TY  - JOUR
A1  - Schnitzlein, Matthias
A1  - Zhu, Chongwei
A1  - Shoyama, Kazutaka
A1  - Würthner, Frank
T1  - π‐Extended Pleiadienes by [5+2] Annulation of 1‐Boraphenalenes and ortho‐Dihaloarenes
JF  - Chemistry – A European Journal
N2  - Palladium‐catalyzed [5+2] annulation of 1‐boraphenalenes with ortho‐dihaloarenes afforded negatively curved π‐extended pleiadienes. Two benzo[1,2‐i:4,5‐i’]dipleiadienes (BDPs) featuring a seven‐six‐seven‐membered ring arrangement were synthesized and investigated. Their crystal structure revealed a unique packing arrangement and theoretical calculations were employed to shed light onto the dynamic behavior of the BDP moiety and its aromaticity. Further, a naphthalene‐fused pleiadiene was stitched together by oxidative cyclodehydrogenation to yield an additional five‐membered ring. This formal azulene moiety led to distinct changes in optical and redox properties and increased perturbation of the aromatic system.
KW  - annulation
KW  - aromaticity
KW  - azulene
KW  - cyclodehydrogenation
KW  - polycyclic aromatic hydrocarbons
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293919
VL  - 28
IS  - 61
ER  - 
TY  - JOUR
A1  - Schnitzlein, Matthias
A1  - Mützel, Carina
A1  - Shoyama, Kazutaka
A1  - Farrell, Jeffrey M.
A1  - Würthner, Frank
T1  - PAHs Containing both Heptagon and Pentagon: Corannulene Extension by [5+2] Annulation
JF  - European Journal of Organic Chemistry
N2  - Utilizing Pd‐catalyzed [5+2] annulation a series of heptagon‐extended corannulenes could be synthesized from a borinic acid precursor furnished by C−H borylation strategy. Single‐crystal X‐ray analysis revealed the presence of two conformational enantiomers crystallizing in a racemic mixture. Through their embedded five‐ and seven‐membered rings these polycyclic aromatic hydrocarbons (PAHs) exhibit both negative and positive curvature and UV/Vis/NIR absorption spectroscopy as well as cyclic voltammetry experiments provided insights into the influence of larger flanking aromatic systems and electron‐donating substituents encompassing the heptagonal ring. Through [5+2] annulation of acenaphthylene an azulene‐containing PAH with intriguing optoelectronical properties including a very small bandgap and absorption over the whole visible spectrum could be obtained. Theoretical calculations were employed to elucidate the long‐wavelength absorption and aromaticity.
KW  - annulation
KW  - aromaticity
KW  - azulene
KW  - Corannulene
KW  - polycyclic aromatic hydrocarbons
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262627
VL  - 2022
IS  - 5
ER  -