Potassium In Liquid Ammonia Research Articles

ChemInform Abstract: Treating the Camphors with Potassium in Liquid Ammonia Leads to a Double Horeau Duplication.

ChemInform Abstract: Treating the Camphors with Potassium in Liquid Ammonia Leads to a Double Horeau Duplication.

A S8‐Like [Sb8]8‐ Zintl Anion in the Ammoniate [K17(Sb8)2(NH2)] ×17.5NH3.

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A S8‐like [Sb8]8− Zintl Anion in the Ammoniate [K17(Sb8)2(NH2)] · 17.5NH3

AbstractThe ammoniate [K17(Sb8)2(NH2)] · 17.5NH3 was synthesized by reduction of antimony with potassium in liquid ammonia. Single crystals were isolated and characterized by low temperature X‐ray structure analysis. [K17(Sb8)2(NH2)] · 17.5NH3 crystallizes in the space group P21/c (No. 14) with a = 12.976(1) Å, b = 24.536(1) Å, c = 22.858(1) Å and β = 99.17(1)°. The ammoniate contains crown‐shaped [Sb8]8− Zintl anions which are analogous to S8 rings. The presence of amide NH2− as an additional anion is deduced from coordination observations and the close similarity of structural features to the structure of KNH2.

Reductive activation of arenes

Stable cyanomethylcyclohexadienyl anions generated in two-electron reduction of isomeric tolunitriles by potassium in liquid ammonia were detected by NMR spectroscopy. The chemical shifts in these anions were obtained from density functional (PBE/3z) quantum chemical calculations and the electron density distributions for the anions were calculated in the framework of the NBO approach at the HF/6-31+G* level of theory. The experimental and calculated δ C values are in good agreement. Changes in the δ C values on going from the starting nitriles to the corresponding anions are linearly related to the calculated π-electron densities on the pentadienyl ring carbon atoms.

Structure Analyses of Dodecylated Single-Walled Carbon Nanotubes

Alkylation of nanotube salts prepared using either lithium, sodium, or potassium in liquid ammonia yields sidewall-functionalized nanotubes that are soluble in organic solvents. Atomic force microscopy and transmission electron microscopy studies of dodecylated SWNTs prepared from HiPco nanotubes and 1-iodododecane show that extensive debundling results from intercalation of the alkali metal into the SWNT ropes. TGA-FTIR analyses of samples prepared from the different metals revealed radically different thermal behavior during detachment of the dodecyl groups. The SWNTs prepared using lithium can be converted into the pristine SWNTs at 180-330 degrees C, whereas the dodecylated SWNTs prepared using sodium require a much higher temperature (380-530 degrees C) for dealkylation. SWNTs prepared using potassium behave differently, leading to detachment of the alkyl groups over the temperature range 180-500 degrees C. These differences can be observed by analysis of the solid-state 13C NMR spectra of the dodecylated SWNTs that have been prepared using the different alkali metals and may indicate differences in the relative amounts of 1,2- and 1,4-addition of the alkyl groups.

The influence of reduction and reductive alkylation on thermal properties of coals

Two samples of Polish different rank coals have been subjected to reduction and reductive alkylation in the potassium/liquid ammonia system. The samples have been studied by dilatometric (the Audibert–Arnu method), plastometric (the Giseler–Hoehne method) and thermogravimetric methods. The low-molecular-weight substances generated in the coal under the effect of potassium in liquid ammonia were found responsible for a great increase of dilatation and a shift of the softening temperature and the temperature of the maximum contraction towards lower temperatures. It was also shown that fragmentation of the coal structure led to a decrease of the temperature of the beginning of plasticity, the temperature of the maximum plasticity and to an increase of the index of maximum plasticity. The influence of C- and O-alkylation on the results of the thermal analysis was also discussed.

ChemInform Abstract: Reductive Activation of Arenes. Part 13. Reaction of Butyl Bromide with Anionic Products Formed by Reduction of 9,10‐Dicyanoanthracene with Potassium in Liquid Ammonia.

