Transducing thermal energy into mechanical movements via molecular reconfigurations offers a cutting-edge approach to thermal actuating materials,which could be applied to sensors,energy harvesting and storage devices...Transducing thermal energy into mechanical movements via molecular reconfigurations offers a cutting-edge approach to thermal actuating materials,which could be applied to sensors,energy harvesting and storage devices[1].Thermal expansion is a pivotal aspect in solid state chemistry,intricately intertwined with various factors such as crystal structure,chemical composition,electronic configuration,microstructure,and defects.Most materials undergo isotropic and positive thermal expansion(PTE)because of the disharmonic vibrational amplitudes of their chemical bonds.Moreover,anisotropic thermal expansion(ATE)and negative thermal expansion(NTE)are fascinating physical attributes of solids,which can originate from electronic or magnetic mechanisms,as well as through a transverse phonon mechanism in insulating lattice solids.展开更多
The spin crossover（SCO） compound [Fe（bapbpy）（NCS）2],where bapbpy contains two fused N,N-bis（2-pyridyl）amines,has been studied by DFT/TD-DFT/BS-DFT methods.Several density functionals and basis sets were used i...The spin crossover（SCO） compound [Fe（bapbpy）（NCS）2],where bapbpy contains two fused N,N-bis（2-pyridyl）amines,has been studied by DFT/TD-DFT/BS-DFT methods.Several density functionals and basis sets were used in the calculation to obtain optimized geometries of the compound in the low-（LS） and high-spin（HS） states.The vibrational modes and IR spectra,spin splitting energies,excited states and UV/Vis absorption spectra were obtained.The structural parameters of the calculated isolated complex are in good agreement with the X-ray data.We investigate three dimers of [Fe（bapbpy）（NCS）2] complex for their magnetic properties.It has been found that the complex（1,3） has ferromagnetic character while the others are antiferromagnetic in nature by using a broken symmetry approach in the DFT framework（BS-DFT） with support from the coupling constant values（J） and spin density plots.展开更多
Luminescent spin crossover(SCO) materials have attracted significant interest owing to their potential applications in magneto-optical switches. However, the majority of previously reported FeII-based SCO complexes ar...Luminescent spin crossover(SCO) materials have attracted significant interest owing to their potential applications in magneto-optical switches. However, the majority of previously reported FeII-based SCO complexes are adversely affected by fluorescence quenching in the solid-state. Here, we have constructed the first mononuclear FeIIcomplex decorated with an aggregation-induced emission(AIE) luminophore(i.e., tetraphenylethylene) that exhibits synergistic SCO and fluorescence behavior. Intriguingly, we obtained two types of crystals in different solvent systems, both displaying distinct magnetic bistability and fluorescence properties. The fluorescence intensity was observed to track the magnetic susceptibility, which confirmed that SCO and solid-state fluorescence operate synergistically. We introduce a novel approach for the construction of luminescent SCO compounds using an AIEgen as a luminophore, which leads to fluorescence emission in the solid-state, thus allowing us to study the synergy between SCO and fluorescence.展开更多
Three iron （III） complexes with the formula of [Feat（X）L2]BPh4 were studied, in which a pentadentate Schiff-base ligand （H2L2 = bis （3-methoxysalicylideneiminopropyl） methylamine） and a counter anion BPh4 were...Three iron （III） complexes with the formula of [Feat（X）L2]BPh4 were studied, in which a pentadentate Schiff-base ligand （H2L2 = bis （3-methoxysalicylideneiminopropyl） methylamine） and a counter anion BPh4 were fixed, and three monodentate ligands, 3-Mepy （3-methylpyridine）, 4-NH2py （4-aminopyridine）, and 2-Meim （2-methylimidazole） were used as the axial ligand X. The temperature dependence of magnetic susceptibility measurements demonstrated that [Fem（3-Mepy）L2]BPh4 showed a gradual spin equilibrium between HS （high-spin） （S = 5/2） and LS （low-spin） （S = 1/2） states, [Fem（4-NH2py）L2]BPh4 showed a steep SCO （spin crossover） and [FeIH（2-Melm）L2]BPh4 was in the HS state even at 100 K. The single crystal X-ray analyses demonstrated that [FelH（4-NH2py）L2]BPh4 has an one-dimensional chain structure constructed by intermolecular hydrogen bonding between 4-amino group of 4-NH2py and methoxy oxygen of adjacent molecular-cation. The crystal structure of [FenI（3-Mepy）L2]BPh4 has no such intermolecular interaction and its SCO site behaves independently, and the crystal structure of [FeIII（2-Meim）L2]BPh4 has a NH...n interaction between imidazole group of 2-Meim of cation and a phenyl group of anion BPh4. The result demonstrates that the intermolecular hydrogen bonding affects SCO profile significantly.展开更多
Designing and implementing multielectron transfer and single-molecule magnet properties in spin crossover compounds constitute a promising way to obtain a new class of multiresponsive and multifunctional materials.Thi...Designing and implementing multielectron transfer and single-molecule magnet properties in spin crossover compounds constitute a promising way to obtain a new class of multiresponsive and multifunctional materials.This contribution uses N-phenyl-substituted pyridine-2,6-diimine(PDI)ligands to explore a novel family of spin-crossover cobalt(Ⅱ)complexes,with general formula[CoL_(2)](ClO_(4))_(2)·xH_(2)O[L=4-MePhPDI(1,x=1),4-MeOPhPDI(2,x=0),4-MeSPhPDI(3,x=0),4-Me_(2)NPhPDI(4,x=0.5),and 2,4-Me_(2)PhPDI(5,x=0)].These mononuclear six-coordinate octahedral cobalt(Ⅱ)bis(chelating)complexes incorporate tridentate PDI derivatives with various electron-donating substituents at para(X_(4)=Me,OMe,SMe,and Me_(2)N)or ortho and para positions(X_(2),X_(4)=Me)of terminal phenyl rings.Our investigations reveal that these complexes exhibit both thermally-induced low-spin(LS)/high-spin(HS)transition and field-induced slow magnetic relaxation in the LS(S=1/2)and HS(S=3/2)states.Moreover,they display a dual multiredox behaviour featuring one-electron oxidation of the paramagnetic Co^(Ⅱ)ion to the diamagnetic Co^(Ⅲ)ion and stepwise two-electron reduction of each PDI ligand to the corresponding imine-type PDI·−π-radical anion and diimine-type PDI^(2−)dianion,which positions them as candidates for prototypes of spin quantum transistors and capacitors,offering potential applications in quantum information processing.展开更多
