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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Synthesis and reactivity of metal clusters containing A Ru3 or Os3 triangle

Matisons, Janis Gunars. January 1983 (has links) (PDF)
Bibliography: leaves 317-318
132

Investigation of temporal and spatial characteristics of carbonyl compounds in the Atmosphere in Kaohsiung

Wu, Chun-I 29 June 2007 (has links)
The concentrations of atmospheric carbonyls were studied by the LpDNPH-Cartridge and the microcomputer air sampling device at Nanzi and Siaogang sites in Kaohsiung city. Source apportionment was determined by the factor analysis. The results showed that the highest concentrations of carbonyls was acetaldehyde (27.83 £gg/m3) at Nanzi, followed by formaldehyde (5.03 £gg/m3). At Siaogang, the highest concentrations of carbonyls was acetaldehyde (28.91 £gg/m3), followed by formaldehyde (6.92 £gg/m3). The concentrations of total carbonyls was higher at Siaogang (57.86 £gg/m3) than those at Nanzi (49.74 £gg/m3) . The concentrations of total carbonyls at Nanzi were 65.42 £gg/m3 in summer and 25.06 £gg/m3 in winter, and were 85.09 £gg/m3 in summer and 37.12 £gg/m3 in winter at Siaogang, due to the fact that summer has stronger photochemical activities than in winter. Additionally, peak rush hours of the traffics, either in the morning or at night, would result in increased concentration of Carbonyls was higher. The concentrations of atmospheric carbonyls were studied by the LpDNPH-Cartridge and the microcomputer air sampling device at Nanzi and Siaogang sites in Kaohsiung city. Source apportionment was determined by the factor analysis. The results showed that the highest concentrations of carbonyls was acetaldehyde (27.83 £gg/m3) at Nanzi, followed by formaldehyde (5.03 £gg/m3). At Siaogang, the highest concentrations of carbonyls was acetaldehyde (28.91 £gg/m3), followed by formaldehyde (6.92 £gg/m3). The concentrations of total carbonyls was higher at Siaogang (57.86 £gg/m3) than those at Nanzi (49.74 £gg/m3) . The concentrations of total carbonyls at Nanzi were 65.42 £gg/m3 in summer and 25.06 £gg/m3 in winter, and were 85.09 £gg/m3 in summer and 37.12 £gg/m3 in winter at Siaogang, due to the fact that summer has stronger photochemical activities than in winter. Additionally, peak rush hours of the traffics, either in the morning or at night, would result in increased concentration of Carbonyls was higher. Source apportionment analysis using factor analysis shows that the principle sources at Nanzi were traffic exhausts (motor, diesel, and gasoline vehicle) and stationary sources (industry, restaurant and chemical processes). The main sources at Siaogang were traffic exhausts (motor and gasoline vehicle), stationary sources (industry and restaurant) and secondary photo-chemical reactions.
133

Temporal and spatial characteristics of atmospheric carbonyl compounds in Kaohsiung Area

Huang, Chin-hung 04 July 2008 (has links)
The concentrations of atmospheric carbonyls were studied by the LpDNPH-Cartridge and the microcomputer air sampling device at Nan-Chie ¡BHsiung-Kong¡BRen-Wu and Lin-Yuan sites. Factor analysis was also used to determine the source apportionment in the Kaoshiung area. The results showed that the highest concentrations of carbonyls was acetaldehyde (27.83, 28.91, 11.46 and 10.06 £gg/m3) at four sites, followed by formaldehyde (5.03, 6.92, 7.88 and 6.59 £gg/m3), respectively. The highest concentration of total carbonyls at Nan-Chie and Hsiung-Kong was 65.42 £gg/m3 and 85.09 £gg/m3 in summer, the lowest concentration was 25.06 £gg/m3 and 37.12 £gg/m3 in winter, relatively, the highest concentration of total carbonyls at Ren-Wu and Lin-Yuan was 49.94 £gg/m3 and 55.24 £gg/m3 in winter, the lowest concentration was 24.48 £gg/m3 and 11.78 £gg/m3 in autumn. Additionally, peak rush hours of the traffics, either in the morning or at night, would result in increased concentration of Carbonyls. The results of factor analysis showed that the principle sources at Nan-Chie were traffic exhausts (diesel and gasoline vehicle) and stationary sources (metal assembly, waste treatment, pulp and restaurant). The principle sources at Hsiung-Kong were traffic exhausts (diesel, and gasoline vehicle), stationary sources (leather, chemical process and restaurant). The main sources at Ren-Wu were traffic exhausts (gasoline vehicle) and stationary sources (metal assembly, chemical process and restaurant). The main sources at Lin-Yuan were traffic exhausts (diesel vehicle) and stationary sources (metal assembly, leather, steel production and restaurant).
134

