Bibliographies thématiques / N-N bonds

Littérature scientifique sur le sujet « N-N bonds »

Auteur : Grafiati
Publié le 27 février 2024

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Articles de revues sur le sujet "N-N bonds"

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Tiritiris, Ioannis, et Willi Kantlehner. « Crystal structure ofN-[3-(dimethylazaniumyl)propyl]-N′,N′,N′′,N′′-tetramethyl-N-(N,N,N′,N′-tetramethylformamidiniumyl)guanidinium dibromide hydroxide monohydrate ». Acta Crystallographica Section E Crystallographic Communications 71, no 12 (1 décembre 2015) : o1078—o1079. http://dx.doi.org/10.1107/s2056989015024305.

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The asymmetric unit of the title hydrated salt, C15H37N63+·2Br−·OH−·H2O, contains one cation, three partial-occupancy bromide ions, one hydroxide ion and one water molecule. Refinement of the site-occupancy factors of the three disordered bromide ions converges with occupancies 0.701 (2), 0.831 (2) and 0.456 (2) summing to approximately two bromide ions per formula unit. The structure was refined as a two-component inversion twin with volume fractions 0.109 (8):0.891 (8) for the two domains. The central C3N unit of the bisamidinium ion is linked to the aliphatic propyl chain by a C—N single bond. The other two bonds in this unit have double-bond character as have the four C—N bonds to the outer NMe2groups. In contrast, the three C—N bonds to the central N atom of the (dimethylazaniumyl)propyl group have single-bond character. Delocalization of the two positive charges occurs in the N/C/N and C/N/C planes, while the third positive charge is localized on the dimethylammonium group. The crystal structure is stabilized by O—H...O, N—H...Br, O—H...Br and C—H...Br hydrogen bonds, forming a three-dimensional network.
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Ovchynnikov, Vladimir. « N,N′-Dimethyl-N′′-(trichloroacetyl)phosphoramide ». Acta Crystallographica Section E Structure Reports Online 69, no 12 (9 novembre 2013) : o1759. http://dx.doi.org/10.1107/s1600536813030389.

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In the title compound, C4H9Cl3N3O2P or CCl3C(O)NHP(O)(NHCH3)2, the P atom has a strongly distorted tetrahedral geometry due to the formation of intermolecular strong hydrogen bonds involving the N atoms. In the crystal, N—H...O=P and N—H...O=C hydrogen bonds connect the molecules into a two-dimensional array parallel to (100). An intramolecular P...O contact [P...O = 2.975 (3) Å] is observed. The CCl3group is rotationally disordered, with occupancies of 0.60 (3) and 0.40 (3)
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Orea Flores, Ma Laura, Alberto Galindo Guzmán, Dino Gnecco Medina et Sylvain Bernès. « N-Benzoyl-N,N′-dicyclohexylurea ». Acta Crystallographica Section E Structure Reports Online 62, no 7 (21 juin 2006) : o2922—o2923. http://dx.doi.org/10.1107/s1600536806022173.

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Karim, Alavi, Marcus Reitti, Anna-Carin C. Carlsson, Jürgen Gräfenstein et Máté Erdélyi. « The nature of [N–Cl–N]+and [N–F–N]+halogen bonds in solution ». Chem. Sci. 5, no 8 (2014) : 3226–33. http://dx.doi.org/10.1039/c4sc01175a.

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The solution symmetry of [N–Cl–N]+and [N–F–N]+halogen bonds is discussed, in comparison to the iodine and bromine-centered bonds as well as to the corresponding three-center [N–H–N]+hydrogen bond.
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Marek, Jaromír, Zdeněk Trávníček et Šárka Čermáková. « (N,N,N′,N′′,N′′-Pentamethyldiethylenetriamine-κ3 N,N′,N′′)(trithiocyanurato-κ2 N,S)zinc(II) ». Acta Crystallographica Section E Structure Reports Online 63, no 3 (14 février 2007) : m725—m727. http://dx.doi.org/10.1107/s1600536807006484.

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The structure of the title compound, [Zn(C9H23N3)(C3HN3S3)], consists of discrete molecules connected by N—H...S hydrogen bonds into centrosymmetric dimers. The ZnII atom is pentacoordinated in a deformed trigonal–bipyramidal geometry by three N atoms of a tridentate N,N,N′,N′′,N′′-pentamethyldiethylenetriamine ligand, and one S and one N atoms of a trithiocyanurate dianion bonded as a bidentate ligand. The crystal structure is further stabilized by close contacts of the types C—H...S and C—H...N.
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Spychała, Jarosław. « Stabilization of N-, N,N-, N,N′-methylated and unsubstituted simple amidine salts by multifurcated hydrogen bonds ». Spectroscopy 20, no 4 (2006) : 169–76. http://dx.doi.org/10.1155/2006/589273.

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In the light of the usefulness of amidines in medicinal chemistry, this paper considers the effects on biological properties and chemical reactivities of organic molecules affected by intramolecular interactions. The study of chemical shifts has been an important source of information on the electronic structure of amidine salts and their ability to form non-covalent bonds with nucleic acids. The NMR and IR results demonstrate that hydrogen bonds are a force for promoting chemical reactions. The thymine O2 carbonyl oxygen in a close proximity to the amidinium cation does interact with the appropriately spaced amidinium NH donor moieties. The1H-15N 2D NMR (GHSQC and GHMBC) spectra with natural isotopic abundance of15N fully confirm the intramolecular character of the bonds. A rule able to estimate the relative strength of the new multifurcated hydrogen bonds is given. The appearance of the ΔδNHchemical shift differences near zero is due to the strong intramolecular interactions. The strength of the H-bond donation by acetamidines is reflected in the N–H dissociation/recombination process (positive charge shift has been invoked to explain other effects on benzamidines). The temperature dependence of chemical shift for the amidine NH protons in dimethyl sulfoxide solutions is herein discussed.
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Bardajee, Ghasem Rezanejad, Mitchell A. Winnik et Alan J. Lough. « 4-[N-(2-Hydroxyethyl)-N-methylamino]-N-isopropyl-1,8-naphthalimide ». Acta Crystallographica Section E Structure Reports Online 62, no 4 (31 mars 2006) : o1615—o1617. http://dx.doi.org/10.1107/s1600536806010294.