Thermal desolvation is a very attractive method for the post-synthetic modification of the physicochemical properties of switchable materials.In this field of research,special attention has been paid to the possibilit...Thermal desolvation is a very attractive method for the post-synthetic modification of the physicochemical properties of switchable materials.In this field of research,special attention has been paid to the possibility of modifying the thermo-and photo-induced spin crossover(SCO)properties of metal complexes as they can act as solvent sensors.Two new[Fe(3-bpp)_(2)](ClO_(4))_(2)·2.5H_(2)O·MeOH(1·sol)and[Fe(3-bpp)_(2)](ReO_(4))_(2)·3H_(2)O(_(2)·sol)compounds.展开更多
The literature tetradentate acyclic Schiff base ligand HL^(H-OH)(from the 2:1 reaction of pyridine-2-carboxylaldehyde with 1,3-diamino-2-propanol)was alkylated using a range of 1-bromoalkanes varying in length,BrR(R=C...The literature tetradentate acyclic Schiff base ligand HL^(H-OH)(from the 2:1 reaction of pyridine-2-carboxylaldehyde with 1,3-diamino-2-propanol)was alkylated using a range of 1-bromoalkanes varying in length,BrR(R=C_(10)H_(21),C_(16)H_(33),C_(18)H_(37),C_(20)H_(41)and C_(22)H_(45))to yield five new ligands,LH-OR.The synthesis,magnetic and Langmuir characteristics of the corresponding family of six neutral mononuclear Fe(II)complexes,the parent complex[FeII(HLH-OH)(NCBH_(3))_(2)]and the five alkylated ligand derivatives[Fe^(II)(L_(H-OR))(NCBH_(3))_(2)],is detailed.The solution spin crossover temperature,T_(12),can be tuned by two methods:(a)increasing the solvent polarity index(P’)from 5 to 7 increases T_(12)by 172 K,whereas(b)increasing the tail length from C_(10)to C_(22)decreases T_(12)by 115 K.In both cases strong linear correlations are observed,so both of these,choice of solvent(R^(2)=0.99,albeit only for three solvents)and of tail length(R^(2)=0.98,for five complexes),are levers for the predictable tuning of the spin state in advance of synthesis.The compounds with longer tails,C_(18),C_(20)and C_(22),showed a small window of thermal hysteresis(<5 K)in D_(3)-acetonitrile solution.Water solubility hampered the formation of Langmuir films of these complexes.But the use of a 1:1 mixture of stearic acid with[Fe^(II)(LH-OC_(18))(NCBH_(3))_(2)]facilitated the formation of a stable Langmuir film,a monolayer of which was transferred onto a quartz slide:multi-layering was not possible.展开更多
A precise regulation of the temperature of spin crossover(SCO)is an essential task to envisage practical applications of switchable materials.Here,we present three isostructural complexes with the formula[Fe(LCl)(NCE)...A precise regulation of the temperature of spin crossover(SCO)is an essential task to envisage practical applications of switchable materials.Here,we present three isostructural complexes with the formula[Fe(LCl)(NCE)_(2)],where LCl is the tetradentate ligand N,N′-bis[(4-chloro-2-pyridyl)methyl]ethane-1,2-diamine and E=S(1-S),Se(1-Se),and BH_(3)(1-BH_(3)).展开更多
The pursuit of spin crossover(SCO)materials with photoswitchable multistability is driven by fascinating perspectives toward light-response switches and opto-magnetic memory devices.Herein,we report a 3D Hofmann-type ...The pursuit of spin crossover(SCO)materials with photoswitchable multistability is driven by fascinating perspectives toward light-response switches and opto-magnetic memory devices.Herein,we report a 3D Hofmann-type metal–organic framework[Fe(bpn){Ag(CN)_(2)}_(2)]·1.5(Fnaph)(bpn=1,4-di(pyridin-4-yl)naphthalene,Fnaph=1-fluoronaphthalene),which displays an incomplete two-step SCO behaviour.The asymmetric host–vip interactions induce an intermediate HS–LS state at low temperature.Photomagnetic measurements exhibited an extremely rare bidirectional light-induced excited spin-state trapping(LIESST)effect with green and near-IR light irradiation,in which both metastable HS*and hidden LS*states were revealed at 10 K.The light-induced tristability paves the way for designing optomagnetic memory devices.展开更多
Spin crossover(SCO)compounds are bistable in nature but can exhibit five main types of SCO behaviors as collective phenomena.Here,incomplete,gradual,step,abrupt and hysteretic types of SCO behaviors can be observed in...Spin crossover(SCO)compounds are bistable in nature but can exhibit five main types of SCO behaviors as collective phenomena.Here,incomplete,gradual,step,abrupt and hysteretic types of SCO behaviors can be observed in the magnetic curve of a 3D Hofmann-type metal–organic framework[Fe(dpt){Pt(CN)_(4)}]·dpt·2.5H_(2)O(1·dpt·2.5H_(2)O,dpt=2,5-di(pyridine-4-yl)thiophene).It hints that the variable-temperature spin transition process can be more complicated than thus far anticipated.Meanwhile,two-and three-step SCO behaviors are displayed for the partially and fully dehydrated phases 1·dpt·1.5H_(2)O and 1·dpt,respectively.Reversible SCO modulations are further proved by water adsorption.The magnetostructural corrections suggest that SCO behaviors can even be tuned by the weak host–vip hydrogenbonding interactions,which provides great opportunities to design chemosensors.展开更多
We report the unprecedented observation of reversible interface propagation in the switchable cooperative Fe(Ⅲ)spin crossover compound[Fe(3-EtO-salEen)_(2)]NO_(3),where 3-EtO-salEen is 3-ethoxy-N-ethyl-N-(2-aminoethy...We report the unprecedented observation of reversible interface propagation in the switchable cooperative Fe(Ⅲ)spin crossover compound[Fe(3-EtO-salEen)_(2)]NO_(3),where 3-EtO-salEen is 3-ethoxy-N-ethyl-N-(2-aminoethyl)salicylaldiminate.This complex exhibits a spin transition from low-spin to high-spin states,triggered by temperature around 345 K.Magnetic susceptibility measurements reveal an abrupt transition with a thermal hysteresis of 5 K.Differential scanning calorimetry confirms both endothermic(T_(on)=344.50 K and T_(max)=345.61 K,Δ_(trs)H°_(m)=12:05 kJ mol^(-1)andΔ_(trs)S°_(m)=34:98 J mol^(-1))and exothermic(T_(on)=344.40 K,T_(max)=345.49 K,Δ_(trs)H°_(m)=10:98 kJ mol^(-1)andΔ_(trs)S°_(m)=31:88 J mol^(-1))peaks corresponding to the spin transition temperatures.Cryogenic optical microscopy reveals rapid interface propagation,with velocities(v_(HS→LS)≃1672μm s^(−1)and v_(LS→HS)≃850μm s^(−1))significantly higher than those observed in traditional Fe(II)-based spin crossover materials.The high-speed propagation is attributed to the combined effect of the reduced volume change and lower elastic energy barriers associated with the transition in Fe(Ⅲ)systems and the high values of the transition temperatures.Hirshfeld surface analysis reveals that the cooperative nature of the transition is influenced by non-conventional hydrogen bonding andπ-πinteractions.This study represents the first report of reversible interface propagation in Fe(Ⅲ)complexes,providing valuable insights into the fundamental mechanisms that govern spin crossover transitions in these systems.展开更多
