Reaction Of Bis Research Articles

Research of Interaction Processes of Fast and Thermal Neutrons with Solution of Organic Dye Methyl Orange

The emergence of powerful sources of ionizing radiation, the needs of nuclear energy, technology and medicine, as well as the need to develop reliable methods of protection against the harmful effects of penetrating radiation stimulated the development of such branches of science as radiation chemistry, radiation biology, radiation medicine. When an organic dye solution is exposed to ionizing radiation, it irreversibly changes color. As a result, the absorbed dose can be determined. The processes of interaction of neutron fluxes with an aqueous solution of an organic dye methyl orange (МО) – C14H14N3О3SNa, containing and not containing 4% boric acid, have been investigated. The work was carried out on a LINAC LUE-300 at NSC KIPT. A set of tungsten plates was used as a neutron-generating target. The electron energy was 15 MeV, the average current was 20 μA. The samples were located behind the lead shield and without it, with and without a moderator. Using the GEANT4 toolkit code for this experiment, neutron fluxes and their energy spectra were calculated at the location of experimental samples without a moderator and with a moderator of different thickness (1-5 cm). An analysis of the experimental results showed that when objects without lead shielding and without a moderator are irradiated, the dye molecules are completely destroyed. In the presence of lead protection, 10% destruction of the dye molecules was observed. When a five-centimeter polyethylene moderator was installed behind the lead shield, the destruction of dye molecules without boric acid on thermal neutrons was practically not observed. When the fluxes of thermal and epithermal neutrons interacted with a dye solution containing 4% boric acid, 30% destruction of dye molecules was observed due to the exothermic reaction 10B (n, α). The research has shown that solutions of organic dyes are a good material for creating detectors for recording fluxes of thermal and epithermal neutrons. Such detectors can be used for radioecological monitoring of the environment, in nuclear power engineering and nuclear medicine, and in the field of neutron capture therapy research in particular.

Synthesis, reactivity and transition metal complexes of 1,1′-bis(diethynylphosphino)ferrocene

The synthesis, oxidation reactions and transition metal complexes of a new ferrocenyl-bisphosphine, [Fe{C5H4P(C≡CH)2}2] (1), are described. The reaction of bis(dichlorophosphino)ferrocene with four equivalents of ethynylmagnesium bromide resulted in the formation of 1 in 76% yield. The reaction between 1, aqueous H2O2 or elemental sulphur produced bis(oxide) and bis(sulfide) derivatives, [Fe{C5H4P(E)(C≡CH)2}2] (2 E = O, 3 E = S). Reaction of 1 with [Ru(η 6-p-cymene)Cl2]2 yielded a diruthenium complex [Fe{C5H4P(C≡CH)2}2{RuCl2(η 6-p-cymene)}2] (4). Treatment of 1 with [M(COD)Cl2] (M = Pd, Pt) resulted in [Fe{C5H4P(C≡CH)2}2{MCl2}] (5 M = Pd, 6 M = Pt). Equimolar reactions between 1 and CuX produced binuclear complexes, [Fe{C5H4P(C≡CH)2}2{CuX}2] (7 X = Cl, 8 X = Br, 9 X = I).

Experimental validation of an integrated modelling approach to neutron emission studies at JET

An integrated modelling methodology for the calculation of realistic plasma neutron sources for the JET tokamak has been developed. The computational chain comprises TRANSP plasma transport and DRESS neutron spectrum calculations, and their coupling to the MCNP neutron transport code, bridging plasma physics and neutronics. In the paper we apply the developed methodology to the analysis of neutron emission properties of deuterium and helium plasmas at JET, and validate individual modelling steps against neutron diagnostic measurements. Two types of JET discharges are modelled—baseline-like and three-ion radio-frequency scenarios—due to their diversity in plasma heating, characteristics of the induced fast ion population, and the imprint of these on neutron emission properties. The neutron emission modelling results are quantitatively compared to the total neutron yield from fission chambers, neutron emissivity profiles from the neutron camera, neutron spectra from the time-of-flight spectrometer, and neutron activation measurements. The agreement between measured and calculated quantities is found to be satisfactory for all four diagnostic systems within the estimated experimental and computational uncertainties. Additionally, the effect of neutrons not originating from the dominating D(D, n)3He reactions is studied through modelling of triton burnup DT neutrons, and, in mixed D-3He plasmas, neutrons produced in the 9Be(D, nγ)10B reaction on impurities. It is found that these reactions can contribute up to several percent to the total neutron yield and dominate the neutron activation of samples. The effect of MeV-range fast ions on the neutron activation of 115In and 27Al samples is measured and computationally validated.

