By changing the ratio of reactants, two mononuclear Dy complexes, [Dy(phen)(acac)(3)] (1) and [Dy(phen)(2)(NO(3))(2)(acac)]·H(2)O (2) have been synthesized and structurally characterized. In 1, a Dy atom bearing square-antiprism coordination geometry exhibits SMM behaviour, while compound 2 with a bicapped-square-antiprism geometry does not show such SMM properties. The different magnetic behaviours seen in 1 and 2 are probably due to a different coordination environment and ligand field around the Dy(III) ions. The results proved the important influence of the structural environment of a SMM on its magnetic behaviour.
A new luminescent Zn(II)-based metal-organic framework (MOF), [Zn(TPOM)(NDC)]·3.5HO (Zn-MOF; TPOM = tetrakis(4-pyridyloxymethylene)methane and Hndc = 2,6-naphthalenedicarboxylic acid), was successfully synthesized by a hydrothermal reaction. The MOF exhibits excellent luminescence emission, and it can detect Fe(III) and Cr(VI) ions with high selectivity, well antiinterference performance, and short response time. In addition, Zn-MOF was selected as a parent coordination compound to encapsulate Eu cations to obtain a Eu-incorporated sample (Eu@Zn-MOF). Subsequently, we explored the potential application of Eu@Zn-MOF as a probe for the selective sensing of Fe(III) and Cr(VI) ions, and it revealed that we could differentiate Fe(III) and Cr(VI) ions by the combination Zn-MOF and Eu@Zn-MOF. More importantly, it represents the first example of MOF-based luminescent sensors which can detect and differentiate Fe(III) and Cr(VI) ions selectively. And the possible sensing mechanism was discussed in detail.
In order to accurately and conveniently measure temperature and water content in bioethanol, a dual-function ratiometric luminescence sensor has been fabricated successfully based on mixed lanthanide metal− organic frameworks (MOFs) Eu 0.02 Dy 0.18 -MOF. In this MOF, the two lanthanides and ligand (H 4 L) form three luminescence centers, and they have different sensitivity toward water and temperature. Using the ratio of luminescence intensity at 416 and 614 nm, the MOF could quantitatively determine the concentration of water in dry ethanol and in bioethanol with recoveries of 91% −107%, and a detection limit of 0.1%, which is much lower than that in hydrated ethyl alcohol fuel (AEHC), 0.8% in China, 1.0% in the United States, and 4.9% in Brazil. Using the luminescence intensity ratio of Eu 3+5 D 0 → 7 F 2 (614 nm) transition to Dy 3+4 F 9/2 → 6 H 13/2 (573 nm) transition, the MOF could also sense temperature in range of 293 to 373 K, and 150 to 290 K with high accuracy, excellent linear relationship, reversibility, and recyclability.
A global international initiative, such as the Earth BioGenome Project (EBP), requires both agreement and coordination on standards to ensure that the collective effort generates rapid progress toward its goals. To this end, the EBP initiated five technical standards committees comprising volunteer members from the global genomics scientific community: Sample Collection and Processing, Sequencing and Assembly, Annotation, Analysis, and IT and Informatics. The current versions of the resulting standards documents are available on the EBP website, with the recognition that opportunities, technologies, and challenges may improve or change in the future, requiring flexibility for the EBP to meet its goals. Here, we describe some highlights from the proposed standards, and areas where additional challenges will need to be met.
A dual-emission hybrid material could detect doxycycline and MnO4− sensitively. Test paper was regarded initially as a tool for doxycycline visual detection. A lower LOD of MnO4− showed that carbon dots can accelerate quenching speed of MOF(Eu).
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