In Situ Small‐Angle X‐ray Scattering Investigation of the Formation of Dual‐Mesoporous Materials

The formation of a 2D‐hexagonal (p6m) silica‐based hybrid dual‐mesoporous material is investigated in situ by using synchrotron time‐resolved small‐angle X‐ray scattering (SAXS). The material is synthesized from a mixed micellar solution of a nonionic fluorinated surfactant, R^F₈(EO)₉ (EO=ethylene oxide) and a nonionic triblock copolymer, P123. Both mesoporous networks, with pore dimensions of 3.3 and 8.5 nm respectively, are observed by nitrogen sorption, transmission electron microscopy (TEM), and SAXS. The in situ SAXS experiments reveal that mesophase formation occurs in two steps. First the nucleation and growth of a primary 2D‐hexagonal network (N1), associated with mixed micelles containing P123, then subsequent formation of a second network (N2), associated with micelles of pure R^F₈(EO)₉. The data obtained from SAXS and TEM suggest that the N1 network is used as a nucleation center for the formation of the N2 network, which would result in the formation of a grain with two mesopore sizes. Understanding the mechanism of the formation of such materials is an important step towards the synthesis of more‐complex materials by fine tuning the porosity.     

Phase behavior of methoxypolyoxyethylene dodecanoate as compared to polyoxyethylene dodecyl ether and polyoxyethylene methyl dodecyl ether

The phase behavior of binary systems composed of water and nonionic surfactants were investigated. The nonionic surfactants studied were the methoxypolyoxyethylene dodecanoates (R₁₁COO(EO) _n CH₃,n=4.9, 6.1, 7.3, 9.3, and 12.8, wheren is the average number of oxyethylene units).The phase behaviors of R₁₁COO(EO) _n CH₃ were compared with those of the polyoxyethylene dodecyl ethers (R₁₂O(EO) _p H) and polyoxyethylene methyl dodecyl ethers (R₁₂O(EO) _q CH₃) which have been previously reported. It was found that the R₁₁COO(EO) _n CH₃s have lower cloud points and lower upper limit temperatures for the existence of the mesophase as compared to the other two types. A R₁₁COO(EO)_12.8CH₃/water system had favorable solution properties for practical use, such as a relatively narrow hexagonal liquid crystalline region and a lower melting point than the ordinary alcohol ethoxylate type nonionics.     

Premicellar interaction of PEO–PPO–PEO triblock copolymers with partially hydrophobic alcohols: NMR study

The interactions of three alcohols, namely, 2‐butanol (BuOH), 3‐methyl‐2‐butanol (MeBuOH), and 3,3‐dimethyl‐2‐butanol (Me2BuOH) with propylene oxide octamer (PO8) and the copolymers (EO)₈(PO)₁₃(EO)₈ (L35) and (EO)₁₃(PO)₃₀(EO)₁₃ (L64) in D₂O were studied using ¹³C NMR spectra and relaxations and ¹H PFG NMR diffusion measurements. For L64, it was shown that the temperature at which the PO chain starts to change its conformation under dehydration decreases by 6 K for each additional methyl group in the alcohol molecule (i.e. with increasing its hydrophobicity), and the analogous conformation states are attained at temperatures approximately 10 K lower compared using ketonic analogs of the alcohols under the same conditions. Also, the first signs of L64 aggregation, according to the normalized diffusion coefficients, are at temperatures 7, 10, and 13 K lower for BuOH, MeBuOH, and Me2BuOH, respectively. These effects are much weaker for (PO)₁₃ in L35 or nonexistent for (PO)₈ in PO8, thus showing the role of cooperativity in dehydration and aggregation processes. According to diffusion measurements, the molar fraction of the alcohol hydrogen bonded to L64 increases with its hydrophobicity and, in an apparent conflict with thermodynamics, with increasing temperature at which also higher NOE can be observed. Strong hydrogen bond interaction, which is in cooperation with hydrophobic interaction, does not preclude the exchange between bound and free states of the alcohol, however. Using ¹³C transverse relaxation, its correlation time is shown to be of the order of 10 ms. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis and Structure of the Ordered Modification of Ba6EuF12Cl2

