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A Comparative Study of Cryptand-Based (Triple-Head and Triple-Tail) Amphiphiles at the Air−Water Interface
journal contribution
posted on 1999-12-23, 00:00 authored by Gopal Das, Parimal K. Bharadwaj, U. Singh, R. A. Singh, Ray J. ButcherTwo cryptands have been derivatized by reacting with acid chlorides of different alkyl chain lengths
(between C4 and C18) to get a set of cryptand-based (triple-head and triple-tail) neutral amphiphiles. The
cavity of either cryptand headgroup can accommodate a first-row transition metal ion forming stable
cryptates. The free as well as the Cu(II)-complexed amphiphiles are studied at the air−water interface
in a Langmuir−Blodgett trough. They form stable monolayers at the air−water interface, which can be
transferred onto different substrates (viz., glass, fluorite, and quartz). They form Y-type Langmuir−Blodgett films. The amphiphile L5 crystallizes in the monoclinic space group P21/c with a = 10.091(3) Å,
b = 29.994(8) Å, c = 18.174(5) Å, Z = 4, Rf = 0.1048, Rwf = 0.2660, and GOF = 0.925. The amphiphile L6
crystallizes in the trigonal space group P31c with a = 15.118(2) Å, b = 15.118(2) Å, c = 11.734(2) Å, Z =
2, Rf = 0.033, Rwf = 0.062, and GOF = 0.813. The solid-state structures of both the amphiphiles show a
3-fold symmetry about a point in the center of the cryptand headgroup. The hydrophobic tails of the
cryptands are packed in the lattice both in interdigitizing and in noninterdigitizing manners.