N,N-Bis(4′-(hexyloxy)-[1,1′-biphenyl]-4-yl)thiophen-2-amine

N,N-Diarylthiophen-2-amine units are of great interest for the synthesis of optoelectronic devices. In this communication, N,N-bis (4′-(hexyloxy)-[1,1′-biphenyl]-4-yl)thiophen-2-amine was obtained by means of a Buchwald–Hartwig cross-coupling reaction of bis(4′-(hexyloxy)-[1,1′-biphenyl]-4-yl)amine and 2-bromothiophene in the presence of tris(dibenzylideneacetone)dipalladium(0), tri-tert-butyl phosphine and sodium tert-butanolate. The structure of newly synthesized compounds was established by means of elemental analysis, high-resolution mass spectrometry, 1H, 13C NMR, IR and UV spectroscopy and mass-spectrometry.

SYNTHESIS, SPECTRAL CHARACTERIZATION AND ANTIMICROBIAL ACTIVITIES OF BIS(CYCLOPENTADIENYL)TITANIUM(IV) COMPLEXES WITH SCHIFF BASES DERIVED FROM5-(SUBSTITUTED ARYL)-2-HYDRAZINO-1, 3, 4-OXADIAZOLE AND INDOLINE-2, 3-DIONE

Titanium(IV) complexes of type[(η5-C5H5)2TiCl(L)] have been synthesized by the reactions of bis(cyclopentadienyl)titanium(IV)dichloride with Schiff bases (LH) derived by the condensation of 5-(substituted aryl)-2-hydrazino-1,3,4-oxadiazole and indoline-2,3-dione in tetrahydrofuranin the presence oftriethylamine. All these complexes are soluble in PhNO2, DMF and DMSO.The complexes were characterized by elemental analyses, electrical conductance, magnetic susceptibility, UV-Vis, IR, 1H NMR, 13C NMR, XRD and SEM spectral techniques. Low molar conductance values indicate that they are non-electrolytes. The spectral data indicate5-coordinate geometry for the complexes.XRD pattern indicate that the complexes have monoclinic crystal system and particle sizes were found 49.36 nm (nano-size). In vitro antifungal activity of synthesized compounds was evaluated against fungi Aspergillusniger, Aspergillusflavus,ColletotrichumfalcatumandIn vitro antibacterial activity was determined by screening the compounds against gram negative (P. aeruginosa, S.typhi) and gram positive (S. aureus and B.subtilis) bacterial strains using minimum inhibition concentration method (MIC) by serial dilution technique. The titanocene(IV) complexes have higher antimicrobial effect than the parent Schiff bases.

Conjugation of Phenylboronic Acid Moiety through Multistep Organic Transformations on Nanodiamond Surface for an Anticancer Nanodrug for Boron Neutron Capture Therapy

Abstract Detonation nanodiamonds (DNDs) have attracted considerable attention, in particular, in the field of nanomedicine due to their biocompatibility as well as various functionalities imparted by surface modification. Meanwhile, boron neutron capture therapy (BNCT) is an advanced cancer treatment utilizing nuclear fission reaction of 10B upon neutron irradiation. Recently, quite a few boron-containing nanoparticles have been investigated to deliver 10B atoms into cancer tissue selectively and retentively. In this study, we explored boronic acid functionalized DNDs as an anticancer agent for BNCT. Phenylboronic acid (PBA) moiety was introduced to polyglycerol (PG) modified DNDs (DND-PG) through multistep organic transformation, giving percent order of boron atoms. The process is scalable and reliable by simple covalent chemistry and the resulting product is well dispersed, and stable chemically and physically under physiological conditions. In the in vivo experiments, the resulting material was accumulated in the tumor to exert BNCT efficacy upon neutron irradiation. These results demonstrate that the PBA functionalized DNDs are a promising candidate as an anticancer nanodrug for BNCT.

