Polysulfonylamine. XLVI Molekülkomplexe von Di(organosulfonyl)aminen mit Dimethylsulfoxid und Triphenylphosphinoxid. Röntgenstrukturanalyse von Di(4-fluorbenzolsulfonyl)amin-Dimethylsulfoxid(2/1)

Polysulfonyl Amines. XLVI. Molecular Adducts of Di(organosulfonyl)amines with Dimethyl Sulfoxide and Triphenylphosphine Oxide. X-Ray Structure Determination of Di(4-fluorobenzenesulfonyl)amine-Dimethyl Sulfoxide(2/1) From equimolar solutions of the respective components in CH₂Cl₂/petroleum ether, the following crystalline addition compounds were obtained: (X? C₆H₄SO₂)₂NH …? OS(CH₃)₂, where X = H, 4? CH₃, 4? Cl, 4? Br, 4? I, 4? NO₂ or 3? NO₂; [(4? F? C₆H₄SO₂)₂NH]₂ · (OS(CH)₃)₂ ( 8 ); (4? I? C₆H₄SO₂)₂NH · OP(C₆H₅)₃. A (2/1) complex of (4? F? C₆H₄SO₂)₂NH with OP(C₆H₅)₃ could not be isolated. The solid-state structure of the (2/1) compound 8 is compared with the known structure of the (1/1) complex (CH₃SO₂)₂NH · OS(CH₃)₂. The crystallographic data for 8 at ?95°C are: monoclinic, space group C2/c, a = 2 369.9(13), b = 1 006.8(4), c = 2 772.6(13) pm, β = 110.71(4)°, U = 6.187 nm³, Z = 8. Two N? H …? O hydrogen bonds with N …? O 275 and 280 pm connect the disulfonylamine molecules with the dimethyl sulfoxide molecule. The O atom of the latter has a trigonal-planar environment consisting of the S atom and the two hydrogen bond H atoms.     

Cross-linking kinetics study and high temperature mechanical properties of ethylene–octene copolymer (EOC)/dicumylperoxide(DCP) system

Ethylene–octene copolymer (EOC) was cross-linked by dicumyl peroxide (DCP) at various temperatures (150–200 °C). Six concentrations of DCP in range 0.2–0.7 wt.% were investigated. Cross-linking was studied by rubber process analyzer (RPA). From RPA data analysis real part modulus s′, tan(delta) and reaction rate constant K were investigated as a function of peroxide content and temperature. The highest s′_max and the lowest tan(delta) were found for 0.7% of DCP at 150 °C. The quantitative analysis confirmed that the DCP–EOC cross-linking was occurring as first order reaction. The highest cross-linking kinetics constant K was found for 0.6% of peroxide at 200 °C. The activation energy of cross-linking E_A obtained by Arrhenius plot had maximum at 0.5–0.6% of peroxide. While at 190–200 °C temperature range there was no detectable degradation for 0.2% of peroxide, for 0.4–0.7% of peroxide there was increasing level of degradation with increasing peroxide content. Generally, at low temperatures (150–180 °C) the increasing peroxide content caused increase in cross-linking kinetics. However at higher temperatures (190–200 °C) increase in kinetics (for 0.2–0.5% of peroxide) was followed by decrease. Especially in 0.6–0.7% peroxide level range the cross-linking is in competition with degradation which lowers the overall cross-linking kinetics. Gel content of the cross-linked EOC samples was found to be increasing with increase in peroxide content, which is caused by the increased cross-link network. Cross-linked samples were subjected to creep studies at elevated temperature (150 °C) and the result was found in agreement with the gel content and RPA results. Storage modulus and tan(delta) values obtained by Dynamic Mechanical Analysis (DMA) also support the RPA results.     

Polysulfonylamine. LVII. Zwei Silber(I)-di(organosulfonyl)-amide mit einer Silber-η2-Aryl- beziehungsweise einer Silber-Silber-Wechselwirkung: Kristallstrukturen von Silberdi(benzolsulfonyl)-amid-Wasser (1/0,5) und von wasserfreiem Silberdi(4-toluolsulfonyl)-amid

Polysulfonyl Amines. LVII. Two Silver(I) Di(organosulfonyl)-amides with Silver-η²-Aryl or Silver-Silver Interactions: Crystal Structures of Silver Di(benzenesulfonyl)amide-Water (1/0.5) and of Anhydrous Silver Di(4-toluenesulfonyl)-amide Crystals of [(PhSO₂)₂NAg(μ-H₂O)AgN(SO₂Ph)₂]_n ( 5 ) and [(4-Me? C₆H₄SO₂)₂NAgAgN(SO₂C₆H₄-4-Me)₂]_n ( 6 ) were obtained from aqueous solutions. The crystallographic data are for 5 (at ?95°C): monoclinic, space group C2/c, a = 2 743.8(5), b = 600.49(12), c = 1 664.5(3) pm, β = 101.143(15)°, V = 2.6908 nm³, Z = 8, D_x = 2.040 Mg m^?3; for 6 (at ?130°C): monoclinic, space group P2₁/n, a = 1 099.8(5), b = 563.7(3), c = 2 487.7(13) pm, β = 99.68(4)°, V = 1.5203 nm³, Z = 4, D_x = 1.888 Mg m^?3. In both crystals, the silver atom has a fivefold coordination. The structure of 5 displays [(RSO₂)₂N? Ag(μ-H₂O)Ag′? N(SO₂R)₂] units with Ag? N 226.9 pm, Ag? O 236.7 pm and Ag? O? Ag′ 95.3°; the water oxygen lies on a crystallographic twofold axis. These units are extended to two fused six-membered rings by intramolecular dative bonds (S)O → Ag′ and S(O)′ → Ag (249.3 pm). One phenyl group from each (PhSO₂)₂N moiety is η²-coordinated with its p-C and one m-C atom to a silver atom of a neighbouring bicyclic unit related by a glide plane to form infinite parallel strands (p-C? Ag 252.2, m-C? Ag 263.9 pm). The strands are interconnected into parallel layers through hydrogen bonds between H₂O and sulfonyl oxygens [O …? O(S) 276.1 pm]. These layers consist of a hydrophilic inner region containing metal ions, N(SO₂)₂ fragments and water molecules, and hydrophobic surfaces formed by phenyl groups. The structure of 6 features centrosymmetric [(RSO₂)₂N? Ag? Ag′? N(SO₂R)₂] units with two intramolecular dative bonds (S)O → Ag′ and (S)O′ → Ag (Ag? Ag′ 295.4, Ag? N 226.0, Ag? O 229.4 pm). These bi-pentacyclic units are associated by translation parallel to y into infinite strands by two dative (S)O → Ag bonds per silver atom (Ag? O 243.2 and 253.3 pm).     

