Solvation of silver ions in mixed methyl cyanide + water and methyl cyanide + methanol systems. Radiation and electron spin resonance study
- 1 January 1980
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases
- Vol. 76, 244-255
- https://doi.org/10.1039/f19807600244
Abstract
Exposure of solutions of silver perchlorate in methyl cyanide to 60Co γ-rays at 77 K gave Ag0 centres with a reduced silver hyperfine coupling indicative of electron delocalisation on to solvent molecules. Extra splitting into 9 features separated by 6 G established the presence of four equivalent solvent ligands coordinated via nitrogen. This shows that Ag+ is solvated by four MeCN molecules and that electron addition does not cause desolvation at 77 K. A similar pattern of 14N hyperfine features for the AgII centre establishes the presence of four strongly coupled 14N nuclei and the form of the g and A(109Ag+107Ag) hyperfine components showed that a square planar arrangement of ligands was probably achieved at 77 K. Addition of water or methanol had little effect on the e.s.r. spectra up to ≈ 0.5 mole fraction (MF) of protic solvent, showing that Ag+ is solvated preferentially by methyl cyanide. However, in the 0.45–0.90 MF region (D2O) a new species exhibiting hyperfine coupling to only one 14N nucleus and a greatly increased 109Ag/107Ag hyperfine coupling was detected, whose concentration increased on warming above 77 K. This is thought to be formed from Ag+(H2O)3(MeCN) ions by loss of water following electron addition. Also, an atom-like Ag0 centre was detected in this mole fraction range. Other species detected by e.s.r. spectroscopy included a species with A(109Ag)= 180 G, thought to be [Ag—C(Me)N], and a species with A(109Ag)= 130 G, thought to be [Ag[graphic omitted]CH2OH]+.Keywords
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