Rare Earth Metal-Mediated Precision Polymerization of Vinylphosphonates and Conjugated Nitrogen-Containing Vinyl Monomers.

This review focuses on introducing and explaining the rare earth metal-mediated group transfer polymerization (REM-GTP) of polar monomers and is composed of three main sections: poly(vinylphosphonate)s, surface-initiated group transfer polymerization (SI-GTP), and extension to N-coordinating Michael-type monomers (2-vinylpridine (2VP), 2-isopropenyl-2-oxazoline (IPOx)). The poly(vinylphosphonate)s section is divided into two parts: radical, anionic, and silyl ketene acetal group transfer polymerization (SKA-GTP) of vinylphosphonates in comparison to REM-GTP, and properties of poly(vinylphosphonate)s. The mechanism of vinylphosphonate REM-GTP is discussed in detail for initiation and propagation including activation enthalpies ΔH(‡) and entropies ΔS(‡) according to the Eyring equation.

Mechanistic studies on initiation and propagation of rare earth metal-mediated group transfer polymerization of vinylphosphonates.

Initiation of rare earth metal-mediated vinylphosphonate polymerization with unbridged rare earth metallocenes (Cp2LnX) follows a complex reaction pathway. Depending on the nature of X, initiation can proceed either via abstraction of the acidic α-CH of the vinylphosphonate (e.g.

Rare earth metal-mediated group-transfer polymerization: from defined polymer microstructures to high-precision nano-scaled objects.

Poly(2-isopropenyl-2-oxazoline) (PIPOx) and poly(2-vinylpyridine) (P2VP) have been efficiently synthesized using bis(cyclopentadienyl)methylytterbium (Cp2YbMe) as catalyst. The polymerizations of 2-isopropenyl-2-oxazoline (IPOx) and 2-vinylpyridine (2VP) follow a living group-transfer polymerization (GTP) mechanism, allowing a precise molecular-weight control of both polymers with very narrow molecular-weight distribution. The GTP of IPOx and 2VP occurs via N coordination at the rare earth metal center, which has rarely been reported previously.

Organic-Inorganic Hybrid Nanoparticles via Photoinduced Micellation and Siloxane Core Cross-Linking of Stimuli-Responsive Copolymers.

Photoacid-induced siloxane cross-linking of stimuli-responsive copolymer micelles allows the synthesis of well-defined organic-inorganic hybrid nanoparticles. Two conceptually different synthetic approaches are presented, both via photoinduced cross-linking of poly(4-hydroxystyrene--styrene) micelles and via photoacid-catalyzed micelle formation and siloxane cross-linking of poly(4--butoxystyrene--styrene). The synthetic route showed intermicellar cross-linking leading to agglomerates.

Rare Earth metal-mediated group transfer polymerization of vinylphosphonates.

Recent studies have shown that poly(vinylphosphonate)s are readily accessible by rare earth metal-mediated group transfer polymerization (GTP). This article highlights the progress in this new field and advantages of GTP in comparison to classical anionic and radical polymerization approaches. Late lanthanide metallocenes proved to be efficient initiators and highly active catalysts for vinylphosphonate polymerization yielding polymers of precise molecular weight and low polydispersity.