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Atom transfer radical addition of alkyl halides to alkenes was developed using a low amount of a stable initiator, amine borane complexes.

In this work, we report for the first time on the influence of the quality of reactants and reaction conditions on the production of hydrophobically modified ethoxylated urethanes (HEURs) and selected prepolymers without the use of solvents. We show that the polyol water concentration is detrimental to the progress of the main urethane forming reaction, confirming the necessity of carefully drying the reactants below 1000 ppm to suppress the consumption of diisocyanate toward urea during HEUR synthesis. Increasing the mixing speed (≈30 to 750 rpm), reaction temperature (80-110 °C), and catalyst concentration (0.035-2.1 wt % bismuth carboxylate) can significantly increase the rate of molecular weight buildup, but their effect decreases with time as the bulk viscosity increases and mixing limitations eventually take over, leading to the Weissenberg effect and chain growth termination. Consequently, for the selected formulation, the maximum product molecular weight attained lies in the range of ≈20 000-22 000 g/mol, irrespective of the specific process conditions applied. ispartof: ACS OMEGA vol:7 issue:41 pages:36567-36578 ispartof: location:United States status: published

ECE-type pincer complexes have evolved into a diverse family of compounds possessing interesting structural/bonding features, reactivities, and practical applications. An important factor promoting...

International audience; α,ω-Bis(trialkoxysilyl) telechelic polyether/polyolefin copolymers were synthesized and evaluated as monocomponent adhesive precursors. The Ru-catalyzed tandem ring-opening insertion-metathesis polymerization (ROIMP) and cross-metathesis (CM) reactions in the presence of a bis(trialkoxysilyl)alkene as chain-transfer agent (CTA) were first explored toward the synthesis of such silyl-modified polymers (SMPs). The one-pot, two-step ROIMP/CM of cyclooctene (COE) and poly(propyleneglycol) diacrylate (PPG(*)) with {(EtO)3Si(CH2)3NHC(O)OCH2CH═}2 (CTAEt) catalyzed by Grubb’s second generation catalyst (Method II) successfully enables the preparation of α,ω-[(EtO)3Si]2-PCOE/PPG(*) alternated copolymers, isolated in 10–100 g. The polyether/polyolefin copolymers were thoroughly characterized by SEC, 1D and 2D NMR, and FTIR spectroscopies and mass spectrometry analyses. The good thermal stability and rheofluidifying profile of the PCOE/PPG* copolymers are maintained following their catalyzed moisture-curing, as revealed by TGA, DSC, and rheology. The corresponding siloxane cross-linked copolymers then demonstrate strain-at-break, elongation-at-break, and wood-adhesion properties greater than those of the benchmarked SMP reference from Bostik, namely, Polyvest E100 (strain-at-break on wood up to 4.0 vs 2.6 MPa, respectively). These characteristics can be tuned according to the PCOE/PPG* ratio and also revealed significantly better than the ones of our previously reported alike siloxane cross-linked PCOE/PPG* copolymers similarly prepared, yet from a one-pot, one-step ROIMP/CM approach (Method I). Such polyolefin/polyether monocomponent SMPs are thus promising adhesive precursors.

International audience; The influences of selected catalysts on the structures and properties of polyurethane prepolymers and networks are investigated to adjust the catalyst/structure/properties relationship to a targeted application. This study highlights the necessity of catalysis for polyurethane synthesis, both at the prepolymer and at the crosslinking stages, and emphasizes on the catalyst-dependency of each stage. We also suggest some tin-free and overall metal-free alternatives to ubiquitous tinbased catalysts with metals such as Bi, Ti, Zn and organic catalysts such as DABCO, DMDEE. In polyurethane formulations without fillers, the strong interwoven urethane-and urea-devired H-bonding network is mainly responsible for the mechanical properties of the material and tends to overshadow the catalyst effects. Nonetheless, in presence of fillers such as those used in industrial polyurethane formulations, tensile test evidenced that mechanical properties are affected and can be tailored by the choice of catalyst.

Despite their instability, carbon-centered radicals have been involved as intermediates in many organic transformations that are essential to mankind. Radical polymerization,1-5 for example, provides a large part of polyacrylates and polystyrenes used as commodities in our everyday life. On a molecular level, the outcome of radical-mediated reactions is usually very different from those obtained via classical ionic based organic reactions. This is known since the 1930’s6 and has witnessed extensive developments such as radical cyclization or Atom Transfer Radical Additions (ATRA)7-9 . Radical processes10 typically begin with an initiation step in which the first radical species is created. It is eventually followed by one or several transfer steps which ultimately conduct to the formation of the main radical intermediate responsible for the reaction. The propagation steps of the radical chain are a succession of radical based transformations which, combined, outline the expected transformation.

