Effect of metallosupramolecular polymer concentration on the synthesis of poly[n]catenanes

Abstract

Concentration of the metallosupramolecular polymer precursors have a significant effect on the architecture and size of the resulting poly[n]catenanes formed via a ring closing metathesis step.

Metastable doubly threaded [3]rotaxanes with a large macrocycle

“…2 equiv., see ESI, Fig. S2 †) and the mixture was equilibrated for 1 day at 45 C. Aer equilibration, the 1 H-NMR spectrum simplied and, using previously published 1 H NMR spectra of doubly threaded metal-templated Bip complexes, [87][88][89] it is possible to assign each resonance peak to a given proton in the complex (Fig. 1 and 2b).…”

“…The presence of such upeld shied peaks imply these protons are in a more shielded environment, and would be consistent with an interlocked structure. [87][88][89] A MALDI-TOF MS spectrum (see ESI, Fig. S12 †) of the reaction mixture recorded aer 6 minutes in solution conrmed only the presence of 1 and 6, with no signals indicative of [3]rotaxane 7.…”

“…While a wide range of ligands have been explored to access mechanically interlocked structures, 72 the terdentate ligand, 2,6-bis(N-alkyl-benzimidazolyl)pyridine (Bip), has a number of attractive features including a exible and scalable synthesis combined with the ability to tailor its solubility by altering its N-alkyl moieties. 80 It has also been used to access metallosupramolecular assemblies and polymers, [81][82][83][84][85] [2]catenates, 86 [3]catenates, 87 and poly[n]catenanes 88,89 via metal ion coordination. As such, this study utilizes Bip/metal ion templating to access isolatable doubly threaded [3]rotaxanes (Fig.…”

Polycatenanes: synthesis, characterization, and physical understanding

“…Data suggested that the MSP was present in both the linear and cyclic form, the ratio of which depends on the reaction concentration. 72 Ring closing the thread component in the MSP was achieved through olefin metathesis of its alkene tails resulting in a mixture that contains the metalated poly[ n ]catenanes. Removal of the metal ion yielded the desired poly[ n ]catenane 30 , along with some non-interlocked species.…”

“…In these high concentration reactions, evidence from MALS suggests the presence of poly[n]catenanes with up 640 interlocked rings (1000 kg mol À1 ). 72 As a consequence of the metal ion templating employed in the synthesis of the poly[n]catenanes, 30 exhibits stimuli-responsive behaviour. When the ligand moieties in these catenanes are not complexed to metal ions, the rings are mobile; however, adding in the metal ions results in the reformation of the metal-ligand complexes and a locking in of the catenane units.…”