Unsymmetrical cell

In cases where an unsymmetrical cell is used (see Figure 4, for examples), it is necessary to insure there exists a uniform representation of all possible... 

Rapson HOC and Bird AE, /. Pharm. Pharmacol, 15,222T (1963). Cited in Perrin Bases Suppl. No. 7777 ref R6. NB Potentiometric titrations used a glass electrode with an unsymmetrical cell and liquid junction potentials. 

NB Data from titrations using a glass electrode in an unsymmetrical cell with liquid junction potentials. Graphical extrapolaticm to zero ionic strength was used. Also reported t = 37,5.595 9.386 t = 50, 5.358 9.047. Numerous other approximate (A) and uncertain (U) values were also reported by Perrin. 

Muller F, Z. Elektrochem., 30,587 (1924). Cited in Perrin Bases 2923 ref. M60. NB The study used potentiometric titration with hydrogen electrodes in an unsymmetric cell with liquid junction potentials. 

Perel man Y, Sb. Nauchn. Tr. Leningr. Khim-Farmatsevt. Inst. 2,38 (1957) CA 54 11382b. Cited in Perrin Bases 2929 ref. P16. NB Unsymmetrical cell with diffusion potentials. 

No reference cited by Perrin. Used glass electrode in an unsymmetrical cell with liquid junction potentials. 

Jaffe HH and Doak GO, The basicities of substituted pyridines and their 1-oxides, fACS, 77,4441-4444 (1955). NB Used a glass electrode in an unsymmetrical cell wiBi junction potentials. 

Bottomley W and Mortimer PI, Partition separation of tropane alkaloids. Aust. /. Client., 7, 189-196 (1954). Cited in Perrin Bases 2939 ref. B86. NB Used a glass electrode in an unsymmetrical cell with liquid junction potentials. See Hyoscyamine for details. 

Hall NF, Sprinkle MR, JACS, 54, 3469 (1932). Cited in Perrin Bases no. 3720, ref. HI6. Used hydrogen/ calomel electrodes in an unsymmetrical cell to measure buffer solutions of fixed concentration ratios. Ref. A69 (Angyal SJ and Warburton WK, Basic strengths of methylated guanidines, CS, 2492-2494 (1951)). Used a glass electrode in an unsymmetrical cell, and gave pKa = 13.4. 

The largest protonated cluster of water molecules yet definitively characterized is the discrete unit lHi306l formed serendipitously when the cage compound [(CyHin)3(NH)2Cll Cl was crystallized from a 10% aqueous hydrochloric acid solution. The structure of the cage cation is shown in Fig. 14.14 and the unit cell contains 4 [C9H,8)3(NH)2aiCUHnOfiiai- The hydrated proton features a short. symmetrical O-H-0 bond at the centre of symmetry und 4 longer unsymmetrical O-H - 0 bonds to 4... 

The synthesis, spectral properties, and applications of symmetrical as well as unsymmetrical, hydrophobic oxo-squaraine probes for noncovalent interaction with proteins, lipids, cells, and other high-molecular-weight analytes are described in numerous publications and patents [52, 57, 58]. 

Heptyl 3-Phenylpropyl Ether [Electrogenerated Acid-Promoted Reduction of an Aldehyde to an Unsymmetrical Ether].333 A mixture of 1-heptanal (1.0 mmol), 3-phenylpropoxytrimethylsilane (1.2 mmol), tetra-n-butylammonium perchlorate (0.1 mmol), and lithium perchlorate (0.1 mmol) was dissolved in CH2CI2 (3 mL) in an undivided cell. The mixture was electrolyzed under constant current (1.67 mA cm-2) with platinum electrodes at ambient temperature. After 5 minutes, dimethylphenylsilane (1.2 mmol) was added drop-wise and the electrolysis was continued (0.06 Faraday/mol). After completion of the reaction, one drop of Et3N was added and the solution was concentrated. The residue was chromatographed on Si02 to give 1-heptyl 3-phenylpropyl... 

Apart from the electrocarbonylation reactions of organic halides described in Sect. 6, other Ni-catalyzed reactions leading to ketones have been reported. Thus the electroreductive coupling between acylchlorides and alkyl halides, catalyzed by NiBr2bpy leads to unsymmetrical ketones [129]. Recently acylchlorides have been converted to symmetrical ketones in an undivided cell fitted with a nickel or stainless steel anode. In this reaction the active metallic species... 

There is a double charge layer at the surface of a metal which has its origin in the unsymmetric distribution of the electronic charge (6). On quantum-mechanical grounds, the electronic charge distribution spreads beyond the limits normally imposed by the presence of adjacent cells in the interior of the metal in order to lower the kinetic energy of the electrons. The consequence is seen in Fig. 7. In Fig. 7a the charge distribution about the sur-... 

Nickel-2,2-bipyridine complexes are also used for the preparation of unsymmetrical biaryls such as 4-methoxy-4 -trifluoromethylbiphenyl by electroreduction of two aryl halides, one of which has electron-donating and the other electron-withdrawing groups in the aromatic ring as shown in equation 110. The reaction was carried out in N-methylpyrrolidinone at constant current in an undivided cell fitted with a sacrificial magnesium anode and excess of 2,2 -bipyridine167. 

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