Triple para-Functionalized Cations and Neutral Radicals of Enantiopure Diaza[4]helicenes

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(12), P. 8308 - 8319

Published: March 14, 2024

Modulation of absorbance and emission is key for the design chiral chromophores. Accessing a series compounds absorbing emitting (circularly polarized) light over wide spectral window often toward near-infrared practical value in (chir)optical applications. Herein, by late-stage functionalization on derivatives bridging triaryl methyl helicene domains, we have achieved regioselective triple introduction para electron-donating or electron-withdrawing substituents. Extended tuning electronic (e.g., E1/2red −1.50 V → −0.68 V) optical covering from 550 to 850 nm) properties cations neutral radicals; latter being easily prepared mono electron reductions under electrochemical chemical conditions. While luminescence quantum yields can be increased up 70% cationic series, strong Cotton effects are obtained certain radicals at low energies (λabs ∼ 700–900 with gabs values above 10–3. The open-shell nature was further characterized paramagnetic resonance revealing an important spin density delocalization that contributes their persistence.

Language: Английский

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Spin-State Manipulation in a Luminescent Diradical Polymer

Macromolecules, Journal Year: 2024, Volume and Issue: 57(13), P. 6133 - 6139

Published: June 27, 2024

Controlling the spin states to modulate their optical properties is crucial for spintronics and emerging quantum technologies. Open-shell luminescent diradicals are promising candidates achieving this goal due independent spins. However, spin-optical modulation in traditional still faces significant challenges owing low luminescence efficiency inevitable aggregate effects. In study, we first achieved efficient of a diradical by suspending on polymer main chain. The resulting exhibits high photoluminescence 44.0% condensed state along with excellent photostability. Most importantly, have demonstrated successful spin-state manipulation through temperature control application magnetic field. These findings open up new avenues based materials, providing important guidance development spin-optoelectronics.

Language: Английский

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Engineering Air-Stable Triarylmethyl Radicals with One Pyrrole Ring

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 2, 2025

Herein, seven air-stable triarylmethyl radicals (

Language: Английский

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Multilevel Resonant Tunneling through Purely Organic Radical Molecules in a Si-Based Double-Tunnel Junction

ACS Applied Materials & Interfaces, Journal Year: 2025, Volume and Issue: unknown

Published: April 6, 2025

The use of purely organic radicals is promising, especially for future applications in molecular spintronics. However, the techniques used to form their junctions, including break-junction and scanning tunneling microscopy techniques, are unsuitable integration devices a large-scale setting. In this study, Si-based double-tunnel junction with radicals, where adamantyl nitronyl nitroxide p-terphenyl (NN-TP) molecules embedded as quantum dots oxide layer metal-oxide-semiconductor (MOS) structure, was demonstrated. Notably, MOS structure functions tunnel junction, which has high affinity current Si technology. multilevel resonant through discrete energy levels NN-TP at 7 K achieved; moreover, observed 100 K. Furthermore, our device exhibited singly occupied orbital, indicating survival an unpaired electron radical molecules. Thus, findings hold promise incorporating attractive into solid-state devices, thereby enabling devices.

Language: Английский

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Quantum Spin Transport Through Blatter’s Diradicals and Triradicals

The Journal of Physical Chemistry A, Journal Year: 2025, Volume and Issue: unknown

Published: April 23, 2025

A single unpaired electron in an organic molecule residing the singly occupied molecular orbital (SOMO) renders it radical. It incorporates exchange splitting frontier and unoccupied orbitals, separating α- β-orbitals. This fact enormously impacts transport properties radicals by promoting spin-polarized current significantly enhancing conductance compared to their closed-shell counterparts. Exploring these phenomena, several monoradicals have been investigated through spintronic experiments theories. In this work, we addressed impact of increasing number radical centers on multiradical species considering di- triradicals based a stable Blatter's With centers, SOMOs increases. Does increased provide larger better properties? Here, observed that spatial distributions coupling with electrodes play decisive role presence multiple electrons systems.

