847232-73-9Relevant academic research and scientific papers
Selective access to constitutionally identical, orientationally isomeric calix[6]arene-based [3]rotaxanes by an active template approach
Bazzoni, Margherita,Andreoni, Leonardo,Silvi,Credi, Alberto,Cera, Gianpiero,Secchi, Andrea,Arduini, Arturo
, p. 6419 - 6428 (2021)
Tris(phenylureido)calix[6]arene is endowed with unique properties that make it a valuable macrocyclic component for the synthesis of mechanically interlocked molecules. Its three-dimensional and intrinsically nonsymmetric structure is kinetically selective toward two processes: (i) in apolar media, the threading of bipyridinium based axle-like components takes place exclusively from the upper rim; (ii) SN2 alkylation reactions of a pyridylpyridinium precursor engulfed in the cavity occur selectively at pyridylpyridinium nitrogen atom located at the macrocycle upper rim (active template synthesis). Here we exploit such properties to prepare two series of [3]rotaxanes, each consisting of three sequence isomers that arise from the threading of two identical but nonsymmetric wheels on a symmetric thread differing only for the reciprocal orientation of the macrocycles. The features of the calix[6]arene and the active template synthetic approach, together with a careful selection of the precursors, enabled us to selectively synthesise the [3]rotaxane sequence isomers of each series with fast kinetics and high yields.
Synthesis and Characterization of Constitutionally Isomeric Oriented Calix[6]arene-Based Rotaxanes
Zanichelli, Valeria,Ragazzon, Giulio,Arduini, Arturo,Credi, Alberto,Franchi, Paola,Orlandini, Guido,Venturi, Margherita,Lucarini, Marco,Secchi, Andrea,Silvi, Serena
, p. 1033 - 1042 (2016/03/01)
Oriented rotaxanes composed of tris(N-phenylureido)calix[6]arene wheel 1 and N,N′-dialkyl viologen-based axles were synthesized in which the span between the diphenylacetyl stoppers at the wheel upper and lower rim and the bis-pyridinium cation portion of
Selective synthesis of two constitutionally isomeric oriented calix[6]arene-based rotaxanes
Arduini, Arturo,Ciesa, Flavio,Fragassi, Marcello,Pochini, Andrea,Secchi, Andrea
, p. 278 - 281 (2007/10/03)
Only in apolar media is the calix[6]arene wheel threaded from its upper rim by asymmetric bipyridinium axles. This leads to the formation of oriented pseudorotaxanes. Their stoppering with a different stopper yields rotaxanes characterized by the unequivo
