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Literatura académica sobre el tema "Carbeni"

Autor: Grafiati

Publicado: 10 de marzo de 2023

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Artículos de revistas sobre el tema "Carbeni"

Poirel, Laurent, Michele Guibert, Samuel Bellais, Thierry Naas y Patrice Nordmann. "Integron- and Carbenicillinase-Mediated Reduced Susceptibility to Amoxicillin-Clavulanic Acid in Isolates of Multidrug-ResistantSalmonella enterica Serotype Typhimurium DT104 from French Patients". Antimicrobial Agents and Chemotherapy 43, n.º 5 (1 de mayo de 1999): 1098–104. http://dx.doi.org/10.1128/aac.43.5.1098.

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ABSTRACT Fifty-seven Salmonella enterica serotype Typhimurium (S. typhimurium) isolates were collected from human patients in two French hospitals, Hôpital Antoine Béclère (Clamart, France) and Hôpital Bicêtre (Le Kremlin-Bicêtre, France), between 1996 and 1997. Thirty of them (52 percent) were resistant to amino-, carbeni-, and ureidopenicillins, had reduced susceptibility to amoxicillin-clavulanic acid, were susceptible to cephalothin, and were resistant to sulfonamides, streptomycin, chloramphenicol, and tetracyclines. All these strains possessed a bla PSE-1-like gene and were of phage type DT104. Ten of them were studied in more detail, which revealed that bla PSE-1 is located on the variable region of a class 1 integron. This integron was found to be chromosomally located, as was another class 1 integron containingaadA2, a streptomycin-spectinomycin resistance gene. The reduced susceptibility to amoxicillin-clavulanic acid (and to ticarcillin-clavulanic acid) may result from the high level of hydrolysis of the β-lactam rather than to the clavulanic acid resistance properties of PSE-1 in these clonally related S. typhimurium isolates.

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KOROTKIKH, Nikolai, Gennady RAYENKO, Vagiz SABEROV, Vasyl YENYA, Nataliya GLINYANAYA, Alexandr AVKSENTIEV y Oles SHVAIKA. "PHILICITY OF CARBENES. A NEW VIEW". Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences 2020, n.º 60 (25 de febrero de 2020): 85–106. http://dx.doi.org/10.37827/ntsh.chem.2020.60.085.

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The electronic properties of carbenes including thermodynamic parameters such as new electronic philicity indices Ie, Ph, and for comparizon chemical hardnesses η, proton affinities (РA) calculated by DFT method (B3LYP5/6-31G*/RHF for definition of electronic indices and B3LYP5/3-21G/RHF, B3LYP5/3-21G/UHF for definition of chemical hard¬nesses) have been discussed in the paper. With their help, the estimation of philicities, electron-donating and electron-withdrawing abilities of a wide range of carbenes of both nucleophilic and electrophilic type was carried out. It was established that the philicities of carbenes according to electronic indices Іе, Ph depend on the carbenic structure (the backbone of the molecule and steric effects of substituents) and also on the reagent structure, particularly its steric effect. For typical nucleophilic carbenes, the Ph is in the range of 1–3,0, for neutral carbenes 1–1,5, IeH 8,5–22,2 eV, for neutral carbenes IeH 8,5–10,5, for typical electrophilic – in the intervals of PhH –0,3–0,5, IeH –3,4–3,4 eV. The intermediate values (Ph 0,5–1,0, IeH 3,4–8,5 eV) are characteristic for typical ambiphilic carbenes. In the evaluation of electron-donating and electron-withdrawing properties, the values of ED and EA should be taken into account (maximal EDH values were found for neutral carbene 20 (13,8 eV) and for superbasic anionic carbenes (for 22 18,4 eV)). The highest electron acceptability EAH was found for cationic carbene 29 (11,8 eV). In the reactions with carbon ions, the values of the IeH, PhH indices decrease significantly, and the electron acceptability increases. Increasing the steric effects leads to «inversion» of philicities for nucleophilic carbenes (Ph up to 0,1), and the properties of electrophilic carbenes become even more pronounced (Ph up to –2,7). The found dependences of the electronic properties of carbenes allow regulating the structure of carbenes to achieve certain characteristics, which together with stability factors can be used in the design of structures for synthesis and practical application.

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Frański, Rafał, Błażej Gierczyk, Grzegorz Schroeder, Stefan Pieper, Andreas Springer y Michael Linscheid. "Electrospray ionization mass spectrometric study of mercury complexes of N-heterocyclic carbenes derived from 1,2,4-triazolium salt precursors". Open Chemistry 5, n.º 1 (1 de marzo de 2007): 316–29. http://dx.doi.org/10.2478/s11532-006-0050-0.

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AbstractBy mixing 1,2,4-triazolium salts (precursors of N-heterocyclic carbenes 1–6) with mercury acetate, a number of complexes have been obtained under electrospray ionization condition. Carbenes 1 and 2 contain one carbene center; therefore, they are able to bond only one mercury cation. Carbenes 3–5 contain two carbene centers; therefore, they can bond two mercury cations. Mercury complexes of 1–5 always contain an acetate anion attached to a mercury cation. Carbene 6 also contains two carbene centers; however, its structure allows formation of a complex containing mercury bonded simultaneously to both centers, therefore, the complex that does not contain an acetate anion. The MS/MS spectra taken for complexes of carbenes 1–5 have shown formation of a cation corresponding to N1 substituent (adamantyl or benzyl), and those of complexes of carbenes 3–5 (doubly charged ions) have also shown the respective complementary partner ions. Mercury complex of 2 has yielded some other interesting fragmentation pathways, e.g. a loss of the HHgOOCCH3 molecule. The fragmentation pathway of the mercury complexes of 6 was found to be complicated.

