Reversible color changes of metal(II)-N-1,N-3-di(pyridin-4-yl)isophthalamide complexes via desolvation and solvation

Four metal(II)-N-1,N-3-di(pyridin-4-yl)isophthalamide (L) complexes formulated as [Cu(L)(2)Cl-2]center dot 5.5H(2)O (1), [Ni(L)(2)Cl-2]center dot 5.5H(2)O (2), [Co(L)(m-BDC)]center dot DMF (3) (m-BDC = 1, 3-benzenedicarboxylic dianion) and [Cd-2(L)(2)(m-BDC)(2)]center dot DMF center dot 0.2H(2)O (4) have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffractions. Complexes 1 and 2 are isomorphous, both of them exhibit chain-like frameworks, in which ligand L shows a cis-conformation. Complex 3 displays a three dimensional architecture constructed by ligand L with intermediate-conformation linking different chains. Complex 4 shows a corrugated two dimensional layer in which ligand L with trans-conformation and m-BDC act as bridging groups linking different Cd(II) centers. The four complexes all possess stable host frameworks, and complexes 1-3 show reversible color changes via desolvation and solvation.