Search

Eight new ruthenium complexes (C1, C2 (Ru-benzene or Ru-toluene complexes with L1, 3-amino-2-chloropyridine); C3, C4 (Ru-benzene or Ru-toluene complexes with L2, 2-amino-5-chloropyridine); C5, C6 (Ru-benzene or Ru-toluene complexes with L3, 3-acetylpyridine); and C7, C8 (Ru-benzene or Ru-toluene complexes with L4, 4-acetylpyridine) were synthesized. The chemical structures and purity of the compounds were confirmed using standard analytical methods such as 1H,13C NMR and IR spectroscopy, mass spectrometry, and elemental analysis, and their electrochemical behavior was evaluated using cyclic voltammetry experiments. The stability of the compounds in dimethyl sulfoxide solution was confirmed using 1H NMR spectroscopy. Finally, the antimicrobial potential of two complex precursors (CP1, [Ru(η6-benzene)Cl(μ-Cl)]2 and CP2, [Ru(η6-toluene)Cl(μ-Cl)]2), four ligands (L1–L4), and eight corresponding complexes (C1–C8) was screened against nine pathogenic microorganisms and two reference bacterial strains using the micro-well dilution method. The highest antibacterial activity (0.63 mg/mL) was for C5 against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Salmonella enteritidis, while C8 displayed more pronounced antimicrobial activity against Candida albicans (MIC/MMC = 0.31 mg/mL). Subsequently, the studied complexes underwent a detailed examination utilizing the DFT methodology, acquiring important quantum-chemical descriptors. Notably, the HOMO-LUMO gap was established as a significant correlate with the antimicrobial activity of synthesized compounds. [ABSTRACT FROM AUTHOR]

The title compound, C15H12BN3, is a type of diazaborinane featuring substitution at 1, 2, and 3 positions in the nitrogen–boron six-membered heterocycle. It is comprised of two almost planar units, the pyridyl ring and the Bdan (dan = 1,8-diaminonaphtho) group, which subtend a dihedral angle of 24.57 (5)°. In the crystal, the molecules are linked into R44(28) hydrogen-bonding networks around the fourfold inversion axis, giving cyclic tetramers. The molecules form columnar stacks along the c axis.

[Display omitted] • Gordonia rubripertincta ZJJ is a novel isolate for 3-MP degradation. • The v max , K m and K i values were 0.48 h−1, 88.3 mg L−1 and 924 mg L−1, respectively. • C and N released from 3-MP was mainly converted to CO 2 (67.4%) and NH 4 + (36.3%). • Three possible metabolic pathways were proposed for 3-MP degradation by strain ZJJ. Methylpyridines are a class of highly toxic pyridine derivatives. In this study, a novel degrading bacterium was isolated for 3-methylpyridine (3-MP) degradation (Gordonia rubripertincta ZJJ, GenBank accession NO. OP430847.1; CCTCC M 2022975). The maximum specific degradation rate, half-saturation constant and inhibition constant were fitted to be 0.48 h−1, 88.3 mg L−1 and 924.0 mg L−1, respectively. During 3-MP biodegradation, the lost total organic carbon was transformed into CO 2 (67.4 %) and biomass (32.6 %), and ammonia nitrogen was almost the sole inorganic species with a conversion rate of 36.3 %. Three metabolic pathways were possibly involved in 3-MP degradation: I) methyl oxidation followed by ring hydroxylation and hydrogenation; II) rupture of C=C and C–N bonds after ring reduction; III) initial ring hydroxylation. The study not only provides a novel strain for the high-efficient degradation of 3-MP, but also contributes to an in-depth understanding of 3-MP biotransformation. [ABSTRACT FROM AUTHOR]

Ovarian cancer is the second leading cause of death of female gynecological malignant tumor patients worldwide. Although surgery and chemotherapy have achieved dramatic achievement, the mortality remains high, resulting in the demand for new specific drug discovery. Disrupting ovarian cancer growth via histone deacetylase (HDAC) inhibition is a strategy for cancer therapy or prevention. In this work, we synthesized a novel pyridine derivative named compound H42 and investigated its anti-cancer activity in vivo and in vitro. We found that compound H42 inhibited ovarian cancer cell proliferation with IC50 values of 0.87 µM (SKOV3) and 5.4 µM (A2780). Further studies confirmed that compound H42 induced apoptosis, intracellular ROS production, and DNA damage. Moreover, compound H42 downregulated the expression of histone deacetylase 6 (HDAC6) with a distinct increase in the acetylation of a-tubulin and heat shock protein 90 (HSP90), followed by the degradation of cyclin D1, resulting in cell cycle arrest at the G0/G1 phase. Importantly, ectopic expression of HDAC6 induced deacetylation of HSP90 and a-tubulin, while HDAC6 knockdown upregulated the acetylation of HSP90 and a-tubulin. However, in the nude xenograft mouse study, compound H42 treatment can inhibit ovarian cancer growth without obvious toxicity. These findings indicated that compound H42 inhibited ovarian cancer cell proliferation through inducing cell cycle arrest at the G0/G1 phase via regulating HDAC6-mediated acetylation, suggesting compound H42 could serve as a lead compound for further development of ovarian cancer therapeutic agents. [ABSTRACT FROM AUTHOR]

