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This research has been directed at the study of organosulfur frontier orbital interactions with transition metal d-orbitals. Two novel thioether complexes tricarbonyl(1,4,7-trithiacyclononane)molybdenum(O) and tricarbonyl(2,5,8-trithianonane)molybdenum(O), have been prepared and structurally characterized by single crystal x-ray crystallography. The facial configuration of the carbonyl ligands provides a unique point of reference for describing the two polythioether ligands in terms of the free ligand's frontier orbitals. The relative carbonyl stretching frequencies of the two metal complexes indicate that 1,4,7-trithiacyclononane is a poorer donor than 2,5,8-trithianonane. This result is explained in terms of mechanical constraints placed on the mesocyclic polythioether which are absent in its acyclic analogue. The coordinatively unsaturated species (n⁵-C₅H₅)MO(NO)(SC₆H₅)₂ has been characterized by x-ray crystallography and its electronic structure has been modeled using Fenske-Hall molecular orbital calculations. The monomeric nature and chemical inertness of (n⁵-C₅H₅)MO(NO)(SC₆H₅)₂ are attributed to dπ-pπ bonding between the thiolate ligands and an empty molybdenum dπ orbital. The dπ-pπ interaction simultaneously strengthens the metal thiolate bond and makes the complex less susceptible to nucleophilic attack by raising the energy of the LUMO. The rotational orientations of the thiolate ligands observed in the solid state support this electronic model. For (n⁵-C₅H₅)Fe(CO)₂SR, the dπ-pπI antibonding interaction between the thiolate ligand and the metal has been modeled using Fenske-Hall molecular orbital calculations and experimentally investigated by photoelectron spectroscopy. The calculations predict that the HOMO is metal-sulfurn-antibonding and largely sulfur 3p in character. The observed HOMO ionization energies of (n⁵-C₅H₅)Fe(CO)₂SC₆H₄-p-Z; Z = OMe, H, Cl, CF₃, N0₂; correlate with several chemical properties including the rate of electrophilic attack on the sulfur by alkyl halides to give the thioether complex [(n⁵-C₅H₅)Fe(CO)₂(SR₂)]X and by electron-deficient alkynes to give the heterometallacycle (n⁵-C₅H₅)(CO)FeS(R)-C=C=C=0. The latter reaction is compared to the similar reaction of alkenes and alkynes with (n⁵-C₅H₅)Fe(CO)₂PR₂ to give (n⁵-C₅H₅)(CO)FeP(R)₂-C=C-C=0. X-ray crystal structures of one of the sulfur-containing and one of the phosphorus-containing heterometallacycles have been obtained.

With n-BuLi/t-BuOK (Lochmann's base), protons are removed from the hydroxyl and methyl groups of cresols to give cresol dianions in yields of 85% (o), 95% (m), and 40% (p). These dianions react with alkyl halides, MeSiCl, Bu₃Sn Cl, CO₂, and oxidizing agents at carbon only, and with dialkyl sulfates at both carbon and oxygen. Thus phenol derivatives bearing primary alkyl groups can be prepared from the corresponding methylphenol via cresol dianions. Dimethylphenol trianions were prepared with Lochmann's base from all six isomers of dimethylphenol. 3,5-Dimethylphenol trianion was prepared in the best yield (80%); 2,3-, 2,4-, 2,5-, 2,6-, and 3,4-dimethylphenol trianions were prepared in 19.5%, 19%, 52%, 36%, and 44% yields, respectively. The common side products were dianions and tetraanions (in the latter, the fourth proton was usually pulled from the ring ortho to oxygen). These trianions were reacted with dimethyl sulfate to give anisole derivatives. 3,5-Dimethoxytoluene monoanion was reacted with n-BuBr to give a mixture of O,O'-dimethylolivetol (40%) and 4-butyl-3,5-dimethoxytoluene (34%).

