Mo- and W-Based Organic Nanostructures Prepared from Bulk Crystal Isomorphs Consisted of [(CH₃CH₂)₃NH)]₂[MO₂(C₁₄H₆O₄)₂] (M = Mo, W)

Abstract

Two new crystal isomorphs consisting of complexes [(CH3CH2)3NH)]2[MoO2(C14H6O4)2] (1) and [(CH3CH2)3NH)]2[WO2(C14H6O4)2] (2) have been synthesized, respectively, and from which Mo-based flexible and durable nanopipes with diameters of 16 nm and lengths of hundreds of micrometers and W-based rigid and fragile nanotubules with ununiform diameters ranging from 30 to 100 nm and lengths in tens of micrometers have been prepared separately, which revealed that the change of the metal in the coordination center of the isomorphs can result in obvious variation to their nanostructures. The crystals both exhibited multilayered structures by the piling of lamellar repeating motifs through van der Waals forces, which are formed by the parallel alignment of 1D chains through hydrogen bonds, and the 1D chains are assembled by complexes 1 and 2, respectively, through geometrical intercalation and π-π packing. However, under grinding and ultrasonication, crystal 1 disassembled uniformly into longer and narrower nanostrips, whereas crystal 2 were broken at random into shorter and wider nanoribbons; therefore, the two lamellar nanostructures curled into different cylindrical nanospecies. The differences caused by Mo and W are the following: the Mo complex prefers to assemble into more durable one-dimensional structures along Mo-O bonds than W isomorphs; since Mo-O bonds are weaker than Mo═O and W-O bonds, then the weakest Mo-O bonds can be supported by the adjacent molecules through intercalation and π-π packing, which resulted in that the linkages among the Mo complexes are stronger along the Mo-O direction and hence the longer Mo-based cylindrical structure. Moreover, the flexibility of Mo-based nanopipes and the rigidity of W-based nanotubules might be attributed to that Mo possesses a lower melting point than W; therefore, Mo is softer and W is harsher.

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

“…On the basis of that the contrast of the shapes of nanostructures on TEM image is associated with the electron densities of the nanosubstance, whereas the electrons of Mo atom are only a half of those of W; molybdenum complexes are easier to assemble into a one-dimensional structure than its tungsten isomorphs, 16 and the same kind of complexes with same bond lengths and angles prefer to aggregate together, similar to the saying that birds of the same feather flock together; it is suggested that the pale one-dimensional nanowires are assembled by [(CH 3 . To reveal the mechanism of the formation of the Mo−W-mixed nanostructures, we determined the bulk single Mo−W-mixed crystal structure.…”

“…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 between the Mo-and W-based nanostructures. 16 Herein, we synthesize the Mo−W-mixed bulk single crystal consisting of [(CH 3 CH 2 ) 3 NH)] 2 [Mo 0.75 W 0.25 O 2 (C 14 H 6 O 4 ) 2 ], for the improvement of the metal organic nanomaterials in structures and physical properties because usually Mo is mixed with W into a bialloy for better application in industry. Also we prepared Mo−W-mixed nanotubes which possess the features of both the Mo-and W-based nanomaterials from the Mo−Wmixed bulk crystal.…”

Synthesis and nanostructure of [Mo(C 6 H 4 O 2 ) 3 ]·2(C 4 H 8 N 2 O) and the synthesis from 1,2-PDA to (C 4 H 8 N 2 O)

“…[20][21][22][23][24][25][26] By grinding and ultrasonication, we disassemble the single crystals into nanostructures with varieties of morphologies, such as nanowires, nanoparticles, nano-tubules and nano-ribbons. Espe-cially, we have prepared different nanostructures from bulk crystals [ [28] , that combined with protonated 1,2-DPA, and demonstrated that the morphologies of the nano-aggregates are associated with the quantum motifs in their crystal lattices; for instance, the quantum-spots induced the formation of nanoparticles, quantum-wire lured the production of nano-ribbons, etc.…”

Supported NiW catalysts with tunable size and morphology of active phases for highly selective hydrodesulfurization of fluid catalytic cracking naphtha

“…Due to their superior optical, electronic, and magnetic properties, one-to three-dimensional W-based organic-inorganic hybrid materials have received extensive attention and have been synthesized by hydrothermal/solvothermal methods [20][21][22], among which the intercalation method is most widely used [22]. However, the above methods involve a high reaction temperature, a long reaction time, or the use of WCl 6 [W(CO) 6 ] as the W precursor [20,21].…”

“…However, the above methods involve a high reaction temperature, a long reaction time, or the use of WCl 6 [W(CO) 6 ] as the W precursor [20,21].…”