2,2′-Bipyridine-Modified Tamoxifen: A Versatile Vector for Molybdacarboranes

Investigations on the antitumor activity of metallacarboranes are sparse in the literature and limited to a handful of ruthena- and molybdacarboranes. In this study, the molybdacarborane fragment [3-(CO)₂-closo-3,1,2-MoC₂B₉H₁₁] was combined with a vector molecule, inspired by the well-known drug tamoxifen or 4,4′-dihydroxytamoxifen (TAM-diOH). The molybdacarborane derivative [3,3-{4-[1,1-bis(4-hydroxyphenyl)but-1-en-2-yl]-2,2′-bipyridine-κ²N,N′}-3-(CO)₂-closo-3,1,2-MoC₂B₉H₁₁] ( 10 ), as well as the ligand itself 4-[1,1-bis(4-hydroxyphenyl)but-1-en-2-yl]-2,2′-bipyridine ( 6 ) showed cytotoxic activities in the low micromolar range against breast adenocarcinoma (MDA-MB-231, MDA-MB-361 and MCF-7), human glioblastoma (LN-229) and human glioma (U-251) cell lines. In addition, compounds 6 and 10 were found to induce senescence and cytodestructive autophagy, lower ROS/RNS levels, but only the molybdacarborane 10 induced a strong increase of nitric oxide (NO) concentration in the MCF-7 cells.     

Synthesis of 2,2′-bithiophene-5,5′-tetrahydroisoquinoline as michellamine analogs

Atropisomers of 2,2′-bithiophene-5-tetrahydroisoquinoline, S -8, R -8, and 2,2′-bithiophene-5,5′-tetrahydroisoquinoline, (S,S)-11, (R,S)-11, (R,R)-11, analogs of michellamines have been synthesized in low yield under Stille coupling conditions (Pd⁰-mediated cross coupling reactions) of stannanes 1 or 2 with non-racemic bromotetrahydroisoquinoline 6. The use of non-racemic iodotetrahydroisoquinoline 7 instead of 6 significantly improves the efficiency of the coupling, affording the atropisomers in moderate yields.     

Electrochemical copolymerization of carbazole and 2,2′:5′-2″ terthiophene: characterization and micro-capacitor application

In this paper, a copolymer of carbazole (Cz) and 2,2′:5′,2″-terthiophene (TTh) was electropolymerized in 0.1 M sodium perchlorate (NaClO₄)/acetonitrile (CH₃CN) on glassy carbon electrode. The optimum conditions of resulting homopolymers of Cz, TTh and copolymer of Cz and TTh in the initial feed ratio of [Cz]₀/[TTh]₀ = 1/10 were characterized by cyclic voltammetry, Fourier-transform infrared-attenuated total reflectance, scanning electron microscopy, energy dispersive X-ray analysis, and electrochemical impedance spectroscopy. Morphological analysis of copolymer shows that a micro-spherical and web-like morphology was formed for copolymer at different initial feed ratios of [Cz]₀/[TTh]₀ = 1/2, 1/5 and 1/10. The capacitive behavior of the modified electrodes was defined via Nyquist, Bode-magnitude, and Bode-phase plots. The highest low-frequency capacitance (C _LF) was obtained as 4.11 mFcm^?2 in the initial feed ratio of [Cz]₀/[TTh]₀ = 1/10. Double-layer capacitance (C _dl) and phase angles (θ) were obtained for homopolymer and copolymer systems. The highest C _dl was obtained as 2.01 mFcm^?2 for the copolymer in the initial feed ratio of [Cz]₀/[TTh]₀ = 1/2. The highest phase angle of copolymer was obtained as θ = ~75° in the initial feed ratio of [Cz]₀/[TTh]₀ = 1/1. These capacitance results confirmed that films of copolymer Cz/TTh are promising materials for micro-capacitor applications.     

Metal complexes of diaryl and 2,2′-dipyridyl disulfides

The variable transformations of the S?S bond in the presence of metal complexes generally depend upon the different reaction conditions used. In this review, the synthesis and coordination versatility of complexes derived from diaryl and 2,2′ -dipyridyl disulfide have been discussed in the absence or presence of other donor groups.     

