Role of methyl substitution on the spectroscopic properties of porphyrazines. A TDDFT study using pure and hybrid functionals on porphyrazine and its octamethyl derivative

Time-dependent density functional theory (TDDFT) has been used to analyse the UV–Vis spectrum of the nickel octa ethyl substituted porphyrazinato complex. The correct ordering of the main bands (Q, B, N and several shoulders) of the experimental spectrum has been studied comparing results among different pure (BP, BLYP, LB94 and SAOP) and hybrid (B3LYP) functionals. Strong effects in the computed spectra have been shown to be related to the alkyl substitution on the previously studied unmethylated compounds.