Self-association mechanisms in aqueous media: dimerization versus micellization of alkyl-ellipticinium derivatives

Autor: Alain Adenier, Marie-Anne Cordonnier, Marie-Françoise Ruasse, Marc-Antoine Schwaller
Rok vydání: 1993
Předmět:
Zdroj: Journal of the Chemical Society, Perkin Transactions 2. :839
ISSN: 1364-5471
0300-9580
DOI: 10.1039/p29930000839
Popis: Self-association mechanisms in aqueous media of ellipticinium (E), 2-methylellipticinium (2-NME), oxazolopyridocarbazolium (H-OPC), 10-pentyloxazolopyridocarbazolium (10-pentyl-OPC), 2 aminopentyloxazolopyridocarbazolium (2-aminopentyl-OPC) and 2-pentyloxazolopyridocarbazolium (2-pentyl-OPC) acetates have been investigated by spectroscopic and kinetic studies. Whereas E, 2-NME, H-OPC, 10-N-pentyl-OPC and 2-aminopentyl-OPC dimerize by self-stacking, the 2-pentyl-OPC displays micellar behaviour (with a critical micellar concentration of 20 µmol dm–3), as a direct consequence of its amphiphilic character. As regards dimerization, both aliphatic substitution (Kd= 7.6 × 103 and 2.4 × 104 dm3 mol–1 for E and 2-NME, respectively) and extension of the π-electron aromatic system (Kd= 1.4 × 105 and 4.5 × 105 dm3 mol–1 for H-OPC and 10-pentyl-OPC, respectively) significantly increase the dimer stability. From kinetic analysis, dimer stability seems to be controlled mainly by the reverse rate constants which vary from 4.9 × 104 to 1.9 × 103s–1.
Databáze: OpenAIRE