Stable ion and electrophilic chemistry of fluoranthene-PAHsElectronic supplementary information (ESI) available: Table S1, NMR spectra and results of calculations. See http://www.rsc.org/suppdata/p2/b1/b108025n/

Laali, Kenneth K.; Okazaki, Takao; Galembeck, Sérgio E.

doi:10.1039/b108025n

Cited by 12 publications

(10 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To support this conjecture, we quenched the reaction of 3a 2þ and were able to identify starting material 3a as well as downfield peaks that were consistent with the formation of the substituted benz-[e]acephenathrylene 25 (see the Supporting Information).…”

Section: Evaluation Of Antiaromaticity Through Magnetic Measuresmentioning

confidence: 99%

Dications of Benzylidenefluorene and Diphenylmethylidene Fluorene: The Relationship between Magnetic and Energetic Measures of Antiaromaticity

Hatfield

Patel

et al. 2010

J. Org. Chem.

View full text Add to dashboard Cite

Oxidation of m-and p-substituted benzylidene fluorenes to antiaromatic dications was attempted by electrochemical and chemical means. Electrochemical oxidation to dications was successful for benzylidene fluorenes with p-methoxy, p-methyl, p-fluoro, and unsubstituted phenyl rings in the 3-position; attempts to oxidize the m-substituted derivatives via electrochemistry were unsuccessful. Chemical oxidation with SbF 5 /SO 2 ClF gave the dication of 9-[(4-methoxyphenyl)methylene]-9H-fluorene cleanly; oxidation of all other substituted benzylidene fluorenes resulted in mixtures of products. The excellent linear relationship between the chemical shifts calculated by the GIAO method and the experimental shifts for the p-methoxy-substituted benzylidene fluorene dication suggests that the calculations satisfactorily reflect the magnetic properties of this dication and potentially those of the other dications studied. The redox potentials from electrochemical oxidation, a measure of the stability of the dications, showed a good linear relationship with another measure of stability, the calculated difference in energy between each dication and its neutral precursor. The dications of benzylidene fluorenes were less stable than the dications of diphenylmethylidene fluorenes; within each type of compound, dications with p-substituted phenyl rings were more stable than dications with m-substituted phenyl rings and dications with phenyl rings substituted with electron-donating groups were more stable than dications with phenyl rings substituted with electron-withdrawing groups. The antiaromaticity of the fluorenyl system was assessed through the nucleus-independent chemical shift (NICS) that was also calculated by the GIAO method. The plot of the NICS values per square area versus the calculated energy difference for the dications showed a moderate degree of linearity; the plot of NICS values per square area versus the oxidation potentials was less linear. Thus, a suggestive, but not conclusive, relationship between magnetic and energetic measures of antiaromaticity was observed.

show abstract

Section: Evaluation Of Antiaromaticity Through Magnetic Measuresmentioning

confidence: 99%

Dications of Benzylidenefluorene and Diphenylmethylidene Fluorene: The Relationship between Magnetic and Energetic Measures of Antiaromaticity

Hatfield

Patel

et al. 2010

J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…Nonalternant PAH cations with a five‐membered π‐ring are expected to be potential candidates to have anti‐aromaticity. Fluoranthene ( 1 ), which is one of nonalternant polycyclic aromatic hydrocarbons, ionized in FSO 3 H/SO 2 ClF to produce 3‐protonated fluoranthene ( 1H + ) (Figure ) . Benzo[ b ]fluoranthene ( 2 ) was protonated at C(1) to give 2H + in FSO 3 H/SO 2 ClF .…”

Section: Introductionmentioning

confidence: 99%

“…The aromaticity of PAHs is more complicated. Each of cyclic π‐rings has been elucidated to have intrinsic local aromaticity/anti‐aromaticity . PAHs usually display local aromaticity with six π‐electrons localized at certain benzenoid rings.…”

Section: Introductionmentioning

confidence: 99%

“…PAHs usually display local aromaticity with six π‐electrons localized at certain benzenoid rings. Some cations of cyclopentadiene‐fused PAHs, such as the 9‐fluorenyl and the indenyl (benzocyclopentadienyl) cations, have local anti‐aromaticity in the cyclopentadienyl ring …”

