New fluorescent ionophores containing 1-pyrenyl aromatic amides based on oligoethylene oxide (1 and 2) have been synthesized and its photochemical behaviors have been studied. In the absence of metal ion, 1-pyrenylbenzamide moiety showed almost no fluorescence emission. However, complexation with Ca2+ induced a large enhancement effect on the fluorescence intensity of 1 and 2 from the pyrene ring. This behavior can be explained by in terms of the similar twisted intramolecular charge-transfer relaxation mechanism.

Two bis(fluorophore) compounds linked by an oxyethylene chain, N, 7,bis(1-anthracenecarboxamide) (1) and N, 7,bis(2-anthracenecarboxamide) (2), were synthesized, and the intramolecular photodimerization of the anthracene units was carried out in acetonitrile solution. The photoproduct ratios of the regioisomers derived from 1 and 2 were quantified in the absence and presence of metal cations. Upon photo-irradiation of 1, three intramolecular photodimers, trans head-to-head dimer D1, cis head-to-head D2 and cis head-to-tail D3, were formed. In the photodimerization of 1, the presence of Ba 2+ enhanced the formation of D1,

Bi-chromophoric compounds linked to linear polyether N, N′-[oxybis(3-oxapentamethyleneoxy-2-phenyl)]-bis(1-anthracenecarboxamide) (14) and its analogues (15, 24 and 25) were synthesized. Their photochemical properties and complexation actions were investigated in acetonitrile. These fluoroionophores have shown weak emissions in the absence of guest ions, resulting in a twisted intramolecular charge transfer (TICT) quenching process (off state) of an anthracene aromatic amide moiety. After the formation of a complex with alkaline earth metal ions, a large enhancement of fluorescent intensities was obtained (on state). The efficiencies of controlling an off-on fluorescent signal using 14 and its analogues (15, 24 and 25) were larger than that of the 9-positioned analogue. These results suggested that the TICT relaxation process was effectively able to control using 14 and its analogues (15, 24 and 25) by complex formations.

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