A 3D Mesomeric Supramolecular Structure of a Cu(II) Coordination Polymer with 1,1′-Biphenyl-2,2′,3,3′-tetracarboxylic Acid and 5,5′-Dimethyl-2,2′-bipyridine Ligands

A novel metal–organic framework {[Cu(H₂bptc)(cbpy)(H₂O)]·(H₂O)} _n (1) has been hydrothermally synthesized through reaction of 1,1′-biphenyl-2,2′,3,3′-tetracarboxylic acid (H₄bptc) with Cu(II) salt in the presence of ancillary nitrogen ligand 5,5′-dimethyl-2,2′-bipyridine (cbpy), and its structure was determined by X-ray diffraction and characterized by elemental analysis, and IR spectrum. The title compound crystallizes in monoclinic space group P2₁/c. Both right- and left-handed helices are detected in the structure. In the ab-plane, adjacent chains are homochiral and parallel to each other, which are connected together by hydrogen bonds to form a 2D supramolecular structure. The supramolecular layers with opposite chirality are arranged alternatively along the c-axis to form a 3D mesomeric supramolecular structure through π···π interactions. The thermal stability of the complex 1 was studied by thermal gravimetric and differential thermal analysis.     

New Diamides of 2,2′-dipyridyl-6,6′-dicarboxylic Acid for Actinide-Lanthanide Separation

The extraction of americium and lanthanides by diamides of 2,2′-dipyridyl-6,6′-dicarboxilic acid solutions in polar diluents was investigated. The dependence of extraction properties of the diamides on their structure was studied and the distribution ratios of americium and lanthanides from nitric acid solutions were determined. The highest extraction was found for the compounds with the ethyl-group and the alkyl-substituted aryl-group on the amidic nitrogen. The Am/Ln separation factors higher than 10 were achieved for extraction from high acidity media.     

Nickel complex-mediated copolymerization of regioisomeric 5,5′-bis(chlorobenzoyl)-2,2′-dimethoxybiphenyls: synthesis of wholly aromatic copolyketones

Aromatic coupling copolymerization of 5,5^′-bis(4-chlorobenzoyl)-2,2^′-dimethoxybiphenyl (1) and 5,5^′-bis(3-chlorobenzoyl)-2,2^′-dimethoxybiphenyl (2) has successfully afforded higher-molecular-weight polyketones than either of the corresponding homopolymerizations. The wholly aromatic copolyketones thus obtained have highly amorphous nature with high glass transition temperatures (T_g).     

Free Catalyzed Synthesis of 2,2′-Bipyridine via Ozonolysis Technique

The ozonation of a triple bond in organic compounds is rare in industry. The reaction is much more complicated to run, because ozone is an electrophilic agent and more likely to bind to the double bond compared to the triple bond in an organic compound. This may be a problem because some fine organic substances are very hard to synthesize and can only be solved by the ozonolysis technique of a triple-bond organic compound. In addition, oxidation by using ozone is also preferred because of the cleanliness and effectiveness of the reaction. A novel method for the synthesis of 2,2?-bipyridine was described, which involves ozonolysis of a 2-ethynylpyridine and is supported by a high-pressure reactor. The reaction proceeds via ozone attack on the acetylenic triple bond, cleavage, and free radical formation. The present study establishes the conditions for selective ozonolysis of 2-ethynylpyridine, leading to 2,2?-bipyridine. The 2,2?-bipyridine was characterized by gas chromatography flame ionization detector (GC-FID) and mass spectroscopy techniques. A novel suggested mechanism was used to explain the oxidation process. Analysis showed that the formation of oxidized product is shown when ozone is supplied in excess, which shows that the reaction between 2-ethynylpyridine and ozone is a first-order reaction, whe reby the result of the relationship only depends on the concentration of the starting material, which is 2-ethynylpyridine acts as the limiting reactant.     

First example of a CLICK reaction of a coordinated 4′-azido-2,2′:6′,2″-terpyridine ligand

The first example of a copper-catalysed [2 + 3] cycloaddition reaction of a coordinated 4′-azido-2,2′:6′,2″-terpyridine ligand is reported and the solid state structures of the precursor and product are described.     

