Molecular tweezer based on zinc porphyrin-substituted diarylethene

A molecular tweezer, zinc porphyrin–dithienylethene–zinc porphyrin (ZnP–DTE–ZnP) triad, has been prepared. Triad ZnPor–DTE–ZnPor showed a little electronic communication among the chromophores judged from the comparison of the steady-state absorption and fluorescence spectra for triads and their component compounds. Irradiation of ZnPor–DTE–ZnPor with UV light converts dithienylethene moiety from open form to closed form. The complexation of ZnP–DTE–ZnP with 4,4′-bipyridyl were investigated by absorption and fluorescence spectroscopic measurements. ZnP–DTE–ZnP forms a 1:1 complex with 4,4′-bipyridyl. The stability constants of log K = 4.0 and 4.2 mol−1 dm3 were determined by absorption and fluorescence spectral changes, respectively.