Monoarylated fluoromesitylpalladium complexes

Monoarylated complexes [PdCl(Fmes)(L-L)] [Fmes = 2,4,6-tris(trifluoromethyl)phenyl or fluoromesityl] and trans-[PdCl(Fmes)L-2] 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(mu-Cl)(Fmes)(NCMe)](2) ILL = 4,4'-Me(2)bipy, 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(mu-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)(mu-dppe)] and [PdCl(Fmes)(dppe)] is obtained with dppe under mild conditions. The precursor [Pd(mu-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)(mu-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)(mu-X)L](2) complexes have been obtained from trans[PdCI(Fmes)(SMe2)(2)] (X = Cl, L = tht, SMe2, PPh3) and from K[Pd-4(Fmes)(4)I-5] [X = 1, L = P(o-Tol)(3)]. Despite the steric hindrance imposed by the Fines ligand (ortho effect), the ligand-substitution reactions are suggestive of associative mechanisms.