A family of double-bowl pseudo metallocalix[6]arene discs

A ferromagnetically coupled pseudo-calixarene [Co16] wheel that self-assembles as a tubular network of capsules

Reaction of Co(OAc)₂·4H₂O and Hsal in a basic MeCN solution affords the hexadecanuclear wheel [Co₁₆(sal)₁₆(OAc)₁₆]·16MeCN (1·16MeCN) that displays ferromagnetic nearest neighbour exchange and has pseudo-calixarene character. Symmetry equivalent wheels self-assemble to form remarkable tubular networks of capsules in the extended structure.

Crystal structure of bis-{μ-2-meth-oxy-6-[(methyl-imino)-meth-yl]phenolato}bis-({2-meth-oxy-6-[(methyl-imino)-meth-yl]phenolato}nickel(II)) involving different coordination modes of the same Schiff base ligand

The structure of the title compound, [Ni2(C9H10NO2)4], is built up by discrete centrosymmetric dimers. Two nitro-gen and three oxygen atoms of two Schiff base ligands singly deprotonated at the phenolate site form a square-pyramidal environment for each metal atom. The ligands are bonded differently to the metal centre: one of the phenolic O atoms is bound to one nickel atom, whereas another bridges the two metal atoms to form the dimer. The Ni-N/O distances fall in the range 1.8965 (13)-1.9926 (15) Å, with the Ni-N bonds being slightly longer; the fifth contact of the metal to the bridging phenolate oxygen atom is substanti-ally elongated [2.533 (1) Å]. A similar coordination geometry was observed in the isomorphous Cu analogue previously reported by us [Sydoruk et al. (2013 ▸). Acta Cryst. E69, m551-m552]. In the crystal, the [Ni2 L 4] mol-ecules form sheets parallel to the ab plane with the polar meth-oxy groups protruding into the inter-sheet space and keeping the sheets apart. Within a sheet, the mol-ecules are stacked relative to each other in such a way that the Ni2O2 planes of neighbouring mol-ecules are orthogonal.

Crowding out: ligand modifications and their structure directing effects on brucite-like {Mx(μ3-OH)y} (M = Co(ii), Ni(ii)) core growth within polymetallic cages

Previous employment of the ligands 2-methoxy-6-[(methylimino)methyl]phenol (L₁H) and 2-methoxy-6-[(phenylimino)methyl]phenol (L₂H) has resulted in the self-assembly of pseudo metallocalix[6]arene complexes of general formulae: [M₇(μ₃-OH)₆(L_x)₆](NO₃)_y (M = Ni(ii), x = 1, y = 2 (1) and Co(ii/iii), x = 2, y = 3 (2)). Extrapolating upon this work, we report the coordination chemistry of ligands 2-methoxy-6-{[(2-methoxyphenyl)imino]methyl}phenol (L₃H), 2-[(benzylimino)methyl]-6-methoxyphenol (L₄H), 2-[(benzylamino)methyl]-6-methoxyphenol (L₅H) and 2-[(benzylamino)methyl]-4-bromo-6-methoxyphenol (L₆H), whose structures are modifications of ligands L_1-2H. These ligands are employed in the synthesis and characterisation of the dimetallic complex [Ni(ii)₂(L₃)₃(H₂O)](NO₃)·2H₂O·3MeOH (3); the monometallic complexes [Ni(ii)(L₄)₂] (4) and [Co(iii)(L₄)₃]·H₂O·MeOH (5a); and the tetranuclear pseudo metallocalix[4]arene complexes: [(NO₃)⊂Co(ii)₄(μ₃-OH)₂(L₅)₄(H₂O)₂](NO₃)·H₂O (6), [(NO₃)⊂Ni(ii)₄(μ₃-OH)₂(L₅)₄(H₂O)₂](NO₃)·H₂O (7) and [Ni(ii)₄(μ₃-OH)₂(L₆)₄(NO₃)₂]·MeCN (8). The tetrametallic 'butterfly' core topologies in 6-8 are discussed with respect to their structural and topological relationship with their heptanuclear [M₇] (M = Co(ii), Ni(ii)) pseudo metallocalix[6]arene ancestors (1 and 2).

