In an effort to determine if there is a specific conformational structure which is most effective at the appropriate active physiological site, the synthesis of a group of sterically restricted analogs was undertaken. A portion of the polymethylene carbon skeleton of glutaric acid was replaced by selected aromatic carbons in benzenedicarboxylic acids to produce a series of ridged conformers, and the relative plant growth regulating properties of these derivatives were determined.

The kinetics and mechanism of the reactions of (tmpa)W-(CO)^ and (tmen)W(CO)^ (tmpa = N,N,N',N'-tetramethy1-1,3-diaminopropane and tmen = N,N,N1,N1-tetramethylethylenediamine) with four phosphorus donor ligands (triisopropyl phosphite, triphenyl phosphite, triphenylphosphine and "constrained phosphite", 4-methyl-2,6,7-trioxa-l-phosphabicylo[2.2.2]octane) in xylene have been investigated in detail. These reactions were found to take place by the ring-opening of the bidentate ligand in a reversible step which leads to the formation of a five-coordinate intermediate of the type [(h^-tmpa)W(CO)or [(h^-tmen)W(CO). The intermediate then reacts with one molecule of phosphorus ligand, L, to form a six-coordinate intermediate, which can either expel the bidentate ligand and react with another molecule of L leading to the formation of a new disubstituted tungsten tetracarbonyl or go through a ring-reclosure step to form a seven-coordinate activated com-2 2plex or intermediate of the type [(h -tmpa)W(CO)^(L)] or [(h - tmen)W(CO)^(L)] which then regenerates the substrate through the expulstion of the L molecule. This mechanism is consistent with the observed rate behavior in these systems. For the reaction of (tmpa)W(CO)^ with the "constrained phosphite", an intermediate of the type [(h1-tmpa)W(CO)4P(OCH2)3CCH3] was isolated and identified.

The purpose of this investigation is to study the Birch reduction products of [2.2lparacyclophane and of [2.2]paracyclophane- 2-carboxylic acid. The tetrahydro Birch reduction product of [2.2]paracyclophane is shown to be dl stereoisomer, with the olefins of the upper deck only partially overlapping with the olefins of the lower deck. This stereochemical elucidation is accomplished by means of a complete proton nmr analysis of the tetraepoxide derivative. A proposed mechanism supported by VB (valence bond) and MO (molecular orbital) theories for this Birch reduction process is presented.

The central nature of nicotinamide in metabolic processes as a part of the NAD and NADP coenzyme systems prompted the synthesis of a series of N-nicotinyl- and N-isonicotinyl-N'- (substituted)ureas as potential metabolite antagonists of the vitamin. The compounds which were synthesized may be represented by the following general structure, where R = hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-hexyl, cyclohexyl, phenyl and a-naphthyl. The observed toxicity of the N-nicotinyl-N'-(substituted)urea analogs may be attributed to the formation of a non-functional N-nicotinyl-N'-(substituted)urea-NAD analog through an exchange reaction catalyzed by NAD-ases in the cell. Support for this view was obtained by an in vitro enzymic synthesis of Nnicotinyl- N'-ethylurea-NAD analog employing N-nicotinyl-7- 1 4CN'- ethylurea. The labeled derivative was characterized through spectral, chromatographic, and chemical reaction studies.

The principle objective of this study is to conduct a definitive investigation into the cycloaddition of allenes and ketenes, with particular emphasis on halogenated ketenes.

It was proposed to study the cycloaddition of ketenes and carbodiimides in some detail. The first objective was to investigate the general applicability of the reaction as a tool for the synthetic organic chemist in the preparation of a new class of substituted β-lactams; i.e., imino-β-lactams. It was proposed for this part of the research problem to look for the intermediate, either directly or indirectly, by trapping experiments. It was further proposed to study substituent effects in the ketene and carbodiimide and also Investigate the effect of solvent polarity on the reaction rate. From these data, it was hoped that the mechanism of the cycloaddition reaction could be elucidated.

With three different proposals for the bonding in metal carbonyls, it was decided to look into the situation more thoroughly in order to see what other evidence was available to support or refute any of these ideas. It became obvious that a definite contradiction existed between the kinetic evidence of various metal carbonyls, and the concept of MC bond strengths as predicted by Cotton's theory.

The problem with which this investigation is concerned is twofold. The initial part of the problem was to prepare a non-sterically demanding bidentate phosphine ligand, 1,2-bis-(Phosphino)ethane, (P-en), and to determine the kinetics of (P-en)Mo(CO)4 with phosphites via spectrophotometric methods in an attempt to determine if steric effects are directing the type of mechanism followed.

The recombination rate coefficient for molecular helium ions has been measured in a pulsed afterglow at 1.86 Torr as a function of electron temperature and electron density without making a priori assumptions about the functional dependence. The concentrations of the molecular ions and electrons were measured and the source terms for the molecular ions were included in the rate equation.

The synthesis and characterization of two new Schiff base copper(II) complexes are reported. These are Cu(acac: 2-amino-l-phenylethanol) and Cu(acac:2-amino-l-butanol). The ligands, derived from acetylacetone and the appropriate aminoalcohol, are dibasic tridentates with 0,N,O donor atoms. The magnetic properties of the complexes were studied at several temperatures between 78 OK and 296 OK. The magnetic moment of Cu(acac:2-amino-l-phenylethanol) varied little with temperature, and that of Cu(acac:2-amino-lbutanol) increased as the temperature was lowered. This is in contrast to the magnetic moment of Cu(acac:ethanolamine), which decreases as the temperature decreases. Molecular weight data, infrared spectra, magnetic data, electronic spectra, and electron spin resonance spectra of both complexes are reported and discussed.

The initial purpose of this study was to determine if steric problems would account for the difference in the products obtained in the reaction of the N-(substituted)phthalimide with low and high molecular weight amines.

A model system to calculate single-path coupling constant was devised to see if the couplings are additive in a system which has a dual-pathway. The system chosen was o-methyl-13C-benzoic acid. Because of anomalies in the data, the series was extended. Hybridization of the label appeared to have relatively little effect, and the conformation of the substituents very important.

The investigation presented here is in two parts: a mechanistic study of the triethylamine dehydrohalogenation of ac-haloacid halides to form halogenated ketenes and a study of steric influence upon ketene lifetimes. The first part of this research deals with the mechanism of the dehydrohalogenation reaction. Two acid halides, isobutyryl chloride and a-chloropropionyl chloride, appeared to represent two mechanistic extremes for this reaction with triethylamine. Isobutyryl chloride reacted with triethylamine to form an acylammonium salt while a-chloropropionyl chloride produced the enolate salt. These salts were detected in chloroform solution by both nuclear magnetic resonance spectra and infrared spectra. The results of the investigation into the mechanism of dehydrohalogenation and ketene lifetime were complemented by CNDO/2 calculations of the acid halides and ketenes studied. It was concluded that the mechanism of dehydrohalogenation of acid halides involves a complex series of equilibria,and it has become increasingly apparent that halogenated ketenes are produced through the acylammonium salt. The enolate salt appears to be a dead end in the reaction to form ketenes. It was also demonstrated that increasing steric bulk has a stabilizing effect on ketene lifetimes.