Theoretical study of nickel porphyrinate derivatives related to catalyst dopant in the oil industry

Ni-porphyrinate is totally planar hence exhibiting a marked difference with respect to the analogous vanadyl compound which has been shown to have a dome shape. The Ni-porphyrinates studied in the present work exhibit a slight non-planar shape. The origin of this strain has been attributed to the reduced space of the porphyrin molecule cavity and also to the presence of peripheral substituents. It appears that the largest deviation from planarity occurs in the case of phenyl substituents whereas in both aliphatic cases a similar strain is predicted. This feature could be attributed to a large increase in the electronic density near the metal center caused by the presence of the aromatic rings.