Diels-Alder [4+2] cycloaddition of a mixture of 1- and 2 methylcyclopentadiene to 2-phenyl-g.-benzoquinone affords a mixture of four nd cycloadducts. A single, isomerically pure cycloadduct was isolated by careful column chromatography. Stereospecific reduction of this material with sodium borohydride and cerium(III) chloride 'affords a single, isomerically pure tricyclic diol. The structures of the cycloadduct and this tricyclic diol, established via analysis of their one- and two-dimensionial NMR spectra, were shown to be (1-methyl-5-phenyltricyclo[6.2.1.02,7]undec a-4,9 diene-3,6-dione and 1-methyl-5-phenyltricyclo[6.2.1.0 2 ,7 ]undeca-4,9-diene t.&A-3-=.a-6-diol), respectively. Intramolecular [2+2] photocyclization of this tricyclic diol afforded the corresponding cage diol, 3-methyl-7phenylpentacyclo[5.4.0.0 2 ,6 .03 , 1 0 .05, 9 ]undecane-.exogxa-8,11-diol. Oxidation of this cage diol with pyridinium chlorochromate in dry dichloromethane afforded a single, isomerically pure cage hydroxyketone, 3-methyl-7 phenylpentacyclo[5.4.02,6.03,l .1519]undecane-xA-8-ol-II-one, whose structure was established by single crystal X-ray crystallographic methods.

Small weight percentages of certain high-molecular weight polymers added to liquids in turbulent flow through conduits can result in dramatic friction reduction. Although many current and potential uses of the drag reduction phenomenon exist, there is a fundamental problem: drag reduction efficacy decreases rapidly with flow time due to the mechanical degradation in flow of the added polymer. In this thesis study, dilute aqueous solutions of polyacrylamide were tested under turbulent flow conditions in an attempt to determine where mechanical degradation in flow occurs.

The growth of strontium sulfate precipitate by diffusion in various gels was studied by using optical transmission and confocal microscopies, scanning and transmission electron microscopies, and energy dispersive X ray fluorescence. Pure silica gel, pure agarose gel and the silica/agarose mixed gel at pH 7 - 10 were used throughout the present study. Precipitate morphology is sensitive to pH and to the nature of the growth medium. The morphology was observed as a function of time. The lack of change is presumably because of rapid depletion of the limiting reagent after the very beginning of precipitation. The problem of separating strontium sulfate precipitate from the gel medium is discussed.

The thermocyclic fatigue behavior of the low-melting solder 43Sn/43Pb/14Bi has been investigated and compared to that of standard 60Sn/4OPb solder via metallographic analysis (using scanning electron microscopy) and evaluation of the degree of fatigue development (using a fatigue scale as a function of thermocycles). Specimens were subjected to shearing strains imposed by several hundred fatigue thermocycles. Both solder types fatigue by the same microstructural failure mechanism as described by other workers. The mechanism is characterized by a preferential coarsening of the solder joint microstructure at the region of maximum stress concentration where cracks originate.

The kinetics of ligand substitution for CO in Co4(CO)10(mu4-PPh2) , 1, have been investigated for the ligands P(OMe)3, P(OEt)3, PPh2H, P(0-i-Pr)3, P(n-Bu)3, PPh3, P(i-Pr)3, and PCy3 over a wide temperature range.

Molecular rotational motions are known to influence both Raman scattering of light and nuclear spin relaxation. Therefore, the application of Raman bandshape analysis and NMR relaxation time measurements to probe molecular dynamics in liquids will provide us with a deeper understanding of the dynamical behavior and structure of molecules in the liquid phase. Presented here are (i) studies of molecular reorientation of acetonitrile in the neat liquid phase and in solution by Raman bandshape analysis and NMR relaxation; (ii) studies of reorientational dynamics and internal rotation in transition metal clusters by NMR relaxation.

1,1-Dimethyl-2-neopentylsilene reacted with the N-methylimine of benzophenone to give 1,2,2-trimethyl-3- neopentyl-4,4-diphenyl-l-aza-2-silacyclobutane, I, and 2,3,4,4a-tetrahydro-2,3,3-trimethyl-1-phenyl-4-neopentyl-2- aza-3-silanephthalene, II, in 35% and 20% yields, respectively. Compounds I and II did not serve as thermal silene precursors. Heating I and II to over 280°C did not yield 1,3-disilacyclobutanes. In the presence of 2,3- dimethyl-1,3-butadiene typical silene products were not obtained. However, I and II reacted rapidly with methanol at room temperature to give the ring-opened products (E)-2- methoxy-2,5,5-trimethyl-2-silahex-3-ene, III, 1,1- diphenyldimethylamine, IV, and 2-methoxy-2,5,5-trimethyl-3- (N-methylaminodiphenyl) methyl-2-silahexane, V.