Lanthanide(Ⅲ)single-molecule magnets(SMMs)are a tool for the combination of molecular nanomagnetism with luminescent thermometry,opening the pathway not only for broadened multifunctionality but also for the optical ...Lanthanide(Ⅲ)single-molecule magnets(SMMs)are a tool for the combination of molecular nanomagnetism with luminescent thermometry,opening the pathway not only for broadened multifunctionality but also for the optical self-monitoring of temperature in SMM-based systems.Usually,this goal is realized by exploring the intrinsic properties of a single lanthanide(Ln)ion.We present an innovative strategy based on embedding magnetically anisotropic Ln(Ⅲ)centers into a red-emissive coordination system based on Eu(Ⅲ)complexes of a nonmagnetic ground state.This concept is presented for novel cyanido-bridged chains,{[LnⅢ(dppmO_(2))_(3)][AgI(CN)_(2)]}[OTf]_(2)(Ln=Eu,EuAg;Ln=Er,ErAg;Ln=Yb,YbAg;Ln=Er_(0.05)Eu_(0.95),Er@EuAg;Ln=Yb_(0.04)Eu_(0.96),Yb@EuAg;dppmO_(2)=bis(diphenylphosphino)methane dioxide;OTf=trifluoromethanesulfonate).The Ln(Ⅲ)coordination sphere,consisting of O,O-bidentate dppmO_(2) ligands occupying the equatorial positions and two axially aligned cyanido bridges,generates the distinct SMM characteristics of Er(Ⅲ)/Yb(Ⅲ)centers.Alternatively,the strong photoluminescence of Eu(Ⅲ)in EuAg exhibits pronounced thermal variation of the excitation spectrum,which is employed for ratiometric optical thermometry,revealing a relative thermal sensitivity(Sr)of up to 2.1%K^(−1) at 55 K and a good thermometric response below 110 K.The incorporation of Er(Ⅲ)/Yb(Ⅲ)centers into the Eu(Ⅲ)-based framework leads to heterotrimetallic Er@EuAg and Yb@EuAg systems,which link the SMM features with luminescent thermometry.Both physical properties are enhanced upon mixing of the Ln(Ⅲ)centers,as depicted by the slowdown of magnetic relaxation,especially for Er(Ⅲ),due to the Eu(Ⅲ)-induced weakening of the quantum tunneling of magnetization,which is accompanied by the improved thermometric response,including an increase in the maximal Sr to 3.3%K^(−1) and broadening of its operating range to 150 K,due to the structural distortion induced by Er(Ⅲ)/Yb(Ⅲ)centers.展开更多
基金the National Science Center of Poland,the OPUS-21 project(2021/41/B/ST5/02544).
文摘Lanthanide(Ⅲ)single-molecule magnets(SMMs)are a tool for the combination of molecular nanomagnetism with luminescent thermometry,opening the pathway not only for broadened multifunctionality but also for the optical self-monitoring of temperature in SMM-based systems.Usually,this goal is realized by exploring the intrinsic properties of a single lanthanide(Ln)ion.We present an innovative strategy based on embedding magnetically anisotropic Ln(Ⅲ)centers into a red-emissive coordination system based on Eu(Ⅲ)complexes of a nonmagnetic ground state.This concept is presented for novel cyanido-bridged chains,{[LnⅢ(dppmO_(2))_(3)][AgI(CN)_(2)]}[OTf]_(2)(Ln=Eu,EuAg;Ln=Er,ErAg;Ln=Yb,YbAg;Ln=Er_(0.05)Eu_(0.95),Er@EuAg;Ln=Yb_(0.04)Eu_(0.96),Yb@EuAg;dppmO_(2)=bis(diphenylphosphino)methane dioxide;OTf=trifluoromethanesulfonate).The Ln(Ⅲ)coordination sphere,consisting of O,O-bidentate dppmO_(2) ligands occupying the equatorial positions and two axially aligned cyanido bridges,generates the distinct SMM characteristics of Er(Ⅲ)/Yb(Ⅲ)centers.Alternatively,the strong photoluminescence of Eu(Ⅲ)in EuAg exhibits pronounced thermal variation of the excitation spectrum,which is employed for ratiometric optical thermometry,revealing a relative thermal sensitivity(Sr)of up to 2.1%K^(−1) at 55 K and a good thermometric response below 110 K.The incorporation of Er(Ⅲ)/Yb(Ⅲ)centers into the Eu(Ⅲ)-based framework leads to heterotrimetallic Er@EuAg and Yb@EuAg systems,which link the SMM features with luminescent thermometry.Both physical properties are enhanced upon mixing of the Ln(Ⅲ)centers,as depicted by the slowdown of magnetic relaxation,especially for Er(Ⅲ),due to the Eu(Ⅲ)-induced weakening of the quantum tunneling of magnetization,which is accompanied by the improved thermometric response,including an increase in the maximal Sr to 3.3%K^(−1) and broadening of its operating range to 150 K,due to the structural distortion induced by Er(Ⅲ)/Yb(Ⅲ)centers.