Crystals of ordered Ba₆EuF₁₂Cl₂ were found to form during high temperature flux growth. The structure was refined in the hexagonal space group P 6 to R^F(R ) = 0.024(0.024) for 326 reflections and 46 parameters. Lattice parameters are a = b = 1059.27(8) pm and c = 416.36(2) pm; Z = 1. The structure is isotypic to Ba₇F₁₂Cl₂. No solid solution of Ba/Eu was observed, the Eu²⁺ ions are located in the channels formed by 3 + 6 fluorine ions, occupying only one of the three metal sites of the Ba₇F₁₂Cl₂ structure.     

Silicophosphates of Rhodium and Indium

Single crystals of Rh(Si₂O)(PO₄)₃ and In₄(Si₂O) · (PO₄)₆ were prepared by chemical transport reactions in silica tubes and their structures were determined. Crystal data of Rh(Si₂O)(PO₄)₃: trigonal, space group P 3 c1, a = 8.088(3) Å, c = 8.740(2) Å, Z = 2, R(F²) = 0.0379, R_w(F²) = 0.0518 for 601 unique reflections. In₄(Si₂O)(PO₄)₆: hexagonal, space group P6₃/m, a = 8.5149(10) Å, c = 7.7481(12) Å, Z = 1, R(F²) = 0.0436, R_w(F²) = 0.0522 for 509 unique reflections. Both of the compounds have hexagonal close packed array of phosphate groups with metal atoms and SiOSi units in the octahedral interstices, where the SiOSi units show occupational disorder. The structure of the indium compound is considered to be a disordered structure of the reported Mo₄Si₂P₆O₁₃ structure, and contains confacial bioctahedral units.     

Phase Behavior of Tetradecyldimethylaminoxide in the Presence of Perfluorooctanol and HCl

The ternary phase diagrams of zwitterionic single-chain hydrocarbon surfactant (tetradecyldimethylaminoxide, C₁₄DMAO)—a perfluoro cosurfactant (1,1-H-dihydroperfluorooctanol, C₇F₁₅CH₂OH)-H₂O, and C₁₄DMAO-C₇F₁₅CH₂OH-H₂O-HCl have been studied at 25°C. The identification of the phases was done by means of electrical conductivity, optical polarizing microscopy, and ²H-NMR techniques. In this system the originally uncharged zwitterionic surfactant was increasingly charged by protonation through addition of HCl. The sequence of the phases observed is similar to that observed for hydrocarbon surfactant–cosurfactant mixtures, namely, L₁, L₁/L_α, L_α and L₂, as relative volume fraction of apolar compound increases over that of polar compound. The absence of sponge phase (L₃) is a result of the high bending constant of the mixed bilayers in this perfluoro system.     

The Simplest Amino‐borane H2B=NH2 Trapped on a Rhodium Dimer: Pre‐Catalysts for Amine–Borane Dehydropolymerization

The μ‐amino–borane complexes [Rh₂(L^R)₂(μ‐H)(μ‐H₂B=NHR′)][BAr^F₄] (L^R=R₂P(CH₂)₃PR₂; R=Ph, ⁱPr; R′=H, Me) form by addition of H₃B?NMeR′H₂ to [Rh(L^R)(η⁶‐C₆H₅F)][BAr^F₄]. DFT calculations demonstrate that the amino–borane interacts with the Rh centers through strong Rh‐H and Rh‐B interactions. Mechanistic investigations show that these dimers can form by a boronium‐mediated route, and are pre‐catalysts for amine‐borane dehydropolymerization, suggesting a possible role for bimetallic motifs in catalysis.     