Stereoselective reactions of arene chromium tricarbonyl complexes

Goodfellow, Craig L. January 1989 (has links)
This thesis describes the application of (arene)Cr(CO)3 methodology to the Stereoselective and enantioselective synthesis of substituted arenes. Chapter one reviews the main methods of preparation and decomplexation of (arene)Cr(CO)<sub>3</sub> complexes and the electronic and steric influences of the Cr(CO)<sub>3</sub> unit on the arene. Chapter two demonstrates that the benzylic oxygen directing effect in complexation reactions operates via a direct oxygen bond to the incoming metal unit. Attachment of bulky ft-acceptor groups, such as t-butyldimethylsilyl, to the benzylic oxygen overrides this directing effect. Chapter three describes the regioselective Cl functionalisation of the cryptopine skeleton. Complexation of dihydrocrytopine gives only a single product, the relative configuration of the product being determined using an X-ray crystal structure analysis. Subsequent alkylation of the O-methyl derivative gives Cl alkylated products. Chapter four describes the regioselective ortho functionalisation of ephedrine and pseudoephedrine derivatives. Treatment of (1S,2R)-(N,O-dimethylpseudoephedrine) Cr(CO)<sub>3</sub> with n-butyllithium leads to exclusive removal of the pro-(R) ortho proton. The observed stereoselectivity arises via</em deprotonation from cyclic bidentate five-membered chelates. Chapter five describes the regioselective C4 and C5 functionalisation of (hydrocotarnine)Cr(CO)<sub>3</sub>. Complexation of 1-methylhydrocotarnine occurs to give exclusively the exo-1-methyl derivative. Further functionalisation to give the 1,5- and 4,5-dimethyl products is also described. Chapter six describes the synthesis of ortho substituted (benzaldehyde)Cr(CO)<sub>3</sub> complexes. Chiral material is available via preferential kinetic hydrolysis of, or classical separation of, the L-valinol derived imines. Chapter seven describes the Stereoselective addition of nucleophiles to (o-anisaldehyde) Cr(CO)<sub>3</sub> and (o-trialkylsilylbenzaldehyde)Cr(CO)3. With (o-anisaldehyde)- Cr(CO)<sub>3</sub> the additions are completely stereoselective giving the (RR,SS) diastereoisomer. With (o-trialkylsilylbenzaldehyde)Cr(CO)<sub>3</sub> the ratio of products is influenced by the nature of Lewis acidic species present. Chapter eight describes the Stereoselective benzylic elaboration of (o-methoxybenzyl methyl ether)Cr(CO)<sub>3</sub> achieved via selective removal of the exo benzylic proton from transition states with the methoxy groups anti to each other.
135

The development of organolead reagents in organic synthesis

Wright, Emma January 1995 (has links)
This thesis describes the synthesis of novel lead(IV) tetracarboxylates and the development of their use in carbon-carbon bond formation processes, with a particular emphasis on the construction of chiral, quaternary centres. Organolead(IV) tricarboxylates have been widely used in the functionalisation of a range of β-dicarbonyl compounds, and the available evidence suggests that these reactions occur by a ligand coupling mechanism. For this reason, by using chiral lead(IV) compounds, it may be possible to achieve a transfer of asymmetry in the bond formation reaction. A variety of achiral and chiral dicarboxylic acid ligands were synthesised, either by reaction of phthalic or camphoric anhydride with a range of diols, or by elaboration of the camphoric acid skeleton directly. A range of novel lead(IV) compounds were constructed using these ligands, both as bis-complexes and as mixed ligand complexes. The complexes were characterised by a combination of IR and NMR techniques, including <sup>207</sup>Pb NMR spectroscopy, and elemental analysis. The reactivity of some of the complexes was demonstrated via reaction with allyltributyltm. The lead(IV) complexes were used in the α-phenylation of a range of β-dicarbonyl substrates. Yields ranged from poor to excellent, but in all cases the enantiomeric excesses of the reactions were found to be no greater than 12%. Studies of these complexes by <sup>207</sup>Pb NMR spectroscopy revealed that each complex was present as more than one species in solution, which is thought to be the reason for the poor overall transfer of chirality in the phenylation reactions. The arylation procedure uses catalytic mercury(II) acetate, which can in turn introduce further potential ligands to the exchanging system. It was found that alternative catalysts, such as mercury(II) chloride, could be used successfully in the α-phenylation reaction.
136

