Boosting the proton conduction in a magnetic dysprosium-organic framework by introducing conjugate NH_(4)^(+)-NH_(3)pairs

Metal-organic frameworks(MOFs)with inherent porosity and suspended acidic groups are promising proton conducting materials in water or aqua-ammonia media.Herein we report a new lanthanide phosphonate,namely,Dy_(2)(amp_(2)H_(2))_(2)(mal)(H_(2)O)_(2)·5H2O(MDAF-6).It possesses a 3D open-framework structure,and shows a high NH_(3)adsorption capacity of 142.4 cm^(3)/g at P/P0=0.98 at 298 K due to acid-base interaction.Interestingly,the proton conductivity of MDAF-6-NH3 is enhanced by five orders of magnitude compared to MDAF-6 after 8.5 h exposure in saturated NH_(3)-H_(2)O vapor,indicating the importance of coexistent conjugate acid-base pairs of H_(3)O+-H_(2)O and NH_(4)^(+)-NH_(3)in promoting proton conduction.Magnetic studies of MDAF-6 revealed slow magnetization relaxation under zero dc field,characteristic of singlemolecule magnet behavior.This work provides not only a new multifunctional MOF material,but also a new strategy to improve proton conduction in aqua-ammonia medium.

M_2(pbtcH)(phen)_2(H_2O)_2[M(Ⅱ)=Co,Ni]:Mixed-ligated metal phosphonates based on 5-phosphonatophenyl-1,2,4-tricarboxylic acid showing double chain structures

Two new mixed-ligated metal phosphonates, M2（pbtcH）（phen）2（H2O）2 [M（Ⅱ）=Co （1）, Ni （2）] （pbtcH5 = 5-phosphonatophenyl-1,2,4-tricarboxylic acid, phen = 1,10-phenanthroline）, have been syn- thesized and characterized. Both show one-dimensional double chain structures, where the M（phen）（H2O） moieties are chelated and bridged by pbtcH4 through the carboxylate and phosphonate oxygen atoms. The chains are connected by hydrogen bonding interactions and π-π stacking, forming a three-dimensional supramolecular structure. The IR and magnetic properties of the two compounds are also investigated.

Engineering Heteronuclear Arrays from Ir^(Ⅲ)-Metalloligand and Co^(Ⅱ)Showing Coexistence of Slow Magnetization Relaxation and Photoluminescence

Three heteronuclear Ir^(Ⅲ)-Co^(Ⅱ)arrays,[Co(H_(2)O)6]_(2)[Ir(ppyCOO)(ppyCOOH)(bpy)]_(2)[Ir(ppyCOO)_(2)(bpy)]_(2)(NO_(3))2·10.5H_(2)O(2),[Co(H_(2)O)6]{Co-(H_(2)O)4[Ir(ppyCOO)_(2)(bpy)]_(2)}[Ir(ppyCOO)_(2)(bpy)]2·15H_(2)O(3)and{Co(H_(2)O)2[Ir(ppyCOO)_(2)(bpy)]_(2)}·2CH_(3)OH·3H_(2)O(4),have been synthe-sized by combining paramagnetic Co^(Ⅱ)ion with luminescent Ir^(Ⅲ)-metalloligand,[Ir(ppyCOOH)_(2)(bpy)][Ir(ppyCOO)_(2)(bpy)]·5H_(2)O(1),where ppyCOOH=3-(pyridin-2-yl)benzoic acid and bpy=2,2'-bipyridyl.Owing to the variable charged states of compound 1 at dif-ferent pH,compounds 2 and 3 are discrete ionic complexes containing hydrated Co^(2+)cations and deprotonated[Ir(ppyCOO)_(2)(bpy)]-anions as well as coexisting neutral[Ir(ppyCOO)(ppyCOOH)(bpy)](for 2)or Co(H_(2)O)_(4)[Ir(ppyCOO)_(2)(bpy)]_(2) trinuclear molecule(for 3).Whereas compound 4 consists of self-assembled two-dimensional coordination polymer with Co-metalloligand dative bonds.The hexa-coordinated Co^(Ⅱ)cores in all complexes display octahedral geometries with varying degrees of distortion.In a bias dc field,the ac susceptibilities for 2-4 reveal slow magnetic relaxation.Moreover,the solid-state phosphorescence is observed for compounds 2 and 3 due to weak supramolecular interaction between Co^(Ⅱ)ion and Ir-moiety but is severely quenched for 4,where the Co center is strongly connected to the metalloligand.To the best of our knowledge,this is the first report of Ir-Co systems showing both slow magnetization relaxation and photoluminescence.

Thermo-induced structural transformation with synergistic optical and magnetic changes in ytterbium and erbium complexes

Dinuclear ytterbium and erbium based bifunction complexes Ln_(2) L_(2)(depma_(2))Cl_(2)(1-Ln,Ln=Yb and Er,H_(2) L=N~1,N~3-bis(salicylideneimino)diethylenetriamine,depma_(2)=dimerized 9-diethyl-phosphonomethylanthracene)are reported.They undergo thermo-induced consecutive phase transitions,first the dissociation of depma_(2) ligand forming LnL(depma)Cl(2-Ln)and then the release of chloroethane forming LnL(epma)(3-Ln,epma=9-ethylphosphonomethylanthrancene).The structural transformations are accompanied with synergetic switch of the luminescence in visible and NIR regions and also magnetic dynamics.