Complexes of Transition Metals with Petroleum Porphyrin Ligands: Preparation and Evaluation of Catalytic Ability

Abstract

In the present work, the first data on the catalytic activity of d-metal complexes of petroleum porphyrins obtained via two-stage re-metallization (acid demetallization with subsequent metalation) of high-purity petroleum vanadyl porphyrins are presented. During acid demetallization of petroleum vanadyl porphyrins, the highest yield (49%) and spectral purity of free petroporphyrin bases were achieved with concentrated sulfuric acid and a diluted solution of vanadyl porphyrins in chloroform. In the series of divalent cations of Mn, Fe, Co, Ni, Cu, and Zn, only the last four metals are complexed with demetallated petroporphyrins without significant changes in their component composition, whereas the interaction with Mn and Fe cations causes an evident structural transformation or even full degradation of petroporphyrin macrocycles, respectively. The composition and spectral purity of petroleum porphyrin-containing reactants and products were analyzed by FT-IR, UV-Vis, NMR, and MALDI-TOF mass spectroscopic methods. The obtained petroporphyrin-based d-metal complexes were assayed by the reaction of 2-mercaptoethanol oxidative dimerization, in which the copper porphyrins exhibited the highest catalytic activity.

V-Porphyrins Encapsulated or Supported on Siliceous Materials: Synthesis, Characterization, and Photoelectrochemical Properties

“…The DR-UV–vis spectra of catalysts are shown in Figure 3 , whereas those related to the pure VTPP sample are presented in Figure S7 . DR-UV-vis spectra of catalysts show three bands: an intense band at 410 nm (Soret band) and a doublet at 533 nm (β band) and 572 nm (α band) that is related to Q bands, which is in good agreement with previous results for pure [ 24 , 25 , 26 , 27 , 28 , 29 , 43 ] or supported/encapsulated [ 30 ] vanadyl porphyrins.…”

“…The presence of C–H groups was indicated by the bands at 2869 (CH 3 asymmetric stretching), 2930 (symmetrical CH 2 ), and 2967 cm −1 (asymmetrical CH 2 ), in addition to those at 1443, 1373, and 705 cm −1 [ 14 , 25 , 50 , 51 ], whereas the presence of C-C groups was indicated by the band at 1465 cm −1 [ 51 ]. On the other hand, the presence of a pyrrole C-N bond was indicated by the band at 775 cm −1 [ 51 ], and the bands at 1058 and 844 are related to N-H vibration [ 50 ].…”

“…Therefore, the search for new applications of these V-containing petroporphyrins is highly interesting. Vanadium(IV)-porphyrin-containing materials are also paramount [ 24 , 25 , 26 , 27 ], in which special attention has been paid to the use of Vanadyl-porphyrins incorporated on the surface of supports or encapsulated in mesoporous materials [ 13 , 28 , 29 , 30 , 31 , 32 ]. It is well-known that changes in the type of functional groups and/or in the position of the substituents in the porphyrin macrocycle can give rise to modifications in the physicochemical and catalytic properties [ 6 , 7 , 8 , 9 ], but significant changes in physicochemical characteristics could also occur when incorporating metalloporphyrins into inorganic oxides [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 28 , 29 , 30 , 31 , 32 ].…”

“…Vanadyl-porphyrins present interesting electrical properties [ 13 , 24 , 25 , 26 , 27 ] and could be of interest to be used as catalysts in electrochemical reactions. However, to the best of our understanding, no research article has been published that focused on the photoelectrochemical characteristics of bulk and supported vanadyl-porphyrins.…”

An Indium Synthetic Etioporphyrin for Organic Electronics: Aggregation and Photoconductivity in Thin Films

“…Complexes of etioporphyrin with transition metals (Ni, Cu) and metal oxides (VO, TiO) can be found in nature as trace components of heavy oils and asphaltenes [1–3] . Their laboratory synthesis is well‐known to yield compounds with a strictly defined substitution pattern [4–6] . Because of their good stability against heating on the one hand, and poor solubility on the other hand, the most suitable method for obtaining thin solid films of etioporphyrins is thermal vacuum evaporation.…”