pK(a) Switching induced by the change in the pi-conjugated system based on photochromism.
Two diarylethene derivatives 1 a and 2 a containing a 2,5-diaryl-3-thienyl group have been designed and synthesized. The pK(a) values of these compounds change upon photoirradiation. They have a phenol group as a proton source and a pyridinium group as an acceptor unit at each end of the pi-conjugated chain. The cyclization/cycloreversion reactions can be used to control the length of the pi-conjugated chain between the proton source and the acceptor. The change in the pi-conjugated chain length caused the pK(a)-switching.
Odo
Yuka
Y
Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Moto-oka 744, Nishi-ku, Fukuoka 819-0395, Japan.
Matsuda
Kenji
K
Irie
Masahiro
M