The synthesis of pyridine derivatives is an active area of research in the development of new drugs. In view of the above importance, a novel compound with fused rings of derivatives of biologically active imidazole, pyridine and chromanone was synthesized. The crystal structure was analysed by single crystal X-ray diffraction method. The quantum chemical parameters of the molecule in the gaseous state were calculated by semi-empirical method using restricted Hartree-Fock wavefunction. The physicochemical properties such as druglikeness and bioactive scores were predicted to understand the drug transport and receptor interactions. Molecular docking studies were performed to analyze the binding of this compound with various bacterial and fungal pathogens. This study points out the potential of this compound to act as an antimicrobial agent. Comparison with related compounds shows that the addition of more number of biologically active groups enhances the activity.

• Oxidized graphene was modified by lignin and pyridine derivatives. • Inspired by mimosa, a long-term anti-corrosion composite coating was prepared. • Pyridine group and Fe2+ had a strong binding energy (-369.99 kcal/mol). Although the coating can effectively prevent metal corrosion, it is easy to form micro-pores and micro-cracks during the curing process, and the coating is inevitably damaged by the external environment during use, resulting in a reduction in its protective ability, thereby shortening the service life of the substrate. Inspired by the stress closure function of mimosa, an intelligent anti-corrosion coating with stress closure function against corrosion products (Fe2+) was prepared by using pyridine derivatives and lignin grafted graphene oxide (ATGO). By density functional theory calculation, the binding energy of pyridine group and Fe2+ was −369.99 kcal/mol, and their strong complexation would facilitate the formation of a dense protective layer at the metal corrosion interface. The test results showed that ATGO-CM coating had high fracture strength (86.9 MPa) and adhesion strength (2.03 MPa), as well as low water vapor permeability (1.3 × 10-6 g m−1 day−1 Pa−1). Electrochemical testing denoted that after soaking in 3.5 wt% saline solution for 100 days, the impedance modulus of the ATGO-CM coating remained at 5.36 × 109 Ω·cm2 at low frequencies (f = 0.01 Hz), which was two orders of magnitude higher than the blank group. Through scratch experiments showed that the complexation effect of pyridine groups and corrosive products could significantly improve the corrosion resistance of the coating, with R ct value of 1.8 × 104 Ω cm2 for the damaged coating, one order of magnitude higher than the blank group. This work not only provided a reference for the preparation of intelligent anti-corrosion coatings with bionic functions, but also increased the added value of biomass materials. [ABSTRACT FROM AUTHOR]

In the title hydrated salt, [Ni(C21H17F2N3)2](NO3)2·2H2O, the central NiII ion is coordinated by six N atoms from two tridentate chelating 2,6-bis[(E)-(4-fluorobenzylimino)methyl]pyridine ligands. While the central NiII ion is six-coordinate, its environment is distorted from an octahedral structure because of the unequal Ni—N distances. The Ni—N bond lengths vary from 1.8642 (14) to 2.2131 (15) Å, while the N—Ni—N angles range from 79.98 (6) to 104.44 (6)°. Three coordinating sites of each chelating agent are almost coplanar with respect to the pyridine ring, and two pyridine moieties are perpendicular to each other. Two non-coordinating nitrate anions within the asymmetric unit balance the charges of the central metal ion, and are linked with two crystal water molecules, forming a water–nitrate cyclic tetrameric unit [O...O = 2.813 (2) to 3.062 (2) Å]. In an isolated molecule, the fluorophenyl rings of one ligand are stacked with the central ring of the other ligand via π–π interactions, with the closest centroid-to-plane distances being 3.359 (6), 3.408 (5), 3.757 (6) and 3.659 (5) Å.

Three new organic ligands and six new corresponding complexes with Zinc(II) were synthesized. In order to evaluate the biological activity of the synthesized compounds, ligands and corresponding complexes were tested against LN229 and U87 cell lines. [Display omitted] The newly synthesized ligands based on pyrazine and pyridine derivatives and its Zn (II) complexes were reported. Elemental analysis (EA), flame atomic absorption spectroscopy (F-AAS), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), single-crystal X-ray and electron diffraction were used for the characterisation. The antimicrobial and antifungal activity of all the synthesized compounds was tested against Gram-positive bacteria, Gram-negative bacteria, and yeasts. Besides that, the anticancer nature of the studied compounds was also evaluated. The MTT test showed different results on the cytotoxicity of the ligands. Ligand L 3 did not show toxicity after 24-hour incubation but its complex had some toxic effects on both glioblastoma cell lines. Although the obtained Zn(L 3)Cl 2 did not show the same activity against cancer cells as cisplatin, the studied complex proved to be less toxic against normal cells than the standard drug. Due to this, the further biological studies, such as cell apoptosis assay and DNA double-strand breaks (DSBs) were performed on this pair of compounds. [ABSTRACT FROM AUTHOR]

The first nickelacarborane with closo-nido structure [10′,11′-(Py)2-3,9′-Ni(1,2-C2B9H11)(7′,8′-C2B8H8)] was isolated from the reaction of nickel(IV) bis(dicarbollide) with pyridine. The molecular structure of this complex was determined by single crystal X-ray diffraction. The nickel atom is a common vertex for the closo-NiC2B9 cluster and the nido-NC2B8 cluster where it is located together with carbon atoms in the open NiC2B2 pentagonal face. It is assumed that its formation proceeds through the nucleophile-induced removal of the B(6)H vertex followed by rearrangement of the forming 11-vertex cluster, which most likely proceeds through a sequence of closing and opening reactions.