Bis-benzyl dianions were prepared from the three symmetrical dimethylbiphenyls in yields of 79-86%, and shown to react with a variety of electrophiles on the benzylic carbons. Electrophiles included dimethyl and diethyl sulfate, isopropyl bromide, t-butyl iodide, allyl chloride, trimethylsilyl chloride, trimethylgermyl bromide, and trimethyltin chloride. Reaction of the dianions with (alpha),(omega)-dihalides provides an excellent route to n.0 - and n.0.n.0 cyclophanes. An X-ray study on 14.0 paracyclophane showed it to have a conformation different from that observed in solution by NMR; MM2 calculations were used in determining what the solution conformation is likely to be. Oxidation of the dianions produced the monomer dihydrophenanthrene from the ortho isomer, dimer 2.0.2.0 metacyclophane from the meta isomer, and polymer from the para isomer. An X-ray study on 2.0.2.0 metacyclophane showed it to have the same conformation in the crystal as is observed in solution by NMR. An NMR method for determining the angle of twist in a biphenyl based on the chemical shift of the ortho hydrogens was developed. Many oxidizing agents were evaluated for the oxidation of the dianion from 2,3-dimethyl-1,3-butadiene to 1,2,5,6-tetramethylenecyclooctane; cupric bromide was found to be the best.

The excited state emissions and lifetimes of [Cr(bipy)₃]³⁺, cis – [Cr(bipy)₂Cl₂]⁺, trans – [Cr(py)₄FBr]⁺, cis – [Cr(phen)₂F₂]⁺, and trans – [Cr(py)₄F₂]⁺ were studied in hydroxylic and nonhydroxylic solvents at 77 K and as a function of temperature. The emission characteristics are determined by the relative disposition of ²E and one component of ²T₁. The energy of these two levels is influenced by intramolecular and environmental factors, and solvent-induced level inversion occurs in cis – [Cr(phen)₂F₂]⁺. The influence of temperature and solvent viscosity were studied in several glasses with variable melting ranges. The emission of all of the complexes, except [Cr(bipy)₃]³₊, were found to be influenced by solvent viscosity. This influence is large when ²E and the component of ²T₁ are close in energy, and level inversion upon melting of the solvent occurs in cis –[Cr(phen)₂F₂]⁺. The decay of the emission of Cr(III) complexes normally shows small temperature dependence at lower temperatures and large temperature dependence at higher temperatures. The threshold for the appearance of strong temperature dependence depends on intramolecular and environmental factors. The decays of all the complexes except [Cr(bipy)₃]³⁺ show strong discontinuities in the rigid-fluid transition regions of the solvent glasses which are accompanied by risetimes in the decay profiles when the emission intensity is monitored at long wavelengths. This is attributed to solvent relaxation during the excited state lifetime.

The first part of this dissertation covers the microwave spectroscopy of the weakly bound complexes HI-HF, H₂S-SO₂, Ar-H₂S, and N₂O-HF. These molecules were investigated using a Flygare-Balle type pulsed-beam Fabry-Perot Fourier-transform microwave spectrometer. The spectrometer and its construction are described. The HI-HF complex was found to be hydrogen bonded through the hydrogen of the HF. The hydrogen bond length was found to be 2.720A with a structure such that the monomer bonds form an acute angle of 70°. For H₂S-SO₂ a structure with a S-S distance of 3.67A and H-O distances of 3.1A was obtained. It was established that the hydrogens of H₂S are equivalent is this species. A new set of transitions for Ar-HDS were observed indicating that the hydrogens in this molecule are not equivalent. Several new transitions were also observed for Ar-H₂³⁴S, Ar-H₂S and Ar-D₂S. New insight into the structure of the Ar-H₂S molecule was obtained. Several new transitions for the bent isomer of N₂O-HF were measured and a fit of the ground state constants for this species was performed including quartic distortion constants. The resulting fit improves calculated line centers by two orders of magnitude over previous results. The second part of this dissertation covers the infrared spectroscopy of the ν₆ and ν₈ bands of formic acid. Fourier transform data for these bands were obtained at 0.01 cm⁻¹ resolution using the spectrometer at the Kitt Peak National solar observatory. Diode laser data at 0.001 cm⁻¹ was obtained for the ν₈ band. A two state a-type Coriolis coupled Hamiltonian was used to perform a global fit on all the available data. A greatly improved set of spectroscopic parameters for these two bands were obtained. This new set of parameters has allowed several previously unassigned far I.R. laser and I.R. laser saturation lines to be assigned. Using these improved constants, it should be possible to predict the frequencies for several formic acid far I.R. laser transitions which are not yet accurately measured.

