title: New coordination polymers based on the triangular [Cu3(mu3-OH)(mu-pz)3]2+ unit and unsaturated carboxylates.
abstract: By reacting copper(II) acrylate with pyrazole (Hpz), two trinuclear copper derivatives [Cu3(mu3-OH)(mu-pz)3(CH2CHCOO)2(H2O)2(Hpz)], 1, and [Cu3(mu3-OH)(mu-pz)3(CH2CHCOO)2(CH3OH)], 2, are obtained, in water and methanol respectively, while copper(II) methacrylate affords [Cu3(mu3-OH)(mu-pz)3(CH2C(CH3)COO)2], 3, independently from the solvent used. In 1 and 2 two triangular trinuclear units are connected through acrylate bridges forming hexanuclear clusters that, in the case of 2 are further connected through double syn-syn carboxylate bridges, generating a 1-D coordination polymer. In the case of 3 a different 1-D coordination polymer is obtained by alternating syn-syn and syn-anti double carboxylate bridges connecting the trinuclear clusters. In all cases H-bonds contribute both to the stabilization of these arrangements and to the formation of more extended supramolecular networks. Compounds 1-3 are valuable catalysts in the peroxidative oxidation with aqueous H2O2, in MeCN at 25 degrees C, of cycloalkanes (i.e. cyclohexane and cyclopentane) to the corresponding ketones and alcohols (overall yield up to 36%, TON = 36), following a radical mechanism as shown by radical trap experiments, and the effects of various factors are studied. Electrochemical experiments show that the copper(II) centres are reduced to copper(I) and copper(0).
authors: Dip. di Chimica G. Ciamician, Università di Bologna, Italy.
authors: Simone
authors: S
authors: Contaldi
authors: Corrado
authors: C
authors: Di Nicola
authors: Federica
authors: F
authors: Garau
authors: Yauhen Yu
authors: YY
authors: Karabach
authors: Luísa M D R S
authors: LM
authors: Martins
authors: Magda
authors: M
authors: Monari
authors: Luciano
authors: L
authors: Pandolfo
authors: Claudio
authors: C
authors: Pettinari
authors: Armando J L
authors: AJ
authors: Pombeiro