Sharma Rupali, Zhang Jie, Ohlin C André
School of Chemistry, Monash University, Victoria, Australia.
Dalton Trans. 2015 Nov 28;44(44):19068-71. doi: 10.1039/c5dt03138a. Epub 2015 Oct 22.
The aqueous reaction dynamics of the manganese(II)-functionalised Wells-Dawson polyoxometalate Mn4(H2O)2(P2W15O56)2 has been determined as a function of pH using variable temperature (17)O NMR, and compared with that of the well-studied monomeric manganese(II) hexa-aqua ion, Mn(H2O)6. While the rate of aquo-ligand exchange on the hexa-aqua ion remains independent of pH in the range 3.2-6.0, the rate of water exchange of the polyoxometalate ion varies by a factor of fifteen, from 1.98 × 10(7) s(-1) at pH 3.2 to 1.3 × 10(6) s(-1) at pH 6.0. This decrease in the rate of exchange correlates with the deprotonation of the polyoxometalate framework.