Simulation method for measurement of the cross-section of the 14N(n, α)11B reaction using a gridded ionization chamber

Simulation method for measurement of the cross-section of the 14N(n, α)11B reaction using a gridded ionization chamber

Influence of the amine donor on hybrid guanidine-stabilized Bis(μ-oxido) dicopper(III) complexes and their tyrosinase-like oxygenation activity towards polycyclic aromatic alcohols

The tyrosinase-like activity of hybrid guanidine-stabilized bis(μ-oxido) dicopper(III) complexes [Cu2(μ-O)2(L)2](X)2 (L = 2-{2-((Diethylamino)methyl)phenyl}-1,1,3,3-tetramethylguanidine (TMGbenzNEt2, L2) and 2-{2-((Di-isopropylamino)methyl)phenyl}-1,1,3,3-tetramethylguanidine (TMGbenzNiPr2, L3); X = PF6−, BF4−, CF3SO3−) is described. New aromatic hybrid guanidine amine ligands were developed with varying amine donor function. Their copper(I) complexes were analyzed towards their ability to activate dioxygen in the presence of different weakly coordinating anions. The resulting bis(μ-oxido) species were characterized at low temperatures by UV/Vis and resonance Raman spectroscopy, cryo-ESI mass spectrometry and density functional theory calculations. Small structural changes in the ligand sphere were found to influence the characteristic ligand-to-metal charge transfer (LMCT) features of the bis(μ-oxido) species, correlating a redshift in the UV/Vis spectrum with weaker N-donor function of the ligand. DFT calculations elucidated the influence of the steric and electronic properties of the bis(μ-oxido) species leading to a higher twist of the Cu2O2 plane against the CuN2 plane and a stretching of the Cu2O2 core. Despite their moderate stability at −100 °C, the bis(μ-oxido) complexes exhibited a remarkable activity in catalytic oxygenation reactions of polycyclic aromatic alcohols. Further the selectivity of the catalyst in the hydroxylation reactions of challenging phenolic substrates is not changed despite an increasing shield of the reactive bis(μ-oxido) core. The generated quinones were found to form exclusively bent phenazines, providing a promising strategy to access tailored phenazine derivatives.

Synthesis, Characterization, and Catalytic Study of Amine-Bridged Bis(phenolato) Co(II) and Co(II/III)-M(I) Complexes (M = K or Na).

Co(II) complexes 1-3 bearing amine-bridged bis(phenolato) complexes have been synthesized through reactions of bis(phenols) with CoCl2 or Co(OAc)2. Oxidation of the Co(II) complex with air resulted in partial oxidation, generating mixed valence Co(II/III) complexes 4 and 5. In addition, due to the presence of alkali compounds (KOAc and NaOMe), 4 and 5 formed as Co-alkali metal heterometallic complexes, which are the first example of mixed valence Co(II/III)-M(I) (M = K or Na) complexes. Complexes 1-5 showed good activity in the cycloaddition of epoxides and CO2 under atmospheric pressure, generating cyclic carbonates in 40-99% yields. Co(II/III)-Na(I) complex 5 performed better in reactions of bulkier substrates, underlining the enhanced activity of mixed valence Co-alkali metal heterometallic complexes. On the contrary, complex 5 showed limited activity in copolymerization of epoxide and CO2.

Evaluation of temporal behavior of 200 keV proton components of intense pulsed ion beam with prompt gamma- and time-of-flight spectrometry

The paper demonstrates that temporal behavior of proton components of intense pulsed ion beams accelerated to average energy of up to 200 keV with number of 1015 per shot can be reliably evaluated with use of prompt γ-spectrometry. The ion shots are dumped onto a pyrolytic h-BN plate in which a 5 mm diameter hole is provided to enable simultaneous time-of-flight measurement of the ion species with a Biased Ion Collector. The proton energy and number are determined by simultaneous control of signals from two organic scintillators shielded with lead layers of 2 and 3 cm to evaluate contributions of the nuclear reactions 10B(p, αγ)7Be and 11B(p, γ)12C via measurement of yields of prompt γ-rays with energies of 429 and 4439 keV, respectively.

Syntheses, structures and fluorescence properties of two Ce/Zn-Ce complexes with an open-chain ether Schiff base ligand

Reaction of bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine (H2L) with Ce(NO3)3 afforded a new Ce(III) complex with composition [Ce(H2L)(NO3)3] (1). Complex 1 reacts with zinc acetate and terephthalic acid to prepare complex 2, [Zn4Ce2(L)4(terephthalate)2][Ce(DMF)(NO3)5]. They have been characterized by elemental analysis, UV/Vis and IR spectroscopy, and single-crystal X-ray diffraction. The structure analysis revealed that 1 is mononuclear, whereas 2 is d-f heteronuclear. The fluorescence properties of the ligand and complexes 1 and 2 were studied in the solid state. The significantly blue-shifted emissions and enhancement of fluorescence in 1 and 2 relative to the ligand were attributed to coordination of ligand with metal ions. The results show that the structure and fluorescence of the Ce(III) complexes can be modified by introducing Zn(II) ion and auxiliary ligand terephthalate.