Summary: Cellular senescence is a state of irreversible cell growth arrest. Increasing evidence suggests that cellular senescence contribute to tumour suppression in vivo. However, only a few anti‐cancer drugs have been discovered to induce cellular senescence. Searching for new compounds which can inhibit cancer cell growth by inducing senescence is becoming one of the most attractive research fields. To test the effects of candidate compounds on cancer cell growth, cell proliferation assays, senescence‐associated β‐galactosidase (SA‐β‐gal) staining, and flow cytometry assay were performed. Immunofluorescence, western blot, and qRT‐PCR experiments were used to further study the molecular mechanisms of the candidate compounds. We demonstrated that a pyridine derivative, 4‐(4‐fluorophenyl)‐2‐phenyl‐5, 6, 7, 8‐tetrahydroquinoline (FPTHQ), from a pool of 46 compounds can induce senescence of ovarian cancer cells in a dose‐dependent manner. FPTHQ caused growth inhibition by inducing G0/G1 cell cycle arrest in A2780 cells. Increased activities of SA‐β‐gal were observed in FPTHQ‐treated A2780, OVCAR‐3 and SKOV‐3 cell lines. In addition, FPTHQ treatment increased the protein levels of MMP3 and the mRNA levels of IL‐6 and IL‐8 in A2780 cells, indicating the appearance of senescence‐associated secretary phenotype (SASP) in the cells. Furthermore, we found that p21 was up‐regulated and DNA damage was accumulated in FPTHQ‐treated ovarian cancer cells. So far, our data suggest that FPTHQ can induce senescence in multiple ovarian cancer cell lines through activation of p21 signalling pathway by causing excessive DNA damage. [ABSTRACT FROM AUTHOR]

In this article, novel pyridine-based polyurethane urea elastomers were synthesized from 1,6-hexamethylene diisocyanate and poly(tetramethylene oxide) glycol of molecular weight 1400 which was chain extended with 3,4-diaminopyridine. These new heterocyclic polyurethane urea elastomers were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and static mechanical measurements as a function of pyridine moieties content and the crosslinkers structure from the hard domains. This settlement of the amine groups on the pyridine rings realizes weak intermolecular hydrogen bonds compared with other pyridine derivatives studied by us. The molecular dynamics and local relaxation of these polyurethane urea elastomers were investigated using broadband dielectric spectroscopy. Results show that pyridine content slightly increases the glass transition temperature and has low dielectric strength of the segmental relaxation as a result of weaker cohesive domains. [ABSTRACT FROM AUTHOR]

The phytochemical investigation of Houttuynia cordata Thunb. led to the isolation of nine alkaloids (1 ‒ 9). Based on the NMR spectroscopic data interpretation and comparison with the literature values, the structures of the isolates were characterized and subdivided into two aporphines (1 and 2), two aristolactams (3 and 4), four benzamides (5–8), and one pyridine derivative (9). To the best of our knowledge, this is the first report on the isolation of compound 6 (N-benzoyl tyramine) from the family Saururaceae and compound 9 (2,3-dihydroxy-4-(hydroxymethyl)-tetrahydrofuran-l-yl]pyridine-4,5-diol) from plant origin. All the above research results contributed to consolidating the chemotaxonomic knowledge of H. cordata. [Display omitted] • Nine alkaloids were isolated from Houttuynia cordata Thunb. whole plant. • Compounds 6 and 9 were first time isolated from the family Saururaceae. • Compounds 8 and 9 are markers to distinguish H. cordata and other plant species. • The chemotaxonomic homogeneity of H. cordata with other species was concluded. [ABSTRACT FROM AUTHOR]

4,6-Bis(4-chlorophenyl)-2-oxo-1,2-dihydropyridine-3-carbonitrile (L) reacted with Mn(II), Fe(III), Co(II) and Ni(II) in methanol and acetone as a solvent at room temperature to form a new solid complexes. The isolated complexes were characterized by elemental analysis, magnetic properties, conductance measurements, mass, IR, UV-Vis and 1H NMR spectroscopic methods and thermal analyses. The thermogravimetric and infrared spectroscopic data confirmed the presence of water in the composition of the complexes and the ligand reacted as a bidentate. The metal – ligand binding in metal complexes is predicted using density functional theory. The ligand and their metal complexes were also evaluated for their antibacterial activity. The complexes showed high activities compared with free ligand. DOI: http://dx.doi.org/10.4314/bcse.v29i1.7

