P(CH2CH2PY)(N)PH3-N (PY = 2-PYRIDYL N = 1, 2, 3) AS CHELATING AND AS BINUCLEATING LIGANDS FOR PALLADIUM

Several neutral palladium(II) complexes of the type [PdRCl(PNn)] with the ligands P(CH2CH2Py)Ph-2 (PN), P(CH2CH2Py)(2)Ph (PN2), and P(CH2CH2 Py)(3) (PN3) have been prepared by reacting the corresponding phosphin es with [Pd-2(mu-Cl)(2)R-2(tht)(2)] (R = C6Cl2F3, C6F5; tht = tetrahyd rothiophene). In all these complexes, the ligands act as bidentate P,N -chelating ligands. Abstraction of the chloride with AgBF4 leads to th e formation of the dimeric compounds [Pd2R2(PN2)(2)](BF4)(2) and [Pd2R 2(PN3)(2)](BF4)(2), in which the PNn ligands act as P,N-chelating and P,N-bridging ligands. The bridges are labile, and exchange experiments on mixtures of the complexes with different R groups show the equilib rium in solution between the dimeric ''pure'' complexes and the mixed complexes [Pd-2(C6F5)(C6Cl2F3)(PNn)(2)](2+). The structure of the comp lex [Pd-2(C6Cl2F3)(2)(P(CH2CH2Py)(2)Ph)(2)](BF4)(2) has been studied b y X-ray diffraction.