The interactions between auxochromic groups in π-conjugated functional molecules dictate their electronic properties. From the standpoint of potential applications, understanding and control of such interactions is a vital requirement for the material design. In this communication, we describe the design, synthesis, and functional properties of a novel class of helically chiral diimide molecules, namely, [n]HDI-OMe (n = 5, 6, and 7), in which two imide units are connected via an [n]helicene skeleton. The experimental results supported by quantum chemical calculations reveal that the helical backbone in these molecules offers not only through-bond but also through-space conjugation between imide groups, which leads to distinct optical and electrochemical properties when compared to the related [n]helicenes and rylene diimides.

Herein, we have synthesized an enantiomerically pure propeller-shaped PAH, C 90 H 48 ,p ossessing three [7]helicene and three [5]helicene subunits. This compound can be obtained in gram quantities in as traightforward manner. Thep hotophysical and chiroptical properties were investigated using UV/Vis absorption and emission, opticalr otation and circular dichroism spectroscopy,s upported by DFT calculations. The nonlinear opticalp roperties were investigated by two-photon absorption measurements using linearlya nd circularly polarized light.T he extremely twisted structure and packing of the homochiral compound werei nvestigated by single-crystal X-ray diffraction analysis.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.org/10.Figure 5. Experimental (blue line, c = 1.4 10 À5 m)and calculated (black vertical lines and gray line, TD-DFT/B3LYP/6-31G(d,p)) ECD spectrumo f (M,M,M,P,P,P)-3 in chloroform.Figure 6. One-photon (blue lines) and two-photon (red lines) absorption spectra of( M,M,M,P,P,P)-3 in THF (solid line) and toluene(dottedl ine).

Highly twisted large PAHs offer, in addition to physical properties, a feature of chirality, which results in non-super imposable mirror-image structures of these compounds that can be resolved into optically active enantiomers. This process, however, is cumbersome, which largely restricts the available quantity of materials in optically active form and represents a great hurdle for their applications. Herein, we have synthesized an enantiomerically pure propeller-shaped PAH, C₉₀H₄₈, possessing three [7]helicene and three [5]helicene subunits. This compound can be obtained in gram quantities in a straight-forward manner. The photophysical and chiroptical properties were investigated using UV−vis absorption and emission, optical rotation and circular dichroism spectroscopy, supported by DFT calculations. The non-linear optical properties were investigated by two-photon absorption measurements using linearly and circularly polarized light. The extremely twisted structure and packing of the homochiral compound were investigated by single crystal X-ray diffraction analysis

Attachment of cyclic imide groups to polycyclic aromatic hydrocarbons (PAHs) leads to fascinating electronic and luminescence properties, the rylene diimides being the representative example. The close to unity fluorescence quantum yields and electron acceptor properties render them suitable for application in organic electronics and photovoltaics. The recent reports show that in line with planar PAHs, the imide functionalization has also endowed helical three-dimensional PAHs with similar beneficial photophysical properties. In this article, we have summarized the state-of-the-art research developments in the field of helicene-imide hybrid functional molecules, with a particular focus on synthesis, (chir)optical and redox properties, and applications in electronics. Additionally, we have highlighted our recent work, introducing a novel family of functional chiral molecules, namely, [n]helicene diimides the three-dimensional relatives of rylene diimides.

Highly twisted large PAHs offer, in addition to physical properties, a feature of chirality, which results in non-super imposable mirror-image structures of these compounds that can be resolved into optically active enantiomers. This process, however, is cumbersome, which largely restricts the available quantity of materials in optically active form and represents a great hurdle for their applications. Herein, we have synthesized an enantiomerically pure propeller-shaped PAH, C₉₀H₄₈, possessing three [7]helicene and three [5]helicene subunits. This compound can be obtained in gram quantities in a straight-forward manner. The photophysical and chiroptical properties were investigated using UV−vis absorption and emission, optical rotation and circular dichroism spectroscopy, supported by DFT calculations. The non-linear optical properties were investigated by two-photon absorption measurements using linearly and circularly polarized light. The extremely twisted structure and packing of the homochiral compound were investigated by single crystal X-ray diffraction analysis