Three new metal complexes of 4,6-bis(4-chlorophenyl)-2-amino-1,2-dihydropyridine-3-carbinitrile (L) with Co(II), Ni(II) and Cu(II) were synthesized and characterized with physicochemical and spectroscopic techniques. The data suggest that (L) acts as a bidentate ligand bound to the divalent metal ions through amino N and carbinitrile N atoms having [M(L)(HO)] formula (M = metal ions). The theoretical parameters, model structures, charges and molecular orbitals of all possible complexes have been determined using density functional theory. The energy gap of free ligand is ∆ E = 0.12565 eV, and this value is greater than energy gap of complexes, which indicates that the complexes are more reactive than free ligand. Also, ∆ E of Co(II) complex is lower than other complexes, which indicates that Co(II) complex is more reactive than Ni(II) and Cu(II) complexes. The antibacterial and antifungal activities of the ligand, metal salts and its complexes were tested against some microorganisms (bacteria and fungi). The complexes showed increased antibacterial and antifungal profile in comparison with the free ligand. [ABSTRACT FROM AUTHOR]

In the title compound, C13H10N2O5, the dihedral angle between the pyridine and phenyl ring is 50.47 (2)°. The hydroxyl H and ketone O atoms form an intramolecular O—H...O hydrogen bond with the hydroxyl group almost coplanar with the phenyl ring. In the crystal, molecules are linked by two C—H...O hydrogen bonds, forming dimers. The dimers are linked by further C—H...O hydrogen bonds, forming a three-dimensional architecture.

In this study, three new organic ligands N′-(benzylidene)-6-chloropyrazine-2-carbohydrazonamide (L 1), 6-chloro-N′-(4-nitrobenzylidene)picolinohydrazonamide(L 2), and N′-(benzylidene)-4-chloropicolinohydrazonamide (L 3) and three copper coordination compounds (Cu(L 1)Cl 2 , Cu(L 2)Cl 2 and Cu(L 3)Cl 2) based on them were synthesized. All obtained compounds were characterized using appropriate analytical techniques: elemental analysis (EA), thermogravimetric analysis (TG–DTG), Fourier transform infrared spectroscopy (FTIR) and flame-atomic absorption spectrometry (F-AAS). These methods of physicochemical analyses helped to assume that the complexation in three cases proceeds in a bidentate manner. The X-ray investigation confirmed the synthesis pathway and molecular structures for L 1 and L 3 ligands. The antimicrobial activity of the obtained compounds was then comprehensively investigated, where Cu(L 3)Cl 2 showed the strongest antibacterial properties against all tested bacteria (Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli). LN229 human glioma cells and BJ human normal fibroblasts cells were treated with tested compounds and their cytotoxicity was evaluated with MTT test. The effect of complexing on antitumor activity has been investigated. The ligand L 1 and its complex showed similar activity against normal cells while complexation increases toxicity against cancer cells in concentrations of 50 and 100 μM. For the one pair of ligand/complex compounds the apoptosis detection, cell cycle analysis and gene expression analysis (qRT-PCR) were performed. Cu(L 1)Cl 2 showed the stronger toxic effect in comparison with L 1 due to the population of early apoptotic cells which revealed metabolic activity in MTT assay. Three new organic ligands and three new corresponding complexes with copper(II) were synthesized. In order to evaluate the biological activity of the synthesized compounds, ligands and corresponding complexes were tested against cancer cell lines. [Display omitted] • Three new organic ligands and three copper coordination compounds were synthesized; • The X-ray investigation confirmed the molecular structures for L 1 and L 3 ligands; • Cu(L 3)Cl 2 showed the significant antibacterial properties; • Compounds L 1 and Cu(L 1)Cl 2 showed selective activity against LN229 cancer cells. [ABSTRACT FROM AUTHOR]

The development of coordination complexes to activate hydrogen peroxide (H 2 O 2 ) selectively is a goal that has long been pursued. As highly reactive intermediates, the high-valent metal-oxo species play important roles in many biological and industrial catalytic oxidation processes. To improve the catalytic efficiency of metal complexes, the peroxide O O bond should be cleaved heterolytically to decrease the decomposition of H 2 O 2 into O 2 and H 2 O. In this work, we provide a simple method to obtain coordination complex catalysts based on iminodiacetic acid (IDA), copper(II) ions and pyridine derivatives. Catalytic activity tests showed that the introduction of 4-aminopyridine ligands resulted in an enhanced catalytic activity of the IDA/Cu(II)/4-ampy complex. A series of designed experiments proved that high-valent copper-oxo species ([ O Cu III (IDA)(4-ampy) 2 ] species) were formed in the IDA/Cu(II)/4-ampy complex system in the presence of hydrogen peroxide. The [ O Cu III (IDA)(4-ampy) 2 ] species were detected by in-situ high-definition electrospray ionization mass spectrometry, and has been considered as the possible active species during H 2 O 2 activation catalyzed by the IDA/Cu(II)/4-ampy complex (with the molar ratio of IDA/Cu(II)/4-ampy being greater than 1:1:2). A mechanism has been proposed based on the results of electron paramagnetic resonance and density functional theory calculations. [ABSTRACT FROM AUTHOR]

