Thermochemical Studies of Epoxides and Related Compounds

Morgan, Kimberly J.; Ellis, Jamie A.; Lee, Joseph; Fulton, Ashley; Wilson, Shavonda L.; Dupart, Patrick S.; Dastoori, Rosanna

doi:10.1021/jo4002867

Cited by 47 publications

(37 citation statements)

References 31 publications

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“…For example, epoxide groups present in GO are particularly unstable and likely to react, due to the inductive effect of the oxygen and the unfavourable ring strain. 45 This may contribute to the observed hole formation (Fig. 4) in the GO sheets [16][17][18] where epoxides arise.…”

mentioning

confidence: 95%

Hypochlorite degrades 2D graphene oxide sheets faster than 1D oxidised carbon nanotubes and nanohorns

et al. 2017

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Carbon nanostructures are currently fuelling a revolution in science and technology in areas ranging from aerospace engineering to electronics. Oxidised carbon nanomaterials, such as graphene oxide, exhibit dramatically improved water dispersibility compared to their pristine equivalents, allowing their exploration in biology and medicine. Concomitant with these potential healthcare applications, the issue of degradability has been raised and has started to be investigated. The aim of the present study was to assess the potential of hypochlorite, a naturally occurring and industrially used ion, to degrade oxidised carbon nanomaterials within a week. Our main focus was to characterise the physical and chemical changes that occur during degradation of graphene oxide compared to two other oxidised carbon nanomaterials, namely carbon nanotubes and carbon nanohorns. The kinetics of degradation were closely monitored over a week using a battery of techniques including visual observation, UV-Vis spectroscopy, Raman spectroscopy, infra-red spectroscopy, transmission electron microscopy and atomic force microscopy. Graphene oxide was rapidly degraded into a dominantly amorphous structure lacking the characteristic Raman signature and microscopic morphology. Oxidised carbon nanotubes underwent degradation via a wall exfoliation mechanism, yet maintained a large fraction of the sp 2 carbon backbone, while the degradation of oxidised carbon nanohorns was somewhat intermediate. The present study shows the timeline of physical and chemical alterations of oxidised carbon nanomaterials, demonstrating a faster degradation of 2D graphene oxide sheets compared to 1D oxidised carbon nanomaterials over 7 days in the presence of an oxidising species.

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confidence: 95%

Hypochlorite degrades 2D graphene oxide sheets faster than 1D oxidised carbon nanotubes and nanohorns

et al. 2017

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“…Given that relief of ring strain is the driving force for the formal homo‐Nazarov cyclization, it is conceivable that similar ring‐opening cyclization would be possible if the cyclopropane ( E strain =27.5 kcal mol −1 ) were replaced with other polarizable ring systems. In that regard, the prime candidates to probe this hypothesis include: cyclopropenes ( E strain =54 kcal mol −1 ); epoxides ( E strain =26.3 kcal mol −1 ); aziridines ( E strain =26.7 kcal mol −1 ); alkylidene cyclopropanes ( E strain =39.5 kcal mol −1 ); and cyclobutanes ( E strain =26 kcal mol −1 ).…”

Section: Substrate‐based Dos Approachesmentioning

confidence: 99%

The Catalytic, Formal Homo‐Nazarov Cyclization as a Template for Diversity‐Oriented Synthesis

Martín

Shenje

2016

Israel Journal of Chemistry

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Since the formal characterization of diversity‐oriented synthesis (DOS), identification of effective examples of DOS remains an important endeavor for synthetic and pharmaceutical chemists requiring new strategies to generate broader skeletal diversity. Over the last decade, the formal homo‐Nazarov cyclization has been an increasingly popular strategy for the concise assembly of functionalized six‐membered rings due to the advent of catalytic methods to promote the transformation under milder reaction conditions. Moreover, using the formal homo‐Nazarov cyclization as a mechanistic template, reactions can be strategically devised as an effort towards diversity‐oriented synthesis. The resulting “homo‐Nazarov‐inspired” reactions are then demonstrated as a means to access broad structural diversity. This review discusses the development of these catalytic approaches and the successful implementation of the formal homo‐Nazarov reaction as a viable template for diversity‐oriented synthesis.

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“…It is now acknowledged that measured enthalpy of formation data on species with three-membered rings of any type are simultaneously few in number 1 and reliability is occasionally suspect. 2 Likewise, measured proton affinities are almost totally absent for these species. Paralleling our recent publication, 3 using cyclopropanone (1), aziridine (2), and oxirane (3) as archetypes, the assembled species for our current study are shown in Fig.…”

Section: Introductionmentioning

confidence: 97%

“…2 Likewise, measured proton affinities are almost totally absent for these species. Paralleling our recent publication, 3 using cyclopropanone (1), aziridine (2), and oxirane (3) as archetypes, the assembled species for our current study are shown in Fig. 1: aziridine-2-one (also called ␣-lactam, 4), oxirane-2-one (also called ␣-acetolactone, 5), 1,2-diaziridine-3-one (6), 1,2-dioxirane-3-one (also called carbon trioxide, 7), 1,2-oxaziridine-3-one (8), cyclopropane-1,2-dione (9), aziridine-2,3-dione (also called oximide, 10), and oxirane-2,3-dione (also called oxalic anhydride, 11); we recently also studied the associated enol tautomers such as the two rotamers of 2-hydroxycyclopropenol (9a) corresponding to cyclopropane-1,2-dione (9).…”

Section: Introductionmentioning

confidence: 97%

Protonated heterocyclic derivatives of cyclopropane and cyclopropanone: classical species, alternate sites, and ring fragmentation

et al. 2015

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A computational study has been performed for protonated oxygen-or nitrogen-containing heterocyclic derivatives of cyclopropane and cyclopropanone. We have searched for the most stable conformations of the protonated species using density functional theory with the B3LYP functional and the 6-31G(2df,p) basis set. More accurate enthalpy values were obtained from G4 calculations. Proton affinities and gas-phase basicities were accordingly derived.Résumé : Nous avons réalisé une étude de modélisation sur des dérivés hétérocycliques protonés du cyclopropane ou de la cyclopropanone contenant un atome d'oxygène ou d'azote. Nous avons recherché les conformations les plus stables au moyen de la théorie de la fonctionnelle de la densité, en utilisant la fonctionnelle B3LYP et la base 6-31G(2df,p). La meilleure exactitude des valeurs d'enthalpie a été obtenue grâce aux calculs selon le modèle G4. De ces résultats ont été dérivées les affinités protoniques et les basicités en phase gazeuse. [Traduit par la Rédaction]Mots-clés : dérivés protonés du cyclopropane et de la cyclopropanone, enthalpie, énergie de Gibbs, affinité protonique, basicité en phase gazeuse, théorie quantique des atomes dans les molécules.

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Thermochemical Studies of Epoxides and Related Compounds

Cited by 47 publications

References 31 publications

Hypochlorite degrades 2D graphene oxide sheets faster than 1D oxidised carbon nanotubes and nanohorns

Hypochlorite degrades 2D graphene oxide sheets faster than 1D oxidised carbon nanotubes and nanohorns

The Catalytic, Formal Homo‐Nazarov Cyclization as a Template for Diversity‐Oriented Synthesis

Protonated heterocyclic derivatives of cyclopropane and cyclopropanone: classical species, alternate sites, and ring fragmentation

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