14187-13-4Relevant articles and documents
Acid-base and coordination properties of some palladium(II)porphyrins
Tyulyaeva,Kosareva,Klyueva,Lomova
, p. 1405 - 1410 (2008)
The speciation and reactions of palladium(II) complexes with meso-tetraphenylporphine (H2TPP) and meso-tetraphenyl-β- octaethylporphine (H2TetPOEP) were studied in H2SO 4-H2O and H2SO4-HOAc protic solvents. H-associated species of PdTPP and PdTetPOEP were found to exist in sulfuric acid with concentrations of 16.33-17.38 and 17.48-18.22 mol/L, respectively. The kinetics of one-electron oxidation of complexes in the coordinated aromatic macrocycle were studied. A third-order rate equation was determined, and the mechanism of the oxidation reaction was substantiated with kinetically significant stages of dioxygen coordination, electron transfer from the macrocyclic aromatic system to dioxygen, and H-association equilibrium between the complex and sulfuric acid. The effects of peripheral ethyl substituents in the macrocyclic ligand on the reactivity of palladium(II) porphyrins were revealed.
Pd-porphyrin complex-catalyzed allylation of indole with allylic alcohols through C3–C2 coupling
Atia, Alaa A.,Kimura, Masanari
, (2021)
Appropriate and efficient way for the preparation of 3-allyl-2,3-dihydro-2,3′-bisindoles has been developed via homocoupling of N–H indole. Pd-porphyrin-catalyzed allylation of indoles with allylic alcohols in the presence of PBr3 and a base is developed. The reaction involves dimerization at the C3 and C2 positions of the indoles, giving 2-allylated 3-(indolin-2-yl)-1H-indoles in moderate to good yields. 3-(Indolin-2-yl)-1H-indole derivatives serve as intermediates for the synthesis of pharmaceutically active molecules.
Study of tetraphenylporphyrins as modifiers of insulin amyloid aggregation
Chernii, Svitlana,Losytskyy, Mykhaylo,Kelm, Anna,Gorski, Alexandr,Tretyakova, Iryna,Yarmoluk, Sergiy,Chernii, Victor,Kovalska, Vladyslava
, (2020)
Amyloid fibrils are rigid β-pleated protein aggregates that are connected with series of harmful diseases and at the same time are promising as base for novel nanomaterials. Thus, design of compounds able to inhibit or redirect those aggregates formation is important both for the biomedical aims and for nanotechnology applications. Here, we studied the effect of tetraphenylporphyrins (metal free, their Cu and Pd complexes, and those functionalized by carboxy and amino groups on periphery) on insulin amyloid self-assembling. The strongest impact on insulin aggregation was demonstrated by a metal-free porphyrin bearing four carboxy groups. This compound strongly suppresses insulin aggregation (about 88% reduction in amyloid-sensitive probe emission) inducing formation of fibrils with the length close to this of free insulin (1.7 ± 0.6 μm as compared with 1.4 ± 0.4 μm, respectively) with an essentially reduced tendency to lateral aggregation. Contrarily, the presence of tetraphenylporphyrin containing four amino groups only slightly affects fibrils' morphology and makes weaker impact on insulin aggregation yield (about 44% reduction). This is explained by the ability of aromatic carboxy groups of 5,10,15,20-(tetra-4-carboxyphenyl)porphyrin to interact with complementary protein-binding groups and thus stabilize the supramolecular complex. For 5,10,15,20-(tetra-4-aminophenyl)porphyrin, full protonation takes place in acidic medium of protein aggregation reaction; this results in the high positive charge of TPPN4 (equal or close to +6) and hence higher contribution of coulombic repulsion to interaction of TPPN4 with insulin. One more possible mechanism of the lower inhibition effect of TPPN4 as compared with TPPC4 could be the more restricted possibility of the former as compared with the latter to form H bonds with insulin groups. It was also shown that metal-free, Pd-containing, and Cu-containing tetraphenylporphyrins without peripheral substituents make almost the same impact on the protein self-assembling. We suppose this to be due to coordination saturation of these metal atoms.
Combining metalloporphyrins and cyclometalated complexes – A luminous pair?
Borisov, Sergey M.,Moritz, Yvonne,Steinegger, Andreas
, (2020/12/04)
Cyclometalation is investigated as a method to modulate the photophysical properties of phosphorescent (benzo)porphyrins. For cyclometalation with Pt(II), 2-pyridyl groups were incorporated into three Pd(II) porphyrin complexes. Integration of the freely rotating cyclometalated 2-phenylpyridyl based motif in meso-position does not lead to notable spectral changes and only affects the luminescence decay time (about 2-fold decrease) in solution at room temperature. The decay times, however, are not affected in frozen glass at 77 K or immobilized into a rigid polystyrene matrix. In contrast, cyclometalation involving a 2-pyridyl unit in meso-position and the β-H of the porphyrin results in a large bathochromic shift (～ 1900 cm?1) of Q-bands in the absorption spectrum and the phosphorescence peak. A drastic decrease of the phosphorescence lifetime (about 20-fold) also is observed. Cyclometalation is accompanied by an increase of the singlet oxygen quantum yield to 85 % making the new dye a powerful red-light excitable 1O2 photosensitizer.
