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Nanoscale Co and Ni catalysts in silica were synthesized using sol–gel method for hydrogen production from steam reforming of methanol (SRM) in silicon microreactors with 50m channels. Silica sol–gel support with porous structure gives high surface area of 452.35 m 2 g −1 for Ni/SiO2 and 337.72 m 2 g −1 for Co/SiO2. TEM images show the particles size of Ni and Co catalysts to be

Silicon microreactors have been coated with mixed-metal Fe−Co Fischer−Tropsch catalysts in alumina sol−gel for conversion of syngas (CO + H2) to higher alkanes. Characterization of the nanocatalysts using scanning electron microscopy, energy-dispersive X-ray, atomic force microscopy, and Brunauer−Emmett−Teller surface area measurements, packaging, and the reaction results from a mass spectrometer at controlled temperatures (200−260 °C) and pressure (1 atm) with varying H2:CO ratios from 1:1 to 10:1 are described. The catalyst does not adequately infiltrate the 5-μm channels; it coats nicely the 25-μm channels. The initial results are consistent with a lower conversion of CO (∼32%) in a 5-μm-channel reactor and a higher conversion (∼52%) in a 25-μm-channel reactor. The selectivity to propane (∼80%) is not affected by the width of the microchannels. The activity of the sol−gel-encapsulated catalyst before and after the reactions is estimated from its magnetic properties using a vibrating sample magnetometer.

We reported the effect of carbon coating on the changes in properties of the ultra-high-molecular-weight polyethylene standard material (Hospital for Special Surgery) alter gamma irradiation in air and storage for 2 years. The coating showed a slight improvement in crystallinity (X-ray) and tensile properties (under cyclic loading) over the uncoated and irradiated control group. The oxidation level as measured by Fourier- transform infrared spectroscopy was unaffected by coating.

Anhydrous GeCl4 reacts with the closo-stannacarboranes 1-Sn-2-(SiMe3)-3-(R)-2,3-C2B4H4 (R = SiMe3 (I), Me (II), and H (III)) in the absence of solvents to give the corresponding closo-germacarboranes 1-Ge-2-(SiMe3)-3-(R)-5-(GeCl3)-2,3-C2B4H3 (R = SiMe3 (IV), Me (V), and H (VI)) in yields of 43%, 22%, and 51%, respectively. Despite the presence of two potential Lewis-acid sites, the reactions of the germacarboranes with the bases C10H8N2, C8H6N4, and C15H11N3 produced exclusively 1-(L)-2-(SiMe3)-3-(R)-5-(GeCl3)-1,2,3-GeC2B4H3 (L = C10H8N2, R = SiMe3 (VII) and Me (VIII); L = C15H11N3, R = SiMe3 (XI)) or, when L = C8H6N4, the bridged complexes 1,1‘-(2,2‘-C8H6N4)-[1-Ge-2-(SiMe3)-3-(R)-5-(GeCl3)-2,3-C2B4H3]2 (R = SiMe3 (IX), Me (X)). The reaction of IV with (η5-C5H5)Fe(η5-C5H4CH2(Me)2N) produced a 1:1 mixture of the salt {[(η5-C5H5)Fe(η5-C5H4CH2]2N(Me)2}+{GeCl3}- (XII) and 1-Ge[(η5-C5H5)Fe(η5-C5H4CH2(Me)2N)]-2,3-(SiMe3)2-5-(NMe2)-2,3-C2B4H3 (XIII), a germacarborane in which a NMe2 group replaced the GeCl3 moie...

The structure of one of the two regioisomeric products of methylation of 4-nitro-5-styrylimidazole has been assigned by single-crystal X-ray diffraction analyses.

The dianion [Os3(CO)11]2− has been prepared by stoichiometric reduction of Os3(CO)12 with potassium-benzophenone ketyl. Infrared of [Et4N][HOs3(CO)11] was determined from a single crystal X-ray analysis. The anion structure consists of an Os3 triangle. One Os atom for 3558 independent reflections with I ⩾ 3σ(I). H2Os4(CO)13 was prepared by the reaction of K2[Os3(CO)11] with Os( These basal Os atoms are bridged by two single ii-H atoms. Crystal data for H2Os4(CO)13: space group P 1 , a = 9.129(4) A

