24804-00-0Relevant academic research and scientific papers
Transformations of meso-Iminofunctionalized Pd(II) and Ni(II)-Complexes of β-Alkylsubstituted Porphyrins
Erzina, Dina R.,Zamilatskov, Ilya A.,Stanetskaya, Nadezhda M.,Tyurin, Vladimir S.,Kozhemyakin, Grigory L.,Ponomarev, Gelii V.,Chernyshev, Vladimir V.,Fitch, Andrew N.
, p. 1508 - 1522 (2019/02/13)
The meso-imino derivatives of the palladium (II) and nickel (II) complexes of coproporphyrins I and II and β-octaethylporphyrin were obtained by the Vilsmeier formylation followed by interaction with amines. The metal complexes of the azomethines obtained were transformed to the corresponding complexes of cyclopentane and cyclopentane-pyrrolidone fused porphyrin derivatives by thermolysis. The plausible mechanism of such transformations was suggested and substantiated with quantum chemical calculations. Meso-cyano-, meso-hydroxy-, and meso-aminocarbonyl derivatives of β-octaethylporphyrin were obtained by treatment of the corresponding meso-imino derivatives with bases. Demetalation of the nickel complex of the meso- hydroxy-β-octaethylporphyrin led to formation of the free base derivative. The structures of new types of the porphyrin derivatives were determined via X-ray powder diffraction analysis. The obtained types of porphyrins are promising candidates to use as photosensitizers in medicine applications due to their longer wave absorption combined with high stability.
Structural modification and kinetic stability of octaethylporphyne complexes with palladium (II)
Lomova,Klyueva,Tyulyaeva, E. Yu.
, p. 926 - 933 (2011/08/04)
The influence of gradual meso-phenyl substitution in 2,3,7,8,12,13,17,18- octaethyl-21H,23H-porphyne (H2OEP) on the stability of its complexes with Pd(II) in comparison to the meso-tetraphenylporphyne complex with unsubstituted Cβ atoms is investigated by means of the chemical kinetics and physicochemical analysis. Using the spectral methods, the states and reactions of complexes in the AcOH-H2SO4 mixures is studied for the wide range of compositions. It is found that, the coordination centers are stable in mixtures with compositions of up to 100% of H 2SO4. Whether in the molecular state or in association with a proton (PdOEP and its mono-meso-phenyl derivative), the complexes undergo transformations that are investigated by chemical kinetics. It is shown that instead of the usual dissociation of the coordination center, single-electron oxidation in the macrocycle of complexes takes place. A multistage mechanism is revealed that involves the kinetically significant equilibrium between the formation of H-associated complex and irreversible coordination of molecular oxygen, followed by the acid-assisted transfer of an electron from the aromatic system to this oxygen. The oxidation stability of complexes is determined, and the relation between the structure of macrocyclic ligand and the electronic structure of coordination center is discussed.
The kinetics of disproportionation of hydrogen peroxide in the presence of palladium(II)porphyrins with regularly changing macroring structures
Lomova,Klyueva,Kosareva,Klyuev
, p. 1086 - 1092 (2008/12/21)
The kinetics and spectral manifestations of alkaline decomposition of H2O2 in a water-dimethylformamide medium catalyzed by PdIIP (P is the dianion of octaethylporphyrin and its monophenyl, 5,15-diphenyl,5,10-diphenyl, triphenyl, and tetraphenyl derivatives substituted at meso positions) was studied over a wide range of reagent concentrations under polythermal conditions. A complete kinetic description of the reacting systems was given, and the rates and set of elementary reactions, intermediate compounds, and kinetically significant equilibria were determined. The ion-molecular mechanism of hydrogen peroxide decomposition was substantiated. According to this mechanism, the only stable radicals involved in the reaction are the π radical cation forms of palladium(II)porphyhrin catalysts.
Effect of the chemical modification of the tetrapyrrole macrocycle on the reactivity of porphyrins in complexation with Pt4+ and Pd 2+ cations
Chizhova,Mamardashvili
, p. 250 - 253 (2008/10/09)
The reactions of 5,10,15,20-tetraphenylporpine, 5,10,15-triphenyl-20-(4- hexadecanoxyphenyl)porphine, 5,10,15,20-tetra-(4-butoxyphenyl)porphine, and 2,3,7,8,12,13,17,18-ocaethylporphine with H2PtCl6 in boiling phenol and with PdCl2 in boiling dimethylformamide are studied by spectrophotometry. Due to a strong electronic effect of the substituents, the reactivity of the tetrapyrrole macrocycle during porphyrinate formation changes by more than two orders of magnitude. Platinum(II) 5,10,15-triphenyl-20-(4-hexadecanoxyphenyl)porphinate and palladium(II) 5,10,15,20-tetra-(4-butoxyphenyl)porphinate have been synthesized and identified for the first time. Nauka/Interperiodica 2007.
Synthesis, characterization, and electrochemistry of copper(II) and palladium(II) hydroporphyrins: The copper(I) octaethylisobacteriochlorin anion
Stolzenberg, Alan M.,Schussel, Leonard J.
, p. 3205 - 3213 (2008/10/08)
The Cu(II) and Pd(II) complexes of trans-octaethylchlorin (OEC) and octaethylisobacteriochlorin (OEiBC) were synthesized and characterized. The redox behavior of these complexes and of the octaethylporphyrin complexes Cu(OEP) and Pd(OEP) were investigated in nonaqueous media. Potentials were determined by cyclic voltammetry in butyronitrile, methylene chloride, and dimethylformamide solutions. Oxidized and reduced species derived from these complexes were characterized by spectroscopic means. The first oxidation of all six complexes afforded M(II) cation radicals. The palladium(II) hydroporphyrin cation radicals were unstable on the time scale of electrolysis in all three solvents. With the exception of Cu(OEiBC), electrochemical reduction of the complexes afforded M(II) anion radicals. Chemical reduction of these complexes did not give the anion radicals, but instead proceeded directly on to the phlorin anion or chlorin-phlorin anion complexes, M(OEPH)- and M(OECH)-, respectively. Electrochemical or chemical reduction of Cu(OEiBC) afforded the stable diamagnetic CuI(OEiBC)- anion. Unlike other CuIN4 complexes, CuI(OEiBC)- does not appear to have measurable affinity for additional ligands. The rate of oxidation of the highly reducing CuI(OEiBC)- anion by O2 or by alkyl halides is slower than for NiI(OEiBC)-, an anion with a nearly equal reduction potential.
