Organically Templated Mixed‐Valent TiIII/TiIV Phosphate with an Octahedral– Tetrahedral Open Framework

The first large‐pore, mixed‐valent titanium phosphate was hydrothermally synthesized by using elemental titanium as a starting material, and 1,3‐diaminopropane as a template. The structure displays an open framework containing octahedrally coordinated Ti^III and Ti^IV centers and tetrahedrally coordinated P centers; the diamine molecules are located within the zigzag channels (the picture shows a polyhedral representation of the structure).     

Native Fluorescence and Time Resolved Fluorescence Spectroscopic Characterization of Normal and Malignant Oral Tissues Under UV Excitation—an In Vitro Study

The present work aims to investigates the native fluorescence and time resolved fluorescence spectroscopic characterization of oral tissues under UV excitation. The fluorescence emission spectra of oral tissues at 280 nm excitation were obtained. From the spectra, it was observed that the alteration in the biochemical and morphological changes present in tissues. Subsequently, the Full width at Half Maximum (FWHM) of every individual spectra of 20 normal and 40 malignant subjects were calculated. The student’s t-test analysis reveals that the data were statistically significant (p?=?0.001). The fluorescence excitation spectra at 350 nm emission of malignant tissues confirms the alteration in protein fluorescence with respect to normal counterpart. To quantify the observed spectral differences, the two ratio variables R₁?=?I₂₇₅/I₃₁₀ and R₂?=?I₃₁₀/I₃₂₈ were introduced in the excitation spectra. Among them, the Linear Discriminant Analysis (LDA) of R₁ reveals better classification with 86.4 % specificity and 82.5 % sensitivity. The fluorescence decay kinetics of oral tissues was obtained at 350 nm emission and it was found that the decay kinetics was triple exponential. Then the ROC analysis of fractional amplitudes and component lifetime reveals that the average lifetime shows 77 % sensitivity and 70 % specificity with the cut off value 4.85 ns. Briefly, the average lifetime exhibits better statistical significance when compared to fractional amplitudes and component lifetimes.     

Poly(aniline-co-p-phenylenediamine)/MWCNT nanocomposites via in situ microemulsion: synthesis and characterization

Electrically conducting copolymer poly(aniline-co-p-phenylenediamine) and carboxylic acid functionalized multiwalled carbon nanotube (c-MWCNT) nancomposites were prepared via in situ emulsion polymerization using sodium dodecyl sulfate as an emulsifier and potassium persulfate as an oxidant. STEM and FESEM analyses showed that a tubular layer of coated copolymer film of several nanometer thicknesses was present on the c-MWCNT's surface. FT-IR spectra were endorsed the formation of nanocomposites. UV-visible absorption spectra of the diluted colloidal dispersion of nanocomposites were similar to those of the bare copolymer. Thermal stability of nanocomposites was improved by the addition of c-MWCNTs. XRD patterns of the nanocomposite samples had more crystalline nature than the bare copolymer. As the content of c-MWCNTs was increased, the electrical conductivity was increased by a charge transport function from the intrinsic electrical conductivity of MWCNTs and the formation of a highly ordered dense structure of copolymer molecules on the surface of c-MWCNTs.     

Dispersion polymerization of MMA in supercritical CO2 stabilized by random copolymers of 1H,1H–perfluorooctyl methacrylate and 2‐(dimethylaminoethyl methacrylate)

A series of random copolymers, composed of 1H,1H‐perfluorooctyl methacrylate (FOMA) and 2‐dimethylaminoethyl methacrylate (DMAEMA) were prepared as stabilizers for the dispersion polymerization of methyl methacrylate in supercritical CO₂ (scCO₂). Free‐flowing, spherical poly(methyl methacrylate) (PMMA) particles were produced in high yield by the effective stabilization of poly(FOMA‐co‐DMAEMA) containing 34–67 w/w % (15–41 m/m %) FOMA structural units. Less stabilized but micron‐sized discrete particles could be obtained even with 25 w/w % (10 m/m %) FOMA stabilizer. The result showed that the composition of copolymeric stabilizers had a dramatic effect on the size and morphology of PMMA. The particle size was controllable with the surfactant concentration. The effect of the monomer concentration and the initial pressure on the polymerization was also investigated. The dry polymer powder obtained from dispersion polymerization could be redispersed to form stable aqueous latexes in an acidic buffered solution (pH = 2.1) by an electrostatic stabilization mechanism due to the ionization of DMAEMA units in the stabilizer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1365–1375, 2008     

Synthesis and Functional Characterization of Antibiofilm Exopolysaccharide Produced by Enterococcus faecium MC13 Isolated from the Gut of Fish

The synthesis and functional characterization of an antibiofilm exopolysaccharide (EPS) from a probiotic Enterococcus faecium MC13 were investigated. The temperature of 35 °C, pH of 6.5, and salinity of 1–2 % were found to be optimum for EPS production. The sucrose (30 g?l^?1) and yeast extract (20 g?l^?1) acted as suitable carbon and nitrogen sources, respectively, which strongly influenced EPS production with yield of 11.33 and 11.91 g?l^?1. Based on the thin layer chromatography, EPS of E. faecium MC13 was found to be a heteropolysaccharide, composed of galactose and glucose sugar units with a molecular mass of 2.0?×?10⁵?Da. Fourier transform infrared spectrum analysis of the EPS revealed many predominant functional groups including hydroxyl, carboxyl, and amide groups. EPS exhibited better emulsifying and flocculating activities which is relatively similar to those of commercial polysaccharides. In vitro antioxidant inspect of EPS showed lesser antioxidant activity than that of the control ascorbic acid. Thermal behavior of EPS was different from the other EPS produced by other lactic acid bacteria. In vitro antibiofilm assay of EPS exhibited significant biofilm inhibition, especially with Listeria monocytogenes. To the best of our knowledge, this is the first report on EPS of E. faecium with strong emulsifying and flocculating activities.     

