Tentative identification of reactive species in the interfacial and aqueous solution synthesis of titanium polymers

Polymer ◽  
1974 ◽  
Vol 15 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Charles E. Carraher ◽  
Samuel T. Bajah
Keyword(s):  
Aqueous Solution ◽  
Reactive Species ◽  
Solution Synthesis ◽  
Tentative Identification

Ambident nucleophiles. II. Nitrogen-bonded and carbon-bonded σ-complex formation in the reaction of pyrrolide anions with 1,3,5-trinitrobenzene

1982 ◽  
Vol 60 (15) ◽  
pp. 1988-1995 ◽  
Author(s):  
J. C. Halle ◽  
M. J. Pouet ◽  
M. P. Simonnin ◽  
F. Debleds ◽  
F. Terrier
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Rate Constant ◽  
Order Rate Constant ◽  
Reactive Species ◽  
Second Order ◽  
Potassium Salts ◽  
Strong Base ◽  
Order Rate

Reaction of 1,3,5-trinitrobenzene (TNB) with pyrrole, 2,5-dimethyl pyrrole, and 2,4-dimethyl-3-ethyl pyrrole in the presence of a strong base (CH3O−) yields nitrogen- and/or carbon-bonded 1:1 σ-complexes in dimethylsulphoxide (DMSO). Depending on the stoichiometry of the reagents, 1:2 and 2:1 pyrrole–TNB diadducts are also formed. Identification of all complexes was effected by nmr. The reactive species are shown to be the pyrrolide ions and the results emphasize the ambident character of these anions towards an aromatic electrophile. Some of the complexes have been isolated as crystalline potassium salts when experiments are performed in acetonitrile. Among the isolable complexes, the kineticallybutnotthermodynamicallyfavored nitrogen adduct of pyrrole (5a) is remarkably unreactive. The second-order rate constant kH+ for is H+-catalyzed decomposition in aqueous solution is only 1 L mol−1 s−1 (t = 25 °C).

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