Study on thermal decomposition kinetics of azobenzene-4,4′-dicarboxylic acid by using compensation parameter method and nonlinear fitting evaluation

Recently,azobenzene-4,4'-dicarboxylic acid(ADCA)has been produced gradually for use as an organic synthesis or pharmaceutical intermediate due to its eminent performance.With large quantities put into application in the future,the thermal stability of this substance during storage,transportation,and use will become quite important.Thus,in this work,the thermal decomposition behavior,thermal decomposition kinetics,and thermal hazard of ADCA were investigated.Experiments were conducted by using a SENSYS evo DSC device.A combination of differential iso-conversion method,compensation parameter method,and nonlinear fitting evaluation were also used to analyze thermal kinetics and mechanism of ADCA decomposition.The results show that when conversion rate α increases,the activation energies of ADCA's first and main decomposition peaks fall.The amount of heat released during decomposition varies between 182.46 and 231.16 J·g^(-1).The proposed kinetic equation is based on the Avrami-Erofeev model,which is consistent with the decomposition progress.Applying the Frank-Kamenetskii model,a calculated self-accelerating decomposition temperature of 287.0℃is obtained.

Maternal supplementation with n-3 fatty acids affects placental lipid metabolism, inflammation, oxidative stress, the endocannabinoid system, and the neonate cytokine concentrations in dairy cows

Background The placenta plays a crucial role in supporting and influencing fetal development.We compared the effects of prepartum supplementation with omega-3(n-3)fatty acid(FA)sources,flaxseed oil(FLX)and fish oil(FO),on the expression of genes and proteins related to lipid metabolism,inflammation,oxidative stress,and the endocannabinoid system(ECS)in the expelled placenta,as well as on FA profile and inflammatory response of neonates.Late-pregnant Holstein dairy cows were supplemented with saturated fat(CTL),FLX,or FO.Placental cotyledons(n=5)were collected immediately after expulsion,and extracted RNA and proteins were analyzed by RTPCR and proteomic analysis.Neonatal blood was assessed for FA composition and concentrations of inflammatory markers.Results FO increased the gene expression of fatty acid binding protein 4(FABP4),interleukin 10(IL-10),catalase(CAT),cannabinoid receptor 1(CNR1),and cannabinoid receptor 2(CNR2)compared with CTL placenta.Gene expression of ECS-enzyme FA-amide hydrolase(FAAH)was lower in FLX and FO than in CTL.Proteomic analysis identified 3,974 proteins;of these,51–59 were differentially abundant between treatments(P≤0.05,|fold change|≥1.5).Top canonical pathways enriched in FLX vs.CTL and in FO vs.CTL were triglyceride metabolism and inflammatory processes.Both n-3 FA increased the placental abundance of FA binding proteins(FABPs)3 and 7.The abundance of CNR1 cannabinoid-receptor-interacting-protein-1(CNRIP1)was reduced in FO vs.FLX.In silico modeling affirmed that bovine FABPs bind to endocannabinoids.The FLX increased the abundance of inflammatory CD44-antigen and secreted-phosphoprotein-1,whereas prostaglandin-endoperoxide synthase 2 was decreased in FO vs.CTL placenta.Maternal FO enriched neonatal plasma with n-3 FAs,and both FLX and FO reduced interleukin-6 concentrations compared with CTL.Conclusion Maternal n-3 FA from FLX and FO differentially affected the bovine placenta;both enhanced lipid metabolism and modulated oxidative stress,however,FO increased some transcriptional ECS components,possibly related to the increased FABPs.Maternal FO induced a unique balance of pro-and anti-inflammatory components in the placenta.Taken together,different sources of n-3 FA during late pregnancy enhanced placental immune and metabolic processes,which may affect the neonatal immune system.

