A strategy for creating foldameric oligorotaxanes composed of only positively charged components is reported. Threadlike components-namely oligoviologens-in which different numbers of 4,4'-bipyridinium (BIPY(2+)) subunits are linked by p-xylylene bridges, are shown to be capable of being threaded by cyclobis(paraquat-p-phenylene) (CBPQT(4+)) rings following the introduction of radical-pairing i...

The synthesis and switching properties of two "basket handle" porphyrin isomers is described. The cis-oriented meso-phenyl groups of these porphyrins are linked at their ortho-positons via benzocrown-ether-based spacers, which as a result of slow atropisomerization are located either on the same side of the porphyrin plane (cis), or on opposite sides (trans). In solution, the cis-linked isomer ...

A series of 1-ethyl-1'-benzyl-4,4'-bipyridinium compounds with different counter anions (BEV-X2, where the X is Cl, Br, I, PF6, ClO4) were synthesized. By using of NMR, MS, electrochemistry, Na2S2O4-induced redox chemistry, and UV-Vis, the role of the different counter anions in the host-guest chemistry of cucurbit[8]uril (CB[8]) was studied for the first time. The result demonstrated that BEV-...

Six pyridyl derivatives [benzylviologen, 2-anilinopyridine, l,2-bis(4-pyridyl)ethane, l,2-b is(4pyridyl)ethylene, 2-benzoylpyridine, and 2-benzylaminopyridine] and five heme-iron derivatives [hemoglobin, hemin, hem atin, ferritin, and ferrocene] were screened for their potential to coun­ teract paraquat (l,l'-dim ethyl-4,4'-bipyridinium ion) toxicity on pea (Pisum sativum L.) isolated chloropla...

Paraquat (1,1'-dimethyl-4,4'-bipyridinium chloride, PQ) is a non-selective herbicide, and PQ poisoning by accidental or intentional ingestion is a cause of numerous fatalities around the world every year. Although a great deal of research has been conducted into the development of an acceptable treatment for PQ poisoning, no effective guidelines f...

BACKGROUND Although organoboronic acids are efficient high-throughput sugar sensors, they have not been pursued for gut permeability studies. A modification of the lactulose/mannitol assay is described by which small intestinal permeability is assessed at the time of urine collection using a lactulose/riboflavin ratio. METHODS Volunteers ingested 50mg riboflavin and either 5 g mannitol or 10 ...

The redox potentials of 4,4’-dimethyl-N’N’-alkylidene bridged 2,2’-bipyridinium salts derivatives (DBPAs) can be controlled by changing the N, N’-alkylidene bridge length which changes the conformation of the DBPAs.. In this paper, the torsional angles between the two pyridine rings and the molecular energy of DBPAs are calculated using a PC based software package (AccuModel 1.2). The relations...