Low molecular weight aromatic compounds possessing a nonflammable characteristic in fluoroalkyl end‐capped acrylic acid oligomer/silica nanocomposite matrices after calcination at 800 °C under atmospheric conditions

Fluoroalkyl end‐capped acrylic acid oligomer [R_F‐(ACA)_n‐R_F] reacted with tetraethoxysilane and silica nanoparticles in the presence of low molecular weight aromatic compounds [ Ar‐H ] such as cetylpyridinium chloride (CPC) and bisphenol AF under alkaline conditions to afford R_F‐(ACA)_n‐R_F/SiO₂ nanocomposites‐encapsulated Ar‐H in 47–94% isolated yields. These fluorinated silica nanocomposites‐encapsulated Ar‐H can exhibit no weight loss behavior corresponding to the contents of Ar‐H after calcination at 800 °C under atmospheric conditions, although fluoroalkyl end‐capped acrylic acid oligomer in the nanocomposites decomposed completely under similar conditions. UV‐vis spectra of well‐dispersed methanol solutions of R_F‐(ACA)_n‐R_F/SiO₂/CPC nanocomposites before calcination show that CPC can be encapsulated into fluorinated silica nanocomposites with encapsulated ratios: 23–43%. The fluorinated nanocomposites after calcination was found to exhibit a higher antibacterial activity related to the presence of CPC in the composites. Encapsulated bisphenol AF into R_F‐(ACA)_n‐R_F/SiO₂ nanocomposites before and after calcination at 800 °C can exhibit a good releasing ability toward methanol with released ratios: 48 and 26%, respectively. ¹H MAS NMR, HPLC analysis, and LC‐MS spectra of R_F‐(ACA)_n‐R_F/silica nanocomposites‐encapsulated bisphenol AF also showed the presence of bisphenol AF in the nanocomposites even after calcination at 800 °C under atmospheric conditions. These findings suggest that CPC and bisphenol AF can exhibit a nonflammable characteristic in the fluorinated silica nanocomposites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

The Effects of Alcohol with Different Chain Length on the Phase Equilibria of Nonionic Surfactant System

Addition of alcohol with longer chain length (C₆H₁₃OH, C₈H₁₇OH, and C₁₂H₂₁OH) caused a reduction the cloud point of a commercial nonionic surfactant, Tesgitol (T_15-s-9). The formation of lamellar liquid crystal (LLC) was favored so that isotropic liquid (L₁)-LLC two-phase region became wider with increasing temperature at an appropriate weight ratio of surfactant to alcohol. The isotropic liquid phase/liquid two phase transformation was replaced by a two-phase transformation to isotropic liquid/lamellar liquid crystal at the cloud point for the system without alcohol.     

Synthese von Oxovanadium(V)‐halogeno‐Komplexen der tripodalen Sauerstoffliganden LR— = [η5‐(C5H5)Co{PR2(O)}3]—, R = OMe,OEt

Syntheses of Oxovanadium(V) Halide Complexes Stabilized with Tripodal Oxygen Ligands L_R^— = [η⁵‐(C₅H₅)Co{PR₂(O)}₃]^—, R = OMe, OEt The sodium salts of the tripodal oxygen ligands L_R^— = [η⁵‐(C₅H₅)Co{PR₂(O)}₃]^— (R = OMe, OEt) react with the oxovanadium halides V(O)F₃ and V(O)Cl₃ to yield deep red compounds of the type [V(O)X₂L_R]. Halide exchange reactions with [V(O)Cl₂L_OMe] und [V(O)F₂L_OMe] aiming at the preparation of the analogous bromide complex [V(O)Br₂L_OMe] led to the isomer [VO(L_OMe)₂][V(O)Br₄]. The crystal structure of [V(O)Cl₂L_OMe] has been determined by single crystal x‐ray diffraction. The compound crystallizes in the monoclinic space group P2₁/n with a = 9.6332(8), b = 15.0312(11) and c = 15.3742(12)Å, β = 100.181(8)°. The coordination around vanadium is distorted octahedral.     

