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Crystals of penta(carboxymethyl)diethylenetriamine have been structurally characterized through single‐crystal X‐ray diffraction analysis. X‐ray diffraction analysis reveals that various non‐covalent interactions combine to determine the crystal packing and final solid‐state supramolecular assembling behavior. The title compound exhibited various 2D supramolecular networks generated through O−H⋅⋅⋅O and C−H⋅⋅⋅O interactions. The C−H⋅⋅⋅O interactions are pivotal in building a two‐dimensional framework, whose formation is readily analyzed with zero‐dimensional centrosymmetric dimeric rings as building blocks within the structure. All the intermolecular interactions are quantified through Hirshfeld surface analysis and fingerprint plots. Energy frameworks are constructed to analyze the dominant interaction energy involved in molecular packing strength. Bader's quantum theory of "atoms‐in‐molecules" (QTAIM) has been used to analyze and characterize non‐covalent interactions. The QTAIM analysis validates the existence of hydrogen bonding contacts, and the topological properties of bond critical points (BCPs), such as the electron density ρ(r) and its Laplacian ∇2ρ(r), are presented to correlate with the interaction energy. The topological analysis revealed that all of the interactions are closed‐shell interactions. Finally, the "Non‐covalent Interaction" (NCI) plot index illustrates the solid‐state supramolecular networks. [ABSTRACT FROM AUTHOR]

Ditetrelenes R2E=ER2 (E=Si, Ge, Sn, Pb) substituted by multiple N/P/O/S‐donor groups are extremely rare due to their propensity to disaggregate into their tetrylene monomers R2E. We report the synthesis of the first fully phosphanyl‐substituted digermene {(Mes)2P}2Ge=Ge{P(Mes)2}2 (3, Mes=2,4,6‐Me3C6H2), which adopts a highly unusual structure in the solid state, that is both strongly trans‐bent and highly twisted. Variable‐temperature 31P{1H} NMR spectroscopy suggests that 3 persists in solution, but is subject to a dynamic equilibrium between two conformations, which have different geometries about the Ge=Ge bond (twisted/non‐twisted) due to a difference in the nature of their π‐stacking interactions. Compound 3 undergoes unprecedented, spontaneous decomposition in solution to give a unique GeI cluster {(Mes)2P}4Ge4⋅5 CyMe (7). [ABSTRACT FROM AUTHOR]

Adding to the versatile class of ionic liquids, we report the detailed structure and property analysis of a new class of asymmetrically substituted imidazolium salts, offering interesting thermal characteristics, such as liquid crystalline behavior, polymorphism or glass transitions. A scalable general synthetic procedure for N‐polyaryl‐N'‐alkyl‐functionalized imidazolium salts with para‐substituted linker (L) moieties at the aryl chain, namely [LPhmImHR]+ (L=Br, CN, SMe, CO2Et, OH; m=2, 3; R=C12, PEGn; n=2, 3, 4), was developed. These imidazolium salts were studied by single‐crystal X‐ray diffraction (SC‐XRD), NMR spectroscopy and thermochemical methods (DSC, TGA). Furthermore, these imidazolium salts were used as N‐heterocyclic carbene (NHC) ligand precursors for mononuclear, first‐row transition metal complexes (MnII, FeII, CoII, NiII, ZnII, CuI, AgI, AuI) and for the dinuclear Ti‐supported Fe‐NHC complex [(OPy)2Ti(OPh2ImC12)2(FeI2)] (OPy=pyridin‐2‐ylmethanolate). The complexes were studied concerning their structural and magnetic behavior via multi‐nuclear NMR spectroscopy, SC‐XRD analyses, variable temperature and field‐dependent (VT‐VF) SQUID magnetization methods, X‐band EPR spectroscopy and, where appropriate, zero‐field 57Fe Mössbauer spectroscopy. [ABSTRACT FROM AUTHOR]

