Crystal structure of poly[(aceto-nitrile-κN)(µ3-7-{[bis-(pyridin-2-ylmeth-yl)amino]-meth-yl}-8-hy-droxy-quinoline-5-sulfonato-κ4N,O:O':O'')sodium].

In the title compound, [Na(C22H19N4O4S)(CH3CN)]n, the NaI atom adopts a distorted square-pyramidal coordination geometry, formed by one N and one O atom of the qunolinol moiety in the ligand, two O atoms of sulfonate moieties of two adjacent ligands and the N atom of the coordinated aceto-nitrile solvent. The NaI atom is located well above the mean basal plane of the square-based pyramid. The apical position is occupied by a sulfonate O atom of a neighboring ligand. Three N atoms of the bis-(pyridin-2-ylmeth-yl)amine moiety in the ligand are not coordinated by the sodium atom. The mol-ecule forms an intra-molecular bifurcated O-H⋯[N(tertiary amine),N(pyridine)] hydrogen bond, generating S(6) and S(5) rings. In the crystal, four mol-ecules are linked by four Na-O(sulfonato) bridged coordination bonds, forming a supra-molecular centrosymmetric tetra-mer unit comprising an eight-membered ring, and generating a two-dimensional network sheet. The mol-ecules of different sheets form inter-molecular C-H⋯O hydrogen bonds, and thereby a three-dimensional network structure.

Crystal structure of (7-{[bis-(pyridin-2-ylmeth-yl)amino-κ3 N,N',N'']meth-yl}-5-chloro-quinolin-8-ol)di-bromidozinc(II).

In the title compound, [ZnBr2(C22H19ClN4O)], the ZnII atom adopts a distorted square-pyramidal coordination geometry, formed by two bromido ligands and three N atoms of the bis-(pyridin-2-ylmeth-yl)amine moiety in the penta-dentate ligand containing quinolinol. The ZnII atom is located well above the mean basal plane of the square-based pyramid. The apical position is occupied by a Br atom. The O and N atoms of the quinolinol moiety in the ligand are not coordinated to the ZnII atom. An intra-molecular O-H⋯N hydrogen bond, generating an S(5) ring motif, stabilizes the mol-ecular structure. In the crystal, the mol-ecules are linked by inter-molecular C-H⋯Br hydrogen bonds, generating ribbon structures containing alternating R 2 2(22) and R 2 2(14) rings. These ribbons are linked through an inter-molecular C-H⋯Br hydrogen bond, forming a two-dimensional network sheet.

Crystal structure of 7-hy-droxy-8-[(4-methyl-piperazin-1-yl)meth-yl]-2H-chromen-2-one.

In the title compound, C15H18N2O3, the coumarin ring is essentially planar, with an r.m.s. deviation of 0.012 Å. An intra-molecular O-H⋯N hydrogen bond forms an S(6) ring motif. The piperazine ring adopts a chair conformation. In the crystal, a C-H⋯O hydrogen bond generates a C(4) chain motif running along the c axis. The chain structure is stabilized by a C-H⋯π inter-action. The chains are linked by π-π inter-actions [centroid-centroid distance of 3.5745 (11) Å], forming a sheet structure parallel to the bc plane.

Crystal structure of 7-{[bis-(pyridin-2-ylmeth-yl)amino]-meth-yl}-5-chloro-quinolin-8-ol.

In the title compound, C22H19ClN4O, the quinolinol moiety is almost planar [r.m.s. deviation = 0.012 Å]. There is an intra-molecular O-H⋯N hydrogen bond involving the hy-droxy group and a pyridine N atom forming an S(9) ring motif. The dihedral angles between the planes of the quinolinol moiety and the pyridine rings are 44.15 (9) and 36.85 (9)°. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds forming inversion dimers with an R 4 (4)(10) ring motif. The dimers are linked by C-H⋯N hydrogen bonds, forming ribbons along [01-1]. The ribbons are linked by C-H⋯π and π-π inter-actions [inter-centroid distance = 3.7109 (11) Å], forming layers parallel to (01-1).

