摘要
Three new MOFs with the same components but different structures and magnetic behavior, {[Cu6（atr）6（H20）2（,u3- OH）2（SOa）5]＇5.25H20}n （1）, {[Cu2（atr）2（,t/-OH）2（SOa）].3H20}n （2）, and {[CuT（atr）6（H20）6（fl3-OH）2（SOn）6].2H20}n （3） （atr= 4-amino-l,2,4-triazole）, were respectively synthesized by diffusion reactions in the presence of different structure-directing agents. Complex 1 is a slightly spin-frustrated antiferromagnetic layer with sulfonate aggregated Cun6 clusters periodically ex- tended by ditopic sulfonate linkers. 2 is a grid-based coplanar sheet with hydroxyl group bridged -CuOCu- linear-chain inter- linked by pairs of p3-atr ligands, exhibiting strong antiferromagnetic interactions to lead to an S = 0 spin ground state at low temperature. In contrast, air-instable 3 has a ladder-like broad-ribbon structure constructed from triangular CuII3 cores and cen- trosymmetric CuII1 octahedra. Obviously, the variable Cun-ligand connectivity and the involving magnetic properties are sig- nificantly dominated by the cooperative and variable binding modes of the mixed sulfonate-atr ligands and bi-/tridentate bridging hydroxyl heterobridges.
Three new MOFs with the same components but different structures and magnetic behavior, {[Cu6(atr)6(H2O)2(μ3 OH)2(SO4)5 ]·5.25H2O} n (1), {[Cu2(atr)2( -OH)2(SO4 )]·3H2O} n (2), and {[Cu7(atr)6(H2O)6(μ3-OH)2(SO4 )6 ]·2H2O} n (3) (atr = 4-amino-1,2,4-triazole), were respectively synthesized by diffusion reactions in the presence of different structure-directing agents. Complex 1 is a slightly spin-frustrated antiferromagnetic layer with sulfonate aggregated CuⅡ6 clusters periodically extended by ditopic sulfonate linkers. 2 is a grid-based coplanar sheet with hydroxyl group bridgedCuOCulinear-chain interlinked by pairs of μ3 -atr ligands, exhibiting strong antiferromagnetic interactions to lead to an S = 0 spin ground state at low temperature. In contrast, air-instable 3 has a ladder-like broad-ribbon structure constructed from triangular CuⅡ3 cores and centrosymmetric CuⅡ1 octahedra. Obviously, the variable CuⅡ -ligand connectivity and the involving magnetic properties are significantly dominated by the cooperative and variable binding modes of the mixed sulfonate-atr ligands and bi-/tridentate bridging hydroxyl heterobridges.
基金
supported by the National Natural Science Foundation of China (20703030, 20871092)
the Program for New Century Excellent Talents in University (NCET-08-0914)
the Natural Science Foundation of Tianjin (10JCZDJC21600 and 10JCYBJC04800)