Magnetic Relaxation Probing of the State of Diheptyl Dithiophosphate Ions in Water and Aqueous Triton X-100 Solutions

The nuclear magnetic relaxation was used to study the state of diheptyl dithiophosphoric acid (D7DTP, L₇) anions in water and aqueous solutions of the nonionic surfactant, Ttiton X-100, at 298 K in the presence of paramagnetic probes, Mn²⁺ions. It was found that increase in the spin-lattice relaxation rate of water protons is caused by formation of simple and mixed (with surfactant) aggregates of D7DTP. Unlike the Mn²⁺–sodium dodecyl sulfate –Triton X-100 system, studied previously an influence of a probe concentration was found at surfactant concentration close to the CMC. It was suggested that two types of mixed species containing diheptyl dithiophosphate ions, Mn(II), and nonionic surfactant can be formed: micellar aggregates, {Mn(L₇)₂(TX)}, and polynuclear associates, [Mn _x (L₇) _y (tx) _z ]. The associates likely contain surfactant in the form of monomers (tx).     

Synthesis and reactions of phenyliodonium bis(perfluoroalkanesulfonyl) methides

Phenyliodonium bis(perfluoroalkanesulfonyl) methides PhI⁺ ⁻C(SO₂R_F)₂ ( 3 ) were prepared by the reaction of bis(perfluoroalkanesulfonyl)methanes with diacetoxyiodobenzene. The photochemical reactions of 3 with alkenes, methanol, bromine, and benzene gave the corresponding addition or insertion products. When 3 was irradiated in the presence of methyl sulfide, pyridine, and triphenylphosphine, it afforded the ylides containing the bis(perfluoroalkanesulfonyl)methylene functionality, Y⁺ ⁻C(SO₂R_F)₂. In these reactions the bis(perfluoroalkanesulfonyl)carbene intermediate (R_FSO₂)₂C: may be involved. Irradiation or heating of 3 in DMSO gave a 1 : 1 complex, the structure of which was confirmed by X-ray diffraction analysis. Bis(perfluoroalkanesulfonyl)-methylene dimethyloxosulfonium ylides Me₂(O)S⁺ ⁻C(SO₂R_F)₂ were obtained by air oxidation of bis(perfluoroalkanesulfonyl)methylene dimethylsulfonium ylides.     

Cluster-assisted decomposition reactions of the molecular anions of SF6 and C7F14

The cluster ions formed by the attachment of dimethylsulfoxide (DMSO) and methanol to the molecular negative ions of C₇F₁₄ and SF₆ have been studied by a pulsed e-beam high pressure mass spectrometer (PHPMS) and by an atmospheric pressure ionization mass spectrometer (APIMS). The free energy change (ΔG°) for the clustering equilibria reaction, M⁻ + S M⁻S, at 35 °C are found to be −7.7 and −7.s kcal/mol for S = DMSO and M⁻ = C₇F⁻₁₄ and SF⁻₆, respectively, and −6.4 and −4.5 kcal/mol for S = methanol and M⁻ = C₇F⁻₁₄ and SF⁻₆, respectively. While the cluster ions formed by DMSO are found to be stable against side reactions, those formed by methanol undergo decomposition processes in which the central core ion is fragmented. At 35 °C, the rate law for the decomposition of the SF⁻₆ (CH₃OH)₁ ion is second-order, involving the M⁻ (CH₃OH)₁ cluster ion and another methanol molecule. While the C₇F⁻₁₄(CH₃OH)₁ ion also decomposes through this second-order process, a competing unimolecular mechanism is also operative at 35 °C. With increases in the PHPMS ion source temperature to 150 °C, the unimolecular decomposition process becomes progressively dominant for both of the M⁻(CH₃OH)₁ cluster ions of C₇F₁₄ and SF₆. Methanol cluster ions of the type M⁻S₂ are not observed under any of the conditions examined here. When methanol or water partial pressures of a few torr or higher are present in the buffer gas of the APIMS ion source, the decomposition reactions are very fast and only the fragment ions produced by these reactions are observed in the electron-capture (EC)-APIMS spectra of C₇F₁₄ and SF₆. Also, in the methanol-containing APIMS ion source, the course of the SF⁻₆ decomposition reaction is altered so that fragment ions of the type F⁻(S)_n dominate the EC-APIMS spectrum of SF₆ at all ion source temperatures. For C₇F₁₄, fragment ions of the type F⁻(S)_n become dominant at lower ion source temperatures. These previously unknown reactions are expected to be important in the analysis of perfluorinated compounds by mass spectrometric methods that utilize ionization by electron capture or negative chemical ionization. The nature of the fragment ions produced in these cluster-assisted reactions may also provide a new source of information concerning the structures of the molecular negative ions of SF₆ and C₇F₁₄.     

