A highly efficient photomediated atom transfer radical polymerization protocol is reported for semi-fluorinated acrylates and methacrylates. Use of the commercially available solvent, 2-trifluoromethyl-2-propanol, optimally balances monomer, polymer, and catalyst solubility while eliminating transesterification as a detrimental side reaction. In the presence of UV irradiation and ppm concentrations of copper(II) bromide and Me-TREN (TREN = tris(2-aminoethyl amine)), semi-fluorinated monomers with side chains containing between three and 21 fluorine atoms readily polymerize under controlled conditions. The resulting polymers exhibit narrow molar mass distributions (Đ ≈ 1.1) and high end group fidelity, even at conversions greater than 95%. This level of control permits the in situ generation of chain-end functional homopolymers and diblock copolymers, providing facile access to semi-fluorinated macromolecules using a single methodology with unprecedented monomer scope. The results disclosed herein should create opportunities across a variety of fields that exploit fluorine-containing polymers for tailored bulk, interfacial, and solution properties.

We present a new ambient temperature synthetic approach for the preparation of single-chain polymeric nanoparticles (SCNPs) under mild conditions using a UV-light-triggered Diels–Alder (DA) reaction for the intramolecular cross-linking of single polymer chains. Well-defined random copolymers with varying contents of styrene (S) and 4-chloromethylstyrene (CMS) were synthesized employing a nitroxide-mediated radical polymerization (NMP) initiator functionalized with a terminal alkyne moiety. Postpolymerization modification with 4-hydroxy-2,5-dimethylbenzophenone (DMBP) and an N-maleimide (Mal) derivative led to the functional linear precursor copolymers. The intramolecular cross-linking was performed by activating the DMBP groups via irradiation with UV light of 320 nm for 30 min in diluted solution (c Polymer = 0.017 mg mL–1). The ensuing DA reaction between the activated DMBP and the Mal groups resulted in well-defined single-chain polymeric nanoparticles. To control the size of the SCNPs, random copolymers with varying CMS contents (i.e., different functional group densities (FGD)) were employed for the single-chain collapse. Additionally, monotethered nanoparticles were prepared via the copper-catalyzed azide–alkyne cycloaddition between the alkyne bearing copolymer with the highest FGD and an azide-terminated poly(ethylene glycol) (PEG) prior to UV-induced cross-linking. The formation of SCNPs was followed by size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM).

Usually atom transfer radical polymerization (ATRP) requires various parameters, such as the type of initiator, transition metal, ligand, solvent, temperature, deactivator, added salts and reducing agents, need to be optimised in order to achieve a high degree of control over molecular weight and dispersity. These components play a major role when switching monomers e.g. from acrylic to methacrylic and/or styrenic monomers during the synthesis of homo-and block copolymers as the stability and reactivity of the carbon centered propagating radical dramatically changes. This is a challenge for both "experts" and non-experts as choosing the appropriate conditions for successful polymerization can be time consuming and an arduous task. In this work we describe some universal conditions for the efficacious polymerization of acrylates, methacrylates and styrene (using an identical initiator, ligand, copper salt and solvent) based on commercially available reagents (PMDETA, IPA, Cu(0) wire). The versatility of these conditions is demonstrated by the near quantitative polymerization of these monomer families to yield well-defined materials over a range of molecular weights with low dispersities (~1.1-1.2). The control and high end group fidelity is further exemplified by in situ block copolymerization upon sequential monomer addition for the case of methacrylates and styrene furnishing higher molecular weight copolymers with minimal termination. The facile nature of these conditions, combined with readily available reagents will greatly expand the access and availability of tailored polymeric materials to all researchers.

The preparation and in-depth characterization of well-defined, palladium(ii) crosslinked single-chain nanoparticles (Pd-SCNPs) is reported. In addition, a novel procedure for interpreting the SEC chromatograms of SCNPs by log-normal distribution (LND) simulations is introduced.