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Andrada, Diego M., Nicole Holzmann, Thomas Hamadi y Gernot Frenking. "Direct estimate of the internal π-donation to the carbene centre within N-heterocyclic carbenes and related molecules". Beilstein Journal of Organic Chemistry 11 (24 de diciembre de 2015): 2727–36. http://dx.doi.org/10.3762/bjoc.11.294.

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Fifteen cyclic and acylic carbenes have been calculated with density functional theory at the BP86/def2-TZVPP level. The strength of the internal X→p(π) π-donation of heteroatoms and carbon which are bonded to the C(II) atom is estimated with the help of NBO calculations and with an energy decomposition analysis. The investigated molecules include N-heterocyclic carbenes (NHCs), the cyclic alkyl(amino)carbene (cAAC), mesoionic carbenes and ylide-stabilized carbenes. The bonding analysis suggests that the carbene centre in cAAC and in diamidocarbene have the weakest X→p(π) π-donation while mesoionic carbenes possess the strongest π-donation.

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Cui, Peng, Melissa R. Hoffbauer, Mariya Vyushkova y Vlad M. Iluc. "Heterobimetallic Pd–K carbene complexes via one-electron reductions of palladium radical carbenes". Chemical Science 7, n.º 7 (2016): 4444–52. http://dx.doi.org/10.1039/c6sc00948d.

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Unprecedented sequential substitution/reduction synthetic strategy on the Pd radical carbenes afforded heterobimetallic Pd–K carbene complexes, which features novel Pd–C_carbene–K structural moieties.

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Chen, Kai, Xiongyi Huang, Shuo-Qing Zhang, Andrew Zhou, S. B. Jennifer Kan, Xin Hong y Frances Arnold. "Engineered Cytochrome c-Catalyzed Lactone-Carbene B–H Insertion". Synlett 30, n.º 04 (14 de enero de 2019): 378–82. http://dx.doi.org/10.1055/s-0037-1611662.

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Previous work has demonstrated that variants of a heme protein, Rhodothermus marinus cytochrome c (Rma cyt c), catalyze abiological carbene boron–hydrogen (B–H) bond insertion with high efficiency and selectivity. Here we investigated this carbon–boron bond-forming chemistry with cyclic, lactone-based carbenes. Using directed evolution, we obtained a Rma cyt c variant BORLAC that shows high selectivity and efficiency for B–H insertion of 5- and 6-membered lactone carbenes (up to 24,500 total turnovers and 97.1:2.9 enantiomeric ratio). The enzyme shows low activity with a 7-membered lactone carbene. Computational studies revealed a highly twisted geometry of the 7-membered lactone carbene intermediate relative to 5- and 6-membered ones. Directed evolution of cytochrome c together with computational characterization of key iron-carbene intermediates has allowed us to expand the scope of enzymatic carbene B–H insertion to produce new lactone-based organoborons.

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García, Lucía, Khalidah H. M. Al Furaiji, David J. D. Wilson, Jason L. Dutton, Michael S. Hill y Mary F. Mahon. "Ring expansion of a ring expanded carbene". Dalton Transactions 46, n.º 36 (2017): 12015–18. http://dx.doi.org/10.1039/c7dt03046k.

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Hollóczki, Oldamur. "Unveiling the peculiar hydrogen bonding behavior of solvated N-heterocyclic carbenes". Physical Chemistry Chemical Physics 18, n.º 1 (2016): 126–40. http://dx.doi.org/10.1039/c5cp05369b.

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After fitting a molecular mechanical force field for imidazol-2-ylidenes, MD simulations revealed carbene–carbene and three-center hydrogen bonds of carbenes. The practical importance of these structures is also highlighted.

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Dong, Zhaowen, Cristian Pezzato, Andrzej Sienkiewicz, Rosario Scopelliti, Farzaneh Fadaei-Tirani y Kay Severin. "SET processes in Lewis acid–base reactions: the tritylation of N-heterocyclic carbenes". Chemical Science 11, n.º 29 (2020): 7615–18. http://dx.doi.org/10.1039/d0sc01278e.

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Pezacki, John Paul. "Normal acid/base behaviour in proton transfer reactions to alkoxy substituted carbenes: estimates for intrinsic barriers to reaction and pKa values". Canadian Journal of Chemistry 77, n.º 7 (1 de julio de 1999): 1230–40. http://dx.doi.org/10.1139/v99-087.

