A monomer–dimer nanoswitch that mimics the working principle of the SARS-CoV 3CLpro enzyme controls copper-catalysed cyclopropanation

Abstract

A triangular framework with a terpyridine and shielded phenanthroline at its termini constitutes an open/close nanoswitch that is toggled by chemical inputs. In the presence of copper(I) ions, the open triangular framework (OPEN-I) firmly closes to a catalytically inactive heteroleptic [Cu(phen)(terpy)](+) complex (CLOSE). Reversible switching between CLOSE and OPEN-I states was demonstrated by successive addition and removal of Cu(+). In contrast, after addition of iron(II) ions to the CLOSE state a bishomoleptic dimeric [Fe(terpy)2](2+) complex is formed with the copper(I) ions placed in the phenanthroline cavities (OPEN-II). Due to its coordinatively unsaturated [Cu(Phen)](+) sites the dimeric iron complex is able to serve as a catalyst in the cyclopropanation of Z-cyclooctene using ethyl diazoacetate.

Heteroleptic copper phenanthroline complexes in motion: From stand-alone devices to multi-component machinery

“…Upon addition of copper(I) ions the hybrid terpyridinephenanthroline ligand 19 readily forms the intramolecular copper complex [Cu (19)] + (State I in Fig. 12), a process that is easily reverted back to 19 upon adding one equivalent of cyclam [34]. This cycle was repeated several times.…”

“…In complex [Fe(Cu) 2 (19) 2 ] 4+ the copper(I) ions in the shielded phenanthroline sites remain coordinatively unsaturated, a feature that was exploited for catalyzing the cyclopropanation of cyclooctene (20) with ethyl diazoacetate (21) [34]. When nanoswitch [Cu (19)] + (= State I) was heated (55°C for 4 h) together with the above reactants ([Cu (19)] + , 20 and 21 = 1:10:10), no transformation was detected ( Fig.…”

Dynamic Functional Molecular Systems: From Supramolecular Structures to Multi‐Component Machinery and to Molecular Cybernetics

“… Double self‐sorting leads to catalytic machinery in NetState II, in which the 46 kHz‐nanorotor [Cu 2 ( 34 )( 23 a )] 2+ acts as catalyst in a click reaction …”

“…Importantly, the above self-sorting events (Scheme 5) are not perturbed in presence of reactants 35 and 36. [48] When NetState I was generated, no transformation 35 + 36!37 was observed, however, after formation of NetState II, the nanorotor [Cu 2 (34)(23 a)] 2 + acted as a catalyst for the click reaction of 35 + 36 producing 37. Showing high reproducibility, the full machinery delivered identical yields of product 37 (36 %) and ON/OFF behavior in two subsequent cycles.…”

Ein metallregulierter vierstufiger Nanoschalter zur Steuerung einer zweistufigen sequenziellen Katalyse in einem Elf‐Komponenten‐System

“…Für den vierstufigen Schalter 1 (Abbildung ) haben wir eine andere Architektur als für unsere früheren Nanoschalter gewählt, die ihre Fähigkeit zur AN/AUS‐Regulation bereits in photochemischen Prozessen sowie in der Organo‐ und Übergangsmetall‐Katalyse bewiesen haben ,. Schalter 1 basiert auf dem höchst vielseitigen Tetraphenylmethan‐Gerüst und ist mit drei Armen und drei unterschiedlichen Termini ausgestattet: einer Zink(II)‐porphyrin(ZnPor)‐Einheit, einem Azaterpyridin(azaterpy)‐Arm, der zwei funktionale Liganden enthält, und einem abgeschirmten Phenanthrolin.…”