Self-Assembled Copper(II) Coordination Polymers Derived from Aminopolyalcohols and Benzenepolycarboxylates: Structural and Magnetic Properties

The new copper(II) or copper(II)/sodium(I) 1D coordination polymers [Cu2(Hmdea)2(μ-H2O)(μ2-tpa)]n·2nH2O (1),
[Cu2(H2tipa)2(μ2-ipa)]n·4nH2O (2), [Cu2(H2tea)2Na(H2O)2(μ2-tma)]n·6nH2O (3), [Cu2(H2tea)2(μ2-ipa)]n·nH2O (4a), and
[Cu2(H2tea)2{μ3-Na(H2O)3}(μ3-ipa)]n(NO3)n·0.5nH2O (4b) have been prepared in aqueous medium by self-assembly
from copper(II) nitrate, aminopolyalcohols [methyldiethanolamine (H2mdea), triisopropanolamine (H3tipa), and
triethanolamine (H3tea)] as main chelating ligands and benzenepolycarboxylic acids [terephthalic (H2tpa), isophthalic
(H2ipa), and trimesic (H3tma) acid] as spacers. They have been characterized by IR spectroscopy, elemental and
single-crystal X-ray diffraction analyses, the latter indicating the formation of unusual multinuclear metal cores
interconnected by various benzenepolycarboxylate spacers, leading to distinct wavelike, zigzag, or linear 1D polymeric
metal−organic chains. These are further extended to 2D or 3D hydrogen-bonded supramolecular networks via
extensive interactions with the intercalated crystallization water molecules. The latter are associated, also with
aqua ligands, by hydrogen bonds resulting in acyclic (H2O)3 clusters in 1, (H2O)8 clusters in 2, infinite 1D water
chains in 3, and disordered water−nitrate associates in 4b, all playing a key role in the structure stabilization and
its extension to further dimensions. Variable-temperature magnetic susceptibility measurements have shown that
1−4 exhibit a moderately strong ferromagnetic coupling through the alkoxo bridge. The small Cu−O−Cu bridging
angle and the large out-of-plane displacement of the carbon atom of the alkoxo group accounts for this behavior.
The magnetic data have been analyzed by means of a dinuclear and a 1D chain model, and the magnetic parameters
have been determined. The magnetic exchange coupling in 3, to our knowledge, is the highest found in alkoxo-bridged copper(II) complexes.