DETECTING A TRANSITION-METAL AMMINE AT TAILORED SURFACES

The fabrication of surfaces by forming Langmuir films, which incorpora te amphiphiles containing hydrophilic 18-crown-6(18C6) derivatives, at a gas/water interface is described. These Langmuir films can be trans ferred to a hydrophobised quartz crystal microbalance (QCM), using the Langmuir-Blodgett technique. The QCM response has been measured in aq ueous solution as a function of the concentration of the transition me tal complex [Co(NH3)(6)]Cl-3 which was injected into a vial in which t he film-coated QCM had been immersed. By comparing various surfaces co vered with hydrophilic polyether and hydroxy functions and hydrophobic methyl groups, and by varying the composition of the films so as to i ncrease the separation between the 18C6 macrocycles, it has been demon strated that surfaces can be tailored that will enhance the binding of the [Co(NH3)(6)](3+) trications.