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Theoretical Eigen curves can be drawn through Brønsted data for dimethoxycarbene (1), phenyltrimethyl-siloxycarbene (3a), 4-methylphenyl(trimethylsiloxy)carbene (3b), 4-methoxyphenyl(trimethylsiloxy)carbene (3c), and β-naphthyl(trimethylsiloxy)carbene (3d). The Brønsted plots for these data are clearly curved with α values near 1 when proton transfer is thermodynamically unfavourable and α values near 0 when proton transfer is thermodynamically favourable, suggesting that these carbenes behave as "normal" Brønsted bases. Estimates of the intrinsic barriers (ΔG0‡) for proton transfer reactions and of the pKa values for the conjugate acids of the carbenes, extracted from these theoretical curves, have been made. The magnitudes of the intrinsic barriers (ΔG0‡) for these proton transfer reactions determined by Eigen and Marcus theories are all 1-5 kcal mol-1, suggesting that these reactions are intrinsically fast. Small intrinsic barriers also imply "normal" acid/base behaviour. Extrapolated pKa values are also the first estimates for the pKa values of the conjugate acids of carbenes 1 and 3a-3d. Key words: carbenes, proton transfer reactions, carbocations, Marcus theory, Brønsted plots.

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Tesis sobre el tema "Carbeni"

Rocchi, Federico. "Triazolilideni funzionalizzati come versatili carbeni mesoionici in complessi luminescenti". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14438/.

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1,2,3-Triazolylidenes belong to the class of abnormal N-heterocyclic carbenes, which are singlet carbenes with the carbonic center directly bound to at least one nitrogen atom of the heterocycle, and no uncharged resonance structure can be drawn. Since their precursors synthesis is quite simple and it allows the variation of the substituents on the triazolic ring, the use of 1,2,3-triazolylidenes as bidentate ligands for appropriate metallic complexes is very interesting. In the present work I report the synthesis of 1,2,3-triazolium salts 1-benzyl-3-methyl-4-(pyridin-2-yl)-1H-1,2,3-triazol-3-ium (L1-X), 3-methyl-1-phenyl-4-(pyridin-2-yl)-1H-1,2,3-triazol-3-ium (L2-X) (X=OTf, I) and 1,1'-dibenzyl-3-methyl-1H,1'H-[4,4'-bi(1,2,3-triazol)]-3-ium iodide (L3-I), that after the formation of the corresponding triazolylidenes have been employed as bidentate ancillary ligands for the synthesis of three cationic Ir(III) complexes (A-BF4, B-BF4 e C-BF4) and a neutral one (D). The synthetized complexes were characterized with NMR spectroscopy, and DFT computational calculations have been performed to compare, once photophysical characterization has been made, the obtained results with experimental measures.

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Trevisan, Mauro <1989&gt. "Preparazione e reattività di "half-sandwich" carbeni complessi stabilizzati da leganti bipiridilici". Master's Degree Thesis, Università Ca' Foscari Venezia, 2016. http://hdl.handle.net/10579/9260.

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Carbeni complessi di rutenio del tipo [Ru(η5-C5Me5)(=CAr1Ar2)bpy]BPh4 1 (Ar1= Ar2= Ph a; Ar1= Ph, Ar2= p-tolyl, b; bpy= 2,2’-bipiridile) sono stati preparati trattando il cloro complesso [RuCl(μ-Cl)( η5-C5Me5)]2 prima con una quantità stechiometrica di dipiridile in presenza di zinco metallico in THF e successivamente con un eccesso dell’appropriato diazoalcano Ar1Ar2CN2usando come solvente una miscela di etanolo e diclorometano (1:1). Lo studio della reattività dei complessi 1 ha dimostrato che questi reagiscono con fosfiti per dare i prodotti di sostituzione [Ru(η5-C5Me5)(P(OEt)3)bpy]BPh4 10. Carbeni complessi di rutenio del tipo [Ru(η5-C5Me5)(=CAr1Ar2)4,4’(CH3)2bpy]BPh4 2 (, Ar1= Ar2= Ph a; Ar1= Ph, Ar2= p-tolyl, b; byp= 4,4’-dimetilbipiridile) sono stati preparati trattando il cloro complesso [RuCl(μ-Cl)( η5-C5Me5)]2 prima con una quantità stechiometrica di 4,4’-dimetilbipiridile in presenza di zinco metallico in THF e successivamente con un eccesso dell’appropriato diazoalcano Ar1Ar2CN2usando come solvente una miscela di etanolo e diclorometano (1:1). Tutti i complessi sono stati caratterizzati spettroscopicamente attraverso l’utilizzo di IR e NMR. Il carbene complesso [Ru(η5-C5Me5)(=C(Ph)p-tolyl)bpy]BPh4 1b è stato analizzato anche mediante diffrazione dei raggi X, determinando così la struttura cristallina.

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Bortolamiol, Enrica <1992&gt. "Sintesi, caratterizzazione e attività antiproliferativa di complessi allilici di Pd (II) con leganti carbeni N-eterociclici". Master's Degree Thesis, Università Ca' Foscari Venezia, 2019. http://hdl.handle.net/10579/14269.

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L’elaborato di tesi descrive lo studio di nuovi composti allilici di Pd(II) da impiegarsi come potenziali chemioterapici. Nello specifico sono stati sintetizzati complessi contenenti come leganti di supporto diversi carbeni N-eterociclici monodentati o chelanti. La loro attività antitumorale in vitro su sei diverse linee cellulari tumorali è stata testata unitamente a quella di altri complessi allilici precedentemente sintetizzati, allo scopo di individuare i composti con la miglior citotossicità verso le cellule tumorali. Nello specifico sono stati trattati carcinoma ovarico, tumore al colon, al polmone e melanoma , valutando infine anche l’effetto dei composti su cellule normali.