Di-µ 2-acetato-1:2κ (2) O:O';2:3κ (2) O:O'-bis-{µ 2-4,4'-di-chloro-2,2'-[2,2-di-methyl-propane-1,3-diylbis(nitrilo-methanylyl-idene)]diphenolato}-1:2κ (6) O,N,N',O':O,O';2:3κ (6) O,O':O,N,N',O'-tri-cadmium.

In the title linear homo-trinuclear complex, [Cd3(C19H18Cl2N2O2)2(C2H3O2)2], the central Cd(II) atom is located on a centre of inversion and has a distorted octa-hedral coordination geometry formed by four O atoms from two bidentate/tetra-dentate Schiff base ligands and two O atoms from two bridging acetate ligands. The coordination geometry of the terminal Cd(II) atom is square-pyramidal with the tetra-dentate part of the ligand in the basal plane and one O atom from an acetate ligand occupying the apical site. The six-membered CdN2C3 ring adopts a chair conformation. The acetate-bridged Cd⋯Cd distance is 3.3071 (2) Å. The crystal structure is stabilized by C-H⋯O hydrogen bonds, which form C(7) chain motifs and give rise to a two-dimensional supra-molecular network structure lying parallel to the ab plane.

Di-µ(2)-acetato-1:2κ(2)O:O';2:3κ(2)O:O'-bis-{µ(2)-4,4'-dichloro-2,2'-[2,2-dimethyl-propane-1,3-diylbis(nitrilo-methanylyl-idene)]diphenolato}-1:2κ(6)O,N,N',O':O,O';2:3κ(6)O,O':O,N,N',O'-tricopper(II).

The title compound, [Cu(3)(C(19)H(18)Cl(2)N(2)O(2))(2)(CH(3)CO(2))(2)], is a linear homo-trinuclear Cu(II) complex. The central Cu(II) atom is located on a centre of inversion and has a distorted octa-hedral coordination environment formed by six O atoms from two tetra-dentate Schiff base ligands and two bridging acetate ligands. The coordination geometry of the terminal Cu(II) atom is square-pyramidal with a tetra-dentate ligand in the basal plane. The apical site is occupied by one O atom from an acetate ligand. The acetate-bridged Cu⋯Cu distance is 3.0910 (5) Å. An intra-molecular C-H⋯O hydrogen bond forms an S(6) ring motif. The crystal of the trinuclear complex is stabilized by C-H⋯O hydrogen bonds.

Aqua-{4,4',6,6'-tetra-fluoro-2,2'-[(piperazine-1,4-di-yl)dimethyl-ene]diphenolato}copper(II).

In the title compound, [Cu(C(18)H(16)F(4)N(2)O(2))(H(2)O)], the Cu(II) atom shows a distorted square-pyramidal coordination geometry with the N,N',O,O'-tetra-dentate piperazine-diphenolate ligand forming the basal plane. The apical site is occupied by the O atom of a coordinated water mol-ecule. Neighbouring complexes are associated through inter-molecular O-H⋯O and O-H⋯F hydrogen bonds between the water mol-ecule and a phenolate O atom or an F atom from an adjacent ligand, respectively, forming a centrosymmetric dimer. Dimers are linked by additional inter-molecular C-H⋯O and C-H⋯F hydrogen bonds, giving infinite chains propagating along the a axis.

Bis[µ-4,4',6,6'-tetra-chloro-2,2'-(piperazine-1,4-diyldimethyl-ene)diphenolato]dicopper(II).

In the centrosymmetric dinuclear Cu(II) title complex, [Cu(2)(C(18)H(16)Cl(4)N(2)O(2))(2)], the Cu(II) atom adopts a square-pyramidal geometry with a tetra-dentate ligand in the basal plane. The apical site is occupied by a phenolate O atom from an adjacent ligand, forming a dimer. The mol-ecular structure is stabilized by intra-molecular C-H⋯O and C-H⋯Cl hydrogen bonds.

4,4'-Dichloro-2,2'-(piperazine-1,4-diyldimethyl-ene)diphenol.

