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Spectroscopic, thermodynamic and kinetic properties of molecular interactions between indolizines and tetracyanoethylene are reported. The interactions involved in the complexes are weak as evidenced by the low formation constants. The kinetic behaviour indicates the initial formation of a pI-complex that is rapidly transformed into a σ-complex and thereafter into the final adduct(s). Apart from the results obtained by other techniques, infrared data clearly evidence vibrational contributes characteristic of the complexes, the tricyanovinyl derivatives and the tetracyanoethylene radical anion.

Spectroscopic, thermodynamic and kinetic properties of molecular interactions between indolizines and tetracyanoethylene are reported. The interactions involved in the complexes are weak as evidenced by the low formation constants. The kinetic behaviour indicates the initial formation of a pI-complex that is rapidly transformed into a σ-complex and thereafter into the final adduct(s). Apart from the results obtained by other techniques, infrared data clearly evidence vibrational contributes characteristic of the complexes, the tricyanovinyl derivatives and the tetracyanoethylene radical anion.

2-Phenyl-3-phenylimino-3H-indole reacts with indole, 2-methylindole and 1,2-dimethylindole in the presence of stoichiometric trichloroacetic acid to form 1,2-dihydro-2-phenyl-2-(indol-3-yl-derivatives)-3-phenylimino-3H-indole, which during a longer period of time (16 hours) undergoes indolyl transposition to carbon-3 and elimination of aniline affording the 3,3′-bis-indolyls. In the case of 1,2-dimethylindole the intermediate coming from the indolyl migration may undergo a nucleophilic addition to carbon-2 of another molecule of indole; the new intermediate leads to the formation of 2-phenyl-3,3′-di-(1,2-dimethylindol-3-yl)-3H-indole by elimination of aniline and migration to carbon-3 of the second molecule of indole. By treatment with hydrochloric acid in refluxing ethanol, 1,2-dihydro-2-phenyl-2-(indol-3-yl-derivatives)-3-phenylimino-3H-indole afford to 3,3′-bis-indolyls and 1,2-dihydro-2-phenyl-2-(indol-3-yl-derivatives)-3H-indol-3-one (indoxyls). The crystal structure of 1,2-dihydro-2-phenyl-2-(indol-3-yl)-3-phenylimino-3H-indole is also reported. The latter compound does not give rearrangement products by acid treatment, only untreatable tarry material.

The reaction of isomeric arylazopyridines with 1-hydroxy-2-phenylindole leads to molecular associations between the pyridine derivative and the 1-hydroxy-2-phenylindole itself or its dimer. The role of hydrogen bonding in the formation of the complex is also discussed in the light of conductivity measurements.

Competitive demethylation and redox reactions induced by 2,2′-diphenyl-Δ3,3′-bi-3H-indole-1,1′-dioxide,1 (dinitrone) on several nitrogen bearing compounds (pyridines, amides, indoles, hydrazones and amines) are reported.