title: Photoswitchable basicity through the use of azoheteroarenes.
abstract: Azoheteroarene photoswitches offer functional advantages over their more conventional azobenzene counterparts by virtue of their heteroaromatic ring(s). Here we report that azobis(2-imidazole) functions as a photoswitchable base due to the additional proton stabilisation that is possible in the protonated Z isomer, facilitated by the basic imidazole nitrogens. This thermodynamic difference in stability corresponds to a 1.3 unit difference in pK(a) values between the E and Z isomers. This pK(a) difference can be used to reversibly control solution pH.
authors.affiliation: Department of Chemistry, Imperial College London, London, SW7 2AZ, UK. m.fuchter@imperial.ac.uk.
authors.forename: Claire E
authors.initials: CE
authors.lastname: Weston
authors.affiliation: Department of Chemistry, Imperial College London, London, SW7 2AZ, UK. m.fuchter@imperial.ac.uk.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Richardson
authors.affiliation: Department of Chemistry, Imperial College London, London, SW7 2AZ, UK. m.fuchter@imperial.ac.uk.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Fuchter