Dinuclear Ortho-Metalated Palladium(II) Compounds with N,N- and N,O-Donor Bridging Ligands. Synthesis of New Palladium(III) Complexes

作者：Penno Dirk; Estevan Francisco; Fernandez Elena; Hirva Pipsa; Lahuerta Pascual; Sanau Mercedes; Angeles Ubeda Ma

来源：Organometallics, 2011, 30(8): 2083-2094.

DOI：10.1021/om100740q

New dinuclear ortho-metalated palladium(II) compounds with N,N'-diarylformamidinates, Pd(2)[(C(6)H(4))PPh(2)](2)[R'NC(H)NR'](2) (R' = C(6)H(5), 3a; R' = p-CH(3)C(6)H(4), 3h; R' = p-CH(3)OC(6)H(4), 3c) and N,O-donor ligands, Pd(2)[(C(6)H(4))PPh(2)](2)[N,O](2) (N,O = succinimidate (5), phtalimidate (6), 2-hydroxypyridinate (7), acetanilidate (8)) have been synthesized and characterized by NMR spectroscopy and X-ray diffraction methods. The oxidation with iodobenzene dichloride gave new and rare Pd(2)(6+) compounds, Pd(2)[(C(6)H(4))PPh(2)](2)[R'NC(H)NR'](2)Cl(2) (R' = C(6)H(5), 4a; R' = p-CH(3)C(6)H(4), 4b). DFT calculations on the Pd(2)(4+) -> Pd(2)(6+) oxidation reaction show that the substituents on the arnidinate N atoms have a greater effect on the reaction energy than the substituents on the C atom. DFT calculations also confirm that for Pd(2)[(C(6)H(4))PPh(2)](2)[N,O](2) compounds the symmetric isomers with N atoms trans to O atoms are the most stable complexes. The palladium dimers were tested as precursors of catalysts in tandem diboration/arylation/oxidation reactions.

• 出版日期2011-4-25