Self-assembled two-dimensional water-soluble dipicolinate Cu/Na coordination polymer: Structural features and catalytic activity for the mild peroxidative oxidation of cycloalkanes in acid-free medium

The new water-soluble 2D Cu/Na coordination polymer [Cu(mu-dipic)(2){Na-2(mu-H2O)(4)}](n)center dot 2nH(2)O (1) has been synthesized by self-assembly in aqueous medium from copper(II) nitrate, dipicolinic acid (H(2)dipic) and sodium hydroxide in the presence of triethanolamine. It has been characterized by IR spectroscopy, FAB(+)-MS, elemental and single-crystal X-ray diffraction analyses, the latter featuring a layered 2D metal-organic structure that is extended to a 3D supramolecular assembly by extensive hydrogen bonding between adjacent layers and involving crystallization water molecules. Compound 1 has been shown to act as a catalyst precursor for the peroxidative oxidation of cyclohexane and cyclopentane to the corresponding cyclic ketones and alcohols by aqueous H2O2 in MeCN solution and in the absence of acid additives. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).