While nickel(II)complexes have been widely used as catalysts for carbon-carbon coupling reactions,the exploration of their photophysical and photochemical properties is still in the infancy.Here,a series of square-pla...While nickel(II)complexes have been widely used as catalysts for carbon-carbon coupling reactions,the exploration of their photophysical and photochemical properties is still in the infancy.Here,a series of square-planar Ni(II)complexes[(diNHC)NiX2]bearing chelating benzimidazole-based bis(N-heterocyclic carbene)ligands and varying anionic coligands(1,X=Cl;2,X=Br;3,X=I)are synthesized and structurally characterized.In solid state,both 1 and 2 exhibit orange-red photoluminescence under ambient conditions.The photophysical and electrochemical measurements along with density functional theory(DFT)calculations reveal that the low-energy emissions can be attributed to singlet excited states with ligand-to-ligand charge-transfer(LLCT)character.This work suggests that strong-field N-heterocyclic carbene ligands play a crucial role to achieve the luminescence of Ni(II)complexes.展开更多
Organic room temperature phosphorescence(RTP)in water has attracted much attention recently for its potential biological applications.However,it remains a formidable challenge to achieve efficient RTP from pure organi...Organic room temperature phosphorescence(RTP)in water has attracted much attention recently for its potential biological applications.However,it remains a formidable challenge to achieve efficient RTP from pure organic compounds in aqueous phase due to the dramatic deactivation of triplet excited states in water and the poor water dispersibility of large organic particles/crystals.Represented herein is covalent incorporation of a pure organic monochromophore in silica nanoparticles(SiNPs)featuring fluorescence and bright phosphorescence in aqueous solution.The covalent bonding of organic phosphors in polysiloxane framework was found to show excellent water dispersibility,at the same time suppress the nonradiative deactivation of triplet excited states especially from water,thus leading to high phosphorescence quantum yields(up to 22%)and long lifetimes(up to 3.5 ms)in aqueous phase.More strikingly,oxygen-insensitive fluorescence as internal reference and oxygen-dependent phosphorescence as oxygen indicator from the organic chromophore in the porous SiNPs realized ratiometric hypoxia detection with ultrasensitivity(K_(SV)=449.3 bar^(-1)).展开更多
基金the Natural Science Foundation of China(No.22175191)Y.C.thanks the financial support from CAS-Croucher Funding Scheme for Joint Laboratories and Beijing Municipal Science&Technology Commission(No.Z211100007921020).
文摘While nickel(II)complexes have been widely used as catalysts for carbon-carbon coupling reactions,the exploration of their photophysical and photochemical properties is still in the infancy.Here,a series of square-planar Ni(II)complexes[(diNHC)NiX2]bearing chelating benzimidazole-based bis(N-heterocyclic carbene)ligands and varying anionic coligands(1,X=Cl;2,X=Br;3,X=I)are synthesized and structurally characterized.In solid state,both 1 and 2 exhibit orange-red photoluminescence under ambient conditions.The photophysical and electrochemical measurements along with density functional theory(DFT)calculations reveal that the low-energy emissions can be attributed to singlet excited states with ligand-to-ligand charge-transfer(LLCT)character.This work suggests that strong-field N-heterocyclic carbene ligands play a crucial role to achieve the luminescence of Ni(II)complexes.
基金Beijing Natural Science Foundation,Grant/Award Number:2222033National Natural Science Foundation of China,Grant/Award Numbers:22071258,21871280,22193013,22088102+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences,Grant/Award Number:XDB17000000Natural Science Foundation of Shanxi Province of China,Grant/Award Number:201901D111138。
文摘Organic room temperature phosphorescence(RTP)in water has attracted much attention recently for its potential biological applications.However,it remains a formidable challenge to achieve efficient RTP from pure organic compounds in aqueous phase due to the dramatic deactivation of triplet excited states in water and the poor water dispersibility of large organic particles/crystals.Represented herein is covalent incorporation of a pure organic monochromophore in silica nanoparticles(SiNPs)featuring fluorescence and bright phosphorescence in aqueous solution.The covalent bonding of organic phosphors in polysiloxane framework was found to show excellent water dispersibility,at the same time suppress the nonradiative deactivation of triplet excited states especially from water,thus leading to high phosphorescence quantum yields(up to 22%)and long lifetimes(up to 3.5 ms)in aqueous phase.More strikingly,oxygen-insensitive fluorescence as internal reference and oxygen-dependent phosphorescence as oxygen indicator from the organic chromophore in the porous SiNPs realized ratiometric hypoxia detection with ultrasensitivity(K_(SV)=449.3 bar^(-1)).
基金the financial support from the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB17000000)the National Natural Science Foundation of China (21773275 and 21971250)the financial support from K.C. Wong Education Foundation and the CAS-Croucher Funding Scheme for Joint Laboratories。