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A straightforward approach is employed to synthesize methylene‐bridged poly(hetero aromatic)s based on furan, pyrrole, thiophene, and thiophene derivatives. The process involves an electrophilic aromatic substitution reaction facilitated by a visible light‐initiated system consisting of manganese decacarbonyl and an iodonium salt. The approach mainly relies on the formation of halomethylium cation, the attack of this cation to heteroaromatic, regeneration of methylium cation on the heteroaromatic, and reactivity differences between halomethylium and heteroaromatic methylium cations for successful polymerizations. This innovative synthetic strategy lead to the formation of polymers with relatively high molecular weights as the stoichiometric imbalance between the comonomers increased. Accordingly, these newly obtained polymers exhibit remarkable fluorescence properties, even at excitation wavelengths as low as 330 nm. Moreover, by harnessing the halogens at chain ends of homopolymers, block copolymers are successfully synthesized, offering opportunities for tailored applications in diverse fields. [ABSTRACT FROM AUTHOR]

With the advantages offered by cationic photopolymerization (CP) such as broad wavelength activation, tolerance to oxygen, low shrinkage and the possibility of "dark cure", it has attracted extensive attention in photoresist, deep curing and other fields in recent years. The applied photoinitiating systems (PIS) play a crucial role as they can affect the speed and type of the polymerization and properties of the materials formed. In the past few decades, much effort has been invested into developing cationic photoinitiating systems (CPISs) that can be activated at long wavelengths and overcome technical problems and challenges faced. In this article, the latest developments in the long wavelength sensitive CPIS under ultraviolet (UV)/visible light-emitting diodes (LED) lights are reviewed. The objective is, furthermore, to show differences as well as parallels between different PIS and future perspectives. [ABSTRACT FROM AUTHOR]

Treatment of N‐methyl‐S,S‐diaryl sulfoximines with methyl trifluoromethanesulfonate provides bench‐stable sulfoxinium salts in excellent yields. Applying them in Sonogashira‐, Heck‐ and Suzuki‐type cross‐coupling reactions leads to the corresponding products by sequential C−S bond cleavage and C−C bond formation. Electronic factors induced by substituents on the S‐aryl groups govern the coupling efficiency. [ABSTRACT FROM AUTHOR]

Epoxides are frequently used in coatings due to their great adhesion to most materials, high resistance towards chemicals and well‐defined material properties. Onium salts such as iodonium and sulfonium salts are one of the most widespread classes of initiators used in light‐induced cationic polymerization of such epoxides. We successfully synthesized onium salts based on group 14 to 16 elements in the periodic table. They were then characterized using cyclic voltammetry and UV–visible spectroscopy before determining their reactivity in epoxy‐based resins. Using commercial bisphenol‐A‐based resins, thiopyrylium, bismuithonium and pyrylium salts show good reactivity and epoxy group conversions above 60% in simultaneous thermal analysis. Photochemically interesting new cationic initiators were identified to be oxonium, thiopyrylium and selenonium salts. Additionally, bismuthonium and stibonium salts show great potential towards sensitization with anthracene. © 2021 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

With the advantages offered by cationic photopolymerization (CP) such as broad wavelength activation, tolerance to oxygen, low shrinkage and the possibility of “dark cure”, it has attracted extensive attention in photoresist, deep curing and other fields in recent years. The applied photoinitiating systems (PIS) play a crucial role as they can affect the speed and type of the polymerization and properties of the materials formed. In the past few decades, much effort has been invested into developing cationic photoinitiating systems (CPISs) that can be activated at long wavelengths and overcome technical problems and challenges faced. In this article, the latest developments in the long wavelength sensitive CPIS under ultraviolet (UV)/visible light-emitting diodes (LED) lights are reviewed. The objective is, furthermore, to show differences as well as parallels between different PIS and future perspectives.

Recent knowledge in chemistry has enabled the material utilization of greenhouse gas (CO2) for the production of organic carbonates using mild reaction conditions. Organic carbonates, especially cyclic carbonates, are applicable as green solvents, electrolytes in batteries, feedstock for fine chemicals and monomers for polycarbonate production. This review summarizes new developments in the ring opening of epoxides with subsequent CO2-based formation of cyclic carbonates. The review highlights recent and major developments for sustainable CO2 conversion from 2000 to the end of 2021 abstracted by Web of Science. The syntheses of epoxides, especially from bio-based raw materials, will be summarized, such as the types of raw material (vegetable oils or their esters) and the reaction conditions. The aim of this review is also to summarize and to compare the types of homogeneous non-metallic catalysts. The three reaction mechanisms for cyclic carbonate formation are presented, namely activation of the epoxide ring, CO2 activation and dual activation. Usually most effective catalysts described in the literature consist of powerful sources of nucleophile such as onium salt, of hydrogen bond donors and of tertiary amines used to combine epoxide activation for facile epoxide ring opening and CO2 activation for the subsequent smooth addition reaction and ring closure. The most active catalytic systems are capable of activating even internal epoxides such as epoxidized unsaturated fatty acid derivatives for the cycloaddition of CO2 under relatively mild conditions. In case of terminal epoxides such as epichlorohydrin, the effective utilization of diluted sources of CO2 such as flue gas is possible using the most active organocatalysts even at ambient pressure. [ABSTRACT FROM AUTHOR]