The first functional cross-metathesis (CM) depolymerization of commercial (co)polydienes using a ruthenium catalyst and an acyclic bis(trialkoxysilyl) difunctionalized chain-transfer agent (CTA), [(EtO) 3 Si(CH 2 ) 3 NHC(O)OCH 2 CH ] 2 ( 1 ), towards the synthesis of low viscosity liquid α,ω-bis(trialkoxysilyl) telechelic (co)polydienes is reported. The reactivity of three commercial grades of liquid (co)polydienes ( P1 – P3 , polybutadienes (PBDs) or poly(butadiene- co -isoprene) (P(BD- co -IP))) differing in their end-functionalization, in the amount of 1,2-vinyl and in their dispersity, was explored. Operating conditions for effective production of α,ω-bis(trialkoxysilyl) telechelic PBDs or P(BD- co -IP)s with high chemoselectivity (80–90 wt%) and catalytic productivity (non-optimized TON up to 24 000) were established. The chemoselectivity of this tandem metathesis reaction was assessed in particular through detailed 2D NMR analyses. An original approach combining the CM depolymerization of PBD with the ring-opening functional metathesis polymerization (ROMP) of a cycloolefin in the presence of CTA 1 has also been next implemented affording low viscosity liquid α,ω-bis(trialkoxysilyl) telechelic copolydienes. The viscosity of the (co)polyolefins was investigated by rheological analyses.

International audience; Current polyurethane (PU) industrial and academic research aims at developing non-isocyanate PUs, referred to as NIPUs. Within this context, we report herein the synthesis of original vinylene carbonate (VC) compounds, subsequently used as chain-transfer agents (CTAs) towards the preparation of α,ω-di(VC) telechelic (co)polyolefins from the tandem ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) of cyclic olefins. Thus, (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl acrylate (VC1), bis((5-methyl-2-oxo-1,3-dioxol-4-yl)methyl) fumarate (VC2), and bis((5-methyl-2-oxo-1,3-dioxol-4-yl)methyl) (E)-hex-3-enedioate (VC3) were synthesized from 4-(hydroxymethyl)-5-methyl-1,3-dioxol-2-one (DMDO-OH). Among these, only VC3 successfully and selectively afforded well-defined α,ω-di(vinylene carbonate) telechelic polyolefins, namely di(VC3)-PCOE and di(VC3)-P(NB-co-CDT), from the ROMP/CM of COE, and norbonene (NB)/trans,trans,cis-1,5,9-cyclododecatriene (CDT), respectively, using Grubbs’ 2nd-generation ruthenium catalyst (G2) under mild operating conditions (CH2Cl2, 40 °C, 3 h). Preliminary investigations on the reactivity of a model VC, namely 4,5-dimethyl-1,3-dioxol-2-one (DMDO), towards nucleophiles such as a primary or secondary amine, promisingly showed the formation of hydroxy-oxazolidone compounds 1 and 2, and oxo-urethane 3 species, respectively. Yet, the ultimate reaction of di(VC3)-PCOE with 2,2′-(ethylenedioxy)bis(ethylamine) (EDR-148) did not give the expected poly(di(hydroxy-oxazolidone)polyolefin) polyaddition type of NIPUs; competing amidation and/or dehydration or urea formation reactions evidenced by detailed NMR, FTIR and MS analyses, were proposed to account for this inefficiency.

Monocomponent alkoxysilyl telechelic rigid polyolefins incorporating soft polyether segments along the backbone are valuable adhesives precursors. Herein, the synthesis of α,ω-bis(trialkoxysilyl) t...

Polyepoxyurethane polymers were synthesized from PolyHydroxyUrethane (PHU) prepolymers terminated amine and epoxy multifunctional. In order to ensure this, PHU prepolymers was synthesized from the reaction between α, ω-bis-cyclic-carbonates (poly(propylene)oxide bis-carbonates) and different excess of diamines (ethylenediamine) to terminate these prepolymers by amine with differents chain length. Then, these aminotelechelic PHU oligomers were re-used in formulation with multifunctional epoxy compound (Bisphenol A Diglycidyl Ether, Di-epoxydized Cardanol or Phloroglucinol Tris Epoxy) to synthesize polyepoxyurethane polymers called also hybrid polymers. Firstly, the raw materials were analyzed in order to determine proportion stoichiometry for carbonate/amine and of hybrid materials formulations. Secondly, for the purpose to demonstrate that the reaction carbonate/amine form hydroxyurethane compound, a model study was realized. Then, syntheses and analyzes of prepolymers terminated amine by 1H, 13C NMR, TGA and DSC was conducted. Once these oligomers analyzed, the hybrid polymers were formulated from epoxy compounds at different temperatures to determine the best cross-linking proceed. Epoxyurethane polymers were characterized by ATG, DSC and measurement of their swelling index and gel content. These materials exhibited glass transition temperature between −5 °C and 42 °C and a thermal stability above 320 °C at 30% of weight loss.

International audience; In this work, a high-throughput screening (HTS) method was used to discover new efficient catalysts to substitute organotin compounds (DBTDL) for the cross-linking of silyl-modified polymers (SMPs). We report here on the use of our HTS method to investigate a library of alkoxide/oxime systems with different metal/ligand (M/L) ratios. Among the 156 candidates tested, 40 interesting hits were detected. Then, the cross-linking times for the better hits were measured on the SMP. Some of these seem to be more efficient than DBTDL and exhibit a good stability during storage in cartridges. Thereby, a high efficiency of alkoxide/oxime systems was established that shows great potential for the generation of new ligands to provide new tin-free catalysts for the cross-linking of adhesives and sealants.

Commercially available poly(propylene glycol) (PPG) and poly(tetrahydrofuran diglycidyl ether) (PTG) α,ω-end-capped with epoxide functions have been chemically modified into α,ω-bis(cyclodithiocarb...