Section: Introductionmentioning

confidence: 99%

“…Fluoranthene ( 1 ), which is one of nonalternant polycyclic aromatic hydrocarbons, ionized in FSO 3 H/SO 2 ClF to produce 3‐protonated fluoranthene ( 1H + ) (Figure ) . Benzo[ b ]fluoranthene ( 2 ) was protonated at C(1) to give 2H + in FSO 3 H/SO 2 ClF . Their experimental NMR observation and NICS (nucleus‐independent chemical shifts) values obtained by DFT (density functional theory) calculations indicated anti‐aromaticity of the five‐membered ring.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Charge delocalization mode and change in aromaticity of protonated 7‐phenylbenzo[k]fluoranthenes studied by experimental observation and DFT calculations

Okazaki

Matsunaga

Kitagawa

2019

J of Physical Organic Chem

Self Cite

View full text Add to dashboard Cite

7‐Phenylbenzo[k]fluoranthene (4), which is one of non‐alternant polycyclic aromatic hydrocarbons, was protonated at the C(12) position in neat CF3SO3H to give a persistent carbocation (4aH+). The cation was successfully observed by NMR measurements at rt. The most deshielded protons were observed as doublet signals at 8.92 and 8.71 ppm for H(1) and H(3). The most deshielded 13C signals appeared at 184.4 and 176.6 ppm for C(12a) and C(7). The positive charge was found to be delocalized to four carbons in a 1‐naphthalenium unit and to two other carbons according to Δδ13C from 4 to 4aH+. DFT calculations indicated that 4aH+ was the most stable among possible protonation carbocations. The NICS(1)zz values of 4aH+ suggested that the five‐membered π‐ring is nonaromatic and that the other benzenoid rings are aromatic. The influence of the 7‐phenyl group on aromaticity and on positive charge delocalization was limited. The next most stable cations were computed to be cations (4bH+ and 4cH+) that were generated by the protonation at the C(3) and C(4) positions, respectively. Their Gibbs energies were similar within 0.7 kcal/mol to that of 4aH+. Their five‐membered π‐rings were proved to be anti‐aromatic according to the NICS(1)zz criteria. 4bH+ and 4cH+ can be depicted by canonical structures with a cyclopentadienyl cation unit, which is suggested to be responsible for their anti‐aromaticity.

show abstract

2,7,11,16‐Tetra‐tert‐Butyl Tetraindenopyrene Revisited by an “Inverse” Synthetic Approach

Elbert

Haidisch

Kirschbaum

et al. 2020

Chemistry A European J

View full text Add to dashboard Cite

A new synthetic route to tetraindenopyrene (TIP)—a bowl‐shaped cut‐out structure of C70—is reported. The key step in this approach is a fourfold palladium‐catalyzed C−H activation that increases the yield more than 50 times in comparison to the approach originally described by Scott and co‐workers. Besides examination of its optoelectronic properties and study of its aggregation in solution, TIP was also re‐investigated by dispersion‐corrected DFT methods, which showed that dispersion interactions significantly increase the bowl‐to‐bowl inversion barrier. Furthermore, TIP was used as a semiconductor in p‐channel thin‐film transistors (TFTs).

show abstract

Stable ion and electrophilic chemistry of fluoranthene-PAHsElectronic supplementary information (ESI) available: Table S1, NMR spectra and results of calculations. See http://www.rsc.org/suppdata/p2/b1/b108025n/

Cited by 12 publications

References 31 publications

Dications of Benzylidenefluorene and Diphenylmethylidene Fluorene: The Relationship between Magnetic and Energetic Measures of Antiaromaticity

Dications of Benzylidenefluorene and Diphenylmethylidene Fluorene: The Relationship between Magnetic and Energetic Measures of Antiaromaticity

Charge delocalization mode and change in aromaticity of protonated 7‐phenylbenzo[k]fluoranthenes studied by experimental observation and DFT calculations

2,7,11,16‐Tetra‐tert‐Butyl Tetraindenopyrene Revisited by an “Inverse” Synthetic Approach

Contact Info

Product

Resources

About