Tetraphenylporphine (TPP) and its para-methyl derivative have been synthesized by direct reaction of pyrrole with the corresponding aldehyde. The synthesis of two unsymmetrically substituted tetraarylporphyrins is reported. The compounds prepared are' 5-(4-hydroxypheny1) -10,15,20-tritolyIporphyrin and 5-(4-hydroxypheny1)-10, 15,20-triphenyIporphyrin. The sy thesis of covalently linked porphyrin dimers, joined via ether linkages, is described. High yields of the tetraaryIporphyrin dimers were obtained by the reaction of the bi-functional1,6-ditosyloxyhexane with phenolic porphyrins such as 5-(4-hydroxypheny1)-10,15,20-tritoly1-porphyrin. The dimeric porphyrins were then chromatographically separated from the unreacted monomericLporphyrins. The reduction of the porphyrins(monomers and dimers) has been carried out using the standard diimide precursor, p-toluenesulfonylhydrazine. We have been able to demonstrate that the most efficient chlorin preparation involves the diimide reduction of a tetraaryIporphyrin to the corresponding bacteriochlorin, followed by the addition of the "high potential quinone" DDQ, to dehydro-genate the bacteriochlorin. A detailed study of the absorption spectra of these chlorins and bacteriochlorins was undertaken. Zinc metallo-derivatives of the porphyrins, chlorins and bacteriochlorins were prepared by the reaction of the free bases with zinc acetate in dry pyridine. An attempt was made to synthesize tetra-meso-[p, p ' - ( 3, 3 '-phenoxypropoxypheny1)]-strati-bis porphyrin (Compound XX), a novel cyclophane system composed of two opposed, co-axial porphyrin rings, rigidly held together by peripheral ether linkages. The synthesis was attempted by construction of a second porphyrin ring on top of a pre-existing one, by way of the condensation of four pyrroles with a tetraaldehyde, derivative of tetraphenyl-porphyrin, under high dilution conditions. The last reaction step was unsuccessful. The structures and purity of the intermediate compounds leading to the strati-bis-porphyrin were established by mass spectroscopy and proton n.m.r. spectroscopy. / Science, Faculty of / Chemistry, Department of / Unknown

The interactions between porphyrins and related tetrapyrrolic macrocycles play many varied and important biological functions. In many of these systems the tetrapyrrolic macrocycles, whilst not covalently linked, are closely associated and the proximity and relative orientations are of critical importance. This thesis describes the synthesis of a covalently bislinked dimeric porphyrin. Our approach consists of constructing a single link first, and building a porphyrin onto either end, simultaneously, in symmetrical fashion via an a,c-biladiene. A variety of methenes were produced to enable the synthesis of porphyrins with reactive side-chains diagonally opposed to the first link. Singly linked porphyrins with C₆, C₈ and C₁₀ chains were produced. The porphyrin side chains were then modified to produce a terminal acetylene diagonally opposed to the first link. The second link was then achieved by an oxidative coupling and catalytic hydrogenation to yield a bislinked porphyrin dimer with two hydrocarbon chains. A model reaction is also described in which a mono-meric porphyrin was dimerised to assess the feasibility of the side chain modification and the final oxidative coupling reaction to produce the singly linked dimer. / Science, Faculty of / Chemistry, Department of / Graduate

