Two multifunctional Dy(iii)-based metal-organic frameworks exhibiting proton conduction, magnetic properties and second-harmonic generation

The construction of multifunctional metal-organic frameworks (MOFs) has attracted considerable attention. Two novel Dy-MOFs namely [Dy-2(TPTC-2OMe)(1.5)(H2O)(4)H2O](n) (1) and {[Dy-2(TPTC-2OMe)(H2TPTC-2OMe)(H2O)(2)]2H(2)O}(n) (2) were obtained by a solvothermal method using 2 ',5 '-dimethoxy-[1,1 ':4 ',1 ''-terphenyl]-4,4 ''-dicarboxylic acid (H4TPTC-2OMe) as the ligand. Structure analysis demonstrates that both MOFs 1 and 2 displayed three-dimensional framework structures, in which MOF 1 was with Dy(III) metal chains as nodes, while MOF 2 was with Dy-2 binuclear metal clusters as nodes. Interestingly, MOFs 1 and 2 exhibited high thermal and chemistry stabilities and presented relatively high proton conductivity (sigma) values of 1.69 x 10(-4) S cm(-1) and 3.52 x 10(-6) S cm(-1) at 50 degrees C and 98% RH. Although there exist a large number of coordinated or free H2O molecules in both structures, it is easier to form an ordered hydrogen-bonding network between the coordinated H2O molecules in the structure of MOFs, resulting in a more excellent proton conductivity of MOF 1. Moreover, MOF 1 exhibited field-induced single-molecule magnet (SMM) behavior with energy barriers (U-eff) of 37.22 K (tau(0) = 9.27 x 10(-8) s). Furthermore, MOF 1 exhibits obvious second-order nonlinear optical properties. This research provides guidance for the design of novelty multifunctional MOF materials.