title: Tri(pyridylmethyl)phosphine: the elusive congener of TPA shows surprisingly different coordination behavior.
abstract: Tri(pyridylmethyl)phosphine (TPPh), the remarkably elusive congener of tri(pyridylmethyl)amine (TPA), has been prepared, as well as the relative tri(N-methyl-pyridylamino)phosphine (TPAMP). The coordination properties of these new ligands have been evaluated for chromium(III), iron(II), and ruthenium(II) complexes and compared with the related TPA complexes. In all cases, a different coordination behavior has been observed whereby TPPh and TPAMP always act as tridentate ligands. A chromium(III) complex [Cr(TPPh)Cl3] has been prepared, which has shown low ethylene oligomerization activity. Octahedral low spin iron(II) complexes [Fe(TPPh)2](2+) and [Fe(TPAMP)2](2+) were obtained with two ligands bound to the metal center. Ruthenium(II) chloro complexes of TPA and TPPh undergo ligand exchange reactions in acetonitrile, and the ruthenium(II) complex [Ru(MeCN)2(TPA)](2+) can be oxidized by m-CPBA in acetonitrile to give a transient ruthenium(IV) oxo complex [Ru(O)(MeCN)(TPA)](2+). Attempts to generate high valent ruthenium(IV) oxo TPPh or TPAMP complexes could not be achieved, probably due to insufficient stabilization by these strong field ligands.
authors.affiliation: Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AY, United Kingdom.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Whiteoak
authors.forename: James D
authors.initials: JD
authors.lastname: Nobbs
authors.forename: Evgeny
authors.initials: E
authors.lastname: Kiryushchenkov
authors.forename: Sandro
authors.initials: S
authors.lastname: Pagano
authors.forename: Andrew J P
authors.initials: AJ
authors.lastname: White
authors.forename: George J P
authors.initials: GJ
authors.lastname: Britovsek