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Reductive Activation of Arenes: XIII. Reaction with Butyl Bromide of Anionic Products Formed by Reduction of 9,10-Dicyanoanthracene with Potassium in Liquid Ammonia

Reduction of 9,10-dicyanoanthracene with one equivalent of metallic potassium in liquid ammonia at -33°C gives a product which almost does not react with butyl bromide. By contrast, the two-electron reduction product reacts with butyl bromide to form, depending on the reaction conditions and procedure for treatment of the reaction mixture, one of the three compounds: 10-butyl-9-cyanoanthracene, 10-butyl-10-cyano-9,10-dihydroanthracen-9-one, or 9,10-dibutyl-9,10-dicyano-9,10-dihydroanthracene. Relatively stable 10-butyl-9,10-dicyano-9,10-dihydro-9-anthryl anion was presumed to be a common precursor of these products.

Optically active asymmetric di(tertiary phosphines). Crystal and molecular structure of [SP-4-3-(SP,S )]-{1-[(2-chlorophenyl)methylphosphino]-2-(dimethylphosphino)benzene-P,P ′ }{1-[1-(dimethylamino)ethyl]naphthyl-C 2,N }palladium(II) hexafluorophosphate

Mono-deprotonation of the bis(secondary phosphine) (RP*,RP*)- and (RP*,SP*)-1,2-phenylenebis(methylphosphine) has been achieved using potassium in liquid ammonia to give a ca. 4 ∶ 1 mixture of (±)-1-(dimethylphosphino)-2-(methylphosphino)benzene and 1,2-phenylenebis(dimethylphosphine) upon addition of a solution of methyl iodide in the same solvent. This mixture has been further treated with sodium in THF followed by the addition of 1,2-dichlorobenzene to give (±)-(2-chlorophenyl)(2-dimethylphosphinophenyl)methylphosphine and unchanged 1,2-phenylenebis(dimethylphosphine). The two di(tertiary phosphines) are readily separated by fractional distillation. Asymmetric di(tertiary phosphine) (±)-(2-chlorophenyl)(2-dimethylphosphinophenyl)methylphosphine has been resolved by separation via fractional crystallisation of internally diastereomeric palladium(II) complexes containing the racemic ligand and orthometallated (S)-dimethyl[1-(1-naphthyl)ethyl]amine. The absolute configuration of the R enantiomer of the ligand has been assigned by a crystal structure determination of the least soluble diastereomeric palladium(II) complex [SP-4-3-(SP,S)]{1-[(2-chlorophenyl)methylphosphino]-2-(dimethylphosphino)benzene-P,P′}{1-[1-(dimethylamino)ethyl]naphthyl-C2,N}palladium(II) hexafluorophosphate.

Synthesis of the First Compound with a Rhombohedral Ti6(μ3-NH)6(μ3-N)2 Core Structure by Ammonolysis of a Titanium Chelate in a Two-Phase System

Reaction of [{p-MeC6H4C(NSiMe3)2}2TiCl2] (1) with NaNH2 gave the novel titanium aggregate [{p-MeC6H4C(NSiMe3)2Ti}6(μ3-NH)6(μ3-N)2·6C7H8] (2). Treatment of 1 with potassium in liquid ammonia and toluene produced the titanium(III) complex [{p-MeC6H4C(NSiMe3)2}3Ti] (3). Compound 2 contains the largest Ti−N core so far reported.

IR and NMR characterisation of extraction products of reductively deuteromethylated coals

Products of reductive methylation and deuteromethylation of two Polish coals of different rank performed in the potassium/liquid ammonia system were subjected to extraction by dichloromethane. Spectral analysis of the extracts was made. A comparison of 1H and 2H NMR spectra indicated that the cleavage of C–C bonds in methylene bridges is of substantial importance for the fragmentation of the coal structure taking place under the effect of potassium in liquid ammonia. This finding was confirmed by results of IR analysis.

The influence of extraction with organic solvents on coking properties of raw and reduced coals

The dilatometric properties and Roga index of two orthocoking coals, subject to extraction with n-pentane, methylene chloride and chloroform, were determined in order to investigate the influence of low-molecular weight substances on coking properties of the coals. With increasing extraction yield, their dilatation and agglomerating capacity were observed to decrease, whereas their softening point was shifted towards higher temperatures. The effect of reduction by potassium in liquid ammonia on dilatometric properties of coals, as well as on their agglomerating capacity, was also studied. This reduction was found to cause a significant increase in coal dilatation, a decrease in softening temperature of the coals, and an insignificant increase in their agglomeration capacity. The extracts obtained from raw and reduced coals are characterized and their role as well as the role of the reduction process in the phenomenon of coal plasticity is discussed.