The preparation of unique penicillin derivatives containing an exocyclic allene at the 6 position (6-vinylidenepenams) is described. The synthetic scheme utilizes 6-oxopenicillinates as intermediates which stereospecifically add acetylide anions forming propargylic alcohols. Displacement of the corresponding propargylic triflates with higher order cuprate reagents and with copper(I) halides proceeds rapidly and stereospecifically. Halogen-metal exchange of the 6-(halovinylidene) -penams is described. The derived allenyl anions can be trapped by electrophiles. Conversion of selected allyl and benzhydryl esters to the corresponding carboxylic acids is described. The β-lactamase inhibitory activity of the 6-(tert-butylvinylidene)penam sulfone is documented

Closo-1-Sn-2,3-[Si(CH3)3]2-2,3-C2B4H4 (1) reacts with 1,10-phenanthroline to form the complex 1-(C12H8N2)Sn-2, 3-[Si(CH3)3]2-2,3-C2B4H4. When crystals of this complex were grown slowly from benzene, a crystalline modification (2) was obtained in which the unit cell consisted of four identical molecules of the base-stannacarborane and six benzene molecules of solvation. When the complex was sublimed, a second crystalline modification (3) was obtained whose unit cell consisted of two crystaliographically different molecules (3-1 and3-2). In all three forms the tin was not symmetrically bonded to the carborane but was slipped toward the boron side of the C2B3 face, and the phenanthroline molecules were oriented opposite to the cage carbons so that the plane of the base and the carborane faces gave acute dihedral angles. However, the three forms showed a great deal of variation in the extent of slippage and the magnitudes of the base-carborane dihedral angles. Since these distortions are common structural features of base-group 14-carborane and cyclopentadienyl systems, MNDO-SCF molecular orbital calculations were carried out on the model compounds 1-(C12H8N2)Sn-2,3-C2B4H6, 1-[C10H8N2)Sn-2, 3-C2B9H11, and [(C10H8N2)-SnC5(CH3)5]+ to determine what factors dictate the structures of these complexes. The results showed that competing bonding interactions give rise to a very broad minimum in energy as a function of slippage and base orientation. Small energy variations, such as those produced by crystal packing forces, could produce large structural changes. Complex2 crystallizes in the monoclinic space group P21/n witha=11.096 (9) A,b=26.51(2) A,c=11.729 (7) A,β=107.43 (6) ∘,U=3291 (4) A3, andZ=4. Full-matrix least-squares analysis converged atR=0.044 andRw=0.055. Complex3 crystallizes in the triclinic space group P¯1 witha=10.251 (3) A,b= 13.845(9) A;c=19.168 (9) A,α=71.12 (5) ∘,β=89.29 (3) ∘,γ=84.62 (4) ∘,U=2562 (2) A3, andZ=4. The structure refined atR=0.079 andRw=0.125.

The titled compound (3) was prepared by treating commercially available 3-(trifluoromethyl)phenothiazine successively with sodium hydride, methyl iodide, and N-bromosuccinimide, and its structure was ascertained by X-ray analysis. The reaction of 3 with certain aliphatic nitriles and LDA gave typical 7- and 6-addition products via aryne (4) in ratios of ca. 85:15, 5:6, respectively. However, treatment of 3 with certain primary and secondary amines and the corresponding lithiated amide afforded a single 7-aminated product (7) in good yields in each case

The structure of one of the two regioisomeric products of methylation of 4-nitro-5-styrylimidazole has been assigned by single-crystal X-ray diffraction analyses.

Syntheses of 4, 5, 6, 8-tetrahydro-1H, 7H-imidazo[4, 5-d] [1, 3]-diazepine-5, 8-dione (9), its 3-benzyl derivative (8), and 3- and 1-ribosyl derivatives, (12) and (13), respectively, are reported. Single-crystal x-ray analyses of 8 and 9 are also presented.

The title compound (IV) was isolated as a by-product during the course of purification of 4-nitroimidazol-5-(N′-methyl)hydrazide (II) by silica gel flash chromatography, employing chloroform-acetone (4:1) as the eluting solvent. The crystals are monoclinic, space groupP21/c,a=7.425(1),b=13.615(2),c=10.359(2) A,β=97.66(1)°,d caled=1.44 g cm−3,μ (MoKα)=1.06 mm−1,T=298 K. The number of unique reflections=2401, reflections withI≥3 σ(I)=1773;R=0.051,R w =0.061. The bond distances inIV are: N-N, 1.419(3); N-C(=0), 1.359(3); N(H)-C(CH3), 1.457(3); N(C)-C(CH3), 1.501(3); N=C, 1.316(3); C=C, 1.368(3), N-C(=N), 1.353(3); N-C(=C), 1.367(2) A.

