Covalent fixed multicyclic polystyrene conformers

Abstract

Covalent fixed multicyclic polystyrene conformers were synthesized from inconvertible polystyrene conformers based on p-tert-butylthiacalix[4]arene by azidation and subsequent click coupling. Selective 1D NOESY analyses confirmed that the spatial structures of star polystyrene precursors and multicyclic polystyrenes were preserved during the azidation and click coupling processes. The conformation of star polymers affected degree of decrease in the hydrodynamic volume after cyclization but had little effect on glass transition behavior. The rigid core of star polymer increased the T g but in the case of multicyclic polymer, this influence of core structure was reduced. V C 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 4020-4026

Synergy of Macrocycles and Macromolecular Topologies: An Efficient [34]Triazolophane-Based Synthesis of Cage-Shaped Polymers

“…Furthermore, the topological conversion via cross-metathesis (CM) of H -shaped and eight -shaped polymers to their three- and four-arm cage -shaped polymers were subsequently reported by the same author. Similar bimolecular approaches with no electrostatic preorganization were later reported by Paik and colleagues, who combined the atom-transfer radical polymerization (ATRP) and the copper­(I)-catalyzed azide–alkyne cycloaddition (CuAAC) click chemistry to form three- and four-arm − cage -shaped polymers. Beside these first intermolecular reports, an elegant alternative arose from the olefin metathesis field research and was proposed by Satoh and co-workers .…”

“…Remarkably, in the case of P1 cage , the M n,SEC was shifted to higher values (+12.3%) compared to P1 end‑func , which is indicative for a larger hydrodynamic volume and corroborates the formation of a more rigid macromolecular structure of the cage compared to a simple linear oligomerization of the polymer arms. To the best of our knowledge, this represents the first finding of this kind of topological transition. − Noteworthy, this initial effect was progressively compensated with increasing chain length of the star arms and overcome by the commonly observed hydrodynamic volume shrinking effect of cages, as shown by the respective M n,SEC precursor value shifts of P2 cage (−1.8%), P3 cage (−12.9%), and P4 cage (−20.3%; Figure a).…”

“…Relatively to the initial star -shaped polymers, the incorporation of large aromatic end-groups in their structure seemingly interfered with a proper packing of the ε-CL units, resulting in a significantly larger D h . However, once the cage -shaped polymers were formed, the hydrodynamic diameter of the cage remained larger than that of the initial star polymer structures, upholding the lack of a real hydrodynamic shrinking effect as it is known for polymer cages. − …”

Cage‐Shaped Polymers Synthesis: A Comprehensive State‐of‐the‐Art

“…A few years earlier, the syntheses of three- [10,11] (Table 2, Entries 5 and 6 and Scheme 3,II) and four-arm [12][13][14] (Table 2, Entries 7-9 and Scheme 3,III) polystyrene (PS) cages through a combination of atom transfer radical polymerization (ATRP) and copper(I)catalyzed alkyne-azide cycloaddition (CuAAC) were reported by Paik and coworkers. All topological conversions were designed to occur via intermolecular coupling between azide end functionalized star-shaped polymer precursors and tri-or tetra-functional alkyne linkers.…”

Topologically Reversible Transformation of Tricyclic Polymer into Polyring Using Disulfide/Thiol Redox Chemistry

“…Various topologically appealing multicyclic polymers including sun-shaped, , tadpole-shaped, − 8-shaped, , manacle-shaped, paddle-shaped polymers, and spiro form multicyclic polymer are also prepared through controlled radical polymerization or anionic polymerization. Our group has also reported multicyclic polymers, like theta-shaped bicyclic, − 8-shaped polymers, and cage-shaped tricyclic polymers, ,, by combining atom transfer radical polymerization (ATRP) and click reactions.…”