The Structure of Monomeric Hydroxo-CuIISpecies in Cu-CHA. A Quantitative Assessment

Abstract

Using EPR and HYSCORE spectroscopies in conjunction with ab initio calculations, we assess the structure of framework-bound monomeric hydroxo-CuIIin copper-loaded chabazite (CHA). The species is an interfacial distorted square-planar [CuIIOH(O-8MRs)3] complex located at eight-membered-ring windows, displaying three coordinating bonds with zeolite lattice oxygens and the hydroxo ligand hydrogen-bonded to the cage. The complex has a distinctive EPR signature with g = [2.072 2.072 2.290], CuA= [30 30 410] MHz, and HA = [-13.0 -4.5 +11.5] MHz, distinctively different from other CuIIspecies in CHA.