ChemInform Abstract: Reductive Activation of Arenes. Part 8. Reaction of the Product of the One‐Electron Reduction of Terephthalodinitrile with Potassium in Liquid Ammonia with Primary Alkyl Bromides.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The synthesis of tellurometalates by the reduction of binary telluride melts with potassium in liquid ammonia

The reduction of binary telluride melts with potassium in liquid ammonia in the presence of 18-Crown-6 or 2,2,2-Crypt has been employed to synthesize and precipitate tellurometalates. The method is more rapid than conventional extraction techniques and, since lower temperatures are involved, potentially unstable fragments are conserved. A melt of nominal composition CdTe3 dissolved with K and 18-Crown-6 in liquid NH3 affords [K(18-Crown-6)]4[Cd4Te12] (1) after recrystallization from CH3CN–Et2O. Compound 1 crystallizes in the triclinic space group [Formula: see text] with one formula unit in a cell of dimensions a = 12.673(1) Å, b = 13.694(3) Å, c = 14.483(3) Å, α = 117.54(2)°, β = 96.43(1)°, and γ = 100.00(1)° at 113 K. Full anisotropic refinement of the structure on Fo2 led to a value of R1 = 0.026 for those 6654 reflections having Fo2 > 2σ(Fo2). The [Cd4Te12]4− anion of 1, which may be formulated as [Cd4(Te)2(Te2)2(Te3)2]4−, consists of a rectangular array of four Cd2+ centers linked by Te2−, Te2−, and Te32− ligands. As expected from the solid-state structure, the 125Te NMR spectrum of 1 in CD3CN shows four resonances at −11, −259, −548, and −1682 ppm. A melt of nominal composition PbTe2 was dissolved with K and 2,2,2-Crypt in liquid NH3 to afford [K(2,2,2-Crypt)]2[Pb2Te3]•CH3CN (2) after recrystallization from CH3CN. Compound 2 crystallizes in the triclinic space group CI1−P1 with one formula unit in a cell of dimensions a = 11.105(3) Å, b = 11.748(4) Å, c = 11.922(3) Å, α = 118.78(2)°, β = 96.52(2)°, and γ = 91.03(3)° at 113 K. Full anisotropic refinement of the structure on Fo2 led to a value of R1 of 0.074 for those 11 135 reflections having Fo2 > 2σ(Fo2). The anion of 2 consists of a triangle of Te2− ligands capped above and below the plane by two Pb2+ centers to define a trigonal bipyramid. The 125Te NMR spectrum of 2 in CD3CN shows one resonance at −928 ppm (JPb–Te: 1090 Hz). Keywords: tellurometalates, liquid ammonia, synthesis, crystal structure.

Preparation and chemical reduction of Pt(IV) chloride-GICS: Supported Pt vs Pt inclusion graphite compounds

Different preparation methods of Pt(IV) chloride-graphite intercalation compounds from micrometer sized graphite powder and their subsequent chemical reduction are described. The reaction products were investigated by XRD, SEM, EDX and neutron activation analysis. Pt(IV) chloride-GIC was obtained by the isothermal vapour transport method of PtCl 4 between 350 and 500 °C under a pressure of chlorine gas. Reduction of Pt(IV) chloride-GIC in a tetrahydrofuran(THF)-naphthalene-K solution led to a compound containing both included potassium and potassium chloride particles and a large proportion of well distributed platinum clusters supported on the graphite flakes. The latter originate from the unremovable excess of platinum chloride systematically observed in all samples prepared by this method. The reaction of H 2PtCl 6 with graphite in SOCl 2 under an inert atmosphere also yields a Pt(IV) chloride-GIC of formula C 74PtCl 3.84. The hexachloroplatinic acid lost two HCl molecules during the intercalation process in thionyl chloride. This Pt(IV) chloride-GIC prepared in SOCl 2 was reduced either by potassium in a naphthalene-THF solution, by potassium in liquid ammonia, or by NaBHEt 3 in toluene. Irrespective of the reduction method, only Pt and KCl included in the graphite matrix were detected. The average diameter of the platinum particles was evaluated from the X-ray diffraction patterns and ranged from 27 to 38Å. When heated at 400 °C for 1 hour under a flow of argon, cubic KCl crystals and minute platinum particles emerged on the edges of the graphite flakes. It is concluded that the reduction occurs in the graphite galleries, and the reaction mechanism is discussed for each method.

