Mixed-Metal Coordination Polymers and Molecular Squares Based on a Ferrocene-Containing Multidentate Ligand 1,2-Di(4-pyridylthio)ferrocene

Various metalloligands and inorganic–organic hybrid bridging ligands have been incorporated in polynuclear complexes and bimetallic coordination polymers. Ferrocene, exhibiting redox activity and facile chemical modification, is a versatile metalloligand component. However, most metal complexes with ferrocene-containing ligands form discrete low-dimensional chelate complexes or coordination polymers. Thus, we designed and synthesized ferrocene-based multidentate ligands, 1,2-di­(4-pyridylthio)­ferrocene (<b>L1</b>) and 1,2-di­(2-pyridylthio)­ferrocene (<b>L2</b>). Here we report the synthesis and structures of molecular square complexes and coordination polymers containing <b>L1</b>, which reacted with M­(hfac)₂ (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate) and AgCF₃SO₃ to yield molecular square complexes [M­(hfac)₂­(<b>L1</b>)]₂­·2C₆H₅CH₃ [M = Ni (<b>1</b>) and Co (<b>2</b>)] and [Ag­(CF₃SO₃)­(<b>L1</b>)­(H₂O)_0.5]₂­·2CH₂Cl₂·H₂O (<b>3</b>). The molecular square units comprise two metal ions bridged by two ligands. Isomorphic complexes <b>1</b> and <b>2</b> accommodate two toluene molecules above and below the molecular square. <b>L1</b> reacted with Cu­(hfac)₂ and CuI to yield zigzag, {[Cu­(hfac)₂(<b>L1</b>)]}_<i>n</i>­·0.25<i>n</i>(CH₂Cl₂) (<b>4</b>), and ribbon-shaped, {[Cu₄I₄(<b>L1</b>)₂]}_<i>n</i> (<b>5</b>), coordination polymers. In <b>4</b>, <b>L1</b> behaves as a bidentate <i>N</i>,<i>N</i>-ligand bridging the Cu^II ions, while in <b>5</b> it acts as a tridentate <i>S</i>,<i>N</i>,<i>N</i>-ligand linking the stepped-cubane Cu₄I₄ units. <b>L1</b> reacted with AgX to form two-dimensional coordination polymers {[Ag­(ClO₄)­(<b>L1</b>)]}_<i>n</i> (<b>6</b>) and {[Ag­(<b>L1</b>)]­PF₆}_<i>n</i> (<b>7</b>), in which it acted as a tetradentate <i>S</i>,<i>S</i>,<i>N</i>,<i>N</i>-ligand. These complexes have topologies based on multidentate coordination of 1,2-substituted <b>L1