After the 20‐year dormant period since Liebeskind's seminal report, triorganosulfonium salts have now proved to be reliably useful surrogates of or complement to organic halides in a variety of transition‐metal‐catalyzed transformations. By necessity, my group developed Suzuki‐Miyaura ring‐opening arylation of sulfonium salts of dibenzothiophenes with tetraarylborates and Pd‐catalyzed intramolecular C−H/C−S coupling. Following this starting point and experiencing the decent reactivity of sulfonium salts, in order to maximize the synthetic utility of organosulfur compounds, we successfully applied readily available sulfonium salts to Ni‐catalyzed coupling with arylzinc reagents, Pd‐ or photoredox‐catalyzed Mizoroki‐Heck reaction, Pd‐catalyzed alkoxycarbonylation, Pd‐catalyzed Miyaura borylation, Ni‐catalyzed reductive carboxylation, and Ni‐catalyzed zincation. I sincerely hope this Personal Account will facilitate further development of reactions of triorganosulfonium salts which are difficult to achieve using conventional organic (pseudo)halides. [ABSTRACT FROM AUTHOR]

Recent knowledge in chemistry has enabled the material utilization of greenhouse gas (CO2) for the production of organic carbonates using mild reaction conditions. Organic carbonates, especially cyclic carbonates, are applicable as green solvents, electrolytes in batteries, feedstock for fine chemicals and monomers for polycarbonate production. This review summarizes new developments in the ring opening of epoxides with subsequent CO2-based formation of cyclic carbonates. The review highlights recent and major developments for sustainable CO2 conversion from 2000 to the end of 2021 abstracted by Web of Science. The syntheses of epoxides, especially from bio-based raw materials, will be summarized, such as the types of raw material (vegetable oils or their esters) and the reaction conditions. The aim of this review is also to summarize and to compare the types of homogeneous non-metallic catalysts. The three reaction mechanisms for cyclic carbonate formation are presented, namely activation of the epoxide ring, CO2 activation and dual activation. Usually most effective catalysts described in the literature consist of powerful sources of nucleophile such as onium salt, of hydrogen bond donors and of tertiary amines used to combine epoxide activation for facile epoxide ring opening and CO2 activation for the subsequent smooth addition reaction and ring closure. The most active catalytic systems are capable of activating even internal epoxides such as epoxidized unsaturated fatty acid derivatives for the cycloaddition of CO2 under relatively mild conditions. In case of terminal epoxides such as epichlorohydrin, the effective utilization of diluted sources of CO2 such as flue gas is possible using the most active organocatalysts even at ambient pressure.

Abstract The aim of this study was to analyze the efficiency of experimental light-curing resin cements (ERCs) with a ternary photo-initiator system containing diphenyliodonium hexafluorphosphate (DPI) and different amines on retention of glass-fiber posts to dentin (GFP). ERCs formulations: a 1:1 mass ratio of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenylpropane and triethyleneglycol dimethacrylate. Camphorquinone was used as initiator. Six experimental groups were established according to the amine used: [ethyl-4-(dimethylamino)benzoate-EDMAB or 2-(dimethylamino)ethyl methacrylate-DMAEMA] and the concentration of DPI (0, 0.5 mol%, 1 mol%). The resin cements Variolink II (dual- and light-cured versions) were used as commercial reference. Eighty recently extracted bovine incisors (n = 10) were selected for this study. The roots were prepared and the fiber posts were cemented with the resin cement specified for each experimental group. Specimens from coronal, middle, and apical thirds of the root were subjected to push-out bond strength test 24 hours after bonding. Data were subjected to split-plot ANOVA and the Tukey test (p = 0.05). ERCs containing DPI showed statistically significant higher bond strengths compared with ERCs without DPI. ERCs containing DPI were statistically similar to VARIOLINK II – dual-cured and superior to VARIOLINK II – light-cured (except for EDMAB – 1DPI in the medium third and DMAEMA – 1DPI in the coronal third). Different amines did not influence post retention. The apical root region showed the lowest bond strength for the groups EDAB-0DPI, DMAEMA-0DPI and VARIOLINK II light-cured. Light-cured ERCs containing DPI were efficient for GFP retention to radicular dentin, with similar behaviour to that of dual-curing commercial resin cement.

