The synthesis and characterisation of calix[6]arene-based lasso-like molecular structures is described. These interwoven structures consist of an electrochemical responsive N,N’-dialkylviologen arm covalently anchored at the upper rim of a triphenylureido calix[6]arene-based wheel. Upon reduction of the viologen core, a hollow tridimensional macrocyclic structure can be generated. This process is reversible, and the original lasso-like structure can be regenerated by oxidizing the viologen arm to its original dicationic form. Electrochemical and EPR techniques investigated the ability of the system to perform threading/ dethreading movements upon redox switching. The functionalisation of the arm ω-hydroxy ending with a bulky diphenylacetyl group converts the self-threaded structure in a blocked interwoven molecular com- pound belonging to the class of [1]rotaxanes. The ability to form dimeric structures in the shape of a [c2] daisy chain was also demonstrated, an unprecedented result for calixarene macrocycles
Synthesis and properties of a redox-switchable calix[6]arene-based molecular lasso / Orlandini, Guido; Casimiro, Lorenzo; Bazzoni, Margherita; Cogliati, Beatrice; Credi, Alberto; Lucarini, Marco; Silvi, Serena; Arduini, Arturo; Secchi, Andrea. - In: ORGANIC CHEMISTRY FRONTIERS. - ISSN 2052-4129. - 7:(2020), pp. 648-659. [10.1039/C9QO01379B]
Synthesis and properties of a redox-switchable calix[6]arene-based molecular lasso
Bazzoni, Margherita;Cogliati, Beatrice;Arduini, Arturo
;Secchi, Andrea
2020-01-01
Abstract
The synthesis and characterisation of calix[6]arene-based lasso-like molecular structures is described. These interwoven structures consist of an electrochemical responsive N,N’-dialkylviologen arm covalently anchored at the upper rim of a triphenylureido calix[6]arene-based wheel. Upon reduction of the viologen core, a hollow tridimensional macrocyclic structure can be generated. This process is reversible, and the original lasso-like structure can be regenerated by oxidizing the viologen arm to its original dicationic form. Electrochemical and EPR techniques investigated the ability of the system to perform threading/ dethreading movements upon redox switching. The functionalisation of the arm ω-hydroxy ending with a bulky diphenylacetyl group converts the self-threaded structure in a blocked interwoven molecular com- pound belonging to the class of [1]rotaxanes. The ability to form dimeric structures in the shape of a [c2] daisy chain was also demonstrated, an unprecedented result for calixarene macrocyclesI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.