The hydrothermal reaction of the pyridine-2,4-dicarboxylate (2,4-pdc) dianion with various 3d metal(II) cations resulted in the formation of a series of one-, two- and three-dimensional coordination polymers with varied network topologies. 2,4-pdc reacted directly with MnCl2
or FeCl2 in water at 200 °C under mild basic conditions to give a dense three-dimensional polymer, [M(2,4-pdc)] (M = Mn, 1a; M = Fe, 1b), which supports a highly-connected three-dimensional magnetic exchange lattice. Both 1a and 1b undergo antiferromagnetic
ordering and the latter Fe(II)-containing material exhibited spin-canting behavior below 6.5 K. Reaction of 2,4-pdc with CoCl2 under identical conditions gave an unusual zigzag chain polymer, [Co4(2,4-pdc)4(OH2)10](2), that has
large amounts of coordinated H2O. The magnetism of 2 based on isolated Co(II) dimers was modeled using a modified van Vleck approach. Adjustment of the reaction pH resulted in the formation of additional Co(II)-containing materials with strongly contrasting structures: at
lower pH in the presence of oxalic acid, the same reaction components gave a protonated molecular species, [Co(2,4-pdcH)2(OH2)2]·2H2O (3); at higher pH in the presence of excess hydroxide, a highly porous, three-dimensional material
was obtained, [Co3(μ3-OH)2(2,4-pdc)2]·9H2O (4a). 4a contains cobalt hydroxide chains, whose magnetic behavior has been studied in detail by neutron diffraction. A Ni(II)-containing analogue was also prepared
using NiCl2 (4b), which shows weak antiferromagnetic coupling. Attempts to obtain a Zn(II)-based analogue of the porous material 4 gave instead a unique coordination material, [Zn(μ2-OH)2(2,4-pdc)] (5), which contains uncommon
zinc hydroxide bridging modes.
Journal for Nanoscience and Nanotechnology (JNN) is an international and multidisciplinary peer-reviewed journal with a wide-ranging coverage, consolidating research activities in all areas of nanoscience and nanotechnology into a single and unique reference source. JNN is the first cross-disciplinary journal to publish original full research articles, rapid communications of important new scientific and technological findings, timely state-of-the-art reviews with author's photo and short biography, and current research news encompassing the fundamental and applied research in all disciplines of science, engineering and medicine.