Anionic products of the two‐electron reduction of aromatic nitriles in liquid ammonia

AbstractThe reduction of 9‐cyanoanthracene by two equivalents of potassium in liquid ammonia was shown to yield the 9‐cyanoanthracene dianion, whereas 1‐naptho‐ and benzonitrile gave the cyanodihydroaryl anions corresponding to the protonation of nitrile dianions at a position para to the cyano group. The 9‐cyanoanthracene dianion underwent the same transformation in the presence of a stronger protonating agent, methanol. According to 13C NMR spectral data of the generated species, the cyano group extracts the negative charge from the π‐electronic system: ca 0·20:0·25 e in the case of the 9‐cyanoanthracene dianion and ca 0·14:0·17 e in the case of cyanodihydroaryl anions. These estimations and the general NMR pattern of π‐charge distribution in all the anionic species under investigation are in accordance with data from quantum molecular orbital calculations at the PM3 and INDO levels, being reflected by the fairly good linear relationships between the changes of ring carbon chemical shifts on going to the anionic species from the respective neutral precursors on the one hand and the calculated π‐charges on the other. The para‐orienting effect of the cyano group in the protonation of nitrile dianions is discussed in terms of the π‐charge distribution in the starting dianion and the tendency to form a most stable cyanodihydroaryl anion isomer.

Reductive activation of arenes. VII. Alkylation of 9-cyanoanthracene two-electron reduction products in liquid ammonia.

The reactions of the 9-cyanoanthracene dianion generated by the action of two equivalents of potassium in liquid ammonia with primary alkyl iodides and bromides gave 9-cyano-9,10-dialkyl-9,10-dihydroanthracenes. The alkylation of the 9-cyano-9,10-dihydro-9-anthryl anion generated by the two-electron reduction of 9-cyanoanthracene in liquid ammonia in the presence of ammonium chloride gave 9-cyano-9-alkyl-9,10-dihydroanthracene. The results obtained by using cyclopropylmethyl bromide as model reagent suggest these reactions to proceed through S N mechanism. The spatial structure of 9,10-dihydroanthracene derivatives obtained is discussed.

Treating camphors with potassium in liquid ammonia leads to a double-Horeau duplication

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTreating camphors with potassium in liquid ammonia leads to a double-Horeau duplicationValentin Rautenstrauch, Patrick Megard, Bernadette Bourdin, and Anton FurrerCite this: J. Am. Chem. Soc. 1992, 114, 4, 1418–1428Publication Date (Print):February 1, 1992Publication History Published online1 May 2002Published inissue 1 February 1992https://doi.org/10.1021/ja00030a044RIGHTS & PERMISSIONSArticle Views205Altmetric-Citations22LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts

An Approach to the Total Synthesis of Diterpenoid Plant Growth Substances Isolated From Gametophytes of the Fern Genus Anemia

Reduction of the oxoindan acid (9) by potassium in liquid ammonia followed by in situ alkylation with 3-methylbut-2-enyl bromide furnished enol ether (14) which was transformed into the acetal (17) and thence aldehydes (18; R = COCH3 and COCHCl2). Acid- catalysed aldol reactions then afforded the ethanoindene derivatives (19; R=COCH3 and COCHCl2). Further elaboration gave carbinol (28) which is envisaged as an intermediate for the total synthesis of the diterpenoid antheridiogens obtained from gametophytes of the fern genus Anemia, including acid (2). The relative stereochemistry of acetal (17) was established by X-ray crystallographic analysis.

Studies of the effects of O-alkylation on the extractability of demineralized and reduced Polish coals

Two coals of different rank were modified by selective O-alkylation. The coals, which were demineralized and reduced by potassium in liquid ammonia, were then exhaustively alkylated with alkyl iodide in the presence of either tetrabutylammonium hydroxide or sodium hydroxide. Fourier transform infrared spectra of O-alkylated coals proved that the reaction occurring on oxygen atoms had not been completed though the formation of alkyl ether/esters was confirmed by NMR spectroscopy. Thus, the above alkylation methods appeared ineffective in removing the hydrogen bond network in the high volatile bituminous coal K-I (77.0% C, d.a.f.) and medium volatile bituminous coal K-II (85,7% C, d.a.f.). Instead, alkylation with dimethyl sulfate seems more efficient in destroying the hydrogen bonds and in producing extractable materials from coals.