Figure 5. Nonlinear fluorescent sensor response measurements of 1 at a controlled relative toluene vapour pressure.

(a) A series of microscopic fluorescent images of 1 under the following relative toluene vapour pressures: 0, 0.2, 1, 2, 5, 7, 9, 10, 11, 13, 15, 17, 19, 20, 30, 50, 70 and 90%. (b) A plot of the RGB fluorescence intensity against the relative toluene vapour pressure in a helium gas stream showing the nonlinear sensor response of the blue and green signals. The data were obtained using the arithmetic mean of 14 samples. The error bars denote the standard deviation. (c) An adsorption isotherm of 1 for benzene with two adsorption steps with hysteresis clearly indicates the cooperative structural transformation in response to guest accommodation.