A three-dimensional framework in 2,2'-biimidazolium bis(2,2'-biimidazole-κ(2)N,N')bis(biphenyl-2,4'-dicarboxylato-κO)manganese(II) hexahydrate.

In the title salt, (C(6)H(8)N(4))[Mn(C(14)H(8)O(4))(2)(C(6)H(6)N(4))(2)]·6H(2)O, the Mn(II) atom lies on an inversion centre and is coordinated by four N atoms from two 2,2'-biimidazole (biim) ligands and two O atoms from two biphenyl-2,4'-dicarboxylate (bpdc) anions to give a slightly distorted octahedral coordination, while the cation lies about another inversion centre. Adjacent [Mn(bpdc)(2)(biim)(2)](2-) anions are linked via two pairs of N-H...O hydrogen bonds, leading to an infinite chain along the [100] direction. The protonated [H(2)biim](2+) moiety acts as a charge-compensating cation and space-filling structural subunit. It bridges two [Mn(bpdc)(2)(biim)(2)](2-) anions through two pairs of N-H...O hydrogen bonds, constructing two R(2)(2)(9) rings, leading to a zigzag chain in the [2-1-1] direction, which gives rise to a ruffled set of [H(2)biim](2+)[Mn(bpdc)(2)(biim)(2)](2-) moieties in the [01-1] plane. The water molecules give rise to a chain structure in which O-H...O hydrogen bonds generate a chain of alternating four- and six-membered water-oxygen R(4)(2)(8) and R(6)(6)(12) rings, each lying about independent inversion centres giving rise to a chain along the [100] direction. Within the water chain, the (H(2)O)(6) water rings are hydrogen bonded to two O atoms from two [Mn(bpdc)(2)(biim)(2)](2-) anions, giving rise to a three-dimensional framework.

catena-Poly[[nickel(II)-µ-1,3-dimethyl-2,6-dioxo-7H-purinato-κN:N] hydroxide].

The title complex, {[Ni(C(7)H(7)N(4)O(2))]OH}(n), has been prepared through hydro-thermal synthesis. The asymmetric unit contains one [Ni(TH)](+) cation (TH is the theophylline anion) and one hydroxide anion. The Ni(2+) ion is coordinated by two N atoms from two neighboring theophylline anions. The alternating linkage of the Ni(2+) cation and theophylline anion results in a one-dimensional chain along the [010] direction. Intermolec-ular O-H⋯O hydrogen bonds are present n the crystal structure.

Bis(4,4'-methyl-enedianilinium) naphthalene-1,5-disulfonate dihydrate.

The asymmetric unit of the title salt, C(13)H(16)N(2) (2+)·C(10)H(6)O(6)S(2) (2-)·2H(2)O, consists of one dication located on a general position, half each of two centrosymmetric dianions, and two uncoordinated water mol-ecules in general positions. In the dication, the dihedral angle between the benzene rings is 74.67 (6)°. The cations and anions inter-act through N-H⋯O hydrogen bonds. The NH(3) (+) functional groups are also involved in N-H⋯O hydrogen bonds with the water mol-ecules, forming an infinite three-dimensional framework in the crystal structure.

Bis(benzimidazolium) naphthalene-1,5-disulfonate trihydrate.

The title compound, 2C(7)H(7)N(2) (+)·C(10)H(6)O(6)S(2) (2-)·3H(2)O, consists of two crystallographically independent benzimidazolium cations, two independent naphthalene-1,5-disulfonate dianions (both generated by inversion) and three water mol-ecules. These components construct an infinite three-dimensional framework in the crystal structure via O-H⋯O and N-H⋯O hydrogen bonds.

[Compositions, Sources and Health Risks of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Dusts from Driving-schools in a City of Henan Province, China].

The contamination of polycyclic aromatic hydrocarbons (PAHs) in surface dusts attracts great attentions due to their properties of threatening human health. Twenty-nine surface dust samples were collected from driving-schools in a city of Henan. Concentrations of 16 priority PAHs were analyzed by gas chromatography-mass spectrometry (GC-MS). The health risks exposed to dust PAHs for three different scenarios (working for 5 a, 10 a and 20 a in driving-school) were estimated by the health risk assessment model (ILCRs). Source identification was analyzed by diagnostic ratio, composition analysis, and principal component analysis. The results showed that concentrations of the ∑PAHs in dusts ranged from 198.21 to 3400.89 µg·kg-1, with a mean of 908.72 µg·kg-1. Among individual PAHs, the contents of naphthalene (Nap), phenanthrene (Phe), anthracene (Ant) and fluoranthene (Flu) were higher, and the content of dibenzo[a, h]anthracene (DBA) was the lowest. The dominant compounds were 2-3 ring PAHs, which accounted for 55.79%, while the 4-6 ring PAHs accounted for 44.21%. The health risks exposed to PAHs in dust in three different scenarios were 9.27×10-8, 1.85×10-7, and 3.71×10-7 respectively; only sample J11 was with potential health risk in scenario 3, and the other samples were all without risks. Average daily doses by dermal contact of dust particles for the PAHs was the main exposure way. PAHs in dusts of driving-school were mainly originated from the combustion of fossil fuels and mixture combustion. The major sources of dust PAHs in farmland area driving-schools were natural gas and diesel combustion (56.44%), coal combustion (26.55%), gasoline combustion and the leakage (17.01%); dust PAHs in industrial area driving-schools were from mixture combustion (76.26%), gasoline combustion and the leakage (22.85%), coking and coal combustion (0.89%); and dust PAHs in mixed area driving-schools were from coal combustion (45.57%), natural gas and diesel combustion (45.41%), gasoline combustion and the leakage (9.02%). The concentrations and health risks of heavy metals in dusts were closely related to the surroundings around driving-schools and the previous land use status.