Dynamic control of chirality and self-assembly of double-stranded helicates with light

Abstract

Helicity switching in biological and artificial systems is a fundamental process that allows for the dynamic control of structures and their functions. In contrast to chemical approaches to responsive behaviour in helicates, the use of light as an external stimulus offers unique opportunities to invert the chirality of helical structures in a non-invasive manner with high spatiotemporal precision. Here, we report that unidirectional rotary motors with connecting oligobipyridyl ligands, which can dynamically change their chirality upon irradiation, assemble into metal helicates that are responsive to light. The motor function controls the self-assembly process as well as the helical chirality, allowing switching between oligomers and double-stranded helicates with distinct handedness. The unidirectionality of the light-induced motion governs the sequence of programmable steps, enabling the highly regulated self-assembly of fully responsive helical structures. This discovery paves the way for the future development of new chirality-dependent photoresponsive systems including smart materials, enantioselective catalysts and light-driven molecular machines.

Stereodivergent Anion Binding Catalysis with Molecular Motors

“…These species are pseudoenantiomers, only differing from each other in the handedness of the helical structure. In the presence of chloride anions, ( R , R )‐( M , M )‐ cis ‐ 1 and ( R , R )‐( P , P )‐ cis ‐ 1 can form a supramolecular helical assembly to give rise to ( R , R )‐( M , M )‐ cis ‐ 1‐Cl and ( R , R )‐( P , P )‐ cis ‐ 1‐Cl , respectively, whose configuration would be dictated by the helicity of the motor backbone . We envisioned that this transfer and amplification of chiral information from the molecular to the supramolecular level could be exploited to achieve the preferential formation of different stereoisomers in the context of asymmetric anion binding catalysis depending upon the external stimulus applied.…”

Toward Fast and Efficient Visible‐Light‐Driven Molecular Motors: A Minimal Design

“…The first synthetic light‐driven rotary molecular motors, based on sterically overcrowded alkenes, were developed in the late 1990s and have subsequently attracted considerable interest, both in terms of improving the performance of these motors and in exploiting the mechanical motion that they produce for useful applications . Under ambient conditions, the intrinsic rotational frequencies attainable by freely floating (in solution) overcrowded‐alkene motors are limited in two different ways.…”

Helical Inversion of Peptide‐based Supramolecular Co2+ Complexes

“…[4][5][6][7][8][9][10] Furthermore, an extensive range of synthetic systems exhibit helical conformations. [26][27][28][29][30][31][32][33] Various specific noncovalent intermolecular interactions have been exploited to construct such supramolecular assemblies. Examples of synthetic systems that exhibit environmentresponsive helical switching include the solvent-dependent inversion of helical metal complexes 14,15 and dialkylpolysilanes 16 as well as the temperature-induced helicity inversion of switchable polyacetylenes, [17][18][19][20][21] polydiarylsilanes, 22 and polyisocyanates, 23-25 among others.…”