The photochemical fragmentation of Fp(η¹-CH₂C₆H₅) and Me₂Si[C₅H₄Fe(CO)₂(η¹- CH₂C₆H₅)]₂ (2) to give metal-metal bonded species and bibenzyl as products has been explored. Several singly-bridged binuclear iron complexes have been prepared, namely Me₂Si[η⁵-C₅H₄Fe(CO)(L)I]₂(L = CO; L = PPh₃; L = P(OPh)₃) and [η⁵-C₅H₅Fe(CO)I]₂[(PhO)₂PC₂H₄P(OPh)₂], and their structure explored by both spectroscopic means and X-ray analysis. The preparation of the new metal-metal bonded complex, [η⁵-C₅H₅Fe(CO)]₂[(PhO)₂PC₂H₄P(OPh)₂], is also reported. Selective alkylations and reductions of the diiodide were L = PPh₃ with n-BuLi, benzylmagnesium chloride, and LiAlH₄ have led to the preparation of mixed alkyl-iodide and alkyl-hydride compounds. Molecular and crystal structures are determined for Me₂Si[η⁵-C₅H₄Fe(CO)]₂[dppm], Me₂Si[η⁵-C₅H₄Fe(CO)]₂[dppp], and Me₂Si[(η⁵- C₅H₄)₂Fe₂(CO)₃][dppm]. Full details on the synthesis, characterization, and the electrochemistry of the binuclear complexes Me₂Si[η⁵-C₅H₄Fe(CO)]₂[L] (where L = dppm, dppe, dppp) is reported. Also complexes of the type Me₂Si[(η⁵-C₅H₄)₂Fe₂(CO)₃][L] have been isolated in the case of L = dppm and dppe. A series of tetranuclear complexes for L = dppe and dppp is presented. A variety of activated unsaturated compounds, including acrylonitrile, react with Fp(η¹- C₅H₅), where Fp = η⁵- C₅H₅Fe(CO)₂, to give [3+2]-cycloadducts in good yield. Stereospecific replacement of the Fp moiety in these cycloadducts by a -CO₂Me group with retention of configuration occurs in good yield by oxidation with ammonium cerium (IV) nitrate in carbon monoxide saturated methanol. This two-step sequence: (3+2)-cycloaddition followed by oxidation, renders Fp(η¹- C₅H₅) a synthetic equivalent of methyl 1,3-cyclopentadiene-5-carboxylate in cycloaddition reactions. Sequential reaction of η⁵-C₅Me₅Fe(CO)₂I with AgBF₄, cyclopentadiene, and finally triethylamine affords the new compound η⁵- C₅Me₅Fe(CO)₂(η¹- C₅H₅) in 75% yield. This complex has been characterized by X-ray diffraction and low temperature NMR spectroscopy.

In this study, synthetic routes to certain short acyl chain phospholipids were developed. Their inhibitory or substrate properties for phospholipase A₂ were then examined. An improved method for the acylation of glycerophosphocholine is described using a mixed fatty acid - trifluoroacetic acid anhydride. This partial synthetic route is particularly suitable for obtaining short acyl chain phosphatidylcholines. A new pathway for constructing the unnatural sn-1-phosphatidylcholines is also described, starting from L-arabinose. This is converted first to a key intermediate, 2,3-O-isopropylidene-sn-glycerol, which is then phosphorylated and transformed into sn-glycero-1-phosphocholine. This can be acylated as above to give sn-1-phosphatidylcholines. Routes to the short chain phosphatidylethanolamines were investigated and discussed. A procedure, using phospholipase D, was used to convert L-diC₆ PC into L-diC₆ PE in a transphosphatidylation reaction. Failed attempts to obtain shorter chain homologs by this and other methods are also detailed. The kinetics of inhibition of the phospholipase A₂ hydrolysis of L-diC₆ PC by the D-isomer are also reported for the monomeric concentration range. It was found that the D- enantiomer did not behave as a pure competitive inhibitor, and that an enzyme-substrate-inhibitor complex can exist. The implications of these results with regard to PLA₂ hydrolysis of mixed micelles is discussed. The PLA₂ substrate properties of both the anionic and zwitterionic diC₆ PE's were also studied. It was established that the anionic diC₆ PE is either a very poor substrate relative to the zwitterionic diC₆ PE, or acts as a competitive inhibitor towards its hydrolysis. Similarly, the rates of base-catalyzed acyl ester hydrolysis are about 18 times greater for the zwitterionic than for the anionic diC₆ PE. The importance of a protonated amino group in both these hydrolyses studies is noted. In addition, certain physical properties of diC₆ PE, such as its critical micelle concentration and carbon-13 NMR spectrum, are also given.