The formation of two parent divergent ligands derived from 1,4-bis(pyrid-3-yl)benzene is reported.The synthetic route involves condensation of alloxan with a dibromodiamine precursor,followed by benzylation,leading,af...The formation of two parent divergent ligands derived from 1,4-bis(pyrid-3-yl)benzene is reported.The synthetic route involves condensation of alloxan with a dibromodiamine precursor,followed by benzylation,leading,after the Suzuki-Miyaura cross-coupling reaction,to the formation of two ligands:L1,bearing the well-known pteridine-dione moiety,and L2,in which ring contraction and symmetrisation occur,resulting in an imidazopyrazinone core.The synthesis of L1 and L2,along with their characterization in solution and in the solid state,is reported.Electrochemical studies of L1 and L2 solutions revealed analogous two-electron reduction processes,with the first reduction step leading to radical species,as confirmed by EPR spectroelectrochemistry.For L1,the first and second reductions occur at E_(Red1)=−0,80 V and E_(Red2)=−1.35 V vs.Ag/AgCl,in agreement with the values reported for other pteridine-dione species,whereas L2 displays more negative reduction potentials,shifted by approximately 0.7 V.These observations were confirmed by DFT calculations.The coordination abilities of L1 and L2 were investigated.Single-crystal X-ray diffraction(SCXRD)revealed the formation of a pillared 3D compound,L2-Zn,obtained by mixing L2,4,4’-biphenyldicarboxylic acid(H_(2)bpdc)and a Zn^(2+)salt under solvothermal conditions.A series of powdered isostructural L2-M compounds(M=Zn,Ni,Co)was synthesized and characterized by powder X-ray diffraction(PXRD).Under the same conditions,using L1 instead of L2 led to the formation of poorly diffracting crystals,which nevertheless exhibited a three-dimensional pillared architecture.A complete series of powdered isostructural L1-M compounds(M=Co,Ni,Cu and Zn)was evidenced.The solid-state electrochemical behavior of the L2-M analogues(M=Zn and Co)was preliminarily investigated,revealing ligand-based reduction processes occurring within the three-dimensional pillared structure for both L2-Zn and L2-Co.展开更多
A series of polymetallic Cu_((I))assemblies C_(1-4)was selectively obtained by self-assembly of a preorganized trimetallic precursor B with 3,3’-bipyridine ligand L_(1)and structurally related longer ligands C_(2-4),...A series of polymetallic Cu_((I))assemblies C_(1-4)was selectively obtained by self-assembly of a preorganized trimetallic precursor B with 3,3’-bipyridine ligand L_(1)and structurally related longer ligands C_(2-4),respectively,allowing to investigate the impact of ligands’backbones on architectures on the derivatives C_(1-4).While linkers L_(1)and L_(2)led to the formation of 1D coordination polymers(C_(1,2)),the newly prepared alloxazine-functionalized ligands L_(3)and L_(4),promoting the appearance of steric constraints andπ-πinteractions,led to the formation of discrete hexametallacycles(C_(3,4)).Structural characterization via X-ray diffraction confirmed the role of ligand design in determining the final architectures.The solid-state photophysical properties of ligands L_(3)and L_(4),trimetallic precursor B and derivatives C_(1-4).are reported.L_(3)and L_(4)exhibit weak yellow fluorescence at room temperature(RT),while the trimetallic precursor B displays intense yellow ^(3)MLCT phosphorescence at RT.Assemblies C_(1-4)show varied photophysical behaviors including ^(3)MLCT phosphorescence for C_(1),ligand centered phosphorescence and fluorescence for C2and C4,respectively,while C3is non-emissive.This study provides new insights into the steric and electronic factors governing Cu_((I))-based luminescent materials’preparation,highlighting diverse photophysical behaviors including efficient RT emission performances.展开更多
基金Financial support from the University of Strasbourg,Unistra,and the CNRS(INC)is acknowledgedWe thank the Agence Nationale de la Recherche(ANR)through the BattAllox Project ANR-20-CE05-0005The French research infrastructure INFRANALYTICS FR2054 is acknowledged for its support.
