the positive charges are delocalized).In that last class we have chosen to work with 3-methylsydnone in order to examine,in this aprotic solvent,if it was possible to observe aggregation of surfactants in the same manner as in water.With all kinds of surfactants studied(ionic,zwitterionic and mesoionic) we have been able to demonstrate the formation of direct micelles:hydrogen bonding is thus not mandatory for molecular aggregation.Comparison of the behavior in water and in formamide showed that solvophobic interactions were qualitatively comparable but with a lower intensity.展开更多
We describe an iridium-catalyzed ortho-selective C–H borylation of unprotected anilines.The employing strongσ-donating cyclometalated mesoionic carbene as C^C bidentate ligand is crucial for the high ortho-selectivi...We describe an iridium-catalyzed ortho-selective C–H borylation of unprotected anilines.The employing strongσ-donating cyclometalated mesoionic carbene as C^C bidentate ligand is crucial for the high ortho-selectivity.Computational studies support outer-sphere X–H⋅⋅⋅O_(boryl) hydrogen bond interactions,which are strengthened by bidentate C^C ligand introduction.The method shows broad substrate scope and high functional group tolerance.展开更多
基金Deutsche Forschungsgemeinschaft(DFG)for funding primary research in our group which has partly contributed to the results summarized in this perspective。
文摘Mesoionic imines(MIIs)based on a 1,2,3-triazole core have been popularized in the past ca.5 years.In this review article we discuss the synthesis,coordination ability and the structural and spectroscopic properties of this fascinating class of electronically ambivalent compounds.Apart from this,we also discuss the utility of MIIs and their compounds in directed C-H activation reactions,and in the activation and conversion of small molecules such as alkynes and CO_(2).Based on the current state of the art,we touch upon possible future developments of the chemistry of these classes of molecules.
文摘Triazolylidenes are an emerging class of mesoionic carbenes with potential as ligands in homogeneous catalysis.In this contribution we present well-defined dicopper(Ⅰ)complexes with di-mesoionic carbenes where the copper centers are held at a distance of about 2.8Å.All complexes display excellent activity as pre-catalysts for the azide–alkyne cycloaddition(click)reaction.Comparisons with analogous mononuclear complexes show the dinuclear pre-catalysts to be twice as active for the same amount of copper used.These results thus point to potentially strong cooperative effects in these dinuclear complexes,and further support the recently established dinuclear reaction pathway for the click reaction.The results presented here provide a synthetic route for generating dinuclear complexes with di-mesoionic carbenes with relatively short metal–metal distances,and opens a general platform for investigating potential cooperative effects in catalysis.
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation(NSFC)(grant nos.22025107,21722105,and 21771146)the National Youth Top-notch Talent Support Program of China,the Key Science and Technology Innovation Team of Shaanxi Province(nos.2019TD-007 and 2019JLZ-02)the FM&EM International Joint Laboratory of Northwest University.
文摘The controllable construction of light-emitting organometallic supramolecular materials integrating stimulus responses and biological applications is still a major challenge today.In this work,emissive organometallic assemblies based on AgI/AuI and mesoionic carbene-decorated tetraphenylethene(MIC-TPE)ligands have been synthesized and characterized.Photophysical studies showed that these organometallic assemblies[M_(4)(2)_(2)](OTf)_(4) not only fluoresce in various dilute solutions,resulting from the rigidification of MIC-TPE ligands upon complexation,but also show tunable fluorescence wavelengths and intensity behaviors in mixed solvent systems and at varying temperatures while in solution,and mechanical pressure stimulus-responsive fluorescent features in the solid state.Furthermore,the organometallic cages[M_(4)(2)_(2)](OTf)_(4)(M=Ag and Au)were successfully employed for cell imaging and showed the potential of anticancer activity,making them promising candidates for cancer theranostics.This work provides a simple and efficient method to prepare highly emissive and stimulus-responsive organometallic materials and paves the way for related biological applications such as cancer cell imaging and targeted therapy.
文摘Ionic liquids are green solvents with interesting properties:displaying low melting points and high boiling points.They offer a new approach applicable in many instances.Nevertheless,the presence of free ions can be a matter in some cases,e.g.for the study of nucleophilic reactions,in electrochemistry,and in each situation where there is a competition between counter ions,as in micellization of ionic surfactants.Neutral compounds having formal unit electrical charges of opposite sign,and the same physical properties than ionic liquids would be a nice alternative to these latter solvents.There are two classes of chemical compounds having these characteristics:zwitterionic liquids(with no uncharged canonical representation) and mesoionic liquids(in which the negative and the positive charges are delocalized).In that last class we have chosen to work with 3-methylsydnone in order to examine,in this aprotic solvent,if it was possible to observe aggregation of surfactants in the same manner as in water.With all kinds of surfactants studied(ionic,zwitterionic and mesoionic) we have been able to demonstrate the formation of direct micelles:hydrogen bonding is thus not mandatory for molecular aggregation.Comparison of the behavior in water and in formamide showed that solvophobic interactions were qualitatively comparable but with a lower intensity.
基金This work was supported by the National Natural Science Foundation of China(Nos.22171284 and 21602249)the Fundamental Research Funds for the Central Universities,the Research Funds of Renmin University of China(No.20XNLG20)the Public Computing Cloud Platform,Renmin University of China.
文摘We describe an iridium-catalyzed ortho-selective C–H borylation of unprotected anilines.The employing strongσ-donating cyclometalated mesoionic carbene as C^C bidentate ligand is crucial for the high ortho-selectivity.Computational studies support outer-sphere X–H⋅⋅⋅O_(boryl) hydrogen bond interactions,which are strengthened by bidentate C^C ligand introduction.The method shows broad substrate scope and high functional group tolerance.
