The selective monobromination of a highly sterically encumbered corrole: Structural and spectroscopic properties of Fe(Cl)(2-bromo-5,10,15-tris(triphenyl)phenyl corrole)

The corrole ligand serves as a versatile tri-anionic, macrocyclic platform on which to model biological catalytic systems, as well as to effect mechanistically challenging chemical transformations. Herein we describe the synthesis, structure, and characterization of an isomerically pure corrole ligand, selectively mono-brominated at the β-carbon position adjacent to the corrole C-C bond (2-C) and produced in relatively high yields, as well as its iron chloride complex. Analysis of the iron metalated complex by cyclic voltammetry shows that the bromine being present on the ligand resulted in anodic shifts of +93 and +63 mV for first oxidation and first reduction of the complex respectively. The Mössbauer spectrum of the iron metalated complex shows negligible change relative to the non-brominated analog, indicating the presence of the halide substituent predominantly effects the orbitals of the ligand rather than the metal.

Importance of anions in electrodeposition of nickel from gluconate solutions

Electrodeposition of nickel from slightly acidic gluconate solutions containing chloride or/and sulfate ions was investigated. Electrochemical measurements correlated with bath speciations showed nickel chloride complex and nickel sulfate complexes as crucial species affecting cathodic reactions in a potential range up to −1.3V. At more negative potentials, nickel deposition was governed by a release of nickel cation from nickel-gluconate complex. This was further evidenced by differences in nucleation modes, morphology, and structure of the deposits. Wettability of as-plated and chemically modified nickel layers were determined and correlated with their morphology and corrosion resistance.

Molecular and Crystal Structure of a Chitosan−Zinc Chloride Complex

We determined the molecular and packing structure of a chitosan–ZnCl2 complex by X-ray diffraction and linked-atom least-squares. Eight D-glucosamine residues—composed of four chitosan chains with two-fold helical symmetry, and four ZnCl2 molecules—were packed in a rectangular unit cell with dimensions a = 1.1677 nm, b = 1.7991 nm, and c = 1.0307 nm (where c is the fiber axis). We performed exhaustive structure searches by examining all of the possible chain packing modes. We also comprehensively searched the positions and spatial orientations of the ZnCl2 molecules. Chitosan chains of antiparallel polarity formed zigzag-shaped chain sheets, where N2···O6, N2···N2, and O6···O6 intermolecular hydrogen bonds connected the neighboring chains. We further refined the packing positions of the ZnCl2 molecules by theoretical calculations of the crystal models, which suggested a possible coordination scheme of Zn(II) with an O6 atom.

Synthesis and structure of a complex of copper(I) with L-cysteine and chloride ions containing Cu12S6 nanoclusters

The title hydrated copper(I)–L-cysteine–chloride complex has a polymeric structure of composition {[Cu16(CysH2)6Cl16]·xH2O} n [CysH2 = HO2CCH(NH3 +)CH2S− or C3H7NO2S], namely, poly[[tetra-μ3-chlorido-deca-μ2-chlorido-dichloridohexakis(μ4-L-cysteinato)hexadecacopper] polyhydrate]. The copper atoms are linked by thiolate groups to form Cu12S6 nanoclusters that take the form of a tetrakis cuboctahedron, made up of a Cu12 cubo-octahedral subunit that is augmented by six sulfur atoms that are located symmetrically atop of each of the Cu4 square units of the Cu12 cubo-octahedron. The six S atoms thus form an octahedral subunit themselves. The exterior of the Cu12S6 sphere is decorated by chloride ions and trichlorocuprate units. Three chloride ions are coordinated in an irregular fashion to trigonal Cu3 subunits of the nanocluster, and four trigonal CuCl3 units are bonded via each of their chloride ions to a copper ion on the Cu12S6 sphere. The trigonal CuCl3 units are linked via Cu2Cl2 bridges covalently connected to equivalent units in neighboring nanoclusters. Four such connections are arranged in a tetrahedral fashion, thus creating an infinite diamond-like net of Cu12S6Cl4(CuCl3)4 nanoclusters. The network thus formed results in large channels occupied by solvent molecules that are mostly too ill-defined to model. The content of the voids, believed to be water molecules, was accounted for via reverse Fourier-transform methods using the SQUEEZE algorithm [Spek (2015). Acta Cryst. C71, 9–18]. The protonated amino groups of the cysteine ligands are directed away from the sphere, forming N—H...Cl hydrogen bonds with chloride-ion acceptors of their cluster. The protonated carboxy groups point outwards and presumably form O—H...O hydrogen bonds with the unresolved water molecules of the solvent channels. Disorder is observed in one of the two crystallographically unique [Cu16(CysH2)6Cl16] segments for three of the six cysteine anions.