Dodecaphenyltetracene

Xiao, Yonglong; Mague, Joel T.; Schmehl, Russell H.; Haque, Farihah M.; Pascal, Robert A.

doi:10.1002/anie.201812418

Cited by 49 publications

(46 citation statements)

References 14 publications

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“…Carbon-carbon (C À C) covalent bonds represent the most fundamental concept in organic chemistry.E lucidation of their nature is of great importance for further understanding of chemical phenomena;f or instance,t ou nderstand what happens at the limits of ab ond. Since deviation from the standard causes al arge loss of bonding energy,s tructural parameters such as bond length and bond angle are nearly constant among carbon atoms.H owever, strained molecules such as sterically congested polycyclica romatic hydrocarbons [1][2][3][4][5][6][7][8] as well as cyclic p-conjugated compounds [9][10][11][12][13][14][15] exhibit unusual parameters,a nd thus have attracted much attention due to their potential applications.W ith regard to the C À C single bond, which has as tandard length of 1.54 ,t hree approaches have been taken to increase the bond length in neutral organic compounds to beyond 1.7 :( i) diamondoid dimers, [16] (ii)f used or clamped hexaphenylethanes (HPEs), [17][18][19] and (iii)d iaminocarboranes (Figure 1). [20] Among these,w ef ocused on the second approach (ii)w hile adopting the core-shell strategy,w hich enables the isolation of stable dispiro[dibenzocycloheptatriene (DBCHT)]-type HPEs 1 with an extremely elongated C(sp 3 )ÀC(sp 3 )b ond [1.806(2) for 1cat 400 K].W eenvisaged that such a"hyper covalent bond" should be weak enough to exhibit reversible expansion, contraction, formation, and scission, which could be visualized by X-ray analyses.…”

Section: Introductionmentioning

confidence: 99%

Flexible C−C Bonds: Reversible Expansion, Contraction, Formation, and Scission of Extremely Elongated Single Bonds

2020

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Since carbon-carbon (C À C) covalent bonds are rigid and robust, the bond length is,ingeneral, nearly constant and depends only on the bond order and hybrid orbitals.W e report herein direct visualization of the reversible expansion and contraction of aC (sp 3)ÀC(sp 3)s ingle bond by light and heat. This flexibility of aC À Cb ond was demonstrated by X-ray analysis and Raman spectroscopyo fh exaphenylethane (HPE)-type hydrocarbons with two spiro-dibenzocycloheptatriene units,t he intramolecular [2+ +2] photocyclization of which and thermal cleavage of the resulting cyclobutane ring both occur in as ingle-crystalline phase.T he force constant of the contracted CÀCb ond is 1.6 times greater than that of the expanded bond. Since formation of the cyclobutane ring and contraction of the C À Cb ond lower the HOMO level by approximately 1eV, the oxidative properties of these HPEs with aflexible CÀCbond can be deactivated/activated by light/ heat.

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Section: Introductionmentioning

confidence: 99%

Flexible C−C Bonds: Reversible Expansion, Contraction, Formation, and Scission of Extremely Elongated Single Bonds

2020

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“…This molecule is taken from a synthesis performed by Xiao et al Its complexity, along with the fact the team had reported a UV spectrum to which theoretical spectra could be compared, made this an attractive challenge. The molecular structure is shown in Figure .…”

Section: Results: Complex Systemsmentioning

confidence: 99%

“…UV spectrum of dodecaphenyltetracene using all‐electron (black) and pseudopotential (blue) systems, calculated at the DFT‐PBE0 level. The original experimental data is also shown (green), along with an experimental spectrum for tetracene (green) …”

Section: Results: Complex Systemsmentioning

confidence: 99%

Pseudopotential‐fragment spectroscopy for organic molecules and carbon allotropes

Punter

Nava

Carissan

2020

Int J of Quantum Chemistry

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Following on from a previous work (Punter et al., IJQC 2019, 119, 23), pseudopotential sets are developed and tested for a variety of sp 2 and sp 3 carbon fragments. These fragments contain only one or two explicit protons and electrons, and make use of non-atom-centered potentials. They are tested with density functional theory calculations in a selection of chemical environments in which several physical characteristics, including orbital and first ionization energies, are found to be well reproduced.They are then employed in the reproduction of molecular absorption spectra for large organic molecules and carbon allotropes, and are found to recreate both absorption and electronic circular dichroism spectra to a high accuracy. They are also found significantly to increase the computational efficiency of time dependent density functional theory (TDDFT) calculations in which they are used. K E Y W O R D S electronic circular dichroism, electronic structure, hybridized carbon, pseudopotentials, spectroscopy |fflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflffl{zfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflffl} atom-centred potentialswith Y 0, 0 the s spherical harmonic, Y 1, m the p spherical harmonics (across all m), and r 0 J the relative fixed position of the Jth potential with respect to the origin of the pseudoatom to which the potentials are assigned.

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“…An example of perphenylated tetracene was reported at the beginning of 2019 . 1,2,4,5‐Tetrabromo‐3,6‐diphenylbenzene 197b was used as aryne precursor and introduced in two subsequent cycloadditions with tetraphenylfuran 196f and hexaphenylisobenzofuran 67d (Scheme ).…”

Section: Cycloaddition To Carbon–carbon Triple Bondmentioning

confidence: 99%

The Diels–Alder Reaction for the Synthesis of Polycyclic Aromatic Compounds

2019

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The Front Cover shows a variety of dienophiles used in the synthesis of functionalized polycyclic aromatic hydrocarbons over the past decade via the Diels‐Alder reaction. Being discovered almost a century ago, this powerful synthetic method can be used for construction of new materials for organic electronics – one of the modern challenges of organic chemistry. Linear or angular, planar or curved, molecular or polymeric – the product scope is vast and will broaden even more with further development of new diene and dienophile components. More information can be found in the Minireview by P. A. Zaikin et al.

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Dodecaphenyltetracene

Cited by 49 publications

References 14 publications

Flexible C−C Bonds: Reversible Expansion, Contraction, Formation, and Scission of Extremely Elongated Single Bonds

Flexible C−C Bonds: Reversible Expansion, Contraction, Formation, and Scission of Extremely Elongated Single Bonds

Pseudopotential‐fragment spectroscopy for organic molecules and carbon allotropes

The Diels–Alder Reaction for the Synthesis of Polycyclic Aromatic Compounds

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