[2]Rotaxane End‐Capping Synthesis by Click Michael‐Type Addition to the Vinyl Sulfonyl Group

Abstract

We report the application of the click Michael-type additionr eactiont ov inyl sulfone or vinyl sulfonate groups in the synthesis of rotaxanes through the threading-and-capping method. This methodology has proven to be efficient and versatile as it allowed the preparation of rotaxanes using template approaches based on different noncovalent interactions (i.e.,d onor-acceptor p-p interactions or hydrogen bonding) in yieldso fg enerally 60-80 %a nd up to 91 % aided by the mild conditions required (room temperature or 0 8Ca nd am ild base such as Et 3 No r4 -(N,N-dimethylamino)pyridine (DMAP)). Furthermore, the use of vinyl sulfonate moieties, whicha re suitable motifs for coupling-and-decoupling (CAD) chemistry,i mpliesa nother advantage because it allowst he controlled chemical disassembly of the rotaxanes into their components through nucleophilic substitution of the sulfonatesr esultingf rom the capping step with at hiol underm ildconditions (Cs 2 CO 3 and room temperature).

Heptagon-Containing Saddle-Shaped Nanographenes: Self-Association and Complexation Studies with Polycyclic Aromatic Hydrocarbons and Fullerenes

“…Once inquired into the self-association process of saddle-shaped hept-HBCs 1-5, further investigations on their complexation with a selection of guests of different geometry and electronic nature were accomplished. Among the flat guests, we proposed pyrene and benzo[a]pyrene as planar nonfunctionalized PAHs, naphthalene diimide (NDI) 8 as a π-acceptor, 55 1,5-dialkoxynaphthalene 9 as a π-donor, and corannulene, C 60 , and C 70 as curved guests (Figure 3). The association constants (K a ) between NGs and PAHs or fullerenes were determined by 1 H or 13 C NMR titrations in CDCl 3 or o-DCB-d 4 at r.t.…”

“…Anhydrous THF was freshly distilled over Na/benzophenone. Pd(PPh 3 ) 4 , 59 and compounds 1, 49 4, 47 7, 51 and 8 55 were prepared according to literature procedures.…”

Vinyl sulfonyl chemistry-driven unidirectional transport of a macrocycle through a [2]rotaxane

“…S1 and S2). Subsequently we performed a DMAPcatalyzed MAVS reaction 23,28 of thiol stopper 11 (see ESI for the synthesis) to the terminal vinyl sulfone group in 10•PF 6at 0 °C, yielding the target [2]rotaxane 13•PF 6in 66% yield (Scheme 3a).…”

“…25 Thus, we demonstrated the utility of this CAD chemistry both to build a rotaxane and to subsequently chemically cleave it in a controlled manner to disassemble it into its components, thus, allowing the development of a cleavable rotaxane. 23 Therefore, we envisaged that the chemistry of vinyl sulfone and vinyl sulfonate groups could be an efficient tool for the Please do not adjust margins…”

Aqueous assembly of a (pseudo)rotaxane with a donor–π–acceptor axis formed by a Knoevenagel condensation

“…Depending on the particular implementation, fluorescence enhancement, electron and/or energy transfer mechanisms can be incorporated in optical triggered molecular switches, typically as a function of the proximity of the components involved. [1][2][3][4] Commonly employed dyes include rylene diimides, [5][6][7] naphthalene imides, 8 azo dyes, [9][10][11] squaraines, 12,13 and poly-aromatic hydrocarbons like anthracene 14,15 or pyrene. 16 Despite the growing library of rotaxanes, only very few examples comprising linear donor-πacceptor "push-pull" chromophores are reported.…”