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In the title crystal structure, C18H20N2O3, molecules are linked into centrosymmetric dimers via O—H...O hydrogen bonds [H...O = 1.92 (3) Å]. These dimers are, in turn, linked by weak C—H...O hydrogen bonds [H...O = 2.42 Å], forming a two-dimensional network.
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Cai, Xiao-Qing, et Mao-Lin Hu. « N,N′,N′′-Tricyclohexylguanidinium chloride ». Acta Crystallographica Section E Structure Reports Online 62, no 4 (8 mars 2006) : o1260—o1261. http://dx.doi.org/10.1107/s1600536806007331.

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In the title crystal structure, C19H36N3 +·Cl−, the central C atom of the N,N′,N′′-tricyclohexylguanidinium ion and the chloride ion both lie on positions of site symmetry 3. Weak N—H...Cl hydrogen bonds [N...Cl = 3.539 (3) Å] link anions and cations, forming a three-dimensional network.
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Akhtar, Muhammad, Mohammed Fettouhi, Maqsood Ahmed, Islam Ullah Khan et Saeed Ahmad. « N,N,N′,N′-Tetramethylethylenediammonium tetrachloridozincate ». Acta Crystallographica Section E Structure Reports Online 69, no 12 (6 novembre 2013) : m642. http://dx.doi.org/10.1107/s1600536813029802.

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The asymmetric unit of the title compound, (C6H18N2)[ZnCl4], consists of one tetrachloridozincate anion and two half-N,N,N′N′-tetramethylethylenediammonium cations. Each of the two diammonium cations is located about an inversion center and one of them is disordered over two sets of sites in a 0.780 (17):0.220 (17) ratio. The ZnIIatom has a slightly distorted tetrahedral coordination environment. The cations and anions are connectedviaN—H...Cl hydrogen bonds into chains extending along [0-11].
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Tiritiris, Ioannis, et Willi Kantlehner. « Crystal structure ofN,N,N′,N′,N′′,N′′-hexamethylguanidinium cyanate 1.5-hydrate ». Acta Crystallographica Section E Crystallographic Communications 71, no 12 (1 décembre 2015) : o1076—o1077. http://dx.doi.org/10.1107/s2056989015024317.

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The title hydrated salt, C7H18N3+·OCN−.1.5H2O, was synthesized starting fromN,N,N′,N′,N′′,N′′-hexamethylguanidinium chloride by a twofold anion-exchange reaction. The asymmetric unit contains two cations, two cyanate anions and three water molecules. One cation shows orientational disorder and two sets of N-atom positions were found related by a 60° rotation, with an occupancy ratio of 0.852 (6):0.148 (6). The C—N bond lengths in both guanidinium ions range from 1.329 (2) to 1.358 (10) Å, indicating double-bond character, pointing towards charge delocalization within the NCN planes. Strong O—H...N hydrogen bonds between the crystal water molecules and the cyanate ions and strong O—H...O hydrogen bonds between the water molecules are present, resulting in a two-dimensional hydrogen bonded network running parallel to the (001) plane. The hexamethylguanidinium ions are packed in between the layers built up by water molecules and cyanate ions.
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Thèses sur le sujet "N-N bonds"

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Nagarajan, V. « Study of some supramolecular assemblies mediated by N-H-O, N-H-N and N-H-S hydrogen bonds ». Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2012. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2141.

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Ahern, J. M. « Radical hydroacylation of C-C and N-N double bonds in air ». Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1309819/.

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The formation of C-C and C-N bonds in modern organic synthesis is a key target for methodological advancement. Current methods of C-C and C-N bond formation often involve the use of expensive catalysts, or sub-stoichiometric reagents, which can lead to the generation of undesirable waste products. This thesis describes a novel and environmentally benign set of reaction conditions for the formation of C-C and C-N bonds by hydroacylation and this is promoted by mixing two reagents, an aldehyde and an electron-deficient double bond, under freely available atmospheric oxygen at room temperature Chapter 1 will provide an introduction to the thesis and mainly discusses methods for C-C bond formation, in particular, radical chemistry and hydroacylation. Chapter 2 describes the hydroacylation of vinyl sulfonates and vinyl sulfones (C-C double bonds) with aliphatic and aromatic aldehydes with a discussion and evidence for the mechanism of the transformation. Chapter 3 details the synthesis of precursors for intramolecular cyclisations and studies into aerobic intramolecular cyclisations. Chapter 4 describes the hydroacylation of vinyl phosphonates (C-C double bonds) and diazocarboxylates (N-N double bonds) with aliphatic and aromatic aldehydes bearing functional groups. In addition, the hydroacylation of diazocarboxylates with chiral aldehydes will be discussed. In conclusion, a new, facile and clean set of reaction conditions for the formation of C-C and C-N bonds has been developed via aerobic C-H activation of aldehydes providing access to unsymmetrical ketones.
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Brydges, Stacey McGlinchey Michael J. « The search for correlated rotation in sterically hindered, multi-n-bladed carbon(n)argon(n)(x+/-) (n = 5, 6 and 7) propellers : from models to molecules / ». *McMaster only, 2003.

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De, Villiers Deon Bernard Malan. « Die inkomstebelastinggevolge van die verkryging van 'n skuldbrief teen 'n diskonto ». Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/20429.

