The structure of the free base porphyrin, mesoporphyrin IX dimethyl ester, has been determined from three-dimensional X-ray diffraction data. The porphyrin crystallizes with two molecules per unit cell in the triclinic space group Ci 1- [formula ommited] with a = 23.458 (8) Å, b = 11.378 (4) Å, c = 5.971 (2) Å, α = 93.25 (2)°, β = 94.23 (2)°, and γ = 93.82 (2)°. The structure has been refined anisotropically to a final unweighted R index (on F2) of 0.072 based on 5107 measured intensities. The R index (on F) for the 3336 reflections having Fo 2> 3σ(Fo 2) is 0.049. Bond lengths and bond angles within the porphyrin core have been determined to estimated standard deviations of ±0.003 Å and ±0.2°, respectively. These bond lengths and angles closely resemble those in the porphyrin core of octaethylporphyrin. We conclude that the asymmetric pattern of substitution of mesoporphyrin IX dimethyl ester affects the bond lengths and bond angles within the porphyrin core to less than can be detected by this structure determination.
ASJC Scopus subject areas
- Colloid and Surface Chemistry