Switching of ionic and molecular processes

The nature of the ion(s) and the frequency and amplitude coding of ionic pulses may carry and process information, as in biological ionic processes [8.243]. The affinity and selectivity changes in reported bistable photoactivated receptors for ions and molecules are in most cases still quite small, but proper design should provide a range of substances for the photogeneration of ionic and molecular signals. 

Photoprotonic signals can be generated by light induced proton release, this might happen for the quaternary N-R+ derivatives of 117, for instance [8.233]. The photoproduction of proton gradients across membranes could serve as a light-powered proton pump for inducing vectorial processes such as the transport of protons [8.233, 8.234] or H+-ATPase model reactions [8.274]. 

Electroionic signals are generated by electrochemical interconversion of a selective receptor molecule containing a redox-active group (metallocene, quinone, etc.) between states of low and high affinity for a given substrate (see Sections 6.4.1 and 8.3.1). 

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