Submitted by Joshua Telser / Roosevelt University on Fri, 04/23/2021 - 12:37

I scanned through the forums that came up with "kinetics" and could not find what I am looking for, but I know VIPEr people know the answer to this question: I am looking for an example of kinetics versus thermodynamics control of an ambidentate ligand, i.e., M + XY ---> M-XY initially (kinetics control) ---> M-YX (eventually, thermodynamic product). Any examples of M and XY (obviously "XY" is generic, could be SCN-, et al.)? I would also add into this question a case where M + L ---> M-L in one geometry initially ----> M-L in another geometry eventually, so maybe something like MX4 sq pl + L --> MX4L sq pyr ---> M4XL tbp (this is not a ligand substitution, i.e., MX4 + L ---> [MX4L] ---> MX3L + X, but a kinetics geometry versus a thermodynamic one). Thanks.

Anthony L. Fernandez / Merrimack College

Joshua, the classic example is [Co(NH3)5(ONO)]2+ vs [Co(NH3)5(NO2)]2+. If I recall, the nitrito isomer is formed first, and then upon heating if converts to the nitro isomer. You can see the difference in the IR spectra and crystal structures are available for both linkage isomers.

Fri, 04/23/2021 - 16:40 Permalink