Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• . Therefore, we considered the use of the initiator salt, i.e., the product of the stoichiometric reaction of MeOTf and a 2-oxazoline monomer. This would remove the excessive reactivity but retain the benefit of having triflate counterions for cationic polymerization. Accordingly, 2-ethyl-3-methyl-2

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• , Fukutomi, and Nakayama [19] reported the synthesis of what they described as ‘true polyazulene’ through a cationic polymerization reaction. Their protocol involved heating the trifluoroacetic acid (TFA) solution of azulene (1) followed by treatment with triethylamine to obtain a brown polymeric product

• ) complexes. Synthesis of ‘true polyazulene’ 3 or 3’ by cationic polymerization. Synthesis of 1,3-polyazulene 5 by Yamamoto protocol. Synthesis of 4,7-dibromo-6-(n-alkyl)azulenes 12–14. Synthesis of (A) 4,7-diethynyl-6-(n-dodecyl)azulene (16) and (B) 4,7-polyazulene 17 containing an ethynyl spacer. Synthesis

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• that inhibits cationic polymerization of epoxides [5]. Though conjugate acids are formed according to the routes shown in Scheme 6, cationic photopolymerization only succeeded with aziridines [5]. The different reaction mechanism occurring with such monomers explains these different observations [92

• photoproducts 33a–f did not permit successful run of cationic polymerization neither of oxiranes nor oxetanes. This became possible with the sensitizers 35–37 differing only with respect to their anion; that is [BF4]−, [PF6]− and [Al(O-t-C4F9)]− [6] after the first successful report of NIR-sensitized cationic

Synthesis of polydicyclopentadiene using the Cp₂TiCl₂/Et₂AlCl catalytic system and thin-layer oxidation of the polymer in air

• Zhargolma B. Bazarova,
• Ludmila S. Soroka,
• Alex A. Lyapkov,
• Мekhman S. Yusubov and
• Francis Verpoort

Beilstein J. Org. Chem. 2019, 15, 733–745, doi:10.3762/bjoc.15.69

• charged complexes of blue discoloration, which initiate cationic polymerization of dicyclopentadiene. Unstabilized thin layers of obtained polydicyclopentadiene undergo oxidation and structuring under atmospheric oxygen. Oxidation of polydicyclopentadiene films in air occurs slowly during several weeks

• through the layers. Consequently, this leads to the transition of the oxidation from a kinetic mode into a diffusive mode. Such structural changes do not occur in a polymer that was stabilized by adding an antioxidant. Keywords: bis(cyclopentadienyl)titanium dichloride; cationic polymerization; oxidation

• obtain a polymer with particular properties – polydicyclopentadiene (PDCPD) [8][9]. Cationic polymerization of DCPD takes place with metal-halide-based catalyst systems and organometallic compounds. A number of scientific reports were dedicated to the investigation of DCPD polymerization based on these

Organometallic vs organic photoredox catalysts for photocuring reactions in the visible region

• Aude-Héloise Bonardi,
• Frédéric Dumur,
• Guillaume Noirbent,
• Jacques Lalevée and
• Didier Gigmes

Beilstein J. Org. Chem. 2018, 14, 3025–3046, doi:10.3762/bjoc.14.282

• the case of a d5 high spin octahedral complex in Figure 4. As for LMCT, MLCT give intense band in UV spectrum. 1.4 Mechanisms in polymerization reactions Free radical polymerization or/and cationic polymerization can be initiated by photoredox catalysis. Respectively, radicals or/and cations must be

• also produced and able to initiate the free radical polymerization. Concerning the cationic polymerization, initiating cations are also produced in the three systems proposed, e.g., in the catalytic cycle (Figure 5A). Thanks to the low ionization potential of the silyl radicals (TMS)3Si•, the

• , both the polymerization rate and the final conversion were both improved by reducing the nucleophilicity of the anion in cationic polymerization. The photochemical properties of TADF CuC 4 are summarized in Table 6. From Table 6, it is observable that the properties of CuC 4 are compatible with its use

Metal and metal-free photocatalysts: mechanistic approach and application as photoinitiators of photopolymerization

• Jacques Lalevée,
• Sofia Telitel,
• Pu Xiao,
• Marc Lepeltier,
• Frédéric Dumur,
• Fabrice Morlet-Savary,
• Didier Gigmes and
• Jean-Pierre Fouassier

Beilstein J. Org. Chem. 2014, 10, 863–876, doi:10.3762/bjoc.10.83

• (R3SiH) and exhibits a relatively similar performance in photoinitiating systems of cationic polymerization [45][46][47][48][49][50][51][52][54][55]. Examples of metal-free pure organic PICs for FRP and FRPCP have also been very recently reported [54][55][61][62]. For example, they involve a violanthrone