Two dinuclear copper(II) complexes, [LCu(μ-Cl)Cl]2(DMF) (1) and [LCu(μ-Br)Br]2(2), with the bidentate ligandN-(pyridin-2-ylmethyl)cyclohexanamine, L, were synthesized and characterized by physicochemical and spectroscopic (IR, UV–vis) data. The crystal structural analysis of1shows that both copper(II) ions are in a distorted square pyramidal N2Cl3environment with the apical position of the copper(II) being occupied by the bridging chloride anion which is equatorial to the other copper ion, forming a dimeric copper(II) complex. The chromotropic properties of both complexes, including solvato-, thermo-, and halochromism, were investigated. The complexes show reversible thermochromism in solution which is irreversible in the solid state. It was found that the solvatochromism is due to structural change followed by solvation of the vacant sites of the complexes. Their halochromic properties were studied in pH range of 1–11 by visible absorption spectroscopy. The color changes from blue to green and to colorless are due to deprotonation and protonation of the ligands. [ABSTRACT FROM PUBLISHER]

A series of novel substituted pyridine derivatives have been synthesized via the reaction of 3-indole carboxaldehyde with 3-aminoacetophenone. The products structures have been elucidated from elemental analysis as well as IR, H NMR, C NMR, and MS spectroscopy data. All the synthesized compounds have shown anticancer activity against HEPG2 and MCF-7 in vitro; some of them have exhibited the in vivo activity. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, C6H5Cl2NO2S, contains two molecules with similar conformations (r.m.s. overlay fit for the non-H atoms = 0.067 Å). Atoms attached to the pendent Csp3—S bond are arranged in a staggered conformation with one of the Cl atoms anti to the C atom in the aromatic ring [C—S—C—Cl torsion angles = 178.41 (11) and −176.70 (13)°]. In the crystal, molecules are linked by C—H...N and C—H...O hydrogen bonds, generating a three-dimensional network, and weak aromatic π–π stacking is also observed [centroid–centroid separation = 3.8902 (17) Å].

[Display omitted] Ruthenium-based anticancer agents have created a center of attention in the field of inorganic medicinal chemistry. The first fully characterized cationic ruthenium(II)-arene complexes [Ru(η6-p- cymene) (PAr 3)LNCl]+ with highly lipophilic PAr 3 ligands where Ar = 3,5-((CH 3) 3 C) 2 C 6 H 3 – (L1), 3,5-(CH 3) 2 C 6 H 3 – (L2), 4-CH 3 O-3,5-(CH 3) 2 C 6 H 2 – (L3) and 4-CH 3 O-C 6 H 4 – (L4) with N = 3-methylpyridine (1 – 4 , respectively), or L4 and 4-methylpyridine (5), or L4 and CH 3 CN (6) were obtained (yields 67–91%) as solids stable to light and air. Electrical conductance indicates that all the complexes are 1:1 electrolytes in solution. Their composition and purity have been unambiguously established by single-crystal X-ray diffraction, NMR spectroscopy and elemental analysis. The coordination geometries are uniform for all six complexes and each structure consist of a unipositive complex cation bearing the phosphine ligands L1 - L4 and LN = 3-methylpyridine, 4-methylpyridine or CH 3 CN attached to the organometallic fragment. The equivalent unit cell volumes per formula unit decrease with 1 > 3 > 2 > 4 > 5 > 6 , accurately reflecting the decreasing sizes of the phosphines L1 - L4 , and a greater occupied volume for 3-methyl- vs. 4-methylpyridine, and the smallest volume contribution from CH 3 CN. Electrochemical studies showed mixed electrochemical mechanisms (EC/ECE) from partial substitution of p -cymene by CH 3 CN ligands from the solvent. A large electrochemical stability window (>2.2 V) for Ru(II) was observed extending beyond the physiological E° range. The complexes were cytotoxic against human cancer cell lines in vitro , and some complexes altered cell morphology. [ABSTRACT FROM AUTHOR]

4,6-Bis(4-chlorophenyl)-2-oxo-1,2-dihydropyridine-3-carbonitrile (L) reacted with Mn(II), Fe(III), Co(II) and Ni(II) in methanol and acetone as a solvent at room temperature to form a new solid complexes. The isolated complexes were characterized by elemental analysis, magnetic properties, conductance measurements, mass, IR, UV-Vis and 1H NMR spectroscopic methods and thermal analyses. The thermogravimetric and infrared spectroscopic data confirmed the presence of water in the composition of the complexes and the ligand reacted as a bidentate. The metal - ligand binding in metal complexes is predicted using density functional theory. The ligand and their metal complexes were also evaluated for their antibacterial activity. The complexes showed high activities compared with free ligand. [ABSTRACT FROM AUTHOR]

Abstract: A series of new multi-ferrocenyl substituted pyridine derivatives, 4,6-diferrocenyl-3,5-diferrocenylethynyl-2-methylpyridine (1), 3,6-diferrocenyl-4,5-diferrocenylethynyl-2-phenylpyridine (2), 4,6-diferrocenyl-3,5-diferrocenylethynyl-2-phenylpyridine (3), 3,5-diferrocenyl-4,6-diferrocenylethynyl-2-phenylpyridine (4) were synthesized by dicarbonylcyclopentadienylcobalt mediated [2+2+2] cycloaddition reaction. The molecular composition and structure of compounds 1–4 were characterized by FT-IR, NMR, MS, CV and Elemental analysis. The molecular and crystal structure of compound 1 was determined by X-ray single crystal diffraction analysis. The cyclic voltammetry and square wave voltammetry highlight the electrochemical behaviors of compounds 1–4, which indicates multi-step reversible redox processes of ferrocenyl moieties have occurred. The wave splitting and ΔE 1/2 (oxidation potential difference) values of 1–4 were carefully analyzed, which reveals that the interactions between the ferrocenyl units of 1–4 are related to their molecular structures. The molecular structures of isomers 2–4 have been identified by their electrochemical properties and spectroscopic information. [Copyright &y& Elsevier]

