Synthesis of a Series of Rhodium Complexes, Tp^iPrRh^IL₂ and Tp^iPrRh^III(X)(Y)(MeCN), with the Hydridotris(3,5-diisopropylpyrazolyl)borato Ligand (Tp^iPr) from a Versatile Precursor, (κ³-Tp^iPr)Rh(coe)(MeCN), and Dependence of κ²−κ³ Interconversion Rate of the Tp^iPr Ligand on the Chelate Ring Size

The labile Rh(I) species Tp^iPrRh(coe)(MeCN) (1) was prepared by the reaction of [RhCl(coe)₂]₂ with KTp^iPr followed by crystallization from MeCN. Subsequent treatment of 1 with diphosphines and CO gave square-planar Tp^iPrRh^IL₂-type products via replacement of the coe and MeCN ligands. The Rh(III) complexes Tp^iPrRh(X)(Y)(MeCN) were obtained via oxidative addition of XY and dissociation of the coe ligand. Complex 1 serves as a versatile starting compound for a variety of Rh(I) and Rh(III) complexes containing the Tp^iPr ligand. In addition, it was found that κ²−κ³ interconversion of the diphosphine complexes Tp^iPrRh[Ph₂P(CH₂)_nPPh₂] becomes slower as the chelate ring size increases (n increases).