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The 18O/16O (and 15N/14N) ratio of natural nitrate (NO3-) and nitrite (NO2-) can be used to extract valuable information about their source and fate as environmental contaminants, their metabolism as macronutrients in plants and animals, and their behavior in the N biogeochemical cycle. We developed an accurate, precise, sensitive (minimum sample size: 0.2 μg NO3--equivalent), and reliable (minimal oxygen exchange, loss, or gain) method to selectively isolate and purify nitrate and nitrite from natural water, soil, air, and plant materials by strong anion exchange (SAX) for low- to normal-salinity samples or strong cation exchange (SCX) for high-salinity samples, followed by quantitative conversion to their respective benzyl esters, which can be separated and individually analyzed for δ18O (and potentially δ15N) by gas chromatography (GC)/pyrolysis/GC/isotope-ratio mass spectrometry (IRMS). The method compares favorably with the currently popular bacterial denitrification and chemical reduction methods, in terms of sensitivity and reliability, and has the potential to simultaneously measure δ15N and δ18O of nitrate and nitrite from natural samples of various origins.

A novel strain, 1433T, was isolated from leaves of Chinese red pepper (Huajiao, Zanthoxylum bungeanum Maxim) collected from Gansu province in northwestern China, and was characterised by a polyphasic approach. Cells of strain 1433T were observed to be Gram-stain positive, aerobic, asporogenous, rod shaped, motile and to have peritrichous flagella. The strain was observed to grow at a range of temperatures and pH, 4–45 °C (optimum 28–32 °C) and 6.0–10.0 (optimum pH 6.0–7.0), respectively. Growth was found to occur in the presence of 0–7% (w/v) NaCl [optimum 0–3% (w/v)]. The G+C content of the genomic DNA was determined to be 41.9 mol% and the cell wall peptidoglycan found to contain meso-diaminopimelic acid. The predominant menaquinone was identified as MK-7 and the major polar lipids as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified polar lipid and three unidentified phospholipids. The major cellular fatty acids were identified as iso-C15:0 (31.6%), anteiso-C15:0 (26.9%) and iso-C14:0 (17.1%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 1433T is a member of the genus Bacillus and is closely related to Bacillus aryabhattai DSM 21047T (99.4% sequence similarity) and Bacillus megaterium DSM 32T (99.2%). DNA–DNA relatedness of the novel strain 1433T with B. aryabhattai DSM 21047T and B. megaterium DSM 32T was 33.8 ± 2.8% and 28.9 ± 3.4%, respectively. On the basis of the polyphasic evidence presented, strain 1433T is considered to represent a novel species of the genus Bacillus, for which we propose the name Bacillus zanthoxyli sp. nov. The type strain is 1433T (= CCTCC AB 2016326T = KCTC33730T).

Silvered polyimide films, synthesized by an in-situ self-assembly method, find many applications in the fields of electronics and aerospace materials. In this work, polyimide/siloxanes were introduced into silvered PI films by an in-situ self-assembly process, which were resistant to atomic oxygen. Their atomic oxygen (AO) resistance behaviors were studied, wherein the mass loss of 20% Si-poly(amide acid salt) PAAS film was 30 ug cm−2 after exposure to AO fluence of 1.33 × 1020 O (10.5 h) and 190 ug cm−2 even after 42 h. Additionally, the volume resistivity value of the flexible PI/Ag composite film was 9.9 Ω cm−1 after 260 cycles of bending. The peel strength of PI/Ag/PI composite film was seven times more than that of the coated one (0.7 N cm-1 to 0.1 N cm-1). Moreover, (Dynamic Mechanical Analysis) DMA and (Thermogravimetric Analysis) TGA data also show that the introduction of self-encapsulating PAAS can not only increase the interlayer strength but maintain the performance of PI film. X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy were also employed to test the relative AO resistance behaviors. Thus, the silvered poly(siloxane amic acid) Si-PI composite films have AO resistance, high peel strength and alternating conductivity/ insulative effect, and hence can serve as a flexible printed circuit board for potential applications in low earth orbit.

