Showing papers on "Hydrazine published in 1993"
TL;DR: In this paper, the N-N bond is cleaved by reduction in the presence of protons in tungsten complexes, in particular W(IV) and W(V) hydrazine and hydrazido complexes.
Abstract: Chemistry of tungsten complexes in which N-N bond cleavage occurs, in particular W(IV) hydrazine and W(V) hydrazido complexes. Reactions in which the N-N bond is cleaved by reduction in the presence of protons also are discussed
107 citations
TL;DR: Monitoring of hydrazine and monomethylhydrazine in air using a hand-held ion mobility spectrometer on the space shuttle Atlantis during mission STS-37 suggests that drift times are governed by ion-cluster equilibria in the drift region of the mobility spectrumeter.
Abstract: Hydrazine (HZ) and monomethylhydrazine (MMH) in air were monitored continuously using a hand-held ion mobility spectrometer equipped with membrane inlet, 63Ni ion source, acetone reagent gas, and ambient temperature drift tube. Response characteristics included detection limit, 6 ppb; linear range, 10-600 ppb; saturated response, >2 ppm; and stable response after 15-30 min. Ammonia interfered in hydrazines detection through a product ion with the same drift time as that for MMH and HZ. Acetone reagent gas was replaced with 5-nonanone to alter drift times of product ions and separate ammonia from MMH and HZ. Patterns in mobility spectra, ion identifications from mass spectra, and fragmentation cross-sections from collisional-induced dissociations suggest that drift times are governed by ion-cluster equilibria in the drift region of the mobility spectrometer. Practical aspects including calibration, stability, and reproducibility are reported from the use of a hand-held mobility spectrometer on the space shuttle Atlantis during mission STS-37.
66 citations
TL;DR: In this article, the derivatization of hydrazine with 2,3-naphthalene dicarboxaldehyde (NDA) followed by fluorescence detection is shown to be an effective method for the selective determination of extremely low concentrations of HZ in solution.
61 citations
TL;DR: The crystal structure of a potential DNA damaging and mutagenic agent, 2,4-dinitrophenylhydrazine, has been determined as mentioned in this paper, and the four nitro O atoms and the amino N atom of the hydrazine side chain are almost in the same plane as the phenyl ring.
Abstract: The crystal structure of a potential DNA damaging and mutagenic agent, 2,4-dinitrophenylhydrazine, has been determined. The four nitro O atoms and the amino N atom of the hydrazine side chain are almost in the same plane as the phenyl ring. The three-dimensional arrangement of the molecules is held together by hydrogen bonds between nitro O atoms and the imino and amino groups of the hydrazine side chain
60 citations
59 citations
TL;DR: In this article, the catalytic effect of iron wires on plasma syntheses of ammonia and hydrazine has been studied in the nitrogen-hydrogen plasma prepared using rf discharge at a pressure of 650 Pa (5 Torr).
Abstract: The catalytic effect of iron wires on plasma syntheses of ammonia and hydrazine has been studied in the nitrogen-hydrogen plasma prepared using rf discharge at a pressure of 650 Pa (5 Torr). The product was mainly ammonia including a small amount of hydrazine. When iron wires were placed in the plasma downstream of the gas flow, the yields of both products increased, about two times in ammonia and two orders of magnitude in hydrazine. The yields increased with increasing number of wires (the surface area of the catalyst). The dissociative adsorption of nitrogen molecules and/or molecular ions on the iron surface and the formation of NHx by the reaction with hydrogen in the plasma followed by the formation of NH3 or N2H4 are considered as a reaction scheme. This is supported by the identification of NH3 with XPS of the surface of iron wires.
52 citations
TL;DR: In this paper, four-σ-bond-linked bis(hydrazine) radical cations s3.+, a3, a4, a5, a6, and a8.+ showed broad visible a with λ max =512-548 nm in CH 3 CN at room temperature, attributed to Hush-type charge-transfer bands.
Abstract: Four-σ-bond-linked bis(hydrazine) radical cations s3 .+ , a3 .+ , and a8 .+ show broad visible a with λ max =512-548 nm in CH 3 CN at room temperature, attributed to Hush-type charge-transfer bands (transition energies E op =52.2-55.8 kcal/mol). The corresponding bis(hydrazyl) radical cations s2 .+ , a2 .+ , and a7 .+ show near-IR asorption with λ max =1062-1199 nm (E op =26.9-29.3 kcal/mol). The large difference in E op is caused by innersphere reorganization energy differences, which are predicted well by AM1 semiempirical molecular orbital calculations
49 citations
TL;DR: A 3-step synthesis to the title compounds has been developed which provides them differentially protected at nitrogen as discussed by the authors, and these could then be selectively deprotected using hydrazine hydrate or hydrogenolysis over Pd/C.
42 citations
Patent•
07 Jun 1993TL;DR: In this article, a refractory metal nitride is used as a barrier metal material for interconnection in a semiconductor device, and a natural oxide film on the surface of the silicon layer set in a pressure-reduced atmosphere is removed by reducing with hydrazine or a hydrine alkyl compound.