FcC(O)CH=C(OH)R (1, R=Me; 2, R=Fc; Fc=Fe(η5‐C5H4)(η5‐C5H5)) reacts with 1‐H2N‐4‐R'‐C6H4 (3 a, R'=Me; 3 b, R'=OMe; 3 c, R'=C≡N; 3 d, R'=F) producing β‐ketoamines FcC(O)CH=C(NH(C6H4‐4‐R'))R (4 a–d, R=Me; 5 a–d, R=Fc). Electrochemistry shows that 4 a–d possess one (4 a: E°′=90 mV; 4 b: E°′=80 mV; 4 c: E°′=145 mV; 4 d: E°′=95 mV) and 5a–d two (5 a: E°′1,2=90, 305 mV; 5 b: E°′1,2=85, 305 mV; 5 c: E°′1,2=155, 360 mV; 5 d: E°′1,2=105, 325 mV) reversible redox processes. In 5 a–d electrostatic interactions occur among Fc/[Fc]+ as oxidation progresses, as evidenced by UV/vis‐NIR spectroscopy. Compounds 4 a,d and 5 b,c display an irreversible N‐oxidation at 1100–1450 mV, while 4 b owns a reversible event at 910 mV. A linear relationship between the σ Hammett constants and the E°′1 values exists. [ABSTRACT FROM AUTHOR]

Solution combustion synthesis followed by annealing in air led to the MPTB‐related phosphates (Rh1/6W5/6O3)8(PO2)4, (Ir1/6W5/6O3)8(PO2)4 (a=5.258(2) Å, b=6.538(3) Å, c=17.322(8) Å), (Rh1/9W8/9O3)12(PO2)4 and (Rh2/21W19/21O3)14(PO2)4. Single‐crystals of the mixed‐metal (Rh,W)‐MPTBs at m=4 and at m=7 were grown by chemical vapor transport (CVT). Their crystal structures have been refined from X‐ray single‐crystal data {(Rh,W)‐MPTB atm=4: P212121, Z=1, a=5.2232(3) Å, b=6.4966(3) Å, c=17.3819(9) Å, R1=0.032, wR2=0.075 for 1714 unique reflections, 1524 with Fo>4σ(Fo), 66 variables, 1 constraint, composition from refinement (Rh0.15W0.85O3)8(PO2)4; (Rh,W)‐MPTB atm=7: P21/n, Z=1, a=5.2510(4) Å, b=6.4949(5) Å, c=26.685(2) Å, β=90.30(1)°, R1=0.060, wR2=0.163 for 2074 unique reflections, 1894 with Fo>4σ(Fo), 100 variables, comp. from ref. (Rh0.07W0.93O3)14(PO2)4}. These structure refinements show unexpected distribution of Rh and W over the available metal sites. Further characterization (powder reflectance and magnetic measurements) of the (Rh,W)‐MPTB at m=4 and at m=7 suggest for both phases a homogeneity range with respect to the Rh/W ratio and the presence of small amounts of W5+ besides Rh3+ and W6+. Results of the ligand field analysis for the reference material Rh(PO3)3, which is containing the octahedral chromophore [RhIIIO6], are reported (Δo=23200 cm−1, B=490 cm−1). [ABSTRACT FROM AUTHOR]

Herein we present the first solid‐state structures of tetraiododiborane(4) (B2I4), which was long believed to exist in all phases as discrete molecules with planar, tricoordinate boron atoms, like the lighter tetrahalodiboranes(4) B2F4, B2Cl4, and B2Br4. Single‐crystal X‐ray diffraction, solid‐state NMR, and IR measurements indicate that B2I4 in fact exists as two different polymeric forms in the solid state, both of which feature boron atoms in tetrahedral environments. DFT calculations are used to simulate the IR spectra of the solution and solid‐state structures, and these are compared with the experimental spectra. [ABSTRACT FROM AUTHOR]