Highlights: [•] Pyridine derivative was covalently bonded to chitosan through a sequence of four reactions. [•] The synthesized biopolymer has the ability to textile dye removal from aqueous solutions. [•] Dye hydrophobic properties favor the structural adjust to the synthesized biopolymer structure. [•] The kinetic data fitted to non-linear regression of pseudo-second-order in a chemisorption process. [ABSTRACT FROM AUTHOR]

Abstract: This work presents a new method to analyse simultaneously by GC–MS 31 pesticides from different chemical classes (2,4 D, 2,4 MCPA, alphacypermethrin, bifenthrin, bromoxynil, buprofezin, carbaryl, carbofuran, clopyralid, cyprodinil, deltamethrin dicamba, dichlobenil, dichlorprop, diflufenican, diuron, fenoxaprop, flazasulfuron, fluroxypyr, ioxynil, isoxaben, mecoprop-P, myclobutanil, oryzalin, oxadiazon, picloram, tau-fluvalinate tebuconazole, triclopyr, trifluralin and trinexapac-p-ethyl). This GC–MS method will be applied to the analysis of passive samplers (Tenax® tubes and SPME fiber) used for the evaluation of the indoor and outdoor atmospheric contamination by non-agricultural pesticides. The method involves a derivatisation step for thermo-labile or polar pesticides. Different agents were tested and MtBSTFA (N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide), a sylilation agent producing very specific fragments [M−57], was retained. However, diuron could not be derivatised and the isocyanate product was used for identification and quantification. Pesticides which did not need a derivatisation step were not affected by the presence of the derivatisation agent and they could easily be analysed in mixture with derivatised pesticides. The method can be coupled to a thermal-desorption unit or to SPME extraction for a multiresidue analysis of various pesticides in atmospheric samples. [Copyright &y& Elsevier]

A new series of acyclic aromatic polyamide pyridine derivatives a-h and a new macrocyclic polyamide containing pyridine ring i were synthesized by the reaction of N2, N6-bis (2-aminoethyl) pyridine-2, 6-dicarboxamide or N2, N5-bis (3-aminopropyl) pyridine-2, 6-dicarboxamide with various acyl chloride. The compounds were characterized by MS,1H NMR, IR and elemental analysis. The single-crystal structure of g confirmed that the crystal is of triclinic, space group P-1 with M r=487.55, a=9.303 1(19), b=12.167(2), c=126.50(3) nm, α=108.91(3)o, β=97.57(3)o, γ=102.07(3)o, V=1 293.5 nm, Z=2, D c=1. 252 kg/m3, μ=0.086 mm−1, F(000)=516. X-ray analysis reveals that there exist hydrogen bonding and network structure in the crystal. [ABSTRACT FROM AUTHOR]

Abstract: The title complexes, {[Ag(Pepy)(NO3)]}∞ (1) and [HPepy(FeCl4)] (2) (Pepy= trans-2-(2-phenylethyleneyl)pyridine), had been synthesized and characterized structurally by single-crystal X-ray diffraction analysis, FTIR as well as thermal analysis. The geometrical structure of complex 1 is a one-dimensional helical zigzag chain. Each AgI center is five-coordinated by two anions and one Pepy ligand while the anion is an uncommon tetra-dentate coordinating to two AgI by O atoms, respectively. The anions connecting with AgI as bridge blocks resulted in the formation of crystalline of helical polymeric chain. In the mononuclear complex 2, the FeIII center is four-coordinated by four Cl− as [FeCl4]− anion, which connected with hydrogen atoms from the protonated N atom and the C atoms from HPepy+ to form multivalent hydrogen bonded network through N–H⋯Cl and C–H⋯Cl interactions. The two frameworks can be both considered as a 3D structure driven by diverse hydrogen bonds as well as π–π stacking interactions. [Copyright &y& Elsevier]

Self-assembling behavior of N , N ′-didodecyl-3,5-pyridinedicarboxamide and its silver complex has been studied. They act as gelators in solution and gelate a variety of organic solvents. Though the silver complex exhibits lower gelation abilities for halogenated and aromatic solvents, long-term stability is achieved for ethanol and acetone gels. Moreover, the silver complex exhibits a smectic A phase on cooling while a single component of N , N ′-didodecyl-3,5-pyridinedicarboxamide exhibits no mesomorphic behavior. The XRD pattern for the complex shows that the layer spacing of the S A phase is 37 Å. [ABSTRACT FROM AUTHOR]

