A novel copper(II)-lanthanum(III) metal organic framework as a selective catalyst for the aerobic oxidation of benzylic hydrocarbons and cycloalkenes

Abstract

The synthesis and structure of a novel heteronuclear Cu-II and La-III metal organic framework (MOF) having pyridinedicarboxylic acid (CuLa-MOF) is reported. The obtained MOF with the formula {[Cu0.5La2(HPDC)(PDC)(2)(SO4)(H2O)(2)]H2O}(n) (PDC: 3,5-pyridinedicarboxylate) has a 3D non-porous lattice with a single type of octahedrally coordinated Cu-II and two distinct nonacoordinated LaIII ions, with sulphate being a linker between the Cu-II and La-III centers. CuLa-MOF exhibits catalytic activity to promote the aerobic autooxidation of benzylic hydrocarbons and the aerobic oxidation of cycloalkenes. Compared with a homogenous catalyst, Cu(OAc)(2), CuLa-MOF, as a heterogeneous catalyst, exhibits similar activity, but the solid is recyclable with some minor decrease in activity from the first to the second catalytic cycle; after which, a steady activity is observed, as determined by the coincidence of temporal evolution of the reaction upon reuse