The aim of this study was to analyze the efficiency of experimental light-curing resin cements (ERCs) with a ternary photo-initiator system containing diphenyliodonium hexafluorphosphate (DPI) and different amines on retention of glass-fiber posts to dentin (GFP). ERCs formulations: a 1:1 mass ratio of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenylpropane and triethyleneglycol dimethacrylate. Camphorquinone was used as initiator. Six experimental groups were established according to the amine used: [ethyl-4-(dimethylamino)benzoate- EDMAB or 2-(dimethylamino)ethyl methacrylate-DMAEMA] and the concentration of DPI (0, 0.5 mol%, 1 mol%). The resin cements Variolink II (dual- and light-cured versions) were used as commercial reference. Eighty recently extracted bovine incisors (n = 10) were selected for this study. The roots were prepared and the fiber posts were cemented with the resin cement specified for each experimental group. Specimens from coronal, middle, and apical thirds of the root were subjected to push-out bond strength test 24 hours after bonding. Data were subjected to split-plot ANOVA and the Tukey test (p = 0.05). ERCs containing DPI showed statistically significant higher bond strengths compared with ERCs without DPI. ERCs containing DPI were statistically similar to VARIOLINK II - dual-cured and superior to VARIOLINK II - light-cured (except for EDMAB - 1DPI in the medium third and DMAEMA - 1DPI in the coronal third). Different amines did not influence post retention. The apical root region showed the lowest bond strength for the groups EDAB-0DPI, DMAEMA-0DPI and VARIOLINK II light-cured. Light-cured ERCs containing DPI were efficient for GFP retention to radicular dentin, with similar behaviour to that of dual-curing commercial resin cement. [ABSTRACT FROM AUTHOR]

Palladium nanoparticles, simply and briefly generated in commercial and cheap onium salts using supercritical carbon dioxide, have been found to be an effective catalytic system for additive free N-alkylation reaction using alcohols via cascade oxidation/condensation/reduction steps. [ABSTRACT FROM AUTHOR]

Metal nanocrystals have been prepared in onium salts using supercritical carbon dioxide assisted synthesis. During the process, metal salts precursors are reduced by H 2 in an organic solvent free media, the onium salts allowing both the stabilization of the nanostructured material and the preparation of an air and moisture stable powder made of embedded metal nanocrystals. Those catalysts proved to be highly effective in the hydroboration of alkyne process. [ABSTRACT FROM AUTHOR]

Data of potentiometric, redox, and conductometric studies of interactions in the sulfur(IV) oxide-ethylenediamine (or its analogs)-water systems, being in fair agreement, have showed the formation of onium sulfites, hydrosulfites, and pyrosulfites. The absorbance capacity of aqueous solutions of ethylenediamines with respect to sulfur dioxide depends on the amino groups amount. Ion and molecular compositions of the studied solutions have been computed, and the relative stability of onium sulfites of ethylenediamine and piperazine has been estimated. [ABSTRACT FROM AUTHOR]

Palladium nanoparticles, simply and briefly generated in commercial and cheap onium salts using supercritical carbon dioxide, have been found to be an effective catalytic system for additive free N-alkylation reaction using alcohols via cascade oxidation/condensation/reduction steps.

Abstract: Although quaternary onium salt-catalyzed phase-transfer reactions are generally believed to require base additives, we discovered even without any base additives conjugate additions of 3-substituted oxindoles proceeded smoothly in the presence of lipophilic quaternary onium bromide under water-organic biphasic conditions. The mechanism of this novel base-free neutral phase-transfer reaction system was investigated, and the assumed catalytic cycle was presented together with interesting effects of water and lipophilicity of the phase-transfer catalyst. The base-free neutral phase-transfer reaction system could be applied to highly enantioselective conjugate additions, aldol reaction, sulfenylation, and chlorination under the influence of chiral bifunctional onium bromides as key catalysts. [Copyright &y& Elsevier]