Traditional Chinese medicine Pien-Tze-Huang ameliorates LPS-induced sepsis through bile acid-mediated activation of TGR5-STAT3-A20 signalling

Pien Tze Huang(PZH),a class-1 nationally protected traditional Chinese medicine(TCM),has been used to treat liver diseases such as hepatitis;however,the effect of PZH on the progression of sepsis is unknown.Here,we reported that PZH attenuated lipopolysaccharide(LPS)-induced sepsis in mice and reduced LPS-induced production of proinflammatory cytokines in macrophages by inhibiting the activation of mitogen-activated protein kinase(MAPK)and nuclear factor-kappa B(NF-κB)signalling.Mechanistically,PZH stimulated signal transducer and activator of transcription 3(STAT3)phosphorylation to induce the expression of A20,which could inhibit the activation of NF-κB and MAPK signalling.Knockdown of the bile acid(BA)receptor G protein-coupled bile acid receptor 1(TGR5)in macrophages abolished the effects of PZH on STAT3 phosphorylation and A20 induction,as well as the LPS-induced inflammatory response,suggesting that BAs in PZH may mediate its anti-inflammatory effects by activating TGR5.Consistently,deprivation of BAs in PZH by cholestyramine resin reduced the effects of PZH on the expression of phosphorylated-STAT3 and A20,the activation of NF-κB and MAPK signalling,and the production of proinflammatory cytokines,whereas the addition of BAs to cholestyramine resin-treated PZH partially restored the inhibitory effects on the production of proinflammatory cytokines.Overall,our study identifies BAs as the effective components in PZH that activate TGR5-STAT3-A20 signalling to ameliorate LPS-induced sepsis.

Caffeic acid hinders the proliferation and migration through inhibition of IL-6 mediated JAK-STAT-3 signaling axis in human prostate cancer

Background:Caffeic acid(CA)is considered a promising phytochemical that has inhibited numerous cancer cell proliferation.Therefore,it is gaining increasing attention due to its safe and pharmacological applications.In this study,we investigated the role of CA in inhibiting the Interleukin-6(IL-6)/Janus kinase(JAK)/Signal transducer and activator of transcription-3(STAT-3)mediated suppression of the proliferation signaling in human prostate cancer cells.Materials and Methods:The role of CA in proliferation and colony formation abilities was studied using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide(MTT)assay and colony formation assays.Tumour cell death and cell cycle arrest were identified usingflow cytometry techniques.CA treatment-associated protein expression of mitogen-activated protein kinase(MAPK)families,IL-6/JAK/STAT-3,proliferation,and apoptosis protein expressions in PC-3 and LNCaP cell lines were measured using Western blot investigation.Results:We have obtained that treatment with CA inhibits prostate cancer cells(PC-3 and LNCaP)proliferation and induces reactive oxygen species(ROS),cell cycle arrest,and apoptosis cell death in a concentration-dependent manner.Moreover,CA treatment alleviates the expression phosphorylated form of MAPK families,i.e.,extracellular signal-regulated kinase 1(ERK1),c-Jun N-terminal kinase(JNK),and p38 in PC-3 cells.IL-6 mediated JAK/STAT3 expressions regulate the proliferation and antiapoptosis that leads to prostate cancer metastasis and migration.Therefore,to mitigate the expression of IL-6/JAK/STAT-3 is considered an important target for the treatment of prostate cancer.In this study,we have observed that CA inhibits the expression of IL-6,JAK1,and phosphorylated STAT-3 in both PC-3 and LNCaP cells.Due to the inhibitory effect of IL-6/JAK/STAT-3,it resulted in decreased expression of cyclin-D1,cyclin-D2,and CDK1 in both PC-3 cells.In addition,CA induces apoptosis by enhancing the expression of Bax and caspase-3;and decreased expression of Bcl-2 in prostate cancer cells.Conclusions:Thus,CA might act as a therapeutical application against prostate cancer by targeting the IL-6/JAK/STAT3 signaling axis.

Landscape of Sequence Variations in Homologous Copies of FAD2 and FAD3 in Rapeseed(Brassica napus L.)Germplasm with High/Low Linolenic Acid Trait