Six new metal–organic coordination polymers [Mn(H3L)(ox)]·H2O (1), [Zn2(H2L)(pbdc)(μ2-OH)]·2H2O (2), [Co(H3L)(obea)]·3H2O (3), [Ni(H3L)(pbea)] (4), [Co(H3L)(pbea)(H2O)2] (5), and [Co4(H2L)2(pbea)3] (6) were synthesized by reactions of the corresponding metal salt with rigid tripodal ligand 1,3,5-tri(1H-imidazol-4-yl)benzene (H3L) and different dicarboxylic acid of oxalic acid (H2ox), 1,4-benzenedicarboxylic acid (H2pbdc), 1,2-phenylenediacetic acid (H2obea), 1,4-phenylenediacetic acid (H2pbea), respectively. The results of X-ray crystallographic analysis indicate that 1 and 3 are two-dimensional (2D) networks with 63-hcb topology, while 2 is (4,5)-connected three-dimensional (3D) net with Point (Schlafli) symbol of (42·52·72)(42·53·74·8). Complex 4 is a binodal (3,4)-connected 2D network with V2O5-type topology. Complexes 5 and 6 were obtained through controlling reaction temperature, 5 features a one-dimensional (1D) chain, whereas 6 is an unprecedented tetra-nodal (3,4)-connected 3D net with Point (Schl...

Four new inorganic–organic hybrid frameworks [Mn(L)(H2O)2]n (1), {[Co(L)(H2O)3]·2H2O·CH3OH}n (2), {[Zn(L)(H2O)]·H2O}n (3) and [Cd(HL)2]n (4) [H2L = 4-(isonicotinamido)phthalic acid] have been synthesized and characterized by single-crystal X-ray diffraction analysis. Complex 1 has three-dimensional (3D) structure and topology related to SrAl2 (sra) with Schlafli symbol of (42·63·8). And 2 displays (3,3)-connected two-dimensional (2D) network with (4,82) topology, while 3 exhibits a uninodal (3,3)-connected (6,3) 2D network, which is further linked by N–H⋯O hydrogen bonding interactions to give 3D structure with hms topology and Schlafli symbol of (63)(69·8). Complex 4 with partial deprotonated HL− ligands also has a 2D network structure. In addition, the magnetic property of 1, nonlinear optical property of 3 and photoluminescence of 3 and 4 were investigated.

A new imidazolate-bridged dicopper complex [Cu2(L)(Im)](ClO4)3·H2O has been synthesized by reaction of new macrocyclic ligand 6, 20-bis(1H-imidazol-4-ylmethyl)-3, 6, 9, 17, 20, 23-hexaazatricyclo[24.3.1.111,15]hentriaconta-1(29), 11, 13, 15(31), 26(30), 27-hexaene (L) with Cu(ClO4)2⋅6H2O and imidazole, and structurally characterized as a model compound of Cu2Zn2-SOD. There is antiferromagnetic interaction with g = 2.08, − 2 J = 66.5 cm− 1 between the two imidazolate-bridged Cu(II) atoms. The complex displays moderate SOD activity with IC50 of 1.42 μM.

Two new 3d-3d homo- and heterometallic coordination polymers with mixed organic ligands, namely, [Zn2(IBC)(BTC)(H2O)]·H2O (1) and [CdCo(IBC)(BTC)(H2O)] (2) [HIBC = 3,5-di(1H-imidazol-1-yl)benzoic acid, H3BTC = 1,3,5-benzenetricarboxylic acid], have been synthesized and fully characterized by X-ray diffraction, IR, elemental analysis, thermogravimetric analysis, photoluminescence, and magnetic measurements. Complex 1 with homonuclear Zn(II) is a rare three-dimensional (3D) (3,6)-connected rtl (rutile) framework with [Zn2O2] and [Zn2(OCO)2] two different kinds of binuclear Zn(II) secondary building units (SBUs). While complex 2 with heteronuclear Cd(II) and Co(II) atoms is a 3D framework based on [Cd2O2] and [Co2O2] SBUs. In 2, the SBUs are extended into an infinite eight-connected rare hex-type (hexagonal-type) network. The binuclear [Co2O2] SBU in 2 shows antiferromagnetic interactions. Both 1 and 2 were constructed by the same ligands, however with completely different structures and topologies, the resu...