Abstract: A refractory metal nitride is deposited at a temperature of 600° C. according to a chemical vapor phase deposition method by using a source gas containing a refractory metallic element and a reduction gas containing one of an alkyl amino compound, alkyl azide compound, hydrazine and a hydrazine alkyl compound for reducing the source gas. This refractory metal nitride is used as a barrier metal material for interconnection in a semiconductor device. When forming a refractory metal nitride as a barrier metal on a silicon layer or forming a contact metal between the barrier metal and the silicon layer, a natural oxide film on the surface of the silicon layer set in a pressure-reduced atmosphere is removed by reducing with hydrazine or a hydrazine alkyl compound.
37 citations
TL;DR: In this paper, it was shown that the reaction of 1,1,1.5,5, 5,5-hexafluoropentane-2,4-dione with hydrazine (N 2 H 4 ) in boiling ethanol gives 3,5 bis(trifluoromethyl)pyrazole, but reaction with N -aryl or N -aroyl hydrazines gives the 1-aryl- or 1-ARoyl-3, 5-dihydro-5-hydroxypyrazoles
35 citations
Journal Article•
TL;DR: In this article, a trifluoromethyl substituted heterocycles have been prepared by condensation of the new beta-trifluoroacetyl-lactams 1 and -benzolactams 2 with methylhydrazine and benzamidine as bis-nucleophiles without opening of the lactam structure.
TL;DR: An increased hydrazine level was found after in vitro degradation from isoniazid in human serum, and no degradation ofhydrazine was found in spiked plasma and serum, even after storage at room temperature for one week.
TL;DR: In this paper, the electrochemical behavior of hydrazine on platinum single crystal electrodes with basal orientations has been studied in 0.5 M H 2 SO 4 by means of cyclic voltammetry.
TL;DR: In this article, high molecular weight new poly(ether imide)s were obtained in one step by reaction between dianhydrides and bis(N-amino imides)s.
Abstract: High molecular weight new poly(ether imide)s were obtained in one step by reaction between dianhydrides and bis(N-amino imide)s. All the polymers show extremely high T g 's (307-436°C) and high thermal stability (5% weight loss temperatures above 500°C under air or nitrogen). They are soluble in organic solvents such as NMP, m-cresol and o-DCB. Thermomechanical studies show that all the polymers maintain their properties up to 200-300°C
Journal Article•
TL;DR: In this paper, the reduction of salts in nuclear fuel reprocessing is discussed and it is shown that this can be accomplished using organic derivatives of hydrazine and hydroxylamine as reductants of Np(VI) and Pu(IV).
Abstract: An important issue in nuclear fuel reprocessing is the reduction of salts. It is seen that this can be accomplished utilizing organic derivatives of hydrazine and hydroxylamine as reductants of Np(VI) and Pu(IV). The chemistry of this process is described.
TL;DR: An easy, thermally initiated reaction of homoallenylazine 1 affords the new fused heterocyclic system as mentioned in this paper consisting of four five-membered rings in tenmembered carbocycle around the hydrazine moiety.
TL;DR: In this paper, N-4,4-Dimethyl-2,6-dioxocyclohexylidenemethyl (Dcm) amino acids are readily prepared and the protecting group can be removed with hydrazine at room temperature; their potential in solid phase peptide synthesis is illustrated.
Abstract: N-4,4-Dimethyl-2,6-dioxocyclohexylidenemethyl (Dcm) amino acids are readily prepared and the protecting group can be removed with hydrazine at room temperature; their potential in solid phase peptide synthesis is illustrated.
Patent•
14 Jan 1993
TL;DR: In this paper, an electrochemical measuring cell for the determination of ammonia, amines, hydrazine and hydrazines derivatives, with a measuring electrode in an electrolyte which is provided with a coating made of a transition metal oxide, is described.
Abstract: An electrochemical measuring cell for the determination of ammonia, amines, hydrazine and hydrazine derivatives, with a measuring electrode in an electrolyte which is provided with a coating made of a transition metal oxide, is to be improved in such a way that the measuring sensitivity thereof, especially under continuous load, is increased and its cross sensitivity, especially with regard to NO2 and SO2, is reduced. To this end, it is provided that the oxide components of the coating (12) are formed from a metallically conductive oxide or oxide mixture of an element or of a plurality of elements of the platinum metal group. The oxides of ruthenium and iridium have been found to be particularly expedient.
TL;DR: In this paper, a coulometric method was developed for the determination of hydrazine and monomethylhydrazine (MMH) in solution, which can readily be used in conjunction with impingers to measure the amount of hydrazine and MMH in air.