Genetic manipulation(either restraint or enhancement)of the biosynthesis pathway ofα-linolenic acid(ALA)in seed oil is an important goal in Brassica napus breeding.B.napus is a tetraploid plant whose genome often har-bors four and six homologous copies,respectively,of the two fatty acid desaturases FAD2 and FAD3,which con-trol the last two steps of ALA biosynthesis during seed oil accumulation.In this study,we compared their promoters,coding sequences,and expression levels in three high-ALA inbred lines 2006L,R8Q10,and YH25005,a low-ALA line A28,a low-ALA/high-oleic-acid accession SW,and the wildtype ZS11.The expression levels of most FAD2 and FAD3 homologs in the three high-ALA accessions were higher than those in ZS11 and much higher than those in A28 and SW.The three high-ALA accessions shared similar sequences with the pro-moters and CDSs of BnFAD3.C4 and BnFAD3.A3.In A28 and SW,substitution of three amino acid residues in BnFAD2.A5 and BnFAD2.C5,an absence of BnFAD2.C1 locus,and a 549 bp long deletion on the BnFAD3.A3 promoter were detected.The profile of BnFAD2 mutation in the two low-ALA accessions A28 and SW is different from that reported in previous studies.The mutations in BnFAD3 in the high-ALA accessions are reported for thefirst time.In identifying the sites of these mutations,we provide detailed information to aid the design of mole-cular markers for accelerated breeding schemes.

Ferulic acid reduces inflammatory response induced by radiation through Sirt1-NLRP3 pathway

Objective:A model of inflammatory damage was induced by radiation to investigate whether ferulic acid(FA)can reduce the inflammatory response through the Sirt1-NLRP3 inflammatory pathway.This will help discover radiation-protective drugs and elucidate the molecular mechanisms related to radiation-induced inflammatory damage.Methods:A mouse model of radiation-induced immunoinflammatory injury was established to verify the anti-inflammatory effects of FA in vivo.C57BL/6J mice were randomly divided into six groups,and 5 Gy whole-body irradiation was used for modeling.Mice were administered a gastric solvent,amifostine,or 25,50,or 100 mg/kg FA daily for 12 days,consecutively,before irradiation.The serum of mice was collected 24 hour after irradiation to observe the content of inflammatory factors interleukin(IL)-1β,IL-18,IL-6,and tumor necrosis factor(TNF)-α.The spleen and thymus tissues of mice were weighed and the organ index was calculated for pathological testing and immunofluorescence detection.Results:FA reduced the radiation-induced decrease in the spleen and thymus indices.FA significantly reduced the secretion of inflammatory factors in the serum and reversed the radiation-induced reduction in lymphocytes in the spleen and thymus of mice.FA activated Sirt1 and inhibited the expression of the NLRP3 inflammasome to alleviate the inflammatory response.Conclusions:FA reduced radiation-induced inflammation in animals,possibly by activating Sirt1 and reducing nucleotide oligomerization domain(NOD)-like receptor thermal protein domain associated protein 3(NLRP3)inflammasome expression,thereby reducing the secretion of inflammatory factors.

Acetic acid additive in NaNO_(3)aqueous electrolyte for long-lifespan Mg-air batteries

Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environmental sustainability,and cost-effectiveness.However,the fast hydrogen evolution reaction(HER)in NaCl-based aqueous electrolytes impairs the performance of Mg-air batteries and leads to poor specific capacity,low energy density,and low utilization.Thus,the conventionally used NaCl solute was proposed to be replaced by NaNO_(3)and acetic acid additive as a corrosion inhibitor,therefore an electrolyte engineering for long-life time Mg-air batteries is reported.The resulting Mg-air batteries based on this optimized electrolyte demonstrate an improved discharge voltage reaching~1.8 V for initial 5 h at a current density of 0.5 mA/cm^(2) and significantly prolonged cells'operational lifetime to over 360 h,in contrast to only~17 h observed in NaCl electrolyte.X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed to analyse the composition of surface film and scanning electron microscopy combined with transmission electron microscopy to clarify the morphology changes of the surface layer as a function of acetic acid addition.The thorough studies of chemical composition and morphology of corrosion products have allowed us to elucidate the working mechanism of Mg anode in this optimized electrolyte for Mg-air batteries.

