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The synthesis, characterization, and electrochemical studies of [beta],[beta]'-fused metallocenoporphyrins are described. The novel Pd(0) catalyzed [3@] cycloaddition reaction with porphyrins was studied, a series of [beta][beta]' fused monoruthenoceno metalloporphyrins and bismetalloporphyrins with different central metals were prepared and significant electronic interactions between the metallocene and metalloporphyrin were observed.

A study was conducted to investigate in detail the [super 1]H NMR spectra of the ferriheme center and nearby protein residues in the high- and low-spin forms of the nitrophorins (NPs) from Rhodnius prolixus. The structures of the ferriheme complexes in terms of the orientation of the histidine imidazole ligand orientations depends on the heme cavity shape and could be altered by mutation of amino acids with side chains (phenyl vs tyrosyl) near the potential position where a heme vinyl group would be in one of the isomers.

Research has been conducted on nickel(II) porphyrins. The electrochemistry of these compounds has been investigated in the effort to understand the effect of structural and electronic factors on electron-transfer processes in porphyrins, and the details are reported.

Research describes synthesis of a new series of heterobimetallic cofacial diporphyrins containing luminescent Ga(III) centers. The reduction of dioxygen by cofacial cobalt(II) diporphyrins is studied by photophysical and spectroscopic methods.

Research has been conducted on the dissociation of PH (sub)3 from the 18-electron system CpMoX(PH (sub)3) (sub)3. The use of the density functional theory is examined.

A study was conducted to examine the effects of the symmetry of substitution pattern and substituent orientations on the out-plane and in-plane distortions of the macrocyle of nickel porphyrins. These nickel porphyrins were analyzed through the use of molecular mechanics calculations, X-ray crystallography, UV visible absorption spectroscopy and resonance Raman spectroscopy. Results revealed that out-plane and in-plane distortions were dependent on perturbation symmetry of the peripheral substituents.

Research was conducted to study the influence of central metals of various sizes on the macrocyclic structure of a series of 5,15-disubstituted metallophorphyrins. Methodologies used included X-ray crystallography, resonance Raman spectroscopy and molecular mechanics. The contributions of the ruf and dom deformations in the crystal structures of several metal complexes of the phorphyrins were found to be metal-dependent. Results indicate the quantitative validity of normal-coordinate structural decomposition.

The synthesis and characterization of a series of monometallo-, bimetallo-, and heterobimetallo-1,2-ethene-linked cofacial bisporphyrins are presented. Two heterobimetallic cofacial bisporphyrins were synthesized easily by initially forming monometalated species with subsequent insertion of a second metal ion. Initial monometalations were observed to be slower under dilute conditions in CH2Cl2/MeOH at refluc but under dilute conditions in hot DMF, the insertion rate was sufficiently fast to enable isolation of the monometalated cofacial isomers as the major product.

An experiment was conducted to examine the electrochemistry and ozonation reactions of manganese (III) dodecaphenylporphyrins compounds and their derivatives. Nuclear magnetic resonance (NMR) and UV-visible spectra were performed on the compounds using UV and NMR spectroscopy. Results showed that each (P)MnCl derivative can exist in five different oxidation states and that all compounds are stable in their neutral form and even during the addition of three electrons.

X-ray crystallography and proton nuclear magnetic resonance spectroscopy were done to determine the structure of symmetrically and asymmetrically highly substituted porphyrins. The results showed that the decasubstituted free-base porphyrins with two meso-aryl substituents have a negligible out-of-plane distortion but a large amount of in-plane distortion, with the corresponding nickel(II) complexes having either planar or modestly nonplanar arrangements. The nickel(II) complexes of 5,15-diethyl-substituted porphyrins, on the other hand, were found to have very ruffled conformations, in spite of the planar arrangement of the corresponding free-base porphyrins.

Proton NMR spectroscopic and molecular mechanic studies of seven dodecasubstituted porphyrins reveal that these compounds possess identical structures in both solution and solid states, implying the presence of cavities in solution also. The compounds with these cavities react with 1,3,5-trinitrobenzene to result in pi-complexes and find application as oxidation catalysts with good optical selectivity. The presence of the cavities modifies the physical and chemical properties of the porphyrins.

A single-step reductive coupling of metal(II) 5-formyloctaethylporphyrins produces both cis-1,2- and trans-1,2-ethene-bridged bisporphyrins. Pi-pi aggregation of the monomeric subunits is significant in the formation of cis-ethene-bridged bisporphyrins. Crystal structures of the cis-dimer exhibit both intra- and intermolecular aggregation and the cis-dimers having cofacial bisporphyrins have significant overlap of the pi-system. X-ray and spectroscopic studies help determine the molecular structures of 1, 1-carbinol-bridged bisporphyrins and the trans-1,2-ethene-bridged bisporphyrin.

