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We describe a new method for analysis of the nitrogen isotopic composition of sedimentary porphyrins. This method involves separation and purification of geoporphyrins from sediment samples using liquid chromatography and HPLC, oxidation of the nitrogen within porphyrin-enriched fractions using a two-step process, and isotopic analysis of the resulting nitrate using the denitrifier method. By analysis of these degradation products of chlorophylls, we are able to measure an isotopic signature that reflects the nitrogen utilized by primary producers. The high sensitivity of the denitrifier method allows measurement of small samples that contain low concentrations of porphyrins. Extraction of only 50 nmol of nitrogen (nmol N) allows the following five analyses to be made (each on ~10 nmol N): nitrogen concentration, an assessment of potential contamination by nonporphyrin N, and three replicate isotopic measurements. The measured values of [delta][sup.15]N have an average analytical precision of [+ or -] 0.5 [per thousand] (1 [sigma]) and an average contribution from Rayleigh fractionation of 0.7 [per thousand] from incomplete oxidation of porphyrin N to nitrate. The overall method will enable high-resolution records of [delta][sup.15]N values to be obtained for geological and ecological applications.

Research has been conducted on cobalt(II) porphyrins. The study of these compounds has been carried out in determining the role of distal site metalation and superstructure in dioxygen reactivity in cytochrome c oxidase's active site models, and the details are reported.

Research has been conducted on secoporphyrazines. The results of the photophysical evaluation and comparison of these compounds and their precursors are presented.

Research has been conducted on the deoxymyoglobin model (2-methylimidazole)(tetraphenylporphinato)iron(II). The preparation and characterization of this model are described and the results of the X-ray structure analysis indicate the presence of distortions in the iron coordination group and in the porphyrin core.

57Fe NMR spectroscopy is used in measuring porphyrin ruffling in hexacoordinated carbonmonoxy heme model compounds in solution. Ruffling occurs when opposite pyrrole rings are counterrotated so that the meso carbon atoms of each pyrrole ring are alternately displaced above and below the mean porphyrin plane. Results indicated good correlation between delta(57Fe) and the absolute crystallographic average displacement of the meso carbon atoms relative to the porphyrin core mean plane. It was also noted that 57Fe shieldings are excellent protocols in deriving precise structures of heme rings in heme model compounds.

A palladium crystalline sandwich-like porphyrin complex Sm(III)H(tpp)(oep) contains asymmetrical double decker oep and tpp rings. The oxidation state of the central Sm atom is 3+ and the coordination is square antiprism. In basic solvents the deprotonated form (Sm{III}{oep}{tpp})- is present and in CHCl2 the protonated form exists. This is the first X-ray single-crystal analysis of this kind of complex.

Research has been conducted on the sixth ligand effect. The authors describe the study of this effect in low-spin thiocarbonyl-ligated iron(II)octaethylporphyrinates carried out via the application of Mossbauer and infrared spectroscopies, and single-crystal X-ray structure determination.

Research has been conducted on octakis(phenylethyl)porphinato complexes of H (sub)2, Zn(II), Ni(II), Mg(II) and Cu(II) and their thimethylsilanylethynyl derivatives. The preparation of these complexes has been carried out, and the authors report that the X-structures of octakis(phenylethyl) compounds demonstrates deviation from Ni(II) as a function of the central cation.

Research has been conducted on oxophilic synthetic receptors. The authors have designed these receptors and carried out their synthesis via the use of porphyrin scaffold in order to construct the binding site for carbohydrates and phenols.

Research has been conducted on rhodium(III) porphyrin complexes. The authors describe the self-assembly and characterization of this complex via (super)1 H nuclear magnetic resonance spectroscopy, electron spray ionization-mass spectroscopy and infrared spetroscopy methods.

Research has been conducted on meso-tetraaryl cofacial bisporphyrins. The authors describe the use of Suzuki methodology in modular preparation of these compounds anchored by dibenzofuran and xanthene.

Research has been conducted on 10,20-diphenyl-5,15-bis(4-cyanophenyl)porphyrin. The synthesis of this compound and its reduction to produce 10,20-diphenyl-5,15-bis(4-formylphenyl)porphyrin are described.

Research has been conducted on beta-trifluoromethyl-meso-tetraphenylporphyrins. The study of electronic and steric role of trifluoromethyl group in macrocycle has been carried out via the synthesis of these tetraphenylporphyrins, and the results are reported.

Research has been conducted on triisopropylsilyl propynal. The authors report that boron trifluoride-catalyzed Rothemund condensation of this compound with 3,4-diethylpyrrole in dichloromethane produce chromophores with special spectroscopic characteristics.