Synthesis, crystal structure and luminescent properties of one new inorganic-organic hybrid compound [O2NBzQL]4[Cd(SCN)4(NCS)2] (O2NBzQL=1-(4'-NO2-benzyl)quinolinium cation)

A new inorganic–organic hybrid compound [O₂NBzQL]₄[Cd(SCN)₄(NCS)₂] (O₂NBzQL = 1-(4′-NO₂-benzyl)quinolinium cation) has been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Cd(II) atom has an distorted octahedral environment with an N₄S₂ donor set. In solid state there are three types of face-to-face π–π interactions between adjacent cations and multiform C–H?S and C–H?N hydrogen bonds between [O₂NBzQL]⁺ cations and cadmium thiocyanate anions. The luminescent properties of the title compound were both investigated in H₂O solution and in solid state at room temperature, respectively.     

Ultra-high resolution 17O solid-state NMR spectroscopy of biomolecules: a comprehensive spectral analysis of monosodium L-glutamate·monohydrate

Monosodium L-glutamate monohydrate, a multiple oxygen site (eight) compound, is used to demonstrate that a combination of high-resolution solid-state NMR spectroscopic techniques opens up new possibilities for (17)O as a nuclear probe of biomolecules. Eight oxygen sites have been resolved by double rotation (DOR) and multiple quantum (MQ) NMR experiments, despite the (17)O chemical shifts lying within a narrow shift range of <50 ppm. (17)O DOR NMR not only provides high sensitivity and spectral resolution, but also allows a complete set of the NMR parameters (chemical shift anisotropy and electric-field gradient) to be determined from the DOR spinning-sideband manifold. These (17)O NMR parameters provide an important multi-parameter comparison with the results from the quantum chemical NMR calculations, and enable unambiguous oxygen-site assignment and allow the hydrogen positions to be refined in the crystal lattice. The difference in sensitivity between DOR and MQ NMR experiments of oxygen in bio/organic molecules is also discussed. The data presented here clearly illustrates that a high resolution (17)O solid-state NMR methodology is now available for the study of biomolecules, offering new opportunities for resolving structural information and hence new molecular insights.     

A Nonpolar,Nonamphiphilic Molecule Can Accelerate Adsorption of Phospholipids and Lower Their Surface Tension at the Air/Water Interface

The adsorption dynamics of a series of phospholipids (PLs) at the interface between an aqueous solution or dispersion of the PL and a gas phase containing the nonpolar, nonamphiphilic linear perfluorocarbon perfluorohexane (PFH) was studied by bubble profile analysis tensiometry. The PLs investigated were dioctanoylphosphatidylcholine (DiC₈‐PC), dilaurylphosphatidylcholine, dimyristoylphosphatidylcholine, and dipalmitoylphosphatidylcholine. The gas phase consisted of air or air saturated with PFH. The perfluorocarbon gas was found to have an unexpected, strong effect on both the adsorption rate and the equilibrium interfacial tension (γ_eq) of the PLs. First, for all of the PLs, and at all concentrations investigated, the γ_eq values were significantly lower (by up to 10 mN m^?1) when PFH was present in the gas phase. The efficacy of PFH in decreasing γ_eq depends on the ability of PLs to form micelles or vesicles in water. For vesicles, it also depends on the gel or fluid state of the membranes. Second, the adsorption rates of all the PLs at the interface (as assessed by the time required for the initial interfacial tension to be reduced by 30 %) are significantly accelerated (by up to fivefold) by the presence of PFH for the lower PL concentrations. Both the surface‐tension reducing effect and the adsorption rate increasing effect establish that PFH has a strong interaction with the PL monolayer and acts as a cosurfactant at the interface, despite the absence of any amphiphilic character. Fitting the adsorption profiles of DiC₈‐PC at the PFH‐saturated air/aqueous solution interface with the modified Frumkin model indicated that the PFH molecule lay horizontally at the interface.     

