Synthesis and characterization of homologous nickel(II) and palladium(II) complexes with biphosphine monoxide ligands Ph 2P(CH 2) nP(O)Ph 2 ( n = 1–3) and pTol 2P(CH 2)P(O) pTol 2

Abstract

A series of cationic nickel complexes [( η 3-methally)Ni(P∧P(O))]SbF 6 ( 1–4) [P∧P(O) = Ph 2P(CH 2)P(O)Ph 2 (dppmO) ( 1), Ph 2P(CH 2) 2P(O)Ph 2 (dppeO) ( 2), Ph 2P(CH 2) 3P(O)Ph 2 (dpppO) ( 3), pTol 2P(CH 2)P(O) pTol 2 (dtolpmO) ( 4)] has been synthesized in good yields by treatment of [( η 3-methally)NiBr] 2 with biphosphine monoxides and AgSbF 6. The ligands are coordinated in a bidentate way. Starting from [( η 3-all)PdI] 2 the cationic complexes [( η 3-all)P∧P(O))]Y ( 8–14). [P∧P(O) = dppmO, dppeO, dpppO, dtolpmO;Y = BF 4, SbF 6, CF 3SO 3, pTolSO 3] were synthesized in good yields. The coordination mode of the ligand is dependent on the backbone and the anion, revealing a monodentate coordination with dppmO for stronger coordinating anions. The intermediates [( η 3-all)Pd(I)(P∧P(O)- κ 1- P)] ( 5–7) [P∧P(O) = dppmO ( 5), dppeO ( 6), dtolpmO ( 7)] were isolated and characterized. Neutral methyl complexes [(Cl)(Me)Pd(P∧P(O))] ( 15–18). [P∧P(O) = dppmO ( 15), dppeO ( 16), dpppO ( 17), dtolpmO ( 18)] can easily be obtained in high yields starting from [(cod)PdCl 2]. For dppmO two different routes are presented. The structure of [(Me)(Cl)Pd{;Ph 2P(CH 2-P(O)Ph 2- κ 2- P, O};] · CH 2Cl 2 ( 15) with the chlorine atom trans to phosphorus was determined by X-ray diffraction.