Epoxide- and oxetane-&alpha, &omega, telechelic (co)polyolefins have been successfully synthesized by the tandem ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) of cyclic olefins using Grubbs&rsquo, second-generation catalyst (G2) in the presence of a bifunctional symmetric alkene epoxide- or oxetane-functionalized chain-transfer agent (CTA). From cyclooctene (COE), trans,trans,cis-1,5,9-cyclododecatriene (CDT), norbornene (NB), and methyl 5-norbornene-2-carboxylate (NBCOOMe), with bis(oxiran-2-ylmethyl) maleate (CTA 1), bis(oxetane-2-ylmethyl) maleate (CTA 2), or bis(oxetane-2-ylmethyl) (E)-hex-3-enedioate (CTA 3), well-defined &alpha, di(epoxide or oxetane) telechelic PCOEs, P(COE-co-NB or -NBCOOMe)s, and P(NB-co-CDT)s were isolated under mild operating conditions (40 or 60 &deg, C, 24 h). The oxetane CTA 3 and the epoxide CTA 1 were revealed to be significantly more efficient in the CM step than CTA 2, which apparently inhibits the reaction. Quantitative dithiocarbonatation (CS2/LiBr, 40 &deg, C, THF) of an &alpha, di(epoxide) telechelic P(NB-co-CDT) afforded a convenient approach to the analogous &alpha, bis(dithiocarbonate) telechelic P(NB-co-CDT). The nature of the end-capping function of the epoxide/oxetane/dithiocarbonate telechelic P(NB-co-CDT)s did not impact their thermal signature, as measured by DSC. These copolymers also displayed a low viscosity liquid-like behavior and a shear thinning rheological behavior.

Cross-linking of silyl-modified polymers occurs at the alkoxysilane groups attached to the ends of polymer chains by hydrolysis and polycondensation mechanisms in the presence of moisture. During these reactions, three different physical states can be identified (viscous, skin effect and cross-linked state). Knowledge of the evolution of these states at each reaction time is essential to determine the open time for the adhe-sive industry and is generally obtained by a manual method. Automation of this moni-toring could avoid operator error and could be used for very long cross linking reac-tions or to screen a large number of catalysts. Thus, a contactless micro process tech-nology was developed to correlate these physical states with an optical technology, Raman spectroscopy, by monitoring the decrease in intensity of the Si-OCH3 groups during chemical reactions. This online characterization method can also be used to compare the efficiencies of several catalysts for the cross-linking of silyl-modified polymers, using a minimum amount of chemical materials.

International audience; Expanding on our strategy to design telechelic polyolefins through the catalyzed ring-opening metathesis polymerization/cross metathesis/ring-closing metathesis polymerization of cyclic olefins using bifunctional symmetric alkene chain transfer agents (CTAs), we have now explored the metathesis of cyclooctene (COE), 1,5,9-cyclododecatriene (CDT), and norbornene (NB), using azlactone (AZL)-functional CTAs, toward the synthesis of original AZL telechelic polyolefins. The monofunctional 2-vinyl-4,4-dimethylazlactone predominantly gives, as anticipated, (isomerized) monofunctional and/or difunctional PCOEs. On the other hand, the new symmetric AZL-based CTAs 1–3, namely, (E)-2,2′-(ethene-1,2-diyl)bis(4,4-dimethyloxazol-5(4H)-one) (1), (E)-2,2′-(but-2-ene-1,4-diyl)bis(4,4-dimethyloxazol-5(4H)-one) (2), and (E)-2,2′-(but-2-ene-1,4-diyl)bis(3-oxa-1-azaspiro[4.5]dec-1-en-4-one) (3), selectively give α,ω-di(AZL) telechelic PCOEs, along with minor amounts of cyclic PCOE. The synthesis of related AZL telechelic CDT and NB copolymers has also been implemented through such a tandem metathesis approach. Subsequently, the inherent AZL reactivity toward (di)amines has been evidenced using a triethylene glycol diamine, in first the model reaction with CTA 3 and next upon reacting with the new α,ω-di(CTA 3)-P(NB-co-CDT) copolymers, thereby enabling the preparation of original polyolefins/polyamides

This study describes the synthesis and polymerization of a dicyclocarbonate Diels–Alder (DA) adduct to give a thermoresponsive non-isocyanate polyurethane (NIPU). Firstly a model adduct was synthesized by DA reaction between N-methylmaleimide and furfuryl cyclocarbonate ether (FCE). This adduct was characterized by 1H-NMR and its thermal behavior was studied by 1H-NMR, and differential scanning calorimetry (DSC). Then a telechelic dicyclocarbonate DA adduct was obtained by DA reaction between a bismaleimide oligomer and FCE in bulk with full conversion. Its thermal behavior was studied by thermogravimetric analysis (TGA) and DSC. The dicyclocarbonate adduct was polymerized by step-growth polymerization with a diamine, Jeffamine EDR148. The polymerization was performed at room temperature (in order to avoid adduct deprotection) with triazabicyclodecene as the catalyst. The obtained polymer was characterized by size exclusion chromatography (SEC) and 1H-NMR. The polymer thermal behavior was fully characterized by three complementary analyses. By DSC, retro-Diels–Alder temperatures could be measured to be 90–120 °C. By a 1H-NMR kinetic study at 100 °C, it could be shown that after 120 min at 100 °C, 85% of the adducts are deprotected. Finally, by SEC, it was demonstrated that the obtained NIPU polymer chains undergo thermal scission by rDA reaction.

