1.1 -Dimethyl-4,4/-bipyridinium dichloride

Chemicals processed. Waste pesticide solutions were collected after spray operations during late May, June, and July of 1983, and consisted primarily of three compounds 2,4-D [(2,4-dichloro-phenoxy)acetic acid], atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)- -triazine) and paraquat (1,1 -dimethyl-4,4 -bipyridinium dichloride). Our efforts were primarily directed at these pesticides, which are shown in Table I together with their formulations and concentrations. 

Bipvridvls (Diquat (1,1 ethylene-2, 2 -dipyridylium dibromide) Paraquat (1, 1 -dimethyl-4,4 -bipyridinium dichloride))... 

Chemicals Paraquat dichloride (1,1 -dimethyl-4,4 -bipyridinium dichloride) was purchased from Aldrich Co., U.S.A. Stravigen (biotin-streptavidin amplified system (peroxidase)) was purchased from BioGenex Laboratories, U.S.A. 3-Amino-9-ethylcarbozole (AEC) and 3,3 -diaminobenzidine (DAB) were obtained from Sigma Chemical Company, U.S.A. All other reagents were purchased from Nakarai Chemical Co., Japan. 

Dimethyl-4,4 -biphenylene diisocyanate. See Bitoluene diisocyanate 1,1 -Dimethyl-4,4 -bipyridinium. See Paraquat 1,1 -Dimethyl-4,4 -bipyridinium dichloride N,N -Dimethyl-4,4 -bipyridinium dichloride. See Paraquat dichloride... 

Paraquat dichloride (salt) 1, T-dimethyl-4,4 -bipyridinium dichloride... 

The photo-oxidation of the aryl-substituted cycloheptatrienes 7-(/ -methoxy-phenyl)cycloheptatriene and 7-, 1- and 3-(/ -dimethylaminophenyl)cycloheptatrienes to the corresponding radical cations in de-aerated acetonitrile solution was accomplished by electron transfer to the electronically excited acceptors 9,10-dicyanoanthracene, iV-methylquinolinium perchlorate, iV-methylacridinium perchlorate and l,T-dimethyl-4,4-bipyridinium dichloride. In the case of l- p-methoxyphenyl)cycloheptatriene (62), deprotonation of the radical cation occurs successfully, compared with back electron transfer, to give a cycloheptatrienyl radical (63) which undergoes a self-reaction forming a bitropyl. If the photooxidation is done in air-saturated acetonitrile solution containing HBF4 and one of the acceptors, the tropylium cation is formed. Back electron transfer dominates in the / -dimethylaminocycloheptatrienes and the formation of the cycloheptatrienyl radical is prevented. 

Synonyms 1, T-Dimethyl-4,4 -bipyridinium dichloride gramoxone methylviologen... 

Trichloroacetic acid (TCA [81.6 g]) and disodium hydrogen orthophosphate dodecahydrate Na2HP04.12H20 (89.6 g) are dissolved in 600 ml water. Paraquat dichloride (l,l-dimethyl-4,4 -bipyridinium dichloride) (70 ml 36%) is then added, and the solution is adjusted to 1,000 ml with distilled water. The mixture is then cooled on ice to prevent formation of large crystals that are slow to dissolve on thawing and is stored at -15 °C. Extractant A is prepared from 5 ml distilled water adjusted to 1,000 ml with stock solution. Extractant B is prepared by adding 10 ml stock solution (0.1 mM ATP) to approximately 950 ml Extractant A and adjusting to 1 1 with further Extractant A. Normally it is advisable to prepare 51 of stock solution so that the same batch of extractant is used for the complete analysis. 

Figure 9.7 Open-circuit photovoltage vs. solution redox potential for n-Si and p-Si photoelectrodes in 1.0 M KCI/CH3OH solution. The redox couples used were (a) cobaltocene (b) N,N -dimethyl-4,4 -bipyridinium dichloride, (c) N,N -dibenzyl-4,4 -bipyridinium dibromide (d) decamethylferro-cene°, (e) N,N,N, N -tetramethylphenylenediamine , (0 dimethylferrocene, (g) ferrocene , and (h) acetylferrocene °. A tungsten-halogen bulb was used to provide light intensities which yielded short-circuit photocurrent densities of 25-30 mA cm . Source Lewis (1984).

MV, cation radical of l,r-dimethyl-4,4 -bipyridinium dichloride BV+, cation radical of l,l -dibenzyl-4,4 -bipyridinium dibromide Diquaf, cation radical of l,l -ethylene-2,2 -bipyridinium dibromide V 7o, cation radical of 1,1 -propylene-2,2 -bipyridinium dibromide. 

A series of diamide-based cryptands derived from bis(m-phenylene)-[32]crown-10 have been synthesized to complex divalent salts such as paraquat (N,N-dimethyl-4,4 -bipyridinium) dichloride. The synthetic project started from the observation that readily prepared bicyclic crown ether 23 containing two 1,3,5-phenylene units linked by three tetra(ethyleneoxy) units forms a pseudorotaxane-like inclusion complex with Af,Af-dimethyl-4,4-bipyridinium bis(hexafluorophosphate), with an association constant /fa = 6.1 X 1() M that is 100-fold greater than that of the analogous simple crown ether. On this basis, additional anion-binding moieties, such as isophthalamide or 2,6-pyridinedicarboxamide unit, were intfoduced in the third chain of the cryptand receptor. The anion-assisted complexation of bypyridinium dications was analyzed by a combination of different techniques ( H NMR,... 

Paraquat or l,l -dimethyl-4,4 -bipyridinium dichloride Bipyridilium Interrupts photosynthesis, nonselective Orchards, plantations, defoliant for cotton, aquatic weeds 11-1... 

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