Berberine formate–succinic acid (1/1)

The title compound [systematic name: 9,10‐di­methoxy‐2,3‐methyl­ene­dioxy‐5,6‐di­hydro­dibenzo­[a,g]­quinolizinium form­ate–succinic acid (1/1)], C₂₀H₁₈NO₄⁺·CHO₂⁻·C₄H₆O₄, con­tains centrosymmetric pairs of almost planar berberine cations, and hydrogen‐bonded (C₄H₆O₄⋯HCOO⁻)₂ rings of succinic acid with formate anions, bonded by O—H⋯O hydrogen bonds with O⋯O distances of 2.4886 (15) and 2.5652 (16) Å. Pairs of cations and mol­ecules of succinic acid are connected by non‐conventional weak C—H⋯O hydrogen bonds, with C⋯O distances of 3.082 (2) and 3.178 (2) Å.     

Preparation of Well‐Defined Diblock Copolymers with Short Polypeptide Segments by Polymerization of N‐Carboxy Anhydrides

Summary: The ring‐opening polymerization of N‐carboxy anhydrides (NCA) of γ‐benzyl‐L ‐glutamate and β‐benzyl‐L ‐aspartate was studied in the presence of an ammonium chloride‐functionalized poly(ethylene oxide) macroinitiator, which possibly prevents side reactions such as NCA deprotonation. Although polymerization initiated by such macroinitiators was found to be quite slow, well‐defined conjugates of poly(ethylene oxide)‐block‐poly(γ‐benzyl‐L ‐glutamate) and poly(ethylene oxide)‐block‐poly(β‐benzyl‐L ‐aspartate) with polydispersity indexes as low as 1.05 were prepared. Moreover, the presence of ammonium chloride chain ends significantly prevented end‐group cyclization of poly(γ‐benzyl‐L ‐glutamate) after polymerization.

Gel permeation chromatograms recorded for the diblock copolymers of poly(ethylene oxide)‐block‐poly(γ‐benzyl‐L ‐glutamate) prepared by N‐carboxy anhydride polymerization initiated either by PEO‐NH₂ macroinitiator or PEO‐NHequation/tex2gif-stack-1.gifCl⁻ macroinitiator.     

Simulating the relaxation dynamics of microwave-driven zeolites

We have performed equilibrium and nonequilibrium molecular dynamics simulations to study how microwave (MW)-heated zeolite systems relax to thermal equilibrium. We have simulated the relaxation of both ionic and dipolar phases in FAU-type zeolites, finding biexponential relaxation in all cases studied. Fast-decay times were uniformly below 1 ps, while slow-decay times were found to be as long as 14 ps. Fast-decay times increase with an increase in the initial temperature difference between MW-heated ions/dipoles and the equilibrium system. Slow-decay times were found to be relatively insensitive to the details of the MW-heated nonequilibrium state. Velocity, force, and orientational correlation functions, calculated at equilibrium to explore the natural dynamics of energy transfer, decay well before 1 ps and show little evidence of biexponential decay. In contrast, kinetic energy correlation functions show strong biexponential behavior with slow-decay times as long as 14 ps. We suggest a two-step mechanism involving initial, efficient energy transfer mediated by strongly anharmonic zeolite-guest forces, followed by a slower process mediated by weakly anharmonic couplings among normal modes of the zeolite framework. In addition to elucidating relaxation from MW-heated states, we expect that these studies will shed light on energy transfer in other contexts, such as adsorption and reaction in zeolites, which often involve significant heat release.     

Kinetic Modeling of ICAR ATRP

Kinetic modeling is used to better understand and optimize initiators for continuous activator regeneration atom‐transfer radical polymerization (ICAR ATRP). The polymerization conditions are adjusted as a function of the ATRP catalyst reactivity for two monomers, methyl methacrylate and styrene. In order to prepare a well‐controlled ICAR ATRP process with a low catalyst amount (ppm level), a sufficiently low initial concentration of conventional radical initiator relative to the initial ATRP initiator is required. In some cases, stepwise addition of a conventional radical initiator is needed to reach high conversion. Under such conditions, the equilibrium of the activation/deactivation process for macromolecular species can be established already at low conversion.