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.

An efficient process for the Cu(0)-mediated synthesis and subsequent chain extension of poly(methyl acrylate) macroinitiator

A process combining a continuous tubular and a semi-batch reactor is established as an efficient method for the synthesis of block copolymers.

Lipidated polymers for the stabilization of cubosomes: nanostructured drug delivery vehicles

Lipidated polymers, like their protein counterparts, may be useful in fields as diverse as biochemistry and drug delivery. As such, strategies for preparing lipidated polymers with defined molecular architecture are clearly warranted. Herein, we describe a broadly-applicable methodology for synthesizing such lipidated materials, and demonstrate how they can be applied to the preparation of nanostructured drug delivery vehicles.

Recent Developments in the Synthesis of Biomacromolecules and their Conjugates by Single Electron Transfer-Living Radical Polymerization

Single electron transfer-living radical polymerization (SET-LRP) represents a robust and versatile tool for the synthesis of vinyl polymers with well-defined topology and chain end functionality. The crucial step in SET-LRP is the disproportionation of the Cu(I)X generated by activation with Cu(0) wire, powder, or nascent Cu(0) generated in situ into nascent, extremely reactive Cu(0) atoms and nanoparticles and Cu(II)X₂. Nascent Cu(0) activates the initiator and dormant chains via a homogeneous or heterogeneous outer-sphere single-electron transfer mechanism (SET-LRP). SET-LRP provides an ultrafast polymerization of a plethora of monomers (e.g., (meth)-acrylates, (meth)-acrylamides, styrene, and vinyl chloride) including hydrophobic and water insoluble to hydrophilic and water soluble. Some advantageous features of SET-LRP are (i) the use of Cu(0) wire or powder as readily available catalysts under mild reaction conditions, (ii) their excellent control over molecular weight evolution and distribution as well as polymer chain ends, (iii) their high functional group tolerance allowing the polymerization of commercial-grade monomers, and (iv) the limited purification required for the resulting polymers. In this Perspective, we highlight the recent advancements of SET-LRP in the synthesis of biomacromolecules and of their conjugates.

Double-bond-containing polyallene-based triblock copolymers via phenoxyallene and (meth)acrylate

A series of ABA triblock copolymers, consisting of double-bond-containing poly(phenoxyallene) (PPOA), poly(methyl methacrylate) (PMMA), or poly(butyl acrylate) (PBA) segments, were synthesized by sequential free radical polymerization and atom transfer radical polymerization (ATRP). A new bifunctional initiator bearing azo and halogen-containing ATRP initiating groups was first prepared followed by initiating conventional free radical homopolymerization of phenoxyallene with cumulated double bond to give a PPOA-based macroinitiator with ATRP initiating groups at both ends. Next, PMMA-b-PPOA-b-PMMA and PBA-b-PPOA-b-PBA triblock copolymers were synthesized by ATRP of methyl methacrylate and n-butyl acrylate initiated by the PPOA-based macroinitiator through the site transformation strategy. These double-bond-containing triblock copolymers are stable under UV irradiation and free radical circumstances.

PDMAEMA-b-PPOA-b-PDMAEMA double-bond-containing amphiphilic triblock copolymer: synthesis, characterization, and pH-responsive self-assembly

This article reports a new pH-responsive double-bond-containing ABA triblock copolymer synthesized via a combination of free radical polymerization and SET-LRP.

ATRP synthesis of polyallene-based amphiphilic triblock copolymer

This article reports the synthesis of a new amphiphilic double-bond-containing ABA triblock copolymer by a combination of free radical polymerization and ATRP.

Polyallene-based amphiphilic triblock copolymer via successive free radical polymerization and ATRP

This article reports the synthesis of amphiphilic double-bond-containing ABA triblock copolymer by a combination of free radical polymerization and ATRP.

Cu(0)-mediated living radical polymerization: recent highlights and applications; a perspective

Cu(0)-mediated living radical polymerization or single electron transfer living radical polymerization (Cu(0)-mediated LRP or SET-LRP) is a versatile polymerization technique that has attracted considerable interest during the past few years for the facile preparation of advanced materials.

A rational approach to activated polyacrylates and polymethacrylates by using a combination of model reactions and SET-LRP of hexafluoroisopropyl acrylate and methacrylate

A new class of activated polyacrylates was elaborated by a combination of model reactions and SET-LRP of hexafluoroisopropyl acrylate and methacrylate.

Self-activation and activation of Cu(0) wire for SET-LRP mediated by fluorinated alcohols

Herein we report the self-activation and activation of Cu(0) wire used to form a catalyst in single-electron transfer living radical polymerization (SET-LRP) in two fluorinated alcohols employed as solvents, 2,2,2-trifluoroethanol (TFE) and 2,2,3,3-tetrafluoropropanol (TFP).

Synthesis of high molar mass poly(n-butyl acrylate) and poly(2-ethylhexyl acrylate) by SET-LRP in mixtures of fluorinated alcohols with DMSO

SET-LRP of n-butyl acrylate (nBA) and 2-ethylhexyl acrylate (EHA) initiated with bis(2-bromopropionyl)ethane (BPE) to synthesize high molar mass poly(nBA) and poly(EHA) was carried out in binary mixtures of 2,2,2-trifluoroethanol (TFE) or 2,2,3,3-tetrafluoropropanol (TFP) with DMSO at 50 °C.

SET-LRP of semifluorinated acrylates and methacrylates

For the first time SET-LRP of 1H,1H,2H,2H-perfluorooctyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, 1H,1H,5H-octafluoropentyl acrylate and 1H,1H,5H-octafluoropentyl methacrylate in 2,2,2-trifluoroethanol as the solvent at 25 °C for acrylates and at 50 °C for methacrylate was accomplished.

Reversible deactivation radical polymerization in the presence of zero-valent metals: from components to precise polymerization

We highlight recent work from the advent of zero-valent metal-mediated RDRP looking at advances in its components and the synthesis of well-defined polymers.

Thermo-responsiveness of polysiloxanes grafted with poly(dimethyl acrylamide) segments

Thermo-sensitive polymers are of outstanding importance due to their ability to undergo controlled major changes in their properties as a response to minor modifications in temperature. The syntheses of novel polymers by grafting polysiloxane containing chlorobenzyl groups in the side chain by the homopolymerization of N,N′-dimethyl acrylamide (DMA) or the copolymerization of DMA and methyl methacrylate (MMA) using SET-LRP technique are presented. The polymers were characterized by 1H-NMR, UV, and fluorescence spectroscopy, and DSC. The thermo-sensitivity and the lower critical solution temperature (LCST), as well as the aggregation phenomena during the phase transition are evidenced by dynamic light scattering (DLS) and rheology.