Supramolecular Networks Using Ferrocenyl Ditriazole and Diimidazole Bridges

Reactions of acids with naphthyridine-functionalized ferrocenes: protonation and metal extrusion

Reaction of 1,8-naphthyrid-2-yl-ferrocene (FcNP) with a variety of acids affords protonated salts at first, whereas longer reaction time leads to partial demetalation of FcNP resulting in a series of Fe complexes. The corresponding salts [FcNP·H][X] (X = BF(4) or CF(3)SO(3) (1)) are isolated for HBF(4) and CF(3)SO(3)H. Reaction of FcNP with equimolar amount of CF(3)CO(2)H for 12 h affords a neutral complex [Fe(FcNP)(2)(O(2)CCF(3))(2)(OH(2))(2)] (2). Use of excess acid gave a trinuclear Fe(II) complex [Fe(3)(H(2)O)(2)(O(2)CCF(3))(8)(FcNP·H)(2)] (3). Three linear iron atoms are held together by four bridging trifluoroacetates and two aqua ligands in a symmetric fashion. Reaction with ethereal solution of HCl afforded [(FcNP·H)(3)(Cl)][FeCl(4)](2) (4) irrespective of the amount of the acid used. Even the picric acid (HPic) led to metal extrusion giving rise to [Fe(2)(Cl)(2)(FcNP)(2)(Pic)(2)] (5) when crystallized from dichloromethane. Metal extrusion was also observed for CF(3)SO(3)H, but an analytically pure compound could not be isolated. The demetalation reaction proceeds with an initial proton attack to the distal nitrogen of the NP unit. Subsequently, coordination of the conjugate base to the electrophilic Fe facilitates the release of Cp rings from metal. The conjugate base plays an important role in the demetalation process and favors the isolation of the Fe complex as well. The 1,1'-bis(1,8-naphthyrid-2-yl)ferrocene (FcNP(2)) does not undergo demetalation under identical conditions. Two NP units share one positive charge causing the Fe-Cp bonds weakened to an extent that is not sufficient for demetalation. X-ray structure of the monoprotonated FcNP(2) reveals a discrete dimer [(FcNP(2)·H)](2)[OTf](2) (6) supported by two N-H···N hydrogen bonds. Crystal packing and dispersive forces associated with intra- and intermolecular π-π stacking interactions (NP···NP and Cp···NP) allow the formation of the dimer in the solid-state. The protonation and demetalation reactions of FcNP and FcNP(2) with a variety of acids are reported.

Heterobimetallic metal-complex assemblies constructed from the flexible arm-like ligand 1,1'-bis[(3-pyridylamino)carbonyl]ferrocene: structural versatility in the solid state

The bidentate ferrocenyl sandwich molecule 1,1'-bis[(3-pyridylamino)carbonyl]ferrocene (3-BPFA) has been employed as an organometallic ligand in reactions with a series of transition metal salts to construct heterobimetallic architectures. X-ray crystallographic characterization reveals that the crystal packing of free ligand 3-BPFA induces spontaneous resolution of helical chains via intermolecular hydrogen bonds. By combining the flexibility from the arm-like molecule (3-BPFA) with the variation of the coordination property from different metal ions and/or the different counteranions, five different types of architectures are prepared: one octahedral coordination cage (copper(II) complex 1); two discrete pseudocapsules for combination of chlorine anions (nickel(II) complex 2 and cobalt(II) complex 3); two dimers with metal-metal interactions (silver(I) complexes 4 and 5); one macrocyclic complex (mercury(II) complex 6); and five two-dimensional mixed-metal-organic frameworks (M'-MOFs) (zinc(II), cadmium(II), and mercury(II) complexes 7-11). The structures of all complexes are characterized in detail by IR, elementary analysis, and single-crystal X-ray diffraction analysis. The factors inducing the structure variation among the complexes are discussed by taking account of the coordination geometry of different metal ions, the span angle between the two "arms", and the coordination mode of the 3-BPFA ligand.

catena-Poly[[diaqua-dichlorido-manganese(II)]-μ-1,1'-bis-(1H-1,2,4-triazol-1-ylmeth-yl)ferrocene]

In the title complex, [FeMn(C(8)H(8)N(3))(2)Cl(2)(H(2)O)(2)](n), the Mn(II) atom, located on an inversion center, is octa-hedrally coordinated by two N atoms from two adjacent 1,1'-bis-(1H-1,2,4-triazol-1-ylmeth-yl)ferrocene (btmf) ligands and two Cl atoms forming the equatorial plane, with the axial positions occupied by two O atoms of coordinated water mol-ecules. The btmf ligands link adjoining Mn(II) atoms into a zigzag chain along the a axis. The crystal structure is stabilized by inter-molecular O-H⋯N hydrogen bonds, which link the chains, forming a two-dimensional layer parallel to (10); O-H⋯Cl inter-actions link the layers, forming a three-dimensional network.

Self-assembled hetero-bimetallic coordination cage and cation-clusters with µ2-Cl bridging using a flexible two-arm ferrocene amide linker

One flexible, discrete coordination cage [Cu(2)(3-BPFA)(4)(H(2)O)(2)](ClO(4))(4).4CH(3)OH (), and two cation-clusters with micro(2)-Cl bridging [Ni(2)(micro-Cl)(3-BPFA)(4)(H(2)O)(2)](ClO(4))(3) () and [Co(2)(micro-Cl)(3-BPFA)(4)(H(2)O)(2)](ClO(4))(4).4CH(3)OH (), containing the ferrocenyl functionality were prepared via coordination-driven self-assembly and Cl-anion template from Cu(II), Ni(II) and Co(II) salts and a flexible two-arm molecule 1,1-bis[(3-pyridylamino)carbonyl]ferrocene (3-BPFA).