International audience; The synthesis of low viscosity liquid α,ω-bis(trialkoxysilyl) telechelic copolyolefins (DF) via ring-opening metathesis polymerization (ROMP)/cross metathesis (CM) is reported. Copolymerization of a norbornene-based olefin (NB-OLF = norbornene (NB), ethylidene norbornene (ENB), methyl 5-norbornene-2-carboxylate (NBCOOMe), methyl 5-oxanorbornene-2-carboxylate (oxaNBCOOMe), or dicyclopentadiene (DCPD)) with a monocycloolefin (mOLF = cyclooctene (COE), 1,5-cyclooctadiene (COD), or 1,5,9-cyclododecatriene (CDT)) was carried out at 40 °C (except for DCPD at 23 °C) in CH2Cl2 for 24 h, using Grubbs' 2nd generation catalyst (G2) and the bis(trialkoxysilyl)-functionalized symmetric acyclic alkene (RO)3Si(CH2)3NHC(O)OCH2CHCHCH2OC(O)NH(CH2)3Si(OR)3 (R = Me or Et) as the chain-transfer agent (CTA). The catalytic productivity (turnover numbers, TONs, up to 50 000 mol(comonomers) mol(Ru)-1 and 1250 mol(CTA 1) mol(Ru)-1) and selectivity (>85 wt%; only minor amounts of cyclic non-functionalized copolymers (CNFs) formed) toward the formation of the corresponding DFs were quite high, as evidenced by fractionation experiments and detailed 1D and 2D 1H and 13C NMR spectroscopy and SEC analyses. The thermal and rheological properties of the random copolymers, assessed by DSC and viscosimetric analyses, could be tuned according to the nature and the ratio of the comonomers. At 23 °C, P(NBCOOMe-co-COE) and P(oxaNBCOOMe-co-COE) synthesized from a 50:50 ratio of comonomers displayed the lowest viscosity. Such silyl-modified polyolefins (SMPOs) are thus foreseen in possible industrial applications as one-component adhesives.

This new study is a continuation of our previous work on thermocleavable nonisocyanate polyurethanes (NIPUs), but it is focused on crosslinked networks. Two systems are studied: the first system involves a dicyclocarbonate adduct with a PPO-bicyclocarbonate and a triamine as crosslinker. The second system involves a tetracyclocarbonate DA adduct as crosslinker with the same PPO-bicyclocarbonate and a difunctional amine. Firstly, Diels-Alder adducts are synthesized and characterized. Then they are copolymerized to yield two types of cleavable polymer networks. The thermal behavior of synthesized polymers is fully characterized. Finally, by SEC, it was demonstrated that the obtained NIPU polymer chains are sliced up by rDA reaction. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44408.

A series of poly(hydroxyurethane) (PHU) materials were synthesized by step growth polymerization of cyclic carbonates and diamines. Trimethylolpropane tris-carbonate and various poly(propylene oxide) bis-carbonates were copolymerized with EDR-148 or 1,3-cyclohexanebis(methylamine) (CBMA). Thermal, mechanical and thermo-mechanical properties of PHU materials were characterized by DSC, TGA, durometer, dynamometer and DMA. Moreover, for the first time, we report adhesive properties of PHU synthesized without isocyanate on wood, aluminum and glass supports. All these properties were compared to reference polyurethane materials, synthesized from poly(propylene oxide) triol polymerized with hexamethylenediisocyante (HDI) or 1,3-bis(isocyanatomethyl)cyclohexane (CBMI), in order to compare the materials properties of similar chemical structure. PHUs exhibit outstanding adhesion properties due to the presence of hydroxyl groups hanging off the main polycarbonate chain.

International audience; The ring-opening metathesis polymerization/cross-metathesis (ROMP/CM) of cyclooctene (COE) using bis(trialkoxysilyl)alkenes as chain-transfer agents (CTAs) and Ru catalysts to afford difunctionalized polyolefins is reported. The formation of alpha,omega-bis(trialkoxysilyl) telechelic polycycloolefins (DF) with controlled molar mass values takes place quite selectively (>90 wt%), along with minor amounts of cyclic non-functionalized polymers (CNF), as evidenced by NMR, MALDI-ToF MS, SEC analyses and fractionation experiments. The nature of the CTA and catalyst influenced much the efficiency and selectivity of the reaction. (MeO)(3)SiCH2CH=CHCH2Si(OMe)(3) (2) and (MeO)(3)Si(CH2)(3)NHC(O)OCH2CH=CHCH2OC(O)NH (CH2)(3)Si(OMe)(3) (5) proved to be the most efficient CTAs in terms of reactivity, catalyst productivity and selectivity towards DF. Diurethane CTA 5 is easily prepared, and can also be conveniently generated in situ during the ROMP/CM. Grubbs' 2nd-generation catalyst (G2) and Hoveyda-Grubbs's catalyst (HG2) afforded the best compromise in terms of selectivity and productivity, with turnover numbers of up to 95 000 mol(COE) mol(Ru)(-1) and 5000 mol(CTA) mol(Ru)(-1).