Four new bidentate 5-(Z-pyridine)-4-(4-methyl-phenyl)-3-phenyl-1,2,4-triazole ligands L^(pytZ)(meta-Z=CF_(3),Br,F,Me)and the corresponding family of[Fe^(II)(L^(pytZ))_(2)(NCBH_(3))_(2)]complexes,in addition to the lit...Four new bidentate 5-(Z-pyridine)-4-(4-methyl-phenyl)-3-phenyl-1,2,4-triazole ligands L^(pytZ)(meta-Z=CF_(3),Br,F,Me)and the corresponding family of[Fe^(II)(L^(pytZ))_(2)(NCBH_(3))_(2)]complexes,in addition to the literature unsubstituted analogue[Fe^(II)(L^(pytH))_(2)(NCBH_(3))_(2)],are prepared and studied herein.Single crystal structure determinations on all four new complexes confirmed the expected octahedral coordination,with trans-NCBH_(3)co-ligands.Solid-state variable temperature magnetic studies of air-dried crystals showed that[Fe^(II)(LpytCF_(3))_(2)(NCBH_(3))_(2)]is SCO active with a hysteresis loop at 208 K(T_(1/2)↓=203 K,T_(1/2)↑=213 K;ΔT_(1/2)=10 K);[Fe^(II)(LpytBr)_(2)(NCBH_(3))_(2)]is not SCO active until heated above RT,while[Fe^(II)(L^(pytF))_(2)(NCBH_(3))_(2)]and[Fe^(II)(L^(pytMe))2(NCBH_(3))_(2)]are SCO active close to RT(T_(1/2)=290 and 300 K respectively).Solution phase variable temperature Evans NMR method studies in CDCl_(3)showed that four of the complexes were SCO active close to RT(T_(1/2)=279-294 K)whilst[Fe^(II)(LpytCF_(3))_(2)(NCBH_(3))_(2)]was mostly LS at RT(T_(1/2)∼374 K).These solution phase T_(1/2)values,and those for four literature families of bi-(five Lazine),tri-(fourteen bppX,Y,twelve pyboxX)or tetra-dentate(seven pytacnX)ligands,which feature para(X)pyridine or meta(Y)pyrazole ring substituents,are used,along with the calculated^(15)N NMR chemical shift of the coordinating azine/azole nitrogen(N_(A))in the ligand(for all forty-two ligands;using a refined protocol),to test the generality of the previously reported correlation ofδN_(A)chemical shift in the free ligand with the solution T_(1/2)for the respective iron(II)complex.Moderately good to excellent correlations ofδN_(A)with T_(1/2)were observed for each of the ligand families with a para substituent(R^(2)=0.69-0.96),whereas there is no correlation when meta substituents are modified(R^(2)=0.15-0.37),probably because the electronic impact of this is too small.Finally,δNA also shows promise as an easily calculated measure of the electronic effect of any substituent,in contrast to the Hammett constant(σp^(+))which is not available for all possible substituents.展开更多
Spin crossover frameworks and molecular crystals display fascinating collective behaviours.This includes multi-step transitions with hysteresis and a wide variety of long-range ordered patterns of high-spin and low-sp...Spin crossover frameworks and molecular crystals display fascinating collective behaviours.This includes multi-step transitions with hysteresis and a wide variety of long-range ordered patterns of high-spin and low-spin metal centres.From both practical and fundamental perspectives it is important to understand the mechanisms behind these collective behaviours.We study a simple model of elastic interactions and identify thirty six different spin-state ordered phases.We observe spin-state transitions with between one and eight steps.These include both sharp transitions and crossovers,and both complete and incomplete spin crossover.We demonstrate structure–property relationships that explain these differences.These arise because through-bond interactions are antiferroelastic(favour metal centres with different spinstates);whereas,through-space interactions are typically ferroelastic(favour the same spin-state).In general,rigid materials with longer range elastic interactions lead to transitions with more steps and more diverse spin-state ordering,which explains why both are prominent in frameworks.展开更多
The assembly of molecules simultaneously exhibiting slow magnetic relaxation and spin crossover(SCO)behaviors at the molecular level is a fascinating challenge for chemists.The synthesis strategy of combining 3d and 4...The assembly of molecules simultaneously exhibiting slow magnetic relaxation and spin crossover(SCO)behaviors at the molecular level is a fascinating challenge for chemists.The synthesis strategy of combining 3d and 4f ions in a molecule is a very promising route to a dual magnetic system.With this goal in mind,a series of mixed-metal structures,namely[Dy_(2)Fe_(2)(H_(2)L)_(4)(OH)_(6)](NO_(3))_(4)·12CH_(3)OH·6H_(2)O(1),[Dy_(2)Fe_(2)(H_(2)L)_(4)(OH)_(6)]Cl_(4)·2CH_(3)OH·20H_(2)O(2),[Dy_(2)Fe_(2)(H_(2)L)_(4)(OH)_(6)]Cl_(4)·4CH_(3)OH·20H_(2)O(3)and[Dy_(2)Fe_(2)(H_(2)L)_(4)(NO_(3))_(3)CH_(3)O](NO_(3))_(5)(CF_(3)SO_(3))·6CH_(3)OH·H_(2)O(4)containing a versatile Schiff-base ligand N’-((E)-pyridin-2-ylmethylene)-6-(2-((E)-pyridin-2-ylmethylene)hydrazinyl)nicotinohydrazide(H_(2)L),have been synthesized and characterized.Alternating current(ac)susceptibility measurements reveal that complexes 1-4 exhibit a slow magnetic relaxation behavior.More importantly,complexes 2 and 3 exhibit one-and two-step SCO behaviors,respectively.To our knowledge,this is the first report on 3d-4f structures that exhibit the dual function of slow magnetic relaxation and SCO behaviors to date.展开更多
