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Induced Acceleration Of Phosphine Exchange In Metal Carbonyls By Pendant Groups Of Coordinated Polyphosphines, Ping Ye

Masters Theses

The kinetics and thermodynamics of isomerization of (OC)₅CrPPh₂CH₂CH(PPh₂)₂ to its linkage isomer, (OC)₅CrPPh₂CH(PPh₂)CH₂PPh₂, in chloroform-d have been studied with ³¹P{¹H} NMR.

(OC)₅Cr[η¹-PPh₂CH₂CH(PPh₂)₂] ⇄ (OC)5Cr[η¹-PPh₂CH(PPh₂)CH₂PPh₂]

The equilibrium constants for the reaction are 3.60, 2.61, 2.04, and 1.67 at 10 °C, 25 °C, 40 °C, and 53 °C, respectively. The forward reaction becomes more favorable as the temperature …

Azo Dyes Based On 1,10-Phenanthroline, Minchong Mao

Masters Theses

A series of new phenanthroline based azo-dye ligands, produced by diazotizing 5-amino-1,10-phenanthroline (5-NH₂-phen) and then coupling this intermediate to a variety of coupling components, has been synthesized and characterized. The coupling components used were β-naphthol, phenol, and 2,6-dimethylphenol, and the three dye ligands were named phen-azo-β-naphthol, phen-azo-p-phenol, and phen-azo-2,6-dimethylphenol, respectively. ¹H-NMR and IR spectra showed that the dyes exist primarily in the azo form in DMSO solution and as solids. UV-Vis spectra (in MeOH) showed intense (ε ≅ 10⁴ M^-1cm^-1) absorptions ranging from 380 nm to 500 nm for these ligands.

The …

Constancy Of Bond Dissociation Energy Ratios For Ab₂/Ab Systems, Danyu Xu

Masters Theses

G2 and G2(MP2) theories have been used to study the bond dissociation energies D⁰_m of a series of AB₂, AB₂⁺, AB₂^-, AB, AB⁺ and AB^- systems. A total of fifty-four molecules and ions have been examined, for which B = O, S or Se and A = C, S, Ge, N⁺, P⁺, As⁺, B^-, Al^- or Ga^-. Each triatomic system has sixteen valence electrons and each diatomic system has ten valence electrons. Both triplet and singlet spin …

An Expeditious Synthesis Of Β,Γ-Unsaturated Δ-Lactones: Useful Pharmacological Synthetic Intermediates, Li Xiong

Masters Theses

Two-carbon ring expansions of vinyl β-lactones, were carried out by Lewis acids (BF₃-Et₂O or Et₂AlCl) via an ionization/cation rearrangement. β,γ-unsaturated δ-lactones were produced as efficient protocols for the synthesis of bioactive substances.

Vinyl β-lactones were prepared via ring closure of corresponding unsaturated β-hydroxy acids. Differently structured substrates were examined to study the influence of the substituents on the rearrangement. Other factors, such as temperature, solvent and catalyst were also studied in search of suitable reaction conditions.

This method is moderately successful in providing fused-ring δ-lactones, but higher yields (so far total yield of 24.8%) …

A Chemical Extraction Study Of Lead Contaminated Soil From Granite City, Il, Yan Zhang

Masters Theses

Granite City, IL, surface soil ( 0-10 cm ) contaminated with lead was studied by both single- and a four-step sequential chemical extraction procedures designed to establish the partitioning, mobility and availability of lead in soil. The five fractions corresponding to the selected extractants were exchangeable, carbonates-bound, Fe-Mn oxides bound, organic matter and residual. Lead contamination of the soil was determined as a function of particle size and soil depth.

The contaminated sample had the highest lead content of 573.1 mg/kg at the 4 cm soil depth level, and on average was about 8.8 times that of background soil. Most …

Identification Of Organosulfur Compounds In Illinois Coal, Mandy N. Amin

Masters Theses

The goal of this research was to identify representative organosulfur compounds in Illinois coal which are removed by a mild, chemical desulfurization procedure. Pyridine was used to extract three raw Illinois coals. Coal with a significant amount of elemental sulfur was treated with 1:1 HCl/HF followed by lithium aluminum hydride before pyridine extraction. Pyridine soluble extracts were extracted with tetrahydrofuran. Nickel boride desulfurization was performed on the soluble extracts of the three coals. The before and after desulfurized THF soluble extracts were fractionated and purified by liquid chromatography and the eluents were anlyzed by gas chromatography/mass spectrometry to characterize the …