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Thesis (MComm)--Stellenbosch University, 2001.
ENGLISH ABSTRACT: In this study, the income tax implications of the acquisition of a debenture at a discount is investigated. The purpose of this study is determine whether the proceeds from the redemption or disposal of the above-mentioned debenture are of a revenue or capital nature. It is customary for companies to issue debentures in order to obtain long term finance. These debentures may be issued at a discount. There exists a general uncertainty in the academic literature regarding the income tax implications of the acquisition of a debenture at a discount to the face value thereof. Section 24J of the Income Tax Act includes a discount in the definition of "interest". There is no general definition of the words "interest" and "discount" in the Income Tax Act. The lack of a statutory definition of these words contributes to the uncertainty regarding the income tax treatment of the sale or redemption of a debenture. The following aspects are discussed: (a) the revenue or capital nature of the proceeds on redemption and transfer of a debenture; (b) the provisions of section 24J of the Income Tax Act; and (c) the provisions of capital gains tax. In order to determine the revenue or capital nature of the proceeds on redemption or transfer of a debenture, the following aspects are discussed: • The attributes of a debenture from an economic and legal perspective. The factors that determine the value of the discount of a debenture are considered from an economic viewpoint. • The guidelines that apply in general to determine the revenue or capital nature of accruals are considered with specific reference to the guidelines laid down by the South African courts. A distinction is drawn between the guidelines that consider the intention of the taxpayer and those guidelines that operate independently of the intention of the taxpayer. • The general guidelines are then applied to the proceeds on redemption or transfer of a debenture. The ordinary meaning of interest and the meaning of the interest in the Income Tax Act are considered. The relation between a discount and interest is examined. Case law from England, Australia and Canada are also considered. The writer comes to the conclusion that a discount that realises on redemption of a debenture is in the nature of interest. The discount is revenue derived from capital productively employed and therefore not of a capital nature. The proceeds from the transfer of a debenture is not of a capital nature if it is a gain made by an operation of business in carrying out a scheme for profit making. The writer is of the opinion that section 24J influences the application of the general principles. The writer is of the opinion that the objective test should be applied to determine the nature of the accrual amount in terms of section 24J. The accrual amount will include a proportional amount of the discount. The objective test should be applied irrespective of whether the debenture is held until redemption or transferred before redemption. The provisions of section 24J should be applied before the capital gain or capital loss is determined in terms of the Eight Schedule to the Income Tax Act. The proceeds from disposal must be reduced by any amount of the proceeds that was included in gross income or taken into account in determining the taxable income of a person. The base cost of a debenture acquired at a premium must be reduced by the amount of the premium that was allowed as a deduction in determining the taxable income of the holder of a debenture.
AFRIKAANSE OPSOMMING: In hierdie studie word die inkomstebelastinggevolge van die verkryging van 'n skuldbrief teen 'n diskonto ondersoek. Die doel van hierdie studie is am te bepaal of die opbrengs met die aflossing en verkoop van sodanige skuldbrief van 'n inkomste- of kapitale aard is. Een van die gebruiklikste metodes vir 'n maatskappy am langtermynleningsfondse te bekom, is deur die uitreiking van skuldbriewe. Skuldbriewe kan teen 'n diskonto uitgereik word. Daar bestaan "n algemene onsekerheid in die beskikbare literatuur met betrekking tot die inkomstebelastinggevolge van "n skuldbrief wat teen "n diskonto verkry is. Artikel 24J van die Inkomstebelastingwet sluit spesifiek 'n diskonto by die omskrywing van "rente" in. Die Inkomstebe/astingwet bevat egter nie 'n algemene omskrywing van die woorde "rente" en "diskonto" nie. Die gebrek aan 'n statutere omskrywing van bogenoemde woorde dra by tot die onsekerheid van die inkomstebelastinggevolge van die aflossing of verkoop van 'n skuldbrief. Die skrywer oorweeg die volgende: (a) die inkomste- of kapitale aard van die opbrengs met aflossing en verkoop van "n skuldbrief; (b) die bepalings van artikel 24J van die Inkomstebelastingwet; en (c) die bepalings van die kapitaalwinsbelasting-wetgewing. Ten einde die inkomste- of kapitale aard van die opbrengs met aflossing en verkoop van 'n skuldbrief te bepaal, word die volgende aspekte bespreek: • Die eienskappe van 'n skuldbrief vanuit "n ekonomiese- en regsoogpunt. Die faktore wat die waarde van die diskonto van "n skuldbrief be'invloed, word vanuit In ekonomiese oogpunt oorweeg. • Die riglyne wat algemeen ter sprake is by die bepaling van die inkomste- of kapitale aard van toevallings. Daar word spesifiek na die riglyne soos deur die Suid-Afrikaanse geregshowe neergele, verwys. In Onderskeid word kortliks getref tussen die riglyne wat vereis dat In belastingpligtige se doel met betrekking tot In bate vasgestel word en daardie riglyne wat onafhanklik van In belastingpligtige se doel toegepas word, • Die algemene riglyne word op die opbrengs met aflossing en verkoop van In skuldbrief toegepas. Die gewone betekenis van rente asook die betekenis van rente ingevolge die Inkomstebelastingwet word oorweeg. Die verband tussen In diskonto en rente word ondersoek. Engelse, Australiese en Kanadese regspraak word oorweeg. Die skrywer kom tot die gevolgtrekking dat In diskonto wat met die aflossing van In skuldbrief realiseer, rente van aard is. In Diskonto wat met aflossing realiseer is In bedrag voortgebring deur kapitaal produktief aan te wend en dus nie van In kapitale aard nie. In Opbrengs met die oordrag van In skuldbrief is nie van In kapitale aard nie indien dit verkry is uit die beoefening van In besigheidshandeling in die uitvoering van In skema van winsbejag. Die skrywer is van mening dat artikel 24J die toepassing van die algemene riglyne be'invloed. Die skrywer is van mening dat die objektiewe riglyn toegepas moet word am die aard van toevallingsbedrae soos ingevolge. artikel 24J bereken vas te stel. In Toevallingsbedrag sluit In proporsionele gedeelte van In diskonto in. Die objektiewe riglyn moet toegepas word ongeag of 'n skuldbrief tot op die aflosdatum gehou word of daarvoor oorgedra word. Die bepalings van artikel 24J moet toegepas word voordat die kapitaalwins of - verlies ingevolge die Agtste Bylae bereken word. Die opbrengs moet verminder word met enige bedrag wat by bruto inkomste ingesluit word of in ag geneem word by die vasstelling van belasbare inkomste. Die basiskoste van 'n skuldbrief wat teen 'n premie verkry is moet aangepas word met die bedrag van die premie wat reeds in ag geneem is am die belasbare inkomste van die houer van 'n skuldbrief te bepaal.
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Bemowski, Ross David. « Novel N-heterocyclic dicarbene ligands and molybdenum and dimolybdenum N-heterocyclic carbene complexes ». Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/1291.