Language: Английский

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Long-Range Resonant Charge Transport through Open-Shell Donor–Acceptor Macromolecules

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: May 1, 2025

A grand challenge in molecular electronics is the development of materials that can facilitate efficient long-range charge transport. Research spanning more than two decades has been fueled by prospects creating a new generation miniaturized electronic technologies based on molecules whose synthetic tunability offers tailored properties and functions unattainable with conventional materials. However, current design paradigms produce exhibit off-resonant transport under low bias, which limits conductance to unsatisfactorily levels─several orders magnitude below quantum 1 G0─and often results an exponential decay length. Here, we demonstrate chemically robust, air-stable, highly tunable wire platform comprised open-shell donor-acceptor macromolecules remarkably high close G0 over length surpassing 20 nm no discernible Single-molecule measurements ab initio calculations show ultralong-range resonant arises from extended π-conjugation, narrow bandgap, diradical character, synergistically enables excellent alignment frontier orbitals electrode Fermi energy. The implementation this long-sought-after regime within opportunities for integration manifold emerging nanoelectronic technologies.

Language: Английский

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No More Conductance Decay: Toward Efficient Long-Range Transport in Molecular Wires

ACS Applied Electronic Materials, Journal Year: 2024, Volume and Issue: unknown

Published: April 30, 2024

Molecular electronics has emerged as a highly interdisciplinary field that utilizes single molecules or monolayers functional electronic and sensing components, offering potential capabilities beyond conventional silicon-based electronics. A key mission of the is to search for molecular candidates can facilitate efficient charge transport over long distances. This requires overcoming inherent poor conductivity organic "well-known" conductance decay with increase in length. Recent advances design single-molecule characterizations have sparked exciting opportunities achieving ultrahigh length-independent near-zero inverted attenuation coefficient wires. To highlight this progress, review surveys representative systems, fundamental mechanisms, strategies involved creating conductive wires junction platforms. Through elucidating both chemical physical properties emerging we will an in-depth future investigation promising approaches applications.

Language: Английский

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Zero‐Bias Anti‐Ohmic Behaviour in Diradicaloid Molecular Wires

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(44)

Published: July 14, 2024

Abstract Open‐shell materials bearing multiple spin centres provide a key route to efficient charge transport in single‐molecule electronic devices. They have narrow energy gaps, and their molecular orbitals align closely the Fermi level of metallic electrodes, thus allowing higher conductance. Maintaining stabilising open‐shell states—especially contact with electrodes—is however very challenging, generally requiring continuous chemical or electrochemical potential avoid self‐immolation character. To overcome this issue, we designed, synthesised, measured conductance series bis(indeno) fused acenes, where stability is imparted by close‐shell quinoidal conformation resonance diradical configuration. We show here that these compounds anti‐ohmic behaviour, increasing length, at an unprecedented rate across entire bias window ( ). Density Functional Theory (DFT) calculations support our findings, showing rapidly narrowing HOMO–LUMO gap, unique diradicaloid structures, responsible for observed behaviour. Our results framework achieving neutral demonstrate promise electronics, owing great structure.

Language: Английский

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Tailoring Charge-Transfer at Metal–Organic Interfaces Using Designer Shockley Surface States

The Journal of Physical Chemistry Letters, Journal Year: 2025, Volume and Issue: unknown, P. 4081 - 4089

Published: April 16, 2025

Metal-organic interfaces determine critical processes in organic electronic devices. The frontier molecular orbitals (highest occupied and lowest unoccupied orbital, HOMO LUMO) are crucial determining charge-injection charge-collection into from the semiconductor films. Here we show that able to tune interfacial structure of a strongly interacting system formed by adsorption electron acceptor 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HATCN, C18N12) on Ag thin films Cu(111). thickness-dependent Shockley surface state emerging this layered metallic couples LUMO, which allows precise control over energetic position filling charge-transfer interface relative Fermi level (EF). Our ability while maintaining film represents an important step toward designing interfaces.

Language: Английский

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Single-Molecule Conductance of Neutral Closed-Shell and Open-Shell Diradical Indenofluorenes

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(43), P. 29977 - 29986

Published: Oct. 18, 2024

Organic diradicals are highly promising candidates as future components in molecular electronic and spintronic devices because of their low spin-orbit coupling. To advance toward final circuit realizations, a thorough knowledge the behavior within single-molecule junction framework is imperative. In this work, we have measured for first time conductance neutral open-shell diradical compound, [2,1-

Language: Английский

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