Highly Active,Thermally Stable,Ethylene‐Polymerisation Pre‐Catalysts Based on Niobium/Tantalum?Imine Systems

The reactions of MCl₅ or MOCl₃ with imidazole‐based pro‐ligand L¹H, 3,5‐tBu₂‐2‐OH‐C₆H₂‐(4,5‐Ph₂‐1H‐)imidazole, or oxazole‐based ligand L²H, 3,5‐tBu₂‐2‐OH‐C₆H₂(1H‐phenanthro[9,10‐d])oxazole, following work‐up, afforded octahedral complexes [MX(L^{1, 2})], where MX=NbCl₄ (L¹, 1 a ; L², 2 a ), [NbOCl₂(NCMe)] (L¹, 1 b ; L², 2 b ), TaCl₄ (L¹, 1 c ; L², 2 c ), or [TaOCl₂(NCMe)] (L¹, 1 d ). The treatment of α‐diimine ligand L³, (2,6‐iPr₂C₆H₃N?CH)₂, with [MCl₄(thf)₂] (M=Nb, Ta) afforded [MCl₄(L³)] (M=Nb, 3 a ; Ta, 3 b ). The reaction of [MCl₃(dme)] (dme=1,2‐dimethoxyethane; M=Nb, Ta) with bis(imino)pyridine ligand L⁴, 2,6‐[2,6‐iPr₂C₆H₃N?(Me)C]₂C₅H₃N, afforded known complexes of the type [MCl₃(L⁴)] (M=Nb, 4 a ; Ta, 4 b ), whereas the reaction of 2‐acetyl‐6‐iminopyridine ligand L⁵, 2‐[2,6‐iPr₂C₆H₃N?(Me)C]‐6‐Ac‐C₅H₃N, with the niobium precursor afforded the coupled product [({2‐Ac‐6‐(2,6‐iPr₂C₆H₃N?(Me)C)C₅H₃N}NbOCl₂)₂] ( 5 ). The reaction of MCl₅ with Schiff‐base pro‐ligands L⁶H–L¹⁰H, 3,5‐(R¹)₂‐2‐OH‐C₆H₂CH?N(2‐OR²‐C₆H₄), (L⁶H: R¹=tBu, R²=Ph; L⁷H: R¹=tBu, R²=Me; L⁸H: R¹=Cl, R²=Ph; L⁹H: R¹=Cl, R²=Me; L¹⁰H: R¹=Cl, R²=CF₃) afforded [MCl₄(L^6–10)] complexes (M=Nb, 6 a – 10 a ; M=Ta, 6 b – 9 b ). In the case of compound 8 b , the corresponding zwitterion was also synthesised, namely [Ta^?Cl₅(L⁸H)⁺] ? MeCN ( 8 c ). Unexpectedly, the reaction of L⁷H with TaCl₅ at reflux in toluene led to the removal of the methyl group and the formation of trichloride 7 c [TaCl₃(L^7‐Me)]; conducting the reaction at room temperature led to the formation of the expected methoxy compound ( 7 b ). Upon activation with methylaluminoxane (MAO), these complexes displayed poor activities for the homogeneous polymerisation of ethylene. However, the use of chloroalkylaluminium reagents, such as dimethylaluminium chloride (DMAC) and methylaluminium dichloride (MADC), as co‐catalysts in the presence of the reactivator ethyl trichloroacetate (ETA) generated thermally stable catalysts with, in the case of niobium, catalytic activities that were two orders of magnitude higher than those previously observed. The effects of steric hindrance and electronic configuration on the polymerisation activity of these tantalum and niobium pre‐catalysts were investigated. Spectroscopic studies (¹H NMR, ¹³C NMR and ¹H? ¹H and ¹H? ¹³C correlations) on the reactions of compounds 4 a / 4 b with either MAO(50) or AlMe₃/[CPh₃]⁺[B(C₆F₅)₄]^? were consistent with the formation of a diamagnetic cation of the form [L⁴AlMe₂]⁺ (MAO(50) is the product of the vacuum distillation of commercial MAO at +50 °C and contains only 1 mol % of Al in the form of free AlMe₃). In the presence of MAO, this cationic aluminium complex was not capable of initiating the ROMP (ring opening metathesis polymerisation) of norbornene, whereas the 4 a / 4 b systems with MAO(50) were active. A parallel pressure reactor (PPR)‐based homogeneous polymerisation screening by using pre‐catalysts 1 b , 1 c , 2 a , 3 a and 6 a , in combination with MAO, revealed only moderate‐to‐good activities for the homo‐polymerisation of ethylene and the co‐polymerisation of ethylene/1‐hexene. The molecular structures are reported for complexes 1 a – 1 c , 2 b , 5 , 6 a , 6 b, 7 a, 8 a and 8 c .     

