Assembling Complex Macromolecules and Self-Organizations of Biological Relevance with Cu(I)-Catalyzed Azide-Alkyne, Thio-Bromo, and TERMINI Double "Click" Reactions

In 2022, the Nobel Prize in Chemistry was awarded to Bertozzi, Meldal, and Sharpless "for the development of click chemistry and biorthogonal chemistry". Since 2001, when the concept of click chemistry was advanced by Sharpless laboratory, synthetic chemists started to envision click reactions as the preferred choice of synthetic methodology employed to create new functions. This brief perspective will summarize research performed in our laboratories with the classic Cu(I)-catalyzed azide-alkyne click (CuAAC) reaction elaborated by Meldal and Sharpless, with the thio-bromo click (TBC) and with the less-used, irreversible TERminator Multifunctional INItiator (TERMINI) dual click (TBC) reactions, the last two elaborated in our laboratory. These click reactions will be used to assemble, by accelerated modular-orthogonal methodologies, complex macromolecules and self-organizations of biological relevance. Self-assembling amphiphilic Janus dendrimers and Janus glycodendrimers together with their biological membrane mimics known as dendrimersomes and glycodendrimersomes as well as simple methodologies to assemble macromolecules with perfect and complex architecture such as dendrimers from commercial monomers and building blocks will be discussed. This perspective is dedicated to the 75th anniversary of Professor Bogdan C. Simionescu, the son of my (VP) Ph.D. mentor, Professor Cristofor I. Simionescu, who as his father, took both science and science administration in his hands, and dedicated his life to handling them in a tandem way, to their best.

Biocatalytic nanoparticles for the stabilization of degassed single electron transfer-living radical pickering emulsion polymerizations

Synthetic polymers are indispensable in many different applications, but there is a growing need for green processes and natural surfactants for emulsion polymerization. The use of solid particles to stabilize Pickering emulsions is a particularly attractive avenue, but oxygen sensitivity has remained a formidable challenge in controlled polymerization reactions. Here we show that lignin nanoparticles (LNPs) coated with chitosan and glucose oxidase (GOx) enable efficient stabilization of Pickering emulsion and in situ enzymatic degassing of single electron transfer-living radical polymerization (SET-LRP) without extraneous hydrogen peroxide scavengers. The resulting latex dispersions can be purified by aqueous extraction or used to obtain polymer nanocomposites containing uniformly dispersed LNPs. The polymers exhibit high chain-end fidelity that allows for production of a series of well-defined block copolymers as a viable route to more complex architectures.

SET-LRP of Bio- and Petroleum-Sourced Methacrylates in Aqueous Alcoholic Mixtures

Single-electron transfer-living radical polymerization (SET-LRP) in "programmed" aqueous organic biphasic systems eliminates the judicious choice of solvent and also provides accelerated reaction rates. Herein, we report efforts to expand the monomer scope for these systems by targeting methacrylic monomers and polymers. Various environmentally friendly aqueous alcoholic mixtures were used in combination with Cu(0) wire catalyst, tris(2-dimethylaminoethyl)amine (Me₆-TREN) ligand, and p-toluenesulfonyl chloride (Ts-Cl) initiator to deliver well-defined polymethacrylates from methyl methacrylate, butyl methacrylate, and other monomers derived from biomass feedstock (e.g., lactic acid, isosorbide, furfural, and lauric acid). The effect of water on the nature of the reaction mixture during the SET-LRP process, reaction rate, and control of the polymerization is discussed. The control retained under the reported conditions is demonstrated by synthesizing polymers of different targeted molar mass as well as quasi-block AB copolymers by "in situ" chain extension at high conversion. These results highlight the capabilities of SET-LRP to provide sustainable solutions based on renewable resources.

Expanding the monomer scope of linear and branched vinyl polymerisations via copper-catalysed reversible-deactivation radical polymerisation of hydrophobic methacrylates using anhydrous alcohol solvents

The use of anhydrous alcohols for Cu-catalysed reversible-deactivation radical polymerisation of a wide range of hydrophobic methacrylates has been explored in detail.

Highly reactive α-bromoacrylate monomers and Michael acceptors obtained by Cu(ii)Br2-dibromination of acrylates and instantaneous E2 by a ligand

The importance of the order of addition of reagents in SET-LRP.

Macromonomers, telechelics and more complex architectures of PMA by a combination of biphasic SET-LRP and biphasic esterification

Macromonomers and telechelics of PMA via biphasic SET-LRP and biphasic esterification with potassium acrylate.

Acetone: a solvent or a reagent depending on the addition order in SET-LRP

The importance of reagent order in biphasic SET-LRP in acetone/water mixtures is shown.

Addressing the role of triphenylphosphine in copper catalyzed ATRP

A new Atom Transfer Radical Polymerization (ATRP) process with triphenylphosphine (PPh₃) and [Cu^IIMe₆TREN]²⁺ as the catalyst system is reported.

MALDI-LID-ToF/ToF analysis of statistical and diblock polyacrylate copolymers

We report the use of MALDI-LID-ToF/ToF utilising the laser induced dissociation (LID) fragmentation technique, which has been almost exclusively applied to protein/peptide analysis to date.

Cu(0)-RDRP of styrene: balancing initiator efficiency and dispersity

The optimisation of all components within Cu(0)-wire mediated polymerisation of styrene is illustrated yielding well-defined polystyrene with enhanced initiator efficiency and dispersity at higher molecular weights.

Acrylate-macromonomers and telechelics of PBA by merging biphasic SET-LRP of BA, chain extension with MA and biphasic esterification

Chain extension of PBA with MA allows the preparation of acrylate-functional PBA.

Cu(0)-RDRP of acrylates based on p-type organic semiconductors

A series of four acrylic monomers were synthesized based on p-type organic semiconductor motifs found commonly in organic light-emitting diodes (OLEDs), organic thin-film transistors (OTFTs) and organic photovoltaics (OPVs).

SET-LRP in biphasic mixtures of fluorinated alcohols with water

Efficient and inexpensive SET-LRP in biphasic-mixtures of fluorinated alcohols with water.