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Di, Girolamo Alessandro. "4-Fenil-1,2,3-triazoli come versatili leganti ciclometallanti in complessi luminescenti di Ir(III)". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

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I complessi luminescenti di metalli di transizione costituiscono una classe di materiali che ha suscitato un notevole interesse soprattutto per le loro proprietà elettrochimiche e fotofisiche. Tra i vari complessi di metalli di transizione, i complessi di Ir(III) giocano un ruolo fondamentale in differenti applicazioni grazie alla loro versatilità sintetica, stabilità chimica e termica, elevata efficienza di emissione e modulabilità del colore emesso. Lo scopo del lavoro di Tesi è stato quello di sintetizzare complessi eterolettici luminescenti di Ir(III), basati su derivati 1,2,3-triazolilidenici e/o 1,2,3-triazolici come leganti ciclometallanti, per poi studiarne le proprietà fotofisiche ed elettrochimiche. E’ stata messa a punto una metodologia di sintesi per tre complessi eterolettici cationici luminescenti di Ir(III), impiegando come leganti ciclometallanti un 4-fenil-1,2,3-triazolilidene e/o un 4-fenil-1,2,3-triazolo. Il legante ancillare impiegato, la 4,4’-di-tertbutil-2,2’-bipiridina, è il medesimo per tutti e tre i complessi ottenuti al fine di studiarne le proprietà fotofisiche ed elettrochimiche al variare dei leganti ciclometallanti. I complessi ottenuti sono stati caratterizzati mediante spettroscopia di Risonanza Magnetica Nucleare (NMR), per avere conferma sulla loro struttura molecolare. Si sono valutate le proprietà elettrochimiche mediante voltammetria ciclica ed a onda quadra e si è proseguito con la caratterizzazione fotofisica. Quest’ultima comprende spettri di assorbimento a 298 K, spettri di emissione con calcolo delle rese quantiche e misura dei tempi di vita in soluzione (a 298 K ed a 77 K) ed allo stato solido. La caraterizzazione sperimentale è stata supportata dai risultati di un’analisi computazionale effettuata precedentemente dal gruppo di ricerca.

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Parise, Chiara. "Complessi carbenici N-eterociclici di rutenio: catalizzatori omogenei in reazioni di idrogenazione e deidrogenazione". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9255/.

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Il presente lavoro di tesi si inserisce in un progetto di ricerca volto alla sintesi di nuovi complessi di metalli di transizione per lo sviluppo di catalizzatori bifunzionali metallo-legante da impiegare in reazioni di catalisi omogenea, in particolare in reazioni redox quali idrogenazione e deidrogenazione attraverso il trasferimento di idrogeno. Il mio progetto ha riguardato la messa a punto della sintesi di complessi di Ru(0) che combinano leganti ciclopentadienonici e carbeni N-eterociclici e la sintesi dei corrispondenti complessi cationici per protonazione. Inoltre, è stato sintetizzato e caratterizzato un nuovo complesso cationico attraverso la metilazione del corrispettivo complesso neutro. I complessi sintetizzati sono stati utilizzati come precursori di catalizzatori nella riduzione tramite trasferimento di idrogeno del 4-fluoroacetofenone, valutandone l’attività catalitica in relazione a leganti, additivi e controioni. Allo scopo di delineare qualche ipotesi sul meccanismo di reazione sono stati effettuati diversi studi sulla reattività dei complessi impiegati in catalisi, in particolare usando la piridina come agente di “trapping”. Infine, è stato condotto uno studio preliminare dell’attività catalitica dei complessi sintetizzati nell’ossidazione di benzilalcol a benzaldeide. The present work is part of a research project that involves the study of new ruthenium-based transition metal complexes in order to develop new metal-ligand bifunctional catalysts to employ in homogeneous catalytic systems, in particular in redox reactions such as hydrogenation and dehydrogenation through hydrogen transfer. My project is focused on the optimization of the synthesis of Ru(0) complexes that combines different ligands as tetraphenylcyclopentadienone and N-heterocyclic carbenes and the synthesis of the corresponding cationic complexes by protonation. Furthermore, it is reported the synthesis and characterization of a new cationic complex obtained by methylation of the corresponding neutral complex. All the prepared complexes were employed as catalyst precursors in the transfer hydrogenation of 4-fluoroacetophenone and their performances were investigated in relation to the type of ligands, additives and counterions. The reactivity of these ruthenium complexes was also investigated with the aim of delineate some hypothesis on the reaction mechanism, in particular employing pyridine as a trapping agent. Finally, preliminary studies on the oxidation of benzyl alcohol have been carried out.

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Conti, Silvia. "Nuovi complessi carbenici-N-eterociclici di argento e rutenio: il ruolo del sale di imidazolio". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/6080/.