Abstract: The structure of Cs3RESi6O15, where RE=Dy–Lu, Y, In, is unusual in that it contains octahedrally coordinated rare‐earth ions; their relative orientation dictates the structure, as they rotate about the c‐axis supported by the cyclic Si6O15 framework. The repeat unit of the rotation is eight units generating a very long (ca. 57 Å) unit cell axis. This unusual repeat unit is created by the structural flexibility of the hexasilicate ring, which is in turn affected by the size of the rare earth ion as well as the size of alkali ion residing within the silicate layers. Previous work showed for the smaller Sc3+ ion, the rotation of the octahedra is not sufficient to achieve closure at an integral repeat unit and an incommensurate structure results. The products are prepared as large, high quality single crystals using a high‐temperature (650 °C) hydrothermal method with CsOH and F− mineralizers. The presence of fluoride is essential to the formation of the product. [ABSTRACT FROM AUTHOR]

The effect of ethylene content, in a range between 8 and 11 mol%, and distribution on the solid‐state morphology of five impact polypropylene copolymers (IPC) have been studied via SEM, fractionation and microstructural characterization via gel permeation chromatography (GPC), high‐temperature thermal‐gradient interaction chromatography (HT‐TGIC), and differential scanning calorimetry (DSC). All copolymers display heterophasic morphology, with rubbery droplets randomly distributed in a predominant iPP matrix. While the mass fraction of amorphous ethylene‐propylene rubber molecules is very similar for all IPC studied, the size of the droplets increases from 0.6 to 1.1 μm with increasing ethylene content. This change in droplet size is correlated with changes in the composition of the crystalline ethylene‐propylene (CEP) component extracted via fractionation. [ABSTRACT FROM AUTHOR]

We have investigated the ground state properties of buckled GaAs monolayer using density functional theory (DFT) and quantum Monte Carlo (QMC) method. Standard first-principles approaches such as DFT with approximate exchange-correlation functionals do not describe the correlation effect accurately and hence, usually cannot predict results within the chemical accuracy. In order to accurate evaluation of correlation energy that makes a small but very important contribution to the total energy of an electronic system, the quantum Monte Carlo methods are used which include the correlation effect of electron-electron using Jastrow function. We found QMC energies are few tenths eV lower than the DFT energies and the buckled GaAs monolayer have direct the band gap of 1.46 eV within DFT calculations, whereas quasiparticle gap is 3.4(8) eV within QMC calculations. We have also calculated the electron affinity and ionization potential as a function of system size. [ABSTRACT FROM AUTHOR]

In the present work, we have systematically studied structural, electronic and optical properties of buckled GaAs bilayer with and without spin-orbit coupling by density functional theory. Buckled GaAs bilayer have direct band gap of 0.70 eV at high symmetric Г-point which is low as compare to GaAs monolayer. Optical properties such as real and imaginary part of dielectric functions, refractive index, extinction coefficient, absorption spectrum and reflectivity are well studied using density function theory. The calculated optical properties show that the buckled GaAs bilayer can be beneficial for optoelectronic and light emitting devices. [ABSTRACT FROM AUTHOR]

The control of the glass transition temperature ( Tg) of methacrylic acid-styrene terpolymers with n-butyl methacrylate (BMA) is scoped to assess their potential to alter the thermal transitions of boron subphthalocyanine (BsubPc)-containing polymers. The change in kinetics and physical properties of the terpolymers are observed under different synthetic and process conditions such as varying molar feed of BMA, addition of 1,4-dioxane solvent, reaction time, concentration of N-tert-butyl- N-(1-diethylphosphono-2,2-dimethylpropyl) nitroxide (SG1) mediator and initiator type to find the optimal conditions. Four terpolymers are then coupled to BsubPc using the established process. Differential scanning calorimetry analysis shows that the backbone polymer composition has little effect on the Tg of the poly-BsubPcs. Solid-state fluorescence spectroscopy reveals that after annealing the films at temperatures higher than the Tg, BsubPc aggregates are formed and, therefore, the arrangement of the polymers is dominated by the BsubPc moiety and its self-aggregation. [ABSTRACT FROM AUTHOR]

