Assessment of heavy metal pollution in urban and peri-urban soil of Setif city (High Plains, eastern Algeria).

Heavy metal pollution is a challenging concern that threatens the soil environment and human health worldwide. The purpose of this work is to assess the heavy metals (Cr, Cu, Zn, and Pb) pollution in the urban and peri-urban soils in and around Setif city, eastern Algeria. The work combines chemical analysis of thirty-six soil samples, statistical valuation and interpretation of chemical data and pollution indices (geoaccumulation index, pollution index, and integrated pollution index) with thematic mapping. The average concentrations (in mg/kg) of Cd, Cr, Cu, Pb, and Zn were found < 0.02, 43.35, 43.75, 331.20, and 78.26 mg/kg, respectively. Compared with the French regulatory limits (AFNOR U44-041), Cd, Cr, and Cu still non-hazardous at Setif city scale; however, Zn and Pb concentrations are two to three times higher than the background values referred to the Chinese [Formula: see text] standard (GB15618-1995). The pollution indices indicate that Pb and Zn represent the highest threats among the studied pollutants and polluted wide areas of anthropogenic activities located respectively in the oldest district of the city, near the industrial zone and near uncontrolled landfill of domestic and industrial waste. Cu, Pb, and Zn originate seemly from vehicle emission, particles of brakes and tires, and industrial emissions. However, Cr distribution is uncorrelatable with anthropogenic sources. The Cr with an average concentration less than the background value derives seemly from animal feces and organic fertilizers. The integrated pollution index shows that the accumulation of heavy metals in the soils of Setif city from anthropogenic sources reached alarming levels that can disperse into the environment and threaten the human health. The urbanization and industrial development of Setif city are expected to grow and a subsequent heavy metal pollution will be rising prior issue. Corrective measures should be endeavored by the local authorities to mitigate the current environmental situation and a sustainable development plan for the city should be anticipated to guarantee optimal future environmental conditions.

A strongly fluorescent NiII complex with 2-(2-hy-droxy-eth-yl)pyridine ligands: synthesis, characterization and theoretical analysis and comparison with a related polymeric CuII complex.

The synthesis and characterization of di-aqua-bis-[2-(2-hy-droxy-eth-yl)pyridine-κ2N,O)nickel(II) dinitrate, [Ni(C7H9NO)2(H2O)2](NO3)2, under ambient conditions is reported and compared with catena-poly[[bis-[2-(2-hy-droxy-eth-yl)pyridine-κ2N,O]copper(II)]-µ-sulfato-κ2O:O'], [Cu(C7H9NO)2(SO4)] n [Zegh-ouan et al. (2016 ▸). Private communication (refcode 1481676). CCDC, Cambridge, England]. In the two complexes, the 2-(2-hy-droxy-eth-yl)pyridine ligands coordinate the metal ions through the N atom of the pyridine ring and the O atom of the hy-droxy group, creating a chelate ring. The NiII or CuII ion lies on an inversion centre and exhibits a slightly distorted MO4N2 octa-hedral coordination geometry, build up by O and N atoms from two 2-(2-hy-droxy-eth-yl)pyridine ligands and two water mol-ecules or two O atoms belonging to sulfate anions. The sulfate anion bridges the CuII ions, forming a polymeric chain. The photoluminescence properties of these complexes have been studied on as-synthesized samples and reveal that both compounds display a strong blue-light emission with maxima around 497 nm. From DFT/TDDFT studies, the blue emission appears to be derived from the ligand-to-metal charge-transfer (LMCT) excited state. In addition, the IR spectroscopic properties and thermogravimetric behaviours of both complexes have been investigated.

Crystal structure, thermal and fluorescence properties of 2,2':6',2''-terpyridine-1,1',1''-triium tetra-chlorido-nickelate(II) chloride.

The title compound, (C15H14N3)[NiCl4]Cl, comprises an NiII cation tetra-hedrally coordinated by four chloride anions, a non-coordinating chloride anion and an essentially planar terpyridinium trication (tpyH33+), in which the central pyridinium ring forms dihedral angles of 5.7 (2) and 6.0 (2)° with the peripheral pyridinium rings. Three inter-species N-H⋯Cl hydrogen bonds are formed with the Cl- anion, which also forms a link between the (tpyH33+) cations through an aromatic C-H⋯Cl inter-action, forming a zigzag chain extending along the 21 (b) screw axis. Two of the anionic Cl atoms of the [NiCl4]2- anions form Ni-Cl⋯π inter-actions with separate pyridinium rings [Ni⋯Cg = 3.669 (3) and 3.916 (4) Å]. In the crystal, successive undulating inorganic and organic layers are formed, extending across the (100) plane. Thermogravimetric and differential thermal analysis (TGA/DTA) indicate that the compound starts to decompose at 313 K and may be a candidate for use as a blue-light luminescent material.

Di-aqua-bis-[2-(2-hy-droxy-eth-yl)pyridine-κ(2) N,O]cobalt(II) dichloride.

In the title salt, [Co(C7H9NO)2(H2O)2]Cl2, the Co(II) cation, located on an inversion center, is N,O-chelated by two hy-droxy-ethyl-pyridine ligands and coordinated by two water mol-ecules in a distorted O4N2 octa-hedral geometry. In the crystal, the Cl(-) anions link with the complex cations via O-H⋯Cl hydrogen bonds, forming a three-dimensional supra-molecular architecture. π-π stacking is observed between the pyridine rings of adjacent mol-ecules [centroid-centroid distance = 3.5810 (11) Å].

4-(Di-methyl-amino)-pyridinium trichlorido[4-(di-methyl-amino)-pyridine-κN]cobaltate(II).

