An integrated enzyme-functionalized field-effect transistor (ENFET) device for the sensing of nitrate ions is described. An aminosiloxane-functionalized gate interface is modified with N-methyl-N'-(carboxyalkyl)-4,4'-bipyridinium relay units. The complex formed between nitrate reductase and the bipyridinium units on the gate surface is crosslinked with glutaric dialdehyde to yield a stable rela...

Paraquat (1,1_-dimethyl-4,4_-bipyridinium dichloride), is a foliar-applied and non selective bipyridinium herbicides, and it is one of the most widely used herbicides in the world, controlling weeds in a huge variety of crops like corn, rice, soybean, wheat, potatoes; major fruits: apples, oranges, bananas; beverages: coffee, tea, cocoa; and processed crops: cotton, oil palm, sugarcane and rubber.

Z. Naturforsch. 43b, 475-482 (1988); received February 13/October 22, 1987 Electron Transfer Relays, Viologen Derivatives, Bipyridinium Compounds, Stable Cation Radicals, Photoinduced Water Splitting The synthesis of some new bipyridinium salts is described. Their behavior upon reduction is studied by cyclovoltammetry, coulometry and spectroscopically. Halfwave potentials range from —0.28 V to ...

A unique supramolecular helix assisted by water tetramers is obtained by static evaporation of aqueous solution of a zwitterionic salt, 1,1'-bis(4-carboxylatebenzyl)-4,4'-bipyridinium; spontaneous chiral symmetry breaking occurs in crystallization; interestingly, redox chromism behavior of crystals upon exposure to alcohol atmosphere has been observed.

A series of redox-responsive architectures featuring two bipyridinium units introduced onto the lower rim of a calixarene skeleton has been synthesized. The redox-triggered intramolecular dimerization of the reduced bipyridiniums has been investigated by electrochemistry, spectroelectrochemistry and by theoretical chemistry. The spectroscopic signature of the intramolecular dimers was found to ...

There was reason from bacterial and algal systems to expect that pretreatments with a paraquat analog might confer tolerance against a subsequent paraquat treatment. Thus, a series of compounds were tested for protective activity against bipyridinium herbicides. These included other bipyridinium compounds and derivatives, as well as compounds having similar or more positive redox potentials tha...

Four new complex salts [Ru(II)Cl(Tpm)(L(A))2][PF6]n [Tpm = tris(1-pyrazolyl)methane; n = 1, L(A) = pyridine (py) 1 or ethyl isonicotinate (EIN) 2; n = 3, L(A) = N-methyl-4,4'-bipyridinium (MeQ(+)) 3 or N-phenyl-4,4'-bipyridinium (PhQ(+)) 4] have been prepared and characterized. Electronic absorption spectra show intense d → π* metal-to-ligand charge-transfer (MLCT) absorption bands, while cycli...

The rate of electron transfer is critical in determining the efficiency of photoenergy conversion systems and is controlled by changing the relative energy gap of components, their geometries, or surroundings. However, the rate of electron transfer has not been controlled by the remote input of an external field without changing the geometries or materials of the systems. We demonstrate here th...

We have developed a synthetic approach to the self-assembly of [2]-, [3]-, and [4]rotaxanes, incorporating bis-p-phenylene-34-crown-10 as the ring component(s) surrounding bipyridinium-based dumbbell-shaped components bearing dendritic stoppers at both ends. As a result of the hydrophobic dendritic framework, these [n]rotaxanes are soluble in a wide range of organic solvents, despite the polyca...

The reaction of bipyridine with hydroiodic acid in the presence of iodine gave two new polyiodide-containing salts best described as 4,4′-bipyridinium bis(triiodide), C10H10N2[I3]2, 1, and bis(4,4′-bipyridinium) diiodide bis(triiodide) tris(diiodine) solvate dihydrate, (C10H10N2)2I2[I3]2 · 3 I2 · 2H2O, 2. Both compounds have been structurally characterized by crystallographic and spectroscopic ...