Based on prior work, we hypothesized that cigarette smoke contains chemicals that can inhibit growth of the chick chorioallantoic membrane (CAM). In this study, gas chromatography and mass spectrometry were used to identify 12 pyridine derivatives in the inhibitory fractions of smoke eluted from solid phase extraction cartridges. These pyridine derivatives were further studied individually in dose response experiments to determine their effects on CAM growth. A correlation was observed between the functional group substitutions on pyridine and the relative toxicity of each pyridine derivative. In the CAM growth assay, pyridine derivatives with single methyl or single ethyl substitutions had lowest observed adverse effect levels (LOAELs) of 5 × 10−9 and 5 × 10−12 M, respectively. Other pyridine derivatives and pyridine itself had LOAELs in the micromolar range. One of the most inhibitory derivatives, 3-ethylpyridine, was studied further and inhibited cell proliferation, as measured by BrdU incorporation. Since 3-ethylpyridine inhibited growth at picomolar doses and is added to consumer products including cosmetics, food, drinks, and tobacco, it will be important to perform further toxicological testing to determine its effect on human health. [ABSTRACT FROM PUBLISHER]

The hydrolyis or the aquation reactions of compounds of the types cis- and trans-Pt(Ypy)[sub 2] (NO[sub 3] )[sub 2] (Ypy = pyridine derivative) were studied in D[sub 2] O and characterized by multinuclear ([sup 195] Pt, [sup 13] C, and [sup 1] H) NMR spectroscopy. In acidic pD, the product of the cis complexes is cis-[Pt(Ypy)[sub 2] (D[sub 2] O)[sub 2] ][sup 2+] , whereas in basic medium cis-Pt(Ypy)[sub 2] (OD)[sub 2] is formed. The [sup 195] Pt NMR resonances of the products containing ligands with an ortho substituent were observed at lower fields than the other complexes. The average coupling constant ([sup 3] J([sup 195] Pt–[sup 1] H) and [sup 3] J([sup 195] Pt–[sup 13] C)) is 44 Hz for the diaqua species and 42 Hz for the dihydroxo compounds. At neutral pD, several hydrolyzed species were observed, except for the 2-picoline and 2,4-lutidine complexes, which contained only one compound, cis-[Pt(Ypy)[sub 2] (D[sub 2] O)(OD)][sup +] . The other hydrolyzed products for the ligands with no ortho substituent were identified as the dihydroxo-bridged dimer, the monohydroxo-bridged dimer, the trimer, and possibly the tetramer. The trans analogues have shown two signals in acidic pD corresponding to the diaqua monomer and the monohydroxo-bridged aqua dimer. Two species (the dihydroxo compound and the monohydroxo-bridged hydroxo dimer) were also observed in basic pD. In neutral medium, a third signal assigned to a longer chain hydroxo-bridged oligomer or polymer was detected.Key words: platinum, pyridine derivative, nitrato, hydrolysis, NMR, aquation.Les réactions d'aquation et d'hydrolyse des complexes de types cis- et trans-Pt(Ypy)[sub 2] (NO[sub 3] )[sub 2] (Ypy = dérivé de la pyridine) ont été étudiées dans D[sub 2] O et les produits ont été caractérisés par résonance magnétique multinucléaire ([sup 195] Pt, [sup 13] C et [sup 1] H). En milieu acide, le produit des complexes cis est cis-[Pt(Ypy)[sub 2] (D[sub 2] O)[sub 2] ][sup 2+] , tandis que cis-Pt(Ypy)[sub 2] (OD)[sub 2] est formé en milieu basique. Les signaux en RMN du [sup 195] Pt des complexes contenant des ligands substitués en position ortho ont été observés à plus bas champ que les autres. Les constantes de couplage moyennes [sup 3] J([sup 195] Pt–[sup 1] H) et [sup 3] J([sup 195] Pt–[sup 13] C) sont 44 Hz pour les espèces diaqua et 42 Hz pour les composés dihydroxo. À pD neutre, plusieurs espèces hydrolysées ont été observées, excepté pour les complexes contenant 2-picoline et 2,4-lutidine, qui ont montré une seule espèce, cis-[Pt(Ypy)[sub 2] (D[sub 2] O)(OD)][sup +] . Les autres produits hydrolysés pour les complexes contenant des ligands sans substituent ortho ont été identifiés comme le dimère à double ponts-hydroxo, le dimère à simple pont-hydroxo, le trimère et probablement le tétramère. Les composés analogues trans ont montré deux signaux à pD acide, correspondant au monomère diaqua et au dimère aqua à pont-hydroxo. Deux espèces (le composé dihydroxo et le dimère hydroxo à pont-hydroxo) ont aussi été observées en milieu basique. À pD neutre, un troisième signal attribué à un oligomère ou polymère à pont-hydroxo a été détecté.Mots clés : platine, pyridine, nitrato, hydrolyse, RMN, aquation. [ABSTRACT FROM AUTHOR]

