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101.
N. S. Prostakov B. N. Anisimov A. V. Varlamov V. F. Zakharov P. I. Zakharov Chandra Mokhan Dzhkha L. A. Murugova 《Chemistry of Heterocyclic Compounds》1979,15(7):777-780
Stable diazo compounds of the azafluorene series, viz., 9-diazo-4-azafluorenone and 1,3-diphenyl-4-azafluorene, were obtained from 4-azafluorenone and 1,3-diphenyl-4-azafluorene tosylhydrazones. 1,2-Dicarbomethoxyspiro(4-azafluorene-9,3-cyclopropane) was obtained from 4-azafluorenone tosylhydrazone, and 4,5-dicarbomethoxyspiro(4-azafluorene-9,3-pyrazolenine) was obtained from 9-diazo-4-azafluorene. It is assumed that the product in the latter case is obtained as a result of reaction of a carbene, viz., 4-azafluorenylidene carbene, which is formed from 9-diazo-4-fluorene, with dimethyl acetylenedicarboxylate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 951–953, July, 1979. 相似文献
102.
A solid state copper(II) ion sensor is reported based on the application of electropolymerized undoped (neutral) polycarbazole
(PCz) and polyindole (PIn) modified electrodes. The new sensor shows high selectivity to Cu2+ ions with a detection limit of 10–5 M. PCz and PIn are formed respectively by the anodic oxidation of 50 mM carbazole and 5 mM indole monomers in dichloromethane
containing 0.1 M tetrabutylammonium perchlorate on a platinum electrode using a single compartment cell. Potentiostatic polymerization
of both the monomers are carried out at 1.3 V and 1.0 V vs. Ag/AgCl, respectively. Perchlorate ions were electrochemically
removed from the polymer films by applying – 0.2 V vs. Ag/AgCl. Polymer-coated electrodes are incubated in 1 M KCl solution
for 8 h followed by incubation in distilled water for 2 h before using as a metal ion sensor. The undoped PCz and PIn electrodes
were found to be highly selective and sensitive for Cu2+ ions with little selectivity for Pb2+ and negligible response towards Ag+, Hg2+, Cu+, Ni2+, Co2+, Fe2+, Fe3+ or Zn2+. Potentiometric responses for Cu2+ ions are recorded for both the sensor electrodes together with a double-junction Ag/AgCl reference electrode. Calibration
curves for Cu2+ are reported for both ion sensors. The polymer-modified electrodes were found to be stable for several weeks.
Electronic Publication 相似文献
103.
This work describes the results of the Cd(II) isopropylxanthate-stabilized and Mn(III) isopropylxanthate-sensitized photo-oxidation of poly(2,6-dimethyl-1,4-phenylene oxide) film in air at low temperatures (?10 to 80°). The oxidation was followed by light scattering, potassium ferri-oxalate actinometry and by measuring gel formation. The weight-average molecular weight, degree of degradation, rate of scission of links, energy of activation and quantum yield of the process depend on several factors, e.g. temperature, xanthate concentration. Various oxygen-containing groups (hydroperoxides, carbonyls, etc.) are formed in the polymer. For the determination of the content of these groups, iodometry and spectroscopy were applied. The initially present or photo-induced hydroperoxides are directly responsible for subsequent oxidative reactions which occur during 254-nm irradiation. The absorption spectra of the degraded materials in the u.v. and i.r. regions were also studied to substantiate a possible mechanism of the oxidation process. 相似文献
104.
Chandra S Gupta LK 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(4-5):1125-1130
Manganese(II), cobalt(II), nickel(II) and copper(II) complexes have been synthesized with a new tetradentate ligand viz. 1,3,7,9-tetraaza-2,4,8,10-tetraketo-6,12-diphenyl-cyclododecane (L) and characterized by the elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, 1H NMR, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMF correspond to be nonelectrolytic nature for Mn(II), Co(II) and Cu(II) while 1:2 electrolytes for Ni(II) complexes. Thus, these complexes may be formulated as [M(L)X2] and [Ni(L)]X2 (where M = Mn(II), Co(II) and Cu(II) and X = Cl− and NO3−).On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been assigned for Mn(II) and Co(II) complexes, square-planar for Ni(II) whereas tetragonal for Cu(II) complexes. The ligand and its complexes were also evaluated against the growth of bacteria and pathogenic fungi in vitro. 相似文献
105.
A review is presented on thiocyanate methods for the estimation of molybdenum in a wide variety of samples. They include conventional thiocyanate methods in which molybdenum forms an orange red complex with the thiocyanate ions and improved thiocyanate methods where the sensitivity is increased through the formation of ternary ion association complex. 相似文献
106.