Li18P6N16 was synthesized by reaction of LiPN2 and Li7PN4 at 5.5 GPa and 1273 K employing the multi-anvil technique. It is the first lithium nitridophosphate obtained by high-pressure synthesis. Moreover, it is the first example received by reaction of two ternary lithium nitrides. The combination of high-pressure conditions with a Li3N flux enabled a complete structure determination using single-crystal X-ray diffraction. The hitherto unknown tricyclic [P6N16]18− anion is composed of six vertex-sharing PN4 tetrahedra forming one vierer- and two additional dreier-rings. To confirm the structure, Rietveld refinement, 7Li and 31P solid-state NMR spectroscopy, FTIR spectroscopy and EDX measurements were carried out. To validate the ionic properties, the migration pathways of the Li+ ions were evaluated, and the conductivity and its temperature dependence were determined by impedance spectroscopy measurements. In order to obtain a clearer picture of the formation mechanism of this compound class, different synthetic approaches were compared, enabling targeted syntheses of unprecedented P/N-anion topologies with intriguing properties. [ABSTRACT FROM AUTHOR]

Two planarized analogues of the prototypical Blatter radical ( 1), peri-annulated 1S and 1O, are demonstrated and provide a new platform for molecular and supramolecular engineering, and for tuning electronic and magnetic properties of the radical. Planarization of 1 results in bathochromic shift to the near-IR region, greater spin delocalization, and anodic shift of the reduction potential only for 1S. Magnetization studies revealed nearly ideal paramagnetic behavior at high temperatures for both radicals 1S and 1O with one-dimensional ferromagnetic interaction in the former (2 J=14.4 cm−1) and antiferromagnetic interactions in 1O at low temperatures. [ABSTRACT FROM AUTHOR]

It is shown that UVO2+ ions can reside at UVIO22+ lattice sites during mild reduction and crystallization process under solvothermal conditions, yielding a complicated and rare mixed-valent uranium phosphonate compound that simultaneously contains UIV, UV, and UVI. The presence of uranium with three oxidation states was confirmed by various characterization techniques, including X-ray crystallography, X-ray photoelectron, electron paramagnetic resonance, FTIR, UV/Vis-NIR absorption, and synchrotron radiation X-ray absorption spectroscopy, and magnetism measurements. [ABSTRACT FROM AUTHOR]

It is shown that UVO2+ ions can reside at UVIO22+ lattice sites during mild reduction and crystallization process under solvothermal conditions, yielding a complicated and rare mixed-valent uranium phosphonate compound that simultaneously contains UIV, UV, and UVI. The presence of uranium with three oxidation states was confirmed by various characterization techniques, including X-ray crystallography, X-ray photoelectron, electron paramagnetic resonance, FTIR, UV/Vis-NIR absorption, and synchrotron radiation X-ray absorption spectroscopy, and magnetism measurements. [ABSTRACT FROM AUTHOR]

1,1′-Dinitramino-5,5′-bitetrazole and 1,1′-dinitramino-5,5′-azobitetrazole were synthesized for the first time. The neutral compounds are extremely sensitive and powerful explosives. Selected nitrogen-rich salts were prepared to adjust sensitivity and performance values. The compounds were characterized by low-temperature X-ray diffraction, IR and Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, and DTA/DSC. Calculated energetic performances using the EXPLO5 code based on calculated (CBS-4M) heats of formation and X-ray densities support the high performances of the 1,1′-dinitramino-5,5′-bitetrazoles as energetic materials. The sensitivities toward impact, friction, and electrostatic discharge were also explored. Most of the compounds show sensitivities in the range of primary explosives and should only be handled with great care! [ABSTRACT FROM AUTHOR]

