Quantitative 2D EXSY and Dynamic <SUP>19</SUP>F-NMR Studies of the Dynamic Behaviour of the Bidentate Chelate Complex Ga(fox)<INF>3</INF> (fox = 5-fluoro-8-hydroxyquinoline)

The rates of intramolecular rearrangement of the meridional isomer of the metal tris-chelate complex [Ga(fox)<INF>3</INF>, fox = 5-fluoro-8-hydroxyquinoline] in DMF solution were measured using 1D NMR line shape analysis and 2D EXSY spectra. The rates of exchange k<INF>ab</INF>, k<INF>bc</INF> and k<INF>ac</INF> between the three non-equivalent ligands a, b and c were determined. The values of the activation parameters were obtained. ΔH^‡ was 70.6 kJ mol^–1 for all the rate constants. ΔS^‡ was different in each of the three cases: ΔS<STACK>^‡<INF>ab</INF></STACK>, ΔS<STACK>^‡<INF>bc</INF></STACK> and ΔS<STACK>^‡<INF>ac</INF></STACK> were 27.7, 28.5 and 34.6 J K^–1 mol^–1 respectively. The interpretation of these data was related to the discrimination of different twist processes (Bailar and Rây–Dutt) for intramolecular rearrangement of the tris-chelate complex.