Aggregation behavior of block polyethers with branched structure at air/water surface

The block polyethers with various branch structure, such as TEPA[(PO)₃₆(EO)₁₀₀]₇, TEPA[(PO)₃₆(EO)₁₀₀(PO)₃₆]₇, and TEPA[(PO)₃₆(EO)₁₀₀(PO)₅₆]₇ were synthesized. Moreover, the aggregation behavior was investigated via the measurements of equilibrium surface tension, dynamic surface tension, and surface dilational viscoelasticity, in order to probe the effect of the block structure on the property of the branched block polyethers. The surface tension results show that the efficiency and effectiveness of the block polyethers to lower surface tension increase with the increase of the PO group numbers. The maximum surface excess concentration (Γ_max) values and the minimum occupied area per molecule at the air/water interface (A_min) values of the branched block polyethers obtained from Gibbs adsorption equations increase and decrease with the increases of the PO group numbers, respectively. The dynamic parameters n and t^* representing the diffusion speed of the polyether molecules from bulky solution to the subsurface and from the subsurface to the air/water surface are obtained according to the equation proposed by Rosen. The results show that the n values firstly increase and then decrease and t^* values decrease with the increase of the polyether concentrations. The results of surface dilational viscoelasticity show that the dilational modulus of TEPA[(PO)₃₆(EO)₁₀₀(PO)₅₆]₇ is the largest among the three block copolymers at the low concentration (<1 mg L⁻¹) but that of TEPA[(PO)₃₆(EO)₁₀₀]₇ is the largest at the high concentration (>1 mg L⁻¹).     

