Rotaxan‐Verbindungen, I¹⁾

Abstract

Rofaxane Compoimnds, IThe name rotaxanes is suggested for newly synthesized aggregates of the type 1 consisting of a macrocycle and a chain with bulky end groups. As a model compound 4-(11-hydroxyundecy1)-catechol (11) can be ketalized with 1,21-dichlorheneicosan-l I-one to the benzodioxole 12. From the catechol-diol 16 the diansa compound 25b is synthesized which is then converted to the prerotaxane t6b with N-acety1-2,4,6-tri-p-tolylaniline, the structure of which is confirmed by the mass spectrum. T h e cleavage of the ketal 26b with hydrobromic acid affords the prerotaxane 27 coupled via N only, which after dehydrogenation and hydrolysis gives the rotaxane 29. Reductive acetylation leads to the hexaacetate 30. The corresponding non-rotaxane-like components, the pentaacetate 54 and the 1 -acetyl-I -aza-cyclohexacosan-14-one, are clearly different on thin layer chromatography from the rotaxane 30 which appears as a single spot with several mobile phases. The identical i.r.-spectrum of the rotaxane compounds 30 and of an equimolar mixture of the components (Fig. I ) confirms the postulated structure.

Mechanically bonded macromolecules

“…Fig. 2 shows the graphical representations of some of these mechanically interlocked macromolecules-namely, (a) main-chain [n]catenanes, (b) bridged poly [2]catenanes, (c) pendant poly [2]catenanes, (d) side-chain poly [2]catenanes, (e) main-chain [n]rotaxanes, (f) linear poly[c2]daisy chains, as well as (g) mechanically interlocked dendrimers. Various approaches and synthetic strategies have been employed in synthesising these constitutionally and topologically diverse targets.…”

“…Using this approach (Strategy II), we have achieved 27 (Scheme 2) the synthesis of two main-chain poly(bis [2]catenane)s 4Á8nPF 6 and 5Á8nPF 6 , a main-chain poly([2]catenane) 6Á4nPF 6 , and a pendant poly [2]catenane 7Á4nPF 6 with degrees of polymerisation up to as far as 25.…”

“…In order to construct a pendant polycatenane, a [2]catenane incorporating two reactive functional groups on one of its two macrocyclic components had to be used. In one example, two hydroxymethyl groups were installed on the macrocyclic polyether component of the monomeric [2]catenane, while the CBPQT 4+ component remained unfunctionalised. Reaction of this [2]catenane with bis(4-isocyanatophenyl)methane yielded the pendant poly[2]-catenane 7Á4nPF 6 .…”

“…In one example, two hydroxymethyl groups were installed on the macrocyclic polyether component of the monomeric [2]catenane, while the CBPQT 4+ component remained unfunctionalised. Reaction of this [2]catenane with bis(4-isocyanatophenyl)methane yielded the pendant poly[2]-catenane 7Á4nPF 6 . Chloride salts of all these polycatenanes (4Á8nCl-7Á4nCl) were analysed in aqueous solution by gel permeation chromatography (GPC).…”

“…Presently a fourth year graduate student, after spending his first three years in UCLA, Mark is now finishing up his PhD in organic chemistry under the tutelage of Professor Stoddart at Northwestern University. His focus is on the synthesis of exotic molecular switchable materials including bistable side-chain poly [2]catenanes, reconfigurable (Au, Pt, Pd, Ag) nanoparticle assemblies, and reprogrammable self-assembling polymer blends.…”