Novel hydrogen-bonded three-dimensional supramolecular architectures containing 2D honeycomb networks or 2D grids

Two new supramolecular complexes, [Cu(H(2)dhbd)(3-pyOH)(H2O)](2)center dot 3-pyOH center dot 2H(2)O (1) and [Cu-2(dhbd)(dpa)(2)-(H2O)]center dot 6H(2)O (2) (H(4)dhbd=2,3-dihydroxybutanedioic acid, 3-pyOH=3-hydroxypyridine, dpa=2,2'-dipyridylamine), have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analyses, UV-Vis and IR spectra, and TGA analysis. X-ray structural analysis revealed that, through four pairs of strong O center dot center dot center dot H-O hydrogen bonds, the cyclic dinuclear units in 1 together with four adjacent neighbors are connected into a 2D honeycomb network encapsulating free 3-pyOH ligands. Unexpectedly, the water-dimers are fixed in interlayers of 2D honeycomb network and act as hydrogen-bond bridging to further extend these 2D networks into 3D hydrogen-bonded framework. Complex 2 includes interesting 2D grids constructed from chiral dinuclear units through strong O center dot center dot center dot H-O and O center dot center dot center dot H-N hydrogen bonding, which are extended through other crystallization water molecules into three dimension with channels. Variable-temperature magnetic susceptibility measurements for both complexes indicate the presence of weak antiferromagnetic exchange interactions between adjacent copper(II) ions.