1,8-Naphthyridine-Derived Ni²⁺/Cu²⁺-Selective Fluorescent Chemosensor with Different Charge Transfer Processses

Abstract

A highly fluorescent chemosensor based on 1,8-naphthyridine with high sensitivity and selectivity toward Ni(2+)/Cu(2+) over other cations both in aqueous solution over a wide pH range (4-10) and in cellular environments was developed. Counteranions such as acetate, sulfate, nitrate, and perchlorate have no influence on the detection of such metal ions. Ethylenediamine showed high selectivity toward the in situ-prepared Cu(2+) complex over the Ni(2+) complex, which can be applied to distinguish Ni(2+) and Cu(2+). The Ni(2+)-induced fluorescence on-off mechanism was revealed to be mediated by intramolecular charge transfer from the metal to the ligand, while that by Cu(2+) involves intramolecular charge transfer from the ligand to the metal, as confirmed by picosecond time-resolved fluorescence spectroscopy and time-dependent density functional theory calculations.

HCHO-reactive molecule with dual-emission-enhancement property for quantitatively detecting HCHO in near 100% water solution

“…The 2-amidyl-3-(3-amidly-1H-benzo[d]imidazolyl)-pyridine (1) was synthesized according to Scheme 1 and following our recently reported method [33,34].…”

“…The fluorescence decay behavior is shown in Fig. S2, and the fit results are summarized in Table 1 The dual emissions may be attributed to the excited normal (N*) and tautomer (T*) forms which result from an ESIPT (N*→T*) process (Scheme S1) [34].…”

1,8-Naphthyridine and 8-hydroxyquinoline modified Rhodamine B derivatives: “Turn-on” fluorescent and colorimetric sensors for Al3+ and Cu2+

“…7-Acetamidyl-4-methyl-1,8-naphthyridine-2-aldehyde was synthesized according to the method reported [35]. The chemosensors were synthesized according to the route as shown in Scheme 1 and modified methods [33,48,49].…”

N-(7-Dibromomethyl-5-methyl-1,8-naphthyridin-2-yl)acetamide–pyrrolidine-2,5-dione (1/1)

“…For similar structures, see: Li et al (2011). For applications of similar compounds, see: Samadi et al (2011); Li et al (2012); Tanaka et al (2012). For information on their synthesis, see: Henry & Hammond (1977); Wang et al (2008).…”