Other Chemistry Commons^™

Thermal Decomposition Of Silane, Mark S. Gordon, David R. Gano, J. Stephen Binkley, Michael J. Frisch

Mark S. Gordon

The essential features of the potential energy surface for the thermal decomposition of silane have been calculated with extended basis sets, augmented by correlation corrections. It is predicted that the transition state for the molecular elimination lies 56.9 kcaljmol above silane. For the reverse reaction, the transition state is less than 2 kcal/mol above the separated fragments, silylene and molecular hydrogen, but 4.8 kcal/mol above a long-range potential well. In the latter, the silylene-H2 separation is 1.78 A, and the bond in H2 has stretched by more than 0.05 A. This indicates a significant electronic interaction between the fragments even …

Some Useful Synthetic Applications Of Gold's Reagent, John T. Gupton

Chemistry Faculty Publications

While looking for some appropriate research projects, I had been impressed by and interested in the work of Danishefsky¹ and others² regarding the use of "Eschenmoser's salt" (1). During the course of a literature search on an industrial project, we came across an article by Gold,³ which described the preparation of a rather interesting vinylogous iminium salt (2). The name assigned to this compound was [3-(dimethylamino)-2-azaprop-2-en-1-ylidene]dimethylammonium chloride. This terminology seemed a little cumbersome for routine discussions so we adopted the name "Gold's Reagent" for compound 2. Although the reagent had been prepared³ in 1960, very little …

A Theoretical Investigation Of The One– And Two–Photon Properties Of Porphyrins, Mark Masthay, Leonore A. Findsen, Brian M. Pierce, David F. Bocian, James S. Lindsey, Robert R. Birge

Chemistry Faculty Publications

The one‐ and two‐photon properties of free base porphin, free base porphin dianion, and the 2,4‐substituted diformyl and divinyl analogs of these molecules are studied using a semiempirical SCF‐MO formalism (CNDO‐π‐SCF‐MO‐PSDCI) including extensive single and double configuration interaction. Strongly two‐photon allowed states are predicted to lie in the Soret region as well as in the region between the Soret and visible bands. A number of the two‐photon allowed states in the Soret region are predicted to have two‐photon absorptivities exceeding 100×10−50 cm4 s molecule−1 photon−1. The calculations indicate that the visible (Q) states are well characterized by the …

Ion Selective Electrodes Based On Aza- Substituted Crown Ethers, Lisa Ann Wellington

Retrospective Theses and Dissertations

A cation-responsive electrode system has been developed which incorporates aza-substituted crown ethers as ligands. In a novel application, uncomplexed crown ethers were used in the pelletized form for ionic transport. Electrodes have been produced which can be conditioned for a particular ion and following their use, be reconditioned and reused for other ions. Preparation method and lifetime studies are included.

The responses of two crown ethers with plasticizers were evaluated for thirteen representative cations. The concentration range covered in each evaluation was 1 x 10^-1 to 1 x 10^-7 M. For those ions exhibiting Nernstian or near-Nernstian response, …

The Use Of Scheffe-Equivalent Equations To Predict Physical Properties Of Neoprene, Cheng Y. Loh

Retrospective Theses and Dissertations

The goal of this study is to find a more organized and directed approach to build models for mixture systems. An attempt is made to generate and then compare Scheffe (mixture) models with those generated by McGee using the ‘conventional’ method for neoprene data. The models are judged on their ability to predict physical properties of neoprene by comparing the following: predicted and actual values by inspection; the calculated % error of prediction; the squared multiple correlation coefficients; adjusted squared multiple correlation coefficients; the Fisher statistic and significance probability. Scheffe models do not have an intercept term and test statistics …

Flow Injection And Photometric Determination Of S(Iv) In Rainwater With Pararosaniline, Frank A. Hedgecock

Retrospective Theses and Dissertations

The photometric pararosaniline (pRA) method for determination of S(IV) has been adapted to flow injection sample processing (FIA). Prominent features of the method include a limit of detection of 0.010 ppm of dissolved sulfur dioxide and a sampling rate of 20 per hour. The concentration range investigated was 0.010 to 0.200 ppm S0₂. Sequential samples were collected from two rainstorms and SO₂ concentrations were measured for 19 samples. The suppression of interference by Cr(III), Mn(II), and Fe(III) using 1,2-cyclohexylenedinitrilotetraacetic acid (CDTA) and ethylenediaminetetraacetic acid (EDTA) was investigated. A comparison of the adapted FIA method and its parent …

New Synthetic Applications Of Enaminoketones, Timothy J. Buck

Retrospective Theses and Dissertations

This report discusses research concerning synthetic applications of enaminoketones. The work may be divided into four parts as follows: a) replacement of the dimethylamino group of certain enaminones by other amine groups through a simple procedure; b) formation of 3-alkyl-pyrazoles; c) formation of 2-amino-4-alkyl-pyrimidines; d) synthesis and subsequent reduction of iminium salts. The starting materials (E-1-(N,N-dimethylamino)-1-alkene-3-ones) have been condensed with hydrazine and guanidine to form pyrazoles and pyrimidines, respectively. The same starting materials have been reacted with POCl₃ in CH₂Cl₂ to produce chlorovinyliminium salts. These have then been reacted in situ with reducing agents to produce …