文摘The formation of two parent divergent ligands derived from 1,4-bis(pyrid-3-yl)benzene is reported.The synthetic route involves condensation of alloxan with a dibromodiamine precursor,followed by benzylation,leading,after the Suzuki-Miyaura cross-coupling reaction,to the formation of two ligands:L1,bearing the well-known pteridine-dione moiety,and L2,in which ring contraction and symmetrisation occur,resulting in an imidazopyrazinone core.The synthesis of L1 and L2,along with their characterization in solution and in the solid state,is reported.Electrochemical studies of L1 and L2 solutions revealed analogous two-electron reduction processes,with the first reduction step leading to radical species,as confirmed by EPR spectroelectrochemistry.For L1,the first and second reductions occur at E_(Red1)=−0,80 V and E_(Red2)=−1.35 V vs.Ag/AgCl,in agreement with the values reported for other pteridine-dione species,whereas L2 displays more negative reduction potentials,shifted by approximately 0.7 V.These observations were confirmed by DFT calculations.The coordination abilities of L1 and L2 were investigated.Single-crystal X-ray diffraction(SCXRD)revealed the formation of a pillared 3D compound,L2-Zn,obtained by mixing L2,4,4’-biphenyldicarboxylic acid(H_(2)bpdc)and a Zn^(2+)salt under solvothermal conditions.A series of powdered isostructural L2-M compounds(M=Zn,Ni,Co)was synthesized and characterized by powder X-ray diffraction(PXRD).Under the same conditions,using L1 instead of L2 led to the formation of poorly diffracting crystals,which nevertheless exhibited a three-dimensional pillared architecture.A complete series of powdered isostructural L1-M compounds(M=Co,Ni,Cu and Zn)was evidenced.The solid-state electrochemical behavior of the L2-M analogues(M=Zn and Co)was preliminarily investigated,revealing ligand-based reduction processes occurring within the three-dimensional pillared structure for both L2-Zn and L2-Co.
基金supported by the CNRS,the ANR(ANR PRC SMAC and ANR PRCI SUPRALUM),the French‘Ministère de l’Enseignement Supérieur,de la Recherche et de l’Innovation’and the French‘Ministère des Affaires Etrangères’the Alexander von Humboldt Foundation for a fellowship for experienced researchersupport from the University of Strasbourg Agence Nationale de la Recherche(ANR)through BattAllox project ANR-20-CE05-0005 are acknowledged.
文摘A series of polymetallic Cu_((I))assemblies C_(1-4)was selectively obtained by self-assembly of a preorganized trimetallic precursor B with 3,3’-bipyridine ligand L_(1)and structurally related longer ligands C_(2-4),respectively,allowing to investigate the impact of ligands’backbones on architectures on the derivatives C_(1-4).While linkers L_(1)and L_(2)led to the formation of 1D coordination polymers(C_(1,2)),the newly prepared alloxazine-functionalized ligands L_(3)and L_(4),promoting the appearance of steric constraints andπ-πinteractions,led to the formation of discrete hexametallacycles(C_(3,4)).Structural characterization via X-ray diffraction confirmed the role of ligand design in determining the final architectures.The solid-state photophysical properties of ligands L_(3)and L_(4),trimetallic precursor B and derivatives C_(1-4).are reported.L_(3)and L_(4)exhibit weak yellow fluorescence at room temperature(RT),while the trimetallic precursor B displays intense yellow ^(3)MLCT phosphorescence at RT.Assemblies C_(1-4)show varied photophysical behaviors including ^(3)MLCT phosphorescence for C_(1),ligand centered phosphorescence and fluorescence for C2and C4,respectively,while C3is non-emissive.This study provides new insights into the steric and electronic factors governing Cu_((I))-based luminescent materials’preparation,highlighting diverse photophysical behaviors including efficient RT emission performances.
