title: Paramagnetic species on catalytic surfaces--DFT investigations into structure sensitivity of the hyperfine coupling constants.
abstract: Structure sensitivity of the hyperfine coupling constants was investigated by means of DFT calculations for selected surface paramagnetic species. A *CH2OH radical trapped on silica and intrazeolite copper nitrosyl adducts encaged in ZSM-5 were taken as the examples. The surface of amorphous silica was modeled with a [Si5O8H10] cluster, whereas the zeolite hosting sites were epitomized by [Si4AlO5(OH)10]- cluster. Three different coordination modes of the *CH2OH radical were considered and the isotropic 13C and 1H hyperfine constants of the resultant van der Waals complexes, calculated with B3LYP/6-311G(d), were discussed in terms of the angular deformations caused by hydrogen bonds with the cluster. The magnetic parameters of the eta1-N[CuNO]11 and eta1-O[CuNO]11 linkage isomers were calculated at the BPW91/LanL2DZ and 6-311G(df) level. For the most stable eta1-N adduct a clear dependence of the spin density distribution within the Cu-NO moiety on changes in the Cu-N-O angle and the Cu-N bond distance was observed and accounted for by varying spin polarization and delocalization contributions.
authors.affiliation: Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Cracow, Poland. sojka@chemia.uj.edu.pl
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Sojka
authors.forename: Piotr
authors.initials: P
authors.lastname: Pietrzyk
mesh_terms: D002247:Carbon Isotopes; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D006860:Hydrogen Bonding; D008433:Mathematics; D008956:Models, Chemical; D008958:Models, Molecular; D008962:Models, Theoretical; D009584:Nitrogen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D011522:Protons; D011789:Quantum Theory; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013499:Surface Properties; D017641:Zeolites / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D011522:Protons; D017641:Zeolites; D012822:Silicon Dioxide; D003300:Copper; D009584:Nitrogen; D010100:Oxygen