One- and two-photon absorption and emission properties of a Zn(II) chemosensor

This paper presents the synthesis and two photon-induced absorption ( TPA) properties of a functionalized distyrylbenzene ( DSB) 1 containing a tetra-azacyclododecane ( cyclen) receptor for Zn( II). The influence of Zn( II) on one- and two-photon absorption characteristics of 1 has been investigated in dimethyl sulfoxide. The experiments show that the TPA action spectrum of uncomplexed 1, at 750 nm employing nanosecond-long excitation pulses, is 5 times more intense than that of the complexed form. This moderate contrast between the bound and unbound species confirms, however, the potential of this design scheme for the development of molecular structures with enhanced sensitivity and contrast to be used as Zn( II) sensors through TPA-induced fluorescence microscopy.