Variation of nuclearity in NiII complexes of a Schiff base ligand: crystal structures and magnetic studies

Four Ni^II complexes have been synthesized by changing the reaction conditions and stoichiometry of the reactants. The magnetic coupling in the NiII4 complex is ferromagnetic whereas that in the NiII6 complex is antiferromagnetic.

Crystal structure of 4,10-dimeth-oxy-13-methyl-6H,12H-6,12-epimino-dibenzo[b,f][1,5]dioxocine

The title compound, C17H17NO4, lacks crystallographic symmetry with one mol-ecule per asymmetric unit. The mol-ecule exists in a folded butterfly-like conformation; the benzene rings form a dihedral angle of 84.72 (7)°. The central eight-membered imino-bridged dioxocin ring adopts a twisted-boat conformation. In the crystal, inversion-related mol-ecules are linked by pairs of weak C-H⋯O hydrogen bonds, forming double-stranded chains parallel to the a axis.

An octanuclear Schiff-base complex with a Na2Ni6 core: structure, magnetism and DFT calculations

An octanuclear complex with a Na₂Ni₆ core was prepared and characterized. Its magnetic properties were thoroughly studied by experimental and theoretical methods.

Competing ferro- and antiferromagnetic interactions in a hexagonal bipyramidal nickel thiolate cluster

A new hexagonal bipyramidal Ni8 cluster is reported and its magnetic behaviour is analyzed. The molecular structure consists of a hexagonal wheel capped by two additional apical Ni(2+) ions. This structure supports ferromagnetic superexchange interactions between adjacent Ni(2+) ions in the wheel and an antiferromagnetic superexchange interaction between the wheel and apical Ni(2+) ions.

Microwave-assisted synthesis, structure and property of a spin-glass heptanuclear nickel cluster with 2-iminomethyl-6-methoxy-phenol

A new heptanuclear nickel cluster [Ni7(immp)6(OMe)6]·(ClO4)2 (1, Himmp is 2-iminomethyl-6-methoxy-phenol) has been synthesized through the microwave-assisted reaction of Ni(ClO4)2·6H2O with 2-hydroxy-3-methoxy-benzaldehyde and ammonium water in mixed solvent (acetonitrile: methanol = 1:1). Complex 1 was characterized by IR spectroscopy, elemental analysis and X-ray single-crystal diffraction. Magnetic property of 1 indicates the relaxation time τ 0 = 1.28 × 10–15 s and the energy barrier U eff / k B = 70.4 K, which is a spin glass.

Molecular Pac-Man and Tacos: layered Cu(ii) cages from ligands with high binding site concentrations

Sheet Metal: The deliberate in situ Schiff base condensation of two organic subunits (hydroxamic acid and phenolic aldehyde) leads to polydentate ligands capable of forming large Cu(ii) cages of nuclearities ranging from [Cu₁₀] to [Cu₃₀].

Structural variation from heterometallic heptanuclear or heptanuclear to cubane clusters based on 2-hydroxy-3-ethoxy-benzaldehyde: effects of pH and temperature

Five novel clusters were reported, with results showing that pH and reaction temperatures have a key role in the self-assembly process.

Bis{μ-2-meth-oxy-6-[(methyl-imino)-meth-yl]phenolato}bis-({2-meth-oxy-6-[(methyl-imino)-meth-yl]phenolato}copper(II))

The title compound, [Cu₂(C₉H₁₀NO₂)₄], is built of discrete centrosymmetric dimers. The Cu^II atoms are each five coordinated by two deprotonated Schiff base ligands that are bonded differently to the metal atoms. Of the two phenolate O atoms, one is coordinated to one Cu^II atom, whereas another bridges the two metal atoms. The basal plane of the square pyramid around Cu^II atoms is formed by the imino N and phenolate O atoms of the bidentate and the monodentate/bidentate Schiff base ligands. The bridging phenolate oxygen occupies the apical position of the coordination sphere with a considerably longer Cu—O bond length. In the crystal, the dimeric mol­ecules pack relative to each other in such a way that the Cu₂O₂ planes of adjacent dimers are orthogonal.