Pair correlation function analysis of 5-(4-hexadecyloxyphenyl)-10,15,20-tri(4-pyridyl)porphyrin and 5-(4-methoxycarbonylphenyl)-10,15,20-tri(4-pyridyl)porphyrin

The high-energy X-ray diffraction measurements were carried out for 5-(4-hexadecyloxyphenyl)-10,15,20-tri(4-pyridyl)porphyrin and 5-(4-methoxycarbonylphenyl)-10,15,20-tri(4-pyridyl)porphyrin. The scattered intensities were recorded on the ID15B beam line at the European Synchrotron Radiation Facility (ESRF), Grenoble, France. An incident beam-energy of 90.45 keV was used, corresponding to a wavelength of 0.1374 Å. The pair correlation functions were obtained from the measured intensities via the Fourier transform. The density-functional theory was used to construct structural models of both molecules consisting of the atomic Cartesian coordinates. For these models the pair correlation functions were computed. The constructed models reproduce satisfactorily features of the experimental pair correlation functions. The results of such simulations are discussed in the framework of the density-functional approach.