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

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.

Solvent-free Synthesis, Characterization and Biological Activity of Transition Metal Complexes of Schiff Base Ligand Derived from 2-Amino Benzimidazole with 4, 4’Dibromobenzil

Microwave-assisted synthesis and characterization of Schiff base ligand complexes of transition metals such as Mn(II), Fe(III), Co(II), Ni(II),Cu(II), Zn(II) Cd(II), and Ag(I) (using Schiff base) prepared by irradiation of 2-Amino benzimidazole with 4,4’dibromo benzil. The Synthesized transition metal complexes and Schiff base ligand have been representatively characterized by elemental analysis and spectral methods such as UV, IR, 1H-NMR, LC-MS, and Thermal analysis. The synthesized ligand and its complexes were also screened for their biological activities, such as antibacterial activity against bacterial species Staphylococcus aureus, Escherichia coli, and Salmonella Typhi. The result indicated that the complexes exhibited octahedral geometry.

METAL COMPLEX CATALYSIS

Complexes of transition metals with chiral ligands are considered as catalysts. Among metal-containing organic complexes with semiconducting properties, compounds of the porphin series occupy a special place in electrocatalytic studies. The properties of the porphyrin macrocycle, their role in catalysis, and the influence of the nature of the metal on the catalytic properties of the complex are considered.

Bis(dicarbollide) Complexes of Transition Metals as a Platform for Molecular Switches. Study of Complexation of 8,8′-Bis(methylsulfanyl) Derivatives of Cobalt and Iron Bis(dicarbollides)

Complexation of the 8,8′-bis(methylsulfanyl) derivatives of cobalt and iron bis(dicarbollides) [8,8′-(MeS)2-3,3′-M(1,2-C2B9H10)2]− (M = Co, Fe) with copper, silver, palladium and rhodium leads to the formation of the corresponding chelate complexes, which is accompanied by a transition from the transoid to the cisoid conformation of the bis(dicarbollide) complex. This transition is reversible and can be used in design of coordination-driven molecular switches based on transition metal bis(dicarbollide) complexes. The solid-state structures of {(Ph3P)ClPd[8,8′- (MeS)2-3,3′-Co(1,2-C2B9H10)2-κ2-S,S′]} and {(COD)Rh[8,8′-(MeS)2-3,3′-Co(1,2-C2B9H10)2-κ2-S,S′]} were determined by single crystal X-ray diffraction.

Thiosemicarbazone Complexes of Transition Metals as Catalysts for Cross-Coupling Reactions

Catalysis of cross-coupling reactions under phosphane-free conditions represents an important ongoing challenge. Although transition metal complexes based on the thiosemicarbazone unit have been known for a very long time, their use in homogeneous catalysis has been studied only relatively recently. In particular, reports of cross-coupling catalytic reactions with such complexes have appeared only in the last 15 years. This review provides a survey of the research in this area and a discussion of the prospects for future developments.