In the anion of the title compound, (C7H11N2)[CoCl3(C7H10N2)], the Co(II) ion is coordinated by one N atom from a 4-(di-methyl-amino)-pyridine (DMAP) ligand and three Cl atoms, forming a CoNCl3 polyhedron with a distorted tetra-hedral geometry. In the crystal, cations and anions are linked via weak N-H⋯Cl and C-H⋯Cl hydrogen bonds. Double layers of complex anions stack along the b- axis direction, which alternate with double layers of 4-(di-methyl-amino)-pyridinium cations.

Bis(azido-κN)bis-[4-(dimethyl-amino)-pyridine-κN]zinc.

In the title complex, [Zn(N3)2(C7H10N2)2], the Zn(II) atom is coordinated by two N atoms from two 4-(dimethyl-amino)-pyridine (DMAP) ligands and by two N atoms from two azide anions in a distorted tetra-hedral coordination geometry. In the crystal, weak C-H⋯N hydrogen bonds between the DMAP and azide ligands link these discrete complex mol-ecules into a three-dimensional supra-molecular network.

catena-Poly[[bis-[4-(dimethyl-amino)-pyridine-κN (1)]cobalt(II)]-di-µ-azido-κ(4) N (1):N (3)].

The title layered polymer, [Co(N3)2(C7H10N2)2] n , contains Co(II), azide and 4-(dimethyl-amino)-pyridine (4-DMAP) species with site symmetries m2m, 2 and m, respectively. The Co(2+) ion adopts an octa-hedral coordination geometry in which four N atoms from azide ligands lie in the equatorial plane and two 4-DMAP N atoms occupy the axial positions. The Co(II) atoms are connected by two bridging azide ligands, resulting in a chain parallel to the c axis.

l-Leucinium fluoride monohydrate.

The asymmetric unit of the title hydrated salt, C(6)H(14)NO(2) (+)·F(-)·H(2)O, contains a discrete cation with a protonated amino group, a halide anion and one water mol-ecule. The crystal structure is composed of double layers parallel to (010) held together by N-H⋯O, N-H⋯F, O-H⋯F and C-H⋯F hydrogen bonds, forming a two-dimensional network, and stacked along the c axis, viz. hydro-philic layers at z = 0 and 1/2 and hydro-phobic layers at z = 1/3 and 2/3.

Bis[4-(dimethyl-amino)-pyridinium] octa-aqua-chloridolanthanum(III) tetra-chloride trihydrate.

The title organic-inorganic salt, (C(7)H(11)N(2))(2)[LaCl(H(2)O)(8)]Cl(4)·3H(2)O, consists of two 4-(dimethyl-amino)-pyridinium and one [La(H(2)O)(8)Cl](2+) cations, four chloride anions and three solvent water mol-ecules. In the crystal, the various units are connected by N-H⋯Cl, O-H⋯Cl, O-H⋯O and N-H⋯O hydrogen bonds, forming a network of alternating organic and inorganic layers. The 4-(dimethyl-amino)-pyridinium cations stack along the c axis, while the inorganic layers lie parallel to the ac plane. The chloride anions are located between these entities, forming hydrogen bonds with the NH atom of the pyridinium ions and the water mol-ecules. There are also C-H⋯Cl hydrogen bonds present involving one of the 4-(dimethyl-amino)-pyridinium cations, resulting in the formation of a three-dimensional supra-molecular architecture.

Tris[4-(dimethyl-amino)-pyridinium][(bis-µ-dichlorido)-deca-aqua-dichlorido-dineodymium(III)] penta-chloride dihydrate.

The title compound, (C(7)H(11)N(2))(3)[Nd(2)Cl(4)(H(2)O)(10)]Cl(5)·2H(2)O, consists of three 4-(dimethyl-amino)-pyridinium cations, one of which is disordered about an inversion center, one [Nd(2)Cl(4)(H(2)O)(10)](2+) dication possessing inversion symmetry, five chloride anions, one of which is disordered over two inversion centers, and two lattice water mol-ecules. The 4-(dimethyl-amino)-pyridinium cations are protonated at the pyridine N atoms and form N-H⋯Cl hydrogen bonds with Cl(-) counter-ions. The dimethyl-amino groups (C/N/C) lie close to the plane of the pyridinium rings, making dihedral angles of 1.6 (6)° and 6.5 (3)°. In the crystal, the [Nd(2)Cl(4)(H(2)O)(10)](2+) dications are linked via O-H⋯O and O-H⋯Cl hydrogen bonds, forming sheets lying parallel to the bc plane. These sheets are linked via O-H⋯Cl hydrogen bonds, forming a three-dimensional network. The 4-(dimethyl-amino)-pyridinium cations are located in the cavities and linked to the framework by C-H⋯Cl interactions.

4-(Dimethyl-amino)-pyridinium octa-aqua-erbium(III) tetra-chloride monohydrate.

In the title compound, (C(7)H(11)N(2))[Er(H(2)O)(8)]Cl(4)·H(2)O, the asymmetric unit consists of one 4-(dimethyl-amino)-pyridinium and one octa-aqua-erbium cation balanced by four Cl(-) anions, and one water mol-ecule. The 4-(dimethyl-amino)-pyridinium cation is protonated at the pyridine N atom. The dimethyl-amino group (C/N/C) lies close to the plane of the pyridinium ring, making a dihedral angle of 4.5 (3)°. In the crystal, the [Er(H(2)O)(8)](3+) cations are linked via O-H⋯O and O-H⋯Cl hydrogen bonds, forming two-dimensional networks propagating in the ab plane. These networks are linked via O-H⋯O and O-H⋯Cl hydrogen bonds, forming a three-dimensional network. The 4-(dimethyl-amino)-pyridinium cations are located in the cavities and are linked to the framework via N-H⋯Cl, C-H⋯O and C-H⋯Cl hydrogen bonds.