Locally Rotated Chiral Molecular Tiara with Reversible CPL Emissions

Abstract

Chiroptical materials capable of emitting circularly polarized luminescence (CPL) have been gaining intensive interest for their wide applications in fields of materials. In this work, a locally rotated molecular tiara Py5P5, in which five bulky pyrene units locate at one rim of Py5P5, and five small methoxy groups at the other, is designed. The planar chiral skeleton of Py5P5 can make five pyrene units being ordered in asymmetrical manner to arise the CPL emission from pyrene excimer, and the small methoxy groups rim in the other can ensure the interconversion between pR‐ and pS‐conformers of Py5P5 freely via local rotation. Thus, both left‐handed and right‐handed CPL may emit from pyrene units of Py5P5 stacked in the asymmetrical order with a high |glum| up to 1.28 × 10−3 under the induction of chiral amino acid derivatives. It is the first observation that both right‐handed and left‐handed CPL from pyrene excimer can be arisen from a single molecule by adding the simple chiral guests.

Functionalization of pillar[n]arenes towards optically responsive systems via host–guest interactions

“…8). 137 A rimdifferentiated pillar [5]arene H27, in which all five pyrene units were located on one rim and all five methoxy groups were located on the other rim, was prepared. The methoxy groups were small enough to pass into the cavity of the pillar [5]arene and caused exchange between the pS and pR forms by inducing local rotation within 1801.…”

Circularly polarized luminescence from a common alkoxy pillar[5]arene and its co‐aggregates with π‐conjugated rods

“…The CPL signal at around 500 nm was also enhanced by the increasing P5OCH 2 Cy/6 F ratio, similar to the CD peak at around 350 nm, but the maximum intensity was observed at a ratio of 2.0/1.0 due to additional long-range influence by weakly associated P5OCH 2 Cy molecules among other factors (Figures 7 and S4-4). Importantly, the observed g lum value of 2.9 × 10 −2 at 472 nm is much higher than those of pillar[n]arene derivatives which can be used in solution, [30,31,[33][34][35][36][37][38] and even superior to any system exploiting the pillar[n]arene planar chirality, including cast film materials. [32,39,40] The B CPL value [47] was calculated as a hypothetical 1:2 complexed species with ε = 7.5 × 10 4 M −1 cm −1 (λ abs = 312 nm) to be ca.…”

“…Apart from these molecules with the trade-offs, hybrid systems with other photo-responsive units enabled easy alteration of their basic optical properties. They attained comparable or higher dissymmetry as single molecules [36][37][38] (4) and supramolecular aggregates [39,40] (5) due to the effective transfer of the planar chirality. This research prompted us to combine a simple alkoxy pillar [5]arene with a π-conjugated guest in expectation of a chiroptical response based on the highest occupied molecular orbital (HOMO) of the former and the lowest unoccupied molecular orbital (LUMO) of the latter.…”

The Mn2+‐Doped Chiral 2D Perovskite with Strong Orange Fluorescent and Enhanced Circularly Polarized Luminescence

“…Chiral light may endow achiral matter with chiral property or structure, while chiral nanomaterials can transform achiral light into chiral light. [6] Chiral nanomaterials with CPL activity have broad application prospects in many fields, such as 3D display, [7,8] photoelectric devices, [9][10][11] biological probes, [12,13] catalysis, [14,15] and anticounterfeiting [16] and have attracted much attention.…”