Isotopic exchange and racemization of some tris-β-diketonato complexes of typical elements of Groups III and IV

K. Saito
1974 Pure and Applied Chemistry  
In organic solvents the isotopic exchange between ß-diketone-14 C and its tris complexes with Al 111 , GaiD and Inm proceeds at a greater rate in the order given, and with decrease in pK 11 of the Iigand. There seems to be a rapid equilibrium between the complex and an intermediate with one of the ligands as unidentate, and the break of the remaining bond appears to be the rate 5 determining step. Similar tris:complexes of Sirv and GeiV give an immeasurably slow rate of such an exchange up to
more » ... °C. They undergo racemization in dehydrated organic solvents and the rate is govemed by the ease of M-0 bond break and the probability of intramolecular rearrangement to give a symmetrical intermediate. Comparison of the order of ease of intermolecular isotopic exchange with that of intramolecular site-exchange of a variety of ß-diketonato complexes reveals a dominating contribution of the charge of the central ion upon the intermolecular change.
doi:10.1351/pac197438030325 fatcat:72e5pldxnrhavnwsw26duvxsq4