Decacyclene Radical Anions Showing Strong Low‐energy Intramolecular Absorption and Magnetic Coupling of Spins in a Hexagonal Network

Konarev, Dmitri V.; Kuzmin, Alexey V.; Khasanov, Salavat S.; Shestakov, Alexander F.; Otsuka, Akihiro; Yamochi, Hideki; Kitagawa, Hiroshi; Lyubovskaya, Rimma N.

doi:10.1002/asia.202000615

Cited by 9 publications

(7 citation statements)

References 42 publications

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“…Further reduction was carried out by a stronger reductant such as cesium anthracene. The anthracene radical anion (C 10 H 14 •– ) has a first oxidation potential of −1.95 V vs. SCE 14 and is unstable in o -dichlorobenzene . Therefore, toluene was used as a solvent because it does not interact with cesium anthracene.…”

Section: Resultssupporting

confidence: 87%

Dianionic States of Trithiadodecaazahexaphyrin Complexes with Homotrinuclear M^II₃O Clusters (M = Ni and Cu): Crystal Structures, Metal- Or Macrocycle-Centered Reduction, and Doublet–Quartet Transitions in the Dianions

et al. 2021

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Metal complexes of trithiadodecaazahexaphyrin (Hhp) that contain M II 3 O clusters inside a π-extended trianionic (Hhp 3− ) macrocycle have been prepared. Studies of the magnetic properties of Ni II 3 O(Hhp) and Cu II 3 O(Hhp) reveal a diamagnetic and EPR-silent trianionic (Hhp 3− ) macrocycle and diamagnetic Ni II 3 (O 2− ) or paramagnetic Cu II 3 (O 2− ) tetracations. The positive charge of M II 3 O(Hhp) is compensated by one acetate anion {M II 3 O(Hhp)} + (CH 3 CO 2 − ). The three-electron reduction of {M II 3 O(Hhp)} + yields {cryptand 2) crystalline salts. The magnetic properties of 1 reveal the formation of Hhp 5− and the reduction of nickel(II) to the paramagnetic Ni I ion (S = 1/2), which is accompanied by the formation of the {Ni II 2 Ni I O(Hhp 5− )} 2− dianion. As a result, the magnetic moment of 1 is 1.68 μ B in the 20−220 K range, and a broad EPR signal of Ni I was observed. The Hhp 5− macrocycle has a singlet ground state, but the increase in the magnitude of the magnetic moment of 1 above 220 K is attributed to the population of the triplet excited state in Hhp 5− . The {Ni II 2 Ni I O(Hhp 5− )} 2− dianion is transferred from the doublet excited state to the quartet excited state with an energy gap of 1420 ± 50 K. Salt 1 also shows an unusually strong low-energy NIR absorption, which was observed at 1000−2200 nm. In 2, a highly reduced Hhp •6− radical hexaanion (S = 1/2) coexists with a Cu II 3 (O 2− ) cluster (S = 1/2) in the {Cu II 3 O(Hhp •6− )} 2− dianions. The dianions have a triplet ground state with antiferromagnetic exchange between two S = 1/2 spins with J = −6.4 cm −1 . The reduction of Hhp in both salts equalizes the initially alternated C−N bonds, supporting the increase in the Hhp macrocycle electron delocalization.

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Section: Resultssupporting

confidence: 87%

Dianionic States of Trithiadodecaazahexaphyrin Complexes with Homotrinuclear M^II₃O Clusters (M = Ni and Cu): Crystal Structures, Metal- Or Macrocycle-Centered Reduction, and Doublet–Quartet Transitions in the Dianions

et al. 2021

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“…Compound E7 features triangular lattice (Figure 11b) with strong distortion owing to the Jahn-Teller effect. Curie-Weiss fitting for the magnetic susceptibility curve of E7 resulted in a Weiss constant of À 11 K, [81] with the absence of magnetic order down to 1.9 K. In addition, E7 exhibits strong near-infrared (NIR) absorption (at 4800 cm À 1 ) attributed to the SOMO! LUMO + 1 transition.…”

Section: Methodsmentioning

confidence: 99%

“…Examples of spin‐frustrated PAHs include the phenanthrene salt Cs(C 14 H 10 ) ( E6 , Figure 11a) reported by Prassides et al., [80] the decacyclene salt (cryptand[2.2.2](Cs + ))(decacyclene⋅ − ) ( E7 , Figure 11b) isolated by Konarev et al., [81] and the triply negatively charged nanographene bilayer ( E8 , Figure 12) discovered by us very recently [82] . The calculated frustration parameters of E6 − E8 are listed in Table 2.…”

Section: Intermolecular Spin Frustrationmentioning

confidence: 99%

Spin Frustration in Organic Radicals

Tang,

Wang

2023

Angew Chem Int Ed

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Spin frustration, resulted from geometric frustration and a systematical inability to satisfy all antiferromagnetic (AF) interactions between the unpaired spins simultaneously, is under spotlight for its importance in physics and materials science. Spin frustration is treated as structural basis of quantum spin liquid (QSL). Featuring flexible chemical structures, organic radical species exhibit great potential in building spin‐frustrated molecules and lattices. Until now, the reported examples of spin‐frustrated organic radical compounds include triradicals, tetrathiafulvalene (TTF) radicals and derivatives, [Pd(dmit)2] compounds (dmit = 1,3‐dithiol‐2‐thione‐4,5‐dithiolate), nitronyl nitroxides, fullerenes, polycyclic aromatic hydrocarbons (PAHs), and other heterocyclic compounds, where the spin frustration is generated intra‐ or intermolecularly. In this Minireview, we provide a brief summary for the reported radical compounds possess spin frustration. The related data, including magnetic exchange coupling parameters, spin models, frustration parameters, and crystal lattices, are summarized and discussed.

