Aggregation of 2,3-dihydroxy-etiochlorin I. An amphiphilic model compound for photodynamic therapy and green heme d.

The crystal structure of 2,3-dihydroxy-etiochlorin I has been determined to obtain information on its aggregation behavior. Cis-dihydroxychlorins serve as model compounds for green heme d and show promising photonecrotic activity in photodynamic therapy. The compound shows strong aggregation in the solid state facilitated by intramolecular hydrogen bonding between one hydroxy group and pyrrole nitrogens of neighboring molecules. This novel type of aggregation leads to chain-type aggregates in the crystal. The title compound 4 crystallized in the monoclinic space group Ia (Z = 4) with unit cell dimensions a = 9.902(4) A, b = 26.430(9) A, c = 10.823(5), beta = 104.47(3) A, V = 2743(2) A3. The structure was refined to an R-value of 0.097 on the basis of 1150 reflections with F > 4.0 sigma (F) (130 K).

Origins of etioporphyrins in sediments: evidence from stable carbon isotopes.

In samples of the Julia Creek and Condor oil shales (Australia, Albian, and early Tertiary, respectively) etioporphyrin III is significantly depleted in 13C (4%) relative to porphyrins derived from chlorophylls. This isotopic difference suggests a large contribution from some independent source. The haem group found in cytochromes derived from microbial sources is the most likely candidate.