In the perspective of elaborating functional devices based on inorganic molecular materials,it is important not only to continue research on their synthesis and to understand their properties but also to develop new s...In the perspective of elaborating functional devices based on inorganic molecular materials,it is important not only to continue research on their synthesis and to understand their properties but also to develop new strategies for their processing and shaping.In this context,we show here that centimeter-scale materials exhibiting solid state-like spin-crossover(SCO)properties and easy handling under ambient conditions can be obtained that preserve their thermochromic properties over months.Combining a triazole-based Fe(II)SCO compound with functionalized silica nanoparticles gives rise to nanocomposite soft gels.These gels were used as templates for the formation of a flexible macroporous hybrid silica network via a vapor phase sol–gel process.Further coating with PDMS provided both long-term protection of the material against drying and operationality in aqueous media.Our approach offers new hopes for the development of optical and magnetic devices based on SCO coordination polymers.展开更多
Identifying and quantifying the individual factors affecting the temperature and properties of the spin crossover in transition metal complexes is a challenging task,because many variables are involved.While the most ...Identifying and quantifying the individual factors affecting the temperature and properties of the spin crossover in transition metal complexes is a challenging task,because many variables are involved.While the most decisive factor is the crystal field imparted by ligands around the active metal center,some less common actors are intramolecular steric repulsions or non-covalent interactions.展开更多
Spin crossover(SCO)compounds are versatile platforms for incorporating functional ligands,enabling profuse magnetic regulating strategies and providing new likelihood for diversified practical applications of magneto-...Spin crossover(SCO)compounds are versatile platforms for incorporating functional ligands,enabling profuse magnetic regulating strategies and providing new likelihood for diversified practical applications of magneto-switches and information storage devices.Among the copious choices for stimuli-responsive ligands,diarylethene stands out as a photochromic unit that can be integrated into magnetic materials.Here,we report a triple interpenetrating SCO framework[Fe^(II)(Lo)_(2){Ag(CN)_(2)}_(2){Ag(CN)}_(2)](1,Lo=1,2-bis(2-methyl-5-(pyridin-4-yl)thiophen-3-yl)cyclopent-1-ene)with heterometallic nodes.Distinct from the conventional SCO frameworks in which Fe^(II) centers are directly bridged by organic ligands,the coordination fashion in 1 is manifested as Fe^(II)-Lo-Ag^(I)-Lo-Fe^(II).Photochromism is partially realized by the alternation of 365 nm and 520 nm light irradiation due to the tightly packed lattice.Subtle magnetic switching is observed from 1 to 1^(UV).Moreover,1^(UV) displays a photothermal response up to 162℃ under 808 nm light irradiation,with an enhancement in the photothermal conversion efficiency compared with that of 1.This thermally stable three-dimensional framework provides new structural possibilities for SCO polymers and takes a step forward in the assembly of UV-Vis-NIR responsive magnetic materials.展开更多
Using a self-assembly process involving a[Mo^(Ⅲ)(CN)_(7)]^(4−)unit,an Fe^(Ⅱ) ion,and a 1,4-bis(4H-1,2,4-triazol-4-yl)benzene(btb)ligand,we have synthesized a novel coordination polymer,denoted as{K_(2)Fe^(Ⅱ)(btb)[M...Using a self-assembly process involving a[Mo^(Ⅲ)(CN)_(7)]^(4−)unit,an Fe^(Ⅱ) ion,and a 1,4-bis(4H-1,2,4-triazol-4-yl)benzene(btb)ligand,we have synthesized a novel coordination polymer,denoted as{K_(2)Fe^(Ⅱ)(btb)[Mo^(Ⅲ)(CN)_(7)]·5H_(2)O}n(1).Single-crystal structure analysis revealed a three-dimensional(3D)Hofmann-type framework for compound 1.The[Mo^(Ⅲ)(CN)_(7)]^(4−)unit engaged four cyanide groups to coordinate with Fe^(Ⅱ) ions,creating an anionic two-dimensional(2D)cyano-bridged layer of{Fe^(Ⅱ)[Mo^(Ⅲ)(CN)_(7)]}_(n).The btb ligands,in turn,coordinated axially with the Fe^(Ⅱ) ions,bridging adjacent 2D layers and thus constructing a 3D framework.Magnetic studies have shown that compound 1 exhibits a hysteretic one-step spin-crossover behavior.Moreover,a ferrimagnetic ordering with a critical temperature of approximately 65 K was also observed,which may be ascribed to the compound’s“core-shell”architecture:the main core is responsible for the SCO behavior,while the shell contributes to the ferrimagnetic characteristics.To the best of our knowledge,this is the first observation of spin-crossover behavior in compounds based on the[Mo^(Ⅲ)(CN)_(7)]^(4−)unit.展开更多
An azo-based ligand of azotetrazolyl-2,7-dihydroxynaphthalene(H3ATD)was used to synthesize three unprecedented Fe^(Ⅲ)-M^(Ⅱ)-Fe^(Ⅲ)(M=Fe,Cd)linear trinuclear complexes with different high temperature spin crossover(...An azo-based ligand of azotetrazolyl-2,7-dihydroxynaphthalene(H3ATD)was used to synthesize three unprecedented Fe^(Ⅲ)-M^(Ⅱ)-Fe^(Ⅲ)(M=Fe,Cd)linear trinuclear complexes with different high temperature spin crossover(SCO)behaviours for the terminal Fe^(Ⅲ)ions.展开更多
The authors regret that there were some errors in the original article.In the first paragraph of the Synthesis section in the Experimental section,in the sentence beginning“A 5 mL vial containing…”,the quantity of ...The authors regret that there were some errors in the original article.In the first paragraph of the Synthesis section in the Experimental section,in the sentence beginning“A 5 mL vial containing…”,the quantity of L_(o) was incorrectly given as“0.05 mmol,10.3 mg”.This should be“0.05 mmol,20.7 mg”.展开更多
基金supported by the National Natural Science Foundation of China(22171155)Natural Science Foundation of Shandong Province(ZR2022YQ07)Taishan Scholar Program(tsqn202306166).
文摘Transducing thermal energy into mechanical movements via molecular reconfigurations offers a cutting-edge approach to thermal actuating materials,which could be applied to sensors,energy harvesting and storage devices[1].Thermal expansion is a pivotal aspect in solid state chemistry,intricately intertwined with various factors such as crystal structure,chemical composition,electronic configuration,microstructure,and defects.Most materials undergo isotropic and positive thermal expansion(PTE)because of the disharmonic vibrational amplitudes of their chemical bonds.Moreover,anisotropic thermal expansion(ATE)and negative thermal expansion(NTE)are fascinating physical attributes of solids,which can originate from electronic or magnetic mechanisms,as well as through a transverse phonon mechanism in insulating lattice solids.
