Tetrapyrrole Macroheterocyclic Compounds. Structure–Property Relationships

Molecular And Solid‐State Structure Of Oxovanadium(IV) Etioporphyrin‐III

“…[21] VO-EtioP-I adopts a triclinic system, its crystal packing resembles the "slipped stacks" typical of many symmetrical porphyrins. [1,17,28] Thus, the intra-and intermolecular structure of VO-EtioP-III differs from that of similar polar and nonpolar (but having a similar ligand) porphyrin complexes. The upward orientation of ethyl groups in Figure 1(a) is very likely a combined effect of the out-of-plane displacement of vanadium atom and the relative position of all peripheral alkyls.…”

“…Complexes of vanadium with porphyrin ligands are the most abundant metalorganic chelates found in the fossil fuels of various kinds. [1][2][3][4][5][6][7][8][9] Among the porphyrin ligands, the etio-type (i. e. alkyl-porphyrin) is the simplest: a classical EtioP ligand bears four methyl and four ethyl groups attached to the outer C β atoms in each pyrrole unit. Hence, four position isomers are possible for etioporphyrin ligand, being commonly labeled by Roman numbers.…”

“…Hence, four position isomers are possible for etioporphyrin ligand, being commonly labeled by Roman numbers. [1,5,6,[10][11][12][13][14] All of them can be synthesized in laboratory using non-natural precursors. [1,[10][11][12]15,16] It is generally believed that only one, the least symmetrical isomer EtioP-III exists in nature, a fact closely related to the biogenic theory of petroleum formation (Treibs scheme).…”

“…[1,5,6,[10][11][12][13][14] All of them can be synthesized in laboratory using non-natural precursors. [1,[10][11][12]15,16] It is generally believed that only one, the least symmetrical isomer EtioP-III exists in nature, a fact closely related to the biogenic theory of petroleum formation (Treibs scheme). [4][5][6]9,17] However, this fact itself is not indisputable, [6,12,13,16] and the controversy around this theory has not subsided over the past half century, which makes identification of particular isomer an important task.…”

“…Single-crystal X-ray diffraction (XRD) can provide an unambiguous picture of threedimensional atomic structure of a molecule, but this method is rarely applied to the petroporphyrins and the crystallographic data available today are usually several decades old. [1,12,21,22] A likely reason is the difficulties involving in growing single crystals appropriate for analysis. [14] Molecular structure of such a classical petroporphyrin as oxovanadium(IV) etioporphyrin-III (VO-EtioP-III), which is also commercially available under CAS no.…”