Carbon monoxide induces the reductive elimination of two pairs of allylic ligands from Mo 2 (μ 2 -η 3 -allyl) 2 (η 3 -allyl) 2 with the accompanying cleavage of the Mo-Mo quadruple bond. Mo(η 4 -1,5-hexadiene)(CO) 4 is obtained from the reaction of 8 equiv of CO with Mo 2 (μ 2 -η 3 -allyl) 2 (η 3 -allyl) 2 . Structural data for and the reactivity of MO(η 4 -1,5-hexadiene)(CO) 4 suggest that 1,5-hexadiene is bound very weakly to molybdenum

Closo-1-Sn-2,3-[Si(CH3)3]2-2,3-C2B4H4 (1) reacts with 1,10-phenanthroline to form the complex 1-(C12H8N2)Sn-2, 3-[Si(CH3)3]2-2,3-C2B4H4. When crystals of this complex were grown slowly from benzene, a crystalline modification (2) was obtained in which the unit cell consisted of four identical molecules of the base-stannacarborane and six benzene molecules of solvation. When the complex was sublimed, a second crystalline modification (3) was obtained whose unit cell consisted of two crystaliographically different molecules (3-1 and3-2). In all three forms the tin was not symmetrically bonded to the carborane but was slipped toward the boron side of the C2B3 face, and the phenanthroline molecules were oriented opposite to the cage carbons so that the plane of the base and the carborane faces gave acute dihedral angles. However, the three forms showed a great deal of variation in the extent of slippage and the magnitudes of the base-carborane dihedral angles. Since these distortions are common structural features of base-group 14-carborane and cyclopentadienyl systems, MNDO-SCF molecular orbital calculations were carried out on the model compounds 1-(C12H8N2)Sn-2,3-C2B4H6, 1-[C10H8N2)Sn-2, 3-C2B9H11, and [(C10H8N2)-SnC5(CH3)5]+ to determine what factors dictate the structures of these complexes. The results showed that competing bonding interactions give rise to a very broad minimum in energy as a function of slippage and base orientation. Small energy variations, such as those produced by crystal packing forces, could produce large structural changes. Complex2 crystallizes in the monoclinic space group P21/n witha=11.096 (9) A,b=26.51(2) A,c=11.729 (7) A,β=107.43 (6) ∘,U=3291 (4) A3, andZ=4. Full-matrix least-squares analysis converged atR=0.044 andRw=0.055. Complex3 crystallizes in the triclinic space group P¯1 witha=10.251 (3) A,b= 13.845(9) A;c=19.168 (9) A,α=71.12 (5) ∘,β=89.29 (3) ∘,γ=84.62 (4) ∘,U=2562 (2) A3, andZ=4. The structure refined atR=0.079 andRw=0.125.

The unbridged germacarborane complexes 1-Ge-(2,2'-C 8 H 6 N 4 )-2,3-(SiMe 3 ) 2 -2,3-C 2 B 4 H 4 (I), 1-Ge-(2,2'-C 8 H 6 N 4 )-2-(SiMe 3 )-3-(Me)-2,3-C 2 B 4 H 4 (II), and 1-Ge(2,2'-C 8 H 6 N 4 )-2-(SiMe 3 )-3-(H)-2,3-C 2 B 4 H 4 (III) were synthesized, in yields of 78-84%, from reactions involving the corresponding closo-germacarborane and 2,2'-bipyrimidine in a respective ratio of 2:1 at room temperature in benzene solution over a period of 7-8 days. Although the closo-plumbacarboranes form the expected bridged complexes 1,1'-(2,2'-C 8 H 6 N 4 ) [closo-1-Pb-2,3-(SiMe 3 ) 2 -2,3-C 2 B 4 H 4 ] 2 (IV), 1,1'-(2,2'-C 8 H 6 N 4 ) [closo-1-Pb-2-(SiMe 3 )-3-(Me)-2,3-C 2 B 4 H 4 ] 2 (V), and 1,1'-(2,2'-C 8 H 6 N 4 ) [closo-1-Pb-2-(SiMe)-3-(H)-2,3-C 2 B 4 H 4 ] 2 (VI) with 2,2'-bipyrimidine in 48-58% yields, their slow formation is consistent with that of the germacarborane system in which complexation between the heterocarborane and the Lewis base was kinetically controlled

