Double π‐Extended Undecabenzo[7]helicene

Abstract

This work reports the first double p-extended undecabenzo[7]helicene 1,w hich is al arge chiral nanographene,composed of 65 fused rings and 186 conjugated carbon atoms.T he molecular identity of 1 has been confirmed by single crystal X-rayd iffraction. Aw ine coloured solution of 1 in dichloromethane absorbs light from ultraviolet to the near infrared, featuring an extremely large molar absorption coefficient of 844 000 M À1 cm À1 at 573 nm. Optically pure 1 shows ar ecordh igh electronic circular dichroism intensity in the visible spectral range (j De j= 1375 M À1 cm À1 at 430 nm) knownf or any discrete polycyclic aromatic hydrocarbon. These unusual photophysical properties of 1 contrast sharply with those of amono-undecabenzo[7]helicene derivative 2.

Double π‐Extended Undecabenzo[7]helicene

“…800 nm) of the absorption spectrum, is 1.55 eV,w hich is 0.36 eV Figure 3. A) X-ray crystal structure of 1, [26] with the ORTEP drawing set as 50 %p robability.B )OverlappedX-ray structures of the embedded UB7H and [7]helicene. C) Packing of 1 in the solid state with (M,M)-1 in purple and (P,P)-1 in gray.…”

Tuning the (Chir)Optical Properties and Squeezing out the Inherent Chirality in Polyphenylene‐Locked Helical Carbon Nanorings

“…Notably, CPL reflects structural information of chiral aromatic systems from excited states and has many promising applications in CPL lasers, optical data and optical quantum information storage, optical spintronics, 3D optical displays, asymmetric photosynthesis, molecular switches, biochemical sensors, and bio‐responsive imaging [9] . In accordance with such broad interest, different new types of topologically non‐planar nanocarbons such as alkyl‐linked curved acenes, [8c] helicarenes, [8f,10] curved saddle nanographenes, [8b,11] helical graphene nanoribbons, [8g,12] aromatic belts, [13] and macrocyclic arenes, [14] have been constructed to explore novel optical activity. However, reports of carbon nanorings with chiroptical properties, particularly CPL activity, are still scarce [15] .…”

Synthesis of Giant Dendritic Polyphenylenes with 366 and 546 Carbon Atoms and Their High‐vacuum Electrospray Deposition

“…[19] Notably, solution-based synthesis of large NGs with up to 258 sp 2 carbons has been recently reported, [31] albeit non-planarity is implanted into the molecular structure. [32][33][34] This can be an alternative approach to overcome the size limit of the current NG synthesis, while the synthesis of giant planar NGs remains a distinct challenge.…”