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Il presente lavoro di tesi si inserisce in un progetto di ricerca volto alla sintesi di nuovi complessi di metalli di transizione per lo sviluppo di catalizzatori bifunzionali metallo-legante da impiegare in reazioni di catalisi omogenea come, ad esempio, l’idrogenazione di doppi legami polari. In particolare, il mio progetto ha riguardato la sintesi e la caratterizzazione di nuovi complessi carbonilici di rutenio che combinano diversi leganti quali tetrafenilciclopentadienoni e carbeni N-eterociclici. Inizialmente è stato preparato il complesso dimerico ciclopentadienonico di rutenio carbonilico dicarbonil(η4-3,4-bis(4-metossifenil)-2,5-difenilciclopenta-2,4-dienone)dimero, utilizzato come precursore in tutte le sintesi dei nuovi complessi di rutenio. Successivamente, sono stati preparati numerosi sali di imidazolio da impiegare come precursori dei leganti carbenici N-eterociclici e i corrispondenti complessi di argento. La reattività dei complessi di argento nei confronti del precursore dimerico di rutenio dicarbonil(η4-3,4-bis(4-metossifenil)-2,5-difenilciclopenta-2,4-dienone)dimero ha portato alla formazione di complessi differenti a seconda dell’ingombro sterico del legante carbenico N-eterociclico. È stato inoltre approfondito lo studio della reattività dei sali di imidazolio, variandone ingombro sterico e sostituenti, per combinazione diretta con il precursore dimerico di rutenio dicarbonil(η4-3,4-bis(4-metossifenil)-2,5-difenilciclopenta-2,4-dienone)dimero.

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Ranalli, Augusto. "Sali d'imidazolio come precursori nella sintesi di complessi ciclopentadienonici di ferro: studio della reattività in etanolo". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24361/.

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Il progetto di tesi svolto ha avuto l’obiettivo di sintetizzare alcuni complessi ciclopentadienonici di ferro neutri e ionici e studiarne la reattività in etanolo per determinare un’eventuale attività catalitica per la reazione di Guerbet. Il ferro, sebbene ampiamente utilizzato in catalisi eterogenea, è stato impiegato molto poco in quella omogenea data la sua minore attività catalitica rispetto ai “metalli nobili” come il rutenio. Tuttavia, nell'ottica di una chimica più sostenibile, la ricerca si sta focalizzando sulla catalisi condotta da complessi omogenei a base di ferro e altri metalli della prima serie di transizione. Infatti, tale metallo risulta ampiamente disponibile nella crosta terrestre ed è molto meno costoso e meno tossico, pertanto il suo utilizzo in catalisi omogenea rende i processi più competitivi. La reazione che ci si è prefissati di studiare è la reazione di Guerbet che consente di trasformare del bioetanolo, proveniente dalle biomasse di scarto, a n-butanolo. Un processo molto elegante e pulito che permette di ottenere un combustibile alternativo, nonché un composto a maggior valore aggiunto come “building block” per la sintesi di prodotti per la chimica fine. Per poter incrementare l’attività catalitica dei complessi di ferro, sono stati impiegati dei leganti ciclopentadienonici data la loro natura non-innocente nelle reazioni di ossidoriduzione. Inoltre, sono stati impiegati anche i sali d’imidazolio, impiegati tal quali o come precursori dei leganti N-eterociclici carbenici (NHC), che contribuiscono alla stabilizzazione e all’attivazione dei complessi. Pertanto, durante l’attività di tirocinio, sono stati sintetizzati cinque tipi di complessi ciclopentadienonici di ferro e, una volta caratterizzati, sono stati testati in delle prove catalitiche e di reattività nelle condizioni idonee per la reazione di Guerbet di etanolo.

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Olivieri, Diego. "Sintesi e Caratterizzazione di Elettrodi Modificati Chimicamente con nuovi complessi Carbenici del Ferro". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11891/.

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The Chemically Modified Electrodes (CME) are widely used in electroanalytical chemistry as chemical sensors. The interest in the covalent anchoring of a redox mediator on the electrode surface is increasing, because it allows the sensibility and the selectivity of this kind of systems to improve. My work is situated in this field of research and involves the synthesis of new Iron(0) complexes that contain cyclopentadienone, N-heterocyclic carbene (NHC) and carbonyl ancillary ligands. These complexes have shown electrochemical properties similar to those of ferrocene (organometallic compound widely used as electrochemical sensor). These complexes have been properly functionalized with a EDOT group in the NHC ligand side chain that it was after used for the realization of Electrochemically Modified PEDOT thanks to copolymerization reaction between the functionalized complex and the EDOT in different amounts. All the synthetic steps were assisted by suitable characterizations (NMR, IR, ESI-MS, cyclic voltammetry and X-ray for the monomeric compound as imidazolium salt and NHC functionalized complexes; cyclic voltammetry, IR e SEM for the copolymers). The properties of the polymer as a selective sensor was preliminarily investigated for dopamine and 2-propanol.

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Teti, Martina. "Valorizzazione di bioetanolo attraverso la reazione di Guerbet ad opera di catalizzatori di rutenio supportati". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19272/.

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Il presente elaborato finale si inserisce in un progetto di ricerca volto alla sintesi di nuovi complessi di metalli di transizione supportati su resine polistireniche, per lo sviluppo di catalizzatori eterogenei di Rutenio(0), da impiegare nella reazione di conversione dell’etanolo in n-butanolo e alcoli superiori, nota come la reazione di Guerbet. In particolare, il mio tirocinio si inserisce in questo ambito all’interno di una collaborazione fra il gruppo di chimica metallorganica e quello di reattori e catalisi (Prof. Cavani) ed ha riguardato in primo luogo la sintesi e la caratterizzazione di un complesso di Rutenio(0) con leganti non-innocenti quali il ciclopentadienone e carbeni-N-eterociclici. L’attività catalitica del complesso omogeneo è stata valutata nella reazione di Guerbet. Il complesso di Rutenio è stato successivamente supportato su resine polistireniche consentendo così una separazione del prodotto semplificata e la possibilità di recuperare e riutilizzare il catalizzatore. Questa metodologia di sintesi è volta a combinare i benefici della catalisi omogenea con quelli della catalisi eterogenea. I campioni solidi preparati con questa tecnologia, sono stati caratterizzati mediante spettroscopia IR-ATR e ICP, ed infine l’attività catalitica dei composti supportati e la loro riciclabilità è stata valutata nella reazione di Guerbet.

