Facile Preparation of Bright‐Fluorescent Soft Materials from Small Organic Molecules

Abstract

Highly fluorescent and biocompatible soft materials are desirable for many potential applications, but their synthetic processes are somehow complicated. Herein, we have explored the feasibility of synthesis of unconventional fluorescence soft materials from small organic molecules under mild conditions. A new blue-fluorescent soft material with high quantum yield (89.6 %) and eutectic feature prepared by simple heat treatment of citric acid (CA) and cysteine (Cys) aqueous mixtures below 100 °C in air was reported. The as-prepared fluorescent material has the features of facile preparation, low cost, scalable production and easy to process, making it suitable for applications like fluorescent labeling and light-emitting devices. This new finding opens a new venue for the preparation of fluorescent soft materials.

Nontraditional Organic/Polymeric Luminogens with Red‐Shifted Fluorescence Emissions

“…[36] 2) Nitrogen-containing NTLs: amines [poly(amido amine) (PAMAM), [37,38] hyperbranched poly(amino ester) (PAE), [39,40] and poly(amino ether ester)], [41] imines [linear or hyperbranched polyethyleneimine (PEI)], [42][43][44] oximes (hexanal oximes), [11] nitriles [polyacrylonitrile (PAN)], [17] amides [polyacrylamide (PAAm), [45] poly(N-isopropylacrylamide) (PNIPAM), [32] poly(ether amide) (PEA), [46] poly(esteramide-ether) (PEAE), [47] and poly(amido acids)], [48] imides (polysuccinimide), [20,22] polyurethane, [49,50] amino acids, [51,52] and lactams [polyvinylpyrrolidone (PVP), [53] and poly(Nvinylcaprolactam) (PNVCL)]. [54] 3) Sulfur-containing NTLs: thiols (cysteine), sulfones (polysulfone), [55] sulfonic acids [perfluorosulfonate ionomers (PFSI)], [10] sulfonates [poly(4-vinylpyridine)butane-1sulfonate (PVP-S)], [56] and thiourea. [57] 4) NTLs with other atoms.…”

Nonconventional macromolecular luminogens with aggregation‐induced emission characteristics

“…Figure lists some of the most common moieties for the construction of organic fluorophores, like polycyclic aromatic hydrocarbons (PAH), aromatic amines, BODIPY, and fluorescein. With regard to the nonconventional luminogens, so far, more and more examples including molecular and macromolecular, synthetic and natural occurring compounds, such as PAMAM, PEI, starch, cellulose, bovine serum albumin (BSA), PAN, PNHSMA, glucose, poly(acryl acid) (PAA), perfluorosulfonate ionomers (PFSIs), and supramolecular systems are found . For each system, people try to identify the exact contributing moieties.…”

“…Generally, these polymers involve electron‐rich heteroatoms, such as nitrogen (N), oxygen (O), sulfur (S), phosphorus (P), and/or unsaturated C = C and C≡N subgroups. Apart from the most intensively investigated archetypal poly(amidoamine)s (PAMAM), other macromolecular nonconventional luminogens, such as poly(amino ester)s (PAE), poly(ether amide)s (PEA), polyacrylonitrile (PAN), poly( N ‐vinylpyrrolidone) (PVP), polyethylenimines (PEI), polyureas (PU), sulfonated acetone–formaldehyde (SAF) condensates and derivatives, poly( N ‐hydroxysuccinimide methacrylate) (PNHSMA), polysiloxanes, and even supramolecular assemblies have been becoming increasingly eye‐catching owing to their unique intrinsic emissions. Compared with conventional luminophors, they normally enjoy the advantages of good hydrophilicity, facile preparation, environment‐friendliness, outstanding biocompatibility, and so forth, which render them highly suitable for biological and medical applications.…”

Identification of Molecular Fluorophore as a Component of Carbon Dots able to Induce Gelation in a Fluorescent Multivalent-Metal-Ion-Free Alginate Hydrogel

“…These studies followed pioneering work of Yang’s group, who identified the fluorescent citrazinic acid derivative 5-oxo-1,2,3,5-tetrahydroimidazo [1,2-α] pyridine-7-carboxylic acid (denoted as IPCA) as the major luminescent component formed during the hydrothermal synthesis of CDs from CA and ethylenediamine 40 . This and another brightly luminescent molecular fluorophore of a similar structure, namely as 5-oxo-2,3-dihydro-5H-[1,3]-thiazolo[3,2-a]pyridine-3,7-dicarboxylic acid (TPDCA) 41 have been reported as components of fluorescence biodegradable polymers 42,43 , and other kinds of soft composite materials 44–47 .…”