Crystal structure of poly[hexa-µ-bro-mido-bis{2-[1-(py-ri-din-2-yl)ethyl-idene-amino]ethanol-ato}tetracopper(II)].

The reaction of the Schiff base 2-[1-(pyridin-2-yl)ethyl-idene-amino]-ethanol (HL), which is formed by reaction of 2-amino-ethanol and 2-acetyl-pyridine with CuBr2 in ethanol results in the isolation of the new polymeric complex poly[hexa-µ-bromido-bis-{2-[1-(pyridin-2-yl)ethyl-idene-amino]-ethano-lato}tetra-copper(II)], [Cu4Br6(C9H11N2O)2]n or [Cu4Br6 L 2]n. The asymmetric unit of the crystal structure of the polymeric [Cu4Br6 L 2]n complex is composed by four copper (II) cations, two monodeprotonated mol-ecules of the ligand, and six bromide anions, which act as bridges. The ligand mol-ecules act in a tridentate fashion through their azomethine nitro-gen atoms, their pyridine nitro-gen atoms, and their alcoholate O atoms. The crystal structure shows two types of geometries in the coordination polyhedrons around Cu2+ ions. Two copper cations are situated in a square-based pyramidal environment, while the two other copper cations adopt a tetra-hedral geometry. Bromides anions acting as bridges between two metal ions connect the units, resulting in a tetra-nuclear polymer compound.

Synthesis and crystal structures of two related Co and Mn complexes: a celebration of collaboration between the universities of Dakar and Southampton.

We report the synthesis and structures of two transition-metal complexes involving 2-(2-hy-droxy-phen-yl)benzimidazole (2hpbi - a ligand of inter-est for its photoluminescent applications), with cobalt, namely, bis-[µ-2-(1H-1,3-benzo-diazol-2-yl)phenolato]bis-[ethanol(thio-cyanato)-cobalt(II)], [Co2(C13H9N2O)2(NCS)2(C2H6O)2], (1), and manganese, namely, bis-[µ-2-(1H-1,3-benzo-diazol-2-yl)phenolato]bis-{[2-(1H-1,3-benzo-diazol-2-yl)phenolato](thio-cyanato)-mang-an-ese(III)} dihydrate, [Mn2(C13H9N2O)4(NCS)2]·2H2O, (2). These structures are two recent examples of a fruitful collaboration between researchers at the Laboratoire de Chimie de Coordination Organique/Organic Coordination Chemistry Laboratory (LCCO), University of Dakar, Senegal and the National Crystallography Service (NCS), School of Chemistry, University Southampton, UK. This productive partnership was forged through meeting at Pan-African Conferences on Crystallography and quickly grew as the plans for the AfCA (African Crystallographic Association) developed. This article therefore also showcases this productive partnership, in celebration of the IUCr's 75 year anniversary and the recent inclusion of AfCA as a Regional Associate of the IUCr.

Tetra-nuclear copper(II) complex of 2-hydroxy-N,N'-bis-[1-(2-hy-droxy-phen-yl)ethyl-idene]-propane-1,3-di-amine.

The title mol-ecular structure, namely, (µ3-acetato)(µ2-acetato)-bis-(µ3-1,3-bis-{[1-(2-oxidophen-yl)ethyl-idene]amino}-propan-2-olato)tetra-copper(II) monohydrate, [Cu4(C19H19N2O3)2(CH3CO2)2]·H2O, corresponds to a non-symmetric tetra-nuclear copper complex. The complex exhibits one ligand mol-ecule that connects two copper CuII metal centres via its ethano-lato oxygen anion acting in a µ2-mode and one ligand mol-ecule that connects three copper CuII metal centres via its ethano-lato oxygen anion acting in a µ3-mode. One bridging acetate group acting in an η1:η1-µ2-mode connects two copper(II) ions while another bridging acetate group connects three copper(II) ions in an η1:-η2-µ3-mode. A chair-like Cu3O3 structure is generated in which the two CuO4N units are connected by one µ2-O ethano-late oxygen atom. These two units are connected respectively to the CuO3N unit via one µ3-O ethano-late oxygen atom and one µ2-O atom from an acetate group. The µ3-O atom also connects one of the CuO4N units and the CuO3N unit to another CuO3N unit, which is out of the chair-like structure. Each of the two penta-coordinated CuII cations has a distorted NO4 square-pyramidal environment. The geometry of each of the two CuNO3 units is best described as a slightly square-planar environment. A series of intra-molecular O-H⋯O hydrogen bonds is observed. In the crystal, the units are connected by inter-molecular C-H⋯O and O-H⋯O hydrogen bonds, thus forming sheets parallel to the ac plane.