Experimental studies for the personalized application of boron neutron capture therapy to the treatment of cutaneous melanoma

Background: Boron neutron capture therapy (BNCT) is a binary modality based on the nuclear reaction 10B (n, α) lithium-7 (7Li) that has been used to treat a variety of tumors, among these, cutaneous melanoma (CM). In previous boron biodistribution studies in agreement with the personalized oncology, we have demonstrated that boronophenylalanine (BPA) uptake can be correlated with the tumoral temperature and viability. The main aim of these studies was to evaluate the relationship between tumoral temperature and the response to the complete BNCT.

New Inorganic Boron Assessment in environmental Samples by Neutron Activation Analysis using CR-39 Solid State Nuclear Track Detectors.

A new trend in applying nuclear solid-state track detector CR-39 for neutron activation assessment of inorganic boron compounds in environmental samples was established. The nuclear reaction 10B(n, α)7Li was selected for this purpose by using gelatin film for a sample application. It possesses many advantages such as time saving, sensitivity, and reproduciblity, and many related variables were studied. Linearity was found at the range of 1.0 - 12.5 ppm and at 10.0 -250 ppm with different slopes. There were no interfering nuclei among the naturally abundant elements and their isotopes, viz. Al, O, Na, Cl, P, Ca, Si, K, and Cu. It was applied to determine boron in simulated environments and industrial soil and water samples, with recovery within the range of 96-100 %, good precision and accuracy + 1.5 - 3.0 %. The method sensitivity can be enhanced by using longer irradiation time, and few micrograms of boron can be analysed, and hence it is more suitable to be used in the activation analysis system of nuclear reactors.

Synthesis of a polyamine-modified starch flocculant and its application

A degradable flocculant was prepared by natural renewable products (starch) and a cationic polymer. A cationic polyamine polymer was prepared by reaction of bis(hexamethylene)triamine with epichlorohydrin. The influence of substrate ratio and molecular weight of cationic polymer on flocculation was investigated and the optimum molecular weight was about 4000. Polyamine-modified starch flocculant was prepared by etherification reaction of cationic polyamine polymer and corn starch. The influence of substitution degree (DS) of starch on flocculation was investigated and the maximum DS was 0.18. The structure of starch-modified flocculant was characterized by XRD and the results confirmed that the plasticized samples contained some crystalline structures that were not destroyed by the etherification reaction process and some newly formed V-type crystalline structures were mainly induced by processing. Flocculation performance was evaluated in simulated kaolin suspension and was compared with that of commercial cationic polyacrylamide (CPAM) and polyaluminium chloride (PAC) flocculants. The flocculation effects of polyamine-modified starch flocculants and commercial flocculants under different dosages and pH values were compared. The results showed that the starch-modified flocculant had the best effect and the cationic starch derivatives flocculation performance increased with increasing DS, and exhibited steady flocculation performance to kaolin suspension in the broad pH range from 4 to 10. The preparation method of starch-modified flocculant is simple in preparation process, low in production cost and pollution-free, and facilitates industrial production.

Synthesis and characterization of new highly fluorinated phosphoramidates

A one-pot synthesis of new bis(polyfluoroalkyl)dialkylaminophosphoramidates (RF(CH2)2O)2P(O)NR2 (1–6) (RF = C6F13, NR2 = NC5H10 (1), NC4H8 (2), NEt2 (3); RF = C8F17, NR2 = NC5H10 (4), NC4H8 (5), NEt2 (6)) and polyfluoroalkyl bis(dialkylamino)phosphoramidates RF(CH2)2OP(O)(NR2)2 (9–14) (RF = C6F13, NR2 = NC5H10 (9), NC4H8 (10), NEt2 (11); RF = C8F17, NR2 = NC5H10 (12), NC4H8 (13), NEt2 (14)) was performed through phosphorylation of corresponding highly fluorinated alcohols with P(O)Cl3 in dry diethyl ether followed by aminolysis. However, the former phosphoramidates (1–6) and corresponding morpholinyl derivatives 7 and 8 were alternatively prepared in better yields from phosphoramidation reaction of bis(fluoroalkyl)phosphites with amines in the presence of I2 and H2O2 in dichloromethane. All these phosphoramidates were obtained in good yields and characterized by multinuclear (1H, 13C, 31P and 19F) NMR, IR spectroscopy and HRMS.