Abstract: Objective: This study evaluated the effect of adding diphenyliodonium hexafluorphosphate (DPI) as a third component of the free-radical photoinitiator system of model resin cements on their photopolymerization kinetics/stress and fundamental properties. Methods: A model resin cement containing a 1:1 mass ratio of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane and triethyleneglycol dimethacrylate was obtained. Camphorquinone (1mol%) and 2-(dimethylamino)ethyl methacrylate (2mol%) were added to monomer blend. Six mixtures were obtained by incorporation of 0 (control), 0.25, 0.5, 1, 2, or 4mol% of DPI. The cements were loaded with a 60% mass fraction of silanated glass fillers. Polymerization kinetics (using Fourier-transform near-infrared spectroscopy), flexural strength and modulus, water uptake/solubility, and polymerization stress were assessed. Data were statistically analyzed using one-way ANOVA and Student–Newman–Keuls’ test (P ≤0.05). Results: In the DPI-modified materials, the onset of autodeceleration occurred earlier and at higher conversion compared with the control cement. The addition of DPI also led to a more active early-stage polymerization. The flexural modulus was generally higher for DPI-containing materials. Water uptake and solubility were generally lower for materials with DPI fractions ≥0.5%. Significant increase of polymerization stress was observed only in the group with 1mol% of DPI compared with the control cement. Significance: The effect of DPI on the photopolymerization reactivity of the cement is concentration-dependent; the use of DPI could result in better polymerization efficiency of resin-based cements. [Copyright &y& Elsevier]

Abstract: A novel cationic photoinitiator namely, 2-benzyl-2-(N,N-dimethyl-2-oxo-2-phenylethyl) ammonium hexafluoroantimonate-1-(4-morpholinophenyl)-butane-1-one (BDMPP+ ), carrying two photochromophoric groups was synthesized and characterized. Theoretical absorption characteristics of the salt were studied and compared with those obtained experimentally. Photoinitiation activity of this salt was demonstrated by polymerization of various monomers at λ =350nm. Upon irradiation by UV light, cationic species formed from homolytic dissociation followed by electron transfer or directly by heterolytic scission initiate cationic polymerization. [Copyright &y& Elsevier]

The aim of present study is to examine the photo-initiation efficiency of N, N-dimethylacrylamide-based allylic ammonium salt as one component addition-fragmentation agent (cationic photoinitiator cum radical source) in free radical accelerated cationic polymerization. Novel addition-fragmentation agent (AFA), 2-( N, N-dimethylcarboxy-3-propenyl)(phenylcarbonyl-4-phenylene) dimethyl ammonium hexafluoroantimonate (DMPDA) was synthesized as cationic photoinitiator and its initiation efficiency was examined in polymerization of cyclohexene oxide (CHO), isobutyl vinyl ether (IBVE), and n-butyl vinyl ether ( n-BVE) in CH2Cl2 solvent at wavelength λ > 290 nm. The rate of polymerization increases with the increase in initiator concentration and reaction time. The results demonstrate that DMPDA acts as an efficient photoinitiator (AFA) without use of radical source in free radical accelerated cationic polymerization. [ABSTRACT FROM AUTHOR]

Abstract: Efficient catalytic systems based on the combination of cobalt(II)/onium salts for the coupling reaction of CO2 and epoxides are reported. The catalytic systems work under mild reaction conditions (e.g. 10bar and 120°C) and produce cyclic carbonates with high turnover frequencies (TOF) and selectivity. From a series of onium salts, bis(triphenylphosphoranylidene)ammonium chloride proved to be the most active cocatalyst (TOF=2314), while tetrabutyl ammonium chloride (TOF=2223) and 1,3-bis(2,4,6trimethylphenyl)imidazolium chloride (TOF=2174) provided only slightly reduced activities under similar conditions. The influence of various reaction parameters including CO2 pressure, reaction temperature and loading of onium salt was determined. In order to obtain an insight into the catalytic process, the reaction was followed by electrospray ionisation-mass spectrometry. Additionally, in situ FT-IR measurements show that the catalyst is stable even with low loading (0.025mol%) and as a result, the reaction proceeds steadily over several hours. [Copyright &y& Elsevier]

