The idea of preparation a water-soluble Pt-containing AIEgen was successfully realized by direct reversible addition-fragmentation transfer copolymerization of a Pt(II)complex(LPtPV)containing a vinyl group and polyvi...The idea of preparation a water-soluble Pt-containing AIEgen was successfully realized by direct reversible addition-fragmentation transfer copolymerization of a Pt(II)complex(LPtPV)containing a vinyl group and polyvinylpyrrolidone(p(VP)).The resulting block-copolymer p(VP-b-LPtPV)containing 5–8 Pt(II)chromophores exhibits intriguing photophysical properties—strong solvent and concentration dependence of absorption and emission characteristics.Various physicochemical and analytical methods(NMR spectroscopy,XRD analysis,ESI-MS,AUC,DLS,ICP-OES,GPC,viscometry,TEM)were used to characterize the initial complex,its binuclear analogs,p(VP)and p(VP-b-LPtPV).The obtained data indicate that the photophysical properties of the latter are dictated by the type of aggregation process rather than solvatochromic effects.It is shown that at low concentration in organic solvents,the platinum chromophores aggregation is either absent(dimethylformamide)or occurs predominantly at intramolecular level(MeCN),whereas in aqueous media,p(VP-b-LPtPV)readily aggregates into micellar-type nanoparticles with a hydrophilic p(VP)corona and a hydrophobic Pt-containing core,in which strong intra-and intermolecular Pt⋅⋅⋅Pt and/orπ⋅⋅⋅πinteractions result in a significant red shift of absorption and emission down to 600 and 816 nm,respectively.Despite of emission shift into NIR area where emission is commonly quenched by nonradiative vibrational relaxation,an increase in the emission quantum yield occurs in complete agreement with the typical aggregation-induced emission(AIE)emitters’behavior.Quantum mechanics/molecular mechanics simulations of aggregation processes also confirm the trends in the relationship between aggregation mode and photophysical behavior,particularly,in the variations of energy gaps between the ground state of the AIEgens and their excited singlet and triplet states.展开更多
Strongly blue fluorescent 1-phenyl-2-(pyridin-2-yl)-1H-phenanthro[9,10-d]imidazole(L1)is a facile block for the construction of multichromophore organic molecules,and simultaneously serves as a chelating diimine ligan...Strongly blue fluorescent 1-phenyl-2-(pyridin-2-yl)-1H-phenanthro[9,10-d]imidazole(L1)is a facile block for the construction of multichromophore organic molecules,and simultaneously serves as a chelating diimine ligand.The coordination of L1 to zinc halides enhances the intraligand charge transfer and decreases the emission energy.For the iodide derivative,intra-and intermolecular heavy atom effects lead to a dual singlet–triplet emission with a temperature-dependent ratio of fluorescence and phosphorescence bands in the crystalline state.Decoration of the anthracene core with pyridyl-phenanthroimidazole units(L2 and L3)changes the localization of the lowest energy electronic transitions to the former polyaromatic motif.The solid-state photophysical characteristics of L2 and L3-based compounds strongly depend on the intermolecular interactions between the constituting π-systems(phenanthrene and anthracene),which are perturbed by the ZnX2 coordinated fragments.Modulation of π-stacking contacts in these molecular materials containing L2 and L3 chromophores forms a basis for dynamic optical properties,responsive to mechanical,thermal,or chemical stimuli.展开更多
基金funded by Russian Science Foundation(Grant 19-73-20055-П).
文摘The idea of preparation a water-soluble Pt-containing AIEgen was successfully realized by direct reversible addition-fragmentation transfer copolymerization of a Pt(II)complex(LPtPV)containing a vinyl group and polyvinylpyrrolidone(p(VP)).The resulting block-copolymer p(VP-b-LPtPV)containing 5–8 Pt(II)chromophores exhibits intriguing photophysical properties—strong solvent and concentration dependence of absorption and emission characteristics.Various physicochemical and analytical methods(NMR spectroscopy,XRD analysis,ESI-MS,AUC,DLS,ICP-OES,GPC,viscometry,TEM)were used to characterize the initial complex,its binuclear analogs,p(VP)and p(VP-b-LPtPV).The obtained data indicate that the photophysical properties of the latter are dictated by the type of aggregation process rather than solvatochromic effects.It is shown that at low concentration in organic solvents,the platinum chromophores aggregation is either absent(dimethylformamide)or occurs predominantly at intramolecular level(MeCN),whereas in aqueous media,p(VP-b-LPtPV)readily aggregates into micellar-type nanoparticles with a hydrophilic p(VP)corona and a hydrophobic Pt-containing core,in which strong intra-and intermolecular Pt⋅⋅⋅Pt and/orπ⋅⋅⋅πinteractions result in a significant red shift of absorption and emission down to 600 and 816 nm,respectively.Despite of emission shift into NIR area where emission is commonly quenched by nonradiative vibrational relaxation,an increase in the emission quantum yield occurs in complete agreement with the typical aggregation-induced emission(AIE)emitters’behavior.Quantum mechanics/molecular mechanics simulations of aggregation processes also confirm the trends in the relationship between aggregation mode and photophysical behavior,particularly,in the variations of energy gaps between the ground state of the AIEgens and their excited singlet and triplet states.
基金the Academy of Finland(decision 317903,I.O.K.,Flagship Programme,Photonics Research and Innovation PREIN,decision 320166)the Russian Science Foundation(grant 19-73-20055,J.R.S.,photophysical studies)is gratefully acknowledged.
文摘Strongly blue fluorescent 1-phenyl-2-(pyridin-2-yl)-1H-phenanthro[9,10-d]imidazole(L1)is a facile block for the construction of multichromophore organic molecules,and simultaneously serves as a chelating diimine ligand.The coordination of L1 to zinc halides enhances the intraligand charge transfer and decreases the emission energy.For the iodide derivative,intra-and intermolecular heavy atom effects lead to a dual singlet–triplet emission with a temperature-dependent ratio of fluorescence and phosphorescence bands in the crystalline state.Decoration of the anthracene core with pyridyl-phenanthroimidazole units(L2 and L3)changes the localization of the lowest energy electronic transitions to the former polyaromatic motif.The solid-state photophysical characteristics of L2 and L3-based compounds strongly depend on the intermolecular interactions between the constituting π-systems(phenanthrene and anthracene),which are perturbed by the ZnX2 coordinated fragments.Modulation of π-stacking contacts in these molecular materials containing L2 and L3 chromophores forms a basis for dynamic optical properties,responsive to mechanical,thermal,or chemical stimuli.
