Mixed‐Valent Compounds and their Properties – Recent Developments

Launay, Jean‐Pierre

doi:10.1002/ejic.201901180

Cited by 52 publications

(53 citation statements)

References 124 publications

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“… 39 However, the rates of electron transfer typically have an inverse exponential dependence on the distance. 40 For this reason, the shortest donor–acceptor distance, or in this case Sb III ···Sb V distance, is likely to be the most important. While the Sb III ···Sb V distance within each slab (I or III) is approximately 7.50 Å, the interslab (i.e., between I and I′ or III and III′) Sb III ···Sb V distance can be as low as 7.085(3) Å ( Figure 2 e).…”

Section: Resultsmentioning

confidence: 99%

Lone-Pair-Induced Structural Ordering in the Mixed-Valent 0D Metal-Halides Rb₂₃Bi^III_xSb^III_7–xSb^V₂Cl₅₄ (0 ≤ x ≤ 7)

et al. 2021

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Mixed-valent metal-halides containing n s 2 lone pairs may exhibit intense visible absorption, while zero-dimensional (0D) n s 2 -based metal-chlorides are generally colorless but have demonstrated promising optoelectronic properties suitable for thermometry and radiation detection. Here, we report solvothermally synthesized mixed-valent 0D metal-halides Rb 23 Bi III x Sb III 7– x Sb V 2 Cl 54 (0 ≤ x ≤ 7). Rb 23 Sb III 7 Sb V 2 Cl 54 crystallizes in an orthorhombic space group ( Cmcm ) with a unique, layered 0D structure driven by the arrangement of the 5s 2 lone pairs of the Sb III Cl 6 octahedra. This red material is likely the true structure of a previously reported monoclinic “Rb 2.67 SbCl 6 ” phase, the structure of which was not determined. Partially or fully substituting Sb III with isoelectronic Bi III yields the series Rb 23 Bi III x Sb III 7– x Sb V 2 Cl 54 (0 < x ≤ 7), which exhibits a similar layered 0D structure but with additional disorder that yields a trigonal crystal system with an enantiomorphic space group ( R 32). Second harmonic generation of 532 nm light from a 1064 nm laser using Rb 23 Bi III 7 Sb V 2 Cl 54 powder confirms the noncentrosymmetry of this space group. As with the prototypical mixed-valent pnictogen halides, the visible absorption bands of the Rb 23 Bi III x Sb III 7– x Sb V 2 Cl 54 family are the result of intervalent Sb III –Sb V and mixed-valent Bi III –Sb V charge transfer bands (CTB), with a blueshift of the absorption edge as Bi III substitution increases. No PL is observed from this family of semiconductors, but a crystal of Rb 23 Bi III 7 Sb V 2 Cl 54 exhibits a high resistivity of 1.0 × 10 10 Ω·cm and X-ray photoconductivity wi...

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Section: Resultsmentioning

confidence: 99%

Lone-Pair-Induced Structural Ordering in the Mixed-Valent 0D Metal-Halides Rb₂₃Bi^III_xSb^III_7–xSb^V₂Cl₅₄ (0 ≤ x ≤ 7)

et al. 2021

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“…this region provide further confirmation of mixed-valency and delocalization. [140][141][142] Notably, IVCT transitions in this region are characteristic of Class II or Class III mixed-valence complexes, whereby the system is valence trapped (i.e. the redox sites are not energetically identical, but the energetic barrier to for electron transfer is small) or of delocalized valency (i.e.…”

Section: Resultsmentioning

confidence: 99%

Unusually Strong Long-range Electronic Coupling Across Redox-Active Bridges in M3+/M4+ Mixed-Valence Complexes of Group 4 Congeners

Bell

DeYonker

Moore

et al. 2021

Preprint

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Homobimetallic complexes of Group 4 metals, supported by the redox-active tetrakis(imino)pyracene (TIP) ligand were synthesized and isolated. The formation of these complexes resulted in LUMOs having significantly lower energies than the free ligand and the respective metal salts, MCl4 (M = Ti, Zr, Hf), whereby all three complexes were readily reduced by one electron using the mild reductant, Cp*2Fe (E0 = -0.59 V). Spectroscopic characterization and quantum chemical analyses of the reduced species revealed that the resulting complexes are delocalized, borderline Class II-III (Ti) and Class III (Zr, Hf) mixed valence complexes. All three complexes display surprisingly strong long-range electronic coupling between the metal centers, as M to M distances, rAB, are nearly 12 Å. The coupling strengths of Zr and Hf were significantly stronger than those observed for the Ti complex, suggesting that better orbital overlap between the ligand and 4d or 5d metal centers helps to relieve the instability of the 3+ oxidation state via delocalization.