Electronic absorption and magnetic circular dichroism (MCD) spectroscopic experiments help characterize iron methylchlorin- and mesochlorin-reconstituted myoglobin, horseradish peroxidase and cytochrome b5. A comparative study of these spectra with those of corresponding iron octaethylchlorin complexes helps derive spectral signatures for histidine-ligated iron chlorin-containing proteins. MCD spectroscopy is an efficient technique to determine iron chlorin coordination structure, spin state and oxidation state, and to differentiate two types of green heme systems, iron-chlorins and iron formyl-substituted porphyrins.

MCD spectroscopic studies of the electronic structures and coordination behaviors of three nickel porphyrins that have different patterns and amounts of macrocycle deformations reveals A-term peaks for all three compounds, indicating that both ruffled and saddle-shaped conformations retain D(2d) symmetry. MCD spectra of Ni(II) protoporphyrin IX-reconstituted hemoglobin ((Ni)Hb) and myoglobin ((Ni)Mb) reveal that protein does not influence the energy level of nickel porphyrins.

X-ray studies of 3,5,7,13,15,17-hexaethyl-2,8,12,18-tetramethylporphyrin (H2DAP) crystals reveal an elongated planar macrocycle along the 5,15 axis that cancels the steric interference of the meso and pyrrole ethyl groups. Another decaalkylporphyrin NiDAP, reveals nonplanar distortion in the porphyrin unit to relieve steric crowding. Optical spectroscopy, NMR and MO calculations help examine solution conformations of H2DAP and NiDAP. Low-temperature NMR studies reveal cis and trans conformation of the methyl groups of the meso ethyls in H2DAP and ZnDAP.

The aggregation properties of a series of 5-nitro derivatives of octaethylporphyrine were investigated. Results showed that strong pi-pi dimeric or linear aggregates of nitro-substituted metalloporphyrins were observed in the solid state. Analysis of several porphyrin molecules showed a requirement for an asymmetric electron distribution in the system. Weak aggregation was observed in the free-base porphyrin while intermediate to strong dimerization was shown by corresponding zinc complexes.

The nickel and copper complexes of dodecasubstituted porphyrins bearing aryl groups at the meso positions and propano rings at the pyrrole beta positions were investigated. It was shown that the nickel complex NiTC5T(3,4,5-OMeP)P exhibits a nonplanar conformation, while the corresponding copper complex CuTC5T(3,4,5-OMeP)P is planar. The usefulness of spectroscopic probes of porphyrin nonplanarity is also investigated. The identification of the planar dodecasubstituted porphyrin indicates the flexibility of the tetrapyrrole macrocycle.

The magnetic circular dichroism (MCD) spectra of five- and six- coordinate chlorin complexes with nitrogenous axial ligands to ferric and ferrous ions are studied. The complexes examined are bis(1-methylimidazole)ferrous, (1,2-dimethylimidazole)ferrous, bis(1-methylimidazole)ferric and 1-methylimidazole/CO or NO compounds. The results show unique MCD signals for determining the presence of histidine or axial ligands in iron chlorine-containing protein.

The structures of two bacteriochlorophyll c and one bacteriochlorophyll d related to the bacteriochlorophylls of Chlorobiaceae and Chloroflexaceae are determined. The three compounds show S4-ruffling effect common in Ni(II) porphyrins and all have four alternating meso-carbons above and below the nitrogen plane and out-of-plant rotations of the pyrrole rings. The deviations from the least-squares plane of the four nitrogen atoms in all the compounds revealed a localized distortion at the methyl substituent at C(20) position.

The nitro-substituted silver(III) corrole obtained by reaction of corrole with AgN[O.sub.2] is studied using cyclic voltammetry and spectroelectrochemistry.The [pi]-cation radical of the complex acts as the reaction intermediate which is attacked by the nitrite ion.

The ferriheme resonances of low-spin nitrophorins (NP) 1 and 4 were assigned and compared to those of NP2 by using NMR spectroscopy. The effective nodal plane of low-spin NP1, NP4, and NP2 complexes in all cases of imidazole and histamine complexes is found to be quite similar to the average of the His-59 or -57 and the exogenous ligand angles seen in the X-ray crystal structures.

Three metallo-benzoylbiliverdins are synthesized in 60%-87% yields from oxidation of dodeca-substituted porphyrins with NaNO2/TFA and air or by reaction with mCPBA/pyridine and air. The X-ray structures of two of the complexes and the electrochemistry of the three metallo-benzoylbiliverdins are discussed.

Research has been conducted on aryl-porphyrin rotational barrier. The authors have used NMR spectroscopy in examining the relationship between this barrier and the core substituent M in some octaphenylporphyrins.

A nonaqueous medium is used to reveal three reversible one-electron oxidations which influence a Ni(II) porphyrin or porphyrene to form (P)Ni and (OEPc) Ni. A Pi cation radical and dication are produced in a systematic method to coordinate with the primary two oxidations. A Ni(II/III) interaction is observed at half-wave potentials during the third oxidation. The Fe(II) and CO(II) complexes show metal-centered oxidations with TPP, OEPc or ORTPP macrocycles, with half-wave potentials that are compared to the Ni(II) porphyrins.