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The syntheses of a new class of polycyclic TriAmino DiCarbenes (TADCs), based on 3,9-diazajulolidine, and their precursors and adducts are described. Starting with 2,6-dimethyl-nitrobenzene, 2,6-bis ((alkylamino)methyl)anilines (alkyl = isopropyl, mesityl, and tert-butyl) were synthesized in 40% yield over five steps. These triamines were then di-cyclized stepwise to diformamidinium dications or formamidinium/2-methoxyformaminals using oxonium salts and trialkyl orthoformates. A diformamidinium dication was characterized by single-crystal X-ray diffractometry. Treatment with various bases, particularly lithium hexamethyldisilylazide, led to the novel TADCs and monocarbenes, two of which were isolated and characterized by 1H and 13C NMR spectroscopies. In both cases, treatment with elemental sulfur trapped the TADCs as dithiobiurets. No TADC-transition metal complexes were successfully isolated from reactions of the diformamidinium dications or LiHMDS TADC complex with a number of transition metal complexes. With the exception of these two cases, all other TADCs were not isolated because they rapidly reacted to form dimers, trimers, and tetramers. One of these dimers was isolated and its structure determined using 1D and 2D NMR spectroscopies, along with high-resolution electrospray ionization mass spectrometry. This revealed that the TADC had dimerized to form an ene-triamine, likely via 1,3-shift of a benzylic proton. Novel N-heterocyclic Carbene (NHC) complexes of molybdenum were also synthesized and characterized. Reaction of Cp2Mo2(CO)4 (Cp = C5H5) with dimesityl-imidazol-2-ylidenes (IMes) or dimesityl-imidazolidin-2-ylidenes (SIMes) yielded the molybdoradicals CpMo(CO)2(NHC) (NHC = IMes or SIMes). The carbonyl infrared stretching frequencies and the relative metal-to-NHC π-backbonding for IMes and SIMes complexes are compared. Reaction of the less bulky dimethyl-imidazol-2-ylidene (IMe) with Cp2Mo2(CO)4 yielded the Mo-Mo triple bond complex Cp2Mo2(CO)3(IMe) by CO substitution. This is the first example of an NHC-ligated metal-metal multiply bonded complex. Single crystal X-ray diffractometry of these new organomolybdenum and organodimolybdenum complexes is discussed.
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Smith, Jennifer. « Novel iridicycles for the asymmetric reduction of C=N bonds ». Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2049619/.

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The asymmetric reduction of imino bonds is a well known and utilised method of chiral amine synthesis. Chapter 1 gives an insight into the published methods for a range of substrates via hydrogenation and transfer hydrogention systems. This thesis presents a range of novel iridicycles, all of which contain chiral oxazoline and imidazoline ligands. The synthesised complexes demonstrate a variety of electronic and steric properties. Their activities are presented in the latter chapters for the asymmetric reduction of C=N bonds. Chapter 3 demonstrates the activity of the 4,5,6-trimethoxyimidazoline iridium complex for direct asymmetric reductive amination. High activity, yielding up to quantitative product is reported, under unusually mild conditions, in both aqueous and organic solvent systems. The enantioselectivites achieved were moderate to high for the substrates screened. The use of a bulky 2,4,6-tri-iso-propyloxazoline iridium complex is reported for the asymmetric reduction of quinolines, via transfer hydrogenation conditions. The tetrahydroquinolines were produced in high yields and moderate enantioselectivities. The addition of co-solvents to the aqueous system yielded improved enantioselectivies and conversions. For the reduction of pyridinium salts a bromo-dioxole imidazoline iridium complex presented high activity. This presents unprecedentedly mild conditions via a transfer hydrogenation system, producing high yields of N-benzyl piperidines. The enantioselectivites determined were high, although some could not be measured by the available means. The 2,4,6-tri-iso-propyloxazoline iridium complex further demonstrates high activity and enantioselectivity for the asymmetric hydrogenation of acyclic imines. An NMR and mechanistic study revealed the in-situ formation of a new iridium species present only in TFE.
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Akhbar, A. R. « Hydroacylation of N=N bonds via aerobic C-H activation of aldehydes, and reactions of the products thereof ». Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1456292/.