Understanding the roles of Brønsted/Lewis acid sites on manganese oxide-zeolite hybrid catalysts for low-temperature NH_(3)-SCR

Although metal oxide-zeolite hybrid materials have long been known to achieve enhanced catalytic activity and selectivity in NO_(x)removal reactions through the inter-particle diffusion of intermediate species,their subsequent reaction mechanism on acid sites is still unclear and requires investigation.In this study,the distribution of Brønsted/Lewis acid sites in the hybrid materials was precisely adjusted by introducing potassium ions,which not only selectively bind to Brønsted acid sites but also potentially affect the formation and diffusion of activated NO species.Systematic in situ diffuse reflectance infrared Fourier transform spectroscopy analyses coupled with selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR)reaction demonstrate that the Lewis acid sites over MnO_(x)are more active for NO reduction but have lower selectivity to N_(2)than Brønsted acids sites.Brønsted acid sites primarily produce N_(2),whereas Lewis acid sites primarily produce N_(2)O,contributing to unfavorable N_(2)selectivity.The Brønsted acid sites present in Y zeolite,which are stronger than those on MnO_(x),accelerate the NH_(3)-SCR reaction in which the nitrite/nitrate species diffused from the MnO_(x)particles rapidly convert into the N_(2).Therefore,it is important to design the catalyst so that the activated NO species formed in MnO_(x)diffuse to and are selectively decomposed on the Brønsted acid sites of H-Y zeolite rather than that of MnO_(x)particle.For the physically mixed H-MnO_(x)+H-Y sample,the abundant Brønsted/Lewis acid sites in H-MnO_(x)give rise to significant consumption of activated NO species before their inter-particle diffusion,thereby hindering the enhancement of the synergistic effects.Furthermore,we found that the intercalated K+in K-MnO_(x)has an unexpected favorable role in the NO reduction rate,probably owing to faster diffusion of the activated NO species on K-MnO_(x)than H-MnO_(x).This study will help to design promising metal oxide-zeolite hybrid catalysts by identifying the role of the acid sites in two different constituents.

Catalytic Performance of Aquathermolysis and Viscosity Reduction of Heavy Oil over a WO_(3)/ZrO_(2) Solid Acid

Tungstated zirconia(WO_(3)/ZrO_(2))solid acid catalysts with different WO_(3) contents were prepared by a hydrothermal method and then used in the catalytic aquathermolysis of heavy oil from Xinjiang.The WO_(3)/ZrO_(2) solid acid catalyst was characterized by a range of characterization methods,including X-ray diffraction,NH3-temperature programmed desorption,and pyridine infrared spectroscopy.The WO_(3) content of the WO_(3)/ZrO_(2) catalysts had an important impact on the structure and property of the catalysts.When the WO_(3) mass fraction was 20%,it facilitated the formation of tetragonal zirconia,thereby enhancing the creation of robust acidic sites.Acidity is considered to have a strong impact on the catalytic performance of the aquathermolysis of heavy oil.When the catalyst containing 20%WO_(3) was used to catalyze the aquathermolysis of heavy oil under conditions of 14.5 MPa,340℃,and 24 h,the viscosity of heavy oil decreased from 47266 to 5398 mPa·s and the viscosity reduction rate reached 88.6%.The physicochemical properties of heavy oil before and after the aquathermolysis were analyzed using a saturates,aromatics,resins,and asphaltenes analysis,gas chromatography,elemental analysis,densimeter etc.After the aquathermolysis,the saturate and aromatic contents significantly increased from 43.3%to 48.35%and 19.47%to 21.88%,respectively,with large reductions in the content of resin and asphaltene from 28.22%to 25.06%and 5.36%to 2.03%,respectively.The sulfur and nitrogen contents,and the density of the oil were significantly decreased.These factors were likely the main reasons for promoting the viscosity reduction of heavy oil during the aquathermolysis over the WO_(3)/ZrO_(2) solid acid catalysts.

Branched-chain fatty acids from goat milk alleviate ulcerative colitis via the TLR4/NF-κB/NLRP3 pathway

