Recent Advances in Functional Polymers Containing Coumarin Chromophores

Abstract

Natural and synthetic coumarin derivatives have gained increased attention in the design of functional polymers and polymer networks due to their unique optical, biological, and photochemical properties. This review provides a comprehensive overview over recent developments in macromolecular architecture and mainly covers examples from the literature published from 2004 to 2020. Along with a discussion on coumarin and its photochemical properties, we focus on polymers containing coumarin as a nonreactive moiety as well as polymer systems exploiting the dimerization and/or reversible nature of the [2πs + 2πs] cycloaddition reaction. Coumarin moieties undergo a reversible [2πs + 2πs] cycloaddition reaction upon irradiation with specific wavelengths in the UV region, which is applied to impart intrinsic healability, shape-memory, and reversible properties into polymers. In addition, coumarin chromophores are able to dimerize under the exposure to direct sunlight, which is a promising route for the synthesis and cross-linking of polymer systems under “green” and environment-friendly conditions. Along with the chemistry and design of coumarin functional polymers, we highlight various future application fields of coumarin containing polymers involving tissue engineering, drug delivery systems, soft robotics, or 4D printing applications.

Recent advances on coumarin-based photoinitiators of polymerization

“…[183] Coumarins are also capable to undergo a reversible [2πs + 2πs] cycloaddition reaction so that their incorporations into polymers could impart intrinsic healability and shape-memory properties to the resulting polymers. [114,184,185] Notably, reversibility of the photochemical dimerization of coumarins in polyesters containing coumarins has been clearly demonstrated. [186] Thus, upon irradiation at 350 nm, dimerization of coumarins could be obtained whereas the symmetric cleavage of the cyclobutane linkage between coumarins could be obtained by irradiating at 254 nm.…”

Development of Photoremovable Linkers as a Novel Strategy to Improve the Pharmacokinetics of Drug Conjugates and Their Potential Application in Antibody–Drug Conjugates for Cancer Therapy

“…The class of coumarin compounds shows various fascinating pharmacological effects, such as antimicrobial, anticoagulant, anti-inflammatory, neuroprotective, anticonvulsant, antidiabetic, anticorrosive, antiproliferative activities, etc. [24][25][26]. In addition, coumarin derivatives are often used in food and cosmetics due to their aromatic odor.…”

“…Along with coumarin and the o-nitrobenzyl group as photo-triggered linkers in drug conjugate applications, there has been new emerging interest in developing different alternatives with improved properties and selectivity in order to meet the challenging demands of the drug development. There appear some novel photolabile protecting groups (Figure 4), such as p-hydrophenacyl (pHP) (25), nitroindoline (NI) (26), benzoin (Bnz) (27), 8,7-bromo-7-hydroxylquinoline (BHQ) (28), and other structural moieties with their photolysis mechanisms and applications comprehensively studied [38]. Among them, the two most promising groups, the thioacetal ortho-nitrobenzaldehyde (TNB) (29) group and photocaged C40-oxidized abasic site (PC4AP) (30), are discussed due to their peculiar activation mechanisms and potential in the applications.…”

Playing construction with the monomer toy box for the synthesis of multi‐stimuli responsive copolymers by reversible deactivation radical polymerization protocols

“…This is the case, for example, of photoacid generators, such as o ‐nitro benzylacrylate, 8,146,164 or N‐hydroxyphathalimide methacrylate, 165 which are photocleaved to yield hydrophilic and pH‐sensitive free acrylate groups. Coumarin moieties are incorporated in the design of functional polymers that can be used in electro‐optical studies, photoreversible systems, chiral stationary phases for HPLC, fluorescent tags and fluoroprobes 166 . Block copolymers containing a PMPMA sequence and a hydrophilic block can self‐assemble in water to form micelles with a PMPMA core.…”