Distinctive features and challenges in catenane chemistry

Au‐Yeung, Ho Yu; Deng, Yulin

doi:10.1039/d1sc05391d

Cited by 36 publications

(43 citation statements)

References 349 publications

(135 reference statements)

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“…Since the "zip-tie" approach with a single central ring combined with preformed macrocycles or [2]catenanes is designed to minimize the number of necessary ring-closing events, and thus reduce the likelihood of generating unwanted byproducts, higher yielding syntheses were anticipated. However, an obvious dichotomy exists between the combined overall yields obtained for catenanes [5]C (15%) and [3]C (36%), where each yield includes metalation, self-assembly, RCM, and demetalation but excludes the steps required to make the premade macrocycle and [2]catenane end-caps. We speculate the difference in yields for this head-to-head comparison largely stems from the relative stability of the respective precatenate complexes during the RCM step, which in principle should be the same for each mechanical bondforming reaction due to the commonality of the approach and central macrocycle 1.…”

Section: Resultsmentioning

confidence: 99%

“…These include metal-coordination, 8 donor−acceptor, 9 hydrogen-bonding, 10 and anion−dipole 11 interactions, to name some. For example, Stoddart and coworkers capitalized on charge-transfer interactions between π-electron-deficient and -rich macrocycles to successfully synthesize a linear [5]catenane they called "Olympiadane". 12,13 More recently, Iwamoto and co-workers used hydrogen bonding to template the synthesis of another linear [5]catenane.…”

Section: ■ Introductionmentioning

confidence: 99%

“…For example, Stoddart and coworkers capitalized on charge-transfer interactions between π-electron-deficient and -rich macrocycles to successfully synthesize a linear [5]catenane they called "Olympiadane". 12,13 More recently, Iwamoto and co-workers used hydrogen bonding to template the synthesis of another linear [5]catenane. 14 To date, both of these examples have stood as the record for the total number of interlocked macrocycles isolated as a linear, unimolecular oligo[n]catenane, even though Stoddart and co-workers did report by mass spectrometry a linear [7]catenane that was never isolated.…”

Section: ■ Introductionmentioning

confidence: 99%

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Topologically Controlled Syntheses of Unimolecular Oligo[n]catenanes

et al. 2022

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Catenanes are a well-known class of mechanically interlocked molecules that possess chain-like architectures and have been investigated for decades as molecular machines and switches. However, the synthesis of higher-order catenanes with multiple, linearly interlocked molecular rings has been greatly impeded by the generation of unwanted oligomeric byproducts and figure-of-eight topologies that compete with productive ring closings. Here, we report two general strategies for the synthesis of oligo[n]catenanes that rely on a molecular “zip-tie” strategy, where the “zip-tie” is a central core macrocycle precursor bearing two phenanthroline (phen) ligands to make odd-numbered oligo[n]catenanes, or a preformed asymmetric iron(II) complex consisting of two macrocycle precursors bearing phen and terpyridine ligands to make even-numbered oligo[n]catenanes. In either case, preformed macrocycles or [2]catenanes are threaded onto the central “zip-tie” core using metal templation prior to ring-closing metathesis (RCM) reactions that generate several mechanical bonds in one pot. Using these synthetic strategies, a family of well-defined linear oligo[n]catenanes were synthesized, where n = 2, 3, 4, 5, or 6 interlocked molecular rings, and n = 6 represents the highest number of linearly interlocked rings reported to date for any isolated unimolecular oligo[n]catenane.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Topologically Controlled Syntheses of Unimolecular Oligo[n]catenanes

et al. 2022

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“…31 These MSTJ devices show remnant molecular electronic signatures and nonvolatile memory effects in high-density integrated circuits. 31−38 Numerous excellent reviews have been published covering different kinds of MIMs, i.e., bistable rotaxanes, 39 switchable catenanes, 40 interlocked daisy chains, 41 and artificial molecular machines. 42 In this Review, we summarize briefly the properties of MIMs and then focus on recent developments in mechanically interlocked molecular junctions (MIMJs).…”

Section: Introductionmentioning

confidence: 99%

A Roadmap for Mechanically Interlocked Molecular Junctions at Nanoscale

Yang

Chen

2022

ACS Appl. Nano Mater.