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The development of methods to construct new chemical bonds efficiently and selectively whilst minimising energy usage and waste production is of high importance in organic chemistry. Many current methods employ inefficient, costly and often toxic multi step protocols to generate new chemical bonds. The hydroacylation reaction is one method of reducing such inefficiencies. The development of an aerobic hydroacylation protocol in the Caddick group has recently allowed the functionalisation of aldehydes with a wide array of electron deficient alkenes. This process relies on trapping an acyl radical intermediate, from the auto-oxidation of aldehydes to acids, with a suitable alkene. Since aldehyde auto-oxidation takes place readily in the presence of atmospheric oxygen, the aerobic hydroacylation reaction can be conducted in aqueous media in the absence of any additional reagents. Following on from previous work in the group, this thesis describes studies towards expanding the scope of this novel methodology in the formation of C-N bonds. It also assesses the scalability of this reaction in order to make acyl hydrazides for further chemical transformations; as such, the development of protocols for the conversion of acyl hydrazides to carboxylic acid derivatives and to ketones will also be described. Chapter 1 provides an introduction to and a general overview of current methods of hydroacylation and acid derivative syntheses. Chapter 2 describes the development of conditions for, and application of aerobic hydroacylation towards C N bond formation, and the scalability of the hydroacylation reaction. Chapter 3 will focus on solving the failures of previous attempts for the conversion of acyl hydrazides to tertiary amides. Chapter 4 will demonstrate the applicability of acyl hydrazides to the synthesis of carboxylic esters and describe some of its limitations. Finally, chapter 5 will reveal acyl hydrazides as a new class of precursors for the chemoselective synthesis of ketones.
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Williams, Glynn. « The ruthenium catalysed catalysed asymmetric transfer hygrogenation of C=N bonds ». Thesis, University of Warwick, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425545.

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Hatherley, Jessica. « On the synthesis of N-O bonds in novel heterocyclic systems ». Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/42965/.

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The origins of these investigations are in the pursuit of heterocycles containing an N-O bond. This project as a whole focusses on developing earlier chance observations made by previous members of the Knight Research Group. Chapter 2 focusses on the synthesis of isoxazoles: 5-membered aromatic rings containing a nitrogen to oxygen bond. The origin of this project was the unexpected observation of a small percentage of isoxazole products in the Group’s earlier synthesis of isoxazolines, which were thought to be the oxidation products arising from using silver nitrate as a catalyst for those cyclisations. It has now been found that by using an excess of silver nitrate, isoxazoles can be selectively formed from the same hydroxylamine precursors. Chapter 3 centres on the viability of obtaining unusual 6-endo-trig products from the iodocyclisation of unsaturated tert-butyl carbonates. This Chapter is connected to the theme of N-O chemistry, as the tert-butyl carbonate starting materials were the unexpected products of a synthesis that had been designed to form hydroxylamines. The initial discovery of these unexpected 6-endo products on iodocyclisation was expanded upon to produce a series of cyclic carbonates with a procedure optimised to maximise the yield of this desired structural isomer. Chapter 4 concentrates on building saturated N-O rings onto existing cyclic systems, including transannular cyclisations - investigating previous reports of rearrangement of N and O during cyclisation and working towards a synthesis of the core-structure of the natural product Histrionicotoxin. These schemes prove the utility of this acid-catalysed hydroamination methodology in building heterocycles and the chiral products that can be gleaned from them. For the most part, this project has been concerned with methodology - solving problems and optimising key-step procedures - which can be applied to complex target molecules.
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Lindsay, Maria. « Studies directed Towards the Iridium Catalyzed Synthesis of New Carbon-Nitrogen Bonds ». ScholarWorks@UNO, 2017. http://scholarworks.uno.edu/td/2336.

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Amines are ubiquitous in nature and serve a variety of functions in living organisms. Because of this fact amines are of great biological and pharmaceutical interest. The iridium catalyst (pentamethylcyclopentadienyl) iridium dichloride dimer ([Cp*IrCl2]2) has been used in a number of ways to synthesize new carbon-nitrogen bonds. These studies were directed toward the development of a method for the iridium catalyzed N-alkylation of alpha-amino acid esters as well as the development of a strategy for synthesis of the natural product 275A. We have optimized a method for the N-alkylation for alpha-amino acid esters. Using this method, we have N-alkylated a series of alpha-amino acid esters with a variety of alcohols. We have shown that the N-alkylation of the alpha-amino acid esters works consistently and gives the desired products in moderate to high yields. We have examined the effect of this method on the chiral center of the obtained products by analyzing their optical rotation. Evaluation of these specific rotations indicated racemization was occurring but it is believed that any loss of the chiral center is due to the reaction conditions. Amphibian alkaloids are of great interest to the pharmaceutical and academic communities due to their biological activities. Unfortunately, they are not naturally available in large quantities which makes total synthesis the most common method of generating these compounds for evaluation. One amphibian alkaloid class of interest to us are the Lehmizidines. These are bicyclic ring structures consisting of a 7-member and 5-member ring with a nitrogen bridgehead. The alkaloid, 275A, was selected as a target for a general synthetic approach. This synthetic approach required the synthesis of novel diols. The construction of these diols along with a method for the synthesis of the azepane ring is presented here.
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Livres sur le sujet "N-N bonds"

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Taillefer, Marc, et Dawei Ma, dir. Amination and Formation of sp2 C-N Bonds. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-40546-4.

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Catalyst Design for the Ionic Hydrogenation of C=N Bonds. [New York, N.Y.?] : [publisher not identified], 2015.

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Orchis, Courtesy, dir. A Bag of Bones N' Chocolate Biscuits. England : Nine Hearts Publishing, 2003.

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Mould, Chris. Dust 'n' bones : Ten terrifying classic and original ghost stories. London : Hodder Children's Books, 2006.

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Mould, Chris. Dust 'n' bones : Ten terrifying classic and original ghost stories. London : Hodder & Stoughton, 2011.

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W, Bauschlicher Charles, Taylor Peter R et United States. National Aeronautics and Space Administration., dir. The computation of C-C and N-N bond dissociation energies for singly, doubly, and triply bonded systems. [Washington, DC : National Aeronautics and Space Administration, 1989.

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W, Bauschlicher Charles, Taylor Peter R et United States. National Aeronautics and Space Administration., dir. The computation of C-C and N-N bond dissociation energies for singly, doubly, and triply bonded systems. [Washington, DC : National Aeronautics and Space Administration, 1989.