Chandra S Gupta LK Sangeetika 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(1-3):453-460
The complexation of new mixed thia-aza-oxa macrocycle viz., 2,12-dithio-5,9,14,18-tetraoxo-7,16-dithia-1,3,4,10,11,13-hexaazacyclooctadecane containing thiosemicarba-zone unit with a series of transition metals Co(II), Ni(II) and Cu(II) has been investigated, by different spectroscopic techniques. The structural features of the ligand have been studied by EI-mass, (1)H NMR and IR spectral techniques. Elemental analyses, magnetic moment susceptibility, molar conductance, IR, electronic, and EPR spectral studies characterized the complexes. Electronic absorption and IR spectra of the complexes indicate octahedral geometry for chloro, nitrato, thiocyanato or acetato complexes. The dimeric and neutral nature of the sulphato complexes are confirmed from magnetic susceptibility and low conductance values. Electronic spectra suggests square-planar geometry for all sulphato complexes. The redox behaviour was studied by cyclic voltammetry, show metal-centered reduction processes for all complexes. The complexes of copper show both oxidation and reduction process. The redox potentials depend on the conformation of central atom in the macrocyclic complexes. Newly synthesized macrocyclic ligand and its transition metal complexes show markedly growth inhibitory activity against pathogenic bacterias and plant pathogenic fungi under study. Most of the complexes have higher activity than that of the metal free ligand. 相似文献
107.
H Morrison B Mauclair R M Deibel G Pandey W M Baird 《Photochemistry and photobiology》1985,41(3):251-257
Abstract— Urocanic acid (UA) has previously been shown to photochemically react with N, N-dimethylthymine and with phage G4 single-stranded DNA. In this study, E-[ring-2-14C]-U A and calf thymus DNA have been irradiated with UV light (Λ > 270 nm) in buffered, aqueous solutions. Rc-isolation of the DNA indicates covalent binding of UA at levels of up to 80 nmol UA/mg DNA. Binding is observed for both native and heat denatured DNA. Equilibrium dialysis studies give no evidence for complexation of UA to either form of DNA in the dark. Enzymatic cleavage of the UA bound DNA and analysis by HPLC shows peaks for l4C-labelled products with retention volumes identical to those of a marker mixture prepared by irradiating UA with [3H-methyl]thymidine. Photolysis of the DNA before irradiation with U A leads to the formation of a second product with a retention volume corresponding to that for a deoxyadenosine/UA marker. 相似文献
108.
Summary Ruthenium(III) complexes of types [Ru(L)3], [Ru(L)Cl(H2O)2], [Ru(L)Cl2]n, [Ru(L)Cl(H2O)]n(LH =Schiff bases derived from anthranilic acid and benzaldehyde, acetophenone, vanillin, cinnamaldehyde orm-hydroxyacetophenone; LH2=Schiff bases derived from anthranilic acid and salicylaldehyde oro-hydroxyacetophenone; LH=Schiff bases derived fromp-aminobenzoic acid and benzaldehyde, acetophenone, vanillin, cinnamaldehyde orm-hydroxyacetophenone; LH2=Schiff bases derived fromp-aminobenzoic acid and salicylaldehyde oro-hydroxyacetophenone) have been synthesized and characterized on the basis of elemental analyses, conductance, magnetic moment and spectral (electronic, i.r. and1H n.m.r.) data. The wavelengths of the principal electronic absorption peaks have been accounted for quantitatively in terms of crystal field theory and various parameters have been evaluated. On the basis of the electronic spectra, an octahedral geometry has been established for all these complexes except [Ru(L)Cl2]n. The complexes [Ru(L)Cl2]n are pentacoordinate and a trigonal-bipyramidal environment, D3h, is suggested for the ruthenium(III) ion. The thermal behaviour of these complexes has also been studied by t.g., d.t.g and d.s.c techniques. Heats of reaction for the decomposition steps were calculated from the d.s.c. curves. The antifungal and antiviral activities of the complexes with Schiff bases derived from anthranilic acid were also investigated. 相似文献
109.
Kinetics of the oxidation of methyl n-propyl ketone and methyl isobutyl ketone by N-bromosuccinimide (NBS) have been studied in perchloric acid media in presence of mercuric acetate. A zero order dependence to N-bromosuccinimide and a first order dependence to both ketones and hydrogen ion concentrations have been observed. Sodium perchlorate, mercuric acetate and succinimide additions have negligible effect while methanol addition has a positive effect on the reaction rate. A solvent isotope effect (k0D2O/K0H2O = 2.3-2.7 and 2.4-2.8 for MeCOn.pr and MeCoi-Bu, respectively) has been observed at 35°. Kinetic investigations have revealed that the order of reactivity is methyl n-propyl ketone > methyl isobutyl ketone. Various thermodynamic parameters have been computed and corresponding 1,2-diketones were found to be the products. A suitable mechanism in conformity with the above observations has been proposed. 相似文献
110.
Summary The products from the reaction oftrans-dioxobis(ethylenediamine)rhenium(V) halides with hydrogen halides have been investigated. Dilute (2M) and concentrated hydrochloric acid react with (ReO2en2)Cl in the cold to give ReO(OH)enCl2 and IRe(OH)2enCl2]Cl respectively, while with hot 6M HCl [ReOCl5]2– is formed. Dilute solutions of HX protonate [ReO2en2]X (X = Br and I) giving [ReO(OH)en2]X2 which are converted slowly into ReO(OH)enBr2 and [ReO(OH)en2](I3)2. Hot and concentrated solutions of HX reduce Rev in (ReO2en2 )X (X = Br and I) giving enH2(ReBr6) and ReI4en. The thermal decomposition of (ReO2en2)X (X = Cl, Br and I) has been studied by thermogravimetry and a polymeric compound, Re2O7en2, has been isolated by heating (ReO2en2)X at 200°. The compounds have been characterised by molecular conductivities, magnetic susceptibility and i.r. spectra. 相似文献