Oligocatenanes Made to Order¹

Abstract

The construction of catenanes, comprised of between two and seven interlocked rings, has been achieved. Two tris-1,5-naphtho-57-crown-15 macrocycles template the formation of cyclobis(paraquat-4,4′biphenylene) to give a [3]catenane, which acts as a template for the construction of one and then another cyclobis(paraquat-p-phenylene) to give a [4]-and [5]catenane (Olympiadane). When high pressure was used in these templated syntheses, a [6]-and [7]catenane, as well as a [5]catenane that is topologically isomeric with Olympiadane, were also obtained. X-ray analyses of the [3]-, [5]-, and [7]catenanes reveal an optimum use of electrostatic, π-π stacking, [C-H‚‚‚π] interactions, and [C-H‚‚‚O] hydrogen bonds in the organization of the component rings within the molecules. Noteworthy in the [7]catenane structure is the location of four of the PF 6anions within voids present in the 20 + ion. Temperature-dependent 1 H NMR spectroscopic studies and electrochemical investigations have revealed the dynamic and redox behavior of these catenanes in solution.

The Cucurbit[n]uril Family

“…[181][182][183][184] The members of the [n]MN family are topological isomers of the linear oligocatenanes exemplified by olympiadane (Figure 8). [185] The interaction of 45 with CB [6] results in pseudorotaxane CB [6]·45. During this process the butanediammonium linker is rigidified in its all trans conformation, with the pyridyl groups displayed in roughly opposite directions.…”

Chemical synthesis gets a fillip from molecular recognition and self-assembly processes

“…It was very much in this spirit that the synthetic goals summarized in Fig. 5 were reached (28). Both the (5)catenane 13⅐12PF 6 , also known as olympiadane, and the doubly branched (7)catenane 15⅐20PF 6 provided good quality single crystals from which x-rays have shed a unique light on the exquisite order present in these molecules.…”

Template-Directed Synthesis of a Rotacatenane

“…[3] The two macrocyclic components are held together by a mechanical bond reinforced by (i) [CϪH···O] hydrogen bonds between the α-bipyridinium hydrogen atoms and the polyether oxygen atoms, (ii) [π···π] stacking between the π-electron-rich and -deficient units, and (iii) [CϪH···π] interactions between the hydrogen atoms of the 1,5-dioxynaphthalene unit located inside the cavity of the tetracationic cyclophane and the p-phenylene rings. The cavities of the mechanically interlocked macrocycles of 1 · 4 PF 6 are large enough to accommodate ( Figure 1) π-electron-rich and -deficient aromatic substrates, as revealed [1] by preliminary complexation studies. Inspired by these observations, we identified ( Figure 1) a mechanically interlocked receptor for π-electron-rich aromatic substrates in the shape of the [2]catenane 2 · 4 PF 6 .…”

“…However, we cannot establish if these energy barriers are associated with degenerate or non-degenerate ried out on these two compounds led to the determination of the free energy barriers associated with a number of coprocesses or with a combination of both. [8] The compounds 1/5DN38C10, [9] 1 · 4 PF 6 , [1] s [10] 4, [10] and 6 [11] were prepared as described previously 7.10Ϫ6. .…”

“…post-assembly covalent modification of the corresponding The [2]catenane 1 · 4 PF 6 ( Figure 1) was obtained [1] as a supramolecular complex into a rotacatenane 7 · 4 PF 6 , (iii) side product in the two-step template-directed synthesis of the X-ray crystallographic analysis of the [2]catenanes oligocatenanes incorporating from four up to seven mech-1 · 4 PF 6 and 2 · 4 PF 6 , and (iv) the variable-temperature anically interlocked [2] macrocycles. This [2]catenane is com-1 H-NMR-spectroscopic investigation of the dynamic proposed of a 1,5-dioxynaphthalene-based macrocyclic poly-cesses associated with both the [2]catenane 2 · 4 PF 6 and ether and of a bipyridinium-based tetracationic cyclo-with the rotacatenane 7 · 4 PF 6 in solution.…”