International audience; Organotin compounds particularly dibutyltin dilaurate, are commonly used as catalysts in coatings or adhesive materials to crosslink silyl modified polymers. However, environmental concerns should lead before 2020 to ban organotin compounds due to their high toxicity. Thus new catalysts must be developed. According to the different types of catalytic systems, i.e. acid, basic or metal containing catalysts, a large variety of candidates should be tested. Thus a high-throughput screening (HTS) method could be an interesting tool for the detection of new efficient catalysts to substitute organotin compounds. We report a global HTS method, compatible with organic amino or acid catalysts libraries, as well as with metal-containing libraries

The gold standard of neuromuscular monitoring is mechanomyography (MMG). Phonomyography (PMG) and kinemyography (KMG) are new methods of neuromuscular monitoring. In this study, all three methods were compared to determine neuromuscular blockade at the adductor pollicis muscle.In 14 patients, phonomyography was recorded via a microphone taped to the thenar region. A standard mechanomyographic device was applied to the same thumb, and attached to the force transducer. On the contralateral side, a NMT-Mechanosensor(R) probe was attached to the thumb and forefinger (KMG). After induction of general anaesthesia, the ulnar nerves were stimulated supramaximally using superficial electrodes at the wrists using train-of-four (TOF) stimulation every 12 sec. Onset and recovery indices measured by the three methods after mivacurium 0.2 mg x kg(-1) iv were compared using ANOVA-multiple group comparisons. Agreement between methods was determined using Lin's concordance correlation coefficient.Onset time and peak effect measured via MMG and PMG were similar. Recovery times from neuromuscular blockade (NMB) as measured via the three methods were not different. Agreement between PMG and MMG was excellent for onset and offset of NMB but unsatisfactory for peak effect. Agreement between MMG and KMG was satisfactory for TOF 0.25 and 0.50, and excellent for TOF 0.75 and 0.90 (onset and peak effect not determined for KMG). Agreement between PMG and KMG was satisfactory for TOF 0.25, 0.50 and 0.75, and excellent for TOF 0.90.Mechanomyography, PMG and KMG show satisfactory agreement for determination of recovery of NMB for clinical purposes.

The synthesis and structural characterization of a series of platinum complexes, hearing N-heterocyclic carbenes (NHC) and divinyltetramethylsiloxane (dvtms) as supporting ligands, are described. The reaction of commercially available Karstedt's catalyst (Pt-2{(eta(2) -ViSiMe(2))(2)O}(3)) with in situ generated NHC leads to monomeric platinum(O) complexes in which one NHC is bound to the metal center, as indicated by spectroscopic analysis and single-crystal X-ray diffraction studies. The relative reactivity trend for these complexes as catalysts for the hydrosilylation of alkenes is discussed in terms of NHC ligand steric properties. (c) 2005 Elsevier B.V. All rights reserved.

Using phonomyography, a new monitoring technique of neuromuscular blockade (NMB), we compared NMB after mivacurium 0.1 mg/kg at the lateral cricoarytenoid muscle (LCA) with a possible external monitoring site of the larynx. In 12 patients, data were obtained at both sites using phonomyography. Anesthesia was induced with remifentanil 0.25-0.5 microg . kg(-1) . min(-1) followed by propofol 2-3 mg/kg. A small piezo-electric microphone was positioned beside the vocal cords into the muscular process at the base of the arytenoid cartilage to record acoustic signals from the contraction of the LCA. A second microphone was positioned at an external site, lateral to the trachea, just below the thyroid notch. The recurrent laryngeal nerve was stimulated supramaximally using train-of-four (TOF) stimulation every 12 s. Onset, maximum effect, and offset of NMB were measured and compared. Peak effect, time to reach (T) 25%, 75%, and 90% of control twitch response, and TOF recovery to TOF ratios 0.5-0.8 were significantly longer at the external site. The onset time was not significantly different between the two sites. We used phonomyography with a microphone placed at the neck to evaluate the possibility to externally monitor NMB at the larynx. When compared with LCA, we found a more pronounced peak effect and longer offset of NMB. The acoustic signals recorded at this external site are unlikely to stem from laryngeal muscle contraction but are rather a result of contraction of the strap muscles of the neck.

Phonomyography (PMG) is a novel method to determine neuromuscular blockade (NMB) with high sensitivity and applicability at all muscles. The adductor pollicis muscle has long been used in research and clinical practice as reference for neuromuscular monitoring. The goal of our study was to compare PMG signals (train-of-four [TOF] ratios and T(1)/T(0) values) from both hands of the same patient to investigate the influence of hand dominance on neuromuscular monitoring. In 14 patients, PMG was recorded via small piezoelectric microphones taped over the thenar mass of both hands. After induction of anesthesia, both ulnar nerves were stimulated supramaximally using TOF stimulation every 12 s. Mivacurium 0.2 mg/kg was administered within 5 s. Onset, maximum effect, and offset of NMB were compared between both adductor pollicis muscles. Twelve patients were right-handed and two patients were left-handed. No statistical difference was found between the signals from the dominant or nondominant hand. Correlation was very good (r = 0.95). Agreement was excellent with a bias of -0.57% and limits of agreement of -17.9% to 16.7% (dominant - nondominant hand). This study shows minimal bias, good correlation and no statistical difference when NMB is monitored at both the dominant and nondominant adductor pollicis muscles. Both hands could be used interchangeably to assess NMB at the adductor pollicis muscle.

Readily available N-heterocyclic platinum-carbene complexes 1 are highly efficient catalysts for the regioselective hydrosilylation of alkenes. These novel organometallics tolerate a wide range of functional and protecting groups, can be stored for prolonged periods of time and are particularly active (TON > 10(6)).

