Secondary building unit approach

Figure 5.17 The secondary building unit approach The binuclear zinc(Il)tetracarboxylate unit will give square planar propagation vectors and the methyltetraphenyl tetrahedral geometry of the net. Together they give the pts net. Note that SUBs and synthons are not synonyms and refer to different ways of disassembling the net in order to plan a synthesis. If you do not feel helped by these concepts you can chose to ignor them for the moment.

CSA controlled secondary building units approach Hjfum... 

The initial transition of dissolved silicate molecules into solid nanoparticles is perhaps the least explored step in the synthesis of zeolites. One impediment to understanding this mysterious step is the poorly elucidated molecular composition of dissolved particles. The major mechanistic ideas for the formation of zeolites approach these structures differently i) many researchers believe that secondary building units (SBU) must be present to form initial nanoslabs [1,2] ii) some others prioritize the role of monomers to feed artificially introduced crystal nuclei or assume that even these nuclei form via appropriate aggregation of monomers [3] iii) silicate solutions are also frequently viewed as random mixtures of various siloxane polymers which condense first into an irregular gel configuration which can rearrange subsequently into a desired crystal nucleus at appropriate conditions [4,5],... 

Approaches to the formation of three new types of micro-porous materials that complement zeolites will be discussed. In each case, whether metal coordination polymers, metal-linked ceramic oxide clusters, or new hybrids containing both coordination and ceramic components, engineering of the Secondary Building Unit (SBU) is of critical importance. Successful examples of these approaches include the first thermally stable 3-D micro-porous coordination polymer with chemical functionalizability [Cu3(TMA)2(H20)3] , as well as a 3-D micro-porous cluster based material [V,2B18O60H8(Cd(en)(H2O) 3]". ... 

Transformations of Molecules and Secondary Building Units to Materials A Bottom-Up Approach... 

The structural architectures of MOFs are mainly dependent on the assembly of metal-containing centers and organic ligands linkers (Fig. 3.1) [24-27]. In spite of wide utilization of single metal ions, it has been recognized that the secondary building units (SBUs) approach offers a prospective avenue toward the rational design and construction of novel MOFs [22]. As a result, the structures... 

An example of a course for lower secondary level school students in England and Wales is Science the Salters Approach (University of York Science Education Group, 1990-1992). This science course for 14 - 16 year olds is an extension of the earlier Chemistry the Salters Approach. Like all the Salters curricula, it develops science concepts from familiar contexts, such as food, clothing and transport. For example, the Construction Materials unit develops concepts relating to chemical structure by considering the properties required for building materials. 

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