Catenanes doubly interlocked

Singly and doubly interlocked [2]catenanes can exist as topological stereoisomers (see p. 144 for a discussion of diastereomers). Catenanes 35 and 36 are such stereoisomers and would be expected to have identical mass spectra. Analysis showed that 35 is more constrained and cannot readily accommodate an excess of energy during the mass spectrometry ionization process and, hence, breaks more easily. 

Figure 10.54 Topological isomerism, diastereoisomerism and chirality as related to a [2] catenane, a trefoil knot and a doubly interlocked [2] catenane.

Figure 10.89 Conceptual production of increasingly interlocked species through the use of multime-tallic helicates. (a) Doubly interlocked [2]catenane from three metal centres, (b) Pentafoil knot from four metal ions, (c) Triply interlocked [2]catenane. (Reproduced with permission from [98]).

Dietrich-Buchecker, C., Leize, E., Nierengarten, J. F., Sauvage, J. P, Vandorsselaer, A., Singly and doubly interlocked [2]-catenanes - influence of the degree of entanglement on chemical-stability as estimated by fast-atom-bombardment (Fab) and electrospray-ionization (Esi) mass spectrometries (Ms). J. Chem. Soc., Chem. Commun. 1994, 2257-2258. 

The synthesis of the first doubly interlocked [2]-catenane, based on the three-dimensional template effect of Cu+I, has been completed in principle, helices containing an odd number of metal centers lead to even numbered crossing [2]-catenanes [94JA375]. 

Fig. 29 Solid-state structure of the doubly interlocked [2] catenane (Solomon Knot) that emerges unexpectedly from a DCL containing DAB, DFP, and a 1 1 mixture of Zn2+ and Cu2+templates [217]...

This strategy has been further extended to the synthesis of a triply twisted tris[bis(phenanthroline)copper(I)] complex analogous to (35) which, after correct linking of the termini and demetalation, leads to a doubly interlocked catenane structure [46]. 

Figure 33 Strategy for the synthesis of a doubly interlocked catenane. Reproduced with permission from reference 96.

Ibukuro. F. Fujita, M. Yamaguchi, K. Sauvage, J.-P. Quantitative and spontaneous formation of a doubly interlocking [2]catenane using copper(I) arid palladium(II) as templating and assembling centers. J. Am. Chem. Soc. 1999, 121. 11014-1 1015. 

Fig. 4 Lithium-ion-templated formation of a doubly interlocked [2]catenane. (From Ref [13])...

IJ-catenane "pretzel" "hook-and-ladder" L2J-catenanes Surface Bound Doubly Interlocked... 

The intent of metal coordination is to provide both a robust tanplate platform and a large diversity of stereochonical geometries defined by the coordination properties of the metal. In addition to tetrahedral and octahedral coordination geometries obtained, for example, with Cu(I) or Zn(II), respectively, linear arrangements can be obtained using Au(I) centers coordinated to alkyne- and phosphine-terminated strands to prepare different types of catenates. 2 Square planar coordination around Pd(II) was also used to generate a doubly interlocked [2]catenane, known as a Solomon link. ... 

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... 

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