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W, Bauschlicher Charles, Taylor Peter R et United States. National Aeronautics and Space Administration., dir. The computation of C-C and N-N bond dissociation energies for singly, doubly, and triply bonded systems. [Washington, DC : National Aeronautics and Space Administration, 1989.

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Robert, Sellers, dir. The true adventures of the world's greatest stuntman : My life as Indiana Jones, James Bond, Superman and other movie heroes. London : Titan, 2011.

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Grohs, Karlheinz. Schwarz-rot-goldene Bon(n)bons : Ein Minister, der vom Baum fiel und andere Bonner Schmunzelgeschichten. Bonn : Bouvier Verlag, 1998.

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Chapitres de livres sur le sujet "N-N bonds"

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Whitfield, H. J. « Giving Heterocycles Containing B-N or N-N Bonds ». Dans Inorganic Reactions and Methods, 122. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470145210.ch85.

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Turner, Nicholas J. « Oxidation of CN Bonds ». Dans Enzyme Catalysis in Organic Synthesis, 1535–52. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2012. http://dx.doi.org/10.1002/9783527639861.ch35.

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Atwood, David A. « (IV) into N-C (Aryl) Bonds ». Dans Inorganic Reactions and Methods, 160. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470145296.ch145.

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Atwood, David A. « (V) Into B-N Triple Bonds ». Dans Inorganic Reactions and Methods, 160. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470145296.ch146.

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Jiang, Yongwen, et Dawei Ma. « Assembly of N-Containing Heterocycles via Pd- and Cu-Catalyzed C–N Bond Formation Reactions ». Dans Amination and Formation of sp2 C-N Bonds, 87–118. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/3418_2013_61.

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Correa, Arkaitz, et Carsten Bolm. « Metal-Catalyzed C(sp2)–N Bond Formation ». Dans Amination and Formation of sp2 C-N Bonds, 55–85. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/3418_2012_57.

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Monnier, Florian, et Marc Taillefer. « Copper-Catalyzed C(aryl)–N Bond Formation ». Dans Amination and Formation of sp2 C-N Bonds, 173–204. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/3418_2013_69.

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Kibayashi, C., et N. Yamazaki. « Addition to Imine Bonds ». Dans Acetals : O/N, S/S, S/N, and N/N and Higher Heteroatom Analogues, 1. Georg Thieme Verlag KG, 2007. http://dx.doi.org/10.1055/sos-sd-030-00018.

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Kibayashi, C., et N. Yamazaki. « Addition to Carbonyl Bonds ». Dans Acetals : O/N, S/S, S/N, and N/N and Higher Heteroatom Analogues, 1. Georg Thieme Verlag KG, 2007. http://dx.doi.org/10.1055/sos-sd-030-00019.

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Takeda, T., et A. Tsubouchi. « Reduction of C=C Bonds ». Dans Acetals : O/N, S/S, S/N, and N/N and Higher Heteroatom Analogues, 1. Georg Thieme Verlag KG, 2007. http://dx.doi.org/10.1055/sos-sd-030-00136.

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Actes de conférences sur le sujet "N-N bonds"

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Procyk, R., et B. Blomback. « ROLE OF DISULFIDE BONDS NEAR THE CALCIUM BINDING SITES IN FIBRINOGEN ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642939.

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Incubation of fibrinogen with 0.5 mM dithiothreitol in the presence of .20 mM calcium chloride cleaved disulfide bonds located at: the N-terminal end of the Aα-chain (either Aα28-Aα28 or Aα45-γ23), the C-terminal end of the Aα-chain (Aα442-Aα472) and the N-terminal end of the γ-chain (either of the symmetrical γ8, γ9 disulfides or the Aα45-γ23 disulfide bond). In the absence of calcium ions two additional disulfides, γ326-γ339, and one in the N-terminal end of the γ-chain were reduced.Plasmin digestion of the reduced fibrinogens in buffers containing calcium chloride produced fragments D and E, except that smaller fragments of D were generated from the fibrinogen in which the γ326-γ339 disulfide bonds were reduced and alkylated. In these samples calcium did not protect the C-terminal end of the γ-chain from extensive digestion.Addition of thrombin to partially reduced and alkylated fibrinogen prepared in the presence of calcium gave a clotting time similar to control unreduced fibrinogen. However, when the γ326-γ339 disulfide bonds and another γ-chain disulfide bond most likely in the N-terminal region were cleaved in reduced fibrinogen prepared in the absence of calcium, the thrombin clotting time was extremely prolonged. Apparently the disulfide bonded structure supported by γ326-γ339 was important both for binding of calcium and also for normal clotting.
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Saci, L., R. Mahamdi et F. Mansour. « FTIR investigations on X-N bonds of annealed PolySi/NIDOS films ». Dans 2013 8th International Conference on Electrical and Electronics Engineering (ELECO). IEEE, 2013. http://dx.doi.org/10.1109/eleco.2013.6713872.

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PRASAD, DIPAK, et NILANJAN MITRA. « EVOLUTION OF VISCOSITY UPON CROSSLINKING IN EPOXY RESIN : AN ATOMISTIC INVESTIGATION ». Dans Proceedings for the American Society for Composites-Thirty Eighth Technical Conference. Destech Publications, Inc., 2023. http://dx.doi.org/10.12783/asc38/36619.

