Alexander B. C. Deutman, Cyrille Monnereau, Mohamed Moalin, Ruud G. E. Coumans, Nico Veling, Michiel Coenen, Jan M. M. Smits, René de Gelder, Johannes A. A. W. Elemans, Gianfranco Ercolani, Roeland J. M. Nolte and Alan E. Rowan
Squaring cooperative binding circles

Abstract:
The cooperative binding effects of viologens and pyridines to a synthetic bivalent porphyrin receptor are used as a model system to study how the magnitudes of these effects relate to the experimentally obtained values. The full thermodynamic and kinetic circles concerning both activation and inhibition of the cage of the receptor for the binding of viologens were measuredand evaluated. The results strongly emphasize the apparent character of measured binding and rate constants, in which the fractional saturation of receptors with other guests is linearly expressed in these constants. The presented method can be used as a simple tool to better analyze and comprehend the experimentally observed kinetics and thermodynamics
of natural and artificial cooperative systems.