Hantzsch reaction with bis-indole-2,3-diones: Synthesis of novel bis-spirocyclic oxindole incorporating acridine, dipyrazolo[3,4-b:4',3'-e]pyridine and pyrido[2,3-d:6,5-d']dipyrimidine

One-pot three-component cyclo-condensation reaction of bis(indole-2,3-diones) with dimedone, 3-methyl-1H-pyrazol-5(4H)-one, or 6-aminouracil in boiling acetic acid afforded bis-spirocyclic oxindoles linked to acridine, dipyrazolo[3,4-b:4',3'-e]pyridine, and pyrido[2,3-d:6,5-d']dipyrimidine, respectively.

Comparative role of the 7Li(n, γ ) reaction in Big Bang nucleosynthesis

Within the framework of the modified potential cluster model with forbidden states and their classification according to Young diagrams, the possibility of describing experimental data on the total cross sections of the neutron radiative capture on 7Li is considered. It is shown that the model used and the methods for constructing potentials make it possible to correctly describe the behavior of experimental cross sections at energies of 1 meV to 1.5 MeV, where experimental data are available. Based on the calculated total cross sections up to 5 MeV, the reaction rate is calculated and its analytical approximation is carried out. Resonance structure of 7Li(n, γ)8Li cross section and its impact on the reaction rate is examined. It is shown that the 7Li(n, γ)8Li reaction dominates at T 9 < 0.1 as opposed to the burning of 7Li in the 7Li(3H, n)9Be and 7Li(4Нe, γ)11B reactions, but comparable to (d, γ), (d, p), and (p, γ) at T 9 ∼ 1.

Time-resolved [formula omitted]-spectrometer to promptly control number and energy of protons collectively accelerated as different bunches

A two-channel γ-spectrometer with time resolution of 2.5 ns enables a prompt control of number and energy of collectively accelerated protons in their separate bunches dumped into a sustainable and refractory B4C target. The proton energy and number is determined within the range of 460 to 1600 keV and 1012–4⋅1014 per pulse, respectively, by separate measurements of yields of prompt γ-rays with energies of 429 and 2366 keV and higher, induced in the B4C targets via the nuclear reactions 10B(p, αγ)7Be, 11B(p, γ)12C and 12C(p, γ)13N, respectively. The simultaneous control of signals from two organic scintillators shielded with lead layers of 1 and 7 cm is used to reliably separate contributions of the analytical reactions. The radioactivity of 7Be and 13N radionuclides produced in the reactions is measured with a conventional HP Ge detector to calibrate the prompt technique.

Room temperature stable multitalent: highly reactive and versatile copper guanidine complexes in oxygenation reactions

Inspired by the efficiency of natural enzymes in organic transformation reactions, the development of synthetic catalysts for oxygenation and oxidation reactions under mild conditions still remains challenging. Tyrosinases serve as archetype when it comes to hydroxylation reactions involving molecular oxygen. We herein present new copper(I) guanidine halide complexes, capable of the activation of molecular oxygen at room temperature. The formation of the reactive bis(µ-oxido) dicopper(III) species and the influence of the anion are investigated by UV/Vis spectroscopy, mass spectrometry, and density functional theory. We highlight the catalytic hydroxylation activity towards diverse polycyclic aromatic alcohols under mild reaction conditions. The selective formation of reactive quinones provides a promising tool to design phenazine derivatives for medical applications.Graphic abstract

Effects of halogen ligands of complexes supported by bis(methylthioether)pyridine on catalytic activities for electrochemical and photochemical driven hydrogen evolution

Reactions of bis(methylthioether)pyridine (btep) with CuX2 (X = Br and Cl) form two new complexes, [Cu(btep)Br2] and [Cu(btep)Cl2], respectively, which have been determined by X‐ray crystallography. Both of them can serve as catalysts for electrochemical and photochemical driven hydrogen evolution. Under an overpotential (OP) of 837.6 mV, [Cu(btep)Br2] or [Cu(btep)Cl2] can electrocatalyze hydrogen evolution from a neutral water with a turnover frequency (TOF) of 373 and 120 mol of hydrogen per mole of catalyst per hour (mol H2/mol catalyst/h), respectively. Under blue light, mixing with CdS nanorods (CdS NRs) as a photosensitizer, and ascorbic acid (H2A) as a sacrificial electron donor, the photolysis of an aqueous solution (pH 4.5) with [Cu(btep)Br2] or [Cu(btep)Cl2] can provide 6180 and 5120 mol of H2 per mole of catalyst (mol of H2 (mol of cat)−1) during 48‐h irradiation with an average apparent quantum yield of 16.7% and 11.0%, respectively. The results show that [Cu(btep)Br2] shows a more efficient activity for H2 generation than [Cu(btep)Cl2]. Several electrochemical and photochemical measurements and analysis are carried out to study catalytic mechanism for H2 production.