A comparative study of cryptand-based (triple-head and triple-tail) amphiphiles at the air-water interface

Two cryptands have been derivatized by reacting with acid chlorides of diff erent alkyl chain lengths (between C-4 and C-18) to get a set of cryptand-b ased (triple-head and triple-tail) neutral amphiphiles. The cavity of eithe r cryptand headgroup can accommodate a first-row transition metal ion formi ng stable cryptates. The free as well as the Cu(II)-complexed amphiphiles a re studied at the air-water interface in a Langmuir-Blodgett trough. They f orm 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 L-5 crystallizes in the monocl inic space group P2(1)/c with a 10.091(3) Angstrom, b = 29.994(8) Angstrom, c = 18.174(5) Angstrom, Z = 4, R-f = 0.1048, R-wf = 0.2660, and GOF = 0.92 5. The amphiphile L-6 crystallizes in the trigonal space group P31c: with a = 15.118(2) Angstrom, b = 15.118(2) Angstrom, c = 11.734(2) Angstrom, Z = 2, R-f = 0.033, R-wf = 0.062, and GOF = 0.813. The solid-state structures o f both the amphiphiles show a 3-fold symmetry about a point in the center o f the cryptand headgroup. The hydrophobic tails of the cryptands are packed in the lattice both in interdigitizing and in noninterdigitizing manners.