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Sau, Roca Míriam. "From Click Chemistry to catalytic cleavage of unstrained C-C bonds". Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/396080.

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Aquesta tesi doctoral es basa principalment amb la síntesis de molècules petites potencialment útils per investigacions avançades. S'han utilitzat diferents metodologies per obtenir-les: 1) Cicloaddicions intramoleculars entre un alkí i una azida lliures de coure per l'obtenció de derivats de benzodiazepines. Obtenint-se una gran varietat de triazols fusionats a heterocicles de set membres. Posteriorment, s'han dut a terme proves d'activitat biològica. 2) a) Trencament d'enllaços carboni-carboni no activats d'amino alcohols i utilització d'aquest com a nucleòfil juntament amb bromurs d'aril en una reacció d'acoplament catalitzada per pal.ladi per l'obtenció de dibenzil amines. S'ha dut a terme una gran optimització dels diferents paràmetres de reacció; base, dissolvent, electròfil, temperatura, catalitzador i lligand. b) Trencament d'enllaços carboni-carboni no activats de N-alil amino alcohols i utilització d'aquest com a nucleòfil juntament amb bromurs d'aril en una reacció d'acoplament catalitzada per pal.ladi per l'obtenció d'aldehids arilats en la posició beta. S'ha dut a terme la síntesis d'un gran nombre d' amino alcohols nous i aquests han estat sotmesos a les condicions optimitzades de reacció. Demostrant que aquest transformació és útil per un gran ventall de substrats (bromurs d'aril i amino alcohols).L'enamina resultant de la reacció d'acoplament s'ha aconseguit alquilar amb vinil metil cetona amb bons rendiments però pobres diastereoselectivitats tot i així s'ha demostrant que la reacció és factible. Per finalitzar, s'ha aconseguit desenvolupar la versió enantioselectiva de l’anterior transformació obtenint bons excessos enantiomerics tot i que baixos rendiments.
Ésta tesis doctoral está basada principalmente en la síntesis de moléculas pequeñas potencialmente útiles para investigaciones avanzadas. Se han empleado diferentes metodologías para obtenerlas: 1) Cicloadiciones intramoleculares entre un alkino y una azida libres de cobre para la obtención de derivados de benzodiazepinas. Se han obtenido una gran variedad de triazoles fusionados a heterociclos de siete miembros. Posteriormente se han realizado pruebas de actividad biológica de las moléculas resultantes. 2) a) Escisión de enlaces carbono-carbono no activados de amino alcoholes y utilitzación de éstos como nucleófilos conjuntamente con bromuros de arilo para una reacción de acoplamiento catalizada por paladio para la obtención de derivados de dibenzil aminas. Se ha realizado una gran optimización de las condiciones de reacción; base, disolvente, electrófilo, temperatura, catalizador y ligando. b) Escisión de enlaces carbono-carbono no activados de N-alilo amino alcoholes y la utilización de éste como nucleófilo conjuntamente con bromuros de arilo en una reacción de acoplamiento catalizada por paladio para la obtención de aldehídos arilados en posición beta. Se ha realizado la síntesis de un gran numero de amino alcoholes nuevos y éstos se han sometido a las condiciones optimizadas de reacción. Demostrando que ésta transformación es útil para una gran variedad de sustratos (bromuros de arilo y amino alcoholes). La enamina resultante de la reacción de acoplamiento se ha alquilado con vinil metil cetona con buenos rendimientos pero pobres diastereoselectividades aunque se ha demostrado que la reacción es factible. Para finalizar, se ha desarrollado la versión enantioselectiva de la anterior transformación obteniendo buenos excesos enantioméricos aunque con bajos rendimientos.
This PhD thesis is based basically on synthesis of small molecules potentially useful for further investigations. Different strategies have been used to obtain them; 1) Copper free intramolecular cycloadditions between an azide and an akyne for the obtention of benzodiazepine derivatives. A wide range of triazoles fused to seven membered heterocycles rings have been obtained. Later, biological studies have been carried out. 2)a) Carbon-carbon bond cleavage of amino alcohols has been carried out with the subsequent use of them as a nucleophile together with aryl bromides to develop a cross-coupling reaction for the obtention of dibenzyl amines. A wide optimization of the reaction parameters was carried out; base, ligand, catalyst, electrophile, temperatura, and solent. b) Carbon-carbon bond cleavage of N- allyl amino alcohols has been carried out with the subsequent use of them as a nucleophile together with aryl bromides to develop a cross-coupling reaction for the obtention of beta arylated aldehydes. An important number of new amino alcohols have been synthesized and these have been subjected to the optimized reaction conditions. It has been demonstrated that this transformation is useful for a wide range of substrates (amino alcohols and aryl bromides). The resultant enamine has been alkylated with methyl vinyl ketone with good yields but poor diastereoselectivity. To finish the enantioselective version of beta functionalization of aldehydes has been developed obtaining good enantioselectivity but poor yields

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Libros sobre el tema "Carbeni"

Furimsky, Edward. Carbons and carbon-supported catalysts in hydroprocessing. Cambridge, UK: Royal Society of Chemistry, 2008.

