Oxidation of hydroaromatic systems. III. Effect of aromatic stabilization in the dehydrogenation of 1,4-cyclohexadienes

1972 ◽  
Vol 94 (8) ◽  
pp. 2719-2723 ◽  
Author(s):  
Fred Stoos ◽  
Jan Rocek
Keyword(s):  
Aromatic Stabilization

scholarly journals Effective stabilization of a planar phosphorus(iii) center embedded in a porphyrin-based fused aromatic skeleton

2017 ◽  
Vol 8 (12) ◽  
pp. 8231-8239 ◽  
Author(s):  
Keisuke Fujimoto ◽  
Atsuhiro Osuka
Keyword(s):  
Structural Constraint ◽  
Effective Stabilization ◽  
Aromatic Stabilization

Planar phosphorus(iii) centers were effectively stabilized by structural constraint as well as aromatic stabilization in porphyrin-based fused π-conjugated frameworks.

CC/B–N substitution in five membered heterocycles. A computational analysis

2017 ◽  
Vol 41 (9) ◽  
pp. 3619-3633 ◽  
Author(s):  
Vaibhav A. Dixit ◽  
William R. F. Goundry ◽  
Simone Tomasi
Keyword(s):  
Computational Analysis ◽  
Stabilization Energy ◽  
Stabilization Energies ◽  
Neutral Conditions ◽  
Aromatic Stabilization

Novel five-membered azaboroles are aromatic, stable under neutral conditions, isomer stabilization energy is explained using σ-bond and aromatic stabilization energies.

Effects of aromatic stabilization energies of aryl rings of symmetrical diarylethenes

Tetrahedron ◽  
2017 ◽  
Vol 73 (45) ◽  
pp. 6479-6485 ◽  
Author(s):  
Huitao Xu ◽  
Shasha Wei ◽  
Congbin Fan ◽  
Gang Liu ◽  
Shouzhi Pu
Keyword(s):  
Stabilization Energies ◽  
Aromatic Stabilization

scholarly journals Synthesis of a Highly Aromatic and Planar [10]Annulene

2021 ◽  
Author(s):  
Karnjit Parmar ◽  
Christa S. Blaquiere ◽  
Brianna Lukan ◽  
Sydnie Gengler ◽  
Michel Gravel
Keyword(s):  
Stabilization Energy ◽  
Alternative Strategy ◽  
Ring Size ◽  
Ring Strain ◽  
Aromatic Structure ◽  
Close Proximity ◽  
Ring Interaction ◽  
Aromatic Stabilization

As the next neutral structure following Hückels rule, a planar and aromatic [10]annulene is ideal to study the link between ring size and aromaticity. However, the puckered geometry of the parent [10]annulene suggests that the aromatic stabilization energy is not sufficient to overcome the ring strain that exists when the system is forced into planarity. It has been shown computationally that this ring strain can be alleviated through the addition of two or more cyclopropane rings to the periphery, thereby creating theoretically aromatic structures. An alternative strategy to eliminating the issue of ring strain was demonstrated experimentally with the successful preparation of the highly aromatic 1,6-didehydro[10]annulene. However, the system rapidly cyclizes at -40°C to a naphthalene diradical due to the close proximity of the in-plane p-orbitals present in the system. Here we show that cyclopropanating one side of the unstable annulene successfully prevents the destabilizing cross-ring interaction while maintaining a highly aromatic structure. Remarkably, the formed [10]annulene is bench stable and can be stored for extended periods of time.<br>

scholarly journals Kekulene: On-Surface Synthesis, Orbital Structure, and Aromatic Stabilization

2020 ◽  
Author(s):  
Anja Haags ◽  
Alexander Reichmann ◽  
Qitang Fan ◽  
Larissa Egger ◽  
Hans Kirschner ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Density Functional ◽  
Photoemission Spectroscopy ◽  
Scanning Tunneling ◽  
Orbital Structure ◽  
Tunneling Microscopy ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Highest Occupied Molecular Orbital ◽  
Shed Light ◽  
Aromatic Stabilization

We revisit the question of kekulene’s aromaticity by focusing on the electronic structure of its frontier orbitals as determined by angle-resolved photoemission spectroscopy. To this end, we have developed a specially designed precursor, 1,4,7(2,7)-triphenanthrenacyclononaphane-2,5,8-triene, which allows us to prepare sufficient quantities of kekulene of high purity directly on a Cu(111) surface, as confirmed by scanning tunneling microscopy. Supported by density functional calculations, we determine the orbital structure of kekulene’s highest occupied molecular orbital by photoelectron tomography. In agreement with a recent aromaticity assessment of kekulene based solely on C–C bond lengths, we conclude that the π-conjugation of kekulene is better described by the Clar model rather than a superaromatic model. Thus, by exploiting the capabilities of photoemission tomography, we shed light on the question which consequences aromaticity holds for the frontier electronic structure of a π-conjugated molecule.<br>

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