XANES quantitative structural determination of the sandwich bis(naphthalocyaninato) cerium complex

The molecular structure of the sandwich double-decker bis(naphthalocyaninato) cerium complex was determined for the first time in a quantitative way using a new method of analysis of the Ce L3-edge X-ray absorption near-edge structure (XANES) in the framework of the full multiple scattering theory. An average Ce-N bond length of 2.47 A was determined. In this complex structure the pyrrole rings play the key role in the determination of the XANES spectral features, and the differences in bond lengths between the Ce atom and the eight pyrrole N atoms are 0.14 A, addressing a significant distortion of these rings around cerium. These results may be used to study double-decker imidazole rings, present as the structure model in the photosynthesis center and in sandwich-structured lanthanide chlorophyll molecules.