A new three-dimensional nickel(II) metal-organic framework [Ni(INAIP)(H2O)2]n · nH2O (1) [H2INAIP = 5-(isonicotinamido)isophthalic acid] was synthesized under hydrothermal conditions, and characterized by single-crystal X-ray structure determination, thermogravimetric analysis, X-ray powder diffraction, IR and magnetic studies. The compound 1 has (10, 3)-b topology with not well known fourfold interpenetration, in which both Ni(II) atoms and INAIP2− ligands act as three-connected nodes.

Hydrothermal reactions of cadmium(II) or silver(I) salt, NaN 3 , 4-(imidazol-1-ylmethyl)benzonitrile (IBN) yield three coordination complexes, [Cd(L) 2 (H 2 O) 2 ]·3H 2 O ( 1 ), [Cd 3 (L) 5 (OH)] ( 2 ) and [Ag 2 (L) 2 ] ( 3 ) where HL=1-(5-tetrazolyl)-4-(imidazol-1-ylmethyl)benzene. The crystal structure analysis revealed that 1 has 1D hinged-chain structure containing 24-membered ring with a Cd···Cd intra-chain distance of 13.18 A, while 2 is 1D ladder-like chain with Cd 3 O core. However, the complex 3 is a 3D 4-connected framework with Schlafli symbol of (4 2 ·6 3 ·8)(4 3 ·6 2 ·8). The L − ligand was found to show four different coordination modes in 1 – 3 , as 2-, 3- and 4-connector, respectively. The results indicate that the coordination modes of the ligand and metal centers with different coordination geometry have great influence on the structures of the complexes. In addition, the photoluminescence of the complexes were studied in the solid state at room temperature.

Two novel interpenetrated coordination polymers, [Zn(IBA)2]n (1) and {[Cd(IBA)2(H2O)]·4H2O}n (2), have been synthesized by using 4-imidazole-benzoic acid (HIBA) as ligand under hydrothermal conditions. Complex 1 crystallizes in a chiral space group and has a two-fold interpenetrated 2D network structure with (4,4) topology, while complex 2 is a 3D porous dia network with four nets interpenetrating each other. The SHG activity of 1 and the photoluminescent property of 2 have been investigated.

Six new three-dimensional (3D) Cd(II) coordination polymers, {[Cd2(L)3](NO3)4·6H2O}n (1), {[Cd2(L)3](ClO4)4·2H2O}n (2), {[Cd2(L)3](BF4)4·2H2O}n (3), {[Cd(L)Cl2]·2H2O}n (4), {[Cd2(L)2(SO4)2(H2O)]·2H2O}n (5) and {[Cd2(L)(SO4)2(H2O)3]·4H2O}n (6), have been solvothermally synthesized by reactions of the corresponding Cd(II) salts with flexible tetradentate ligand 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene (L), respectively. The X-ray diffraction analysis revealed that the isostructural 1, 2 and 3 have 3D framework structures with (46·66·83)2(42·63·8)3 topology. Complex 4 has a different 3D framework structure with (65·8) topology, while 5 and 6 possess pillared-layer and plywood-like 3D framework structures, respectively. The distinct structures of 1 (2, 3), 4 and 5 indicate that the counter anions with different coordination abilities play an important role in the formation of coordination polymers. Complexes 5 and 6, synthesized by the same reactants in the same solvent, have different structures due to the different metal/ligand ratio. In addition, the results also demonstrated that the flexible tetradentate ligand L can adopt varied conformations and coordination modes to form complexes with different structures. L adopts up,up,down,down-conformation in 1–3, while in 4, it has a up,down-conformation. It is interesting that two different conformations of up,down,down,up- and H-type of L coexist in 5. In the case of 6, L has H-type conformation. Furthermore, the reversible anion exchange property of 1 was studied.

