Isolation and structures of rhodium(III) complexes with cyclometalated bis(dialkylthiophosphoryl)imides via intramolecular C–H activation

• Four rhodium complexes with dithioimidodiphosphinate ligand were prepared.
• The synthesized complexes were characterized by X-ray crystallography.
• C–H activation of [N(R2PS)2]− (R = alkyl) with Rh2(OAc)4 was observed.
• Break of Rh–Rh bond and oxidation of Rh(II) to Rh(III) species was observed.

Treatment of dirhodium(II) tetra-acetate Rh2(OAc)4 with HN(Ph2PS)2 in refluxing tetrahydrofuran (THF) yielded a typical mononuclear Rh(III) complex Rh[N(Ph2PS)2]3 (1). Reaction of Rh2(OAc)4 with HN(iPr2PS)2 in a similar condition resulted in the mixed Rh(III) complexes Rh[N(iPr2PS)2)]3 (2) in a major product and Rh[N(iPr2PS)2][κ2S,κC-N(iPr2PS)(iPr(C3H6)PS)] (3) in a minor product, while the similar reaction by use of HN(tBu2PS)2 led to isolation of complex Rh[N(tBu2PS)2][κ2S,κC-N(tBu2PS)(tBu(C4H8)PS)] (4) as a sole product. Novel C–H bond activation of one methyl group in the ligands [N(R2PS)2]− (R = iPr, tBu) was observed in complexes 3 and 4, which was further confirmed by the analysis of X-ray crystallography along with other spectroscopic properties.

Two σ-alkyl rhodium(III) complexes Rh[N(iPr2PS)2][κ2S,κC-N(iPr2PS)(iPr(C3H6)PS)] and Rh[N(tBu2PS)2][κ2S,κC-N(tBu2PS)(tBu(C4H8)PS)] containing ortho-metalated bis(dialkylthiophosphoryl)imide ligand were isolated via C–H activation of [N(R2PS)2]− (R = iPr, tBu) and oxidation of dirhodium(II) tetraacetate Rh2(OAc)4.Figure optionsDownload as PowerPoint slide