Bis(meta-phenylene)-32-crown-10-based cryptand/diquat inclusion [2]complexes

Abstract

Bis(meta-phenylene)-32-crown-10-based cryptands have been proved to complex diquat much more strongly than bis(meta-phenylene)-32-crown-10 itself; in fact, one containing a pyridyl moiety has one of the highest Ka values yet reported.

Supramolecular Species Bearing Quaternary Azaaromatic Moieties

“…72 Threading of α-CD onto dipyridinium dichloride (36a) and its symmetrically substituted derivatives (36b,c) and (37a-c) as well as unsymmetrically substituted derivatives (38) and (39) shuttling processes. 74 The rotaxane (42) In rotaxane (43) upon heating, the α-CD molecule shuttles within the azobenzene unit below 100 o C, and between two stoppers at temperatures above 100 o C.…”

“…Since the number of supramolecular species bearing quaternary azaaromatic moieties is very large, [22][23][24][25][26][27][28][29][30] inclusion complexes with host molecules such as crown ethers, 31 cyclodextrins, 32-36 cucurbiturils 37,38 and calixarenes, 39,40 as well as examples of molecular elevators, 41 taco complexes 42 and cryptand-based pseudorotaxanes [43][44][45] are not described here. The references are cited starting from 2005.…”

A Shuttle for the Transport of Protons Based on a [2]Rotaxane

“…Thus the protonation/deprotonation process is coupled with movement of the protons along the axis as needed for a proton pump. Movement of a macrocycle upon protonation has been observed with related pseudorotaxanes,23,24 but of course, these pseudorotaxanes disassemble upon protonation. In this work, we present the synthesis of a rotaxane that contains the mobile protonatable site in the ring.…”

A chromophoric switch based on pseudorotaxanes

“…1͑a͒ Appealing examples of chemical compounds where controlled mechanical movements can take place are suitably designed pseudorotaxanes, rotaxanes, and catenanes. 8 Recently, Huang et al 9 showed a cryptand/paraquat ͓2͔pseudorotaxane which can be reversibly switched off ͑and back on͒ by protonation ͑and depro-tonation͒ of the host, and Mendoza et al reported the experimental and theoretical studies of the adsorption of fumaramide ͓2͔rotaxane on Au and Ag surfaces. 8 Recently, Huang et al 9 showed a cryptand/paraquat ͓2͔pseudorotaxane which can be reversibly switched off ͑and back on͒ by protonation ͑and depro-tonation͒ of the host, and Mendoza et al reported the experimental and theoretical studies of the adsorption of fumaramide ͓2͔rotaxane on Au and Ag surfaces.…”