Synthetic applications of arene chromium tricarbonyl complexes

Dolan, Peter L. January 1996 (has links)
This thesis investigates the use of arene chromium complexes as phenyl cation synthons in the synthesis of homochiral N-phenylamino esters, and the dianion formation of a series of complexed aryl ethers. Chapter 1 reviews the properties of arene chromium tricarbonyl complexes and discusses in detail the ability of some of these complexes to undergo nucleophilic aromatic substitution. Chapter 2 outlines the biological importance of homochiral N-phenylamino esters. The N-phenylation of a series of amino alcohols are first investigated both by direct reaction of haloarene complexes with amino alcohols and also via a Smiles rearrangement of an aryl ether derivative. In addition, methodology is developed for the synthesis of a series of homochiral N-phenyl-α-amino esters and N-phenyl-β-amino esters. The synthetic strategy is then applied to the synthesis of some N-phenyl-β-lactams, in particular (+)SCH 48461. Chapter 3 reviews the directed metallation of complexed and uncomplexed arene compounds and discusses the mechanism involved. The generation of dianions in a series of complexed aryl ethers is investigated. Regioselective deprotonation is observed using different alkyllithium bases and the degree of dianion formation is confirmed by electrophilic quench of the dianionic intermediates with CD<sub>3</sub>OD and TMSC1.
137

The chemistry of silyl enol ethers : titanium (IV) catalyzed reactions of 1, 3-bis (trimethylsiloxy)-4-chloro-1-methoxybuta-1, 3-diene and its application in the synthesis of Nonactic acid

Carpenter, Alexis Anne. January 1986 (has links)
No description available.
138

Infrared intensity and nuclear magnetic resonance studies of some group VIB metal chalcocarbonyl complexes

Baibich, Ione Maluf. January 1981 (has links)
Some physicochemical properties of several series of transition metal chalcocarbonyls such as ((eta)('6)-C(,6)H(,6))Cr(CO)(,2)(CX) and Cr(CO)(,5)(CX) (X = O, S, Se) have been investigated. In particular, the infrared, ('13)C and ('17)O nuclear magnetic resonance and ultraviolet spectra have been examined. The results show that the order of (sigma)-donor and (pi)-acceptor capabilities of the ligands is CO CS. The M((pi)) (--->) CX((pi)*) ultraviolet charge-transfer bands are shown to correlate with the respective (mu)'(,MCX) and ('13)C NMR data. Also, the ('13)C NMR chemical shifts and GQVFF force constants are found to be highly correlated. The ('17)O NMR spectra of the metal chalcocarbonyl complexes display chemical shifts in the opposite direction to the corresponding ('13)C ones. No correlation is found between the ('17)O shieldings and the other spectroscopic data. Reaction of Cr(CO)(,5)(CX) (X = S, Se) with halide ions (Y('-)) afforded mixtures of {Cr(CO)(,5)Y}('-) and trans-{Cr(CO)(,4)(CX)Y}('-) while Cr(CO)(,5)(CS) reacted with cyclohexylamine to give Cr(CO)(,5)(CNC(,6)H(,11)). The similarities and differences in the physicochemical behaviour of the metal chalcocarbonyls compared to related systems are discussed in the light of the different bonding patterns.
139

Synthesis and reactivity of metal clusters containing A Ru3 or Os3 triangle / by Janis Gunars Matisons

Matisons, Janis Gunars January 1983 (has links)
Bibliography: leaves 317-318 / 318 leaves (some folded) : ill ; 31 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1983
140

Metal carbonyl fluoride complexes / by Ernst Horn

Horn, Ernst January 1983 (has links)
Typescript (photocopy) / 2 microfiche in end pocket / 190 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1984

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