ABSTRACT To obtain novel low-bandgap materials with tailored hole-transport properties and extended absorption, electron rich 3,4-ethylenedioxythiophene is introduced as a comonomer in diketopyrrolo[3,4- c]pyrrole copolymers with different aryl flanking units. The polymers are characterized by absorption and photoluminescence spectroscopy, dynamic scanning calorimetry, cyclic voltammetry, and X-ray diffraction. The charge transport properties of these new materials are studied carefully using an organic field effect transistor geometry where the charge carriers are transported over a narrow channel at the semiconductor/dielectric interface. These results are compared to bulk charge carrier mobilities using space-charge limited current (SCLC) measurements, in which the charge carrier is transported through the complete film thickness of several hundred nanometers. Finally, charge carrier mobilities are correlated with the electronic structure of the compounds. We find that in particular the thiophene-flanked copolymer PDPP[T]2-EDOT is a very promising candidate for organic photovoltaics, showing an absorption response in the near infrared region with an optical bandgap of 1.15 eV and a very high bulk hole mobility of 2.9 × 10−4 cm2 V−1 s−1 as measured by SCLC. This value is two orders of magnitudes higher than SCLC mobilities reported for other polydiketopyrrolopyrroles and is in the range of the well-known hole transporting polymer poly(3-hexylthiophene). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 639-648 [ABSTRACT FROM AUTHOR]

ABSTRACT The Sonogashira-Hagihara coupling polymerization of d-hydroxyphenylglycine-derived diiodo monomers 1-4 and platinum-containing diethynyl monomer 5 gave the corresponding polymers [poly( 1-5)-( 2-5)] with number-average molecular weights of 19,000-25,000 quantitatively. The polymers were soluble in CHCl3, CH2Cl2, THF, and DMF. CD and UV-vis spectroscopic analysis revealed that amide-substituted polymers [poly( 1-5) and poly( 2-5)] formed chiral higher-order structures in solution, while ester-substituted polymers [poly( 3-5) and poly( 4-5)] did not. Poly( 1-5) formed one-handed helices in THF/toluene mixtures, while it formed chiral aggregates in THF/MeOH mixtures. Poly( 1-5) emitted fluorescence with quantum yields ranging from 0.8 to 1.3%. The polymers usually aggregated in the solid state. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2452-2461 [ABSTRACT FROM AUTHOR]

In the solid state, crystals of both 1-(7-chloro-1,4-dihydroquinolin-4-ylidene)thiosemicarbazide-methanol-water (2/1/1), 2C10H9ClN4S·CH3OH·H2O, (I), and its hydrochloride salt {systematic name: [(7-chloro-1,4-dihydroquinolin-4-ylidene)azaniumyl]thiourea chloride}, C10H10ClN4S+·Cl−, (II), assume the imine tautomeric form, contrary to other 4-amino-7-chloroquinolines. Of particular interest are the N-C bond lengths, which have appreciable double-bond character, and the C-N-C aromatic ring bond angle. Both of these parameters have been studied extensively in 4-amino-substituted quinolines. The crystal structures of (I) and (II) in this study provide interesting examples of the amino-imino tautomerism which exists in this class of compound and is, to the best of our knowledge, hitherto unreported. [ABSTRACT FROM AUTHOR]

When copper(II) acetate is treated with the ionic liquid n-butylmethylimidazolium cyanide (BMIm-CN), in ethanol solution, two new copper coordination compounds are obtained. (BMIm)2[Cu4(CN)7] comprises a 3D coordination polymer of cyanide bridged copper ions. This anionic coordination polymer contains CuI as well as CuII ions, i.e. it is a mixed-valent compound. The polymer can be described as honeycomb structure with the BMIm+ cation being located in the cages. The second compound obtained from the chemical reaction is (BMIm)[Cu2(OAc)5][Cu(OAc)2(H2O)]2 ·C2H5OH, which can be described as double-salt. The first unit (BMIm)[Cu2(OAc)5] contains paddle wheel copper(II) acetato moieties, which are bridged by additional acetato ligands and form infinite chains. The second part of the double salt is the neutral, [Cu(OAc)2(H2O)]2 complex. These two parts as well as the co-crystallized ethanol molecule are connected through a network of hydrogen bridges. [ABSTRACT FROM AUTHOR]

