(Nano)mechanical Motion Triggered by Metal Coordination: from Functional Devices to Networked Multicomponent Catalytic Machinery

Abstract

A look at the elegance and efficiency of biological machines readily reveals that Nature masters the full gamut of chemical interactions to compose masterpieces of the living world. The present analysis singles out metal coordination for the actuation of nanomechanical motion. According to our analysis, metal coordination has a manifold of rewards, putting it primo loco in opportunities for putting nanomechanical systems into action: (i) its strength and dynamics can be properly modulated and fine-tuned by the choice of metal, redox state, and ligand(s), (ii) the high directionality of the interaction allows reliable design, and (iii) the emergence of novel self-sorting algorithms allows multiple of these interactions to be working in parallel. On top of all these advantages, intermolecular metal-ion translocation is a well-known factor in biological signaling. These benefits have recently proven their usefulness in the operation of networked devices and in overcoming the limitations of traditional stand-alone molecular systems.

Helicates with Ether‐Substituted Catechol Esters as Ligands

“…2,3-Bis(benzyloxy)benzoic acid was prepared according to a literature procedure. [1] Moisture or oxygen intrinsic phasing (SHELXT). The structures were refined using SHELXL-201813 with a least-squares procedure against F 2 .…”

“…were added subsequently and the reaction mixture was stirred at 25°C for 48 h. Upon completion, the solvent was removed under reduced pressure and the crude product was purified by column chromatography (SiO 2 , 3:2 pentane/ethyl acetate) to afford the title compound (544 mg, 0.69 mmol, 63 %) as a white solid. 1 4d-H 4 . The ligand was prepared applying the general procedure for removal of benzyl protecting groups (see 4a-H 4 ) starting form 4dII (600 mg, 0.66 mmol) to afford the title compound (138 mg, 0.39 mmol, 59 %) as a white solid.…”

“…The product was prepared applying the general procedure for the preparation of THP protected diols (see 5aIII) starting form 5bII (540 mg, 2.15 mmol) to afford the title compound (462 mg, 1.10 mmol, 90 %) as a white solid. 1 5b-H 4 . The ligand was prepared applying the general procedure for removal of benzyl protecting groups (see 4a-H 4 ) starting form 5bIV (100 mg, 0.12 mmol) to afford the title compound (142 mg, 0.27 mmol, 75 % as colorless oil.…”

“…Dynamic behavior of the obtained supramolecular aggregates, which ideally can be controlled by some external stimuli, leads into the world of molecular devices like machines or switches. [1] Many chemical devices have been prepared e.g. based on rotaxane and catenane motifs, but other structural moieties have been successfully used as well.…”

“…The product was prepared applying the general procedure for diol esterification (see 4aII) starting form tetraethylene glycol 4bI (200 mg, 1.03 mmol) to afford the title compound (468 mg, 0.56 mmol, 55 %) as a white solid 1. H-NMR (600 MHz, [D 6 ]DMSO): δ = 7.49-7.45 (m, 4H, 4H arom.…”