Experimental Investigation of Poly-β-Hydroxybutyrate Production by Azohydromonas lata: Kinetics and Artificial Neural Network Modeling

Batch culture of Azohydromonas lata was investigated for the production of intracellular poly-β-hydroxybutyrate (PHB). In order to determine the C:N value of the culture media for maximizing the microbial productivity of PHB, different concentrations of glucose and ammonium chloride were used as carbon and nitrogen sources, respectively. The optimal temperature and shaking rate was obtained at 30°C and 180 rpm, respectively. The maximum intracellular PHB concentration obtained was 5.09 g/l, which was 20% (w/w) of the cell dry weight (CDW) after 72 h. Also, the synthesis of PHB was growth associated with the C:N ratio of 153.71. The maximum calculated Y_p/s was 0.212 (gr/gr) and the specific production rate value after 12 h was 0.264 g/l/h, with 40 and 50 g/l of glucose concentrations, respectively, with 0.5 g/l ammonium chloride kept constant. The chemical composition of the resulting PHB was analyzed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The Leudeking–Piret model was used for kinetic analysis of the PHB production, the statistical analysis of which was modeled by response surface methodology. An artificial neural network technique was applied for modeling of the microbial production of PHB by A. lata as a function of the glucose concentration and CDW, where the minimum mean square error of the model was 0.0012 and 0.0038 for glucose concentrations of 50 g/l and 40 g/l, respectively, when 0.5 g/l ammonium chloride was kept constant.     

Non-isothermal degradation kinetics of poly (2,2′-dihydroxybiphenyl)

Catalytic oxidative polymerization of 2,2′-dihydroxybiphenyl (DHBP) was performed by using Schiff base polymer-Cu (II) complex and hydrogen peroxide as catalyst and oxidant, respectively. According to size exclusion chromatography (SEC) analysis, the number-average molecular weight (M _n), weight-average molecular weight (M _w) and polydispersity index (PDI) values of poly (2,2′-dihydroxybiphenyl) (PDHBP) were found to be 37,500, 90,000 g mol⁻¹ and 2.4, respectively. The thermal degradation kinetics was investigated by thermogravimetric analysis in dynamic nitrogen atmosphere at four different heating rates: 5, 10, 15 and 20 °C min⁻¹. The derivative thermogravimetry curves of PDHBP showed that its thermal degradation process had one weight-loss step. The apparent activation energies of thermal decomposition for PDHBP as determined by Tang, Flynn–Wall–Ozawa (FWO), Kissenger–Akahira–Sunose (KAS), Coats–Redfern (CR) and Invariant kinetic parameter (IKP) methods were 109.1, 109.0, 110.0, 108.4 and 109.8 kJ mol⁻¹, respectively. The mechanism function and pre-exponential factor were determined by master plots and Criado–Malek–Ortega method. The most likely decomposition process was a D _n Deceleration type in terms of the CR, master plots and Criado–Malek–Ortega results.     

Oxidation of alkylbenzenes catalyzed by polymer-bound 2,2′-bipyridine-iron complexes

Polymer-bound 2,2′-bipyridine-iron complexes were synthesized and found to be novel catalysts for the oxidation of saturated hydrocarbons. Toluene, p-xylene, ethylbenzene, n-propylbenzene and n-butylbenzene were oxidized under an atmosphere of air or oxygen in the absence of solvent at 110°C in the presence of the iron complexes chemically immobillized on polymers, affording corresponding ketones and alcohols in most cases. Except for toluene, the conversion of alkylbenzene was 20% to 35% with the different iron complexes: The selectivity in producing ketone and alcohol in the oxidation of PhR (where R = Et, n-propyl and n-butyl was ∼100%.     

Investigation of the Thermal Decomposition Kinetics of Chalcopyrite Ore Concentrate usıng Thermogravimetric Data

The kinetics of the thermal decomposition of chalcopyrite concentrate was investigated by means of thermal analysis techniques, Thermogravimetry/Derivative thermogravimetry (TG/DTG) under ambient air conditions in the temperature range of 0–900°C with heating rates of 2, 5, 10, 15, and 20°C min^?1. TG and DTG measurements showed that the thermal behavior of chalcopyrite concentrate shows a two-step decomposition. The decomposition mechanism was confirmed using X-ray diffraction (XRD), Scanning Electron Microscope (SEM)/energy-dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR) analyses. Kinetic parameters were determined from the TG and DTG curves for steps I and II by using two model-free (isoconversional) methods—Flyn–Wall–Ozowa (FWO) and Kissinger–Akahira–Sunose (KAS). The kinetic parameters consisting of E_a, A, and g(α) models of the materials were determined. The average activation energies (E_a) obtained from both models for the decomposition of chalcopyrite concentrate were 72.55 and 300.77 kJ mol^?1 and the pre-exponential factors (A) were 15.07 and 29.39 for steps I and II, respectively. The most probable kinetic model for the decomposition of chalcopyrite concentrate is an first-order mechanism, i.e., chemical reaction [g(α) = (?ln(1?α))], and an Avrami–Eroeyev equation mechanism, i.e., nucleation and growth for n = 2 [g(α) = (?ln(1?α)^1/2)], for steps I and II, respectively.     