UNLABELLED Phonomyography (PMG) is a new method for measuring neuromuscular blockade (NMB) at the larynx. In this study, we used PMG to compare NMB at the posterior cricoarytenoid (PCA) and the lateral cricoarytenoid muscle (LCA) in humans. Twelve patients were included in this study. Endotracheal intubation was performed without aid of neuromuscular blocking drugs. One small condenser microphone was inserted beside the vocal cords into the muscular process at the base of the arytenoid cartilage to record acoustic responses of the LCA (vocal cord adduction), and a second microphone was placed behind the larynx to measure NMB of the PCA (vocal cord abduction). Stimulation of the recurrent laryngeal nerve was performed using superficial electrodes placed at the neck (midline between jugular notch and cricoid cartilage) using train-of-four (TOF) stimulation every 12 s. After supramaximal stimulation, mivacurium 0.1 mg/kg was injected and onset, peak effect, and offset of NMB measured and compared using t-test (P < 0.05). The data are presented as mean (SD). Peak effect, onset time, and early recovery to 25% of control twitch height were not significantly different between PCA and LCA at 86% (13) versus 78% (16), 2.3 min (0.45) versus 2.3 min (1.0), and 9.55 min (3.05) versus 8.5 min (4.7), respectively. However, recovery to 75%, 90% of control twitch height, and recovery to a TOF ratio of 0.8 were significantly longer at the PCA than at the LCA at 14 min (4) versus 11 min (5), 17 min (5) versus 11.8 min (5.6), and 17.5 min (5.6) versus 12.3 min (5.5), respectively. The authors conclude that recovery of NMB at the PCA takes longer than at the LCA in humans after mivacurium. IMPLICATIONS After neuromuscular blockade in humans, the recovery of the ability to open the vocal cords takes longer than the ability to close the vocal cords.

Phonomyography is based on the creation of low frequency sounds during muscle contraction, which can be recorded and used for neuromuscular monitoring. In this study, balloon pressure mechanomyography, a novel method to measure the force of contraction via pressure changes in an air-filled balloon, was compared with phonomyography to determine neuromuscular blockade at the corrugator supercilii muscle.After approval of the Ethics Committee and informed consent, 15 patients were studied. A small condenser microphone was taped to the area just above the eyebrow for phonomyography; an air-filled balloon was taped to the area just above the opposite eyebrow. After induction of anesthesia using remifentanil and propofol, a laryngeal mask airway was inserted without the aid of neuromuscular blocking agents. The facial nerve was stimulated supramaximally with single-twitch stimulation (0.1 Hz) using superficial electrodes placed on both temporal areas for onset and train-of-four stimulation every 12 sec during offset of neuromuscular blockade produced by mivacurium 0.1 mg.kg(-1). Onset and recovery measured by the two methods were compared using the t test and agreement between phonomyography and balloon pressure mechanomyography was examined using the Bland-Altman method.Onset, peak effect, and time to reach 25%, 75%, and 90% of control twitch response for phonomyography vs balloon pressure method were 83 +/- 16 sec vs 81 +/- 15 sec, 80 +/- 15% vs 82 +/- 17%, 7.7 +/- 2.3 min vs 7.5 +/- 2.4 min, 9.9 +/- 4.1 min vs 10.5 +/- 4 min, and 12.6 +/- 4.3 min vs 13.1 +/- 4.5 min respectively without being significantly different. Mean bias was 1% with limits of agreement of -9 and +9% of twitch height (T1).We applied a balloon pressure method to measure the force at the corrugator supercilii. Phonomyography at the corrugator supercilii shows good agreement with this modified version of mechanomyography.

The standard of neuromuscular monitoring is the measurement of the force of contraction (mechanomyography, MMG). Phonomyography (PMG) consists of recording low-frequency sounds created during muscle contraction. In this study, we compared and used both methods to determine neuromuscular blockade (NMB) at the adductor pollicis muscle. In 14 patients, PMG was recorded via a small condenser microphone taped to the thenar mass, and a standard mechanomyographic device was applied to the same arm. In another group of 14 patients, only PMG was measured. After induction of anesthesia, the ulnar nerve was stimulated supramaximally using single twitch stimulation (0.1 Hz) for onset and train-of-four (TOF) stimulation every 12 s during offset of NMB produced by mivacurium 0.1 mg/kg. Onset and recovery indices measured by the 2 methods were compared using Student's t-test (P0.05). Similar comparisons were made between the two PMG groups (with or without special board). Agreement between PMG and MMG was examined using a Bland-Altman test. Onset was 165 (68) s versus 172 (67) s [mean (SD)], and maximum blockade was 89 (10)% versus 90 (11)%, for PMG and MMG respectively (NS). Time to 25%, 75%, and 90% recovery was 16.5 (4.2) min, 22.1 (6.9) min, and 24.5 (8.2) min, respectively for PMG, not different from 16.7 (4) min, 22.8 (8.1) min, and 24.8 (8.8) min for MMG. Mean bias was 0% with limits of agreement of -10 and + 10% of twitch height for all signals (MMG minus PMG). Time to TOF of 0.5, 0.7, 0.8, and 0.9, was 1 min faster with PMG than with MMG, with limits of agreement of -1.5 to 3.5 min. Pharmacodynamic data derived without or with special arm fixation were not significantly different. MMG and PMG can be used interchangeably to determine NMB at the adductor pollicis muscle. PMG is easier to apply, does not need a special monitoring board and could be a reliable monitor to determine NMB in daily routine.Mechanomyography and phonomyography (PMG), a novel method of monitoring neuromuscular blockade (NMB) by recording low-frequency sounds emitted by muscle contraction, can be used interchangeably to determine NMB at the adductor pollicis muscle. PMG is easier to apply, does not need a special monitoring board and could be a reliable monitor to determine NMB in daily routine.