Differential scanning calorimetry (DSC) analysis for ethylene/propylene copolymers synthesized in the whole composition range with a supported metallocene catalyst has been carried out. The melting/crystallization process can be determined both in the ethylene and propylene rich regions covering a comonomer composition range of up to 20%. Two peaks are detected showing two different transitions ( Tm1 and Tm2). A procedure is developed for modeling DSC melting curves by using a model previously reported by Kissin. Two contributions are considered for the copolymer crystallization in connection with a random comonomer distribution. Such model favourably describes experimental DSC curves and Tm1 and Tm2 values. The obtained parameters follow a regular trend in accordance with its physical meaning. Standard deviation for melting temperatures reveals accurate calculated values. The analysis of the parameter trend allows a fit against composition and predicting melting temperatures, yielding also accurate values. [ABSTRACT FROM AUTHOR]

ABSTRACT The microstructure of neat conjugated polymers is crucial in determining the ultimate morphology and photovoltaic performance of polymer/fullerene blends, yet until recently, little work has focused on controlling the former. Here, we demonstrate that both the long-range order along the (100)-direction and the lamellar crystal thickness along the (001)-direction in neat poly(3-hexylthiophene) (P3HT) and poly[(3,3″-didecyl[2,2′:5′,2″-terthiophene]-5,5″-diyl)] (PTTT-10) thin films can be manipulated by varying crystallization temperature. Changes in crystalline domain size impact the yield and dynamics of photogenerated charge carriers. Time-resolved microwave conductivity measurements show that neat polymer films composed of larger crystalline domains have longer photoconductance lifetimes and charge carrier yield decreases with increasing crystallite size for P3HT. Our results suggest that the classical polymer science description of temperature-dependent crystallization of polymers from solution can be used to understand thin-film formation in neat conjugated polymers, and hence, should be considered when discussing the structural evolution of organic bulk heterojunctions. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 700-707 [ABSTRACT FROM AUTHOR]

N-Heterocyclic carbenes and their heavier homologues are, in part, stabilized by delocalization of the N lone pairs into the vacant p-orbital at carbon (or a heavier Group 14 element center). These interactions are usually absent in the corresponding P-substituted species, owing to the large barrier to planarization of phosphorus. However, judicious selection of the substituents at phosphorus has enabled the synthesis of a diphosphagermylene, [(Dipp)2P]2Ge, in which one of the P centers is planar (Dipp=2,6-diisopropylphenyl). The planar nature of this P center and the correspondingly short PGe distance suggest a significant degree of PGe multiple bond character that is due to delocalization of the phosphorus lone pair into the vacant p-orbital at germanium. DFT calculations support this proposition and NBO and AIM analyses are consistent with a GeP bond order greater than unity. [ABSTRACT FROM AUTHOR]

Cr3+-doped SrGa12O19 is demonstrated to be a broadband near-infrared (650-950 nm) long-persistent phosphor whose luminescence can last for more than 2 h after ultraviolet irradiation is stopped. Detailed analysis of the photoluminescence and thermoluminescence spectra and of the persistent decay behavior of the Cr3+-doped SrGa12O19 samples indicate that the persistent energy transfer from the SrGa12O19 host to the Cr3+ ions and the filling and release of electrons into and from the shallow and deep traps through the conduction band is responsible for the long-persistent phosphorescence. [ABSTRACT FROM AUTHOR]