2,2′,6,6′-四氯双酚A的合成研究

概述了２,２′,６,６′－四氯双酚Ａ的应用和合成工艺。详细研究了双酚Ａ在二氯乙烷溶剂中经氯化反应合成２,２′,６,６′－四氯双酚Ａ,得到了最佳合成工艺条件,收率可达９１５％,为工业化生产提供了可靠的基础数据     

Kinetics and Selectivity of the Fischer–Tropsch Synthesis: A Literature Review

A critical review of the kinetics and selectivity of the Fischer–Tropsch synthesis (FTS) is given. The focus is on reaction mechanisms and kinetics of the water–gas shift and Fischer–Tropsch (FT) reactions. New developments in the product selectivity as well as the overall kinetics are reviewed. It is concluded that the development of rate equations for the FTS should be based on realistic mechanistic schemes. Qualitatively, there is agreement that the product distribution is affected by the occurrence of secondary reactions (hydrogenation, isomerization, reinsertion, and hydrogenolysis). At high CO and H₂O pressures, the most important secondary reaction is readsorption of olefins, resulting in initiation of chain growth processes. Secondary hydrogenation of α-olefins may occur and depends on the catalytic system and the process conditions. The rates of the secondary reactions increase exponentially with chain length. Much controversy exists about whether these chain-length dependencies stem from differences in physisorption, solubility, or diffusivity. Preferential physisorption of longer hydrocarbons and increase of the solubility with chain length influences the product distribution and results in a decreasing olefin-to-paraffin ratio with increasing chain length. Process development and reactor design should be based on reliable kinetic expressions and detailed selectivity models.     

A novel double-helical-chain coordination polymer constructed from 2,2′-biphenyldicarboxylate-linked binuclear-copper motif

The first 1-D double-helical-chain coordination polymer, [(H₂O)Cu(BPDC)] (2,2^′-biphenyldicarboxylate), based upon the binuclear square pyramidal copper(II)-pair motifs has been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction technique. [(H₂O)Cu(BPDC)] crystallized in orthorhombic crystal system, space group Cmca with unit cell dimensions a=21.073(6) Å, b=7.118(2) Å and c=17.670(5) Å, Z=8.     

Aldehyde-decorated 2,2′-bipyridine and 2,2′:6′,2″-terpyridine ruthenium(II) complexes: Convenient scaffolds for supramolecular chemistry

Two new aldehyde-decorated tpy and bpy-containing ruthenium(II) complexes, [Ru(1)(bpy)₂][PF₆]₂ and [Ru(1)(tpy)Cl][PF₆] in which 1 is 5,5′-bis(4-formylphenyl)-2,2′-bipyridine, have been prepared and fully characterized. The packing in both solid state structures involves extensive O_aldehyde···HC_pyridine contacts, but π-stacking interactions are important only between [Ru(1)(tpy)Cl]⁺ cations.     

Investigation of 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone-based catalyst in the reaction of liquid-phase oxidation of inorganic sulfides

In this paper, the intermediate and final reaction products of catalytic oxidation of inorganic sulfides in the presence of oxygen dissolved in the kerosene fraction and 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone were investigated. The thiosulfate and sulfate are major products of the oxidation of sodium sulfide under these conditions. The intermediate and final products in the catalytic oxidation of sulfide sulfur do not affect the rate of its oxidation. The yield of catalytic oxidation products depends on the nature of the sulfide and on the pH of the solution. The catalytic cycle for sulfide oxidation in the presence of 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone is shown. The role of 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone is to create a new and a more effective way of electron transfer from the reducing agent (sulfide) to the oxidant (oxygen).