In the titile compound, C(18)H(20)Cl(2)N(2)O(2), the piperazine ring adopts a chair conformation. The mol-ecule has a non-crystallographic inversion centre in the middle of the piperazine ring at approximate position (3/4, 1/8, 3/8). There are intra-molecular O-H⋯N hydrogen bonds forming S(6) ring motifs. Inter-molecular C-H⋯O hydrogen bonds generate anti-parallel C(5) chain motifs propagating along the b axis, forming sheets parallel to the bc plane with a first-level graph-set S(6)C(5)R(6) (6)(26).

A monoclinic polymorph of 4,4'-dichloro-2,2'-(piperazine-1,4-diyl-dimethyl-ene)diphenol.

The titile compound, C(18)H(20)Cl(2)N(2)O(2), crystallizes as a monoclinic form in the space group P2(1)/n, with Z' = 1/2. It is polymorphic with the previously reported orthorhombic form [Kubono, Tsuno, Tani & Yokoi (2008). Acta Cryst. E64, o2309]. In the present polymorph, the mol-ecule lies on a crystallographic inversion centre at the piperazine ring centroid. An intra-molecular O-H⋯N hydrogen bond forms an S(6) ring motif. Inter-molecular C-H⋯O hydrogen bonding generates a C(5) chain motif propagating along the b axis, forming sheets parallel to (02) with a first-level graph set S(6)C(5)R(6) (6)(34).

Monoclinic and orthorhombic polymorphs of 4,4',6,6'-tetrachloro-2,2'-(piperazine-1,4-diyldimethylene)diphenol.

The title compound, C(18)H(18)Cl(4)N(2)O(2), crystallizes as monoclinic and orthorhombic polymorphs from CHCl3-CH(3)OH solution. In both polymorphic forms, the molecule lies on a crystallographic centre of inversion (at the piperazine ring centroid) and exhibits an intramolecular O-H...N hydrogen bond. In the monoclinic polymorph (space group P2(1)/c), the molecules are linked by intermolecular C-H...Cl hydrogen bonds into a ribbon sheet built from R8(8)(34) rings. In the orthorhombic polymorph (space group Pbcn), the molecules are linked by intermolecular C-H...O hydrogen bonds into a ribbon sheet of R6(6)(34) rings. The sheets in the orthorhombic polymorph are crosslinked into a three-dimensional framework by pi-pi stacking interactions.

Dissolved iron and its speciation in a shallow eutrophic lake and its inflowing rivers.

It has been suggested that iron is a limiting factor on bloom-forming cyanobacteria in lake water. Although the availability of iron for phytoplankton depends significantly on its speciation, little is known about iron speciation in natural lake water. We investigated the horizontal distribution and temporal variation of dissolved iron and its chemical speciation in Lake Kasumigaura and its two inflowing rivers. Concentrations of dissolved iron and its organic ligands, determined by cathodic stripping voltammetry, clearly decreased as lake water flowed from the river entry points toward the center of the lake, indicating their riverine origin. The fraction of iron occurring in organic complexes tended to increase with the water flow. These results suggest that most of the dissolved iron in river water forms unstable soluble species, such as inorganic iron; thus, these unstable iron species may be scavenged in the mouths of rivers, and stable organic complexes of iron may flow to the center of the lake. Furthermore, most of the dissolved iron (88.2-99.9%) was present as organic complexes, and the inorganic iron level in Lake Kasumigaura (pFe' value=7.8-13.6) was similar to that observed in the open ocean. This result suggests that iron is an important factor determining the structure of the phytoplankton community in Lake Kasumigaura.

Crystal structure of [1,4-bis[1-(3,5-dichlorophenolato-2-ylmethyl)-ylpropylamino-kappa2N,O]piperazine-kappa2N,N']cobalt(II).

The X-ray crystal structure of the title complex, Co(Cl2bprpi) is described. In this complex the Co(II) center displays a distorted octahedral coordination geometry. The piperazine ring exhibits boat conformation, forming chelate rings and capping the Co atom. The N2-Col-N3 angle is 69.41(15) degrees, extremely smaller than 90 degrees. Because the small angle causes a large steric hindrance, the piperazine ring can be effective as an ion size-recognition site. The molecular structure is stabilized by intramolecular N-H...O hydrogen bonds and Cl...H contacts.