DFT calculations of EPR parameters for copper(II)-exchanged zeolites using cluster models.
The coordination environment of Cu(II) in hydrated copper-exchanged zeolites was explored through the use of density functional theory (DFT) calculations of EPR parameters. Extensive experimental EPR data are available in the literature for hydrated copper-exchanged zeolites. The copper complex in hydrated copper-exchanged zeolites was previously proposed to be [Cu(H(2)O)(5)OH](+) based on empirical trends in tetragonal model complex EPR data. In this study, calculated EPR parameters for the previously proposed copper complex, [Cu(H(2)O)(5)OH](+), were compared to model complexes in which Cu(II) was coordinated to small silicate or aluminosilicate clusters as a first approximation of the impact of the zeolitic environment on the copper complex. Interpretation of the results suggests that Cu(II) is coordinated or closely associated with framework oxygen atoms within the zeolite structure. Additionally, it is proposed that the EPR parameters are dependent on the Si/Al ratio of the parent zeolite.
Ames
William M
WM
Department of Chemistry, The University of Iowa, Iowa City, Iowa 52242, USA.
Larsen
Sarah C
SC
D003198:Computer Simulation; D003300:Copper / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry*; D017641:Zeolites / Q000737:chemistry*
D009942:Organometallic Compounds; D017641:Zeolites; D003300:Copper