LANGMUIR FILMS AND LANGMUIR-BLODGETT MULTILAYERS INCORPORATING MECHANICALLY-THREADED MOLECULES - PSEUDOROTAXANES

This paper describes the synthesis of a pi-electron rich aromatic lipi d containing a polyether thread intercepted by a 1,5-dioxynaphthalene moiety. The terminus of one end of the polyether is a methoxyl group a nd the other a glycerol unit linked via the 2-oxo position, while the 1,3-oxo functions are covalently attached to octadecyl chains. This co mpound, when cospread at the air-water interface with the tetracationi c cyclophane, cyclobis(paraquat-p-phenylene), and the phospholipid, di myristoylphosphatidic acid, as its monoanion, forms self-assembled pse udorotaxanes which are self-organized into a two-dimensional supramole cular array at the interface. The electrostatic interactions between t he tetracationic cyclophane and the monoanions of the phospholipid anc hor the cyclophane to the interface. This anchoring allows the naphtha lene moiety to remain threaded through the cavity of the cyclophane by a combination of charge-transfer and hydrogen-bonding interactions. T hese Langmuir films can, subsequently, be transferred to a quartz supp ort to fabricate Langmuir-Blodgett multilayers. In characterising thes e self-organized systems, surface pressure-area isotherms and surface potential measurements have been used in conjunction with fluorescence and UV-Vis spectroscopies. This research may have implications in sen sor technology and molecular information storage devices.