Interconversion of Metallabenzenes and Cyclic η<sup>2</sup>‐Allene‐Coordinated Complexes

Lin, Ran; Zhao, Jing; Chen, Hanyu; Zhang, Hong; Xia, Haiping

doi:10.1002/asia.201200231

Cited by 24 publications

(10 citation statements)

References 106 publications

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“…The Os1=N1 bond length (1.806(10) Å) is within the typical range of bond lengths for azavinylidene–osmium complexes (1.777–1.881 Å),–– and the N1=C4 bond length (1.261(15) Å) is in the expected range for C=N double‐bond lengths. The Os1−C1 (2.095(11) Å) and C1=C2 (1.350(16) Å) bond lengths are similar to those found in other osmium–vinyl metallacycles and support the presence of a vinyl moiety. In contrast to the metallacycles in 2 a and 3 a , that in complex 4 a clearly deviates from planarity, which is reflected by the sum of the angles in the six‐membered ring (713.4°).…”

Section: Resultssupporting

confidence: 73%

Synthesis of Cyclic Vinylidene Complexes and Azavinylidene Complexes by Formal [4+2] Cyclization Reactions

Chen

Huang

Lü

et al. 2016

Chemistry A European J

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Reactions of the hydrido-butenylcarbyne complex [OsHCl2(≡CC(PPh3)=CHEt)(PPh3)2]BF4 (1) with nitriles RC≡N (R=2-cyclopropyl-2-oxopropyl, 3-amino-2-oxobutyl) lead to six-membered cyclic vinylidene complexes 3 and azavinylidene complexes 4, that is, iso-osmapyridiniums. Treatment of 1 with excess 2-formylbenzonitrile at reflux temperature in CHCl3 in the presence of air produces a fused osmapyridinium 8, which is first oxidized to the tricyclic iso-osmapyridinium derivative 7, then to iso-osmapyridinium 9, which contains a fused naphthalenone fragment. The conversion of iso-osmapyridinium 9 (with a vinylidene segment) to the iso-osmapyridinium compounds 10 and 11 (with azavinylidene segments) was achieved in the presence of a hydrogen halide, such as HCl or HI. The molecular structures of the complexes synthesized were confirmed by X-ray studies. Moreover, the aromatic stabilization energy and nucleus-independent chemical-shift values of the osmapyridiniums and the strain in the iso-osmapyridinium rings were investigated by DFT calculations.

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Section: Resultssupporting

confidence: 73%

Synthesis of Cyclic Vinylidene Complexes and Azavinylidene Complexes by Formal [4+2] Cyclization Reactions

Chen

Huang

Lü

et al. 2016

Chemistry A European J

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“…148,149,454 Similar substitution reactions have also been found in osmabenzenes. 134,136,455 Moreover, Xia et al found that, when L-cysteine was added into an aqueous solution of 473 at physiological pH 7.4, two diastereomeric isomers (Λ Ru , R C )-474 and (Δ Ru , R C )-474 were generated. From the results of CD (circular dichroism) spectroscopy, NMR spectroscopy, and X-ray crystal structures, the authors speculated that (Λ Ru , R C )-474 is the thermodynamic product, while (Δ Ru , R C )-474 is the kinetic product, and the ratios are dependent on the pH values (Scheme 151).…”

Section: Reactivities Of Metallabenzenesmentioning

confidence: 99%

“…466 Such reactions were further extended to an osmabenzene. 455 Intramolecular nucleophilic substitution reactions have also been reported. For example, when complex 29 was treated with NaOMe, osmabenzothiazole 515 was isolated.…”

Section: Electrophilic Substitution Of Metallabenzenesmentioning

confidence: 99%

“…Another related osmabenzene was observed to exhibit a similar reactivity as 512. 455 The same group developed several electrophilic cyclization reactions. Treatment of osmabenzene 352 with I 2 gave complex 566 (Scheme 179).…”

Section: Electrophilic Substitution Of Metallabenzenesmentioning

confidence: 99%

“…For example, the PPh 3 groups in ruthenabenzene 63 could be displaced by PBu 3 , one of the Cl – could be substituted by t -BuNC, and one Cl – together with one PPh 3 could be replaced by the bidentate ligand 1,10-phenanthroline, giving products 471 – 473 , respectively (Scheme ). ,, Similar substitution reactions have also been found in osmabenzenes. ,, Moreover, Xia et al found that, when l -cysteine was added into an aqueous solution of 473 at physiological pH 7.4, two diastereomeric isomers (Λ Ru , R C )- 474 and (Δ Ru , R C )- 474 were generated. From the results of CD (circular dichroism) spectroscopy, NMR spectroscopy, and X-ray crystal structures, the authors speculated that (Λ Ru , R C )- 474 is the thermodynamic product, while (Δ Ru , R C )- 474 is the kinetic product, and the ratios are dependent on the pH values (Scheme ).…”

Section: Reactivity Studiesmentioning

confidence: 99%

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Metallaaromatic Chemistry: History and Development

2020

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Since the prediction of the existence of metallabenzenes in 1979, metallaaromatic chemistry has developed rapidly, due to its importance in both experimental and theoretical fields. Now six major types of metallaromatic compounds, metallabenzenes, metallabenzynes, heterometallaaromatics, dianion metalloles, metallapentalenes and metallapentalynes (also termed carbolongs), and spiro metalloles, have been reported and extensively studied. Their parent organic analogues may be aromatic, non-aromatic, or even anti-aromatic. These unique systems not only enrich the large family of aromatics, but they also broaden our understanding and extend the concept of aromaticity. This review provides a comprehensive overview of metallaaromatic chemistry. We have focused on not only the six major classes of metallaaromatics, including the main-group-metal-based metallaaromatics, but also other types, such as metallacyclobutadienes and metallacyclopropenes. The structures, synthetic methods, and reactivities are described, their applications are covered, and the challenges and future prospects of the area are discussed. The criteria commonly used to judge the aromaticity of metallaaromatics are presented.

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