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Abstract: A novel class of scintillating materials, which are nanocomposites of known scintillators, is described. These nanocomposite materials are expected to have improved properties with respect to the properties of the bulk scintillators from which they are derived. Improvements include enhanced light output, reduced cost and greater size scalability. Optical properties of the nanocomposite phosphor components are described, with emphasis on the origin of the enhanced light yield. Finally, results from our first nanocomposite scintillator, including photopeak measurements, are described. The photopeak measurements demonstrate the proof-of-principle of the nanocomposite scintillator concept. [Copyright &y& Elsevier]

Abstract: The Raman and infrared spectra of a series of 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids ([C2-4MIM][BF4]) are reported and analyzed using Density Functional Theory (DFT) and RHF methods at the 6-311+G(2d,p) computational level. The B3LYP (DFT) and RHF calculations reproduce the vibrational spectra of 1-ethyl-3-methyl imidazolium tetrafluoroborate [EMIM][BF4], 1-propyl-3-methyl imidazolium tetrafluoroborate [PMIM][BF4] and 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF4] using correction factors of 0.963–0.967 (DFT) and 0.913–0.916 (RHF) with correlation coefficients R 2 of 0.999 using the fully optimized structures. Theoretical (DFT) alkyl side chain conformational changes in the 1-alkyl-3-methyl tetrafluoroborate ionic liquids have only a limited effect on the theoretical gas phase vibrations. The gas phase molecular structures of the [C2–4MIM][BF4] ion pairs suggest hydrogen bonding interactions between the fluorine atoms of the BF4 − anion and the C2 hydrogen on the imidazolium ring. Additional interactions are observed between [BF4] and H atoms on the adjacent alkyl side chains in all polymorphic structures. [Copyright &y& Elsevier]

Abstract: Ionic liquids are salts that are liquid at or near room temperature. Their wide liquid range, good thermal stability, and very low vapor pressure make them attractive for numerous applications. The general approach to creating ionic liquids is to employ a large, unreactive, low symmetry cation with and an anion that largely controls the physical and chemical properties. The most common cations used in ionic liquids are N-alkylpyridinium and N,N′-dialkylimidazolium. Another very effective cation for the creation of ionic liquids is tetraalkylphosphonium, [PR1R2R3R4]+. The alkyl groups, R n , generally are large and not all the same. The halide salts of several phosphonium cations are available as starting materials for metathesis reactions used to prepare ionic liquids. The large phosphonium cations can combine with relatively large anions to make viscous but free flowing liquids with formula mass greater than 1000 gmol−1. Some other more massive salts are waxes and glasses. The synthesis and the physical, chemical, and optical properties of phosphonium-ionic liquids having anions with a wide range of masses were measured and are reported here. [Copyright &y& Elsevier]

Chemical reduction of 2,4,6-tricyano-1,3,5-triazine, TCT, results in the formation of an unstable radical anion that undergoes immediate dimerization at a ring carbon to form [C[sub 12]N[sub 12]][sup 2-] , [TCT][sub 2, sup 2-] , characterized by a long 1.570 (4) Å central C-C bond. [TCT][sub 2, sup 2-] can decompose into the radical anion of 4,4&;prime;,6,6'-tetracyano-2,2'-bitriazine, [TCBT][sup •-], the one-electron reduced form of planar (D[sub 2h]) TCBT, which is also structurally characterized as the [TMPD][TCBT] charge-transfer complex (TMPD = N,N,N'N'-tetramethyl-p-phenylenediamine) with a 1.492 (2) Å central sp²-sp² C-C bond. Although crystals could not be obtained for the radical anion [TCBT][sup •-], the electrochemistry (E° = +0.03 V), EPR (g = 2.003, ²A[sub [sup 14]N] = 3.347 G, and [sup 4]A[sub [sup 14]N] = 0.765 G and a line width of 0.24 G), and theoretical calculations support the formation of [TCBT][sup •-]. In addition, thermolysis of [TCT][sub 2, sup 2-] yields [TCBT][sup •-]. Chemical reduction of 2,4,6-tricyanobenzene, TCB, forms an unstable radical anion that immediately undoergoes dimerization at a ring carbon to form [C[sub 12]H[sub 6]N[sub 6]][sup 2-], [TCB][sub 2, sup 2-], which has a long 1.560 (5) Å central C-C bond. Reaction of TCT with tetrathiafulvalene (TTF) forms structurally characterized [TTF] [TCT], and in the presence of water, TCT hydrolyzes to 2,4-dicyano6-hydroxy-s-triazine, DCTOH. In contrast, the reaction of TCT with TMPD forms [TMPD] [TCT], which in the presence of water forms structurally characterized [HTMPD][sup +][DCTO][sup -]. [ABSTRACT FROM AUTHOR]

Presents structure and magnetic studies of copper(II) benzoate nitroxide dimers and chains. Synthesis of copper(II) benzoate dimers and linear chains; Magnetic properties; Structure refinement parameters; General mechanism for the formation of copper dimers and chains.

