A novel sensing system has been designed for the detection of cupric ions. It is based on the quenched fluorescence signal of carbon dots (CDs), which were carbonized from poly(vinylpyrrolidone) (PVP) and L-Cysteine (CYS). Cupric ions interact with the nitrogen and sulfur atoms on surface of the CDs to form an absorbed complex; this results in strong quenching of the fluorescence of the CDs via a fast metal-to-ligand binding affinity. The synthesized water-soluble CDs also exhibited a quantum yield of 7.6%, with favorable photoluminescent properties and good photostability. The fluorescence intensity of the CDs was very stable in high ionic strength (up to 1.0 M NaCl) and over a wide range of pH levels (2.0–12.0). This facile method can therefore develop a sensor that offers reliable, fast, and selective detection of cupric ions with a detection limit down to 0.15 μM and a linear range from 0.5 to 7.0 μM (R2 = 0.980). The CDs were used for cell imaging, observed that they were low toxicity to Tramp C1 cells and exhibited blue and green and red fluorescence under a fluorescence microscope. In summary, the CDs exhibited excellent fluorescence properties, and could be applied to the selective and sensitive detection of cupric ion and multicolor cell imaging.

Two new polymeric iodoargentate hybrids induced by rare earth metal complexes and conjugated organic cations, {[Er(DMF)8][Ag6I9]}n (1) and [(MMP)(AgI2)]n (2) (MMP = 1‐methyl‐4‐methylpyridinium) were obtained by the routine synthetic reaction and structurally determined. In compound 1, a (Ag6I9)n3n– chain is defined by edge‐sharing Ag6I12 units, and in 2, the (Ag2I4)n2– chains are constructed by edge‐sharing AgI4 tetrahedra. C–H···I hydrogen bonds between cations and iodoargentate polyanions contribute to their structural extension from 1D to a 2D layer (for 1) and a 3D network (for 2). The UV/Vis spectra indicate that compared with 2, compound 1 exhibits a narrower adsorption scope with an onset at about 360 nm, and it has a much wider bandgap of about 3.50 eV.

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Two new heterometallic complexes, [Bi(phen)I 4 Ag(phen)] n (1) and [Pb(bipy)Ag 3 I 5 ] n (2) (phen ¼ 1,10-phenanthroline, bipy ¼ 2,2 0 -bipyridine), have been synthesized, significant for incorporation of heavy p-block metals (Pb and Bi) into iodoargentate frameworks to get heterometallic complexes. Complex 1 could be described as the combination of Ag(phen)I 4 and Bi(phen)I 4 octahedra by edge-sharing and 2 is constructed from ðAg 3 I 5 Þ 2nÀ n and [Pb(2,2 0 -bipy)] 2þ by Pb-I covalent bonds. Their optical band gaps, fluorescences, and thermal behaviors are also discussed.