基金Supported by the Natural Science Foundation of Shandong Province(No.Y2006B43)
文摘The spin crossover（SCO） compound [Fe（bapbpy）（NCS）2],where bapbpy contains two fused N,N-bis（2-pyridyl）amines,has been studied by DFT/TD-DFT/BS-DFT methods.Several density functionals and basis sets were used in the calculation to obtain optimized geometries of the compound in the low-（LS） and high-spin（HS） states.The vibrational modes and IR spectra,spin splitting energies,excited states and UV/Vis absorption spectra were obtained.The structural parameters of the calculated isolated complex are in good agreement with the X-ray data.We investigate three dimers of [Fe（bapbpy）（NCS）2] complex for their magnetic properties.It has been found that the complex（1,3） has ferromagnetic character while the others are antiferromagnetic in nature by using a broken symmetry approach in the DFT framework（BS-DFT） with support from the coupling constant values（J） and spin density plots.
基金Nankai University for the startup funds in support of young talented researcherssupported by the National Natural Science Foundation of China(NSFC, Nos. 21971124, 22035003)。
文摘Luminescent spin crossover(SCO) materials have attracted significant interest owing to their potential applications in magneto-optical switches. However, the majority of previously reported FeII-based SCO complexes are adversely affected by fluorescence quenching in the solid-state. Here, we have constructed the first mononuclear FeIIcomplex decorated with an aggregation-induced emission(AIE) luminophore(i.e., tetraphenylethylene) that exhibits synergistic SCO and fluorescence behavior. Intriguingly, we obtained two types of crystals in different solvent systems, both displaying distinct magnetic bistability and fluorescence properties. The fluorescence intensity was observed to track the magnetic susceptibility, which confirmed that SCO and solid-state fluorescence operate synergistically. We introduce a novel approach for the construction of luminescent SCO compounds using an AIEgen as a luminophore, which leads to fluorescence emission in the solid-state, thus allowing us to study the synergy between SCO and fluorescence.
文摘Three iron （III） complexes with the formula of [Feat（X）L2]BPh4 were studied, in which a pentadentate Schiff-base ligand （H2L2 = bis （3-methoxysalicylideneiminopropyl） methylamine） and a counter anion BPh4 were fixed, and three monodentate ligands, 3-Mepy （3-methylpyridine）, 4-NH2py （4-aminopyridine）, and 2-Meim （2-methylimidazole） were used as the axial ligand X. The temperature dependence of magnetic susceptibility measurements demonstrated that [Fem（3-Mepy）L2]BPh4 showed a gradual spin equilibrium between HS （high-spin） （S = 5/2） and LS （low-spin） （S = 1/2） states, [Fem（4-NH2py）L2]BPh4 showed a steep SCO （spin crossover） and [FeIH（2-Melm）L2]BPh4 was in the HS state even at 100 K. The single crystal X-ray analyses demonstrated that [FelH（4-NH2py）L2]BPh4 has an one-dimensional chain structure constructed by intermolecular hydrogen bonding between 4-amino group of 4-NH2py and methoxy oxygen of adjacent molecular-cation. The crystal structure of [FenI（3-Mepy）L2]BPh4 has no such intermolecular interaction and its SCO site behaves independently, and the crystal structure of [FeIII（2-Meim）L2]BPh4 has a NH...n interaction between imidazole group of 2-Meim of cation and a phenyl group of anion BPh4. The result demonstrates that the intermolecular hydrogen bonding affects SCO profile significantly.
基金supported by the Spanish MINECO(Projects PID2019-109735GB-I00Unidad de Excelencia María de Maeztu CEX2019-000919-M)+2 种基金the Generalitat Valenciana(AICO/2020/183 and AICO/2021/295)funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no 748921-SIMOF.R.R.thanks the Generalitat Valenciana and CAPES/BRASIL for the doctoral(GRISOLIAP/2017/057)postdoctoral(88887.798611/2022-00)grants。
文摘Designing and implementing multielectron transfer and single-molecule magnet properties in spin crossover compounds constitute a promising way to obtain a new class of multiresponsive and multifunctional materials.This contribution uses N-phenyl-substituted pyridine-2,6-diimine(PDI)ligands to explore a novel family of spin-crossover cobalt(Ⅱ)complexes,with general formula[CoL_(2)](ClO_(4))_(2)·xH_(2)O[L=4-MePhPDI(1,x=1),4-MeOPhPDI(2,x=0),4-MeSPhPDI(3,x=0),4-Me_(2)NPhPDI(4,x=0.5),and 2,4-Me_(2)PhPDI(5,x=0)].These mononuclear six-coordinate octahedral cobalt(Ⅱ)bis(chelating)complexes incorporate tridentate PDI derivatives with various electron-donating substituents at para(X_(4)=Me,OMe,SMe,and Me_(2)N)or ortho and para positions(X_(2),X_(4)=Me)of terminal phenyl rings.Our investigations reveal that these complexes exhibit both thermally-induced low-spin(LS)/high-spin(HS)transition and field-induced slow magnetic relaxation in the LS(S=1/2)and HS(S=3/2)states.Moreover,they display a dual multiredox behaviour featuring one-electron oxidation of the paramagnetic Co^(Ⅱ)ion to the diamagnetic Co^(Ⅲ)ion and stepwise two-electron reduction of each PDI ligand to the corresponding imine-type PDI·−π-radical anion and diimine-type PDI^(2−)dianion,which positions them as candidates for prototypes of spin quantum transistors and capacitors,offering potential applications in quantum information processing.
基金supported by several sources:the CNRS,the University of Bordeaux,the“Agence Nationale de la Recherche”(ANR project BISTA-MAT:ANR-12-BS07-0030-01 ANR project FEMTOMAT:ANR-13-BS04-0002)the“Region Nouvelle Aquitaine”,a JSPS Grant-in-Aid for Specially Promoted Research(Grant Number JP15H05697)+5 种基金a Grant-inAid for Scientific Research on Innovative Area Soft Crystals(Area No.2903,JP17H06367)a Grant-in-Aid for Scientific Research(A)(Grant Number JP20H00369)IM-LED LIA(CNRS)and the Algerian General Directorate of Scientific Research and Technological Development(DGRSDT)We acknowledge the Cryogenic Research Center,The University of Tokyo,the Center for Nano Lithography&Analysis,The University of Tokyo supported by MEXT,and the MEXT Quantum Leap Flagship Program(MEXT Q-LEAP)(JPMXS0118068681)K.K.is grateful to a Grant in-Aid for JSPS fellows(Grant Number JP20J20245)O.S.is thankful for JSPS KAKENHI Grant Number JP21K14582。
文摘Thermal desolvation is a very attractive method for the post-synthetic modification of the physicochemical properties of switchable materials.In this field of research,special attention has been paid to the possibility of modifying the thermo-and photo-induced spin crossover(SCO)properties of metal complexes as they can act as solvent sensors.Two new[Fe(3-bpp)_(2)](ClO_(4))_(2)·2.5H_(2)O·MeOH(1·sol)and[Fe(3-bpp)_(2)](ReO_(4))_(2)·3H_(2)O(_(2)·sol)compounds.
