Synthesis, photophysical and iron-sensing properties of terpyridyl-based triphenylamine derivatives

A series of new terpyridyl phenyl/styryl triphenylamine chromophores were designed and synthesized. The branching number and the rigid/flexible bridge structures had a remarkable effect on the photophysical, selectivity and sensitivity for Fe(II) ion properties of these chromophores. The fluorescence lifetimes of the rigid terpyridyl phenyl triphenylamine chromophores are longer than that of the flexible terpyridyl styryl triphenylamine derivatives. The terpyridyl phenyl/styryl triphenylamine chromophores present an increasing fluorescence lifetime with the increase in the number of branches from 1 to 3. The terpyridyl flexible styryl triphenylamine derivatives have a higher sensitivity than that of the terpyridyl rigid phenyl triphenylamine derivatives for Fe(II) ion in neutral aqueous solution amongst other divalent metal ions such as Cu2+, Co2+, Ni2+, Hg2+, Mg2+, Pb2+, Zn2+.

► The new branching terpyridyl triphenylamine chromophores with the bridge of phenyl or styryl group were synthesized.
► The branching number and the rigid/flexible bridge show the remarkable effect on the photophysical properties.
► Chromophores with the flexible structure has higher sensitivity to Fe(II) ion in solution than those with the rigid one.