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Volumes of Activation for Dimethylsulfoxide and N,N-Dimethylformamide Exchange with Hexasolvates of Aluminium (III) and Gallium (III) Ions in Deuterionitromethane Solution

✍ Scribed by Claude Ammann; Peter Moore; André E. Merbach; Colin H. McAteer


Publisher
John Wiley and Sons
Year
1980
Tongue
German
Weight
552 KB
Volume
63
Category
Article
ISSN
0018-019X

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✦ Synopsis


Abstract

High‐pressure ^1^H‐NMR. has been used to determine volumes of activation (Δ__V__#) for solvent exchange with [M(S)~6~]^3+^ ion (M = Al(III), Ga(III); S = dimethylsulfoxide (DMSO) and N,N‐dimethylformamide (DMF)) in [^2^H]~3~‐nitromethane solution. For Al(III),Δ V# = + 15.6 ± 1.4 (S = DMSO, 358.5 K) and Δ__V__# = + 13.7 ± 1.2 cm^3^mol^−1^ (S = DMF, 354.5 K), whilst for Ga(III), Δ__V__# = + 13.1 ± 1.0 (S = DMSO, 334.6 K) and Δ__V__# = +7.9 ± 1.6 cm^3^mol^−1^ (S= DMF, 313.8 K). Variable temperature studies over a temperature range of 107.2 K (Al(III)) and 101.1 K (Ga(III)) were carried out for solvent exchange with [M(DMF)~6~]^3+^ ions in [^2^H]~3~‐nitromethane solution, using stopped‐flow NMR, and conventional linebroadening, and gave Δ__H__# = 88.3 ± 0.9 and 85.1 ± 0.6 kJ+ mol^−1^, and Δ__S__# = 28.4 ± 2.7 and 45.1 ± 1.9 JK^−1^ mol^−1^ for Al(III) and Ga(III) ions respectively. All of these results are consistent with dissociative modes of activation.