Branched-chain fatty acids(BCFAs)are new bioactive fatty acids with anti-inflammatory properties.However,the role of BCFAs in alleviating ulcerative colitis has not been clarified.Herein,we evaluated the protective effect of BCFAs from goat milk in mice with colitis induced using dextran sodium sulfate(DSS)and explored the corresponding mechanism.These results show that BCFAs extracted from goat milk can significantly alleviate weight loss in mice,and reduce the disease activity index and the activity of myeloperoxidase while increasing the content of antioxidant enzymes in colon tissue and reducing the oxidation stress response.These data also show that BCFAs can down-regulate the gene and protein expression of the toll-like receptor 4(TLR4)/nuclear factorκB p65(NF-κB p65)/NOD-like receptor thermal protein domain associated protein 3(NLRP3)signaling pathway,and at the same time significantly reduce the expression of pro-inflammatory factors tumor necrosis factorα(TNF-α),interleukin 1β(IL-1β),and IL-18 in colon tissue,and significantly increase the expression of the anti-inflammatory factor IL-10.In conclusion,these results demonstrated that BCFAs in goat milk exerted effects on colitis-related inflammatory cytokines and inhibited inflammation by inducing the TLR4/NF-κB/NLRP3 pathway to alleviate DSS-induced ulcerative colitis.This study provides evidence for the potential of BCFAs as bioactive fatty acids in food products and to ameliorate ulcerative colitis development in mice.

Elaidic acid-induced intestinal barrier damage led to gut-liver axis derangement and triggered NLRP3 inflammasome in the liver of SD rats

Previous studies have shown that trans fatty acids(TFA) are associated with several chronic diseases,the gut microbiota is directly influenced by dietary components and linked to chronic diseases.Our research investigated the effects of elaidic acid(EA),a typical TFA,on the gut microbiota to understand the underlying mechanisms of TFA-related chronic diseases.16S rDNA gene sequencing on faecal samples from Sprague-Dawley rats were performed to explore the composition change of the gut microbiota by EA gavage for 4 weeks.The results showed that the intake of EA increased the abundance of well-documented harmful bacteria,such as Proteobacteria,Anaerotruncus,Oscillibacter and Desulfovibrionaceae.Plus,EA induced translocation of lipopolysaccharides(LPS) and the above pathogenic bacteria,disrupted the intestinal barrier,led to gut-liver axis derangement and TLR4 pathway activation in the liver.Overall,EA induced intestinal barrier damage and regulated TLR4-MyD88-NF-κB/MAPK pathways in the liver of SD rats,leading to the activation of NLRP3 inflammasome and inflammatory liver damage.

Oleanolic acid inhibits colon cancer cell stemness and reverses chemoresistance by suppressing JAK2/STAT3 signaling pathway

Background:Oleanolic acid(OA),a pentacyclic triterpenoid exhibiting specific anti-cancer properties and highly effective antioxidant activity,was isolated from traditional Chinese medicinal herbs.Conversely,the OA that impacts colon cancer(CC)cells and its underlying mechanisms remain poorly understood.Methods:The cytotoxic effect of OA alone or OA-5-Fluorouracil(5-FU)combination on normal and CC cells was analyzed by methyl thiazolyl diphenyl-tetrazolium bromide(MTT).Then,the impact of OA on CC cell lines(LoVo and HT-29)proliferation and stemness were measured using colon formation and tumorsphere formation assays.Octamer-binding transcription factor 4(Oct4),Prominin-1(CD133),Nanog,and transcription factor SOX-2(SOX2)are cell stemness-related indicators whose expression was assessed usingfluorescence qPCR assay,Western blotting,and immunohistochemistry.The effect of OA on the proliferative potency of CC cells was evaluated using an in vivo model.Results:The stem-like characteristics and clone production of colon cancer cells were markedly reduced by OA alone or in combination with OA-5-FU.Moreover,OA increases the susceptibility of CC cells to 5-FU by blocking the cell stemness-related markers(CD133,Nanog,SOX2,and Oct4)expression levels both in vitro and in vivo,as well as by inactivating the activator of transcription 3(STAT3 signaling)and Janus kinase 2/signal transducer(JAK2).Conclusion:Thesefindings imply that oleanolic acid,both in vitro and in vivo,suppresses the JAK2/STAT3 pathway,which in turn reverses chemoresistance and decreases colon cancer cell stemness.Therefore,by reducing the recommended amount of 5-FU,this strategy may improve chemotherapeutic effectiveness and minimize undesired side effects.

Gossypol acetic acid regulates leukemia stem cells by degrading LRPPRC via inhibiting IL-6/JAK1/STAT3 signaling or resulting mitochondrial dysfunction

BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.