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“…Anal. Calculated (Found) for FeN 4 [M] + , 611.0. Visible spectrum, λ max (nm, ɛ (M À 1 cm À 1 )): 562 (7,320), 209 (37,700).…”

Section: Synthesis and Purificationmentioning

confidence: 99%

“…Metal-alkynyl complexes have been the subject of considerable interest, [1,2] both as models for the study of intramolecular electron transfer, [3,4] and as components in prototypical molecular electronic devices. [5][6][7] The 2 nd and 3 rd row transition metalalkynyl complexes have been studied extensively from the perspectives of both fundamental chemistry [8] and material applications.…”

Section: Introductionmentioning

confidence: 99%

Mono‐ and Bis‐Alkynyl Iron Complexes Supported by a “Softened” Tetraaza Macrocycle

Ren

Clendening

2022

Eur J Inorg Chem

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A pair of novel Fe-alkynyl complexes, [Fe III (HMTI)(C 2 SiEt 3 ) 2 ]ClO 4 (2) and [Fe II (HMTI)(C 2 SiEt 3 )(NCCH 3 )]ClO 4 (3), is described herein. Reaction of Fe(meso-HMC)Cl(ClO 4 )]ClO 4 (1) with lithiated triethylsilylacetylene and subsequent exposure to oxygen yielded the bis-alkynyl 2 containing the dehydrogenated tetraimine macrocycle (HMTI). Reduction of 2 by mossy zinc in acetonitrile yielded the mono-alkynyl 3. The structures of 2 and 3 were determined using single-crystal X-ray diffraction. Analysis of visible absorption and electrochemical data establishes the redox-active nature of the HMTI macrocycle, and indicates significant interactions between the Fe dπ and tetraimine π* orbitals. These deductions are further supported by density functional theory calculations.

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Mixed‐Valent Compounds and their Properties – Recent Developments

Cited by 52 publications

References 124 publications

Lone-Pair-Induced Structural Ordering in the Mixed-Valent 0D Metal-Halides Rb₂₃Bi^III_xSb^III_7–xSb^V₂Cl₅₄ (0 ≤ x ≤ 7)

Lone-Pair-Induced Structural Ordering in the Mixed-Valent 0D Metal-Halides Rb₂₃Bi^III_xSb^III_7–xSb^V₂Cl₅₄ (0 ≤ x ≤ 7)

Unusually Strong Long-range Electronic Coupling Across Redox-Active Bridges in M3+/M4+ Mixed-Valence Complexes of Group 4 Congeners

Mono‐ and Bis‐Alkynyl Iron Complexes Supported by a “Softened” Tetraaza Macrocycle

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Mixed‐Valent Compounds and their Properties – Recent Developments

Cited by 52 publications

References 124 publications

Lone-Pair-Induced Structural Ordering in the Mixed-Valent 0D Metal-Halides Rb23BiIIIxSbIII7–xSbV2Cl54 (0 ≤ x ≤ 7)

Lone-Pair-Induced Structural Ordering in the Mixed-Valent 0D Metal-Halides Rb23BiIIIxSbIII7–xSbV2Cl54 (0 ≤ x ≤ 7)

Unusually Strong Long-range Electronic Coupling Across Redox-Active Bridges in M3+/M4+ Mixed-Valence Complexes of Group 4 Congeners

Mono‐ and Bis‐Alkynyl Iron Complexes Supported by a “Softened” Tetraaza Macrocycle

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Lone-Pair-Induced Structural Ordering in the Mixed-Valent 0D Metal-Halides Rb₂₃Bi^III_xSb^III_7–xSb^V₂Cl₅₄ (0 ≤ x ≤ 7)

Lone-Pair-Induced Structural Ordering in the Mixed-Valent 0D Metal-Halides Rb₂₃Bi^III_xSb^III_7–xSb^V₂Cl₅₄ (0 ≤ x ≤ 7)