Abstract: Ionic liquids, with their vast applications, have been touted as being thermally stable to very high temperatures. However, decomposition not detected by standard TGA and NMR techniques are observed with spectroscopic techniques sensitive enough to see small amounts of impurities. Decomposition temperatures of common ionic liquids appear to occur at hundreds of degrees below those temperatures previously reported. [Copyright &y& Elsevier]

By using the tripodal tetradentate ligand tris(2-benzimidazolylmethyl)amine (H[sub 3]ntb), which can have several charge states depending on the number of secondary amine protons, mononuclear octahedral and dinuclear trigonal bipyramidal Fe(lll) complexes were prepared. The reaction of mononuclear octahedral [Fe[sup III](H[sub 3]ntb)Cl[sub 2]]ClO[sub 4], 1, with 3 equiv of sec-butylamine in methanol led to the formation of mononuclear cis-dimethoxo octahedral Fe[sup III](H[sub 2]ntb)(OMe)[sub 2], 2. One equivalent of the sec-butylamine was used to generate the monoanionic H[sub 2]ntb[sup -] ligand where one of the three amines in the benzimidazolyl groups was deprotonated. The remaining 2 equiv were used to generate two methoxides that were coordinated to the octahedral Fe(lll) ion in a cis fashion as demonstrated by the chlorides in 1. Reaction of 1 with excess (7 equiv) sec-butylamine generated the doubly deprotonated dianionic Hntb[sup 2-] that stabilized the dinudear μ-oxo Fe[sup III][sub 2]O(Hntb)[sub 2], 3, adopting a five-coordinate trigonal bipyramidal geometry. The magnetic data for 3 are consistent with the antiferromagnetically coupled Fe[sup III] (S = 5/2) sites with the coupling constant J = -127 cm[sup -1]. [ABSTRACT FROM AUTHOR]

Examines the structure and magnetic properties of metal complexes of N-4-pyridylbenzamide. Supramolecular patterns of crystalline networks; Formation of noncovalent interactions in crystalline solids; Occurrence of intermolecular hydrogen bond interaction.

Choline geranate (also described as Choline And GEranic acid, or CAGE) has been developed as a novel biocompatible antiseptic material capable of penetrating skin and aiding the transdermal delivery of co-administered antibiotics. The antibacterial properties of CAGE were analyzed against 24 and 72 hour old biofilms of 11 clinically isolated ESKAPE pathogens (defined as Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter sp, respectively), including multidrug resistant (MDR) isolates. CAGE was observed to eradicate in vitro biofilms at concentrations as low as 3.56 mM (0.156% v:v) in as little as 2 hours, which represents both an improved potency and rate of biofilm eradication relative to that reported for most common standard-of-care topical antiseptics in current use. In vitro time-kill studies on 24 hour old Staphylococcus aureus biofilms indicate that CAGE exerts its antibacterial effect upon contact and a 0.1% v:v solution reduced biofilm viability by over three orders of magnitude (a 3log10 reduction) in 15 minutes. Furthermore, disruption of the protective layer of exopolymeric substances in mature biofilms of Staphylococcus aureus by CAGE (0.1% v:v) was observed in 120 minutes. Insight into the mechanism of action of CAGE was provided with molecular modeling studies alongside in vitro antibiofilm assays. The geranate ion and geranic acid components of CAGE are predicted to act in concert to integrate into bacterial membranes, affect membrane thinning and perturb membrane homeostasis. Taken together, our results show that CAGE demonstrates all properties required of an effective topical antiseptic and the data also provides insight into how its observed antibiofilm properties may manifest. [ABSTRACT FROM AUTHOR]

Ionic liquids containing lanthanide halide anions give the opportunity to investigate magnetic behaviour in non-ordered systems. Reported herein is the synthesis and characterization of ionic liquids containing a series of lanthanide halide anions, with the resulting materials displaying unusual behaviour below 50 K. Specifically, the ionic liquid structural glass formation appears to drive magnetic behaviour due to cluster formation of the anions during rapid cooling. This system presents a possible probe to study the dynamics of glass forming materials. [ABSTRACT FROM AUTHOR]

Biofilm-protected microbial infections in skin are a serious health risk that remains to be adequately addressed. The lack of progress in developing effective treatment strategies is largely due to the transport barriers posed by the stratum corneum of the skin and the biofilm. In this work, we report on the use of Ionic Liquids (ILs) for biofilm disruption and enhanced antibiotic delivery across skin layers. We outline the syntheses of ILs, analysis of relevant physicochemical properties, and subsequent neutralization effects on two biofilm-forming pathogens; Pseudomonas aeruginosa and Salmonella enterica. Further, the ILs were also examined for cytotoxicity, skin irritation, delivery of antibiotics through the skin, and treatment of biofilms in a wound model. Of the materials examined, choline-geranate emerged as a multipurpose IL with excellent antimicrobial activity, minimal toxicity to epithelial cells as well as skin, and effective permeation enhancement for drug delivery. Specifically, choline-geranate was comparable with , or more effective than, bleach treatment against established biofilms of S. enterica and P. aeruginosa, respectively. In addition, cholinegeranate increased delivery of cefadroxil, an antibiotic, by > 16- fold into the deep tissue layers of the skin without inducing skin irritation. The in vivo efficacy of choline-geranate was validated using a biofilm-infected wound model (> 9 5% bacterial death after 2-h treatment). This work establishes the use of ILs for simultaneous enhancement of topical drug delivery and antibiotic activity. [ABSTRACT FROM AUTHOR]

