Facial discrimination in monoarylporphyrins: Synthesis and stereochemical behaviour of bis(ligated) monospirobifluorenylporphyrin ruthenium complexes

Condensation of dipyrromethane, pyrrole-2-carbaldehyde with either 9,9′-spirobifluorene or fluorene aldehyde yields new meso-monosubstituted, β-unsubstituted porphyrins. The large size of spirobifluorene hinders the rotation around the Cmeso-Caryl bond to give, for bis-ligated complexes, two different topological faces.