Luminescent properties and photo-induced electron transfer of naphthalimides with piperazine substituent

The design and synthesis of a novel 1,8-naphthalimide PAMAM light-harvesting dendron with fluorescence “off-on” switching core

“…With a view to obtain a similar light harvesting antenna, but with ''off-on'' PET based chemosensing core, we used 4-(N-methylpiperazinyl)-1,8-naphthalimide as a ''focal'' (acceptor) dye. The 4-(N-methylpiperazinyl)-1,8-naphthalimides are well known PET chemosensors based on the ''fluorophore-spacer-receptor'' format, which display highly sensitive fluorescence signalling in the presence of various guests cations[58][59][60].The synthesis of amino-terminated 1,8-naphthalimide dendron 5 was performed in four steps following Scheme 2. First, the amino-terminated 1,8-naphthalimide 2 was synthesized as we described before[54] by reaction of 4-bromo-1,8-naphthalic anhydride 1 with ethylenediamine in water at 75 C. The intermediate 2 was subsequently converted into the yellow-green emitting dendron core 3 by reaction with N-methylpiperazine in DMF at 90 C for 4 h in the presence of CuSO 4 $5H 2 O.…”

A Photo-Induced Electron Transfer Based Chemosensor for the Selective Detection of Zn2+ Ions

“…Several probes for Zn 2+ and Cu 2+ have been reported [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] with 4-amino-1,8-naphthalimide as the signalling moiety, but none of them are useful for detection of both the metal ions on duel "off-on" or "on-off " modes. Generally, the fluorescence of 4-piperazino-1,8-naphthalimide derivatives is quenched due to PET arising from the piperazine nitrogen [32][33][34][35]. In the present study, binding of a Zn 2+ ion quenches the PET process, resulting in the fluorescence emission from the chemosensor.…”

“…The fluorescence of 4-piperazino-1,8-naphthalimide derivatives are usually quenched either completely or partially due to PET [32][33][34][35]. During our screening experiments involving different solvents and metal ions, probe 1 showed significant quantum of fluorescence in aqueous and non-aqueous media indicating partial quenching due to PET process.…”

Synthesis and characterization of naphthalimide-functionalized polynorbornenes

“…4 was then alkylated using paraldehyde in formic acid [30, 31] which led to 2-(2-hydroxyethyl)-6-(4-methylpiperazin-1-yl)-1 H -benzo[ de ]isoquinoline-1,3(2 H )-dione ( 5 ), see Scheme 1.…”