Trimethylplatinum(IV) complexes of dithiocarbamato ligands: an experimental NMR study on the barrier to C–N bond rotation
作者:Peter J. Heard、Kenneth Kite、Julie Søgaard Nielsen、Derek A. Tocher
DOI:10.1039/b000264j
日期:——
The trimethylplatinum(IV) complexes of a number of dithiocarbamato ligands have been prepared. The complexes are dimeric in the solid state and in solution, with the ligands acting in both a bridging and chelating fashion. Restricted rotation about the ligand CâN bonds in solution leads to the formation of four rotomers. The kinetics of the restricted rotation was measured by a variety of dynamic NMR techniques in the slow and intermediate exchange regimes. Two distinct processes are observed, namely the independent rotation about each CâN bond and correlated rotation about both CâN bonds. The free energies of activation, which are strongly dependent on the nature of the ligand substituents, are in the range 65â88 kJ molâ1 at 298 K. The origins of the barrier to rotation and the effects of the nitrogen substituents are discussed. The crystal structures of fac-[PtMe3(Me2NCS2)]2 and fac-[PtMe3(Ph(H)NCS2)]2 are reported.