文摘The literature tetradentate acyclic Schiff base ligand HL^(H-OH)(from the 2:1 reaction of pyridine-2-carboxylaldehyde with 1,3-diamino-2-propanol)was alkylated using a range of 1-bromoalkanes varying in length,BrR(R=C_(10)H_(21),C_(16)H_(33),C_(18)H_(37),C_(20)H_(41)and C_(22)H_(45))to yield five new ligands,LH-OR.The synthesis,magnetic and Langmuir characteristics of the corresponding family of six neutral mononuclear Fe(II)complexes,the parent complex[FeII(HLH-OH)(NCBH_(3))_(2)]and the five alkylated ligand derivatives[Fe^(II)(L_(H-OR))(NCBH_(3))_(2)],is detailed.The solution spin crossover temperature,T_(12),can be tuned by two methods:(a)increasing the solvent polarity index(P’)from 5 to 7 increases T_(12)by 172 K,whereas(b)increasing the tail length from C_(10)to C_(22)decreases T_(12)by 115 K.In both cases strong linear correlations are observed,so both of these,choice of solvent(R^(2)=0.99,albeit only for three solvents)and of tail length(R^(2)=0.98,for five complexes),are levers for the predictable tuning of the spin state in advance of synthesis.The compounds with longer tails,C_(18),C_(20)and C_(22),showed a small window of thermal hysteresis(<5 K)in D_(3)-acetonitrile solution.Water solubility hampered the formation of Langmuir films of these complexes.But the use of a 1:1 mixture of stearic acid with[Fe^(II)(LH-OC_(18))(NCBH_(3))_(2)]facilitated the formation of a stable Langmuir film,a monolayer of which was transferred onto a quartz slide:multi-layering was not possible.
基金supported by the National Natural Science Foundation of China(21401104)X.B.is thankful for the financial support from the State Key Laboratory of Coordination Chemistry of Nanjing University.J.T.acknowl-edges the support from the Ministry of Education,Youth and Sports of the Czech Republic under Project No.LO1305.
文摘A precise regulation of the temperature of spin crossover(SCO)is an essential task to envisage practical applications of switchable materials.Here,we present three isostructural complexes with the formula[Fe(LCl)(NCE)_(2)],where LCl is the tetradentate ligand N,N′-bis[(4-chloro-2-pyridyl)methyl]ethane-1,2-diamine and E=S(1-S),Se(1-Se),and BH_(3)(1-BH_(3)).
基金supported by the National Key Research and Development Program of China(2018YFA0306001)the NSFC(22075323)the Pearl River Talent Plan of Guangdong(2017BT01C161).
文摘The pursuit of spin crossover(SCO)materials with photoswitchable multistability is driven by fascinating perspectives toward light-response switches and opto-magnetic memory devices.Herein,we report a 3D Hofmann-type metal–organic framework[Fe(bpn){Ag(CN)_(2)}_(2)]·1.5(Fnaph)(bpn=1,4-di(pyridin-4-yl)naphthalene,Fnaph=1-fluoronaphthalene),which displays an incomplete two-step SCO behaviour.The asymmetric host–vip interactions induce an intermediate HS–LS state at low temperature.Photomagnetic measurements exhibited an extremely rare bidirectional light-induced excited spin-state trapping(LIESST)effect with green and near-IR light irradiation,in which both metastable HS*and hidden LS*states were revealed at 10 K.The light-induced tristability paves the way for designing optomagnetic memory devices.
基金supported by the National Key Research and Development Program of China(2018YFA0306001)the NSFC(21771200,21773316 and 21821003)the Pearl River Talent Plan of Guangdong(2017BT01C161).
文摘Spin crossover(SCO)compounds are bistable in nature but can exhibit five main types of SCO behaviors as collective phenomena.Here,incomplete,gradual,step,abrupt and hysteretic types of SCO behaviors can be observed in the magnetic curve of a 3D Hofmann-type metal–organic framework[Fe(dpt){Pt(CN)_(4)}]·dpt·2.5H_(2)O(1·dpt·2.5H_(2)O,dpt=2,5-di(pyridine-4-yl)thiophene).It hints that the variable-temperature spin transition process can be more complicated than thus far anticipated.Meanwhile,two-and three-step SCO behaviors are displayed for the partially and fully dehydrated phases 1·dpt·1.5H_(2)O and 1·dpt,respectively.Reversible SCO modulations are further proved by water adsorption.The magnetostructural corrections suggest that SCO behaviors can even be tuned by the weak host–vip hydrogenbonding interactions,which provides great opportunities to design chemosensors.
基金Centro de Química Estrutural(CQE)and Institute of Molecular Sciences(IMS)acknowledge the financial support of Fundação para a Ciência e Tecnologia(FCT),projects UID/00100/2025,UID/PRR/100/2025LA/P/0056/2020(https://doi.org/10.54499/LA/P/0056/2020),respectively+6 种基金Centro de Física Teórica e Computacional(CFTC)acknowledges FCT under contracts no.UIDB/00618/2020(https://doi.org/10.54499/UIDB/00618/2020)and UIDP/00618/2020(https://doi.org/10.54499/UIDP/00618/2020).PN Martinho thanks FCT for grant PTDCQUI-QIN0252_2021(https://doi.org/10.54499/PTDC/QUI-QIN/0252/2021)for contract 2023.15441.TENURE.003/CP00003/CT00011 and the co-financing by the PRR-Recovery and Resilience Plan of the European UnionThis research was partly funded by ANR(Agence Nationale de la Recherche Scientifique),grant number Mol-CoSM ANR-20-CE07-0028-0CNRS through the MITI interdisciplinary programs through its exploratory research program.The authors acknowledge financial support from the Spanish Ministerio de Ciencia e Innovación through grants MCIN/AEI/10.13039/501100011033 PID2021-126076NB-I00 and TED2021-129506B-C22,funded partially by FEDER Una manera de hacer Europa,the unit of excellence María de Maeztu CEX2021-001202-M granted to the IQTCUB,the COST Action CA18234the Generalitat de Catalunya 2021SGR00079 grantF.V.thanks the ICREA Academia Award 2023 Ref.Ac2216561COST Actions CA21101(COSY)and CA22131(LUCES)are also acknowledged.
