Nitrogen-14 magnetic resonance study of the exchange of acetonitrile on copper(II) complexes
- 1 January 1974
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 3,p. 281-284
- https://doi.org/10.1039/dt9740000281
Abstract
The kinetic parameters, determined by 14N n.m.r., for the exchange of acetonitrile are: Cu(MeCN)6 2+, kex(228 K) 1·6 × 107 s–1; Cu(tren)(MeCN)2+, kex(228 K)=(5·1 ± 0·7)× 103 s–1, ΔH‡= 45 ± 4 kJ mol–1, and ΔS‡= 26 ± 16 J mol–1 K–1; Cu(trenol)(MeCN)2 2+, kex(228 K)=(8·0 ± 2·0)× 104 s–1, ΔH‡= 26 ± 8 kJ mol–1 and ΔS‡=–34 ± 32 J mol–1K–1; and Cu(Me6tren)(MeCN)2+, kex(228 K) < 102 s–1, where in all cases kex refers to the exchange at a single site. The kinetic data are discussed in terms of a model whereby the rapidity of exchange on Cu(MeCN)6 2+ is attributed at least partially to a dynamic Jahn–Teller effect, and the reduction in lability upon co-ordination of polydentate ligands is due to elimination of this exchange pathway.Keywords
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