Positional Effect of π-extension in Triple Helicenes

The targeted application of multiple helicenes in photo-optical applications requires their rational design. Toward this goal, we report on the synthesis of pyrene-based triple helicene 1 and investigate the positional effect of extension of the π-conjugated system on the photo-chemical and chiro-optical properties of triple helicenes. The conformational and aggregatory behavior of 1 were studied both experimentally using VT NMR spectroscopy and computationally using high-level DFT computations. Although π-extension was observed to have a marked effect on the spectroscopic properties of triple helicenes, comparison with other known π-extended helicenes reveals that the position at which π-extension is introduced is only of nominal importance. Our results thus suggest that the presence of a particular helicene motif is dominant in dictating the physico-chemical properties of triple helicenes.

Positional Effect of π-extension in Triple Helicenes

Application of multiple helicenes in photo‐optical applications requires their rational design. We therefore here report on the synthesis of pyrene‐based triple helicene 1, to study the positional effect of extension of the π‐conjugated system on the photo‐chemical and chiro‐optical properties of triple helicenes. The conformational and aggregatory behavior of 1 were studied both experimentally using VT NMR spectroscopy and computationally using high‐level DFT computations. Although π‐extension was observed to have a marked effect on the spectroscopy properties of triple helicenes, comparison with other known π‐extended helicenes reveals that the position at which π‐extension is introduced is only of nominal importance. Our results thus suggest that the presence of a particular helicene motive is dominant in dictating the physico‐chemical properties of triple helicenes.

Through Structural Isomerism: Positional Effect of Alkyne Functionality on Molecular Optical Properties

The study on the effect of alkyne functionality in manipulating the optical properties of donor-π-acceptor-type molecular scaffolds has been scarce in literature compared to alkene functional group. Here, two structurally...

Chiral recognition coupled with chemometrics using boronate ensembles containing D-π-A cyanostilbenes

Two types of boronic acid-appended D-π-A cyanostilbenes were synthesized to produce chiral boronate ensembles via dehydration with tartaric acid. The aggregation-induced high sensitivity and positional effect of the CN group...

Non-doped OLEDs based on tetraphenylethylene phenanthroimidazoles with negligible efficiency roll-off: Effect of end groups regulated stimuli responsive AIE luminogens

The positional isomers of phenanthroimidazoles, TPE-NPPB and TPE-APPB have been designed to understand the positional effect of triphenylamine (TPA) and tetraphenylethylene (TPE) units on aggregation induced emission and mechanochromism. Phenanthroimidazoles,...