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We report here the design and syntheses of a naphthalenediimide (NDI)-N functionalized organic fluorophore, 1, and its supramolecular CT complexes [(1·2H)2+·(PA−)2] (2) and [(1·2H)2+·(3,5-DNSA−)2] (3), self-assembled from 1 as an electron acceptor (A) and picric acid (PA) or 3,5-dinitrosalicylic acid (3,5-DNSA) as a donor (D), with a very large Stokes shift (>170 nm) and significant fluorescence lifetime (∼1.55 ns). NDI is functionalized with phenylpyridyl units (chromophore) to extend the π-conjugation and thus provide a suitable platform for strong C–H---π and π⋯π stacking interactions, which are the prime requirements for any compound to be used as a fluorescent probe. The organic fluorophore, 1, and its supramolecular CT complexes 2 and 3 exhibit decent electronic properties as suggested by DFT, cyclic voltammetry, and fluorescence studies. Moreover, compounds 1–3 were also exploited as fluorescent probes for cell imaging under normal cell isolation and with time-bound exposure. [ABSTRACT FROM AUTHOR]

We report the syntheses and structural characterization of a Zn(II) metallacycle [Zn2{(L)2(DMF)2(NO3)2}]·(NO3)2 (1) along with a Cd(II) coordination polymer [{Cd1(L)2(DMF)2}·(NO3)2]n (2) (where L = N,N′-bis-(3-pyridyl)terephthalamide; DMF = dimethylformamide) and their utilization as fluorescent probes for highly selective recognition (turn-off) of Fe3+ and CrO42− ions. Compounds 1 and 2 were prepared by utilizing ligand L and the nitrate salt of zinc and cadmium, respectively. Single crystal X-ray analysis reveals that 1 adopts an overall Zn(II) metallacycle architecture, whereas 2 displays a one-dimensional (1D) polymeric structure. Both 1 and 2 showed high fluorescence stability in aqueous solution and selectively detected Fe3+ and CrO42− ions with high quenching constants and low detection limits of 2.34 × 106 M−1 and 0.153 μM for Fe3+, 6.72 × 105 and 0.205 μM for CrO42− (for 1); 3.25 × 106 and 0.193 μM for Fe3+, 6.94 × 105 and 0.155 μM for CrO42− (for 2). Notably, ligand L itself did not display any type of recognition for any ions in DMF as well as in aqueous media. Moreover, 1 and 2 were also employed as heterogeneous catalysts for the ring-opening reaction (ROR) of epoxides with various assorted amines and up to 95% yield (TON, 47.5 and TOF, 11.9 h−1) was observed with perfect regioselectivity in the case of styrene oxide. [ABSTRACT FROM AUTHOR]