New Two-Dimensional Metal−Organic Networks Constructed from 1,2,4,5-Benzenetetracarboxylate and Chelate Ligands

Two novel nickel coordination polymers [Ni2(2,2‘-bipy)2(OH)2(H2btec)]3n (1) and [Ni2(1,10‘-phen)2(H2O)2(btec)]n (2)
(btec = 1,2,4,5-benzenetetracarboxylate) have been hydrothermally synthesized and characterized by elemental
analyses, IR and XPS spectra, TG analysis, X-ray powder diffraction, and single crystal X-ray diffraction. Crystal
data for 1:  C90H66N12O30Ni6, monoclinic P21/c, a = 10.905(2) Å, b = 18.006(4) Å, c = 20.551(4) Å, β =
94.91(3)°, Z = 2. Crystal data for 2:  C34H22N4O10Ni2, monoclinic P21/n, a = 10.122(2) Å, b = 9.3106(19) Å, c =
15.690(3) Å, β = 92.03(3)°, Z = 2. Compound 1 exhibits a novel one-dimensional chainlike structure, in which the
dinuclear Ni centers are linked by the btec ligands. Furthermore, the adjacent chains are linked into a 2-D wavelike
layer via the strong OH···O hydrogen bonding interactions. Compound 2 possesses an unusual two-dimensional
steplike network with interesting rhombic grids. Both compounds exhibit unprecedented metal−organic ligand
construction modes in {M/btec/L} (M = transition metal; L = chelate ligands) systems. The magnetic behaviors
of compounds 1 and 2 have been studied.