Complete and partial deprotonation of new ligand 4-[(1H-imidazol-4-yl)methylamino]benzoic acid (H 2 L) under hydrothermal conditions lead to the formation of two novel coordination polymers [ZnL] n ( 1 ) and [Ag(HL)] n ( 2 ). Complex 1 displays a rare three-dimensional (3,6)-connected rtl framework with (4 · 6 2 ) 2 (4 2 · 6 10 · 8 3 ) topology, while 2 has a one-dimensional chair-like structure including significant argentophilic Ag–Ag interactions. Both 1 and 2 show remarkable thermal stability and complex 1 was found to show strong blue luminescence with emission maxima at 381 nm upon excitation at 347 nm in the solid state at room temperature.

Seven new coordination polymers {[Cu3(tib)4](NO3)6·4.94H2O}n (1), {[Cu2(tib)2(SO4)2]·2EtOH·2H2O}n (2), [Cu(tib)Cl2]n (3), {[Cd(tib)2](NO3)2·4H2O}n (4), {[Cd(tib)(H2O)2(SO4)]·EtOH·H2O}n (5) {[Co(tib)(H2O)2(SO4)]·EtOH·H2O}n (6), and {[Ni(tib)(H2O)2(SO4)]·EtOH·H2O}n (7) (EtOH = ethanol) were prepared by reactions of flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)benzene (tib) with the corresponding metal salts. Their structures were determined by X-ray crystallography. The different structures of 1−3 as well as 4 and 5 indicate that the counteranions play an important role in the construction of coordination polymers. The distinct structures of Cu(II) and Cd(II) complexes with the same counteranion demonstrate that the metal centers with different coordination geometry have a significant influence on the structures. The same 1D chain structure of 5−7 indicated that the metal centers with the same octahedral coordination geometry do not affect the structure of the complexes. On the other hand, ligand...

Four copper(II) complexes were synthesized by reactions of new imidazole-containing polyamine ligand N1-(2-aminoethyl)-N1-(1H-imidazol-4-ylmethyl)-ethane-1,2-diamine (HL) with Cu(ClO4)2 · 6H2O under different pH and their structures were characterized by X-ray crystallography. Interestingly, the complexes have diverse structures from protonated ligand [H3(HL)][CuCl4] · Cl (1), dinuclear [Cu2(HL)2Cl](ClO4)3 · H2O (2), one-dimensional chain polynuclear {[Cu(L)](ClO4)}n (3) to cyclic-tetranuclear [Cu4(L)4](ClO4)4 · 3CH3CN (4) coordination compounds by varying reaction pH from acidic to basic. The results indicate that the reaction pH has great impact on the formation and structure of the complexes. The magnetic measurements show that there are antiferromagnetic interactions between the Cu(II) centers with g = 2.09, J = −39.0 cm−1 and g = 2.17, J = −36.8 cm−1 for 3 and 4, respectively.

Two novel inorganic–organic hybrid frameworks [Cu2(BPTCA)(H2O)2 · 2H2O]n (1) and [Cd2(BPTCA)(μ-OH2)2]n (2) were obtained by reactions of 4,4′-bipyridine-2,2′,6,6′-tetracarboxylic acid (H4BPTCA) with copper(II) and cadmium(II) salts, respectively and characterized by X-ray single crystal structure analysis. Complex 1 has a two-dimensional ladder-like structure containing infinite –Cu–O– chains. The magnetic susceptibility data of 1 show the intra-chain ferromagnetic exchange coupling resulting from the orthogonal arrangement of copper magnetic orbital within the –Cu–O– infinite chain. Complex 2 is a three-dimensional framework in which the –Cd–(O)2– zigzag-chains are linked by BPTCA4−. The photoluminescence property of 2 is studied.

