Monoarylated Fluoromesitylpalladium Complexes

Monoarylated complexes [PdCl(Fmes)(L‐L)] [Fmes = 2,4,6‐tris(trifluoromethyl)phenyl or fluoromesityl] and trans‐[PdCl(Fmes)L2] have been obtained by arylation of [PdCl2(L‐L)] (L‐L = tmeda) or trans‐[PdCl2L2] (L = SMe2), by splitting the bridging chloro ligands in [Pd(μ‐Cl)(Fmes)(NCMe)]2 {L‐L = 4,4′‐Me2bipy, biquinolyl (2,2′‐biquinoline), OPPhPy2‐N,N′, (OH)(CH3)CPy2‐N,N′, dppe, pte [1,2‐bis(phenylthio)ethane]; L = 4‐pic}, or by substitution of the diolefin in [PdCl(Fmes)(COD)] (L = tBuNC). A 1:1 ratio of [Pd(μ‐Cl)(Fmes)(NCMe)]2 and monodentate ligands affords [PdCl(Fmes)(NCMe)L] (L = 2,6‐lut, 3,5‐lut, PPh3), whereas a 1:1 mixture of [{PdCl(Fmes)(NCMe)}2(μ‐dppe)] and [PdCl(Fmes)(dppe)] is obtained with dppe under mild conditions. The precursor [Pd(μ‐Cl)(Fmes)(NCMe)]2 is generated by boiling under reflux [PdCl(Fmes)(COD)] in MeCN, and has been used to obtain various binuclear monoarylated complexes [Pd(Fmes)(μ‐X)L]2 [X = Br, L = MeCN, P(o‐Tol)3; X = Cl, L = CO, 4‐pic, 3,5‐lut, P(o‐Tol)3]. Other [Pd(Fmes)(μ‐X)L]2 complexes have been obtained from trans‐[PdCl(Fmes)(SMe2)2] (X = Cl, L = tht, SMe2, PPh3) and from K[Pd4(Fmes)4I5] [X = I, L = P(o‐Tol)3]. Despite the steric hindrance imposed by the Fmes ligand (ortho effect), the ligand‐substitution reactions are suggestive of associative mechanisms. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)