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Adhesive materials such as epoxy resin (DGEBA/DETDA) are crucial in formation of any laminated and sandwich composites. Typically for these thermoset polymeric adhesives, crosslinking is an important step which eventually determines the thermomechanical response of the resultant composite. During this process of cross linking of epoxy resin, one observes changes in the viscosity of the resultant composite mixture of the resin and the hardener as well as change in temperature. This crosslinking of thermoset resins (DGEBA/DETDA at 2:1 ratio) is a complex chemical reaction process involving breaking of oxirane ring (C-O bond) in DGEBA, breaking of N-H bond in the amine (DETDA) and creation of N-C covalent bonds between the resin and the hardener. Apart from formation of new covalent bonds in the process, numerous non-covalent bonds such as hydrogen bonds and van der Waals interactions are also formed. This study is aimed at fundamental understanding of the correlation between viscosity changes in the composite upon crosslinking with the evolution of these non-covalent bonds. The study is primarily based upon molecular/atomistic investigations.
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Marco de Lucas, M. C., J. M. Chappé, L. Cunha, C. Moura, J. F. Pierson, L. Imhoff, V. Potin et al. « Structure and Chemical Bonds in Black Ti(C, N, O) Thin Films ». Dans XXII INTERNATIONAL CONFERENCE ON RAMAN SPECTROSCOPY. AIP, 2010. http://dx.doi.org/10.1063/1.3482693.

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Duan, Shanzhong, et Andrew Ries. « An Efficient O(N) Algorithm for Computer Simulation of Rigid Body Molecular Dynamics ». Dans ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42032.

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Molecular dynamics is effective for a nano-scale phenomenon analysis. There are two major computational costs associated with computer simulation of atomistic molecular dynamics. They are calculation of the interaction forces and formation/solution of equations of motion. In this paper, an O(N) (order N) procedure is presented for calculation of the interaction forces and formation/solution of equations of motion. For computational costs associated with potentials or interaction forces, an internal coordinate method is used. Use of the internal coordinate method makes application of multi-rigid body molecular dynamics to an atomistic molecular system become possible. The algorithm based on the method makes the calculation considerably more practical for large-scale problems encountered in molecular dynamics such as conformation dynamics of polymers. For computational costs associated with formation/solution of equations of motion, Kane method and the internal coordinate method are used for recursive formation and solution of equations of motion of an atomistic molecular system. However, in computer simulation of atomistic molecular dynamics, the inclusion of lightly excited all degrees of freedom of an atom, such as inter-atomic oscillations and rotation about double bonds with high frequencies, introduces limitations to the simulation. The high frequencies of these degrees of freedom force the use of very small integration step sizes, which severely limit the time scales for the atomic molecular simulation over long periods of time. To improve this, holonomic constraints such as strictly constant bond lengths and bond angles are introduced to freeze these high frequency degrees of freedom since they have insignificant effect on long time scale processes in conformational dynamics. In this way, the procedure developed in multibody dynamics can be utilized to achieve higher computing efficiency and an O(N) computational performance can be realized for formation/solution of equations of motion.
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Klasová, Lenka, Karel Huml, Jana Barthová, Karel Ubik, Václav Kašička, Josef Škarda, Linda Hauzerová et al. « Semisynthetic preparation of human insulin analogs containing N-methylated B24-B25 or B25-B26 peptide bonds ». Dans VIth Conference Biologically Active Peptides. Prague : Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 1999. http://dx.doi.org/10.1135/css199903085.

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Surodin, S. I., D. E. Nikolitchev, R. N. Kryukov, A. I. Belov, D. S. Korolev, A. N. Mikhaylov et D. I. Tetelbaum. « Distribution of species and Ga–N bonds in silicon co-implanted with gallium and nitrogen ions ». Dans MEDICAL PHYSICS : Fourteenth Mexican Symposium on Medical Physics. Author(s), 2016. http://dx.doi.org/10.1063/1.4954368.

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Sheng, Yu-Ting, Shih-Yuan Wang, Mofei Li, Yu-Hung Chiu, Yi-Heng Lu, Chun-Man Tu et Yi-Chu Shih. « Spatial Glass Bonds Computation and fabrication system of complex glass structure ». Dans 37 Education and Research in Computer Aided Architectural Design in Europe and XXIII Iberoamerican Society of Digital Graphics, Joint Conference (N. 1). São Paulo : Editora Blucher, 2019. http://dx.doi.org/10.5151/proceedings-ecaadesigradi2019_368.

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Hartung, Jens, Markus Heubes, Rainer Kneuer et Michaela Schwarz. « Dynamic Behaviour of Cyclic Thiohydroxamic Acid Derivatives Barrier to Rotation about N2O Bonds in 4-Substituted N-Isopropoxythiazole-2(3H)-thiones and N-Isopropoxypyridine-2(1H)-thione ». Dans The 4th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland : MDPI, 2000. http://dx.doi.org/10.3390/ecsoc-4-01931.

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Runser, Claude, Marguerite Barzoukas, Alain Fort, Mireille Blanchard-Desce et Jean-Marie Lehn. « Push-pull polyenes with enhanced quadratic nonlinear susceptibilities ». Dans The European Conference on Lasers and Electro-Optics. Washington, D.C. : Optica Publishing Group, 1994. http://dx.doi.org/10.1364/cleo_europe.1994.cwf42.

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Organic molecules have been extensively studied in view of their potential applications for second-harmonic generation and electrooptic modulation in nonlinear optics.1 Molecules bearing a donor- acceptor (or push-pull) substituted π electron system can yield significant quadratic hyperpolarizabilities β. In addition, early experimental studies on para disubstituted polyenic systems have shown superlinear dependences of β with the length of the conjugation path linking the electron-donating and electron-accepting end groups.2−4 Also semiempirical calculations conducted on two series of push-pull polyene series predicted a rapid increase in β with the number n of double bonds, the effect per unit volume saturating beyond n = 20.5 Clearly longer push-pull polyenes are relevant candidates for the design of compounds with dramatically enhanced nonlinearities.
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Rapports d'organisations sur le sujet "N-N bonds"

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I. A. Parshikov, Igor A. OXIDATION OF GERANYL-N-PHENYLCARBAMATE BY FUNGUS BEAUVERIA BASSIANA WITH AIM TO OBTANING OF NEW ANTI-CANCER DRUGS. Intellectual Archive, octobre 2020. http://dx.doi.org/10.32370/iaj.2427.

