Macrocyclic scaffolds are particularly attractive for designing selective G-quadruplex ligands essentially because, on one hand, they show a poor affinity for the "standard" B-DNA conformation and, on the other hand, they fit nicely with the external G-quartets of quadruplexes. Stimulated by the pioneering studies on the cationic porphyrin TMPyP4 and the natural product telomestatin, follow-up ...

The nuclease hypersensitivity element III(1) upstream of the P1 promoter of c-MYC controls 85-90% of the transcriptional activation of this gene. We have demonstrated that the purine-rich strand of the DNA in this region can form two different intramolecular G-quadruplex structures, only one of which seems to be biologically relevant. This biologically relevant structure is the kinetically favo...

Heterogeneous catalysis and their application in industrial-scale organic synthesis of fine chemicals are greatly facilitated by catalysis and further on by catalyst recovery and recycles to fits most “principles of green chemistry. In acid media, terpenoids generally undergoes various transformations. The terpenoid transformations include various liquid Bronsted and Lewis Acids, Acid clays, He...

The excited-state quenching of zinc meso-tetrakis(4-sulfonatophenyl)porphyrin (ZnTPPS) by halide ions has been studied in water and various aqueous micellar solutions using both steady-state and time-resolved fluorescence techniques. The quenching efficiencies of the S(1) state of ZnTPPS ([small tau][approximate] 1.93 ns) by halide ions in homogeneous aqueous solution increase in the order Cl(-...

PURPOSE To determine the effects of human retinal pigment epithelial (RPE) cell pigment granules on photosensitized and iron ion-mediated oxidation and the effect of the photodegradation of melanosomes on their antioxidant properties. METHODS RPE cells were isolated from human and bovine eyes; pigmented and nonpigmented bovine retinal pigment epithelia were isolated separately. Melanosomes, m...

Increased interest in clinical application of photodynamic therapy (PDT) in various medical fields poses a demand for better understanding of processes triggered by photo-treatment. Most of the work on PDT performed so far has focused on the immediate effects of photo-treatment. It is generally accepted that cellular damage occurs during light exposure and within a short period thereafter. If c...

The asymmetric unit of the title complex, [Co(C(5)H(5)N(3)O)(2)(H(2)O)(2)](NO(3))(2), contains one half of a Co(II) cationic unit and a nitrate anion. The entire [Co(C(5)H(5)N(3)O)(2)(H(2)O)(2)](2+) cationic unit is completed by the application of inversion symmetry at the Co(II) site, generating a six-coordinate distorted octa-hedral environment for the metal ion. The chelating pyrazine-2-carb...

The asymmetric unit of the polymeric title compound, {(C21H19N2)[HgCl3]} n , comprises one-half of the cationic mol-ecule, the other half being generated by application of twofold rotation symmetry, one Hg and two Cl atoms. The Hg(II) atom, lying on a twofold rotation axis, exhibits a distorted triangular coordination environment and is surrounded by three Cl atoms with Hg-Cl distances in the r...

The asymmetric unit of the title compound, [RhCl(2)(C(10)H(8)N(2))(2)]ClO(4), consists of one unit of the cationic complex [RhCl(2)(bipy)(2)](+) and one uncoordinated perchlorate anion. The Rh(III) atom is coordinated by four N atoms from two bipyridyl ligands and two Cl atoms, forming a distorted octa-hedral environment. The Cl ligands are cis. Two intramolecular C-H⋯Cl hydrogen bonds occur in...

Abstract. Porphyrin rings containing two meso-pyridyl groups either in cis or trans fashion can be used to construct Re(I) bridged multiporphyrin assemblies. The cis-dipyridyl porphyrins with various porphyrin cores such as N4, N3O, N3S, N2S2 have been used to react with Re(CO)5Cl in THF at refluxing temperature and constructed planar Re(I) bridged porphyrin dyads containing either one type of ...