文摘We report the unprecedented observation of reversible interface propagation in the switchable cooperative Fe(Ⅲ)spin crossover compound[Fe(3-EtO-salEen)_(2)]NO_(3),where 3-EtO-salEen is 3-ethoxy-N-ethyl-N-(2-aminoethyl)salicylaldiminate.This complex exhibits a spin transition from low-spin to high-spin states,triggered by temperature around 345 K.Magnetic susceptibility measurements reveal an abrupt transition with a thermal hysteresis of 5 K.Differential scanning calorimetry confirms both endothermic(T_(on)=344.50 K and T_(max)=345.61 K,Δ_(trs)H°_(m)=12:05 kJ mol^(-1)andΔ_(trs)S°_(m)=34:98 J mol^(-1))and exothermic(T_(on)=344.40 K,T_(max)=345.49 K,Δ_(trs)H°_(m)=10:98 kJ mol^(-1)andΔ_(trs)S°_(m)=31:88 J mol^(-1))peaks corresponding to the spin transition temperatures.Cryogenic optical microscopy reveals rapid interface propagation,with velocities(v_(HS→LS)≃1672μm s^(−1)and v_(LS→HS)≃850μm s^(−1))significantly higher than those observed in traditional Fe(II)-based spin crossover materials.The high-speed propagation is attributed to the combined effect of the reduced volume change and lower elastic energy barriers associated with the transition in Fe(Ⅲ)systems and the high values of the transition temperatures.Hirshfeld surface analysis reveals that the cooperative nature of the transition is influenced by non-conventional hydrogen bonding andπ-πinteractions.This study represents the first report of reversible interface propagation in Fe(Ⅲ)complexes,providing valuable insights into the fundamental mechanisms that govern spin crossover transitions in these systems.
文摘Four new bidentate 5-(Z-pyridine)-4-(4-methyl-phenyl)-3-phenyl-1,2,4-triazole ligands L^(pytZ)(meta-Z=CF_(3),Br,F,Me)and the corresponding family of[Fe^(II)(L^(pytZ))_(2)(NCBH_(3))_(2)]complexes,in addition to the literature unsubstituted analogue[Fe^(II)(L^(pytH))_(2)(NCBH_(3))_(2)],are prepared and studied herein.Single crystal structure determinations on all four new complexes confirmed the expected octahedral coordination,with trans-NCBH_(3)co-ligands.Solid-state variable temperature magnetic studies of air-dried crystals showed that[Fe^(II)(LpytCF_(3))_(2)(NCBH_(3))_(2)]is SCO active with a hysteresis loop at 208 K(T_(1/2)↓=203 K,T_(1/2)↑=213 K;ΔT_(1/2)=10 K);[Fe^(II)(LpytBr)_(2)(NCBH_(3))_(2)]is not SCO active until heated above RT,while[Fe^(II)(L^(pytF))_(2)(NCBH_(3))_(2)]and[Fe^(II)(L^(pytMe))2(NCBH_(3))_(2)]are SCO active close to RT(T_(1/2)=290 and 300 K respectively).Solution phase variable temperature Evans NMR method studies in CDCl_(3)showed that four of the complexes were SCO active close to RT(T_(1/2)=279-294 K)whilst[Fe^(II)(LpytCF_(3))_(2)(NCBH_(3))_(2)]was mostly LS at RT(T_(1/2)∼374 K).These solution phase T_(1/2)values,and those for four literature families of bi-(five Lazine),tri-(fourteen bppX,Y,twelve pyboxX)or tetra-dentate(seven pytacnX)ligands,which feature para(X)pyridine or meta(Y)pyrazole ring substituents,are used,along with the calculated^(15)N NMR chemical shift of the coordinating azine/azole nitrogen(N_(A))in the ligand(for all forty-two ligands;using a refined protocol),to test the generality of the previously reported correlation ofδN_(A)chemical shift in the free ligand with the solution T_(1/2)for the respective iron(II)complex.Moderately good to excellent correlations ofδN_(A)with T_(1/2)were observed for each of the ligand families with a para substituent(R^(2)=0.69-0.96),whereas there is no correlation when meta substituents are modified(R^(2)=0.15-0.37),probably because the electronic impact of this is too small.Finally,δNA also shows promise as an easily calculated measure of the electronic effect of any substituent,in contrast to the Hammett constant(σp^(+))which is not available for all possible substituents.
基金supported by the Australian Research Council through grant number DP200100305.
文摘Spin crossover frameworks and molecular crystals display fascinating collective behaviours.This includes multi-step transitions with hysteresis and a wide variety of long-range ordered patterns of high-spin and low-spin metal centres.From both practical and fundamental perspectives it is important to understand the mechanisms behind these collective behaviours.We study a simple model of elastic interactions and identify thirty six different spin-state ordered phases.We observe spin-state transitions with between one and eight steps.These include both sharp transitions and crossovers,and both complete and incomplete spin crossover.We demonstrate structure–property relationships that explain these differences.These arise because through-bond interactions are antiferroelastic(favour metal centres with different spinstates);whereas,through-space interactions are typically ferroelastic(favour the same spin-state).In general,rigid materials with longer range elastic interactions lead to transitions with more steps and more diverse spin-state ordering,which explains why both are prominent in frameworks.
基金National Natural Science Foundation of China(Grants 21525103,21871247 and 21801237)the Key Research Program of Frontier Sciences,CAS(Grant ZDBS-LY-SLH023),for financial supportthe support from the Royal Society-Newton Advanced Fellowship(NA160075).
