Pyridiniumgeminisurfactants with hexadecyl chains linked to nitrogen atoms and a tuned aliphatic spacer that bridges the two pyridinium polar heads in 2,2'-positions have been synthesized and characterized. A multitechnique approach allowed us to study the aggregation behavior, using conductivity, surface tension, and fluorescence. Graphs of the specific conductivity (κ) versus the surfactant molar
A series of fluorinated geminipyridinium amphiphiles have been prepared, purified and fully characterized. The synthesis was performed using alkyl trifluoromethanesulfonates as the quaternizing agents, provided very good yields and overcame problems arising with other less powerful alkylating agents. The use of different characterization techniques, such as conductivity and surface tension measurements
A new series of pyridinium cationic gemini surfactants was prepared by quaternization of the 2,2'(alpha,omega-alkanediyl)bispyridines with N-alkylating agents, whose reactivity is briefly discussed. Particularly useful was the use of long-chain alkyl triflates (trifluoromethanesulfonates) for both overcoming the sterical hindrance in the pyridines and obtaining higher synthetic yields. Well-known 4,4'-(alpha,omega-alkanediyl)bis(1-alkylpyridinium) structures showed narrow temperature ranges for practical applications, due to their high Krafft points, while the new 2,2'-(alpha,omega-alkanediyl)bis(1-alkylpyridinium) series, accounted for good surface active properties. Due to the Krafft points below 0 degreesC, they could be exploited as solutions in water at any temperature. The characterization of the behavior of the series was performed by conductivity measurements. Some of the proposed structures exhibited unusual surface active behavior, which was interpreted in terms of particular conformational arrangements.
Bianchetti, Farmaco, Edizione Scientifica, 1956, vol. 11, p. 346,353