Synthesis and Characterization of Zincoxide Nanoparticles of Average Diameter 10nm in Aqueous Medium

Synthesis of Zincoxide nanoparticles (ZnO NPs) with definite size and shape and their morphological characterization rationally is really a challenging aspect at present due to the ongoing demand of these nanosize particles for their divergent use in different field of science and technology. Reduction of Zinc acetate dihydrate by sodium hydroxide was performed to produce ZnO NPs by following precipitation method. Here the whole reaction was completed in aqueous medium in low temperature. To characterize the synthesized ZnO NPs some recent techniques like X-Ray diffraction study (XRD), Ultra-Violet Visible (UV-Vis) spectroscopy, Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Selected area electron diffraction (SAED) and Electron diffraction X-ray (EDX) were used systematically.

Electron Diffraction Study of the Space Group Variation in the Al–Mn–Pt T-Phase

Binary high temperature “Al3Mn” (T-phase) and its extensions in ternary systems were the subjects of numerous crystallographic investigations. The results were ambiguous regarding the existence or lack of the center of symmetry: both Pna21 and Pnam space groups were reported. Our research on the Al–Mn–Pt T-phase allowed concluding that inside a continuous homogeneity region, the structure of the Al-rich T-phase (e.g., Al78Mn17.5Pt4.5) belongs to the non-centrosymmetric Pna21 space group, while the structure of the Al-poor T-phase (such as Al71.3Mn25.1Pt3.6) is centrosymmetric, i.e., Pnam. Following metallurgical and crystallographic considerations, the change in the symmetry was explained.

Entanglement of Square Nets in Covalent Organic Frameworks

Two entangled 2D square COFs have been synthesized from 4,4',4'',4'''-(9,9'-spirobi[fluorene]-2,2',7,7'-tetrayl)-tetrabenzaldehhyde (SFTB) and p-phenylenediamine (PPA) and benzidine (BZD) to form COF-38, [(SFTB)(PPA)2]imine and its isoreticular form COF-39, [(SFTB)(BZD)2]imine. We also report the single crystal electron diffraction structure of COF-39 and find that it is composed of mutually entangled 2D square nets (sql). These COFs represent the first examples of entangled 2D COF structures, which as we illustrate were made possible by our strategy of using the distorted tetrahedral SFTB building unit. SFTB overcomes the propencity of 2D COFs to stack through π-π stacking and allows for entanglements to form. This work adds significantly to the design principles of COFs.