The title compound of [Ni(H2O)6(NaSO4)2] has been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction. The compound crystallizes in space group P21/c of the monoclinic system in a cell at 293.2 K of a=6.1820(12) A, b=12.316(3) A, c=9.0890(18) A, β=106.03(3)°, and V=665.1(2) A3. In the title compound, each SO4 tetrahedron coordinates with three Na(I) ions and each Na(I) connects to three SO4 tetrahedrons. Such a coordinate model makes up a two-dimensional network having two different kinds of rings and, in the bigger rings, the [Ni(H2O)6]2+ ions are located. In the solid state, some hydrogen bonds connect the title compound to form three-dimensional networks, stabilizing the crystal structure. Thermogravimetric analysis shows that there are three steps of weight loss from the beginning of 110 °C and the residue may be the mixtures of NiO2 and Na2O.

Three new coordination polymers [Mn4(bptca)2(titmb)(H2O)7]·DMF·4H2O (1), [Ni2(bptca)(titmb)2]·13H2O (2) and [Co2(bptca)(titmb)2]·13H2O (3) were constructed from 4,4′-bipyridine-2,2′,6,6′-tetracarboxylic acid (H4bptca) and 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (titmb) under hydrothermal conditions. Single crystal X-ray diffraction analysis shows that 1 contains [Mn4(μ2-OCO)4] subunits linked through organic ligands to form a two-dimensional (2D) double-layer structure, while 2 and 3 are isostructural and exhibit a unique three-dimensional (3D) framework with open channels resided by water molecules. The magnetic behavior of 1 and sorption property of 2 have been investigated.

Nine new coordination polymers [Mn(L)(OX)] (1), [Zn(L)(MBDC)] (2), [Zn(L)(BPDA)] (3), [Co3(L)2(BTA)2]·2H2O (4), [Co2(L)2(BTCA)]·2H2O (5), [Ni(L)(e,a-cis-1,2-CHDC)]·2H2O (6), [Co(L)(e,a-cis-1,4-CHDC)] (7), [Co(L)(e,e-trans-1,4-CHDC)]·2H2O (8) and [Co(L)(e,e,e-cis-1,3,5-HCHTC)]·0.45H2O (9) were obtained by reactions of varied metal salts with 1,4-di(1H-imidazol-4-yl)benzene (L) in the presence of corresponding auxiliary ligands of oxalic acid (H2OX), 5-methyl-1,3-benzenedicarboxylic acid (H2MBDC), 4,4′-biphenyldicarboxylic acid (H2BPDA), benzene-1,3,5-triacetic acid (H3BTA), 1,2,4,5-benzenetetracarboxylic acid (H4BTCA), cis-1,2-cyclohexanedicarboxylic acid (cis-1,2-H2CHDC), cis-/trans-1,4-cyclohexanedicarboxylic acid (cis-/trans-1,4-H2CHDC) and cis-1,3,5-cyclohexane tricarboxylic acid (cis-1,3,5-H3CHTC), respectively. Complex 1 has a one-dimensional (1D) chain structure and 2 has a two-dimensional (2D) network with 63-hcb topology. Complex 3 is a complicated uninodal 4-connected three-dimensional (3D) net with Point (Schlafli) symbol (4·6·83·10)(4·63·82)(63·103)(64·82) while 4 is a (3,8)-connected tfz-d 3D net with Point (Schlafli) symbol (43)2(46·618·84) based on the trinuclear Co(II) secondary building units (SBUs). Complex 5 is a 3-fold interpenetrating mog net with Point (Schlafli) symbol of (4·64·8)2(42·62·82), while 6 is a 2D net with (4,4) topology based on binuclear SBUs. In contrast to the 2D network of 7 with e,a-cis-1,4-CHDC2−, 8 with e,e-trans-1,4-CHDC2− is a 5-fold interpenetrating 66-dia 3D net. Complex 9 has a 1D ladder-like chain structure with a stable conformation from the e,e,e-cis-1,3,5-HCHTC2− ligand. Complexes 2 and 3 exhibit intense light blue emission in the solid state at room temperature and the results of magnetic measurements showed that there are antiferromagnetic interactions in 1.