The reagent 2,2'-sulfonylbis[3-methoxy-(E,E)-2-propenenitrile] (1) was prepared by the reaction of 2,2'-sulfonyldiacetonitrile with excess trimethyl orthoformate, catalyzed by concentrated sulfuric acid. Configurational and conformational features of 1 were elucidated by single-crystal X-ray analysis. The reagent was highly reactive at room temperature with a variety of primary, secondary, and heterocyclic amines, as well as with amino acid esters of glycine, lysine, and serine, and with nucleic acid bases and nucleosides adenine/adenosine and cytosine/cytidine

(η2-cyclenP)Pt(Cl)PPh3 1 exhibits a large variety of selective reactions due to the platinum metal and cyclenphosphoranide ligand, cyclenP. Moreover, the cyclenP ligand is capable of altering many of the usual reactions and/or mechanisms at square planar platinum (II) complexes.

The preparation of Cu, Co, Fe, Cu/Co, Cu/Fe and Co/Fe nano-particle metal loaded mesoporous 1 mm spherical granular {gamma}-Al{sub 2}O{sub 3} catalysts, by combined sol-gel/oil-drop methods followed by calcination and hydrogenation steps, is accomplished. Parameters for calcination process were optimized using DTA. The properties of metal loaded {gamma}-Al{sub 2}O{sub 3} granules were compared for the preparations starting with two precursors: aluminum tri-sec-butoxide (ALTSB) and aluminum tri-iso-propoxide (ALTIP). Three sol-gel/oil-drop catalyst preparation methods; (1) Metal nitrate solutions co-entrapped-sol-gel (2) nano-particle metal oxide co-entrapped-sol-gel, and (3) Metal impregnation on preformed alumina granules, were used. Structure and composition of metal-loaded-granules were investigated using XRD, SEM, EDX, and surface area measurements (BET method). The nano-particle nature of catalysts was confirmed using SEM and X-ray diffraction. The reduction efficiency of hydrogenation of catalysts was examined by magnetic studies using a vibrating sample magnetometer (VSM). Catalysts could be effectively calcined at 450 C and the surface area values obtained were between 200-350 m{sup 2}/g, indicating the mesoporous nature of catalyst support. Parameters affecting the metal loading process were also studied, and the optimum conditions were identified and reported for reproducible synthesis of the metal loaded {gamma}-alumina granular particles. The catalyst activities of Fe, Co, and Co/Fe on alumina for the conversion of CO/H{sub 2} and CO{sub 2}/H{sub 2} mixtures were investigated using Gas chromatography (GC) with N{sub 2} as a standard carrier gas. Both, slurry-phase-batch and gas-phase-continuous-flow, reactors were used. Magnetization studies on reduced, CO/H{sub 2} post-reaction catalyst in both gas and slurry phase were performed using vibrating sample magnetometer (VSM). Magnetic studies of post-reaction Co and Fe nano-catalysts showed that the formation of carbides is higher for iron compared to cobalt. In the Fe/Co mixed catalyst, it is observed that the presence of iron enhances the cobalt oxide reduction. Catalyst with mixed metal Fe/Co compositions at 12% nitrate solutions (prepared by sol-gel/oil-drop) showed the best conversion rates for the syngas (CO+H{sub 2}). Nano-particle catalysts on sol-gel prepared mesoporous {gamma}-alumina (particularly the nano-particle metal oxide co-entrapped-sol-gel) showed higher conversion rates compared to conventional catalysts prepared by coprecipitation methods.

We have been investigating conversion of syngas (CO: H2) to higher alkanes [Fischer-Tropsch (F-T) Process] in 5 μm and 25 μm channel microreactors coated with sol-gel encapsulated Fe/Co-nanocatalysts. These nano-metal-catalysts were incorporated into the sol-gel matrix by two methods: 1) metal nitrate solutions; 2) metal oxide nanoparticles. Characterization of these catalysts containing Co and Fe in alumina and silica sol-gel has been carried out by several techniques. The surface area measurements by BET method show an average specific surface area of 285 m2/g for alumina and 300 m2/g for silica sol-gel encapsulated catalysts. In order to optimize the sol-gel preparation and deposition in the microchannels, the elemental composition of sol-gel encapsulated catalyst was examined by EDX. The SEM and AFM images of the reactors before and after deposition of the catalysts have also been studied. Hydrogenation-reduction efficiency of the activated Fe-Co catalysts and the level of poisoning after the reaction were estimated using a vibrating sample magnetometer (VSM). The result suggests more efficient reduction in the case of the nano-particle metal oxides compared to that derived from metal nitrate solutions. In overall, 85% of the catalyst is poisoned after 25 hrs of catalytic reaction. The surface area and the syngas conversion results indicate that silica sol-gel matrix may be a better catalyst support. For alumina sol-gel support, higher conversion of syn-gas is observed with 25 μm microreactor channels. For silica sol-gel, syngas conversion as high as 73% has been achieved by adding Ru as a promoter to the Fe/Co catalyst mixture.