Synthesis,Crystal Structure and Magnetic Behavior of a New Manganese(Ⅱ) Coordination Polymer [Mn(DPPZ)(PZDC)(H_2O)] (DPPZ=Dipyrido[3,2-a:2',3'-c]-phenazine and H_2PZDC=Pyrazine-2,3-dicarboxylic Acid)

The title complex, [Mn（DPPZ）（PZDC）（H2O）] 1 （DPPZ = dipyrido[3,2 -a：2＇,3＇- c]phenazine and H2PZDC = pyrazine-2,3-dicarboxylic acid）, has been hydrothermally synthesized and structurally characterized by X-ray single-crystal diffraction, elemental analyses, IR, TG- DTA and magnetic susceptibility measurement. It crystallizes in triclinic, space group P1^- with a = 6.6842（5）, b = 7.5741（6）, c = 20.5755（15）A, α = 90.1160（10）, β = 97.0560（10）, γ = 97.3350（10）°, V= 1025.16（13）A^3, Z = 2, MnC24H14N6O5, Mr= 521.35, Dc= 1.689 g/cm^3, F（000） = 530, μ（MoKa） = 0.699 mm^-1, R = 0.0366 and wR = 0.0810. Compound 1 contains one- dimensional chains which are further stacked through π-π interactions to form a 3D supramolecular architecture. The water molecule O（1W） is involved in hydrogen bonding interactions with symmetric carboxylate oxygen atom 0（4） at （x＋ 1, y＋1, z） and symmetric PZDC nitrogen atom N（6） at （1-x, 1-y, 1-z）, which completes the structure of 1. Magnetic susceptibility measurement indicates that the compound behaves a weak antiferromagnetic exchange interaction.

Crystal Structure and Theoretical Studies of Tetrahytrate(1-H-1,2,4-triazole-3,5-dicarboxylicacid)nickel

A new compound, [Ni（Hdctrz）（H2O）4]（1, H3dctrz = 1-H-1,2,4-triazole-3,5-dicarboxylic acid）, has been successfully synthesized via slow evaporation. The structure of 1 was characterized by FT-IR, elemental analysis and single-crystal X-ray diffraction. Compound 1 crystallizes in monoclinic, space group P21/c with a = 6.871（1）, b = 11.468（1）, c = 12.178（1） A, b = 101.291（1）o, V = 941.01（16） A3, Z = 4, C4H9N3O8Ni, Mr = 285.85, Dc = 2.018 g·cm–3, m = 2.10 mm–1, F（000） = 584, GOOF = 1.025, the final R = 0.0515 and wR = 0.2125 for 1404 observed reflections（I 〉 2s（I））. The crystal structure is assembled by a slightly distorted {NiNO5} octahedral geometry and hydrogen bonds viz. N–H…O, O–H…O, C–O…π and π···π weak interactions. A rare π···π interaction from triazolate and carboxylate is affirmed through the molecular orbitals（MO） of three adjacent Ni CN molecules. The 3D Hirshfeld surface analysis was employed to gain additional insight into the interactions responsible for the packing of compound 1. Quantitative examination of 2D fingerprint plots revealed, amongst others, the dominating participation of O···H, N···H and π···π interactions in the molecular packing.

Synthesis,Crystal Structure and Theoretical Calculations of a Zinc(Ⅱ) Coordination Polymer Assembled by Pyrazine-2,3-dicarboxylic Acid and Bis(imidazol) Ligands

A new metal-organic coordination polymer [Zn（pzdc）（mbix）]n·nH2O（H2pzdc = pyrazine-2,3- dicarboxylic acid, mbix = 1,3-bis（imidazol-1-ylmethyl）-benzene） 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. Yellow crystals crystallize in monoclinic system, space group P21/n with a = 8.5519（6）, b = 14.8764（10）, c = 16.4108（11） A, β = 103.4520（10）o, V = 2030.5（2）A^3, C（20）H（18）N6O5Zn, Mr = 487.77, Dc = 1.596 g/cm^3, F（000） = 1000, Z = 4, μ（MoK α） = 1.257 mm^-1, the final R = 0.0260 and w R = 0.0706 for 3445 observed reflections（I 〉 2σ（I））. The structure of 1 exhibits a one-dimensional chain-like structure. In addition, natural bond orbital（NBO） analysis was performed by the PBE0/LANL2DZ method in Gaussian 03 Program. The calculation results show obvious covalent interaction between the coordinated atoms and Zn（Ⅱ） ion.

