Three-periodic nets and tilings: regular and quasiregular nets.

Regular nets are defined as those with symmetry that requires the coordination figure to be a regular polygon or polyhedron. It is shown that this definition leads to five regular 3-periodic nets. There is also one quasiregular net with a quasiregular coordination figure.

One-step synthesis and structure of an oligo(spiro-orthocarbonate).

The reaction of pentaerythritol and tetraethylorthocarbonate at 260 degrees C for 12 h yields a white crystalline material that was characterized by 13C CPMAS NMR, CHN analysis, FT-IR, electron and X-ray powder diffraction, and Rietveld analysis. The white crystalline material was found to have the formula C6H8O4 and a crystal structure with a monoclinic cell [a = 9.167 A, b = 5.

Geometric requirements and examples of important structures in the assembly of square building blocks.

The basic structures for linking squares into polyhedra and networks (reticulation) are enumerated, and corresponding examples are described in which crystals were synthesized by linking paddle wheel (square) units into metal-organic frameworks (MOFs)--named MOF-102 to MOF-112.

Systematic design of pore size and functionality in isoreticular MOFs and their application in methane storage.

A strategy based on reticulating metal ions and organic carboxylate links into extended networks has been advanced to a point that allowed the design of porous structures in which pore size and functionality could be varied systematically. Metal-organic framework (MOF-5), a prototype of a new class of porous materials and one that is constructed from octahedral Zn-O-C clusters and benzene links, was used to demonstrate that its three-dimensional porous system can be functionalized with the organic groups -Br, -NH2, -OC3H7, -OC5H11, -C2H4, and -C4H4 and that its pore size can be expanded with the long molecular struts biphenyl, tetrahydropyrene, pyrene, and terphenyl. We synthesized an isoreticular series (one that has the same framework topology) of 16 highly crystalline materials whose open space represented up to 91.

Cu(2)[o-Br-C(6)H(3)(CO(2))(2)](2)(H(2)O)(2).(DMF)(8)(H(2)O)(2): a framework deliberately designed to have the NbO structure type.

The synthesis of an NbO-type metal-organic framework was achieved by design: o-Br-BDC (BDC = benzenedicarboxylate) was used to direct the formation of Cu2(CO2)4 paddle wheel units at 90 degrees to each other and thus yield the target network. The compound was formulated as Cu2[o-Br-BDC]2(H2O)2.(DMF)8(H2O)2 (MOF-101) and characterized by single-crystal X-ray diffraction [cubic, space group Imm (No.

An Open-Framework Germanate with Polycubane-Like Topology.

Body-centered Ge parallelepiped building blocks form the basis of the structure of [Ge O (OH) ]⋅2 (H ppz)⋅0.5 (H O) (ASU-14, ppz=piperazine). In this new structure type for an open-framework germanate (see picture for a section of the structure) the building blocks are linked together at each of their eight vertices to give the rare polycubane topology with an intersecting channel system of ten- and eight-membered rings (pore sizes 5×6 and 4×4 Å , respectively) in which the piperazinium cations and water molecules reside.