Deuterated cis- and trans-Di[benzo]porphyrazines: Theoretical Consideration of (D,D)-Isomerism using the DFT Model Chemistries

Abstract

Using two versions of the density functional theory (DFT), namely B3PW91/TZVP and DFT M06/def2TZVP, a quantum-chemical calculation of the molecular structures of potential isomeric [benzo]annulated derivatives of porphyrazine—cis- and trans-di[benzo]porphyrazines containing deuterated groups (ND) in positions 21 and 23 was performed. It was found that the first of these compounds can exist in the form of four, while the second—in the form of two isomers, differing from each other in the mutual orientation of the deuterium atoms bonded to the nitrogen atoms. The main parameters of the molecular structures of these (D,D)-isomeric compounds, as well as the values of their total energies, standard enthalpy, entropy and Gibbs energy of formation are presented. It has been established that the most stable among deuterated di[benzo]porphyrazines is the (D,D)-isomer with trans-orientation of deuterium atoms bound to nitrogen atoms, whereas (D,D)-isomers with cis-orientation of deuterium atoms have significantly higher total energies. It has also been noted that for each of di[benzo]porphyrazines, (D,D)-isomer is more stable than corresponding (H,H)-isomer.