Complexes of the bidentate ligands Z-PPh2CH2C(But)NNR2(R = Me or H) with rhodium and iridium

Abstract

Treatment of 0.5 equivalent of [{RhCl(CO)₂}₂] with the phosphino dimethylhydrazone Z-PPh₂CH₂C(Bu^t)NNMe₂(L¹) or the phosphino hydrazone Z-PPh₂CH₂C(Bu^t)NNH₂(L²) gave the chelate complexes [[graphic omitted]R₂}](R = Me 1a or H 1b). Complex 1a reacts with another mole of L¹ to give the bis(phosphine)rhodium(I) complex trans-[RhCl(CO)-{PPh₂CH₂C(Bu^t)NNMe₂}₂]2a. The analogous iridium(I) complex 2b was prepared by treating [IrCl(CO)₂(H₂NC₆H₄Me-p)] with 2 mol equivalents of L¹. Complex 2a reacts with [PtCl₂(cod)](cod = cycloocta-1,5-diene) to give a 1:1 mixture of the chelate 1a and [[graphic omitted]-Me₂}]. Treatment of [IrCl(CO)₂(H₂NC₆H₄Me-p)] with 2 equivalents of L² gave the hydridoiridium(III) complex cis-[[graphic omitted]H₂}₂]Cl 3a. Treatment of [{MCl(cod)}₂](M = Rh or Ir) with two equivalents of L¹ in methanol in the presence of NH₄PF₆ gave the cationic complexes [[graphic omitted]Me₂}]PF₆(M = Rh 4a or Ir 4b) in which L¹ is bidentate. When [{MCl(cod)}₂] was treated with 2 equivalents of L¹ in benzene it yielded the neutral complexes [MCl(cod){PPh₂CH₂C(Bu^t)NNMe₂}](M = Rh 5a or Ir 5b) in which L¹ is monodentate through phosphorus. Treatment of [{MCl(cod)}₂] with 2 equivalents of L² in CD₂Cl₂ gave the cationic chelate complexes [[graphic omitted]H₂}]Cl (M = Rh 4c or Ir 4d). Treatment of [{RhCl(cod)}₂] or [{RhCl(C₈H₁₄)₂}₂](C₈H₁₄= cyclooctene) with 2 equivalents of L² per rhodium atom gave the cationic bis(phosphine)rhodium(I) complex [[graphic omitted]H₂}₂]Cl 6. Treatment of [RhCl(PPh₃)₃] with 1 equivalent of L¹ in C₆D₆ gave the Wilkinson-type complex [[graphic omitted]Me₂}]7, which readily reacts with dioxygen to give the adduct cis-[[graphic omitted]Me₂}]8. The rhodium(III) complex 8 reacts with sulfur dioxide to give the rhodium(III) sulfate cis-[[graphic omitted]Me₂}]9. Treatment of [{MCl(C₈H₁₄)₂}₂] with 2 equivalents of L¹ per rhodium atom gave the bis(phosphine) complexes cis-[[graphic omitted]Me₂}{PPh₂CH₂C(Bu^t)NNMe₂}](M = Rh 10a or Ir 10b), containing one chelate and one monodentate phosphine ligand. These complexes reacted rapidly with dioxygen to give corresponding dioxygen adducts cis-[[graphic omitted]Me₂}{PPh₂CH₂C(Bu^t)NNMe₂}](M = Rh 11a or Ir 11b). Proton, ³¹P-{¹H} and some ¹³C-{¹H} NMR data are given.