A Proton Magnetic Resonance Study of Ligand Exchange on the Pentakis (N-formylpyrrolidine)dioxouranium (VI) Ion
Keyword(s):
Rate Law
◽
Pentakis(N-formylpyrrolidine)dioxouranium(VI) perchlorate, [UO2(fpr)5] (ClO4)2, has been isolated from solution. In the presence of excess free fpr the greatly predominant species in CD2Cl2 solutions is [UO2(fpr)5]2+, as shown by 1H N.M.R. spectroscopy, and fpr exchange is characterized by a two term rate law: exchange rate = 5(k1+ k2[fpr])[UO2(fpr)52+] It is found that k1(220 K) = 42�6�0�5 s-1, ΔH‡ = 30�7�1�4 kJ mol-1 and ΔS‡ = -71�6�6�3 J K-1 mol-1, and k2(220 K) = 369�20 dm3 mol-1 s-1, ΔH‡ = 30�5�1�0 kJ mol-1 and ΔS‡ = -54�9�5�0 J K-1 mol-1. The mechanistic implications of these data are discussed.
1982 ◽
Vol 86
(3)
◽
pp. 221-225
◽
1980 ◽
pp. 699
◽