The interaction of CO, N-2 and NO with Cu cations in ZSM-5: quantum chemical description and IR study

In this paper we study the properties of Cu ions and their interactions wit h diatomic molecules in Cu-exchanged ZSM-5. We present DFT quantum chemical calculations for models composed of the Cu site and a diatomic molecule ac companied by IR investigations for various forms of CuZSM-5. Two series of calculations with density functional theory have been undertaken in order t o investigate the influence of zeolitic framework on properties of exchange d cations: (i) for small models built of free mono- and divalent copper cat ion interacting with CO, N-2 and NO and (ii) 5- or 6-member ring models of ZSM-5 hosting the cation and a diatomic molecule. Comparison of calculated and experimental IR X-Y frequencies supports our model and brings some insi ght into the activation mechanism.