ABSTRACT p-n-Heptylphenylacetylene ( pHepPA) was stereoregularly polymerized in n-hexane at 25 °C using [Rh(nbd)Cl]2 catalyst (nbd: norbornadiene) and NEt3, affording the purple-red Poly( R) in 97% yield. A 80 °C heat treatment transformed Poly( R) to the black Poly( B). The Poly( R) X-ray diffraction (XRD) pattern revealed a hexagonal crystal structure comprising contracted cis-cisoid helices [ HexaPoly( R) CC]. The 80 °C heat treatment generated two tetragonal crystals: TetraPoly( B) CC containing contracted cis-cisoid helices and TetraPoly( B) CT containing stretched cis-transoid helices. The helical diameters before and after heat treatment were estimated using XRD and were consistent with molecular mechanics calculations (MMFF94 force field method). When heated at 80 °C in the solid phase, the λmax in the diffuse reflective UV-vis spectra of HexaPoly( R) CC shifted from 482 to 560 nm. Additionally, an endothermic transition occurred in the HexaPoly( R) CC differential scanning calorimetric trace at ∼80 °C. Therefore, these data corroborated the assertion that HexaPoly( R) CC thermally converted to TetraPoly( B) CC and TetraPoly( B) CT. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 5177-5183 [ABSTRACT FROM AUTHOR]

ABSTRACT Poly(3-hexylthiophene) (P3HT) is a polymer widely used in organic photovoltaic devices. Discrepancies in information exist in the literature about its morphological structure in solution and in the solid state. This work is a theoretical study, in which the structure of P3HT in the solid state is deduced from its structure in solution and comparisons with optical absorption data. The results indicate that P3HT is not planar, either in solution or in the solid state. However, the effective conjugation length in the solid state is similar to that of a planar chain. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1350-1354 [ABSTRACT FROM AUTHOR]

ABSTRACT Positron annihilation lifetime spectroscopy (PALS) is a common technique used to characterize the porosity of polymers. Here, we expand its use to the study of ordered nanoporous polymer monoliths. Polystyrene (PS) monoliths with aligned cylindrical pores ranging in diameters from 15 to 35 nm were examined. Such large pores push the boundaries of the PALS technique. To achieve robust measurement, our system used larger detectors than those typically used for monolithic polymer samples. This was done to improve data rates while sacrificing timing resolution. Pore sizes determined using PALS were consistent with measurements made using small angle x-ray scattering. In addition, PALS was able to detect the collapse of the pores when the monolithic sample was heated above the Tg of PS. Because PALS measurements are not sensitive to the nature of the order within the structure nor are they, sensitive to the open or closed nature of the pores this technique could be expanded to a variety of other sample types. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1157-1161 [ABSTRACT FROM AUTHOR]

The preparation, structures, and magnetic properties of a series of metal formate perovskites [CH3NH3][Mn xZn1− x(HCOO)3] were investigated. The isostructural solid solution can be prepared in the complete range of x=0-1. The metal-organic perovskite structures consist of an anionic NaCl type [Mn xZn1− x(HCOO)3−] framework with CH3NH3+ templates located in the nearly cubic cavities and forming hydrogen bonds to the framework. When the proportion of Mn increased (i.e., x changed from 0 to 1), the lattice dimensions and metal-oxygen and metal-metal distances show a slight, nonlinear increase because of the increased averaged metal ionic radius and the local structure distortion. Through the series, the magnetism changes from the long-range ordering of spin-canted antiferromagnetism for x≥0.40 to paramagnetism when x≤0.30, and the percolation limit was estimated to be xP=0.31(2) for this simple cubic lattice. In the low-temperature region, enhancement of magnetization and the gradual decrease and final disappearance of coercive field, remnant magnetization, and spin-flop field upon dilution were observed through this isotropic Heisenberg magnetic series. IR spectroscopic and thermal properties were also investigated. [ABSTRACT FROM AUTHOR]

