Coordination polymer networks

Note 2 Examples of polymer-supported catalysts are (a) a polymer-metal complex that can coordinate reactants, (b) colloidal palladium dispersed in a swollen network polymer that can act as a hydrogenation catalyst. 

Scheme 6 represents coordinate polymers. A low-molecular-weight compound with multidentate groups on both ends of the molecule grows into a linear polymer with metal ions, and the polymer chain is composed of coordinate bonds. The parquetlike polymer complexes, poly(metal-phthalocyanine) and poly(metal-tetracyano-ethylene), are classified into Scheme 7. They are formed by inserting metal ions into planar-network polymers or by causing a low-molecular-weight ligand derivative to react with a metal salt and a condensation reagent.

Figure 10.1 Time-temperature map. Shape of main boundaries for linear or network polymers. (I) Glassy brittle domain B, ductile-brittle transition. (II) Glassy ductile domain G, glass transition. (Ill) Rubbery domain. The location of the boundaries depends on the polymer structure but their shape is always the same. Typical limits for coordinates are 0-700 K for temperature and 10-3 s. (fast impact) to 1010 s e.g., 30 years static loading in civil engineering or building structures. Fpr dynamic loading, t would be the reciprocal of frequency. For monotone loading, it could be the reciprocal of strain rate s = dl/ Idt.

Rottgers and Sheldrick have recently reported that l,10-dithia-18-crown-6 1 formed lamellar coordination polymer with Cul and ion-ligating iodocuprate(i) based on two-dimensional coordination networks with Cul and alkali metal cations <2000MI271>. Both anionic frameworks contain characteristic iodocuprate(l) chains that are bridged in a /r-Sl,S10 manner by 1. However, the structure-directing influence of the alkali metal cation manifests itself in both the connectivity pattern and the stoichiometry of the resulting Cul-based network. 

Molecularly imprinted polymers (MIPs) may be prepared according to a number of approaches that are different in the way the template is linked to the functional monomer and subsequently to the polymeric binding sites (Table 5.1) (see Chapter 4). Thus, the template can be linked and subsequently recognised by virtually any combination of cleavable covalent bonds, metal ion coordination or non-covalent bonds. The first example of molecular imprinting of organic network polymers introduced by Wulff (see Chapter 4) was based on a covalent attachment strategy, i.e. covalent monomer-template, covalent polymer template [1]... 

Mochida and co-workers have constructed coordination networks by using ferrocene-based bidentate ligands, 1,1 -(4-dipyridinethio)ferrocene and l,l -(2-dipyridinethio)ferrocene. In order to obtain coordination polymers, these... 

Lin and coworkers extended their method to the synthesis of chiral coordination polymers based on the use of rigid bridged ligands derived from the 1,1 binaphtyl framework. Thus homochiral porous coordination networks were prepared however this work will be reviewed in the next chapter of this book. ... 

Self-assembled coordination supramolecular structures encompass both discrete and polymeric types in a range of synthetic areas. Although coordination polymers, two- and three-dimensional coordination networks, polynuclear metal clusters (with primarily metal-metal or /r-oxo or... 

For example, numerous materials such as coordination networks [21] and inorganic crystals consist of layered structures [22], wherein each layer-when considered separately - fulfills the above criteria to be classified as a 2-D (supramolecular) polymer. There are, however, strong forces between layers, so that in most cases these equilibrium 2-D networks are unlikely to be separable (in intact form) one from another. In this chapter, however, attention is focused on the preparation of individual 2-D structures and not on 3-D layered systems the latter would need to be taken apart in a separation step in similar fashion to graphite (i.e., layered graphene) and some other inorganic laminar crystals (see Section 28.5.1) [23]. In a sense, these layered 3-D bulk materials went a step too far, unless isolation of the individual 2-D layers was feasible. 

The chelation leads to a pseudocyclization whereby a coordination network is formed. The structure shown in Equation (28-49) is therefore only one of many possibilities. According to the nature of the metal ion and the molar ratio of metal/PTO, the color varies between yellow (Zr /PTO = 0.35) through orange (Zn /PTO=2) and olive green (Cu /PTO = 0.66) to brown (Ca /PTO = 1) and black (Fe /PTO = 1). White and blue shades are not obtained. The chelated polymers are very flame resistant, especially when chelated with zinc, tin, or iron ions. Mercury ions produce radiation-proof but not fire-proof polymers. 

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