Dioxouranium Complexes with Acetylpyridine Benzoylhydrazones and Related Ligands

Acetylpyridine benzoylhydrazone and related ligands react with common dioxouranium(VI) compounds such as uranyl nitrate or [NBu₄]₂[UO₂Cl₄] to form air‐stable complexes. Reactions with 2, 6‐diacetylpyridinebis(benzoylhydrazone) (H₂L^1a) or 2, 6‐diacetylpyridinebis(salicylhydrazone) (H₂L^1b) give yellow products of the composition [UO₂(L¹)]. The neutral compounds contain doubly deprotonated ligands and possess a distorted pentagonal‐bipyramidal structure. The hydroxo groups of the salicylhydrazonato ligand do not contribute to the complexation of the metal. The equatorial coordination spheres of the complexes can be extended by the addition of a monodentate ligand such as pyridine or DMSO. The uranium atoms in the resulting deep‐red complexes have hexagonal‐bipyramidal coordination environments with the oxo ligands in axial positions. The sterical strains inside the hexagonal plane can be reduced when two tridentate benzoylhydrazonato ligands are used instead of the pentadentate 2, 6‐diacetylpyridine derivatives. Acetylpyridine benzoylhydrazone (HL²) and bis(2‐pyridyl)ketone benzoylhydrazone (HL³) deprotonate and form neutral, red [UO₂(L)₂] complexes. The equatorial coordination spheres of these complexes are puckered hexagons. X‐ray diffraction studies on [UO₂(L^1a)(pyridine)], [UO₂(L^1b)(DMSO)], [UO₂(L²)₂] and [UO₂(L³)₂] show relatively short U—O bonds to the benzoylic oxygen atoms between 2.328(6) and 2.389(8) Å. This suggests a preference of these donor sites of the ligands over their imino and amine functionalities (U—N bond lengths: 2.588(7)—2.701(6) Å ).     

Fluoroalkyl Radical Generation by Homolytic Bond Dissociation in Pentacarbonylmanganese Derivatives

Thermal decarbonylation of the acyl compounds [Mn(CO)₅(COR_F)] (R_F=CF₃, CHF₂, CH₂CF₃, CF₂CH₃) yielded the corresponding alkyl derivatives [Mn(CO)₅(R_F)], some of which have not been previously reported. The compounds were fully characterized by analytical and spectroscopic methods and by several single-crystal X-ray diffraction studies. The solution-phase IR characterization in the CO stretching region, with the assistance of DFT calculations, has allowed the assignment of several weak bands to vibrations of the [Mn(¹²CO)₄(eq-¹³CO)(R_F)] and [Mn(¹²CO)₄(ax-¹³CO)(R_F)] isotopomers and a ranking of the R_F donor power in the order CF₃<CHF₂<CH₂CF₃≈CF₂CH₃. The homolytic Mn−R_F bond cleavage in [Mn(CO)₅(R_F)] at various temperatures under saturation conditions with trapping of the generated R_F radicals by excess tris(trimethylsilyl)silane yielded activation parameters ΔH^≠ and ΔS^≠ that are believed to represent close estimates of the homolytic bond dissociation thermodynamic parameters. These values are in close agreement with those calculated in a recent DFT study (J. Organomet. Chem. 2018 , 864, 12–18). The ability of these complexes to undergo homolytic Mn−R_F bond cleavage was further demonstrated by the observation that [Mn(CO)₅(CF₃)] (the compound with the strongest Mn−R_F bond) initiated the radical polymerization of vinylidene fluoride (CH₂=CF₂) to produce poly(vinylidene fluoride) in good yields by either thermal (100 °C) or photochemical (UV or visible light) activation.     

Coordination Chemistry of Sulfonyl Amides. 2 The Crystal Structure of Copper(II) and Silver(I) Complexes of N,N-4-Toluenesulfonyl-2-Pyridylaminato Ligand

Three structures containing the N,N-4-toluenesulfonyl-2-pyridylaminato ligand are presented. The brown crystal of Cu₂L₄ (L =N,N-4-toluenesulfonyl-2-pyridylaminato) was found to crystallize in the monoclinic space group P2,/c with a = 15.762(12), b = 15.552(5), c = 20.505(11) Å, β = 104.14(7)°; V = 4874(5) Å^3;Z = 4; the final R_F = 0.050, R_WF = 0.049 for 5142 observed reflections and 612 variables. The Cu-Cu distance is small, 2.516(2) Å and the complex is diamagnetic at room temperature. The colorless crystal of Ag₂L was found to crystallize in the monoclinic space group P2_t/n with a = 9.620(2), b = 5.625(2), c ? 23.250(3) Å, Å = 94.72(1)°; V = 1254.0(5) ų; Z = 2; the final R_F = 0.027; R_WF = 0.028 for 1929 observed reflections and 164 variables. The Ag-Ag distance is 2.739(1) Å The green crystal of CuL₂ (py)₂was found to crystallize in the monoclinic space group P2₁ with a = 9.366(2), b = 20.615(7), c = 9.862(2) Å,β = 116.73(2)°; V = 1700.5(8) ų; Z = 2; the final R_F = 0.037; R_WF = 0.038 for 1636 observed reflections and 423 variables. A reversible transformation between Cu₂L₄ and CuL₂(py)₂ is reported.     

