Ethylammonium iodide

Ethynylpyridines are reducible polarographically [382] in a medium containing tetra-ethylammonium iodide, 2-ethynylpyridine at —1.72 V, and 2-methyl-5-ethynylpyridine at —2.06 V (SCE). The reduction potentials of the ethynylpyridines are very close to those of the corresponding vinyl compounds [382]. Similar results have been found for benzene... 

A solution of Mo[HB C3H(CH3)2N2 3](NO)I2-C6H5CH3 (0.5 g) and an excess of ethylamine (0.1 mL) in dichloromethane (40 mL) is stirred at room temperature for 0.5 hour during which time the solution becomes deep red. The volume of the solution is then reduced by evaporation (to 20 mL), and diisopropyl ether is added dropwise to produce a white precipitate of ethylammonium iodide. The mixture is then filtered and the dichloromethane is removed from the filtrate by evaporation, causing the crude, red product to precipitate from the diisopropyl ether. This is collected by filtration and recrystallized from dichloromethane/ diisopropyl ether. Yield 0.3 g (78%). Anal. Calcd. for MoC17HMNgBOI C, 34.36 H, 4.72 N, 18.86. Found C, 34.61 H, 4.72 N, 18.61. 

The optimized power conversion efficiency improved from 9.4 + 0.76 to 10.2 + 0.58% after the addition of 0.5% by volume of ethylammonium iodide. These devices exhibit an extremely high stability. 

Chemicals and Solvents. Acetonitrile (Burdick and Jackson) and dichloromethane (Fisher) were stored over Davisson 3 molecular sieves for at least 24 h. before use. Tetra-n-ethylammonium hexafluorophosphate (TEAH) was purchased from Alfa and used without further purification. Tetra-n-ethylammonium perchlorate (TEAP) was prepared from the corresponding bromide salt (Eastman) with the use of a previously published procedure (7). Tetra-n-butylammonium hexafluorophosphate (TBAH) was prepared by dissolving the iodide salt (Eastman) in a hot, equivolume water/ethanol/ acetone mixture followed by addition of HPFg (Alfa). The solution was reduced to approximately half its original volume, then cooled to room temperature. The resulting white solid was filtered off... 

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