An Anthracene‐Based Photochromic Macrocycle as a Key Ring Component To Switch a Frequency of Threading Motion

Abstract

A concept and demonstration of a switching in frequencies of molecular motions are described using a pseudorotaxane system. The setup consists of dibenzylammonium hexafluorophosphate and a photochromic dianthrylethane-based [24]crown-8-type macrocycle, which we designed as a key ring component for the pseudorotaxane system having photocontrollable threading functionality by changing the size of ring component due to the action of light.

Synthetic Molecular Machines and Polymer/Monomer Size Switches that Operate Through Dynamic and Non-Dynamic Covalent Changes

“…8e1) than for the rotaxane where it is in its closed form (Fig. 8e2) [88]. This molecular brake function is thermally reversible; -where the ortho-phenylene unit of the macrocycle (Fig.…”

A Shuttling Molecular Machine with Reversible Brake Function

“…A solution of amine 5 (1.42 g, 3.28 mmol), di-tert-butyl dicarbonate (Boc 2 O) (711 mg, 3.26 mmol), and N, N-dimethylaminopyridine (DMAP) (18 mg, 16 mmol) in CH 2 Cl 2 (25 mL) was stirred at room temperature for 2 h. After evaporation of the solvent, chromatography on silica gel (eluent: hexane/ethyl acetate) gave 11 (818 mg, 47 %) as a pale yellow oil. 1 9,166.8,155.8,145.6,139.2,136.4,129.8,129.7,129.1,128.8,128.3,128.1,127.9,127.6,127.1,80.4,52.9,52.8,52.1,52.0,49.5,28.5 ppm;IR (neat): ñ = 3334 (br), 2977, 2952, 2842, 1723, 1694, 1612, 1456, 1435, 1408, 1366, 1281, 1164, 1111, [a] nd [a] < 86 [d,c]…”

“…[8] Very recently, we reported a substantial change of the slippage/deslippage rates of a pseudorotaxane system caused by light and heat. [9] On the basis of these results, we designed a rotaxane system that has a reversible brake function for shuttling motion by utilizing a size-changeable crown ether as the ring component. Here we report the synthesis of the [2]rotaxane and quantitative evaluation of the change of its shuttling rates by 1 H NMR measurement.…”

“…Thus, construction of a braking system at a molecular scale capable of reversible switching of rates by physical stimuli has not been achieved 8. Very recently, we reported a substantial change of the slippage/deslippage rates of a pseudorotaxane system caused by light and heat 9. On the basis of these results, we designed a rotaxane system that has a reversible brake function for shuttling motion by utilizing a size‐changeable crown ether as the ring component.…”

Oligomerization of 3,5-Dimethyl Benzyl Alcohol Promoted by Clay: Experimental and Theoretical Study

“…In this context, we considered the possibility of carrying out the oligomerizacion of benzyl alcohols in the presence of montmorillonite (Tonsil Optimum Extra) [ 4 ] to obtain fused aromatic hydrocarbons. These compounds, whose structures have photo and electrochemical [ 5 ] properties employed in optical devices [ 6 ], polymeric materials [ 7 ], and potential therapeutics [ 8 ] are commonly known as acenes [ 9 ]. Anthracene and its derivatives are some of the most important types of polycyclic aromatic compounds prepared by means of a Friedel-Crafts reaction [ 10 ], aromatic cyclodehydration [ 11 ], Lewis acid-induced Bradsher-type reaction from diarylmethanes [ 12 ], acid-promoted transannular cyclodehydration [ 13 ] and homologation mediated by metallacycles [ 14 , 15 ].…”