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 {[Cu_0.5La₂(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 La^III 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.