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The microbial oxidation of geranyl-N-phenylcarbamate by fungus Beauveria bassiana was investigated. Oxidation of the C3 – C4 double bond of the parent molecule leads to regioselective formation of O-3,4-epoxyheranyl-N-phenylcarbamate in 30 % yield
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Miller, B. Catalysis and co-catalysis of bond cleavages in coal and coal analogs. [N,N-Dimethylaniline]. Office of Scientific and Technical Information (OSTI), janvier 1992. http://dx.doi.org/10.2172/5603118.

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Hoover, Donald R. Deriving and Applying Improved Upper Bounds for Multivariate Normal Probability Outside of N-Cubes. Fort Belvoir, VA : Defense Technical Information Center, juillet 1988. http://dx.doi.org/10.21236/ada198193.

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Huang, S. X., J. L. Gland et D. A. Fischer. Aniline hydrogenolysis on the Pt(111) single crystal surface : Mechanisms for C-N bond activation. Office of Scientific and Technical Information (OSTI), décembre 1993. http://dx.doi.org/10.2172/10117539.

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Gland, J. L. Hydrogen induced C-C, C-N, and C-S bond activation on Pt and Ni surfaces. Office of Scientific and Technical Information (OSTI), décembre 1992. http://dx.doi.org/10.2172/10102894.

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Gland, J. L. Hydrogen induced C-C, C-N, and C-S bond activation on Pt and Ni surfaces. Office of Scientific and Technical Information (OSTI), janvier 1992. http://dx.doi.org/10.2172/6915688.

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Gland, J. L. Hydrogen Induced C-C, C-N, & ; C-S Bond Activation on Pt & ; Ni Surfaces. Office of Scientific and Technical Information (OSTI), juillet 2004. http://dx.doi.org/10.2172/830711.

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Gland, J. L. [Hydrogen induced C-C, C-N, and C-S bond activities on Pi and Ni surfaces] : Summary. Office of Scientific and Technical Information (OSTI), décembre 1994. http://dx.doi.org/10.2172/10110807.

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Zarrieß, Benjamin, et Patrick Koopmann. On the Complexity of Verifying Timed Golog Programs over Description Logic Actions (Extended Version). Technische Universität Dresden, 2018. http://dx.doi.org/10.25368/2022.241.

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Golog programs allow to model complex behaviour of agents by combining primitive actions defined in a Situation Calculus theory using imperative and non-deterministic programming language constructs. In general, verifying temporal properties of Golog programs is undecidable. One way to establish decidability is to restrict the logic used by the program to a Description Logic (DL), for which recently some complexity upper bounds for verification problem have been established. However, so far it was open whether these results are tight, and lightweight DLs such as EL have not been studied at all. Furthermore, these results only apply to a setting where actions do not consume time, and the properties to be verified only refer to the timeline in a qualitative way. In a lot of applications, this is an unrealistic assumption. In this work, we study the verification problem for timed Golog programs, in which actions can be assigned differing durations, and temporal properties are specified in a metric branching time logic. This allows to annotate temporal properties with time intervals over which they are evaluated, to specify for example that some property should hold for at least n time units, or should become specified within some specified time window. We establish tight complexity bounds of the verification problem for both expressive and lightweight DLs. Our lower bounds already apply to a very limited fragment of the verification problem, and close open complexity bounds for the non-metrical cases studied before.
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Visser, R., H. Kao, R. M. H. Dokht, A. B. Mahani et S. Venables. A comprehensive earthquake catalogue for northeastern British Columbia : the northern Montney trend from 2017 to 2020 and the Kiskatinaw Seismic Monitoring and Mitigation Area from 2019 to 2020. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/329078.

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To increase our understanding of induced seismicity, we develop and implement methods to enhance seismic monitoring capabilities in northeastern British Columbia (NE BC). We deploy two different machine learning models to identify earthquake phases using waveform data from regional seismic stations and utilize an earthquake database management system to streamline the construction and maintenance of an up-to-date earthquake catalogue. The completion of this study allows for a comprehensive catalogue in NE BC from 2014 to 2020 by building upon our previous 2014-2016 and 2017-2018 catalogues. The bounds of the area where earthquakes were located were between 55.5°N-60.0°N and 119.8°W-123.5°W. The earthquakes in the catalogue were initially detected by machine learning models, then reviewed by an analyst to confirm correct identification, and finally located using the Non-Linear Location (NonLinLoc) algorithm. Two distinct sub-areas within the bounds consider different periods to supplement what was not covered in previously published reports - the Northern Montney Trend (NMT) is covered from 2017 to 2020 while the Kiskatinaw Seismic Monitoring and Mitigation Area (KSMMA) is covered from 2019 to 2020. The two sub-areas are distinguished by the BC Oil & Gas Commission (BCOGC) due to differences in their geographic location and geology. The catalogue was produced by picking arrival phases on continuous seismic waveforms from 51 stations operated by various organizations in the region. A total of 17,908 events passed our quality control criteria and are included in the final catalogue. Comparably, the routine Canadian National Seismograph Network (CNSN) catalogue reports 207 seismic events - all events in the CNSN catalogue are present in our catalogue. Our catalogue benefits from the use of enhanced station coverage and improved methodology. The total number of events in our catalogue in 2017, 2018, 2019, and 2020 were 62, 47, 9579 and 8220, respectively. The first two years correspond to seismicity in the NMT where poor station coverage makes it difficult to detect small magnitude events. The magnitude of completeness within the KSMMA (ML = ~0.7) is significantly smaller than that obtained for the NMT (ML = ~1.4). The new catalogue is released with separate files for origins, arrivals, and magnitudes which can be joined using the unique ID assigned to each event.
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