Characterization of nanosized nickel prepared by surface reactions of Ni-σ-organyl complexes on silica: An electron paramagnetic and ferromagnetic resonance study
✍ Scribed by Helmuth Drevs; Wolfgang Mörke; Jens Jarsetz; Tomasz Bieruta; Herbert Hofmeister
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 108 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0268-2605
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✦ Synopsis
Dispersed atomic nickel(0) is formed during the reaction of the nickel-s-organyl complexes with silanol groups at temperatures below 373 K. That nickel is oxidized to Ni(I) by protons of the silanol groups in a consecutive step. The Ni(I) portion amounts to about 70% w/w of the Ni used. Six different Ni(I) species are detected by electron paramagnetic resonance. They are stabilized by interaction with the silica surface and the organic moieties; they act as anchor ions for the Ni(0) atoms. Ni(0) crystallites stabilized in this way are about 0.5 nm in diameter after a treatment at 373 K. The influence of the Ni(I) ions on the collective, magnetic properties of the clusters is revealed by calculation of ferromagnetic resonance (FMR) spectra using the independent-grain approach according to Schlo ¨mann and Kotyukov. A strain of about 10 GPa is brought about in the nickel crystallites by the interaction with Ni(I) ions.