Flavonoids are common plant natural products able to suppress ROS-related damage and alleviate oxidative stress. One of key mechanisms, involved in this phenomenon is chelation of transition metal ions. From a physiological perspective, iron is the most significant transition metal, because of its abundance in living organisms and ubiquitous involvement in redox processes. The chemical, pharmaceutical, and biological properties of flavonoids can be significantly affected by their interaction with transition metal ions, mainly iron. In this review, we explain the interaction of various flavonoid structures with Fe(II) and Fe(III) ions and critically discuss the influence of chelated ions on the flavonoid biochemical properties. In addition, specific biological effects of their iron metallocomplexes, such as the inhibition of iron-containing enzymes, have been included in this review.

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The design and synthesis of glycol-functionalized porphyrins that contain one to four low molecular weight glycol chains that are linked via ether bonds to the meta-phenyl positions of meso-tetraphenylporphyrin and the comparison of fluorinated and nonfluorinated para derivatives are reported. The cellular uptake and photodynamic activity significantly depend on terminal groups of the glycol substituent. Hydroxy glycol porphyrins, in contrast with methoxy glycol porphyrins, show efficient intracellular transport and a high induction of apoptosis in tumor cell lines in vitro . Furthermore, the ethylene glycol chain at the meta position exhibits a superior efficacy that leads to the permanent ablation of human breast carcinoma (MDA-MB-231) in nude mice. In addition, fluorination enhanced the photosensitizing potential of para-phenyl derivatives. The analysis of the cell-death mechanism revealed that glycol-functionalized porphyrins represent novel nonmitochondrially localized photosensitizers that have a profound ability to induce apoptosis in tumor cells that act upstream of caspase activation. The strong interaction with a tumor marker (sialic acid) indicates the preferential association of these compounds with tumor cells.

Different bridging geometries can explain the observation that porphyrin molecules with added thiol end groups and pyridine axial groups form more‐stable single‐molecule junctions with an increased spread in low‐bias conductance. The stability of these geometries is demonstrated by time‐dependent conductance measurements. In contrast, rodlike molecules show one preferential binding geometry.

Metallacarborane moieties have been identified as promising pharmacophores. The pharmaceutical use of such compounds is, however, complicated by their low solubility and tendency to self-assemble in aqueous solution. In this work, we estimated the solubilities of a vast series of metallacarboranes [cobalt bis(dicarbollide) derivatives] in pure water, saline, and saline with human serum albumin as a model of blood plasma. In addition, we determined the octanol-water partition coefficients (Pow) as a lipophilicity descriptor. Pow weakly correlates with the water solubility of metallacarboranes, whereas the ability of HSA to increase the solubility of metallacarboranes correlates well with their Pow values. Because metallacarboranes are known inhibitors of HIV protease, the possible correlation between Pow and the ability to inhibit HIV protease was investigated. Results from this study indicate that interaction of metallacarborane inhibitors with HIV protease is driven by specific binding rather than by promiscuous lipophilic interactions. The most promising candidates for further drug development were identified by ligand lipophilicity efficiency analysis.

Unterschiedliche Brückengeometrien können die Beobachtung erklären, dass Porphyrinmoleküle mit Thiolendgruppen und axialen Pyridingruppen stabilere Einzelmolekülkontakte mit einer größeren Spanne der Ruheleitfähigkeit bilden. Die Stabilität dieser Geometrien wurde in zeitabhängigen Leitfähigkeitsmessungen gezeigt. Stäbchenförmige Moleküle dagegen haben eine bevorzugte Bindungsgeometrie.

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Rigid molecular tweezers are compounds of increasing scientific interest. As the structural requirements for such compounds are highly specific, few types of these tweezers are thus far known. The preparation of examples of rigid large-pincered molecular tweezers based on bis Troger's bases derived from 1,4-benzenediamine is described. In addition, evidence is presented of the different binding abilities of the diastereoisomers of such compounds.