文摘The assembly of molecules simultaneously exhibiting slow magnetic relaxation and spin crossover(SCO)behaviors at the molecular level is a fascinating challenge for chemists.The synthesis strategy of combining 3d and 4f ions in a molecule is a very promising route to a dual magnetic system.With this goal in mind,a series of mixed-metal structures,namely[Dy_(2)Fe_(2)(H_(2)L)_(4)(OH)_(6)](NO_(3))_(4)·12CH_(3)OH·6H_(2)O(1),[Dy_(2)Fe_(2)(H_(2)L)_(4)(OH)_(6)]Cl_(4)·2CH_(3)OH·20H_(2)O(2),[Dy_(2)Fe_(2)(H_(2)L)_(4)(OH)_(6)]Cl_(4)·4CH_(3)OH·20H_(2)O(3)and[Dy_(2)Fe_(2)(H_(2)L)_(4)(NO_(3))_(3)CH_(3)O](NO_(3))_(5)(CF_(3)SO_(3))·6CH_(3)OH·H_(2)O(4)containing a versatile Schiff-base ligand N’-((E)-pyridin-2-ylmethylene)-6-(2-((E)-pyridin-2-ylmethylene)hydrazinyl)nicotinohydrazide(H_(2)L),have been synthesized and characterized.Alternating current(ac)susceptibility measurements reveal that complexes 1-4 exhibit a slow magnetic relaxation behavior.More importantly,complexes 2 and 3 exhibit one-and two-step SCO behaviors,respectively.To our knowledge,this is the first report on 3d-4f structures that exhibit the dual function of slow magnetic relaxation and SCO behaviors to date.
文摘In the perspective of elaborating functional devices based on inorganic molecular materials,it is important not only to continue research on their synthesis and to understand their properties but also to develop new strategies for their processing and shaping.In this context,we show here that centimeter-scale materials exhibiting solid state-like spin-crossover(SCO)properties and easy handling under ambient conditions can be obtained that preserve their thermochromic properties over months.Combining a triazole-based Fe(II)SCO compound with functionalized silica nanoparticles gives rise to nanocomposite soft gels.These gels were used as templates for the formation of a flexible macroporous hybrid silica network via a vapor phase sol–gel process.Further coating with PDMS provided both long-term protection of the material against drying and operationality in aqueous media.Our approach offers new hopes for the development of optical and magnetic devices based on SCO coordination polymers.
基金the Generalitat de Catalunya for the prize ICREA Academia 2008 and 2013,and acknowledge the ERC for the Starting Grant StG-2010-258060(GA)MINECO for grants MAT2014-53961-R(OR),MAT2015-70868-ERC(OR),CTQ2012-32247(GA)and CTQ2015-68370-P(GA,CBM,RD)+2 种基金LabEx-Chemistry of Complex Systems for the post-doctoral grant ANR-10LABX-0026CSC(SV)the regional High-Performance Computing(HPC)center in Strasbourg for computational resources(SV)and the Avempace II Erasmus Mundus Action 2program for a PhD scholarship(MD).the Advanced Light Source,which is a DOE Office of Science User Facility under contract no.DE-AC02-05CH11231.
文摘Identifying and quantifying the individual factors affecting the temperature and properties of the spin crossover in transition metal complexes is a challenging task,because many variables are involved.While the most decisive factor is the crystal field imparted by ligands around the active metal center,some less common actors are intramolecular steric repulsions or non-covalent interactions.
基金supported by the NSFC(Grant No.22488101)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23ptpy73)Science and Technology Program of Guangzhou,China(2024A04J4433).
文摘Spin crossover(SCO)compounds are versatile platforms for incorporating functional ligands,enabling profuse magnetic regulating strategies and providing new likelihood for diversified practical applications of magneto-switches and information storage devices.Among the copious choices for stimuli-responsive ligands,diarylethene stands out as a photochromic unit that can be integrated into magnetic materials.Here,we report a triple interpenetrating SCO framework[Fe^(II)(Lo)_(2){Ag(CN)_(2)}_(2){Ag(CN)}_(2)](1,Lo=1,2-bis(2-methyl-5-(pyridin-4-yl)thiophen-3-yl)cyclopent-1-ene)with heterometallic nodes.Distinct from the conventional SCO frameworks in which Fe^(II) centers are directly bridged by organic ligands,the coordination fashion in 1 is manifested as Fe^(II)-Lo-Ag^(I)-Lo-Fe^(II).Photochromism is partially realized by the alternation of 365 nm and 520 nm light irradiation due to the tightly packed lattice.Subtle magnetic switching is observed from 1 to 1^(UV).Moreover,1^(UV) displays a photothermal response up to 162℃ under 808 nm light irradiation,with an enhancement in the photothermal conversion efficiency compared with that of 1.This thermally stable three-dimensional framework provides new structural possibilities for SCO polymers and takes a step forward in the assembly of UV-Vis-NIR responsive magnetic materials.
基金supported by the National Natural Science Foundation of China(22273036 and 21973039)。
文摘Using a self-assembly process involving a[Mo^(Ⅲ)(CN)_(7)]^(4−)unit,an Fe^(Ⅱ) ion,and a 1,4-bis(4H-1,2,4-triazol-4-yl)benzene(btb)ligand,we have synthesized a novel coordination polymer,denoted as{K_(2)Fe^(Ⅱ)(btb)[Mo^(Ⅲ)(CN)_(7)]·5H_(2)O}n(1).Single-crystal structure analysis revealed a three-dimensional(3D)Hofmann-type framework for compound 1.The[Mo^(Ⅲ)(CN)_(7)]^(4−)unit engaged four cyanide groups to coordinate with Fe^(Ⅱ) ions,creating an anionic two-dimensional(2D)cyano-bridged layer of{Fe^(Ⅱ)[Mo^(Ⅲ)(CN)_(7)]}_(n).The btb ligands,in turn,coordinated axially with the Fe^(Ⅱ) ions,bridging adjacent 2D layers and thus constructing a 3D framework.Magnetic studies have shown that compound 1 exhibits a hysteretic one-step spin-crossover behavior.Moreover,a ferrimagnetic ordering with a critical temperature of approximately 65 K was also observed,which may be ascribed to the compound’s“core-shell”architecture:the main core is responsible for the SCO behavior,while the shell contributes to the ferrimagnetic characteristics.To the best of our knowledge,this is the first observation of spin-crossover behavior in compounds based on the[Mo^(Ⅲ)(CN)_(7)]^(4−)unit.
基金supported by the National Natural Science Foundation of China(No.21271052 and 21905062)the Science and Technology Program Foundation of Guangdong Province(No.2015A030313502).
文摘An azo-based ligand of azotetrazolyl-2,7-dihydroxynaphthalene(H3ATD)was used to synthesize three unprecedented Fe^(Ⅲ)-M^(Ⅱ)-Fe^(Ⅲ)(M=Fe,Cd)linear trinuclear complexes with different high temperature spin crossover(SCO)behaviours for the terminal Fe^(Ⅲ)ions.
文摘The authors regret that there were some errors in the original article.In the first paragraph of the Synthesis section in the Experimental section,in the sentence beginning“A 5 mL vial containing…”,the quantity of L_(o) was incorrectly given as“0.05 mmol,10.3 mg”.This should be“0.05 mmol,20.7 mg”.