Phase equilibria and structures in ternary systems of a cationic surfactant (C16 TABr or (C16 TA)2SO4), alcohol,and water

The dependence of alcohol chain length on the isothermal phase behavior of the ternary systems hexadecylrrimethylammonium bromide/alcohol/water has been investigated. A liquid crystalline phase (the normal hexagonal one) occurs in the phase diagrams along the surfactant/water axis and this phase extends in the interior of the diagrams.When the alcohol is methanol, ethanol or butanol, there is in the ternary phase diagram a continuous solution region from the water to the alcoholic corner, and in the butanol case, in addition, a small region of lamellar liquid crystalline phase in the interior of the diagram. When the alcohol chain length is increased, the continuous solution region is divided into two subregions, an aqueousL ₁ and an alcoholicL ₂. The lamellar phase occupies the center of the phase diagrams and has the capability to incorporate large amounts of water under one-dimensional swelling. On the alcoholic side of the lamellar phase occur a reversed hexagonal liquid crystalline phase and a cubic liquid crystalline phase in the octanolic system; in the decanolic system the cubic phase is missing, but instead another liquid crystalline phase, presumably with rod-structure, occurs in addition to the reversed hexagonal phase.In a decanolic system where the monovalent bromide ion is replaced by the divalent sulphate ion there are the same solution regionsL ₁ andL ₂, and phase regions with liquid crystalline normal hexagonal and lamellar structures. The lamellar phase has lost much of its capability of incorporating water. That is in analogy with the conditions in anionic systems where the counterion charge has been increased. There is no reversed hexagonal phase, but on the alcoholic side of the lamellar phase, there is the same foreign liquid crystalline phase with a presumed rod-structure as in the monovalent system.     

Synthesis and characterization of fluorous (S)- and (R)-1-phenylethylamines that effect heat facilitated resolution of (±)-2-(8-carboxy-1-naphthylsulfinyl)benzoic acid via diastereomeric salt formation and study of their circular dichroism

Perfluoroalkyl- or nonafluoro-tert-butoxy-alkyl-substituted enantiopure amines having the structure PhCHCH₃(NR¹R²) [R¹ = H, CH₃; R² = (CH₂)₃C₈F₁₇, (CH₂)₂OC(CF₃)₃; R¹ = R² = (CH₂)₃C₈F₁₇, (CH₂)₂OC(CF₃)₃] are obtained in high yields, when (S)-(−)-1-phenylethylamine is reacted with readily accessible alkylating reagents or fluorous 2° amines (R¹ = H; R² = (CH₂)₃C₈F₁₇, (CH₂)₂OC(CF₃)₃) are methylated in a Leuckart-Wallach reaction. The solubility patterns of these novel chiral amines and their hydrochlorides are qualitatively described for a broad spectrum of solvents and the fluorous partition coefficients of the free bases are determined by GC. A novel method for the resolution of enantiomers is disclosed here, which involves the use a half-equivalent of the selected resolving agent in solvent water that displays low solubility for the crystalline diastereomeric salt(s) formed even at temperatures near to its boiling point. Compound (S)-(−)-PhCHCH₃[NH(CH₂)₃C₈F₁₇] is found to satisfy all the latter conditions and successfully used for the heat facilitated resolution of the title racemic acid. The circular dichroism (CD) spectra of six novel fluorous (S)-(−)-1-phenylethylamine derivatives are measured in ethanol, trifluoroethanol and hexafluoropropan-2-ol and discussed in detail.