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R studies of coordinatively unsaturated surface compounds on silica gel. II . CO complexes of nickel(II)
Author(s) -
Rebenstorf B.,
Larsson R.
Publication year - 1979
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.19794530617
Subject(s) - nickel , octahedron , chemistry , molecule , torr , adsorption , absorption band , infrared spectroscopy , absorption (acoustics) , crystallography , inorganic chemistry , analytical chemistry (journal) , materials science , organic chemistry , crystal structure , optics , thermodynamics , physics , composite material
The IR spectra of the title compounds show one absorption band due to the stretching vibration of adsorbed CO (2198.5 cm −1 ) at room temperature and low CO pressure (20 Torr CO) and three bands (2180, 2 195 and 2206 cm −1 ) at low temperatures (−70 to −145°C). The first band is assigned to a trans square‐planar complex with two CO molecules and the latter to an octahedral complex with four CO molecules. Using a different preparation method it was possible to obtain also a cis square‐planar complex with two CO molecules (2 181.5 and 2194 cm −1 ). The reduction of the title compounds to nickel(I) and nickel(0) with CO at room or low temperatures was investigated and a reaction mechanism is proposed. Both reactions (conversion to a cis surface complex and the reduction) are explained on the basis of a CO insertion into a Ni(II)O‐ bond, by which a relatively unstable nickel(I) compound is produced (vibration at 1 758 (1 804) cm −1 ).