Synthesis and structures of CoII, NiII, and CuII coordination frameworks formed by a flexible 1,3-phenylenediacetic acid ligand

Three new compounds of CoII, NiII and CuII with a flexible dicarboxylate building block 1,3-phenylenediacetate, along with 4,4′-bipyridine, or 4,4′-trimethylenedipyridine co-ligands, with the formula {[Co2(4,4′-bipy)2(1,3-pda)2]·1.5H2O} n (1), {Ni(4,4′-bipy)(1,3-pdaH)2(CH3CH2OH)2} n (2), and {Cu(tmdp)(1,3-pda)} n (3), (where, 1,3-pda=1,3-phenylenediacetate, 4,4′-bipy=4,4′-bipyridine, and tmdp=4,4′-trimethylenedipyridine) have been synthesized and structurally characterized. Compound 1 was synthesized hydrothermally at 180°C, whereas 2 and 3 were synthesized at room temperature in H2O/ethanol medium. The 2D coordination network of 1 is formed by pillaring the 1D staircase Co2(1,3-pda)2 chain by 4,4′-bipy, whereas the 3D supramolecular framework 2 is constituted by connecting the 2D H-bonded Ni(1,3-pdaH)2(C2H5OH)2 sheets. Compound 3 shows an unusual 2D network which is built by the flexible 1,3-pda and tmdp linkers by connecting Cu2(1,3-pda)2 dimeric building unit.