Catalytic properties of supramolecular polymetallated porphyrins

Supramolecular polymetallated pyridylporphyrins have been specially designed for exploring the binding and synergism between the macrocyclic system and the peripheral metal complexes. Their chemistry has been reviewed, focusing on the outstanding behavior in solution or as thin organized films generated with several nanomaterials, for application as molecular devices and in energy conversion processes.

Crown Ether—Pillararenes Hybrid Macrocyclic System

Combination of Nobel macrocycle—crown ether and star macrocycle—pillararenes together in organic synthesis and material science is significant to grant thus obtained hybrid systems, rigid/flexible structural architecture, induced planar chirality, negative...

Synthesis Novel Fluorinated Cyclic Nanomeric Aza Crown Macrocyclic System Containing 1,2,4-triazine moiety and Ru-complex as Cyclin-dependent kinase 2 (CDK2) inhibitors of tumor cells (Protection of DNA Damage)-Part II

Novel fluorinated 1,5-disubstituted-1,3,5-triazepine-6,7-dione (4) has been obtained from the interaction between 5,6-bis(4-fluorophenyl)-1,2,4-triazine-3-thiol (1) with 2,6-diaminopyridine 2 followed by ring closer reaction with diethyl oxalate. Also, Ru-complex 7 obtained by refluxing of compound 1 with 6-(4-fluorophenyl)-1,2,4-triazine-3,5-diamine (5) to produce compound 6, the later was reacted with RuCl3.xH2O to produce the target 7. Structures of the products deduced from their elemental analysis and spectral measurements. Compounds 3, 4, 6, and 7 were evaluated as CDK2 inhibitors of tumor cells; these compounds exhibited a potential activity against CDK2, where the IC50 values were 4.5, 6.8, 4.0, and 5.0 μM respectively in comparison with Olomoucine standard (IC50=5.0 μM).

Study on the Effects of a π Electron Conjugated Structure in Binuclear Metallophthalocyanines Graphene-Based Oxygen Reduction Reaction Catalysts

The high overpotentials for oxygen reduction reaction (ORR) create an extremely negative impact on the energy efficiency of the air-based battery systems. To overcome this problem, binuclear ball-type metallophthalocyanines containing methoxy substituents (M2Pc2(EP)4, M = Fe(II), Co(II) and Zn(II)) were wrapped with polystyrene sodium sulfonate (PSS) modified graphene oxide (GO), using a facilely “solvothermal π-π assembly” method to prepare M2Pc2(EP)4/PSS-Gr composites. Compared with the commercial Pt/C catalysts, the M2Pc2(EP)4/PSS-Gr composites enhanced the catalytic activity of oxygen reduction reaction. The π electron conjugated structure of the MN4-type phthalocyanine macrocyclic system strongly influenced the one-step four-electron electrocatalytic process of the M2Pc2(EP)4/PSS-Gr composites. Moreover, the π-π interactions between the M2Pc2(EP)4 and PSS-Gr dramatically enhanced the π electron density in the conjugated structure and oxygen could be reduced more easily. The electrocatalytic activity test was displayed in the order of Fe2Pc2(FP)4/PSS-Gr > Co2Pc2(EP)4/PSS-Gr > Zn2Pc2(EP)4/PSS-Gr. The results indicated that the catalytic performance of M2Pc2Rn could be enhanced by the modification of π electron conjugated structure of M2Pc2(EP)4 and carbon materials.

A macrocyclic oligofuran: synthesis, solid state structure and electronic properties

The first π-conjugated macrocyclic system with an oligofuran backbone display planar conformation and forms large π-aggregates, in contrast to the twisted conformation of small macrocyclic oligothiophenes.

Theoretical AM1 study of acidity of porphyrins, azaporphyrins and porphyrazines

The structure-acidity relationship in the series of non-substituted, meso- or β-substituted and β,β-annulated porphyrins and porpyrazines have been studied using the AM1 method with unrestricted Hartree-Fock basis set. With this purpose, heats of formation have been determined for the geometry optimized structures of the free base macrocycles and corresponding monoanions and dianions formed by deprotonation. Calculated first deprotonation enthalpy values show correlation with available experimental p K1avalues and can be used for prediction of acidity. For porphyrazines bearing electron-withdrawing substituents or π-deficient annulated heteroarens the dianions have lower heats of formation than the corresponding neutral species and such porphyrazines are easily deprotonated upon dissolution in basic solvents (pyridine, DMF). For porphyrazines with annulated 5-member heteroarens it is predicted that deprotonation of peripheral NH groups should occur more easily than deprotonation of the internal NH groups. The influence of different types of annulation of 5- and 6-membered heteroarens to the porphyrazine core on the stability of the macrocyclic system and its acidity are also discussed.