Solvent effects are described using the Polarizable Continuum Model (the integral equation formalism variant, IEFPCM, as implemented in Gaussian 16). The absorption spectra of the compounds were predicted by means of the TD-DFT formalism using almost all possible hybrid and standalone pure density functionals (Table ), available in Gaussian 16. For reasons that will be described in the next section the discussion is concentrated on B3LYP, B3P86 42,43 , mPW1LYP , APFD , X3LYP 46 and PBE0 . For consistency with the discussed work, TPSS is also used. In all cases the TD-DFT calculations are based on M06-2X/def2TZVP+D3 geometry. The absorption spectra were simulated as described in by using half-band width of 3500 cm -1 .