Borromean link

J. Fraser Stoddart the first discrete Borromean-linked molecule, a landmark in topological synthesis. 

The preparation of the Borromean link, in particular, represents a remarkable synthetic accomplishment. This topological tour de force was created in one pot from zinc acetate and the two simple subcomponents shown at right in Figure 1.1, one of which is commercially available ... 

Figure 1.1 Borromean link [22] prepared by Stoddart et al. from zinc(ll) and the dialdehyde and diamine subcomponents shown at right via the simultaneous, reversible formation of covalent (C=N) and coordinative (N—>Zn) bonds. Two of the six corners of the link (at left) have been replaced with straight lines for clarity.

Figure 27(c)]. It remains to be noted that Borromean links composed of metric circles are impossible,108 that Borromean links composed of three triangles or three squares have inspired sculptures by John Robinson,109 and that this link, in the form of three interlocked triangles, was known to the ancient Scandinavians as Odin s triangle or the Walknot (meaning knot of the slain ).110... 

Like knots, links may be prime or composite. The Hopf and Borromean links are examples of prime links because they cannot be divided (factored) into smaller, nontrivial links. Figure 30(a) is the minimal diagram of a composite link that is the abstract representative of some [3]catenanes, one of which is depicted in Figure 30(b).103b That the three-component link is a composite link is shown by the fact that a plane perpendicular to the plane of projection (dashed line) and pierced in exactly two points cuts the link in half If the open ends on both sides of the plane are now joined to form closed curves, two Hopf links result. In analogy to composite knots, the three-component link in Figure 30(a) is denoted by 2 2j, and the five-component composite link that represents olympiadane by 2 2 2 2. ... 

While orientation normally imparts topological chirality, as in the case of the Hopf link, this is not always the case. For example, the Borromean link remains amphicheiral even after orientation.115- 119 This is easily demonstrated with reference to the 5), presentation of the nonoriented link [Figure 27(b)] No matter in which direction the three rings are oriented, the resulting diagram remains centrosymmetric and therefore rigidly achiral. 

Catenanes, rotaxanes, molecular necklace, knots, and Borromean link. 

Fig. 3.25 a Top and side view of the hexagonal nets, b One Borromean weave, c Topological view of the sevenfold interpenetrated 2D —> 3D Borromean-linked structure, one Borromean weave is in thick stick and other six in thin stick [83]... 

Carlucci L, Ciani G, Proserpio DM (2003) Borromean links and othra- non-conventional links in polycatenated coordination polymers re-examirration of some puzzling networks. CrystEngComm 5 269... 

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