Highly Efficient Amide Michael Addition and Its Use in the Preparation of Tunable Multicolor Photoluminescent Polymers

Abstract

The amide bond is one of the most pivotal functional groups in chemistry and biology. It is also the key component of proteins and widely present in synthetic materials. The majority of studies have focused on the formation of the amide group, but its postmodification has scarcely been investigated. Herein, we successfully develop the Michael additions of amide to acrylate, acrylamide, or propiolate in the presence of phosphazene base at room temperature. This amide Michael addition is much more efficient when the secondary amide instead of the primary amide is used under the same conditions. This reaction was applied to postfunctionalize poly(methyl acrylate-co-acrylamide), P(MA-co-Am), and it is shown that the amide groups of P(MA-co-Am) could be completely modified by N,N-dimethylacrylamide (DMA). Interestingly, the resulting copolymer exhibited tailorable fluorescence with emission wavelength ranging from 380 to 613 nm, which is a desired property for luminescent materials. Moreover, the emissions of the copolymer increased with increasing concentration in solution for all excitation wavelengths from 320 to 580 nm. Therefore, this work not only develops an efficient t-BuP 4 -catalyzed amide Michael addition but also offers a facile method for tunable multicolor photoluminescent polymers, which is expected to find a wide range of applications in many fields, such as in anticounterfeiting technology.

Through-Space Interactions in Clusteroluminescence

“…Actually, it is another general feature for CLgens. Figure a,b exhibits the fluorescence microscope images of two CLgens, sodium alginate and P­(MA- co -DMAA). , With the increase of excitation wavelength from UV to green, the fluorescence colors change from blue to red. In the meantime, the brightness of the CL was enhanced when the concentration of CLgens increased, and the film was brighter than the solution (Figure b).…”

“…(c) PL spectra of a DMSO solution of P­(MA- co -DMAA) ( c = 10 mg/mL) excited at 320–580 nm. Adapted from ref . Copyright 2020 American Chemical Society.…”

High-Efficiency Long-Wavelength Fluorescent Hyperbranched Polysiloxanes: Synthesis, Emission Mechanism, Information Encryption, and Film Preparation

“…Interestingly, unconventional fluorescent polymers usually exhibit excitation-dependent emission, their emission wavelength gradually redshifts with increasing the excitation wavelength. , Therefore, these polymers have the potential to emit long-wavelength emissions. For example, Yang et al functionalized poly­(methyl acrylate- co -acrylamide) with N , N -dimethylacrylamide via an efficient amide Michael addition . The emission of such a polymer exhibits tailorable fluorescence with an emission wavelength ranging from 380 to 613 nm.…”

Synthesis of thermoresponsive nonconjugated fluorescent branched poly(ether amide)s via oxa-Michael addition polymerization

“…Michael addition polymerization is a versatile technique that has been widely used for the preparation of nonconjugated fluorescent polymers. [50][51][52][53] Particularly in biological applications, oxa-Michael addition polymerization has significant advantages over other methods because stable, odorless, and nontoxic hydroxyl monomers are used. Although the oxa-Michael addition polymerization of hydroxyl monomers with unsaturated carbon-carbon double or triple bond monomers has been reported, [54][55][56][57][58] reports on the preparation of thermoresponsive nonconjugated fluorescent polymers using this approach are relatively scarce.…”