l-Phenylalanine-Tethered, Naphthalene Diimide-Based, Aggregation-Induced, Green-Emitting Organic Nanoparticles

Abstract

The present article delineates the formation of green fluorescent organic nanoparticle through supramolecular aggregation of naphthalene diimide (NDI)-based, carboxybenzyl-protected, l-phenylalanine-appended bola-amphiphile, NDI-1. The amphiphilic molecule is soluble in DMSO, and, with gradual addition of water within the DMSO solution, the amphiphile starts to self-assemble via H-type aggregation to form spherical nanoparticles. These self-assembly of NDI-1 in the presence of a high amount of water exhibited aggregation-induced emission (AIE) through excimer formation. Notably, in the presence of 99% water content, the amphiphile forms spherical aggregated nanoparticles as confirmed from microscopic investigations and dynamic light scattering study. Interestingly, the emission maxima of molecularly dissolved NDI-1 (weak blue fluorescence) red-shifted upon aggregation with increase in water concentration and led to the formation of green-emitting fluorescent organic nanoparticles (FONPs) at 99% water content. These green-emitting FONPs were utilized in cell imaging as well as for efficient transportation of anticancer drug curcumin inside mammalian cells.

Aggregation‐Induced Emission of EuIII Complexes Balanced with Bulky and Amphiphilic Imidazolium Cations in Ethanol/Water Binary Mixtures

“…The same phenomenon was observed for the series of samples with 100 μmol L −1 1 Eu(tta) 4 (Figure S4 in the Supporting Information). The turbidity of the sample is indicative of the aggregate formation of 1 Eu(tta) 4 , as is commonly seen for a given compound in a poor solvent/good solvent combination . From the absorptions in the UV region (Figure d), two bands were detected.…”

“…The turbidity of the sample is indicative of the aggregate formation of 1Eu(tta) 4 ,asi sc ommonly seen for ag iven compound in ap oor solvent/goods olvent combination. [37][38][39] From the absorptions in the UV region ( Figure 1d), two bands were detected. The first one locates around2 75 nm (A1), which is assigned to the absorption of the naphthyl group attached to the imidazolium cation.…”

Salicylic Acid Appended Naphthalene Diimide Organic Linkers: A Systematic Investigation towards Electronic Aspects

“…[12,13] While supramolecular design strategy is concern, self-assemblies of such π-conjugated systems, attachment of amino acid/peptide fragments to organic NDI core is a hastily expanding area of modern research. [14][15][16][17][18][19][20][21][22][23] The high directional nature of hydrogen-bonding from the amino/peptide backbone along with the π-functionality of the aromatic core can be simultaneously utilized to form a supramolecular self-assemblies [24] with promising molecular properties especially electronic behavior. The electroactive/conducting behavior of various organic linkers/building blocks were achieve through the self-assembly features of confined structures/functionalities.…”

“…These properties make NDI an ideal π‐conjugated building block for fabrication of supra molecular architectures too [12,13] . While supramolecular design strategy is concern, self‐assemblies of such π‐conjugated systems, attachment of amino acid/peptide fragments to organic NDI core is a hastily expanding area of modern research [14–23] . The high directional nature of hydrogen‐bonding from the amino/peptide backbone along with the π‐functionality of the aromatic core can be simultaneously utilized to form a supramolecular self‐assemblies [24] with promising molecular properties especially electronic behavior.…”

Solvent‐Induced Self‐Assembly of Naphthalenediimide Conjugated to Tetraphenylethene through D‐ and L‐Alanine

“…These properties render NDI as one of the favourite building blocks to fabricate supramolecular nanostructures via self‐assembly. The diverse supramolecular architectures such as nanotubes, nanospheres, nanofibers, nanobelts, vesicles, golf‐balls, nanocups, catenanes, rotaxanes, flowers, and helical assemblies under various conditions have been reported in literature. These supramolecular structures have potential of applications in organic photovoltaics (OPV), organic field effect transistors (OFETs), dye sensitised solar cells (DSSCs), and light harvesting ,…”