Synthesis and characterization of tri-quinoline based receptors and study interactions with Zn2+ and Cu2+ ions

Sugar-based carboxamidoquinoline conjugate for sensing Cu2+ and Au3+ ions in water through different binding modes and real application

A simple water-soluble carboxamidoquinoline derivative of glucofuranose 1 exhibited reversible selectivity toward Cu2+ and Au3+ ions in different binding modes. Sensor 1 is an example of a dual sensor for identifying copper and gold ions in the water medium. Sensor 1 exhibited excellent selection ability and sensitivity for Cu2+ and Au3+ ions rather than several metal ions and anions with a wide pH range (5-10). The association constants for both ions were determined to be 3.58 × 104 M-1 and 1.84 × 104 M-1, respectively. The 1:1 binding chemistry of the complexes was verified from the Job method and again validated through mass spectra. Sensor 1 can detect Cu2+ and Au3+ ions at very low concentrations, such as 0.014 μM for Cu2+ and 0.058 μM for Au3+. The different sensing strategies of sensor 1 towards Cu2+ and Au3+ were manifested from the photophysical properties of sensor 2 with metal ions, FT-IR spectra, and theoretical (DFT) observations. The useful relevance of the sensor for Cu2+ and Au3+ ions was tested in different water samples.

Intrinsic structural features of coordination polymers make an impact on dye selectivity

Differences in hydrogen-bonded assembly help in recognition of dyes.

6-Polyamino-substituted quinolines: synthesis and multiple metal (CuII, HgII and ZnII) monitoring in aqueous media

Chemoselective palladium-catalyzed arylation of polyamines with 6-bromoquinoline has been explored to prepare chelators for the detection of metal cations in aqueous media. The introduction of a single aromatic moiety into non-protected polyamine molecules was achieved using the commercially available Pd(dba)2/BINAP precatalyst to afford nitrogen chelators, in which the aromatic signalling unit is directly attached to the polyamine residue. Water-soluble receptors were then synthesized using N-alkylation of these polyamines by hydrophilic coordinating residues. By combining rich photophysical properties of the 6-aminoquinoline unit with a high coordination affinity of chelating polyamines and a hydrophilic character of carboxamido-substituted phosphonic acid diesters in a single molecular device, we synthesized chemosensor 5 for selective double-channel (UV-vis and fluorescence spectroscopies) detection of CuII ions in aqueous media at physiological levels. This receptor is suitable for the analysis of drinking water and fabrication of paper test strips for the naked-eye detection of CuII ions under UV-light. By increasing the number of donor sites we also obtained chemosensor 6 which is efficient for the detection of HgII ions. Moreover, chemosensor 6 is also suitable for multiple detection of metal ions because it chelates not only HgII but also CuII and ZnII ions displaying different responses of emission in the presence of these three cations.