Molecular and electronic structure of Si(IV), Ge(IV), Sn(IV), Pb(IV) porphyrazines: DFT-study

The molecular and electronic structures of porphyrazine complexes XPzY₂ (X = Si(IV),Ge(IV),Sn(IV),Pb(IV), Y=F,Cl,Br,OH) have been studied by DFT calculations. Geometries of complexes with Si and Ge were found to possess D_4h symmetry with a planar structure of macrocyclic core and axial ligands located on different sides of it. The complexes with Pb are dome-shaped distorted due to its higher ionic radius compared to other central atoms considered, while in the case of tin conformational preferences depend on the axial ligand nature. The lowest excited electronic states have been calculated using the TDDFT calculations. The position of the Q-band is slightly affected by the nature of the central atom, but the influence of the axial ligand and the distortion of the macrocyclic core is more significant. In addition, a comparison of the geometric structure of porphyrazines with the corresponding porphyrins was carried out, thus the total number of objects studied was 32 molecules.