Improving and Fining of Nanostructures by Mixing W with Mo in Metal Organic Hybrid Crystal

Abstract

A bialloy-like multilayered bulk single crystal consisting of [(CH 3 CH 2 ) 3 NH)] 2 [W 0.25 Mo 0.75 O 2 (C 14 H 6 O 4 ) 2 ] has been synthesized, from which Mo−W-mixed organic hybrid nanotubes with a diameter of about 50 nm and length from tens to hundreds of nanometers were prepared by grinding and ultrasonication. The nanotubes possess the uniformity of Mo-based nanopipes and the rigidity of W-based nanotubules and are more delicate and standardized than W-based nanotubules and shorter than Mo-based nanopipes. Furthermore, the Mo−W-mixed nanotubes are disassembled into Mo-based nanowires with a diameter of about 5 nm and lengths in tens of nanometers and W-based nanoparticles with a diameter of 6 nm, which are much finer than the nanoarchitectures produced from Mo-and W-based crystal isomorphs. This research offers two new methods: one is the improvement of nanostructures in physical properties and morphologies by bialloy-like treatment, and another is the refinement of nanostructures compared with those made from crystal isomorphs based on one kind of metal, by mixing metals in a crystal lattice. ■ INTRODUCTIONIn 1992, Tenne et al. reported polyhedral and cylindrical nanostructures assembled by WS 2 1 and nested fullerene nanostructure integrated by MS 2 (M = Mo or W), 2 and a series of nanostructures assembled by Mo, W, and other metal inorganic compounds were successfully synthesized; 3−5 in particular, Mo/W-based inorganic nanostructures play a key role in medical science, 6 magnetism, 7 catalysis, 8 materials, 9−13 and so on. However, in contrast to inorganic nanomaterials, Mo/W-based organic hybrid nanomaterials are seldom reported, which might be because organometal hybrid materials are more easily destroyed under higher temperatures and crucial experimental conditions. For example, organometal hybrid molecules are more easily decomposed under the irradiation of electron beam of transmission electron microscopy (TEM). Moreover, the electron density of metal organic hybrid are much lower than metal inorganic substances, and hence the shapes of the metal organic nanostructures are more difficult to observe than those of metal inorganic nanostructures under TEM. However, the nanoaggregates assembled by metal organic complexes might be very important, which can help us to understand the aggregated state of the complexes in living things. Therefore, we have been focused on studies of Mo-and W-based organic hybrid nanostructures, reported in a series nanostructures assembled by complex [MoO 2 (cat) 2 ] 2− and [WO 2 (cat) 2 ] 2− with diamines, 14,15 and revealed preliminarily the relationships between the dispersed nanomorphologies which disassembled from bulk crystals and the quantum repeating motifs which assembled the bulk single crystals. Also we have synthesized two new isomorphic crystals consisting of [(CH 3 CH 2 ) 3 NH)] 2 -[MO 2 (C 14 H 6 O 4 ) 2 ] (M is Mo or W), from which we prepared two noticeably different Mo-and W-based nanostructures and revealed the mechanism that caused the differences betwee...

Effect of ethylenediamine on the formation of macro, micro, and nanostructures based on [WVI(Cat)2O2]2−

“…However, a controlled and reproducible preparation of such nano-species still needs to be achieved and their formation mechanisms are not yet clarified. In previous papers, [32][33][34][35][36][37][38][39] we designed a series of bulk crystals constructed of Mo-and W-based coordinated structures. Furthermore, by milling and ultrasonication, we disassembled the single crystals into nanowires, nanoparticles, nano-tubules and nanoribbons.…”