Neuron cells uptake of polymeric microcapsules and subsequent intracellular release

Neuron cells uptake of biodegradable and synthetic polymeric microcapsules functionalized with aggregates of gold nanoparticles incorporated into their shells is demonstrated in situ. In addition to traditionally used optical microscopy, electron microscopy is used both for higher-resolution imaging and for confirming the uptake by focused ion beam cross-sectioning of specific cells in situ. Subsequently, physical methods of release are compared to chemical methods wherein laser-induced intracellular release of dextran molecules into the cytosol of hippocampal neuron cells is studied in comparison to biodegradation. Implications of this work for neuroscience, bio-medicine and single cell studies are discussed.     

Citrus essential oil of Nigeria. Part V: Volatile constituents of sweet orange leaf oil (Citrus sinensis)

The volatile oils extracted from leaves of eight cultivars of Citrus sinensis (L) Osbeck were comprehensively analysed by a combination of GC and GC-MS. Fifty four constituents accounting for 82.3-98.2% were identified. Sabinene (20.9-49.1%), delta-3-carene (0.3-14.3%), (E)-beta-ocimene (4.4-12.6%), linalool (3.7-11.1%) and terpinen-4-ol (1.7-12.5%) were the major constituents that are common to all the volatile oils. In addition, a cluster analysis was carried out and indicated at least four different chemotypes for the C. sinensis cultivars.     

Ligand-accelerated cross-coupling of C(sp2)-H bonds with arylboron reagents

A ligand-accelerated Pd(II)-catalyzed C(sp(2))-H/arylboron cross-coupling reaction of phenylacetic acid substrates is reported. Using Ac-Ile-OH as the ligand and Ag(2)CO(3) as the oxidant, a fast, high-yielding, operationally simple, and functional group-tolerant protocol has been developed for the cross-coupling of phenylacetic acid substrates with aryltrifluoroborates. This ligand scaffold has also been shown to improve catalysis using 1 atm O(2) as the sole reoxidant, which sheds light on the path forward in developing optimized ligands for aerobic C-H/arylboron cross-coupling.     

Direct detection of fatty acid ethyl esters using low temperature plasma (LTP) ambient ionization mass spectrometry for rapid bacterial differentiation

Low temperature plasma mass spectrometry (LTP-MS) was employed to detect fatty acid ethyl esters (FAEE) from bacterial samples directly. Positive ion mode FAEE mass spectrometric profiles of sixteen different bacterial samples were obtained without extraction or other sample preparation. In the range m/z 200-300, LTP mass spectra show highly reproducible and characteristic patterns. To identify the FAEE's associated with the characteristic peaks, accurate masses were recorded in the full scan mode using an LTQ/Orbitrap instrument, and tandem mass spectrometry was performed. Data were examined by principal component analysis (PCA) to determine the degree of differentiation possible amongst different bacterial species. Gram-positive and gram-negative bacteria are readily distinguished, and 11 out of 13 Salmonella strains show distinctive patterns. Growth media effects are observed but do not interfere with species recognition based on the PCA results.     

Frustrated Lewis pairs beyond the main group: cationic zirconocene-phosphinoaryloxide complexes and their application in catalytic dehydrogenation of amine boranes

The cationic zirconocene-phosphinoaryloxide complexes [Cp(2)ZrOC(6)H(4)P(t-Bu)(2)][B(C(6)F(5))(4)] (3) and [Cp*(2)ZrOC(6)H(4)P(t-Bu)(2)][B(C(6)F(5))(4)] (4) were synthesized by the reaction of Cp(2)ZrMe(2) or Cp*(2)ZrMe(2) with 2-(diphenylphosphino)phenol followed by protonation with [2,6-di-tert-butylpyridinium][B(C(6)F(5))(4)]. Compound 3 exhibits a Zr-P bond, whereas the bulkier Cp* derivative 4 was isolated as a chlorobenzene adduct without this Zr-P interaction. These compounds can be described as transition-metal-containing versions of linked frustrated Lewis pairs (FLPs), and treatment of 4 with H(2) under mild conditions cleaved H(2) in a fashion analogous to that for main-group FLPs. Their reactivity in amine borane dehydrogenation also mimics that of main-group FLPs, and they dehydrogenate a range of amine borane adducts. However, in contrast to main-group FLPs, 3 and 4 achieve this transformation in a catalytic rather than stoichiometric sense, with rates superior to those for previous high-valent catalysts.