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T, Hill John, ed. Walker Evans: Argento e carbone = carbon and silver. Firenze: Alinari, 2005.

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1940-, Aresta M., Schloss J. V, NATO Advanced Study Institute y North Atlantic Treaty Organization. Scientific Affairs Division., eds. Enzymatic and model carboxylation and reduction reactions for carbon dioxide utilization. Dordrecht: Kluwer Academic Publishers, 1990.

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Farrell, Michael A. Highly polarisable derivatives of bridging carbene and carbyne di-iron complexes. Dublin: University College Dublin, 1998.

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Vercammen, James. Dynamic economic modeling of soil carbon. [Ottawa]: Agriculture and Agri-Food Canada, 2002.

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Fischer, H., ed. Conjugated Carbon Centered Radicals, High-Spin System and Carbenes. Berlin/Heidelberg: Springer-Verlag, 2002. http://dx.doi.org/10.1007/b79545.

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Carbon-Capture by Metal-Organic Framework Materials. Millersville, PA: Materials Research Forum LLC, 2020.

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M, Meyyappan, ed. Carbon nanotubes: Science and applications. Boca Raton, FL: CRC Press, 2005.

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Electroanalysis with carbon paste electrodes. Boca Raton: Taylor & Francis, 2012.

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Canada, Canada Natural Resources y Canadian Forest Service, eds. Canada's forest carbon budget = Bilan du carbone des forêts du Canada. [Ottawa]: Canadian Forest Service, 2001.

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Capítulos de libros sobre el tema "Carbeni"

Pruchnik, Florian P. y Stan A. Duraj. "Carbene and Carbyne Complexes". En Organometallic Chemistry of the Transition Elements, 277–326. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4899-2076-8_5.

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Roussak, O. V. y H. D. Gesser. "Carbon-Based Polymers, Activated Carbons". En Applied Chemistry, 279–90. Boston, MA: Springer US, 2012. http://dx.doi.org/10.1007/978-1-4614-4262-2_16.

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Busetto, L., V. Zanotti, S. Bordoni, L. Carlucci y A. Palazzi. "Carbyne to Carbene Ligand Conversion in Dinuclear Complexes". En Transition Metal Carbyne Complexes, 137–47. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1666-4_17.

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Lukehart, C. M. "Carbyne Complexes by Deprotonation of Cationic Carbene Complexes". En Inorganic Reactions and Methods, 222–24. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470145265.ch27.

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Hatta, Hiroshi, Roland Weiss y Patrick David. "Carbon/Carbons and their Industrial Applications". En Ceramic Matrix Composites, 85–146. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118832998.ch5.

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Lu, An-Hui, Guang-Ping Hao y Xiang-Qian Zhang. "Porous Carbons for Carbon Dioxide Capture". En Green Chemistry and Sustainable Technology, 15–77. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-54646-4_2.

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Kocsis, Ashley y Steven W. Cranford. "Carbyne: A One-Dimensional Carbon Allotrope". En Carbon Nanomaterials Sourcebook, 3–25. Boca Raton : Taylor & Francis Group, 2016. | “A CRC title.” |: CRC Press, 2018. http://dx.doi.org/10.1201/9781315371337-1.

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Gordon, F. y A. Stone. "Carbyne to Carbene Conversion Reactions at Heteronuclear Dimetal Centres". En Advances in Metal Carbene Chemistry, 11–25. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2317-1_2.

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Boucif, Noureddine, Denis Roizard y Eric Favre. "The Carbonic Anhydrase Promoted Carbon Dioxide Capture". En Environmental Chemistry for a Sustainable World, 1–44. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-33978-4_1.

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Charnley, Steven B. "Carbene". En Encyclopedia of Astrobiology, 356. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-44185-5_222.

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Actas de conferencias sobre el tema "Carbeni"

Thaddeus, Patrick. "Carbenes in the Interstellar Gas". En High Resolution Spectroscopy. Washington, D.C.: Optica Publishing Group, 1993. http://dx.doi.org/10.1364/hrs.1993.tha1.

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Carbenes are a significant trace constituent of the gas in the interstellar medium (and in the expanding shell around at least one star), representing about one-sixth of the molecular species that have been identified in space. The identification of one of the most abundant and widespread interstellar carbenes, the cyclopropenylidene ring, C3H2, is described, together with recent laboratory work on the excited vibrational states of this molecule and on the geometrical structure of one of its isomers, the carbon chain carbene H2C3. A number of additional free carbines which might be detected in space are considered. There are at least two reasons why carbenes are comparatively conspicuous in astronomical sources relative to other reactive molecules: one is their high polarity; a second is their production via the same ion-molecule reactions that make known stable species in space (or very similar reactions). Finally, it is pointed out that cumulene carbon chains somewhat longer than those so far detected in space are promising candidates for the carriers of the interstellar optical diffuse bands.