This study describes the partial synthesis of porphyrin SA11 (la) from protoporphyrin IX DME (32). Conversion of 2-(2-hydroxyethyl)-A-(2-methoxycarbonylvinyl)-deuteroporphyrin IX DME (Alb) into hardero-porphyrin (3Aa) is also outlined. Photo-oxidation of (32) gives the isomeric photoprotoporphyrins (36a) and (36b); these isomers can be separated by column chromatography. Compounds (36a) and (36b) are transformed into the mono-formyl-mono-vinyl-deuteroporphyrins (33a) and (33b) by reduction with borohydride followed by the cleavage of the resulting glycols with periodate. Treatment of (33a) and (33b) with 2 equivalents of thallium(III) nitrate in methanol affords the mono-acetal-mono-formyl derivatives which, on condensation with malonic acid in the presence of piperidine gives the mono-acetal-mono-acrylie acid-deuteroporphyrins. The mono-acetal-mono-acrylic acid derivatives are converted into the corresponding mono-acrylic acid mono-(2-hydroxyethyl)-deuteroporphyrins (Ala) and (Alb) by hydrolysis and reduction with borohydride. Treatment of (Ala) with CBr^/Ph-jP affords the 2-bromoethyl derivative (A2a) which, is converted into the corresponding 2-cyanoethyl derivative (A3) by cyanide in 1-methylpyrrolidone. Compound (A3) is transformed into porphyrin SA11 (la) by methanolysis. Hydrogenation of the acrylic acid side-chain of compound (Alb) followed by the dehydration of the 2-hydroxyethyl side-chain effect's the conversion of compound (A5) into harderoporphyrin (3Aa). / Science, Faculty of / Chemistry, Department of / Graduate

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Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Jonathan L. Sessler. Vita. Includes bibliographical references.

Porphyrins and viologens are often utilized in photocatalyzed electron transfer chemistry. Some of the problems faced by researchers in these applied studies include the lack of information correlating the porphyrin absorbance spectral changes with porphyrin dimerization, complexation, and the effect of noncomplexing cations. In addition, the efficiency of the system is greatly reduced by the formation of porphyrin:viologen association complexes. Knowledge of the values of these constants may allow selection of appropriate porphyrin:viologen concentration ratios which would enable optimization of these systems when used in such applications as artificial photosynthesis. This study reports the effect of selected salts and solvents on the porphyrin spectrum and the spectrum of the H₂TCPP⁴⁻ dimer. Moreover, we define experimental conditions appropriate to the study of porphyrin:viologen association and report association constants calculated at both constant ionic strength and constant buffer concentration. The spectrophotometric titration of tetrakis(pcarboxyphenyl) porphine (H₂TCPP⁴⁻) with either methyl viologen (MV²⁺) or propylviologen sulfonate (PVS⁰) results in the formation of H₂TCPP⁴⁻ :viologen complexes with stoichiometries of both 1:1 and 1:2. In addition, at high viologen concentration, PVS⁰ induces H₂TCPP⁴⁻ dimerization. Association constants for the titration of H₂TCPP⁴⁻ with MV²⁺ were calculated using data obtained at constant ionic strength (I = 0.15, maintained with KH₂P0₄/NaKHP0₄) and at constant buffer concentration ([KH₂P0₄/NaKHP0₄] = 5 mM) using both nonlinear least-squares (NLLS) and principal component analysis (PCA). At constant buffer concentration the association constants calculated via NLLS analysis and PCA were found to be, respectively, 3,170 and 3,350 for the 1:1 complex and 100 and 68 for the 2:1 complex. At constant ionic strength the association constants were calculated by NLLS to be 594 for the 1:1 complex and 38 for the 2:1 complex. PCA was used to confirm our model of the solution equilibrium equations used to calculate the association constants by NLLS analysis. In addition, this method yields the spectral line shape and absorptivity of the spectroscopically unresolved 1:1 H₂TCPP⁴⁻:MV²⁺ complex. From this information it was learned that both the absorptivity and the wavelength dependence of H₂TCPP⁴⁻ and the viologen complexes of H₂TCPP⁴⁻ were a function of the alkali metal cation concentration (higher concentrations of cations result in progressively weakened and blue-shifted spectra). Finally, we will present data which support the conclusion of Firman et al. that the spectrum of the H₂TCPP⁴⁻ dimer is weakened and blueshifted by approximately 10 nm relative to the porphyrin monomer in aqueous solution. We will further show that some organic ions induce H₂TCPP⁴⁻ dimerization and some do not; moreover, we will present experimental evidence demonstrating that the data cannot be explained as a simple effect of the ionic strength.

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Thesis (M.Sc.)--York University, 2003. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references (leaves 88-91). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ99270