Remote Control of the Synthesis of a [2]Rotaxane and its Shuttling via Metal‐Ion Translocation

Abstract

This paper is dedicated to Prof. Jean-Marie Lehn on the occasion of his 80th birthday with deep gratitude for his inspiring and groundbreaking work.Remote control in an eight-component network commanded both the synthesis and shuttling of a [2]rotaxane via metal-ion translocation, the latter being easily monitored by distinct colorimetric and fluorimetric signals. Addition of zinc(II) ions to the red colored copper-ion relay station rapidly liberated copper(I) ions and afforded the corresponding zinc complex that was visualized by a bright sky blue fluorescence at 460 nm. In a mixture of all eight components of the network, the liberated copper(I) ions were translocated to a macrocycle that catalyzed formation of a rotaxane by a double-click reaction of acetylenic and diazide compounds. The shuttling frequency in the copper-loaded [2]rotaxane was determined to k 298 = 30 kHz (ΔH � = 62.3 � 0.6 kJ mol À 1 , ΔS � = 50.1 � 5.1 J mol À 1 K À 1 , ΔG � 298 = 47.4 kJ mol À 1 ). Removal of zinc(II) ions from the mixture reversed the system back generating the metal-free rotaxane. Further alternate addition and removal of Zn 2 + reversibly controlled the shuttling mode of the rotaxane in this eight-component network where the ion translocation status was monitored by the naked eye.[a] I.

Cooperative Effects in Switchable Catalysis: Enhancing Double‐Click Reaction Yield of Symmetrical Rotaxanes

“…The literature‐known ligand 1 and dimeric complex [Cu 2 ( 1 ) 2 ] 2+ were synthesized according to the established procedures [15] and characterized by 1 H NMR (SI, Figures S1 and S29). When 0.5 equiv of Fe(BF 4 ) 2 were added to the red complex [Cu 2 ( 1 ) 2 ] 2+ (State I), the deep violet complex [FeCu 2 ( 1 ) 2 )] 4+ formed by using exclusively the terminal terpyridine unit for complexation.…”

Kooperative Effekte in schaltbarer Katalyse: Verbesserung der Doppel‐Click‐Reaktionsausbeuten von symmetrischen Rotaxanen

“…Der literaturbekannte Ligand 1 und dimere Komplex [Cu 2 (1) 2 ] 2+ wurden nach etablierten Verfahren synthetisiert [15] und mittels 1 H-NMR charakterisiert (Hintergrundinformationen (HI), Abbildungen S1 und S29). Bei Zugabe von 0.5 ¾quiv.F e(BF 4 ) 2 zum roten Komplex [Cu 2 (1) Nach der Etablierung der Reversibilitätz wischen den Zuständen Iu nd II durch Hinzufügen bzw.E ntfernen von Eisen(II)-Ionen wurde die Effizienz des Systems als schaltbarer Übergangsmetallkatalysator bewertet.…”

“…Der literaturbekannte Ligand 1 und dimere Komplex [Cu 2 ( 1 ) 2 ] 2+ wurden nach etablierten Verfahren synthetisiert [15] und mittels 1 H‐NMR charakterisiert (Hintergrundinformationen (HI), Abbildungen S1 und S29). Bei Zugabe von 0.5 Äquiv.…”

Toward Molecular Cybernetics – the Art of Communicating Chemical Systems

“…The next example demonstrates remote control in a networked eight‐component ensemble where initially the synthesis and later the shuttling of a [2]rotaxane were commanded by metal‐ion translocation [37] . Distinct colorimetric and fluorimetric signals allowed the facile monitoring of the process.…”

“… Three networked states for regulating synthesis and shuttling of a [2]rotaxane [37] . Adapted from ref.…”