Paramagnetic Liquid Crystals With Close π–π Packing: The Effect of Blatter Radical Planarization on Behavior of Bent‐Core Mesogens

Cigl, Martin; Pociecha, Damian; Jakubowski, Rafał; Kapuściński, Szymon; Kaszyński, Piotr

doi:10.1002/chem.202203288

Cited by 5 publications

(5 citation statements)

References 39 publications

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“…For instance, a derivative of Blatter’s radical can be refluxed in chlorobenzene (bp 131 °C) without decomposition and can be heated in the solid phase to ∼270 °C before decomposition begins . Numerous derivatives of the Blatter radical have been recently prepared and their interesting properties studied; − this includes DNP agents for NMR spectroscopy, the magnetically ordered thin film of pyrene–Blatter on SiO 2 /Si substrate that is stable at ambient conditions, − self-assembled films of Blatter radical on Au, paramagnetic liquid crystals of “planarized” Blatter, , batteries, and potential molecular qubits. , Derivatives of the Blatter radical are important building blocks for thermally robust and ultrarobust high-spin di- and triradicals (sections and ). − …”

Section: Persistent and Stable Monoradicals As Spin Centersmentioning

confidence: 99%

From Stable Radicals to Thermally Robust High-Spin Diradicals and Triradicals

Shu,

Yang,

Rajca

2023

Chem. Rev.

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Stable radicals and thermally robust high-spin di-and triradicals have emerged as important organic materials due to their promising applications in diverse fields. New fundamental properties, such as SOMO/HOMO inversion of orbital energies, are explored for the design of new stable radicals, including highly luminescent ones with good photostability. A relation with the singlet−triplet energy gap in the corresponding diradicals is proposed. Thermally robust high-spin di-and triradicals, with energy gaps that are comparable to or greater than a thermal energy at room temperature, are more challenging to synthesize but more rewarding. We summarize a number of high-spin di-and triradicals, based on nitronyl nitroxides that provide a relation between the experimental pairwise exchange coupling constant J/k in the high-spin species vs experimental hyperfine coupling constants in the corresponding monoradicals. This relation allows us to identify outliers, which may correspond to radicals where J/k is not measured with sufficient accuracy. Double helical high-spin diradicals, in which spin density is delocalized over the chiral π-system, have been barely explored, with the sole example of such high-spin diradical possessing alternant π-system with Kekuléresonance form. Finally, we discuss a high-spin diradical with electrical conductivity and derivatives of triangulene diradicals.

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Section: Persistent and Stable Monoradicals As Spin Centersmentioning

confidence: 99%

From Stable Radicals to Thermally Robust High-Spin Diradicals and Triradicals

Shu,

Yang,

Rajca

2023

Chem. Rev.

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“…Additionally, Cigl et al synthesized novel bent-core mesogens based on Blatter radicals 52 and planar periannulated Blatter radicals 53 respectively, and studied their different mesogenic behavior in liquid crystalline phases. [147] After exploring liquid crystalline behavior of 52 and 53, it was found that the planarization of 53 causing close molecular packing, higher mesophases stability and tendency to form various types of ordered phases in liquid crystalline phases. This study also revealed potential applications for functional paramagnetic bentcore mesogens.…”

Section: Triazinyl Radicalsmentioning

confidence: 99%

Neutral Stable Nitrogen‐Centered Radicals: Structure, Properties, and Recent Functional Application Progress

Gao

2023

Adv Funct Materials

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Persistent and stable nitrogen‐centered organic radicals, including non‐heterocyclic/heterocyclic nitrogen‐centered radicals and nitrogen‐centered radical complexes, have attracted much attention due to their special multiple physical properties. Up to now, numerous nitrogen‐centered radical materials have been developed and applied as functional materials in magnetic, electronic, optical, and biologic fields. This review aims to discuss their structural features, physical properties, and recent progress in materials applications. Finally, an outlook providing inspiration for the future development is given.

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“…Recent advances in the design and synthesis of thermally robust high-spin di- and triradicals based on the Blatter radical − have expedited the preparation of organic radical thin films via controlled evaporation under ultrahigh vacuum (UHV). ,− Notable developments include thin films of an S = 1/2 Blatter radical derivative exhibiting magnetic ordering and a high-spin ( S = 1) Blatter-based diradical with robust stability and electrical conductivity . In addition, robustness and synthetic availability of S = 1/2 Blatter radicals enabled their recent applications as paramagnetic liquid crystals, , batteries, and potential molecular spin qubits . Likely, other novel properties will emerge from the remarkable Blatter radical; however, we are in search of new S = 1/2 building blocks for future development.…”

Section: Introductionmentioning

confidence: 99%

Thermally Ultrarobust S = 1/2 Tetrazolinyl Radicals: Synthesis, Electronic Structure, Magnetism, and Nanoneedle Assemblies on Silicon Surface

et al. 2023

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Open-shell organic molecules, including S = 1/2 radicals, may provide enhanced properties for several emerging technologies; however, relatively few synthesized to date possess robust thermal stability and processability. We report the synthesis of S = 1/2 biphenylene-fused tetrazolinyl radicals 1 and 2. Both radicals possess near-perfect planar structures based on their X-ray structures and density-functional theory (DFT) computations. Radical 1 possesses outstanding thermal stability as indicated by the onset of decomposition at 269 °C, based on thermogravimetric analysis (TGA) data. Both radicals possess very low oxidation potentials <0 V (vs. SCE) and their electrochemical energy gaps, E cell ≈ 0.9 eV, are rather low. Magnetic properties of polycrystalline 1 are characterized by superconducting quantum interference device (SQUID) magnetometry revealing a one-dimensional S = 1/2 antiferromagnetic Heisenberg chain with exchange coupling constant J′/k ≈ −22.0 K. Radical 1 in toluene glass possesses a long electron spin coherence time, T m ≈ 7 μs in the 40–80 K temperature range, a property advantageous for potential applications as a molecular spin qubit. Radical 1 is evaporated under ultrahigh vacuum (UHV) forming assemblies of intact radicals on a silicon substrate, as confirmed by high-resolution X-ray photoelectron spectroscopy (XPS). Scanning electron microscope (SEM) images indicate that the radical molecules form nanoneedles on the substrate. The nanoneedles are stable for at least 64 hours under air as monitored by using X-ray photoelectron spectroscopy. Electron paramagnetic resonance (EPR) studies of the thicker assemblies, prepared by UHV evaporation, indicate radical decay according to first-order kinetics with a long half-life of 50 ± 4 days at ambient conditions.

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Paramagnetic Liquid Crystals With Close π–π Packing: The Effect of Blatter Radical Planarization on Behavior of Bent‐Core Mesogens

Cited by 5 publications

References 39 publications

From Stable Radicals to Thermally Robust High-Spin Diradicals and Triradicals

From Stable Radicals to Thermally Robust High-Spin Diradicals and Triradicals

Neutral Stable Nitrogen‐Centered Radicals: Structure, Properties, and Recent Functional Application Progress

Thermally Ultrarobust S = 1/2 Tetrazolinyl Radicals: Synthesis, Electronic Structure, Magnetism, and Nanoneedle Assemblies on Silicon Surface

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