Hexanuclear copper(II) complex of 2-hy-droxy-N,N'-bis-[1-(2-hy-droxy-phen-yl)ethyl-idene]propane-1,3-di-amine incorporating an open-cubane core.

The title mol-ecular structure, namely, di-aqua-tris-(µ3-1,3-bis-{[1-(2-oxidophen-yl)ethyl-idene]amino}-propan-2-olato)-µ3-hydroxido-dinitrato-hexa-copper(II) ethanol tris-olvate, [Cu6(C19H19N2O3)3(NO3)2(OH)(H2O)2]·3C2H5OH, corres-ponds to a non-symmetric hexa-nuclear copper complex. The complex exhibits one core in which three CuII metal centres are mutually inter-connected, two by two, via three phenolato oxygen anions acting in a µ2-mode. These three copper cations are inter-connected in a µ3-mode by one hydroxyl group. An open-cube structure is generated in which each of the CuII cations of the three CuO4N units is connected by two µ2-O anions from phenolate groups and one µ3-O atom from a hy-droxy anion. Each of the three penta-coordinated CuII cations situated in the open-cube unit has a distorted NO4 square-pyramidal environment. Each of these three CuII centres is inter-connected with another CuII cation via one enolate O atom in µ2-mode, yielding one CuNO4 unit and two CuNO3 units. The penta-coordinated CuII atom has a distorted square-pyramidal environment while the two tetra-coordinated copper(II) cations are situated in a square-planar environment. A series of intra-molecular O-H⋯O hydrogen bonds are observed. In the crystal, the units are connected two by two by inter-molecular C-H⋯O and O-H⋯O hydrogen bonds, thus forming sheets parallel to the ac plane.

Crystal structure of N'-[4-(di-methyl-amino)-benzyl-idene]furan-2-carbohydrazide monohydrate.

The condensation of 2-furoic hydrazide and 4-dimethyl amino-benzaldehyde in ethanol yielded a yellow solid formulated as the title compound, C14H15N3O2·H2O. The crystal packing is stabilized by inter-molecular O(water)-H⋯O,N(carbohydrazide) and N-H⋯O(water) hydrogen bonds, which form a two-dimensional network along the bc plane. Additional C-H⋯O inter-actions link the mol-ecules into a three-dimensional network. The dihedral angle between the mean planes of the benzene and the furan ring is 34.47 (6)°. The carbohydrazide moiety, i.e., the C=N-N-C=O fragment and the benzene ring are almost coplanar, with an angle of 6.75 (9)° between their mean planes.

Di-aqua-bis-{µ-1,5-bis-[(pyridin-2-yl)methyl-idene]carbonohydrazide(1-)}di-µ-chlorido-tetra-chlorido-tetra-zinc(II).

A tetra-nuclear ZnII complex, [Zn4(C13H11N6O)2Cl6(H2O)2] or {[Zn2(HL)(H2O)(Cl2)](µCl)2[Zn2(HL)(H2O)(Cl)]}2, was synthesized by mixing an equimolar amount of a methanol solution containing ZnCl2 and a methanol solution containing the ligand H2 L [1,5-bis-(pyridin-2-yl-methyl-ene)carbono-hydrazide]. In the tetra-nuclear complex, each of the two ligand mol-ecules forms a dinuclear unit that is connected to another dinuclear unit by two bridging chloride anions. In each dinuclear unit, one ZnII cation is penta-coordinated in a N2OCl2 in a distorted square-pyramidal geometry, while the other ZnII cation is hexa-coordinated in a N3OCl2 environment with a distorted octa-hedral geometry. The basal plane around the penta-coordinated ZnII cation is formed by one chloride anion, one oxygen atom, one imino nitro-gen atom and one pyridine nitro-gen atom with the apical position occupied by a chloride anion. The basal plane of the hexa-coordinated ZnII cation is formed by one chloride anion, one hydrazinyl nitro-gen atom, one imino nitro-gen atom and one pyridine nitro-gen atom with the apical positions occupied by a water oxygen atom and a bridged chloro anion from another dinuclear unit, leading to a tetra-nuclear complex. A series of intra-molecular C-H⋯Cl hydrogen bonds is observed in each tetra-nuclear unit. In the crystal, the tetra-nuclear units are connected by inter-molecular C-H⋯Cl, C-H⋯O and N-H⋯O hydrogen bonds, forming a planar two-dimensional structure in the ac plane.