
%0 Journal Article
%A Tkaczuk, MN 
%A Lincoln, SF 
%T A Proton Magnetic Resonance Study of Ligand Exchange on Tetrakis(tetramethylthiourea)zinc(II) Ion
%J Australian Journal of Chemistry
%D 1979/09/01
%V 32
%N 9
%P 1915-1920
%K 
%R https://doi.org/10.1071/CH9791915
%U https://www.publish.csiro.au/paper/CH9791915 
%X The rate of ligand exchange on the tetrakis(tetramethylthiourea) zinc(II) ion, determined by 1H N.M.R. methods, in CD2Cl2 solution is found to be independent of free-tetramethylthiourea concentration. This is consistent with a dissociative ligand-exchange mechanism being operative. Typically for a solution in which [Zn{S=C(NMe2)2}42+] and [S=C(NMe2)2] were 0·00101 and 0·00376 respectively, kex(200 K) = 16·0±0.6 s-1, &#916;H&#8225; = 64·9±O.8 kJ mol-1 and &#916;S&#8225; = 106±4 J K-1 mol-1 where the observed ligand-exchange rate is given by rate = 4kex[Zn {S=C(NMe2)2}42+] The preparations of [Zn(O=CHNMe2)6](ClO4)2, [Zn{O=CMe(NMe2)}6](Cl04)2, and [Zn{O=C- (NMe2)2}4](ClO4)2 are also reported. The rate of ligand exchange upon these three species in CD2Cl2 solution was found to be in the fast-exchange limit of the N.M.R. time scale. 
