The structure of 1,2,3,4,5,6,7,8-octaethylporphyrin has been determined from three-dimensional X-ray data collected by counter methods. the compound crystallizes in the triclinic space group PI with one molecule in a unit cell of dimensions a = 9.791 (2) á, b = 10.771 (2) á, c = 7.483 (2) á, a = 97.43 (1)°, β = 106.85 (1)°, and γ = 93.25 (1)°. The observed and calculated densities are 1.19 (1) and 1.191 g cm-3, respectively. The structure was solved by the determination of the best orientation of a calculated porphyrin ring in an origin removed sharpened Patterson map. Least-squares refinement has led to a final value of the conventional R factor (on F) of 0.039 for the 2518 reflections having F2> 3σ-(F2). The structure consists of well separated molecules, each with a crystal-lographically imposed center of symmetry. The porphyrin macrocycle is essentially planar with two independent pyrrole rings which are significantly different from each other. The amino hydrogen atoms are located on one pair of nitrogen atoms. A comparison of this structure with those of meso-substituted porphyrins and porphine indicates that the structures are similar but that substituent groups on the macrocycle cause changes in geometry closest to the point of substitution.
ASJC Scopus subject areas
- Colloid and Surface Chemistry