Auxiliary ligand-directed synthesis of four novel functional supramolecular metal–organic frameworks from 1-D chains to 3-D architectures

Four novel functional supramolecular metal–organic coordination polymers, [Cd2Cl3(IP)2(NIPH)2](1), [Zn2(IP)2(μ2-SO4)2(NIPH)2]·2H2O(2), [Cd(IP)2(BPDC)](3), [Zn2(IP)2(NDC)2](4) (IP = 1-H-imidazo[4,5-f][1,10]-phenanthroline, H2NIPH = 5-nitro-isophthalic acid, H2BPDC = 4,4′-biphenyldicarboxylic acid, H2NDC = 2,6-naphthalenedicarboxylic acid), have been obtained through three types of dicarboxylate linkers. All the four compounds are extended into a 3-D supramolecular framework by hydrogen bonds or weak aromatic interactions. The different structures demonstrate the effect of the dicarboxylate ligands on the formation of such coordination architectures. Compound 1 is a 1-D double-stranded loop-like chain with repeated [Cd4(Cl)4]4 + units connected by H2NIPH ligands. In compound 2, there are two indie 1D zigzag chains jointed by sulfate anions with μ2-bridging mode. With different metal centers, compounds 1 and 2 hold different crystal structures. With different auxiliary dicarboxylate ligands, compounds 3 and 4 exhibit disparate 1D chains. The fluorescence property and thermal stability of all complexes are also investigated.

Graphical abstractThe synthetic route of complexes 1–4.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► All compounds exhibit 3D supramolecular net with intermolecular weak interactions. ► With different metal centers, compounds 1 and 2 possess different crystal structures; ► With different auxiliary ligands, compounds 3 and 4 exhibit disparate 1D chains.