Cation-sensing composite structure and compounds for use therein

A fluorescent ionophoric compound having the general formula:

• ##STR107## wherein m and n are independently 0 or 1;
• Z is O or NH;
• Y and Y' independently are O, S, NH.sub.x, or CH.sub.y where x is 0 or 1 and y is 1 or 2, with the proviso that at least one of Y and Y' must be O, S, or NH.sub.x, each R.sup.2 independently is a sterically non-interferring group;
• R.sup.3 is a non-electron withdrawing group;
• and
• each R.sup.4 group is independently hydrogen, halogen, a hydrocarbyl-containing group, a hetero-acyclic group, a heterocyclic group, or a group having the formula (CH.sub.2 X).sub.c E in which X is O, NH, or a single bond, E is a functional group that includes active hydrogen, and c is a whole number from 0 to 100, or both R.sup.4 groups together with the carbon atoms to which they are attached form a 5- or 6-membered ring which optionally can have one or more further R.sup.4 groups attached,
• wherein the compound has a wavelength of maximum absorbance of at least about 380 nm a wavelength of maximum emission of no more than about 500 nm.

A fluorescent ionophoric compound, comprising

• a complexing moiety for selective binding of an ion;
• and
• a fluorescing moiety that contains close-lying n.pi.* and .pi..pi.* excited states,
• wherein the compound has a wavelength of maximum absorbance of at lest about 350 nm,
• the ionophoric compound having the formula:
• ##STR108## wherein Y is O, S, NH.