Confined supramolecular polymers in water with exceptional stability, photoluminescence and chiroptical properties

Abstract

Lipid-encased chiral supramolecular polymer nanorods (SPNRs), synthesized by the nanoprecipitation method in water from a hydrophobic naphthalene-diimide derivative, exhibit excellent thermal stability, intense fluorescence and strong CPL.

Frontiers in circularly polarized luminescence: molecular design, self-assembly, nanomaterials, and applications

“…To address this issue, physically mixing chiral component and fluorescent component for constructing CPL-active polymers provides an effective alternative. Using chiral polymers as a template for co-assembly with fluorescent components via noncovalent interactions has proved to be powerful and promising towards CPL emission [131][132][133]. For instance, Lu and co-workers [134] fabricated solid CPL materials through co-assembly of achiral fluorescent molecules and chiral block copolymer (Figure 15a).…”

Core-Substituted Naphthalene-Diimides (cNDI) and Related Derivatives: Versatile Scaffold for Supramolecular Assembly and Functional Materials

“…The compound showed H-bonding-driven self-assembly in methylcyclohexane (MCH)/CHCl 3 (19:1) to produce chiral nanofibers with intense blue-green fluorescence. Introduction of a chiral PDIguest molecule (25) induced enantioselective recognition of the same by the cNDI-based chiral nanofibers with the morphology remaining mostly unaltered. The extent of the chiral recognition was successfully probed by measuring the efficiency of energy transfer from the cNDI donor molecules to the PDI acceptors revealing an enantioselectivity of almost 100%.…”

“…24 In a related report, supramolecular polymerization of this hydrophobic cNDI derivative (26) was studied in a confined aqueous medium (Figure 13). 25 Encapsulation of 26 in the polyethylene glycol (PEG-2000)-based DSPE-lipid (27) allowed the formation of nanorods having lengths in the range of 170-230 nm and widths of $40-60 nm. Dimensions of the lipid-encased cNDI nanorods could be tuned by varying the monomer/lipid ratio.…”

“…Likewise, the CPL studies of the chiral J-aggregates in the confined environment showed a two-fold increase in the g lum values (7.5 Â 10 À2 ) compared to that in decane. 25…”

“…However, energy transfer was observed to take place with higher efficiency in the co-assembled state which could be distinguished from the self-sorted state utilizing spectroscopic and microscopic methods. 20 Nakashima and co-workers have utilized a chiral cNDIbased nanoplatform (23 and 24, Figure 11) for enantioselective recognition of chiral perylenediimide (PDI)-based acceptor molecules (25). 21 To this quest, they synthesised core-diethoxy-substituted bischromophoric cNDI building blocks attached covalently around a central cyclohexanediimide moiety in a chiral fashion (23 and 24).…”