Threaded complex

Figure 2.22. The equilibria shown here involve a mixture of macrocyclic chelate (E), open chelate (A), and metal cation (black disk), on the one hand, and different complexed species, on the other hand The threaded complex (F) or a mixture of homoleptic complex (B), metal-complexed macrocycle (G), and free-macrocycle (E).

Figure 2.25. Copper(I)-templated threading of macrocycle 58 onto 1,10-phenanthroline-based molecular threads containing two such chelates 59, 60, 61, and 62, to afford threaded complexes 63, 64, 65, and 66 respectively.

Figure 2.26. Assembly, by Cu(I)-templated threading, of two zinc porphyrins appended to a chelating macrocycle (67). Bis-chelate molecular threads 68, 69, and 70 provide threaded complexes 71, 72, and 73 respectively.

The precatenate intermediate can be regarded as a threaded complex, which is thermodynamically stabilized by coordination bonds, from this simple consideration, a transition metal-templated synthesis of rotaxanes was devised, the principle of which is shown in Figure 28 [117]. The threading step (i) is a complexation reaction. 

Fig. 2 The Cu(I)-directed threading reaction A is a macrocyclic compound incorporating a dpp fragment (indicated with a thick line), B is a dpp-containing molecular thread and the black disk is Cu . C is the threaded complex formed...

The approach used for construction of porphyrin stoppered-rotaxanes is based on the template synthesis described in Fig. 2. On the threaded complex (C), porphyrins playing the role of big stoppers can be constructed, to prevent dethreading of the dumbbell from the ring after removal of the template metal. In Fig. 3 two possible rotaxanes are indicated that can be formed (a [2]- or a [3]rotaxane) by following this construction principle. This figure also shows that this strategy permits us to introduce two different metalated porphyrins in a stepwise manner. 

Scheme 6.3 Equilibria Fot ion-pair dissociation horizontal processes) and host-guest association vertical processes) of the investigated system. Re nesentation of the species in G-I as a threaded complex is hypothetical (see the text for more details)...

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