Superelectrophiles: Charge–Charge Repulsive Effects

Klumpp, Douglas A.

doi:10.1002/chem.200701470

Cited by 45 publications

(52 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It could be noted that C α protonation was increasingly favored, as the C α –C β bond became longer, i.e., as the ylid form became more stabilized by conjugation with the β ‐substituent. In accord with Olah's definition,38–40 the resulting charge separated carbenium/diazonium dications represent new examples of distonic superelectrophiles.…”

Section: Resultsmentioning

confidence: 82%

A computational study (DFT, MP2, and GIAO‐DFT) of substituent effects on protonation regioselectivity in β,β‐disubstituted vinyldiazonium cations: formation of highly delocalized carbenium/diazonium dications

Borosky

Laali

2009

J of Physical Organic Chem

View full text Add to dashboard Cite

A computational study (DFT, MP2, and GIAO-DFT) of substituent effects on protonation regioselectivity in b,b-disubstituted vinyldiazonium cations: formation of highly delocalized carbenium/ diazonium dications Protonation reactions were studied by quantum-chemical theoretical methods (DFT and MP2) for a series of b,b-disubstituted vinyldiazonium cations (1 R -14 R ), bearing stabilizing electron-releasing groups (H 3 COÀ, (H 3 C) 2 NÀ, H 3 CÀ, (H 3 C) 3 SiÀ, as well as halogens F, Cl). Taking into account the various mesomeric forms that these species can represent, protonations at C a , at the b-substituent, and at N b were considered. The energetically most favored pathway in all cases was C a protonation, which formally corresponds to trapping of the mesomeric diazonium ylid. Based on the computed properties (optimized geometries, NPA-charge densities, and multinuclear GIAO-NMR chemical shifts), the resulting dications can best be viewed as carbenium/diazonium dications, in which the carbocation is further delocalized into the b-substituent. For the a-nitro derivative 15, protonation of the nitro group was predicted to be the most favored reaction, while C a -and N b -protonation resulted in the loss of the nitronium ion.Vinyldiazonium ions are viable precursors to vinyl cations via the dediazoniation route. [23,24] Early progress on solvolytic generation of vinyl cations by deamination of suitable substituted (www.interscience.wiley.com)

show abstract

Section: Resultsmentioning

confidence: 82%

A computational study (DFT, MP2, and GIAO‐DFT) of substituent effects on protonation regioselectivity in β,β‐disubstituted vinyldiazonium cations: formation of highly delocalized carbenium/diazonium dications

Borosky

Laali

2009

J of Physical Organic Chem

View full text Add to dashboard Cite

show abstract

“…35 According to Olah's definition of superelectrophiles, under superacidic conditions, further protonation or protosolvation of the protonated aldehydes or ketones is possible, which leads to very reactive intermediates (superelectrophiles), that is, electrophiles of doubly electron-deficient (dipositive) nature whose reactivity significantly exceeds that of their parent monocations under conventional reaction conditions. [36][37][38] This super-electrophilic or multi-ionic intermediate can undergo successive condensation reactions with weaker nucleophiles, and thus it is possible the reaction even with deactivated aromatic rings (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Microporous Polymer Networks for Carbon Capture Applications

Lopez-Iglesias

Suárez-Garcı́a

Aguilar‐Lugo

et al. 2018

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

A new generation of porous polymer networks has been obtained in quantitative yield by reacting two rigid trifunctional aromatic monomers (1,3,5-triphenylbenzene and triptycene) with two ketones having electron-withdrawing groups (trifluoroacetophenone and isatin) in superacidic media. The resulting amorphous networks are microporous materials, with moderate Brunauer-Emmett-Teller surface areas (from 580 to 790 m g), and have high thermal stability. In particular, isatin yields networks with a very high narrow microporosity contribution, 82% for triptycene and 64% for 1,3,5-triphenylbenzene. The existence of favorable interactions between lactams and CO molecules has been stated. The materials show excellent CO uptakes (up to 207 mg g at 0 °C/1 bar) and can be regenerated by vacuum, without heating. Under postcombustion conditions, their CO/N selectivities are comparable to those of other organic porous networks. Because of the easily scalable synthetic method and their favorable characteristics, these materials are very promising as industrial adsorbents.

show abstract

“…971,972 A rare example of cationic polymerization of emulsified epoxy resins has been reported by Walker et al 973 Polymerization of water emulsion of epoxy resins with a variety of superacids (triflic acid, HClO 4 , HBF 4 , HPF 6 ) results in polyols with two glycidyl units (294) in contrast to commercial epoxy resins with one unit separating the aromatic moieties. Crivello and Lam 970 were the first to report that diaryliodonium salts undergo photodecomposition to generate Brønsted superacids (Scheme 5.99), which are capable of initiating the polymerization of suitable monomers.…”

Section: Polymerizationmentioning

confidence: 99%