Structure with three-dimensional boron networks

Borides with three-dimensional boron networks. The major types have formulae MB4, MB6 and MB12. MB4 compounds may be of several types insofar as structural details are concerned. ThB4 and CeB4 contain rather... 

Figure 9 The crystal structure of LaBe. The boron atoms (small circles) form a three-dimensional rigid network with s 0.1 A shorter bonds between the octahedra than within the octahedra...

Zinc carboxylate interactions have been exploited as part of a fluorescent molecular sensor for uronic acids. The sensors feature two interactions coordination of the carboxylate to the zinc and a boronic acid diol interaction.389 Photoluminescent coordination polymers from hydrothermal syntheses containing Zn40 or Zn4(OH)2 cores with isophthalate or fumarate and 4,4 -bipyridine form two- and three-dimensional structures. Single X-ray diffraction of both dicarboxylates identified the network structure.373... 

Perhaps as many as twenty other MB4 compounds have the same structure. The MB6 structure is fairly easy to visualize with the help of Fig. 8-2 it can be thought of as a CsCl structure, with B6 octahedra in place of the Cl - ions however, the B6 octahedra are closely linked along the cube edges, so that the boron atoms constitute an infinite three-dimensional network. The MB12 compounds also have cubic structures consisting of M atoms and B]2 cubo-... 

Beyond planar sheet assemblies, three-dimensional COFs have also been synthesized. The tetrahedral boronic acids used to create porous, hydrogen bonded networks were condensed with 2,3,6,7,10,11-hexahydroxytriphenylene to produce COF-105 and COF-108 (Fig. 35). The resulting materials have a cubic structure with an open pore system. It is interesting that these two COFs do not have identical structures, even though they differ only in that COF-105 has a carbon tetrahedral center and COF-108 has a silicon atom at the tetrahedral centers. While no surface area measurements were reported for these boronate COFs, they were reported as low-density crystals with densities of 0.17 to 0.18 g/cm. ... 

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