Six new metal–organic coordination polymers [Ni(L)(adip)(H2O)] (1), [Co(L)(adip)]·H2O (2), [Cd2(L)(adip)2] (3), [Ni(L)(oxba)]·H2O (4), [Co(L)(obea)]·H2O (5) and [Mn3(L)2(bta)2]·2H2O (6) were synthesized by reactions of the corresponding metal salt with the rigid ligand 1,4-di(1H-imidazol-4-yl)benzene (L) and different multi-carboxylic acids of adipic acid (H2adip), 4,4′-oxybis(benzoic acid) (H2oxba), 1,2-phenylenediacetic acid (H2obea), benzene-1,3,5-triacetic acid (H3bta), respectively. The structures of the complexes were determined by single crystal X-ray diffraction analysis. Complexes 1–4 have entangled structures with different topologies: 1 is a 2-fold interpenetrating two-dimensional (2D) network with (4,4) topology containing rare meso-helical chains; 3 is a three-dimensional (3D) uninodal 8-connected self-penetrating net; 2 and 4 are a 3-fold interpenetrating dmp 3D net. Complex 5 is a 2D network with (4,4) topology, while 6 is a typical (3,8)-connected tfz-d 3D net based on the trinuclear Mn(II) subunits. Complex 3 exhibits intense light blue emission in the solid state at room temperature and the results of magnetic measurements show that there are antiferromagnetic interactions in 6.

Three unprecedented metal-organic frameworks [M3(tib)2(CTC)2]·nH2O [M = Co(II), n = 2 (1); Mn(II), n = 2.92 (2) and Ni(II), n = 2 (3)] based on M3(OCO)6 trinuclear secondary building units (SBUs) have been successfully synthesized by reactions of corresponding metal salt with mixed flexible triacid of 1,3,5-cyclohexanetricarboxylic acid (H3CTC) and rigid imidazol-containing ligand 1,3,5-tris(1-imidazolyl)benzene (tib) under hydrothermal conditions. In 1–3, the CTC3− ligands link the SBUs to form two-dimensional (2D) ‘hxl’ (hexagonal lattice) networks and the tib ligands further pillar the 2D layers leading to the formation of three-dimensional frameworks, which are firstly reported uninodal 10-connected bct nets. The magnetic measurements showed that 1 and 3 exhibit ferromagnetic coupling interactions between the adjacent metal centers with g = 2.63, D = 66.69 cm−1, zJ = 0.68 cm−1 and g = 2.22, J = 6.25 cm−1, zj′ = −0.053 cm−1, respectively, while 2 has antiferromagnetic interaction between the Mn(II) ions with g = 2.01, J = −0.57 cm−1, zj′ = 1.3 × 10−4 cm−1.

Two novel cobalt(II) complexes [Co(L)(NO3)] (1) and [Co(L)(H2O)2]ClO4 (2) were synthesized by reactions of 3,5-di(1H-imidazol-1-yl)benzoic acid (HL) with corresponding cobalt(II) salts, and their structures were determined by single crystal X-ray diffraction analysis. In the title complexes, the carboxylate group of L− ligand adopts a µ2–ŋ1:ŋ1-bridging mode to connect two cobalt(II) atoms, and each L− ligand acts as a 4-connector, and the cobalt(II) has distorted octahedral coordination geometry. In 1, one oxygen atom of the nitrate anion links two cobalt(II) atoms to complete a 3D structure which is a binodal (4,6)-connected net with Schlafli symbol of (3·42·52·6)(32·42·52·64·74·8). While in 2, the 3D structure has topology related to SrAl2, CeCu2 and KHg2 with Schlafli symbol of (42·63·8) and there are 1D channels filled with perchlorate anions. The results revealed that the nature of the counteranions, such as their shape, size and coordination ability, has a remarkable influence on the structure of the complexes. The results of the magnetic measurements showed that there are antiferromagnetic interactions between the neighboring Co(II). Furthermore, complex 2 exhibited a modest second-harmonic-generation (SHG) efficiency and anion-exchange property.