A protected pentacene precursor is functionalized in the 6- and 13-positions with alkyne groups and subsequently derivatized by a copper-catalyzed azide-alkyne Huisgen cycloaddition (CuAAC) reaction. Aromatization then gives the desired pentacene derivatives. This method offers an expedient route to a range of bench-top stable, pentacene, and oligopentacene based chromophores, all derived from a single building block. These new pentacene derivatives are characterized by NMR, IR, and UV-Vis spectroscopies. X-ray crystallographic data for two derivatives is used to evaluate the prospect of electronic communication in the solid state via π-stacking interactions. [ABSTRACT FROM AUTHOR]

Cyclodextrins (CDs) are cyclic polysaccharides with nano-size, largely hydrophobic cavities, and exteriors covered with hydrophilic hydroxyl groups, making them water soluble. Threading and filling their cavities with polymer chains produces noncovalently bonded crystalline inclusion compounds (ICs). In this study, we formed fully covered, stoichiometric ICs between guest poly( L-lactic acid), poly(ε-caprolactone), and nylon-6 chains and host α-CD. Coalesced samples of all three polymers were obtained after appropriately removing the stacked α-CD host channels from their ICs. Distinct differential scanning calorimetriy (DSC) thermograms were observed for as-received and coalesced samples, with the coalesced samples crystallizing faster at higher temperatures from their melts, and this distinction was maintained even after extensive, long-time melt-annealing (hours, days, and weeks). We believe this is due to the largely unentangled chains with extended conformations that are more densely packed in the initially coalesced samples. When small amounts (∼2 wt %) of the coalesced polymers are used as self-nucleating agents for their as-received samples, the resulting self-nucleated samples show DSC thermograms similar to those of the neat coalesced polymers, including their long-time stability to melt-annealing. Coalesced polymers, whether neat or in samples they self-nucleate, may conserve their organization in the melt (largely extended and unentangled chains) for long periods, because the process of entangling the many chains influenced by a single initially extended unentangled coalesced chain, after it randomly coils, is extremely sluggish. By contrast, in melt-crystallized or solution-cast samples, polymer chains generally become fully randomly coiled, interpenetrate, and entangle after being heated and held in their melts for comparatively much shorter times. For example, we have recently observed (DSC) that ultra high molecular weight, gel-spun spectra polyethylene (PE) fibers® did not conserve or retain any memory of their as-spun and highly drawn semicrystalline morphology even after spending as little as 2 min in the melt. As a consequence of the comparison to the behavior of coalesced polymer melts, we believe that polyethylene chains in Spectra fibers® must be at least intimately dispersed within their crystalline regions, and likely partially coiled and entangled in their noncrystalline regions, thereby facilitating their rapid transformation into a full entanglement network of randomly coiling chains in the melt. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 [ABSTRACT FROM AUTHOR]

When used as a precursor for carbene ligands, the complex's reactivity and potential catalytic activity can be increased by interaction with an electrode. Keywords: carbene ligands; electronic structure; ionic liquids; solid-state structure; thermal properties EN carbene ligands electronic structure ionic liquids solid-state structure thermal properties 1 1 1 04/08/22 20220406 NES 220406 B Task-specific b polyaryl-/oligoether-substituted, imidazolium-based ionic liquids (ILs) with linker moieties enable interaction with electrochemically active surfaces. Cover Feature: A New Class of Task-Specific Imidazolium Salts and Ionic Liquids and Their Corresponding Transition-Metal Complexes for Immobilization on Electrochemically Active Surfaces (Chem. Eur. J. 20/2022). [Extracted from the article]

Front Cover: Solution‐processable, semiconducting organic materials are desirable for scaling the production of organic electronics. Having a handle on the thermal transition temperatures of the polymeric material is essential for certain fabrication steps. The unique photophysical properties of boron subphthalocyanine (BsubPc)‐containing polymers are explored to demonstrate how the BsubPc semiconducting moiety effects the solid‐state arrangement and glass transition temperature. This is reported by Kathleen L. Sampson, Benoît H. Lessard, Eunjung Cho, and Timothy P. Bender* in article number 1600592. [ABSTRACT FROM AUTHOR]