Laser Induced Solution Deposition (LISD) is essentially a laser chemical processing with similar mechanism of the counterpart – laser chemical vapor deposition (LCVD). It is a novel method for synthesizing nanocsale particles or thin films with the combined advantages of laser chemical vapor deposition and electroless chemical deposition in solution (electrolyte). It is simple and efficient, and it can produce high quality nanoparticles or patterned uniform thin films. In this paper the nanostructured Co/CoOx particles have been fabricated by LISD technique. We have characterized the deposited materials by using scanning electron microscope (SEM), the high-resolution transmission electron microscope (HRTEM) and X-ray diffraction technique (XRD). We have found that the sizes of the deposited particles are smaller than 5 nm uniformly suspended in the solution used in the LISD deposition, and the sizes are smaller than 500 nm on the silicon substrates inserted in the deposited solution. The results by energy dispersive X-ray analysis (EDX) have indicated that there are Co peaks and O peaks, which meant there were oxygen contamination or the deposited products were cobalt oxide rather than pure cobalt nanoparticles. The X-ray diffraction has shown that we have obtained pure Co nanoparticles in some cases but we have obtained cobalt oxides in other cases, which mainly depended on the experimental conditions such as the selection of solvents and solutes as well as the selection of the lasers including the wavelength and the power of the laser beams. The studies of the magnetic properties, catalytic properties as well as their relationship of pure cobalt nanoparticles and cobalt oxide nanoparticles are in good progress and we will publish the useful results elsewhere.

[Ti(C 10 H 15 ) 2 (S 3 )] cristallise dans P2 1 /c avec a=8,770, b=19,885, c=17,20 A, β=103,75 o , Z=4; affinement jusqu'a R=0,057. Cette structure est un sandwich «decale», constitue de deux cycles η 5 -C 5 Me 5 et d'un ligand S 3 2 − formant avec Ti un cycle non plan. L'angle diedre entre le plan des trois atomes S et celui forme par Ti et deux S est de 49 o . Du fait de cette non-planeite, la liaison Ti−S la plus longue ne fait que 2,77 A

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

C 21 H 18 O 5 cristallise dans P2 1 /n avec a=12,853, b=8,183 et c=17,506 A, β=109,45°, Z=4; affinement jusqu'a R=0,052. La structure RX confirme la structure de l'un des regioisomeres formes dans la reaction de l'aryne generee a partir du 2-bromo-5,6-dihydro-1,4-dimethoxynaphtalene et du 7-methoxycyanophtalide

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

C 21 H 18 O 5 cristallise dans P2 1 /n avec a=12,853, b=8,183 et c=17,506 A, β=109,45°, Z=4; affinement jusqu'a R=0,052. La structure RX confirme la structure de l'un des regioisomeres formes dans la reaction de l'aryne generee a partir du 2-bromo-5,6-dihydro-1,4-dimethoxynaphtalene et du 7-methoxycyanophtalide

The ion cluster (C4H8O·Na+)2[2,3-(SiMe3)2-2,3-C2B4H5–]2, (2), has been prepared and the structure determined to show its extended network in the crystal lattice.

The titled compound (3) was prepared by treating commercially available 3-(trifluoromethyl)phenothiazine successively with sodium hydride, methyl iodide, and N-bromosuccinimide, and its structure was ascertained by X-ray analysis. The reaction of 3 with certain aliphatic nitriles and LDA gave typical 7- and 6-addition products via aryne (4) in ratios of ca. 85:15, 5:6, respectively. However, treatment of 3 with certain primary and secondary amines and the corresponding lithiated amide afforded a single 7-aminated product (7) in good yields in each case

C 21 H 27 B 4 N 3 SiSn-C 15 H 11 N 3 cristallise dans P1 avec affinement jusqu'a 0,040. Geometrie pentagonale bipyramidole deformee, Sn occupant un sommet

Benzyl esters of the first 6-vinylidenepenams have been prepared by reaction of 6-position propargylic triflates with higher order organocuprates. This methodology permits a great deal of versatility in the introduction of substituents at the terminal allenyl position.