The fast switching feature of spontaneous polarization(Ps)is one of the basis for ferroelectric applications in the field of data storage.However,most molecular ferroelectrics exhibit low operating performance in pola...The fast switching feature of spontaneous polarization(Ps)is one of the basis for ferroelectric applications in the field of data storage.However,most molecular ferroelectrics exhibit low operating performance in polarization switching.Herein,we report fast switching Ps(25 kHz,293 K)and low coercive field(0.55 kV cm^(-1),353 K)for a microporous structural molecular rotor ferroelectric[CdL_(4)]^(2+)[NO_(3)^(-)]_(2)(L=β-alanine).In particular,the high switching frequency of P_(s) remains steady with high operational cycles(4.66×10^(7)).Single-crystal structures analysis and density functional theory(DFT)calculations reveal the fast switching of Ps originating from the fast static-rotating-static process of NO_(3)^(-).This molecular rotor-type ferroelectric material provides more possibilities to develop next-generation non-volatile memory devices.展开更多
Photoresponsive spin-crossover(SCO)compounds are particularly appealing due to precise adjustability of light wavelength/energy and the capability for remote switching.Herein,we introduce the 3-styrylpyridine(3-spy)li...Photoresponsive spin-crossover(SCO)compounds are particularly appealing due to precise adjustability of light wavelength/energy and the capability for remote switching.Herein,we introduce the 3-styrylpyridine(3-spy)ligand into a 2D Fe(II)-Ag(I)bimetallic Hofmann-type framework to construct a photoresponsive SCO compound[Fe(3-spy)_(2){Ag(CN)_(2)}_(2)](1).Upon irradiation at 365 nm,the criss-cross CC double bonds of 3-spy ligands in 1 undergo a pedal-like conformational motion and a photochemical[2+2]cycloaddition reaction,leading to structural disorder but resulting in a more regular coordination geometry around the SCO center in the cyclobutane product[Fe(hh-rctt-1,2-ppcb){Ag(CN)_(2)}_(2)](2)(hh-rctt-1,2-ppcb=hh-rctt-1,2-bis(3-pyridyl)-3,4-bis(phenyl)cyclobutane,r=reference group,c=cis and t=trans,hh=head-to-head).These structural changes exert opposite influences on SCO cooperativity and the ligand field of the SCO center.Studies of SCO behavior under different irradiation times revealed that the SCO cooperative behavior gradually shifts from a two-step SCO in 1 to an incomplete and gradual one-step SCO in 2.Notably,T_(1/2),which represents the intermediate spin state whereγHS=0.5,remains almost unchanged,indicating that only the SCO cooperativity is significantly modulated in this unique photochemical[2+2]reaction-integrated SCO system.Moreover,upon irradiation at 254 nm,partial stereoselective cleavage of the cyclobutane moieties in 2 was observed,suggesting the potential for constructing photoswitchable SCO materials.展开更多
基金the support from the National Natural Science Foundation of China(Grant No.11834002)the support from the National Natural Science Foundation of China(Grant No.22175079)+3 种基金the support from the National Natural Science Foundation of China(Grant No.22205087)Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry(Grant No.20212BCD42018)the support from the National Natural Science Foundation of China(Grant No.21875093)the Natural Science Foundation of Jiangxi Province(Grant No.20204BCJ22015 and 20202ACBL203001).
文摘The fast switching feature of spontaneous polarization(Ps)is one of the basis for ferroelectric applications in the field of data storage.However,most molecular ferroelectrics exhibit low operating performance in polarization switching.Herein,we report fast switching Ps(25 kHz,293 K)and low coercive field(0.55 kV cm^(-1),353 K)for a microporous structural molecular rotor ferroelectric[CdL_(4)]^(2+)[NO_(3)^(-)]_(2)(L=β-alanine).In particular,the high switching frequency of P_(s) remains steady with high operational cycles(4.66×10^(7)).Single-crystal structures analysis and density functional theory(DFT)calculations reveal the fast switching of Ps originating from the fast static-rotating-static process of NO_(3)^(-).This molecular rotor-type ferroelectric material provides more possibilities to develop next-generation non-volatile memory devices.
基金supported by the NSFC(21801258,22461018,22488101)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23ptpy73)the Science and Technology Program of Guangzhou,China(2024A04J4433).
文摘Photoresponsive spin-crossover(SCO)compounds are particularly appealing due to precise adjustability of light wavelength/energy and the capability for remote switching.Herein,we introduce the 3-styrylpyridine(3-spy)ligand into a 2D Fe(II)-Ag(I)bimetallic Hofmann-type framework to construct a photoresponsive SCO compound[Fe(3-spy)_(2){Ag(CN)_(2)}_(2)](1).Upon irradiation at 365 nm,the criss-cross CC double bonds of 3-spy ligands in 1 undergo a pedal-like conformational motion and a photochemical[2+2]cycloaddition reaction,leading to structural disorder but resulting in a more regular coordination geometry around the SCO center in the cyclobutane product[Fe(hh-rctt-1,2-ppcb){Ag(CN)_(2)}_(2)](2)(hh-rctt-1,2-ppcb=hh-rctt-1,2-bis(3-pyridyl)-3,4-bis(phenyl)cyclobutane,r=reference group,c=cis and t=trans,hh=head-to-head).These structural changes exert opposite influences on SCO cooperativity and the ligand field of the SCO center.Studies of SCO behavior under different irradiation times revealed that the SCO cooperative behavior gradually shifts from a two-step SCO in 1 to an incomplete and gradual one-step SCO in 2.Notably,T_(1/2),which represents the intermediate spin state whereγHS=0.5,remains almost unchanged,indicating that only the SCO cooperativity is significantly modulated in this unique photochemical[2+2]reaction-integrated SCO system.Moreover,upon irradiation at 254 nm,partial stereoselective cleavage of the cyclobutane moieties in 2 was observed,suggesting the potential for constructing photoswitchable SCO materials.