International audience; Ring-opening metathesis polymn./cross-metathesis (ROMP/CM) of cyclooctene (COE) or 3-alkyl-substituted COEs (3R-COEs, R = Et, n-hexyl) using several trialkoxysilyl monofunctionalized alkenes as chain-transfer agents (CTAs; vinyl trimethoxysilane (1), allyl trimethoxysilane (2), and 3-(trimethoxysilyl)propyl acrylate (3)) and various Ru-carbene-alkylidene catalysts afforded several trialkoxysilyl mono- and difunctionalized polyolefins. The formation of α-monofunctional (MF), α,ω-difunctional (DF), isomerized α-monofunctional (IMF), linear nonfunctional (LNF), isomerized linear nonfunctional (ILNF), and cyclic nonfunctional (CNF) PCOEs is rationalized by a two-stage mechanism. First, formation of monofunctionalized (MF) and nonfunctionalized (LNF, CNF) macromols. takes place through a ROMP/CM along with RCM (ring-closing metathesis) process. Subsequently, C=C isomerization (ISOM) combined with a second CM process give isomerized (ILNF, IMF) and difunctionalized (DF) macromols. The nonfunctionalized polymers (CNF, LNF, and ILNF) were formed in minor quantities compared to the trialkoxysilyl-functionalized polymers (MF, IMF, and DF), as evidenced by NMR and MALDI-ToF MS analyses and fractionation expts. The rate and selectivity of the reaction varied with the nature of the CTA, COE substituent, catalyst, and to a lesser extent of the solvent. The use of 1,4-benzoquinone (BZQ) as additive allowed inhibiting completely the ISOM process. Alternatively, steric hindrance in 3-RCOEs substituted monomers resulted in an ISOM-free process with selective formation of MF polymers. The reactive Grubbs' second-generation catalyst (G2) afforded the best compromise in terms of productivity, reactivity, and selectivity. Under optimized conditions favoring the formation of MF/DF, i.e., in CH2Cl2 at 40 °C for 24 h with [COE]0/[CTA 3]0/[G2]0/[BZQ]0 = 2000:20-200:1:100, the polymn. was rather well-controlled. While CTAs 1 and 3 selectively gave mixts. of MF and DF, allyl CTA 2 resulted in a mixt. of IMF, MF, and DF.

The preparation of various potassium organotrifluoroborates bearing either aryl, alkenyl, or alkynyl substituents is described. These stable salts are shown to be very efficient partners in palladium-catalysed cross-coupling reactions with arenediazonium salts, affording biaryl and styrene derivatives in high yields.

The air stable potassium vinyltrifluoroborate 1 was efficiently prepared in one step front vinyhnagnesium chloride and used in palladium cross-coupling reactions with arenediazoniunt salts affording functionalized styrenes.

International audience; α,ω-Di(glycerol carbonate) telechelic poly(propylene glycol) (PPG), poly(ethylene glycol) (PEG), poly(ester ether) (PEE), and poly(butadiene) (PBD) have been synthesized through chemical modification of the corresponding α,ω-dihydroxy telechelic polymers (PPG-OH2, PEG-OH2, PEE-OH2 and PBD-OH2, respectively). Tosylation of the polymer diols with 4-tosylmethyl-1,3-dioxolan-2-one (GC-OTs) afforded, in high yields, the desired PPG, PEG, PEE and PBD end-capped at both termini with a five-membered ring cyclic glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one, GC). The GC-functionalization of the polymers at both chain-ends has been confirmed by NMR (1H, 13C, 1D and 2D) and FTIR spectroscopies. Using PPG-GC2 to demonstrate the concept, the corresponding polyhydroxyurethanes (PHUs/non-isocyanate polyurethanes (NIPUs)) have been subsequently prepared following a non-isocyanate method upon ring-opening catalyst-free polyaddition of the PPG-GC2 with JEFFAMINEs (Mn = 230-2000 g mol−1). The effect of various additives introduced during the polyaddition reaction has been studied at different temperatures. In particular, addition of LiBr (5 mol%) to the reaction medium was found to slightly promote the cyclocarbonate/amine reaction. The polymerization process was supported by FTIR and SEC analyses.

International audience; The ring-opening metathesis polymerization (ROMP) of cyclooctene (COE) has been achieved with Grubbs 2nd generation ruthenium catalyst in the presence of vinyl or acryloyl derivatives of glycerol carbonate. Such asymmetric chain-transfer agents enabled the synthesis in high yields of α-cyclocarbonate,ω-vinyl-poly(cyclooctene) (PCOE) and, more rewardingly, of the highly valuable α,ω-dicyclocarbonate telechelic PCOE.

The air stable potassium vinyltrifluoroborate 1 was efficiently prepared in one step front vinyhnagnesium chloride and used in palladium cross-coupling reactions with arenediazoniunt salts affording functionalized styrenes.

