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New E-unidentate [Ph2P(O)NP(E)Ph2]− (E=S or Se) complexes of palladium(II) and platinum(II)

2000; Elsevier BV; Volume: 19; Issue: 6 Linguagem: Inglês

10.1016/s0277-5387(00)00311-9

1873-3719

Martin B. Smith, Alexandra M. Z. Slawin,

Ferrocene Chemistry and Applications

Metathesis of the monochloro metal(II) complexes [MCl(dien)]Cl (M=Pd or Pt; dien=diethylenetriamine) with K[Ph2P(O)NP(E)Ph2] (E=S or Se) or K[Ph2P(O)NPPh2] (prepared in situ from Ph2P(O)NHPPh2/KOBut) in methanol gave the cationic, mononuclear compounds [M{Ph2P(O)NP(E)Ph2-E}(dien)]+ or [M{Ph2P(O)NPPh2-P}(dien)]+, isolated as their hexafluorophosphate salts. Ligand substitution reactions of the dichlorometal(II) precursors [MCl2(N∼N)] (M=Pd or Pt; N∼N=ethane-1,2-diamine, 1,2-diaminocyclohexane) with K[Ph2P(O)NP(E)Ph2] or K[Ph2P(O)NPPh2] gave the neutral bis substituted compounds [M{Ph2P(O)NP(E)Ph2-E}2(N∼N)] or [M{Ph2P(O)NPPh2-P}2(N∼N)] in high yields (63–89%). Reaction of the unsymmetrical palladium(II) compound [PdCl2(ampy)] (ampy=2-aminomethylpyridine) with K[Ph2P(O)NP(E)Ph2] gave [Pd{Ph2P(O)NP(E)Ph2-E}2(ampy)], analogous to the recently described compound [Pd{Ph2P(O)NP(E)Ph2-E}2(en)], in which both [Ph2P(O)NP(E)Ph2]− ligands are exclusively E-monodentate bound. In contrast, transmetallation of K[Ph2P(O)NP(E)Ph2] with [PdCl2(tmeda)] (tmeda=N,N,N′,N′-tetramethylethylenediamine) gave only the O,E-chelate monocationic complexes [Pd{Ph2P(O)NP(E)Ph2-O,E}(tmeda)]PF6 and not [Pd{Ph2P(O)NP(E)Ph2-E}2(tmeda)]. Under similar reaction conditions the symmetrical anions [Ph2P(E)NP(E)Ph2]− (E=S or Se) gave, without exception, the known bis homoleptic complexes [M{Ph2P(E)NP(E)Ph2-E,E′}2] (M=Pd or Pt) with displacement of all chloride and amine ligands. All new compounds have been characterised by a combination of multinuclear NMR (1H, 31P{1H}, 195Pt{1H}), IR spectroscopy and elemental analyses. Furthermore, the X-ray crystal structures of five compounds have been determined and reveal a range of intermolecular and intramolecular hydrogen bonding contacts. There is also evidence for π-delocalisation within the E–P–N–P–O and P–N–P–O backbones of the E-ligating or O,E-chelating ligand.