Physical Sciences and Mathematics Commons^™

A Ring-Closing Strategy For The Synthesis Of Β,Γ-Unsaturated Δ-Lactones, Erbing Hua

Masters Theses

Spiro β,γ-unsaturated δ-lactones and fused β,γ-unsaturated δ-lactones are integral to a large number of naturally occurring compounds exhibiting a diverse range of biological activity. A new synthetic route to β,γ-unsaturated δ-lactones, consisting of a three-step sequence, has been investigated for the synthesis of these kinds of pharmacological intermediates. Ring closure of a β-hydroxy acid by dehydration, providing a 4-vinyl substituted β-lactone, and its ring expansion/rearrangement are the two key steps in this protocol. The results have proved that this new method is efficient and quite expeditious. One spiro and four fused β,γ-unsaturated δ-lactones were synthesized through this protocol albeit in …

Computational Studies Of Constant Bond Dissociation Enthalpy Ratios And Novel Structures For [H3, B, C, F]+, Le Li

Masters Theses

This thesis describes two separate computational chemistry projects. The first project is a study of constant bond dissociation enthalpy ratios, and the second project is a study of the rearrangement and fragmentation processes on the singlet potential energy surface of the [H₃, B, C, F]⁺ system.

G2 and G2(MP2) enthalpies have been calculated for isoelectronic AB₂ systems with singlet-linear, singlet-nonlinear, triplet-linear, and triplet-nonlinear electronic states and geometries, and for isoelectronic AB systems with singlet and triplet electronic states. For these systems, A = B^-, Al^-, Ga^-, C, Si, Ge, N …

Pentacarbonyl Derivatives Of Polydentate Phosphines, Yi Zang

Masters Theses

Four phosphines (Ph₂P)₂C=CHPPh₂, (p-tol)₂PCH₂P(p-tol)₂, (o-tol)₂PCH₂P(o-tol)₂, Ph₂PCH₂P(p-tol)₂ and their pentacarbonyltungsten complexes have been prepared and studied as part of a continuous investigation of polydentate phosphines that are coordinated as monodentate ligands. The ligand, (Ph₂P)₂C=CHPPh₂, was prepared by base-catalyzed addition of Ph₂PH to Ph₂PC=CPPh₂. Reaction of this ligand with (OC)₅WNH₂Ph led to formation …

The Synthesis Of 2-Indenylphenols: Potential Ligands For Transition Metals, Yoon Jae Kim

Masters Theses

The syntheses of 2-(2-indenyl)-phenol and 2-(1-indenyl)-phenol via a three-step sequence have been developed. In the first steps of the sequence, a Grignard reagent formed from 2-iodoanisole or 2-bromoanisole reacted with 1-indanone or 2-indanone in yields that ranged from 11.3% to 67.2%. The second step consisted of acid-catalyzed dehydration of the alcohol formed in step 1 to make a 2-inenyl anisole; yields in the second step were 45.2% to nearly quantitative. Finally, demethylation of the 2-indenyl anisole was achieved with AlBr₃ in ethanethiol in yields ranging from 52.9% to 0 %. Each product was characterized by ¹H and ^{13 …}

Linkage Isomers Of Tungsten Carbonyl Complexes Of Ph₂Pch₂Pphch₂Pph₂, Chaminda P. Gamage

Masters Theses

The linkage isomers (CO)₅W[η¹-PPh₂CH₂PPhCH₂PPh₂], 1, and (CO)₅ W[η¹-PPh(CH₂PPh₂)₂], 2, have been synthesized from the reaction of (OC)₅W(NH₂Ph) and Ph₂PCH₂PPhCH₂PPh₂. In addition, linkage isomers (CO)₅W[μ-PPh₂CH₂PPhCH₂PPh₂]-W(CO)₅, 3, and (CO)₅W{μ-PPh₂CH₂PPh[W(CO)₅] CH₂PPh₂}, 4, have been prepared. Attempts to obtain (OC)₅WPPh₂CH …

Computational Studies Of Regularities In Bond Dissociation Enthalpies And Interactions Of Acetylthiocholine With Solvent Molecules, Wencui Zheng

Masters Theses

This thesis reports the results of two different research projects. One project is an evaluation of the feasibility of applying constant bond dissociation enthalpy ratios to neutral molecules for which one atom is from group 13 or group 17 and the other atom is from group 16. The other project attempts to validate the proposal that the aromatic residues lining the acetylcholinesterase (AChE) gorge will induce entry of acetylthiocholine (ATCh) into the gorge in a manner similar to that of the neural transmitter acetylcholine.

A total of thirty AB₂ and AB molecules have been examined, where A = B, …

The Reactivity Of Boron And Aluminum Compounds With Silica Gel Surfaces, Jeannine M. Christensen

Masters Theses

The unmodified silica gel surface contains isolated silanols, vicinal silanols, and siloxane species. Silica gels can be thermally and/or chemically treated to obtain a desired surface. Hexamethyldisilazane (HMDS) was used to chemically modify the silica gel to obtain a surface that contains vicinal silanol groups and siloxane species. The silica gel was thermally treated at 600°C to create a surface that contains isolated silanols and siloxane species. Four types of silica gels (unmodified, 600°C, HMDS and 600°C/HMDS) were reacted with three boron compounds. The boron compounds used were boron trichloride (BCl₃), triethyl borane (B(CH₂CH₃) …