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“…Sodium fluorenone ketyl was obtained as described [48] . Cesium anthracenide, (Cs + )(C 14 H 10 ⋅ − ), was obtained as described [49] . Solvents were purified under argon atmosphere.…”

Section: Methodsmentioning

confidence: 99%

“…[48] Cesium anthracenide, (Cs + )(C 14 H 10 *À ), was obtained as described. [49] Solvents were purified under argon atmosphere. o-Dichlorobenzene (C 6 H 4 Cl 2 ) was distilled over CaH 2 under reduced pressure.…”

Section: Experimental Section Materialsmentioning

confidence: 99%

Crystalline Rhodium‐Tin Complexes with Radical Trianion and Tetraanion Phthalocyanine Ligands: Observation of N_imine(Pc)−Rh Coordination Bond

Faraonov,

Kuzmin,

Yakushev

et al. 2023

Eur J Inorg Chem

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Crystalline complexes {Cryptand(Na+)}[(COD)RhICl×SnII(Pc·3‐)]‐×2C6H4Cl2 (1) and {Cryptand(Cs+)}[(COD)RhI×SnII(Pc4‐)]‐×C7H8 (2) were obtained via the interaction of [SnII(Pc·3‐)]‐ and [SnII(Pc4‐)]2‐, respectively, with {(COD)RhCl}2 dimer (COD is 1,5‐cycrooctadiene). Dissociation of {(COD)RhCl}2 followed by the Rh‐Sn binding is observed at the formation of 1. Elimination of the chlorine atom at the rhodium atom is observed in 2, and rhodium is additionally coordinated to the imine nitrogen atom of Pc4‐. The complexes contain mono‐ Pc·3‐ and doubly reduced Pc4‐ species, respectively, that is supported by the data of XRD analysis as well as optical and magnetic properties of 1 and 2. There is an alternation of C‐Nimine bonds in the macrocycles, which gradually increases with increasing negative charge on the macrocycle. The formation of 1 and 2 is accompanied by gradual blue shifts of the Q‐band of starting SnPc. The value of effective magnetic moment of 1 is 1.76 mB at 300 K corresponding the contribution of the Pc·3‐ radical trianions (S = 1/2). Only weak magnetic coupling with the Weise temperature of ‐3 K is observed in 1 due to weak π‐π interaction between the macrocycles in the chains. Complex 2 is diamagnetic and EPR silent.

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Decacyclene Radical Anions Showing Strong Low‐energy Intramolecular Absorption and Magnetic Coupling of Spins in a Hexagonal Network

Cited by 9 publications

References 42 publications

Dianionic States of Trithiadodecaazahexaphyrin Complexes with Homotrinuclear M^II₃O Clusters (M = Ni and Cu): Crystal Structures, Metal- Or Macrocycle-Centered Reduction, and Doublet–Quartet Transitions in the Dianions

Dianionic States of Trithiadodecaazahexaphyrin Complexes with Homotrinuclear M^II₃O Clusters (M = Ni and Cu): Crystal Structures, Metal- Or Macrocycle-Centered Reduction, and Doublet–Quartet Transitions in the Dianions

Spin Frustration in Organic Radicals

Crystalline Rhodium‐Tin Complexes with Radical Trianion and Tetraanion Phthalocyanine Ligands: Observation of N_imine(Pc)−Rh Coordination Bond

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Decacyclene Radical Anions Showing Strong Low‐energy Intramolecular Absorption and Magnetic Coupling of Spins in a Hexagonal Network

Cited by 9 publications

References 42 publications

Dianionic States of Trithiadodecaazahexaphyrin Complexes with Homotrinuclear MII3O Clusters (M = Ni and Cu): Crystal Structures, Metal- Or Macrocycle-Centered Reduction, and Doublet–Quartet Transitions in the Dianions

Dianionic States of Trithiadodecaazahexaphyrin Complexes with Homotrinuclear MII3O Clusters (M = Ni and Cu): Crystal Structures, Metal- Or Macrocycle-Centered Reduction, and Doublet–Quartet Transitions in the Dianions

Spin Frustration in Organic Radicals

Crystalline Rhodium‐Tin Complexes with Radical Trianion and Tetraanion Phthalocyanine Ligands: Observation of Nimine(Pc)−Rh Coordination Bond

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Product

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Dianionic States of Trithiadodecaazahexaphyrin Complexes with Homotrinuclear M^II₃O Clusters (M = Ni and Cu): Crystal Structures, Metal- Or Macrocycle-Centered Reduction, and Doublet–Quartet Transitions in the Dianions

Dianionic States of Trithiadodecaazahexaphyrin Complexes with Homotrinuclear M^II₃O Clusters (M = Ni and Cu): Crystal Structures, Metal- Or Macrocycle-Centered Reduction, and Doublet–Quartet Transitions in the Dianions

Crystalline Rhodium‐Tin Complexes with Radical Trianion and Tetraanion Phthalocyanine Ligands: Observation of N_imine(Pc)−Rh Coordination Bond