The change of fluorescence emission manipulated by spin state transition attracts considerable attention owing to its potential applications in magneto-optical switching devices.Herein,we report two two-dimensional(2D...The change of fluorescence emission manipulated by spin state transition attracts considerable attention owing to its potential applications in magneto-optical switching devices.Herein,we report two two-dimensional(2D)Hofmann-type spin crossover(SCO)metal-organic frameworks(MOFs)[Fe^(Ⅱ)(PNI)_(2){Ag^(Ⅰ)(CN)_(2)}_(2)]·CHCl_(3)(3Ag·CHCl_(3))and[FeⅡ(PNI)_(2){AuⅠ(CN)_(2)}_(2)]·CHCl_(3)(3Au·CHCl_(3))based on the fluorescent ligand N-(4-pyridylmethyl)-1,8-naphthalimide(PNI).Both complexes exhibit interesting SCO behaviors switched by guest solvent molecules,namely three-step transitions for the solvated complexes and complete onestep hysteretic SCO for the desolvated ones,verified by temperature-dependent magnetic susceptibility measurements,Mossbauer spectra,structural analyses,and differential scanning calorimetry measurements.Correspondingly,temperature-dependent fluorescence spectra exhibit double peaks(monomer and excimer emission)with both emission peaks change consistent with the change in SCO properties during the solvent molecule removal.In this study,we integrated guest-responsive SCO behavior into MOFs to manipulate the multistability of spin state and fluorescence switching,providing a rational strategy for the development of stimuli-responsive multifunctional materials.展开更多
Synergistic fluorescent spin crossover(SCO)bifunctional molecular materials have novel applications in the molecule-based magneto-optical switches.Herein,we report two novel three-dimensional(3D)Hofmann-type fluoresce...Synergistic fluorescent spin crossover(SCO)bifunctional molecular materials have novel applications in the molecule-based magneto-optical switches.Herein,we report two novel three-dimensional(3D)Hofmann-type fluorescent SCO complexes[Fe^(II)-(tppe)MI(CN)_(2)]ClO_(4)·nSolv(tppe=tetra-(4-pyridylphenyl)ethene,M=Ag(tppe-Ag),Au(tppe-Au)).Both complexes show one-step abrupt SCO with the transition temperature of 230 K for tppe-Ag,and 245 K for tppe-Au accompanied by a color change from red to light yellow.The SCO process is confirmed by the variable-temperature single-crystal X-ray diffraction analysis on tppe-Ag.For the first time,the abnormal increase in emission intensity and concomitant large bathochromic shifts in the fluorescence spectra during the SCO process are realized in the 3D Hofmann-type coordination polymers expanded by the tetradentate tppe ligand.Moreover,tppe-Ag exhibits the unprecedented fluorescence emission from green to the edge of yellow.展开更多
基金supported by the National Natural Science Foundation of China(22271171,21971142,and 22371015)Japan Society for Promotion Science(JSPS)KAKENHI(24K17698 and 24H00466)。
文摘The change of fluorescence emission manipulated by spin state transition attracts considerable attention owing to its potential applications in magneto-optical switching devices.Herein,we report two two-dimensional(2D)Hofmann-type spin crossover(SCO)metal-organic frameworks(MOFs)[Fe^(Ⅱ)(PNI)_(2){Ag^(Ⅰ)(CN)_(2)}_(2)]·CHCl_(3)(3Ag·CHCl_(3))and[FeⅡ(PNI)_(2){AuⅠ(CN)_(2)}_(2)]·CHCl_(3)(3Au·CHCl_(3))based on the fluorescent ligand N-(4-pyridylmethyl)-1,8-naphthalimide(PNI).Both complexes exhibit interesting SCO behaviors switched by guest solvent molecules,namely three-step transitions for the solvated complexes and complete onestep hysteretic SCO for the desolvated ones,verified by temperature-dependent magnetic susceptibility measurements,Mossbauer spectra,structural analyses,and differential scanning calorimetry measurements.Correspondingly,temperature-dependent fluorescence spectra exhibit double peaks(monomer and excimer emission)with both emission peaks change consistent with the change in SCO properties during the solvent molecule removal.In this study,we integrated guest-responsive SCO behavior into MOFs to manipulate the multistability of spin state and fluorescence switching,providing a rational strategy for the development of stimuli-responsive multifunctional materials.
基金supported by the National Natural Science Foundation of China(21771115,21971142)。
文摘Synergistic fluorescent spin crossover(SCO)bifunctional molecular materials have novel applications in the molecule-based magneto-optical switches.Herein,we report two novel three-dimensional(3D)Hofmann-type fluorescent SCO complexes[Fe^(II)-(tppe)MI(CN)_(2)]ClO_(4)·nSolv(tppe=tetra-(4-pyridylphenyl)ethene,M=Ag(tppe-Ag),Au(tppe-Au)).Both complexes show one-step abrupt SCO with the transition temperature of 230 K for tppe-Ag,and 245 K for tppe-Au accompanied by a color change from red to light yellow.The SCO process is confirmed by the variable-temperature single-crystal X-ray diffraction analysis on tppe-Ag.For the first time,the abnormal increase in emission intensity and concomitant large bathochromic shifts in the fluorescence spectra during the SCO process are realized in the 3D Hofmann-type coordination polymers expanded by the tetradentate tppe ligand.Moreover,tppe-Ag exhibits the unprecedented fluorescence emission from green to the edge of yellow.
