Macrocyclic Hamilton receptor-shuttling dynamics in [2]rotaxanes

Abstract

Electronic Supplementary Information (ESI) available: experimental procedures, characterization data of 1, 2, and 4 (1 H, 13 C, VT NMR) and molecular modeling structures of rotaxanes 1, 7, 8 and 9. Macrocyclic Hamilton receptor-shuttling dynamics in [2]rotaxanes Inherent movement of a macrocycle comprising a multi-site hydrogen bonding Hamilton-type receptor in a series of [2]rotaxanes was investigated by dynamic and VT NMR. In these rotaxanes the varying nature and number of hydrogenbond motifs and stations on the molecular axles influenced ring dynamics. Triazole stations interact selectively by hydrogen bonding with the isophthalamide amide bonds present in the Hamilton macrocycle and fast shuttling (72 kHz at 25 °C) was observed in a two station variant.

Hydrogen‐Bonded Supramolecular Polymer Adhesives: Straightforward Synthesis and Strong Substrate Interaction

“…Aiming at fabricating the side-chain Ba-and HW-functionalized P(nBuA-co-Ba-co-HW) polymer (Figure 1), we have first prepared a random copolymer P(nBuA-co-TIaAm) (Mn NMR = 27.3 kg/mol, Mn SEC = 30.6 kg/mol, Ð = 1.25), using 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (DDMAT) as chain transfer agent and RAFT polymerization. 23,[25][26][27] The theoretical number-average molar mass (Mn th = 25.5 kg/mol), evaluated from the monomers' conversion, is consistent with the experimental ones (Mn NMR and Mn SEC) and proves the controlled character of such RAFT copolymerization. The introduction of TIaAm monomer together with n-butyl acrylate (nBuA) allows to precisely tune the glass-transition as well as the hydrophilic/hydrophobic balance of the resulting H-bonding polymer.…”

“…Compared to the existing H-bonded supramolecular polymeric adhesives, a novel synthetic design and strategies thereto are continually sharpened. The association of heterocomplementary barbiturate (Ba) and Hamilton wedge (HW) into sextuple hetero-complementary H-bonding arrays has been studied by us [18][19][20][21][22] and others, [23][24][25] to reversibly bond together separated blocks, allowing the construction of supramolecular polymeric architectures, well-defined nanostructures, and selfhealing materials. Although H-bonding interactions have been demonstrated to improve interfacial adhesion, the Ba/HW couple remains surprisingly unexplored in its bonding capability onto various substrates and in macroscopic adhesive applications.…”

Hydrogen‐Bonded Supramolecular Polymer Adhesives: Straightforward Synthesis and Strong Substrate Interaction

“…Aiming at fabricating the side‐chain Ba‐ and HW‐functionalized P( n BuA‐ co ‐Ba‐ co ‐HW) polymer (Figure 1), we have first prepared a random copolymer P( n BuA‐ co ‐TIaAm) ( M n NMR =27.3 kg mol −1 , M n SEC =30.6 kg mol −1 , Ð =1.25), using 2‐(dodecylthiocarbonothioylthio)‐2‐methylpropionic acid (DDMAT) as chain transfer agent and RAFT polymerization [23, 25–27] . The theoretical number‐average molar mass ( M n th =25.5 kg mol −1 ), evaluated from the monomers’ conversion, is close to the experimental ones ( M n NMR and M n SEC ) and in agreement with a controlled character of such RAFT copolymerization.…”

“…Compared to the existing H-bonded supramolecular polymeric adhesives, novel synthetic design and strategies thereto are continually sharpened. The association of hetero-complementary barbiturate (Ba) and Hamilton wedge (HW) into sextuple hetero-complementary H-bonding arrays has been studied by us [18][19][20][21][22] and others, [23][24][25] to reversibly bond separated blocks, allowing the construction of supramolecular polymeric architectures, well-defined nanostructures, and self-healing materials. Although Hbonding interactions have been demonstrated to improve interfacial adhesion, the Ba/HW couple remains surprisingly unexplored in its bonding capability onto various substrates and in macroscopic adhesive applications.…”

Control on dissipative kinetics reveals the entropically-dominated essence of interlocked molecular machines

“…[48,49] We reasoned that by stabilizing the studied pseudorotaxanes thermodynamically we could modulate the dethreading kinetics, slowing it down to a desirable rate, leveraging solvent composition to modulate the performance of molecular machines. [50][51][52][53] Therefore we decided to operate in the mixed solvent system CDCl3:CD3CN 3:1, because CDCl3 is a less competitive solvent for hydrogen bonding interactions with respect to CD3CN. An experimental confirmation of this feature was the increase of the association constant for pseudorotaxane [1bH + ⊂DB24C8], from 225 M -1 to 1800 M -1 .…”