Abstract: A sensitive and simple coulometric method has been developed for the determination of hydrazine and monomethylhydrazine (MMH) in solution. This coulometric method can readily be used in conjunction with impingers to measure the amount of hydrazine and MMH in air. The method has a limit of detection of less than 25 ng of hydrazine or MMH in 40 mL of solution, which corresponds to less than 2 ppb in 10 L of air. External standards are not necessary as calibration can be performed electronically. The dynamic range of the coulometric method extends from 25 ng to greater than 2500 ng in 40 mL of solution. At the higher concentrations the relative standard deviation was about 2%. The method gave excellent agreement with the two current National Institute for Occupational Safety and Health approved methods at the higher end of this concentration range.
TL;DR: In this article, the anodic oxidation kinetics of hydrazine on glassy carbon electrodes in acetonitrile were examined by cyclic voltammetry, a rotating ringdisc electrode technique and chronoamperometry.
TL;DR: The N-isopropylated hydrazine radical cations from 7 (22/tBu,iPr) and 9 ( 22/iPr 2 ) are isolable and are the first examples of isolable HRSs which lack all Ca-H bonds being protected as bridgehead carbons in bicyclic rings.
Abstract: The N-isopropylated hydrazine radical cations from 7 (22/tBu,iPr) and 9 (22/iPr 2 ) are isolable and are the first examples of isolable hydrazine radical cations which lack all Ca-H bonds being protected as bridgehead carbons in bicyclic rings. The cyclic voltammogram of 9 shows electrochemically irrevesible oxidation and reduction waves at platinum. It is argued that this results from a gearing effect of the isopropyl groups, which causes the radical cation from neutral 9 to be generated in an unstable conformation. Kinetic and thermodynamic conformational effects which cause hydrazine cyclic voltammetry curves to be electrochemically irreversible are contrasted
TL;DR: In this article, the Titania (anatase) formed has a very high surface area of 110 m2/g and zirconium titanate showed very low dielectric loss(4 × 10−4).
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TL;DR: The extreme reactivity of hydrazine and its derivatives with oxidizers such as $HNO_3$ or $N_20_4$, leading to spontaneous ignition, has been utilized in developing self-igniting (hypergolic) propellant systems as mentioned in this paper.
TL;DR: In this paper, the ability of certain additives to influence the oxide film formation characteristics on carbon steel alloy under deoxygenated alkaline pH conditions at 473 K has been investigated.
TL;DR: The synthesis of pyrazolo[4′,3′:5,6]pyridazine ring system and some of its derivatives has been accomplished such as 4-amino-1-phenyl-5,8-dioxo-, 4-AMino-5-8-dimioxo, 1-phenylon-5.8-Dioxo), 5,8dichloro-1phenyl-, 5-ethoxy-1]-pyrido[2,3-d] pyridazines as discussed by the authors.
TL;DR: In this article, the neutrophil-catalyzed metabolism of hydrazine derivatives to carbon-centered radicals was investigated by the spin-trapping technique using α -(4-pyridyl-loxide)- N - tert -butylnitrone (POBN).
TL;DR: The locations and interactions of palladium ion in H-SAPO-5 molecular sieves with oxygen, water, benzene, ammonia, carbon dioxide, carbon monoxide, pyridine, and hydrazine have been studied by electron spin resonance (ESR) and electron spin echo modulation spectroscopies.
Abstract: The locations and interactions of palladium ion in H-SAPO-5 molecular sieves with oxygen, water, benzene, ammonia, carbon dioxide, carbon monoxide, pyridine, and hydrazine have been studied by electron spin resonance (ESR) and electron spin echo modulation spectroscopies Equilibration with benzene results in several new species due to benzene interaction with Pd(I) Adsorption of ammonia produces a complex containing two molecules of ammonia based upon resolved nitrogen superhyperfine However, no resolved superhyperfine between pyridine and Pd(I) and hydrazine and Pd(I) is seen The overall ESR spectrum of the complex between hydrazine and Pd(I) is similar to that of the ammonia-Pd(I) complex, which suggests that both nitrogens of one hydrazine molecule coordinate to Pd(I) to form a complex
TL;DR: In this paper, Di-tert1-butylfluorosilyl) hydrazine, a building block for structure-isomeric N,N- and N, N′1-Bis(silyl)-hydrazines, was used to give the stable monosilylated hydrazines 1 and the six-membered ring 2.
Abstract: (Di-tert1-butylfluorosilyl)hydrazine, a Building Block for Structure-Isomeric N,N- and N,N′1-Bis(silyl)hydrazines
Di-tert1-butyldifluorosilane reacts with monolithiated hydrazine to give the stable monosilylated hydrazine 1 and the six-membered ring 2. The bis(fluorosilyl)hydrazine 3 is formed in a condensation reaction by heating 1 at 220°C. HCl elimination between 1 and chlorosilanes leads to the N,N′1-disubstituted hydrazines 4 and 5. An N,N′1-bis(silyl)hydrazine 6 is obtained in the reaction of lithiated 1 with difluorodiisopropylsilane while an N,N1-bis(silyl)hydrazine 7 is formed with tert1-butyltrifluorosilane. Structural isomerism (8–11) is observed in reactions of lithiated 1 with [(trifluorosilyl)amino]silanes.