MeO-NAPhePHOS represents the first example of a new series of atropisomeric diphosphines bearing heterotopic biaryl moieties. The key step of its synthesis is the diastereoselective, intramolecular, CuI-promoted coupling of 1-iodonaphthol and 2-iodo-3-methoxyphenol connected by a chiral tether. (R,R)-2,4-Pentanediol is used as the chiral auxiliary in this highly selective reaction that leads to a single enantiomer of the title diphosphine. In the Ru-promoted hydrogenations of carbonyl derivatives, NAPhePHOS affords enantioselectivity levels fully comparable to those of the C2-symmetrical analogues, BINAP and MeO-BIPHEP respectively, thus showing that the lack of C2 symmetry is not detrimental to the catalytic properties of atropisomeric ligands in these hydrogenation reactions.

The vastus medialis muscle has been recently proposed as a new site for monitoring neuromuscular blockade (NMB). The purpose of this study is to compare NMB at the vastus medialis with the adductor pollicis muscle using phonomyography (PMG).Fifteen patients were enrolled in the study. Anesthesia was induced with remifentanil 0.25 to 0.5 microg x kg(-1) x min(-1), followed by propofol 2 to 2.5 mg(-1) x kg(-1) iv. Analgesia was provided by remifentanil 0.05 to 0.25 microg x kg (-1) x min(-1) iv throughout surgery. A small piezo-electric microphone was attached to the middle of the thenar mass of the right hand to record acoustic signals produced by the contraction of the adductor pollicis muscle. A second microphone was fixed to the medial part of the thigh, 10 cm over the patella, to record the response from the vastus medialis muscle. The ulnar nerve and the im branches of the femoral nerve were stimulated using train-of-four stimulation every 12 sec. Onset, maximum effect, and offset of neuromuscular block were measured after mivacurium 0.2 mg x kg(-1) iv and compared.At the vastus medialis muscle, the onset of NMB was significantly shorter at 1.9 +/- 0.6 min vs 2.8 +/- 0.7 min, the maximum effect less pronounced at 85 +/- 11% vs 96 +/- 2% and recovery of NMB to 25%, 75%, 90% of twitch control height more rapid than at the adductor pollicis muscle at 17 +/- 2.2 min vs 21.6 +/- 4.2 min, 26.7 +/- 6.5 vs 21 +/- 4.1 min and 30.7 +/- 6.6 vs 35.9 +/- 7.1 min, respectively.PMG can be used to measure NMB at the vastus medialis muscle. We found a shorter onset time, less pronounced maximum effect and more rapid recovery of NMB at the vastus medialis muscle than at the adductor pollicis muscle.

The new heterotopic atropisomeric diphosphine (R)-5,6-benzo-2,2′-bis(diphenylphosphino)-4′,5′,6′-trimethylbiphenyl has been prepared. The key step of this synthesis is a diastereoselective, intramolecular aryl–aryl coupling reaction via oxidation of a suitable, chiral diarylcuprate. The catalytic properties of the diphosphine in ruthenium promoted hydrogenations of model substrates and in rhodium promoted 1,4-additions of boronic acids to α,β-unsaturated ketones are fully comparable to those of reference ligands such as BINAP. This seems to indicate that C2-symmetry is not a structural prerequisite for atropisomeric chiral diphosphines to obtain high enantioselectivities in 1,4-addition reactions as well as in hydrogenation reactions.

MeO-NAPhePHOS represents the first example of a new series of atropisomeric diphosphines bearing heterotopic biaryl moieties. The key step of its synthesis is the diastereoselective, intramolecular, Cu(I)-promoted coupling of 1-iodonaphthol and 2-iodo-3-methoxyphenol connected by a chiral tether. (R,R)-2,4-Pentanediol is used as the chiral auxiliary in this highly selective reaction that leads to a single enantiomer of the title diphosphine. In the Ru-promoted hydrogenations of carbonyl derivatives, NAPhePHOS affords enantioselectivity levels fully comparable to those of the C(2)-symmetrical analogues, BINAP and MeO-BIPHEP respectively, thus showing that the lack of C(2) symmetry is not detrimental to the catalytic properties of atropisomeric ligands in these hydrogenation reactions.

International audience; The synthesis of a variety of mono- and di-(glycerol carbonate) telechelic polyolefins has been achieved upon ruthenium-catalyzed ring-opening metathesis polymerization (ROMP) of cyclooctene (COE) derivatives in the presence of a vinyl or acryloyl derivative of glycerol carbonate (GC) acting as a chain-transfer agent (CTA). Reaction monitoring based on SEC and 1H NMR analyses suggested that the ROMP proceeds through the formation of first the α-GC,ω-vinyl-poly(cyclooctene) (PCOE) intermediate, which eventually evolves over time into the α,ω-di(GC)-PCOE. The nature of the solvent was shown to have a significant impact on both the reaction rates and the eventual selectivity for the mono-/di-telechelic PCOE. ROMP of 3-alkyl (methyl, ethyl, n-hexyl)-substituted COEs (3-R-COEs) afforded only the α-GC,ω-vinyl-poly(3-R-COE)s, as a result of the steric hindrance around the active intermediate, while a 5-ethyl substituted COE (5-Et-COE) enabled access to the corresponding α,ω-di(GC)-poly(5-Et-COE). The ROMP of 5,6-epoxy-, 5-hydroxy- and 5-oxo-functionalized COEs in the presence of acryloyl-GC as the CTA has also been achieved, affording from the first two monomers polymers with GC end-groups at both extremities, while a 60 : 40 mixture of mono- and di-GC terminated P(5-O[double bond, length as m-dash]COE) was observed in the latter case.