Dinuclear Palladium(III) Complexes with a Single Unsupported Bridging Halide Ligand: Reversible Formation from Mononuclear Palladium(II) or Palladium(IV) Precursors

Abstract

Stable PdIII: Dinuclear PdIII complexes of the tridentate ligand trimethyltriazacyclononane (Me3tacn) were obtained by one‐electron oxidation of mononuclear PdII precursors. Further oxidation led reversibly to mononuclear PdIV species. The PdII and PdIII complexes are shown to be involved in the catalytic Kharasch addition of polyhaloalkanes to alkenes.

Structural and reactivity comparison of analogous organometallic Pd(iii) and Pd(iv) complexes

“…5 We have also investigated the involvement of Pd III species in aerobicallyinduced C-C bond formation from Pd II precursors 6 and in Kharasch radical additions. 7 Continuing our study of high valent Pd chemistry, herein we report the use of N-methyl ( Me N4) and N-isopropyl ( iPr N4) pyridinophane ligand analogs that lead to the isolation and characterization of analogous mononuclear Pd III and Pd IV complexes. Isolation of these complexes enabled a direct structural and reactivity comparison of the two Pd oxidation states in an identical ligand environment.…”

Organometallic Ni(ii), Ni(iii), and Ni(iv) complexes relevant to carbon–carbon and carbon–oxygen bond formation reactions

“…1a), as well as Pd II/IV complexes, that undergo C–C/C–heteroatom bond formation reactions. 25–40 Recently, a macrocyclic N-based tetradentate ligand PyNMe 3 has been employed by Costas, Company and co-workers to stabilize high-valent intermediate species and has proved to be successful to trap Fe IV/V -oxo species (Fig. 1b) and dinuclear Cu II side-on peroxo species.…”

Aerobic C–C and C–O bond formation reactions mediated by high-valent nickel species

“…[10][11][12][13][14][15][16][17][18][19][20] By comparison, stoichiometric and catalytic Ni-mediated C-heteroatom bond formation reactions have been developed mostly in the past two decades. [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] In the past several years we have employed tetradentate pyridinophane ligands to stabilize uncommon organometallic Pd III/IV and Ni III/IV complexes, [37][38][39][40][41][42][43][44] which can undergo C-C and C-heteroatom bond formation reactions. In addition, we have recently reported the use of the ligand 1,4,7-trimethyl-1,4,7triazacyclonane (Me 3 tacn) to stabilize high-valent Ni III/IV complexes that undergo C-C and C-heteroatom bond formation reactions.…”