Mixed-metal assemblies involving ferrocene-naphthyridine hybrids.

Covalent attachment of one and two NP moieties to a ferrocenyl unit provides organometallic ligands 1,8-naphthyrid-2-yl-ferrocene (FcNP) and 1,1'-bis(1,8-naphthyrid-2-yl)ferrocene (FcNP(2)). Coordination of FcNP to transition metal ions Fe(II), Cu(II), Zn(II), and Cd(II) provides [FeCl(2)(kappaN(8)-FcNP)(2)] (1), [Cu(kappaN(8)-FcNP)(2)(NO(3))(2)] (2), [Zn(kappaN(8)-FcNP)(4)]OTf (3), and [Cd(kappaN(8)-FcNP)(2)(kappa(2)N(1),N(8)-FcNP)(2)]BF(4) (4), respectively. Dirhodium(II) compound [Rh(2)(mu-FcNP)(2)(mu-O(2)CCH(3))(2)(H(2)O)]OTf (5) is isolated when acetonitrile-solvated Rh(2)(mu-O(2)CCH(3))(2) is employed as a precursor. Diverse bonding modes of the NP unit, including monodentate, bidentate chelating, or binuclear bridging, are revealed in these FcNP clusters. Metallamacrocycles [M(2)(FcNP(2))(2)]X (M = Cu, X = ClO(4) (6); M = Ag, X = OTf (7)), [PdCl(2)(FcNP(2))] (8), and ZnCl(2)(FcNP(2)) (10) are obtained by the reaction of CuClO(4), AgOTf, Pd(C(6)H(5)CN)(2)Cl(2), and ZnCl(2) with FcNP(2) in 1:1 ratios. Treatment of Cu(I) and FcNP(2) in a 2:1 ratio provides [Cu(2)(FcNP(2))]ClO(4) (9). Molecular structures of compounds 1-10 have been determined by X-ray diffraction studies. Interconversion between 1:1 dimer 6 and 2:1 dimer 9 occurs by the addition of a requisite amount of Cu(I) or FcNP(2). ESI-MS experiments reveal that the predominant species is the 1:1 complex {Cu(FcNP(2))}(1+) in solution for both 6 and 9. Synthesis, structures, mass spectroscopy, and electrochemistry of the transition metal compounds of FcNP and FcNP(2) are discussed.