A Lanthanide-transition Metal Coordination Polymer:{[CuEu(Hbidc)_2(H_2O)_4]·H_2O}_n(H_3bidc=1H-benzimidazole-5,6-dicarboxylic Acid)

The title complex 1,{[CuEu（Hbidc）2（H2O）4]·H2O}n（H3bidc = 1H-benzimidazole-5,6-dicarboxylic acid）,has been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in triclinic,space group P1,with a = 7.791（2）,b = 12.058（3）,c = 12.109（3）,α = 82.189（5）,β = 72.407（5）,γ = 89.184（4）°,V = 1073.7（5）3,C18H18CuEuN4O13,Mr = 713.86,Dc = 2.208 g/cm3,μ（MoKα） = 3.967 mm-1,F（000） = 700,GOOF = 0.950,Z = 2,the final R = 0.0531 and wR = 0.1068 for I 2σ（I）.Complex 1 possess a tape-like chain structure consisting of Eu2C8O4 and Cu2Eu2C18N4O4 metallic rings alternatively arranged and is the first 3d-4f heterometallic complex based on the 1H-ben-zimidazole-5,6-dicarboxylato ligand（Hbidc）.Plenty of hydrogen-bonding and π...π stacking interactions connect the 1D chains to construct a 3D supramolecular architecture.

A Benzimidazole-pyridine-2,3-dicarboxylic Acid Bridged Zinc(Ⅱ)Coordination Complex–crystal Structure,Quantum Chemistry and Luminescence

The structure of a zinc（Ⅱ） coordination complex（1）, [C14 H10 N3 O5 Zn1.5]n or [Zn1.5（bzim）（pydc）（H2 O）]n（H2 pydc = pyridine-2,3-dicarboxylic acid, Hbzim = benzimidazole）, has been determined by X-ray crystallography and characterized by elemental analysis, IR spectrum and luminescence. Chemical formula： C14 H10 N3 O5 Zn1.5. It crystallizes in the monoclinic system, space group P21/c with a = 12.303（4）, b = 12.052（4）, c = 10.212（3） ？, β = 104.147（4）, V = 1468.3（8） ？3, Z = 4, Mr = 398.30, Dc = 1.802 g/cm3, F（000） = 800, μ = 2.501 mm-1 and S = 1.000. The 2-D network architecture of 1 is constructed from benzimidazole, zinc and pyridine-2,3-dicarboxylic acid. The quantum-chemical calculations have been performed on ‘molecular fragments’ extracted from the crystal structure using the B3 LYP method in Gaussian 09. The luminescence spectrum shows that complex 1 emits blue luminescence.

Synthesis of 3 or 4-Substituted Pyridine-2, 6-Dicarboxylic Acid

Various 4-alkoxypyridine-2, 6-dicarboxylic acids were synthesized starting from 2, 6- lutidine. Through aldol condensation and Michael addition, various 4-arylpyridine-2, 6-dicarboxylic acids were synthesized starting from aromatic aldehydes and 2-acetylfuran.

Synthesis and Crystal Structure of Palladium(Ⅱ) Complex with 2,2’-Bipyridine-3,3’-dicarboxylic Acid

The title complex Pd（H2BDA）Cl2·2DMSO （C16H14Cl2N2O6PdS2, H2BDA = 2,2＇- bipyridine-3,3＇-dicarboxylic acid） has been synthesized and characterized by IR spectra, elemental analysis and ^1H NMR spectra. Its structure was determined by single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic system, space group P2（1/c） with a = 1.3604（6）, b = 1.2606（6）, c = 1.3521 （6） nm, β = 103.677（7）°, V = 2.2530（17） nm^3, Mr = 571.75, Z = 4, Dc = 1.686 g/cm^3,μ = 1.280 mm^-1, F（000） = 1136, R= 0.0405 and wR= 0.0908. The complex presents a planar quadrangle arrangement and is assembled via hydrogen bonds.