Anionic Synthesis of Mono- and Heterotelechelic Polystyrenes via Thiol–Ene “Click” Chemistry and Hydrosilylation

The Use of the Thiol-Ene Addition Click Reaction in the Chemistry of Organosilicon Compounds: An Alternative or a Supplement to the Classical Hydrosilylation?

This review presents the main achievements in the use of the thiol-ene reaction in the chemistry of silicones. Works are considered, starting from monomers and ending with materials.The main advantages and disadvantages of this reaction are demonstrated using various examples. A critical analysis of the use of this reaction is made in comparison with the hydrosilylation reaction.

Aryl radical initiators accumulated within layered silicates realize polystyrene with directly and regioselectively bonded aryl-terminal groups

The arbitrary design of a terminal group of polymers exploits the still-veiled functions of polymers with potential for application in fields such as drug delivery systems, photonics, and energy conversions. Here we demonstrate for the first time that polystyrenes with directly and regioselectively bonded aryl-terminal groups can be obtained via styrene radical polymerization initialized by arbitrary aryl radicals accumulated within the interlayer space of smectite clay minerals, which can be prepared by our developed 'Clay Catalysed ab intra Deamination (CCD)' method.

A thiol–ene click reaction with preservation of the Si–H bond: a new approach for the synthesis of functional organosilicon compounds

This work presents an approach for the preparation of functional hydrosilanes.

Thiol–ene coupling reaction achievement and monitoring by “in situ” UV irradiation NMR spectroscopy

In this study, the possibilities of a new “in situ” LED UV illumination NMR spectroscopic technique for performing an initiator-free thiol–ene “click” coupling reaction of an allyl-functionalized poly(allyl glycidyl ether) (PAGE) prepolymer with a number of mono- and di-oligo polyethylene glycol (PEG) thiols is demonstrated. The state-of-the-art setup constructed with LEDs as UV light sources that illuminate through optical fibers directly into an NMR testing tube at a fixed wavelength of 365 nm is appropriate for various polymeric materials and biologically active substances. The selected experimental protocol uses a series of periods of irradiation and dark periods, thus providing opportunities to conduct an effective thiol–ene “click” reaction and simultaneously study the kinetics of the photochemical reaction with the exposure time, as well as macromolecular association directly in a solution applying the whole types of NMR methods: from conventional ¹H or ¹³C NMR to diffusion NMR spectroscopy (DOSY). In addition, the molecular mass characteristics of the prepared copolymers were studied by gel-permeation chromatography (GPC). The observed differences in the reaction rates as well as in the size of species formed (the corresponding hydrodynamic radiuses R_h of aggregates) as a result of the coupling process of parent PAGE prepolymers and model PEG thiols were thoroughly discussed and the reaction pathway proposed.

An “In situ” LED UV illumination NMR setup for achievement of initiator-free coupling reactions of allyl-functionalized poly(allyl glycidyl ether) with polyethylene glycols thiols.

Recent advances in organic–inorganic well-defined hybrid polymers using controlled living radical polymerization techniques

Controlled living radical polymerizations, such as ATRP and RAFT polymerization, could be utilized for the preparation of well-defined organic–inorganic hybrid polymers based on POSS, PDMS, silica nanoparticles, graphene, CNTs and fullerene.

Intracellular cascade FRET for temperature imaging of living cells with polymeric ratiometric fluorescent thermometers

