Reactions of DyCl_(3)·6H_(2)O or Dy_(2)O_(3) with 2-quinolinecarboxylic acid(H-QLC)yielded two compounds,namely,[Dy_(4)(QLC)_(12)(H_(2)O)_(6)]·4H_(2)O(1)and[Dy(QLC)_(3)(H_(2)O)_(2)]_(n)(2).Compound 1 is a li...Reactions of DyCl_(3)·6H_(2)O or Dy_(2)O_(3) with 2-quinolinecarboxylic acid(H-QLC)yielded two compounds,namely,[Dy_(4)(QLC)_(12)(H_(2)O)_(6)]·4H_(2)O(1)and[Dy(QLC)_(3)(H_(2)O)_(2)]_(n)(2).Compound 1 is a linear tetranuclear structure with one central[Dy_(2)(QLC)_(4)(H_(2)O)_(4)]subunit and two terminal[Dy(QLC)_(3)(H_(2)O)]subunits linked by bridging QLC^(-)ligands.Compound 2 has a one-dimensional(1D)chain wherein the[Dy(QLC)_(2)]unit formed by two QLC^(-)ligands chelating a Dy(Ⅲ)ion is connected by the bridging QLC^(-)ligands.Compounds 1 and 2 exhibit slow magnetic relaxation behaviour in the absence of a static magnetic field,which is rarely observed in lanthanide-carboxylate compounds.During the structural evolution from a linear Dy_(4) cluster of 1 into a 1D chain of 2,the anisotropy energy barrier(U_(eff))is enhanced from 45.4(2)to 144.2(1)K.Though the Dy(Ⅲ)centers in 1 and 2 all are eight-coordinated with square antiprismatic coordination environments,the higher energy barrier observed for 2 could be the result of a more favorable crystal field for the Dy(Ⅲ)ions in 2.展开更多
基金supported by the NNSF of China(Grants,21561015,21361011,and 21661014)the Young Scientist Training Project of Jiangxi Province(Grant 20153BCB23017)the NSF of Jiangxi(Grant 20151BAB203002).
文摘Reactions of DyCl_(3)·6H_(2)O or Dy_(2)O_(3) with 2-quinolinecarboxylic acid(H-QLC)yielded two compounds,namely,[Dy_(4)(QLC)_(12)(H_(2)O)_(6)]·4H_(2)O(1)and[Dy(QLC)_(3)(H_(2)O)_(2)]_(n)(2).Compound 1 is a linear tetranuclear structure with one central[Dy_(2)(QLC)_(4)(H_(2)O)_(4)]subunit and two terminal[Dy(QLC)_(3)(H_(2)O)]subunits linked by bridging QLC^(-)ligands.Compound 2 has a one-dimensional(1D)chain wherein the[Dy(QLC)_(2)]unit formed by two QLC^(-)ligands chelating a Dy(Ⅲ)ion is connected by the bridging QLC^(-)ligands.Compounds 1 and 2 exhibit slow magnetic relaxation behaviour in the absence of a static magnetic field,which is rarely observed in lanthanide-carboxylate compounds.During the structural evolution from a linear Dy_(4) cluster of 1 into a 1D chain of 2,the anisotropy energy barrier(U_(eff))is enhanced from 45.4(2)to 144.2(1)K.Though the Dy(Ⅲ)centers in 1 and 2 all are eight-coordinated with square antiprismatic coordination environments,the higher energy barrier observed for 2 could be the result of a more favorable crystal field for the Dy(Ⅲ)ions in 2.
