Knots directed synthesis

Figure 24. The template-directed synthesis of the trefoil knot 69-6PF6 and of its isomeric trivial knot 70-6PF6-...

Ashton, P. R., Matthews, 0. A., Menzer, S., et ai, Molecular meccano, 27 - A template-directed synthesis of a molecular trefoil knot. Liebigs Annalen-Recueil 1997, 2485-2494. 

Raymo, F.M., Stoddart, J.F. Organic Template Directed Synthesis of Catenanes, Rotaxanes and Knots. In ref. 4b, p.143. 

Metal-directed Synthesis -Rotaxanes, CatenaneSy Helicates and Knots... 

Two-directional synthesis can be used in a folding pathway approach, so that a symmetrical substrate can be used as a molecular rope that is tied into knots to get efficient formation of a range of linear and polycyclic architectures with NP-Hke features. This nice piece of work was reported by Stockman et al. [22], who used diethyl-7-oxotrideca-2,ll-dienedioate 134 as the common substrate to yield 12 scaffolds (Scheme 13.20). Although simple reactions such as the Grignard reaction yielding the corresponding tertiary alcohol 135 did not... 

The use of metal coordination in the template-directed synthesis of knots and links is one of the earliest successful strategies employed by chemists. The first example of metal-templated synthesis of a [2]catenane was reported in Strasbourg by Sauvage et al. who first used the method to assemble two phenanthroline-based strands around a tetrahedral copper(I) cation (Scheme 17.1). 

In order to illustrate this approach, we next consider the optimization of an ammonia synthesis reactor. Formulation of the reactor optimization problem includes the discretized modeling equations for a packed bed reactor, along with the set of knot placement constraints. The following case study illustrates how a differential-algebraic problem can be optimized efficiently using (27). In addition, suitable accuracy of the ODE model can be obtained at the optimum by directly enforcing error restrictions and adaptively adding elements. Finally, bounds on the continuous state profiles can be enforced directly in the optimization problem. 

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