Intracellular temperature plays a prominent role in cellular functions and biochemical activities inside living cells, but effective intracellular temperature sensing and imaging is still in its infancy. Herein, thermoresponsive double hydrophilic block copolymers (DHBCs)-based fluorescent thermometers were fabricated to investigate their application in intracellular temperature imaging. Blue-emitting coumarin monomer, CMA, green-emitting 7-nitro-2,1,3-benzoxadiazole (NBD) monomer, NBDAE, and red-emitting rhodamine B monomer, RhBEA, were copolymerized separately with N-isopropylacrylamide (NIPAM) to afford dye-labeled PEG-b-P(NIPAM-co-CMA), PEG-b-P(NIPAM-co-NBDAE), and PEG-b-P(NIPAM-co-RhBEA). Because of the favorable fluorescence resonance energy transfer (FRET) potentials between CMA and NBDAE, NBDAE and RhBEA, as well as the slight tendency between CMA and RhBEA fluorophore pairs, three polymeric thermometers based on traditional one-step FRET were fabricated by facile mixing two of these three fluorescent DHBCs, whereas exhibiting limited advantages. Thus, two-step cascade FRET among three polymeric fluorophores was further interrogated, in which NBD acted as a bridging dye by transferring energy from CMA to RhBEA. Through the delicate optimization of the molar contents of three polymeric components, a ∼8.4-fold ratio change occurred in the temperature range of 20-44 °C, and the detection sensitivity improved significantly, reached as low as ∼0.4 °C, which definitely outperformed other one-step FRET thermometers in the intracellular temperature imaging of living cells. To our knowledge, this work represents the first example of polymeric ratiometric thermometer employing thermoresponsive polymer-based cascade FRET mechanism.

Precision synthesis of macrocyclic giant surfactants tethered with two different polyhedral oligomeric silsesquioxanes at distinct ring locations via four consecutive “click” reactions

Cyclic polymers tethered with two different nanoparticles at distinct ring locations were precisely achieved via the multiple sequential “click” strategy.

Preparation and properties of polystyrene nanocomposites containing dumbbell-shaped molecular nanoparticles based on polyhedral oligomeric silsesquioxane and [60]fullerene

POSS–C₆₀ as a novel nanofiller for polymer nanocomposites.

Thiol–ene “click” reactions and recent applications in polymer and materials synthesis: a first update

This contribution serves as an update to a previous review (Polym. Chem.2010,1, 17–36) and highlights recent applications of thiol–ene ‘click’ chemistry as an efficient tool for both polymer/materials synthesis as well as modification.

Tuning “thiol-ene” reactions toward controlled symmetry breaking in polyhedral oligomeric silsesquioxanes

A facile method toward polyhedral oligomeric silsesquioxane-based nano-building blocks with controlled symmetry breaking was reported by using thiol-ene chemistry.

Cascading One-Pot Synthesis of Single-Tailed and Asymmetric Multitailed Giant Surfactants

Rapid and precise synthesis of macromolecules has been a grand challenge in polymer chemistry. In this letter, we describe a convenient, rapid, and robust strategy for a one-pot synthesis of various precisely defined giant surfactants based on polyhedral oligomeric silsesquioxane (POSS). The method combines orthogonal oxime ligation, strain-promoted azide-alkyne cycloaddition (SPAAC), and thiol-ene "click" coupling. The process is usually completed within 0.5-2 h and does not require chromatography methods for purification. With near quantitative conversion efficiency, the method yields giant surfactants with distinct topologies, including single-tailed and asymmetric, multitailed giant surfactants. Both polymer tail composition and POSS surface chemistry are controlled precisely and tuned independently, enabling the design and preparation of new classes of giant surfactants.

Sequential Triple "Click" Approach toward Polyhedral Oligomeric Silsesquioxane-Based Multiheaded and Multitailed Giant Surfactants

This letter reports a sequential triple "click" chemistry method for the precise synthesis of functional polyhedral oligomeric silsesquioxane (POSS)-based multiheaded and multitailed giant surfactants. A vinyl POSS-based heterobifunctional building block possessing two alkyne groups of distinct reactivity was used as a robust and powerful "clickable" precursor for ready access to a variety of POSS-based shape amphiphiles with complex architectures. The synthetic approach involves sequentially performed strain-promoted azide-alkyne cycloaddition (SPAAC), copper-catalyzed azide-alkyne cycloaddition (CuAAC), and thiol-ene "click" coupling (TECC). Specifically, the first SPAAC reaction was found to be highly selective with no complications from the vinyl groups and terminal alkynes in the precursor. The method expands the toolbox of sequential "click" approaches and broadens the scope of synthetically available giant surfactants for further study on structure-property relationships.