This study evaluated the effect of organic solvent concentration on the polymerization kinetics for a model dental adhesive resin containing a ternary photoinitiator system. A monomer blend based on the bis‐GMA, TEGDMA, and HEMA was used as a model dental adhesive resin, which was polymerized using a binary system [camphorquinone (CQ) and ethyl 4‐dimethylamine benzoate (EDAB)] and a ternary system [CQ, EDAB, and diphenyliodonium hexafluorphosphate (DPIHFP)]. Additionally, these blends had 0, 10, 20, 30, and 40 wt % ethanol added. Real‐time Fourier transform infrared spectroscopy was used to investigate the polymerization reaction over photoactivation time. Data were plotted, and Hill's three‐parameter nonlinear regression was performed for curve fitting. The addition of a solvent to the monomer blends decreased the polymerization kinetics, directly affecting the rate of polymerization, delaying vitrification, and attenuating the Trommsdorf effect. The introduction of DPIHFP displayed a strong increase in reaction kinetics, reducing the solvent inhibition effect. After 10 s of photoactivation, the binary system obtained in 0, 10, 20, 30, and 40% of ethanol, a degree of conversion of 44.6, 26.3, 13.4, 1.15, and 0.0%, respectively, whereas when a ternary system was used, the values were 54.6, 40.5, 27.4, 14.5, and 3.4%. An improvement was observed in the polymerization kinetics of a model dental adhesive resin when using a ternary photoinitiation system, making the material less sensitive to the residual presence of a solvent before photoactivation. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to evaluate the influence of an onium salt in the polymerization kinetics of a dental adhesive model resin. A monomer mixture, based on Bis-GMA, TEGDMA and HEMA, was used as a model dental adhesive resin, which was polymerized using camphorquinone (CQ) as a photo-initiator in addition to either binary or ternary photo-initiator systems. The binary systems were formulated with different concentrations of diphenyliodonium hexafluorphosphate or ethyl 4-dimethylaminobenzoate in relation to the monomer and 1mol% of CQ. The ternary system was a blend of 1mol% of CQ, 2mol% of ethyl 4-dimethylamino benzoate and 0.25, 0.5, 1, 2 or 4mol% of onium salt. Real time Fourier Transform infrared spectroscopy was used to investigate the polymerization reaction over the photo-activation time. When CQ was used as photo-initiator, a slow polymerization reaction was observed and a lower monomer conversion. The addition of a second component (onium salt or amine) increases the polymerization rate and conversion independent on the co-initiator concentration. Ternary photo-initiator system showed an improvement on the polymerization rate of the dental adhesive model resin leading to high conversion in short photo-activation time. Also, a mechanism for initiating polymerization using an amine or onium salt as a co-initiator component is proposed. [Copyright &y& Elsevier]

After the 20-year dormant period since Liebeskind's seminal report, triorganosulfonium salts have now proved to be reliably useful surrogates of or complement to organic halides in a variety of transition-metal-catalyzed transformations. By necessity, my group developed Suzuki-Miyaura ring-opening arylation of sulfonium salts of dibenzothiophenes with tetraarylborates and Pd-catalyzed intramolecular C-H/C-S coupling. Following this starting point and experiencing the decent reactivity of sulfonium salts, in order to maximize the synthetic utility of organosulfur compounds, we successfully applied readily available sulfonium salts to Ni-catalyzed coupling with arylzinc reagents, Pd- or photoredox-catalyzed Mizoroki-Heck reaction, Pd-catalyzed alkoxycarbonylation, Pd-catalyzed Miyaura borylation, Ni-catalyzed reductive carboxylation, and Ni-catalyzed zincation. I sincerely hope this Personal Account will facilitate further development of reactions of triorganosulfonium salts which are difficult to achieve using conventional organic (pseudo)halides., (© 2021 The Chemical Society of Japan & Wiley-VCH GmbH.)

• Tuning of the Fermi level of SWCNTs was achieved by using onium salts. • Onium salts with a smaller substituent on the cation and a lower nucleophilic anion enhanced hole doping to SWCNTs. • Electron doping to SWCNTs proceeded with onium salts with a larger substituent on the cation and a higher nucleophilic anion. • The power factor of SWCNTs doped with NH4+Cl- was improved by about 7 times compared to SWCNTs without doping treatment. Fermi level is one of the most important parameters for control of semiconductor polarity and improvement of thermoelectric performances. Although single-walled carbon nanotubes (SWCNTs) are promising candidates for thermoelectric materials, control of the Fermi level of SWCNTs with chemical dopants is still challenging. Reported here is the fine-tuning of the Fermi level of SWCNTs with onium salts. The Fermi level of SWCNTs was very sensitive to substituent size on the cation and nucleophilicity of the anion, and the Seebeck coefficients markedly changed between −50 μV K−1 and 68 μV K−1. The optimum Fermi level of p-type SWCNTs that exhibits the maximum power factor was realized by ammonium chloride or pyridine hydrochloride, and the power factor (PF) was improved by about 7 times as compared with non-doped SWCNTs. SWCNTs doped with onium salts were stable in both p-type and n-type states, and thermoelectric performances did not change more than 100 days in the air. [ABSTRACT FROM AUTHOR]