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Characterization of nanosized nickel prepared by surface reactions of Ni‐σ‐organyl complexes on silica: An electron paramagnetic and ferromagnetic resonance study
Author(s) -
Drevs Helmuth,
Mörke Wolfgang,
Jarsetz Jens,
Bieruta Tomasz,
Hofmeister Herbert
Publication year - 1998
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/(sici)1099-0739(199805)12:5<321::aid-aoc724>3.0.co;2-e
Subject(s) - silanol , nickel , chemistry , crystallite , electron paramagnetic resonance , paramagnetism , ferromagnetism , ion , crystallography , ferromagnetic resonance , inorganic chemistry , resonance (particle physics) , nuclear magnetic resonance , catalysis , magnetization , organic chemistry , condensed matter physics , atomic physics , magnetic field , physics , quantum mechanics
Dispersed atomic nickel(0) is formed during the reaction of the nickel‐σ‐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 Schlömann and Kotyukov. A strain of about 10 GPa is brought about in the nickel crystallites by the interaction with Ni(I) ions. © 1998 John Wiley & Sons, Ltd.