• under a red laser line exposure at 635 nm. This result was very important as cationic polymerization in these irradiation conditions was not possible previously. Changing Vi or the anthracene derivative for a hydrocarbon (e.g. pyrene, naphthacene, pentacene) allows a tunable absorption of the system

• ; Scheme 11) [64]. All these described systems, producing radicals, cations or radical cations, allow efficient CP and FRPCP of cationic monomers, FRP of acrylates, simultaneous radical/cationic polymerization of epoxide/acrylate blend. The reactions can be carried out (see in [45][46][47][48][49][50][51

New core-pyrene π structure organophotocatalysts usable as highly efficient photoinitiators

• Sofia Telitel,
• Frédéric Dumur,
• Thomas Faury,
• Bernadette Graff,
• Mohamad-Ali Tehfe,
• Didier Gigmes,
• Jean-Pierre Fouassier and
• Jacques Lalevée

Beilstein J. Org. Chem. 2013, 9, 877–890, doi:10.3762/bjoc.9.101

• Scheme 1). Secondly, PIs may be used in free-radical-promoted cationic polymerization (FRPCP), in which the produced radical R• is oxidized by an onium salt, e.g., Ar2I+, to form Ar2I• and a cation R+ suitable for the ROP reaction. The Ar2I• species is readily decomposed into ArI and Ar• (r2 in Scheme 1

• ). There is also an usual cationic polymerization (CP; r3 in Scheme 1) [1][2]. When the PIs exhibit a catalytic behavior analogous to a photocatalyst (PC) in organic chemistry, they are designed as photoinitiator catalysts (PIC). PIs as well as PICs are based on pure organic, that is, metal free, or

• . The large choice of Co_Pys should allow for studying the effect of the core on the MO coupling and the resulting absorption properties. The activity of these Co_Py compounds in the FRP of acrylates and the FRPCP (and eventually the cationic polymerization CP) of epoxides through a ring-opening

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• (methylhydrogenosiloxane), and multiblock vinyl functionalized silicones, respectively. Oligomers of phenyl glycidyl ether were produced in direct miniemulsion initiated by the counter anion of the surfmer didodecyldimethyl ammmonium hydroxide [78]. Cationic polymerization can also be performed in direct miniemulsion in

• surfactant did not play the expected role, since the p-MOS-HCl was hydrolyzed. The resulting hydronium ion protonated the SDS surfactant, which acted as an inisurf in the interfacial cationic polymerization process. Alkyl cyanoacrylate monomers are probably the simplest monomers to polymerize anionically

Synthesis and crystal structures of multifunctional tosylates as basis for star-shaped poly(2-ethyl-2-oxazoline)s

• Richard Hoogenboom,
• Martin W. M. Fijten,
• Guido Kickelbick and
• Ulrich S. Schubert

Beilstein J. Org. Chem. 2010, 6, 773–783, doi:10.3762/bjoc.6.96

• initiator was prepared, which yielded a well-defined star-shaped poly(2-ethyl-2-oxazoline) by CROP as demonstrated by SEC with RI, UV and diode-array detectors, as well as by 1H NMR spectroscopy. Keywords: cationic polymerization; crystal structure; living polymerization; star-polymer; tosylate

Novel multi-responsive P2VP-block-PNIPAAm block copolymers via nitroxide-mediated radical polymerization

• Cathrin Corten,
• Katja Kretschmer and
• Dirk Kuckling

Beilstein J. Org. Chem. 2010, 6, 756–765, doi:10.3762/bjoc.6.89

• smart block and graft copolymers are already known in the literature [9]. Block copolymers in a wide range of variety are synthesized by using living anionic polymerization [10], living cationic polymerization [11] or controlled radical polymerizations techniques [12]. The development of the controlled

New amphiphilic glycopolymers by click functionalization of random copolymers – application to the colloidal stabilisation of polymer nanoparticles and their interaction with concanavalin A lectin

• Otman Otman,
• Paul Boullanger,
• Eric Drockenmuller and
• Thierry Hamaide

Beilstein J. Org. Chem. 2010, 6, No. 58, doi:10.3762/bjoc.6.58

• surfactants for mini-emulsion polymerization [5][6]. Amphiphilic block copolymers with pendant glucosamine units have been obtained by living cationic polymerization and their interaction with wheat germ agglutinin lectin investigated [7]. More recently, the synthesis of neoglycopolymers by living radical