Synthesis of a Copper [3]Rotaxane Able To Function as an Electrochemically Driven Oscillatory Machine in Solution, and To Form SAMs on a Metal Surface

Abstract

Two new copper [3]rotaxanes have been synthesized. The axes are identical for both compounds and incorporate two bidentate chelates joined together by a disulfide bridge. The rings contain either the single phen (phen = 1,10-phenanthroline) chelate or two different chelates (phen and terpy; terpy = 2,2',6',2' '-terpyridine, a tridentate chelate). The key intermediates for both synthetic routes are semi-rotaxanes obtained in high yields using the three-dimensional effect of copper(I). In the case where the wheels are heterobischelating macrocycles, large molecular motions, namely rotation or oscillation of the wheels around the axle, have been induced electrochemically. Anchoring of these two copper [3]rotaxanes on a gold electrode was carried out by standard procedures. Cleavage of the disulfide bridge and formation of monolayers of rotaxanes were evidenced by cyclic voltammetry. The adsorbed rotaxanes can be viewed as copper [2]rotaxanes for which the gold electrode surface acts as a stopper linked to one end of their axes.

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

“…ð½CuðphenÞÞ þ=2þ bond cleavage of surface-bound rotaxanes and catenanes ( Fig. 9) [20,21]. Unfortunately, e.g.…”

“…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.…”

Driving Smart Molecular Systems by Artificial Molecular Machines

“…In biological systems, ATP synthase and bacterial flagella are immobilized on the cell membrane to ensure stable operation and energy transfer, which has inspired researchers to mount AMMs on solid surfaces to improve performance . In 2003, Sauvage and coworkers constructed copper [3]rotaxanes with a disulfide bridge in the molecule center, using the Cu(I) template effect and oxidative coupling to afford semirotaxanes and mounting them on a gold surface. Stoddart and coworkers designed a nanomechanical device containing an array of microcantilever beams coated with a self‐assembled monolayer (SAM) of bistable [3]rotaxanes.…”

Templated Synthesis of Interlocked Molecules

“…Molecular design motifs based on intramolecular disulfide bonding have been incorporated into a series of rotaxanes [289] and catenates [282] in order to facilitate their self-assembly onto gold surfaces. However, in both cases, the 10 The interlocked macrocycle of a surface-bound bistable [2]rotaxane 94 displays electrochemically driven linear motions between two recognition sites.…”