Synthesis and characterization of homologous nickel(II) and palladium(II) complexes with biphosphine monoxide ligands Ph2P(CH2)nP(O)Ph2 (n=1-3) and pTol2P(CH2)P(O)pTol2

A series of cationic nickel complexes [( eta(3)-methallyl)Ni(P boolean AND P(O))]SbF6 (1-4) [P boolean AND P(O) =Ph2P(CH2)P(O)Ph-2 (dppmO) (1), Ph2P(CH2)(2)P(O)Ph-2 (dppeO) (2), Ph2P(CH2)(3)P( O)Ph-2 (dpppO)(3), pTol(2)P( CH2)P(O)pTol(2) (dtolpmO) (4)] has been synthesized in good yields by treatment of [( eta(3)-methallyl) NiBr](2) with biphosphine monoxides and AgSbF6. The ligands are coordinated in a bidentate way. Starting from [( eta(3)-all)PdI](2) the cationic complexes [( eta(3)-all)Pd(P boolean AND P(O))]Y (8-14), [P boolean AND P(O)=dppmO, dppeO, dpppO, dtolpmO;Y = BF4, SbF6, CF3SO3, pTolSO(3)] were synthesized id good yields. The coordination mode of the ligand is dependent an the backbone and the anion, revealing a monodentate coordination with dppmO for stronger coordinating anions. The intermediates [(eta(3)-all)Pd(I) (P boolean AND P(O)-kappa(1)-P)] (5-7) [P boolean AND P(O) =dppmO (5), dppeO (6), dtolpmO (7)] were isolated and characterized. Neutral methyl complexes [ (Cl) (Me)Pd(P boolean AND P(O))] (15-18), [P boolean AND P(O = dppmO (15),dppeO (16),dpppO (17),dtolpmO (18)] can easily be obtained in high yields starting from [(cod)PdCl2]. For dppmO two different routes are presented. The structure of [(Me) (Cl)Pd{Ph2P(CH2)P(O)Ph-2-kappa(2)-P,O}]. CH2Cl2 (15) with the chlorine atom trans to phosphorus was determined bi X-ray diffraction. (C) 1998 Elsevier Science S.A. All rights reserved.