We introduce the synthesis and in-depth characterization of platinum(II)-crosslinked single-chain nanoparticles (Pt -SCNPs) to demonstrate their application as a recyclable homogeneous catalyst. Specifically, a linear precursor copolymer of styrene and 4-(diphenylphosphino)styrene was synthesized via nitroxide-mediated polymerization. The triarylphosphine ligand moieties along the backbone allowed for the intramolecular crosslinking of single chains via the addition of [Pt(1,5-cyclooctadiene)Cl ] in dilute solution. The successful formation of well-defined Pt -SCNPs was evidenced by size exclusion chromatography, dynamic light scattering, nuclear magnetic resonance ( H, P{ H}, Pt), and diffusion-ordered spectroscopy. Finally, the activity of the Pt -SCNPs as homogeneous, yet recyclable catalyst was successfully demonstrated using the example of the amination of allyl alcohol.

The scope and accessibility of sequence-controlled multiblock copolymers is demonstrated by direct "in situ" polymerization of hydrophobic, hydrophilic and fluorinated monomers. Key to the success of this strategy is the ability to synthesize ABCDE, EDCBA and EDCBABCDE sequences with high monomer conversions (>98 %) through iterative monomer additions, yielding excellent block purity and low overall molar mass dispersities (Ð<1.16). Small-angle X-ray scattering showed that certain sequences can form well-ordered mesostructures. This synthetic approach constitutes a simple and versatile platform for expanding the availability of tailored polymeric materials from readily available monomers.

We report the facile ambient temperature generation of size tunable and well-defined (pro)fluorescent single-chain nanoparticles (SCNPs) via the photoinduced nitrile imine intramolecular cross-ligation of linear precursor polymers, constituting a platform technology as novel imaging agents. A set of three linear precursor polymers (M n ≈ 14000 g mol −1 , Đ ≈ 1.25) was synthesized via nitroxide-mediated statistical copolymerization of styrene and 4-(chloromethyl)styrene (CMS), followed by a postpolymerization modification of the resulting copolymer installing protected maleimide (PG-Mal) as well as tetrazole (Tet) moieties. The tetrazole content (% Tet) along the lateral polymer chains was varied between 12 and 24% in order to preselect not only the size of the corresponding SCNPs, but also their fluorescence and reactive properties. Finally, the applicability of the profluorescent SCNPs for fluorescence labeling was demonstrated utilizing residual surface expressed Tet moieties on the SCNPs surface in a reaction with maleimide functional polymeric microspheres. The (pro)fluorescent single-chain nanoparticles were in-depth characterized by 1 H NMR spectroscopy, dynamic light scattering (DLS), size exclusion chromatography (SEC), and atomic force microscopy (AFM), as well as UV/vis and fluorescence spectroscopy. S ingle-chain nanoparticles (SCNPs) with diameters <20 nm, prepared via intramolecular cross-linking of single polymer chains, have attracted significant attention over the past few years due to their potential applications in catalysis, sensing, and drug delivery. 1−3 A further attractive area of their application is as cell transport and imaging agents, yet no viable, size tunable, and easy to prepare nanoparticle systems that display fluorescence and the corresponding excitation in the visible light region exist. Together with examples for polymer chains that have been folded at selective points along the backbone, 4−6 such single-chain architectures can be additionally regarded as potential synthetic mimics of proteins or peptides. The intramolecular cross-links in SCNPs can for instance be dynamic, 7,8 dynamic-covalent, 9,10 or covalent. 11−13 For covalently cross-linked SCNPs, to the best of our knowledge, only a small number of examples exists that take advantage of mild, phototriggered cross-linking approaches, and none present inherent fluorescent properties. 14−16 An example for fluorescent SCNPs was published by Oria et al. in 2010. 11 However, the fluorescence properties had to be imparted by employing a suitable cross-linker, and the fluorescence (391 and 410 nm), which has to be excited at λ exc = 390 nm, is not suitable for biological applications.In the present contribution, we introduce a powerful, intramolecular cross-linking chemistry for the fast preparation of inherently (pro)fluorescent SCNPs, which is based on the photoinduced nitrile imine mediated tetrazole-ene cycloaddition (NITEC). 17,18 UV-irradiation of tetrazole derivatives leads to the formation of nitrile imines, which are ...

The versatile and high yielding end-functionalization with a varienty of functional groups is presented for poly(acrylates) obtained by ATRP.