A series of novel gelators (GB 1 , GB 2 and GB 3) based on pyridine derivatives with various numbers of benzene unit from 1 to 3 were designed and synthesized. They exhibited obvious aggregation-induced emission properties. The self-assembly processes of GB 1 , GB 2 and GB 3 in DMSO or mixed solvent of DMSO/H 2 O (4/1, v/v) were investigated. Hydrogen bonding and π-π stacking interaction were the main driving force for gel formation. Very interestingly, the gelation ability, self-assembly mode, rheological behavior and surface wettability of these self-assembly systems could be tuned by the number of benzene unit. With the increasing number of benzene unit, the solubility of the molecule was obviously enhanced in organic solvent, and then the formation of gel needs higher ratio of H 2 O in mixed solvents. J-type aggregation mode was employed in gels GB 1 and GB 2. Microbelts and micron blocks structure were formed in their self-assembly gels. Gel GB 1 in DMSO showed the strongest mechanical strength comparing with other gels GB 2 and GB 3 in mixed solvents due to the firmest hydrogen bonding interaction. The hydrophobic surface with the contact angles from 138° to144.5° were obtained in self-assembly system. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of a tetradentate ligand, 2,2′-(pyridin-2-ylmethylazanediyl)diethanethiol (H2L), with dodecacarbonyltriiron in dry toluene leads to the formations of a hexacarbonyl complex, [Fe2(EDT)(CO)6] (EDT=ethylenedithiolate), 1a, which is fully characterised. The formation of this complex is via intramolecular C–S/N bonds formation/cleavage promoted by iron-sulfur coordination chemistry. A possible mechanism for the C–S/N bonds formation/cleavage in the formation of the complex is proposed. [Copyright &y& Elsevier]

• 3-Cyano-2-(ethylamino)-4,6-dimethyl pyridine was synthesized by a new procedure. • The synthesized compound is good fluorophore. • Estimation of cilazapril in the dosage forms and patient plasma. An efficient method for the synthesis of 3-cyano-2-(ethylamino)-4,6-dimethylpyridine was developed. The structures of the synthesized compound were confirmed by elemental analysis and spectral data. The synthesized reagent has good fluorescence intensity at 381 nm after excitation at 334 nm. This fluorophore was utilized for the analysis of the antihypertensive drug, cilazapril. Cilazapril exhibited quenching of the fluorescence of the organic reagent. The method was successfully applied for the analysis of cilazapril in dosage form, spiked human plasma and urine with mean percentage recoveries of 99.94 ± 1.17, 99.71 ± 1.91 and 100.06 ± 1.46 respectively. The method was also extended for in vivo analysis of cilazapril in plasma. The maximum plasma level was picked after two hours and it was found to be 280 ng/mL. [ABSTRACT FROM AUTHOR]

The first nickelacarborane with closo-nido structure [10′,11′-(Py)2-3,9′-Ni(1,2-C2B9H11)(7′,8′-C2B8H8)] was isolated from the reaction of nickel(IV) bis(dicarbollide) with pyridine. The molecular structure of this complex was determined by single crystal X-ray diffraction. The nickel atom is a common vertex for the closo-NiC2B9 cluster and the nido-NC2B8 cluster where it is located together with carbon atoms in the open NiC2B2 pentagonal face. It is assumed that its formation proceeds through the nucleophile-induced removal of the B(6)H vertex followed by rearrangement of the forming 11-vertex cluster, which most likely proceeds through a sequence of closing and opening reactions. [ABSTRACT FROM AUTHOR]

New nickel(II) compounds, viz. trans- [Ni(LHAQ) 2 (Py) 2 ·C 6 H 6 (1), cis- [Ni(LHAQ) 2 (3-MePy) 2 (2), cis- [Ni(L2−MeAQ) 2 (3-MePy) 2 (3), trans- [Ni(L4−MeAQ) 2 (Py) 2 ·C 6 H 6 (4), trans- [Ni(L4−OMeAQ) 2 (Py) 2 ·C 6 H 6 (5), trans- [Ni(L4−OEtAQ) 2 (Py) 2 ·C 6 H 6 (6), trans- [Ni(L4−BrAQ) 2 (Py) 2 ·C 6 H 6 (7) and trans- [Ni(L4−ClAQ) 2 (3-MePy) 2 ·2(3-MePy) (8) (primary ligands: LXAQ = substituted 5-[(E)-2-(aryl)-1-diazenyl]quinolin-8-olate; secondary ligands: Py = pyridine or 3-MePy = 3-methylpyridine) have been synthesized and characterized by elemental analysis, IR, UV–vis spectroscopy. The magnetic susceptibilities of the compounds were also measured. Single-crystal X-ray diffraction analysis of the compounds revealed octahedral geometries with trans configurations for 1 , 4 – 8 and cis configurations for 2 and 3. The occurrence of intramolecular Ni⋅⋅⋅H pyridine interactions in 2 and in 3 , may account for additional stabilization of their assemblies at least in the solid state. The effective magnetic moment (μ eff) in the range 3.02–3.40 BM agree with the expected values for octahedral Ni(II) cations with two unpaired electrons. Ni(II) compounds were also screened for their antimicrobial activity. Distorted octahedral nickel(II) complexes with trans - and cis -configurations were synthesized, and their properties and applications are reported. Image 1 • Eight new nickel(II) compounds with distorted octahedral geometries have been synthesized. • Structural characterizations of the compounds were accomplished from single crystal X-ray crystallography and magnetic measurements. • Compounds were screened for antibacterial activity. [ABSTRACT FROM AUTHOR]