| Abstract |
Two new coordination compounds with tetracopper(II) cores, namely, a 1D coordination polymer, [Cu-4(mu(4)-H(2)edte)(mu(5)-H(2)edte)(sal)(2)](n)center dot 10(n)H(2)O (1), and a discrete 0D tetramer, [Cu-4(mu(4)-Hedte)(2)(Hpmal)(2)(H2O)]center dot 7.5H(2)O (2), were easily self-assembled from aqueous solutions of copper(II) nitrate, N,N,N ,N -tetrakis(2-hydroxyethyl)ethylenediamine (H(4)edte), salicylic acid (H(2)sal), or phenylmalonic acid (H2pma). The obtained compounds were characterized by IR and electron paramagnetic resonance spectroscopy, thermogravimetric and elemental analysis, and single-crystal X-ray diffraction. In addition to different dimensionalities, their structures reveal distinct single-open [Cu-4(mu(2)-O)(mu(3)-O)(3)] (in 1) or double-open [Cu-4(mu(2)-O)(2)(mu(3)-O)(2)] (in 2) cubane cores with 3M4-1 topology. In crystal structures, numerous crystallization water molecules are arranged into the intricate infinite 1D \(H2O)(18)\(n) water tapes (in 1) or discrete (H2O)(9) clusters (in 2) that participate in multiple hydrogen-bonding interactions with the metal-organic hosts, thus extending the overall structures into very complex 3D supramolecular networks. After simplification, their topological analysis revealed the binodal 6,10- or 6,8-connected underlying 3D nets with unique or rare 6,8T2 topology in 1 and 2, respectively. The magnetic properties of 1 and 2 were investigated in the 1.8-300 K temperature range, indicating overall antiferromagnetic interactions between the adjacent Cu(II) ions within the [Cu4O4] cores. The obtained compounds also act as bioinspired precatalysts for mild homogeneous oxidation, by aqueous hydrogen peroxide at 50 degrees C in an acidic MeCN/H2O medium, of various cyclic and linear C-5-C-8 alkanes to the corresponding alcohols and ketones. Overall product yields of up to 21\% (based on alkane) were achieved, and the effects of various reaction parameters were studied. |
