title: A hemilabile binucleating pincer ligand for self-assembly of coordination oligomers and polymers.
abstract: The bis(PNP)-donor pincer ligand 1,4-C(6)H(4){N(CH(2)CH(2)PPh(2))(2)}(2), 1, contains weakly basic nitrogen donor atoms because the lone pairs of electrons are conjugated to the bridging phenylene group, and this feature is used in the synthesis of oligomers and polymers. The complexes [Pd(2)X(2)(mu-1)](OTf)(2), X=Cl, Br or OTf, contain the ligand 1 in bis(pincer) binding mode (mu-kappa(6)-P(4)N(2)), but [Pd(4)Cl(6)(mu(3-)1)(2)]Cl(2) contains the ligand in an unusual unsymmetrical mu(3)-kappa(5)-P(4)N binding mode. The bromide complex is suggested to exist as a polymer [{Pd(2)Br(4)(mu(4)-1)}(n)] with the ligands 1 in mu(4)-kappa(4)-P(4) binding mode. The methylplatinum(II) complexes [Pt(2)Me(4)(mu-1)] and [Pt(2)Me(2)(mu-1)](O(2)CCF(3))(2) contain the ligand in mu-kappa(4)-P(4) and mu-kappa(6)-P(4)N(2) bonding modes, while the silver(I) complex [Ag(2)(O(2)CCF(3))(2) (mu-1)] contains the ligand 1 in an intermediate bonding mode in which the nitrogen donors are very weakly coordinated. The complexes [Pd(2)(OTf)(2)(mu-1)](OTf)(2) and [Ag(2)(O(2)CCF(3))(2)(mu-1)] react with 4,4'-bipyridine to give polymers [Pd(2)(micro-bipy)(mu-1)](OTf)(4) and [Ag(2)(mu-bipy)(mu-1)](O(2)CCF(3))(2).
authors.affiliation: Department of Chemistry, University of Western Ontario, London, Canada N6A 5B7.
authors.forename: Chang-Qiu
authors.initials: CQ
authors.lastname: Zhao
authors.forename: Michael C
authors.initials: MC
authors.lastname: Jennings
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Puddephatt