Speciation and structure of cobalt carbonyl and nitrosyl adducts in ZSM-5 zeolite investigated by EPR, IR and DFT techniques

摘要

Adsorption of CO and NO on CoZSM-5 leads to the formation of various carbonyl and nitrosyl adducts. Their speciation and structure was studied by joint use of EPR and IR spectroscopies corroborated by DFT calculation. Depending on the temperature and pressure the following species were observed: {CoCO}~7, {Co(CO)_3}~7 carbonyls and {CoNO}~8 {Co(NO)_2}~9, {CoNO}~7 nitrosyls. The bounding of CO and NO leads to nucleophilic activation of the diatomic ligands with distinctly different electron density redistribution within the Co―CO and Co―NO moieties.