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The beauty and utility of mechanically interlocked architectures have received considerable notice from scientists in the past several decades. Plentiful scientific and technological achievements have been made and developed because of conjoining mechanically interlocked molecules (MIMs) and molecular electronic devices at nanoscale. The interaction mechanisms and translational dynamics of various MIMs, e.g., rotaxanes, catenanes, and daisy chains, have been investigated systemically through different experimental methods. On account of the recent advances of single-molecule techniques, the electrical and mechanical performance of mechanically interlocked molecular junctions (MIMJs) or nanodevices have been explored in a timely manner. In this Review, we survey the field of MIMs from a perspective of unique structural properties including topological features, translational dynamics, bistable switching properties, insulation effects, and dynamic stability present in MIMs. We then give a fundamental description of electron transport mechanisms in MIMJs for three different nanodevice geometries: (i) monolayer switching tunnel junctions (MSTJs), (ii) single-molecule junctions (SMJs) based on MIMs, and (iii) real-time transistor-like platforms.

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“…39 Catenane is a class of mechanically interlocked molecules (MIMs) that consist of interlocked macrocycles. [40][41] Mechanical interlocking holds the catenane in place as a single molecule, and yet endows the interlocked macrocycles a high degree of motional freedom, and such unique features could be an effective mimic of the kinetic features of metallo-oxygenases for developing molecular ORR catalysts (Fig. 1a).…”

Section: Introductionmentioning

confidence: 99%

Mechanical Interlocking Enhances the Electrocatalytic Oxygen Reduction Activity and Selectivity of Molecular Copper Complexes

Deng

Lai

et al. 2022

Preprint

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Efficient O2 reduction reaction (ORR) for selective H2O generation enables advanced fuel cell technology. Non-precious metal (NPM) catalysts are viable and attractive alternatives to state-of-the-art Pt-based materials that are expensive. Cu complexes inspired by Cu-containing O2 reduction enzymes in nature have yet to reach their desired ORR catalytic performance. Here, the concept of mechanical interlocking is introduced to the ligand architecture to enforce dynamic spatial restriction on the Cu coordination site unachievable using other structural means. The utility of the kinetic effects from mechanical bond in transition metal catalysis is just about to emerge, and here the catenane ligands govern the O2 adduct binding mode, thereby steering the selectivity to generate H2O as the major product via the 4e– pathway, rivaling the selectivity of Pt. The kinetic effects from the interlocked catenane ligand also promotes product elimination and boosts the onset potential by 130 mV, the mass activity by 1.8 times, and the turnover frequency (TOF) by 1.5 folds as compared to the non-interlocked counterpart. Our Cu catenane complex represents one of the first examples to take advantage of mechanical interlocking to afford electrocatalysts with enhanced activity and selectivity. The mechanistic insights gained through this integrated experimental and theoretical study are envisioned to be of practical value not just to the area of ORR energy catalysis, but also with broad implications on interlocked metal complexes that are of critical importance to the general fields in redox reactions involving proton-coupled electron transfer (PCET) steps

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Distinctive features and challenges in catenane chemistry

Abstract: From being an aesthetic molecular object to a building block for the construction of molecular machines, catenane and related mechanically interlocked molecules (MIMs) continue to attract immense interest in many...

Cited by 36 publications

References 349 publications

Topologically Controlled Syntheses of Unimolecular Oligo[n]catenanes

Topologically Controlled Syntheses of Unimolecular Oligo[n]catenanes

A Roadmap for Mechanically Interlocked Molecular Junctions at Nanoscale

Mechanical Interlocking Enhances the Electrocatalytic Oxygen Reduction Activity and Selectivity of Molecular Copper Complexes

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