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Danno, T. "XPS Study of Carbyne-Like Carbon Films". En ELECTRIC PROPERTIES OF SYNTHETIC NANOSTRUCTURES: XVII International Winterschool/Euroconference on Electronic Properties of Novel Materials. AIP, 2004. http://dx.doi.org/10.1063/1.1812123.

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Guseva, M. B., V. M. Babina, M. Boustie, Vladimir E. Fortov, J. P. Romain, A. Z. Zhuk, V. G. Babaev y V. V. Khvostov. "Synthesis of carbyne from amorphous line-chain carbon and pyrographite". En Lasers in Synthesis, Characterization, and Processing of Diamond, editado por Vitali I. Konov y Victor G. Ralchenko. SPIE, 1998. http://dx.doi.org/10.1117/12.328213.

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Alavian, Sayyed Ahmad y Curtis Hays Whitson. "Modeling CO2 Injection Including Diffusion in a Fractured-Chalk Experiment with Initial Water Saturation". En Carbon Management Technology Conference. Carbon Management Technology Conference, 2012. http://dx.doi.org/10.7122/149976-ms.

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Yang, Yuelei y Mark Malchiondo. "Design and Analysis of a Smart Energy Management System for Residential and Industrial Buildings". En Carbon Management Technology Conference. Carbon Management Technology Conference, 2012. http://dx.doi.org/10.7122/151358-ms.

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Tao, Qing y Steven Lawrence Bryant. "Optimal Control of Injection/Extraction Wells for the Surface Dissolution CO2 Storage Strategy". En Carbon Management Technology Conference. Carbon Management Technology Conference, 2012. http://dx.doi.org/10.7122/151370-ms.

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Garnham, Paul Jonathan y Owain David Tucker. "The Longannet to Goldeneye Project: Challenges in Developing an End-to-End CCS Scheme". En Carbon Management Technology Conference. Carbon Management Technology Conference, 2012. http://dx.doi.org/10.7122/151716-ms.

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Jiang, Xanglin y Qingbin Cui. "Carbon Policy and Its Impact on Construction Firms". En Carbon Management Technology Conference. Carbon Management Technology Conference, 2012. http://dx.doi.org/10.7122/151721-ms.

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Tang, Robert E. y Anupam Sanyal. "An Innovative and Cost Effective CO2 Capture Technology". En Carbon Management Technology Conference. Carbon Management Technology Conference, 2012. http://dx.doi.org/10.7122/149808-ms.

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Mohamed, Ibrahim Mohamed, Jia He y Hisham A. Nasr-El-Din. "Carbon Dioxide Sequestration in Sandstone Aquifers: How Does It Affect the Permeability?" En Carbon Management Technology Conference. Carbon Management Technology Conference, 2012. http://dx.doi.org/10.7122/149958-ms.

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Informes sobre el tema "Carbeni"

Lee, Samkeun y John Cooper. Highly Reduced Carbene Complexes: Formation of an Alkoxymalonate by Coupling of Carbon Dioxide with the Nucleophilic Carbene in (Cr(CO4)=C(OMe)PH)2-. Fort Belvoir, VA: Defense Technical Information Center, noviembre de 1989. http://dx.doi.org/10.21236/ada215132.

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Cooper, J. F., N. Cherepy, R. Upadhye, A. Pasternak y M. Steinberg. Direct Carbon Conversion: Review of Production and Electrochemical Conversion of Reactive Carbons, Economics and Potential Impact on the Carbon Cycle. Office of Scientific and Technical Information (OSTI), diciembre de 2000. http://dx.doi.org/10.2172/15007473.

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Hoffman, Wesley P. How Well Does Carbon Handle Stress? - A Brief Overview of Carbons in Structural Applications. Fort Belvoir, VA: Defense Technical Information Center, junio de 2004. http://dx.doi.org/10.21236/ada425702.

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Gold, Phillip I. Electrical Resistivity of Carbon-Carbon Composites,. Fort Belvoir, VA: Defense Technical Information Center, febrero de 1988. http://dx.doi.org/10.21236/ada193006.

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Jones, William D. Transition Metal Activation And Functionalization Of Carbon-Hydrogen And Carbon-Carbon Bonds. Office of Scientific and Technical Information (OSTI), octubre de 2019. http://dx.doi.org/10.2172/1569760.

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Schmidt, Donald L. Carbon-Carbon Composites (CCC) - A Historical Perspective. Fort Belvoir, VA: Defense Technical Information Center, septiembre de 1996. http://dx.doi.org/10.21236/ada325314.

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Haack, David P. Scale-up of Carbon/Carbon Bipolar Plates. Office of Scientific and Technical Information (OSTI), abril de 2009. http://dx.doi.org/10.2172/950868.

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Koo, J. H., L. A. Pilato, C. U. Pittman, Winzek Jr. y P. Nanomodified Carbon/Carbon Composites for Intermediate Temperature. Fort Belvoir, VA: Defense Technical Information Center, enero de 2004. http://dx.doi.org/10.21236/ada419919.

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Dresselhaus, M. S. y J. Steinbeck. Liquid Carbon. Fort Belvoir, VA: Defense Technical Information Center, octubre de 1987. http://dx.doi.org/10.21236/ada191707.

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Wang, H. y R. B. Dinwiddie. Thermal diffusivity mapping of 4D carbon-carbon composites. Office of Scientific and Technical Information (OSTI), marzo de 1997. http://dx.doi.org/10.2172/446404.

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