Synthesis of platestacks and microtowers of zinc by thermal evaporation

Zinc microtower and platestacks were synthesized by thermal evaporation of zinc. This synthesis was carried out under high vacuum conditions in the absence of catalyst and carrier gas. The morphology, composition and microstructural properties of the Zn nanostructures were studied by XRD, SEM and TEM. The synthesized microtowers and platestacks were single crystalline in nature. These microtowers and platestacks showed a layered structures consisting of several hexagonal nanoplates. Based on the morphological and composition analysis, we have proposed a vapor–solid mechanism to explain the growth of these nanostructures.     

New Heteronuclear Bridged Borylene Complexes That Were Derived from [{Cp*CoCl}2] and Mono‐Metal?Carbonyl Fragments

The synthesis, structural characterization, and reactivity of new bridged borylene complexes are reported. The reaction of [{Cp*CoCl}₂] with LiBH₄ ? THF at ?70 °C, followed by treatment with [M(CO)₃(MeCN)₃] (M=W, Mo, and Cr) under mild conditions, yielded heteronuclear triply bridged borylene complexes, [(μ₃‐BH)(Cp*Co)₂(μ‐CO)M(CO)₅] ( 1 – 3 ; 1 : M=W, 2 : M=Mo, 3 : M=Cr). During the syntheses of complexes 1 – 3 , capped‐octahedral cluster [(Cp*Co)₂(μ‐H)(BH)₄{Co(CO)₂}] ( 4 ) was also isolated in good yield. Complexes 1 – 3 are isoelectronic and isostructural to [(μ₃‐BH)(Cp*RuCO)₂(μ‐CO){Fe(CO)₃}] ( 5 ) and [(μ₃‐BH)(Cp*RuCO)₂(μ‐H)(μ‐CO){Mn(CO)₃}] ( 6 ), with a trigonal‐pyramidal geometry in which the μ₃‐BH ligand occupies the apical vertex. To test the reactivity of these borylene complexes towards bis‐phosphine ligands, the room‐temperature photolysis of complexes 1 – 3 , 5 , 6 , and [{(μ₃‐BH)(Cp*Ru)Fe(CO)₃}₂(μ‐CO)] ( 7 ) was carried out. Most of these complexes led to decomposition, although photolysis of complex 7 with [Ph₂P(CH₂)_nPPh₂] (n=1–3) yielded complexes 9 – 11 , [3,4‐(Ph₂P(CH₂)_nPPh₂)‐closo‐1,2,3,4‐Ru₂Fe₂(BH)₂] ( 9 : n=1, 10 : n=2, 11 : n=3). Quantum‐chemical calculations by using DFT methods were carried out on compounds 1 – 3 and 9 – 11 and showed reasonable agreement with the experimentally obtained structural parameters, that is, large HOMO–LUMO gaps, in accordance with the high stabilities of these complexes, and NMR chemical shifts that accurately reflected the experimentally observed resonances. All of the new compounds were characterized in solution by using mass spectrometry, IR spectroscopy, and ¹H, ¹³C, and ¹¹B NMR spectroscopy and their structural types were unequivocally established by crystallographic analysis of complexes 1 , 2 , 4 , 9 , and 10 .     

Syntheses and Characterization of New Vinyl‐Borylene Complexes by the Hydroboration of Alkynes with [(μ3‐BH)(Cp*RuCO)2(μ‐CO)Fe(CO)3]

Room temperature photolysis of a triply‐bridged borylene complex, [(μ₃‐BH)(Cp*RuCO)₂(μ‐CO)Fe(CO)₃] ( 1 a ; Cp*=C₅Me₅), in the presence of a series of alkynes, 1,2‐diphenylethyne, 1‐phenyl‐1‐propyne, and 2‐butyne led to the isolation of unprecedented vinyl‐borylene complexes (Z)‐[(Cp*RuCO)₂(μ‐CO)B(CR)(CHR′)] ( 2 : R, R′=Ph; 3 : R=Me, R′=Ph; 4 : R, R′=Me). This reaction permits a hydroboration of alkyne through an anti ‐ Markovnikov addition. In stark contrast, in the presence of phenylacetylene, a metallacarborane, closo‐[1,2‐(Cp*Ru)₂(μ‐CO)₂{Fe₂(CO)₅}‐4‐Ph‐4,5‐C₂BH₂] ( 5 a) , is formed. A plausible mechanism has been proposed for the formation of vinyl‐borylene complexes, which is supported by density functional theory (DFT) methods. Furthermore, the calculated ¹¹B NMR chemical shifts accurately reflect the experimentally measured shifts. All the new compounds have been characterized in solution by mass spectrometry and IR, ¹H, ¹¹B, and ¹³C NMR spectroscopies and the structural types were unequivocally established by crystallographic analysis of 2 , 5 a , and 5 b .     

Highly Efficient Direct Synthesis of Scaffold 9a,10,12,12a‐Tetrahydrobenzo[b]cyclopenta[f]pyrrolo[1,2‐d][1,4]diazepinone by Using Active Phoshomolybdic Acid

Domino coupling of furan‐2‐yl (phenyl) methanol and 2‐(1H‐pyrrol‐1‐yl) aniline has been achieved in the presence of 10 mol% phosphomolybdic acid in CH₃CN under reflux to afford the corresponding biologically active 10‐aryl‐9a,10,12,12a‐tetrahydrobenzo[b]cyclopenta[f]pyrrolo[1,2‐d][1,4]diazepin‐11(9H)‐ones in good yields. Broad substrate scope, short reaction times, environmentally benign, and operational simplicity makes this method more attractive.