Poly[[(1,10-phenanthroline)(µ-l-tartrato)zinc] hexa-hydrate].

The title compouand {[Zn(C(4)H(4)O(6))(C(12)H(8)N(2))]·6H(2)O}(n), has a linear chain structure parallel to [100] with Zn(C(4)H(4)O(6))(C(12)H(8)N(2)) repeat units; the asymmetric unit consists of one Zn(2+) cation, one l-tartrate dianion, one 1,10-phenanthroline and six free water mol-ecules. The Zn atom is in a distorted octa-hedral ZnN(2)O(4) coordination environment. The crystal structure is stabilized by O-H⋯O hydrogen bonds and π-π stacking of the phenanthroline units [centroid-centroid distances in the range 3.552 (2)-3.625 (2)Å] occurs between the chains. The title compound is isotypic with the Cu and Mn analogues.

Bis(2-propyl-1H-imidazol-3-ium) bis-(pyridine-2,6-dicarboxyl-ato-κO,N,O)cadmate(II).

The title salt, (C(6)H(11)N(2))(2)[Cd(C(7)H(3)NO(4))(2)], displays a discrete mononuclear structure, in which the central Cd(II) atom is six-coordinated in a distorted octa-hedral coordination geometry by two N and four O atoms from two different pyridine-2,6-dicarboxyl-ate anions in an O(2),N,O(6)-tridentate chelation mode. The crystal packing is stabilized by N-H⋯O hydrogen bonds and π-π inter-actions [centroid-centroid distance = 3.576 (5) Å].

[µ-1,4-Bis(1,2,4-triazol-1-ylmeth-yl)benzene]-bis-[aqua-(pyridine-2,6-dicarboxyl-ato)copper(II)] monohydrate.

The title compound, [Cu(2)(C(7)H(3)NO(4))(2)(C(12)H(12)N(6))(H(2)O)(2)]·H(2)O, displays a discrete dinuclear structure, in which the central Cu(II) atom is five-coordinated in a distorted square-based pyramidal coordination geometry and the flexible ligand 1,4-bis-(1,2,4-triazol-1-ylmeth-yl)benzene adopts a bis-monodentate bridging mode linking the Cu(II) atoms. It is further assembled by O-H⋯O hydrogen-bond inter-actions involving both the coordinated and uncoordinated water molecules. The latter exhibits half-occupancy.

Hexa-kis-(1-benzyl-1H-imidazole-κN)manganese(II) bis-(perchlorate).

In the title compound, [Mn(C(10)H(10)N(2))(6)](ClO(4))(2), the Mn(II) ion, located on an inversion center, is coordinated by six N atoms from three pairs of symmetry-related 1-benzyl-1H-imidazole ligands in a distorted octa-hedral geometry. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link the complex cations and perchlorate anions.

1,4-Bis[(1H-pyrazol-1-yl)meth-yl]benzene.

In the title compound, C(14)H(14)N(4), the center of the phenyl-ene group is a crystallographic center of inversion. The compound is composed of three aromatic rings displaying a Z-like conformation. The dihedral angle between the pyrazole rings and the central phenyl ring is 83.84 (9)°.

1,1'-[1,4-Phenyl-enebis(methyl-ene)]bis-(2-methyl-1H-imidazol-3-ium) 2,4-dicarb-oxy-benzene-1,5-dicarboxyl-ate monohydrate.

In the dication of the title compound, C(16)H(20)N(4) (2+)·C(10)H(4)O(8) (2-)·H(2)O, the dihedral angles formed by mean planes of the imidazolium rings and the benzene ring are 69.05 (18) and 89.1 (2)°. In the crystal, the components are linked into a three-dimensional network by inter-molecular N-H⋯O and O-H⋯O hydrogen bonds.

1,4-Bis(1H-benzimidazol-1-yl)but-2-ene.

In the pseudo-centrosymmetric mol-ecule of the title compound, C(18)H(16)N(4), two benzimidazole fragments form the dihedral angles of 83.49 (7) and 79.37 (7)°, with the mean plane of the linking butene chain. No classical inter-molecular inter-actions are observed. The porous crystal packing exhibits voids of 85 Å(3).

[Cultivation and isolation of bacteria coupling nitrogen removal from wastewater and hydrogen sulfide removal from biogas].

It was studied that during the startup of reactors the crucial bacteria coupling nitrogen removal from swine wastewater and hydrogen sulfide removal from biogas using bubbling absorption reactors without seeding sludge, with seeding anaerobic sludge and aerobic sludge, respectively. During the prophase of the experiment (before the 26th d), the removal rate of nitrogen and hydrogen sulfide were from 50% to 64% in reactors with seeding sludge, that in the reactor without seeding sludge was only 11%-14%. At the end of experiment (the 56th d after startup), the removal rates of nitrogen for three reactors were about 90%. The removal rates of hydrogen sulfide were more than 70%. The result showed that though the finishing time for startup of the reactor without seeding sludge was longer than that with seeding sludge, it could be obtained the same effect of removal of nitrogen and hydrogen sulfide as the latter after two months cultivation. In the different period of startup of the reactors, the variation of the population of bacteria was studied, which had the same trend as the removal effect of nitrogen and hydrogen sulfide. Two strains which could remove the nitrogen and hydrogen sulfide more than 60% simultaneously were isolated from the three reactors, and primarily identified as Thiobacillus denitrificans and Pseudomonas respectively, based on their morphology and physiological characters.