Interlocked structures

Alternatively the ion exchanger may be a synthetic polymer, for example a sulphonated polystyrene, where the negative charges are carried on the —SO3 ends, and the interlocking structure is built up by cross-linking between the carbon atoms of the chain. The important property of any such solid is that the negative charge is static—a part of the solid—whilst the positive ions can move from their positions. Suppose, for example, that the positive ions are... 

Takata, T., Kihara, N. and Furusho, Y. Polyrotaxanes and Polycatenanes Recent Advances in Syntheses and Applications of Polymers Comprising of Interlocked Structures. Vol. 171, pp. 1-75. 

The alignment of these predicted OB-fold domains is consistent with a conserved arrangement of the secondary structure elements that are seen in the ModE structure and suggests that all members of this family form an interlocked structure (Fig. 2B,C). Furthermore, secondary structure... 

Mn(ll)Cu(II) magnets, 43 253 molecular-based magnet, three spin carriers with full interlocked structure, 43 199, 201-204 Ni(II)Cu(II)binuclear and... 

In this contribution, we would like to show how such an approach allowed us to synthesize both soft and very hard molecule-based magnets. This contribution is organized as follows first, we define briefly the field of molecular magnetism, then we indicate the successive steps which led us to three-dimensional molecule-based magnets with fully interlocked structures. We describe these original structures in detail. Finally, we focus on the physical properties of these objects, with special emphasis on the huge coercivity of one of the compounds, which confers a memory effect on this compound. 

Structure of Molecule-Based Magnets Containing Three Spin Carriers, with a Fully Interlocked Structure... 

We know of only two examples of parallel 2D interpenetration involving nets other than (6,3) and (4,4). One is Hittorf s phosphorus, in which two 82-10 nets, composed entirely of phosphorus atoms, interpenetrate [15], The other example, considered in the next section, differs from all the other parallel interpenetrating cases in that the composite formed is a three-dimensional interlocked structure. 

The nonionic template strategy based on hydrogen bonds and to a certain extent on n-n interactions has made catenanes and rotaxanes readily available. The molecular recognition and self-organization process which is responsible for the formation of intertwined and interlocked structures is founded upon the same weak interactions that govern many biological processes. Amide-based catenanes and rotaxanes can thus serve as valuable models for complex molecular recognition patterns in nature. 

However, directionality of individual non-covalent interactions is not always needed and even non-directional forces such as the hydrophobic effect can be utilized for the preparation of interlocked structures. Cyclodextrins may serve as a first example. They are macrocycles built from a-glycosidic D-glucose subunits. While their hydrophilic, OH group-decorated surface makes them water soluble, they bear a lipophilic... 

Beer, P. D., Sambrook, M. R., Curiel, D., Anion-templated assembly of interpenetrated and interlocked structures. Chem. Commun. 2006, 2105-2117. 

S"- Raymo, F. M. and Stoddart, J. F., Polymers with intertwined superstructures and interlocked structures , in Supramolecular Polymers, Ciferri, A. (Ed.), Dekker New York, 2000. 

The functionalisation also allows extending the complexity of intertwined molecular assemblies involving molecular catenanes, rotaxanes and knots. Elaborate interlocked assemblies constructed by means of metal-templation techniques and ji-ji-stacking preorganisation were reviewed [3, 11], Our last survey was devoted to the hydrogen bond templated synthesis of amide-based catenanes and rotaxanes [32], Since then a considerable advancement in elucidation of mechanisms of templation and derivatisation of the amide-based interlocked structures has been reached. Moreover, in 2000 we reported a one pot synthesis of amide-based knots such as 8 [21], which is so far the easiest preparation of molecular knots. In the following, specific possibilities of functionalisation of amide-based catenanes, rotaxanes and knots will be discussed. 

In the introduction we mentioned extravagant interlocked structures of higher complexity such as doubly intertwined catenane and molecular composite knots of Sauvage et al. and multicatenanes made up of 4 to 7 interlocked rings obtained by Stoddart et al. In this section, we will discuss assemblies made up of amide-based catenanes, rotaxanes and knots. Here we use the term assembly to describe covalent or... 

Kim, Kimoon, Self-Assembly of Interlocked Structures with Cucurbituril Metal Ions and Metal Complexes, 5, 371. 

The supermolecules that have been synthesized include large metallocyclic rings, helices, host-guest complexes, and interlocked structures such as catenanes, rotaxanes, and knots. 

Numerous interlocked structures [25], including a [5]catenane (olympiadane) [26], were built using the self-organization of crown ether derivatives containing... 

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