A ¹H and ¹⁴N magnetic resonance study of the exchange of acetonitrile on nickel(II)

Abstract

A ¹H and ¹⁴N n.m.r. study of the exchange reaction Ni(MeCN)₆²⁺ ↔ MeCN in MeCN solvent is reported. From the rate law: R = 6k₂₉₈[Ni(MeCN)₆²⁺] the values k₂₉₈ = (3.6 ± 0.6 ) × 10³ and (2.0 ± 0.3) × 10³ s^-1; ΔH^‡ = 59.6 ± 8.8 and 68.4 ± 2.0 kJ rnol^-1; and ΔS^‡ = 23 ± 16.7Jmol^-1 K^-1 and 50 ± 8.0 J mol^-1 K^-1 are derived from ¹H and ¹⁴N data respectively. The apparent discrepancies between the two kinetic data sets, and the modes of relaxation of the ¹H and ¹⁴N nuclei, are discussed.