“First Come, First Served” and Threshold Effects in a Central‐to‐Planar‐to‐Helical Hierarchical Chiral Induction

Abstract

Perylene diimide tethered pillar [5]arene derivatives form aggregates in non-polar organic solvents, and the complexation of cationic amino acid ethyl ester (cAA-OEt) with the aggregates induce a central-toplanar-to-helical chirality transfer, leading to intensive circular dichroism (CD) signals having dissymmetric factors (g abs ) of up to 3.67 × 10 À 2 . The hierarchical chiral induction exhibited an intriguing threshold dose effect, namely, the chiral induction does not occur in the low concentration range of cAA-OEt but is triggered when cAA-OEt exceeds a threshold concentration. The inhibited interconversion between the Rp and Sp conformers of pillar[5]arene, which is further restricted in the aggregation, plays a crucial role in the threshold effect. When adding enantiopure cAA-OEt first to the threshold concentration and then adding an equal amount of the antipodal cAA-OEt to give cAA-OEt in racemic form, CD spectra having the same sign as the CD induced by first adding pure cAA-OEt were induced, thus showing an unprecedented "first come, first served" effect.

Hierarchical chirality transfer of perylene diimide-tethered pillar[5]arenes for configuration and type differentiation of amino acid derivatives

“…26 Our recent research has shown that chiral induction with perylene diimide (PDI)-tethered P[5]s displayed a central-to-planar-to-helical hierarchical chirality transfer with unique chiral induction thermal dynamic behavior. 4,27–29 Notably, we observed dual chiroptical inductions, yielding distinct CD signals at both P[5] and PDI transitions, respectively. It occurred to us that the unique CD signals at different transitions could be harnessed to create a multidimensional signal combination, which has the potential not only to distinguish between different configurations but also to differentiate chiral homologs using just a single chiroptical sensor.…”

“…S3, ESI†). 4,30,31 To Agg-S1 in 95% MCH (containing 5 vol% CHCl 3 ), adding cAA-OEt induced CD signals at the P[5] absorption band and intensive ECCD at the S 0 –S 1 transition (400–570 nm) of PDI moiety (Fig. 2a and Fig.…”

“…Supramolecular chirality has been attracting wide attention and has given rise to many intriguing research topics, such as chirality induction, transfer, sensing, memory and amplification. 1–8 Supramolecular chirality sensing is promising for detecting absolute configuration and optical purity based on spectroscopic methods, including UV/Vis spectra, fluorescence, NMR and circular dichroism (CD) spectroscopies. 9–13 Compared to conventional chromatographic techniques, supramolecular chirality sensing offers the benefit of rapid and inexpensive high-throughput screening.…”

Chiroptical regulation of macrocyclic arenes with flipping-induced inversion of planar chirality

“…16a). 60 Perylene diimide (PDI)-bridged 22 was found to complex with amino acid derivatives, resulting in a helical stacking of PDI, and the CD spectra gradually increase with the concentration of the amino acids. On the contrary, the addition of the amino acids to the solution containing 23b – 23e did not immediately induce a CD signal.…”

Recent advances of triplet–triplet annihilation upconversion in solvent-free solid materials

“…Our studies have shown that the supramolecular self-assembly of the UC components significantly improved the TTA-UC efficiencies in the solution [64][65][66][67] and also demonstrated that well-organized photosubstrates by supramolecular interactions showed unique photochemical and photophysical properties. [68][69][70][71][72][73][74][75][76][77][78][79][80][81] In 2022, we 52 prepared an organic-inorganic nanocomposite by the self-assembly of poly(N-vinyl-2-pyrrolidone) (PVP) and LAPONITE s XLG clay and was used as an excellent solid matrix for TTA-UC. The UC hydrogel gel was prepared as follows: the LAPONITE s colloids with 4 wt% in deionized water were added N-vinyl-2-pyrrolidone (NVP) and azodiisobutyronitrile (AIBN) to give a homogeneous solution (step 1 and step 2), to which a highly concentrated DMSO solution of sensitizers and acceptors was added to form the precursor solution (step 3 and step 4); a small amount of surfactant Triton X-100 was added for the better dispersion of the sensitizers in water (step 5).…”