A new strategy employs amorphous melts of active pharmaceuticalagents, which are formed with metal chlorides, including ZnCl2, through speciation ambiguity. The Lewis acidic, bioinorganicionic liquid formulations improve shelf life and water solubilityand eliminate issues related to crystal polymorphism. This broad-rangingapproach produces thermally robust chlorometallate preparations foruse as lotions, antibiofilm agents, and in situations without refrigeration. [ABSTRACT FROM AUTHOR]

Analytical capabilities to identify dyes associated with structurally robust wool fibers would critically assist crime-scene and explosion-scene forensics. Nondestructive separation of dyes from wool, removal of contaminants, and dye analysis by MALDI- or ESI-MS, were achieved in a single-pot, ionic liquid-based method. Ionic liquids (ILs) that readily denature the wool a-keratin structure have been identified and are conducive to small volume, high-throughput analysis for accelerated threat-response times. Wool dyed with commercial or natural, plant-based dyes have unique signatures that allow classification and matching of samples and identification of dyestuffs. Wool released 0.005 mg of dye per mg of dyed wool into the IL, allowing for analysis of single-thread sample sizes. The IL + dye mixture promotes sufficient ionization in MALDI-MS: addition of common MALDI matrices does not improve analysis of anionic wool dyes. An inexpensive, commercially available tetrabutylphosponium chloride IL was discovered to be capable of denaturing wool and was determined to be the most effective for this readily fieldable method. [ABSTRACT FROM AUTHOR]

[Ni(HF2)(pyz)2]X {pyz = pyrazine; X = PF6- (1), SbF6- (2)} were structurally characterized by synchrotron X-ray powder diffraction and found to possess axially compressed NiN4F2 octahedra. At 298 K, 1 is monoclinic (C2/c) with unit cell parameters, a = 9.9481(3), b = 9.9421(3), c = 12.5953(4) Å, and β = 81.610(3)° while 2 is tetragonal (P4/nmm) with a = b = 9.9359(3) and c = 6.4471(2) Å and is isomorphic with the Cu-analogue. Infinite one-dimensional (1D) Ni-FHF-Ni chains propagate along the c-axis which are linked via μ-pyz bridges in the ab-plane to afford three-dimensional polymeric frameworks with PF6- and SbF6- counterions occupying the interior sites. A major difference between 1 and 2 is that the Ni-F-H bonds are bent (157°) in 1 but are linear in 2. Ligand field calculations (LFT) based on an angular overlap model (AOM), with comparison to the electronic absorption spectra, indicate greater π-donation of the HF2- ligand in 1 owing to the bent Ni-F-H bonds. Magnetic susceptibility data for 1 and 2 exhibit broad maxima at 7.4 and 15 K, respectively, and λ-like peaks in dχT/dT at 6.2 and 12.2 K that are ascribed to transitions to long-range antiferromagnetic order (TN). Muon-spin relaxation and specific heat studies confirm these TN's. A comparative analysis of χ vs T to various 1D Heisenberg/Ising models suggests moderate antiferromagnetic interactions, with the primary interaction strength determined to be 3.05/3.42 K (1) and 5.65/6.37 K (2). However, high critical fields of 19 and 37.4 T obtained from low temperature pulsed-field magnetization data indicate that a single exchange constant (J1D) alone is insufficient to explain the data and that residual terms in the spin Hamiltonian, which could include interchain magnetic couplings (J), as mediated by Ni-pyz-Ni, and single-ion anisotropy (D), must be considered. While it is difficult to draw absolute conclusions regarding the magnitude (and sign) of J and D based solely on powder data, further support offered by related Ni(II)-pyz compounds and our LFT and density-functional theory (DFT) results lead us to a consistent quasi-1D magnetic description for 1 and 2. [ABSTRACT FROM AUTHOR]

Room temperature ionic liquids, or RTILs, based on tetraalkylphosphonium (PR +) cations were used as the basis of a platform that enables separation of dyes from textiles, extraction of dyes from aqueous solution, and identification of the dyes by MALDI-MS in a single experimental step for forensic purposes. Ionic liquids were formed with PR cations and ferulate (FA), a-cyano-4-hydroxycirmamate (CHCA), and 2,5-dihydroxy- benzoate (DHB) anions. The use of tetraalkylphosphoniwn- based ionic liquids in MALDI-MS allowed detection of small molecule dyes without addition of a traditional solid MALDI matrix. [ABSTRACT FROM AUTHOR]

The promotion for hydrogen release from ammonia-borane (AB) was observed in the presence of ZIF-8. Even at concentrations of ZIF-8 as low as 0.25 mol %, a reduction of the onset temperature for dehydrogenation accompanies an increase in both the rate and amount of hydrogen released from AB. [ABSTRACT FROM AUTHOR]