In this paper, we report a simple, rapid and selective colorimetric visualization of arsenic using unmodified gold nanoparticles (AuNPs) and a phytochelatin-like peptide (γ-Glu-Cys)₃-Gly-Arg (denoted as PC₃R). Arsenic prevented the peptide from attaching to the surface of AuNPs by coordinating to all the three cysteine residues of PC₃R, thus preventing the PC₃R-triggered AuNPs aggregation and color change. The present approach is selective to arsenic detection and is much faster and simpler than the conventional analytical methods. The detection limit is 20 nM, which is lower than the World Health Organization's (WHO) standard for drinking water. The feasibility for the detection of arsenic in groundwater has also been demonstrated. This method will be valuable for the design of new types of metal ions sensors and will likely lead to many colorimetric detection applications in environmental monitoring.

Hydrothermal reactions of Zn(OAc)₂·2H₂O with flexible bipyridyl benzene ligand and three dicarboxylic derivatives gave rise to four new coordination polymers, [Zn₇(μ₄-O)₂(OAc)₁₀(bpmb)]_n (1), [Zn(5-OH-1,3-BDC)(bpmb)]_n (2), [Zn(1,2-BDC)(bpmb)]_n (3) and [Zn₂(ADB)₂(bpmb)]_n (4) (bpmb = 1,4-bis(pyridine-3-ylmethoxy)benzene, 5-OH-1,3-H₂BDC = 5-hydroxy-1,3-benzenedicarboxylic acid, 1,2-H₂BDC = 1,2-benzenedicarboxylic acid, H₂ADB = 2,2’-azodibenzoic acid). Their structures were characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). Compound 1 features a one-dimensional (1D) chain structure based on the rare heptanuclear [Zn₇(μ₄-O)(μ₃-OAc)₂(μ₂-OAc)₈] units. Compound 2 exhibits a novel 2D bilayer structure built from the two parallel 2D (4,4) layers. Compound 3 holds a 2D structure in which the 1,2-BDC ligands work as lockers interlocking 1D [Zn(bpmb)]_n chain. Compound 4 comprises a 3D framework constructed by 2D wrinkled [Zn₂(ADB)₄]_n networks and bpmb linkers with a six-connected pcu net. These results suggest that the motifs of the dicarboxylic ligands have significant effect on the final structures. These compounds exhibited relatively good photocatalytic activity towards the degradation of methylene blue (MB) in aqueous solution under a Xe lamp irradiation.

Solvothermal reactions of AgNO₃ with 9,10-anthraquinone-1,5-dicarboxylic acid (H₂L) and 4,4'-bipyridine (bipy) gave rise to a metal-organic framework, namely [Ag(L)(bipy)]_n (1), which was structurally characterized by elemental analyses, IR spectra, and X-ray diffraction analysis. Single-crystal X-ray diffraction analyses indicate that 1 exhibits a 2D 4⁴ topology framework assembled by dinuclear [Ag₂(COO)₂] units, L and bipy ligands. 1 displays highly sensitivity in the detection of nitrobenzene (NB) as a fluorescent sensor. Moreover, 1 exhibits a relatively good photocatalytic activity towards the degradation of rhodamine B (RhB) in aqueous solution under UV irradiation.

A new strategy for preparing amphibious ZnO quantum dots (QDs) with blue fluorescence within hyper-branched poly(ethylenimine)s (HPEI) was proposed in this paper. By changing [Zn²⁺]/[OH⁻] molar ratio and heating time, ZnO QDs with a quantum yields (QY) of 30% in ethanol were obtained. Benefiting from the amphibious property of HPEI, the ZnO/HPEI nanocomposites in ethanol could be dissolved in chloroform and water, acquiring a QY of 53%, chloroform and 11% in water. By this strategy, the ZnO/HPEI nano-composites could be applied in not only in optoelectronics, but also biomedical fields (such as bio-imaging and gene transfection). The bio-imaging application of water-soluble ZnO/HPEI nanocomposites was investigated and it was found that they could easily be endocytosed by the COS-7 cells, without transfection reagent, and they exhibited excellent biological imaging behavior.

A new strategy for in situ preparation of highly fluorescent CdTe quantum dots (QDs) with 3-mercaptopropionic acid (MPA) and hyperbranched poly(amidoamine)s (HPAMAM) as co-stabilizers was proposed in this paper. MPA and HPAMAM were added in turn to coordinate Cd2+. After adding NaHTe and further microwave irradiation, fluorescent CdTe QDs stabilized by MPA and HPAMAM were obtained. Such a strategy avoids the aftertreatment of thiol-stabilized QDs in their bioapplication and provides an opportunity for direct biomedical use of QDs due to the existence of biocompatible HPAMAM. The resulting CdTe QDs combine the mechanical, biocompatibility properties of HPAMAM and the optical, electrical properties of CdTe QDs together.