Experimental and Theoretical Study of Electronic Structure of Zinc Phthalocyanines ZnPc and ZnPcF₁₆

The electronic structure of zinc phthalocyanines ZnPc and ZnPcF₁₆ is studied by X-ray emission and X-ray photoelectron spectroscopy methods. Experimental and theoretical parameters of the energy spectrum are analyzed along with the partial composition of highest occupied molecular orbitals (HOMOs) of the molecules of these compounds. It is shown that the frontier high-energy region of ZnPc HOMOs consists of 2p_π atomic orbitals (AOs) of nitrogens from non-equivalent groups (N_α, N_β) and 2p_π orbitals of peripheral carbons (C_βγδ) with the participation of 3d orbitals of zinc which belong to both π (3d_yz, 3d_z2) and σ (3d_xy) types. It is established that fluorine atoms and the central zinc atom in ZnPcF₁₆ interact with each other by forming delocalized π orbitals with the participation of carbon p_π orbitals belonging to α, β, γ, δ groups as well as nitrogen p_π orbitals of α and β groups. The HOMO of ZnPcF₁₆ consists mainly of 2p_x and 2p_y AOs of nitrogen (N_α and N_β) and carbon (C_β and C_γδ) with a small contribution of the 3d_{xz, yz} orbital of zinc.