2,3,4,5-Tetraphenylcyclopenta-2,4-dien-1-one and 5,6,7,8-tetrachloro-3a,9a-dihydro-2,3,3a,9a-tetraphenylcyclopenta[2,3-b][1,4]benzodioxin-1-one–toluene (2/1): compounds of photochemical interest

Barnes, John C.; Horspool, W. M.; Mackie, F. I.

doi:10.1107/s0108270190005145

Cited by 12 publications

(19 citation statements)

References 3 publications

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“…The solution slowly changed colour from orange to deep purple. Filtration and concentration of the reaction mixture produced dichroic purple/yellow crystals of tpc ( a =26.25, b =8.24, c =21.63, β =119.79, consistent with literature). The solution was concentrated, and then filtered repeatedly until crystals of tpc no longer formed.…”

Section: Methodssupporting

confidence: 88%

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Bulky Ytterbium Formamidinates Stabilise Complexes with Radical Ligands, and Related Samarium “Tetracyclone” Chemistry

Werner

Zhao

Best

et al. 2017

Chemistry A European J

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Divalent [Yb(DippForm) (thf) ] (n=2 (1 a), or 1 (1 b), DippForm=N,N'-bis(2,6-diisopropylphenyl)formamidinate) complexes were treated with the ketones: 9-fluorenone (fn), or 2,3,4,5-tetraphenylcyclopentadienone (tpc, tetracyclone), giving ketyl complexes: [Yb(DippForm) (fn -O)(thf)] (2), and [Yb(DippForm) (tpc -O)] (3), respectively (ketyl=a radical anion containing a C -O group. By contrast, when perfluorobenzophenone (pfb) was treated with either 1 a or 1 b, transitory ketyl formation was followed by rapid decomposition through a C-F activation pathway, giving [YbF(DippForm) (thf)] (4 a) and a highly unusual fluoride/oxide-bridged species: [Yb F O (DippForm) ] (4 b). The reduction of diketones: 3,5-di-tert-butyl-1,2-benzoquinone (tbbq), 9,10-phenanthrenequinone (phen), or 1,2-acenaphthenequinone (acen), was also examined giving ketyl complexes: [Yb(DippForm) (tbbq -O )] (5), [Yb(DippForm) (phen -O )] (6), and [Yb(DippForm) (acen -O )(thf)] (7). An unsolvated derivative of 7, namely [Yb(DippForm) (acen -O )] (8), was obtained from PhMe. All ketyl complexes had suitably elongated C -O bonds, were stable in both polar and non-polar solvents-an uncommon trait for rare-earth ketyl complexes-and, with the exception of 3, showed radical signals in ESR spectra. To investigate the reactivity of the tpc -O ketyl complex, 3 was treated with oxidants (CS , Se) and reducing agents (Mg , KH, or [SmI (thf) ]). Thus 3 was oxidised to tpc by Se. Treatment of 3 with KH led to a ligand exchange process giving an unusual diketyl species [Yb(DippForm)(tpc -O) (thf) ] (10), which has two cisoid tpc -O ligands in very close proximity. When treated with [SmI (thf) ], the tpc -O ketyl was further reduced to a dianion (1-oxido-2,3,4,5-tetraphenylcyclopentadianide ), ({C Ph }-O) by [SmI (thf) ], giving dimeric [{SmI({C Ph }-O)(thf) } ] (Sm11) and monomeric complexes [YbI(DippForm) (thf)] (11 b) and [YbI (DippForm)(thf) ] (11 c). Activated Sm metal reduced neutral tetracyclone to the dianion, ({C Ph }-O) , in THF, giving tetranuclear [{Sm ({C Ph }-O) (thf) } ] (Sm13). Treatment of Sm13 with iodine in situ provided access to [{SmI({C Ph }-O)(thf) } ] (Sm11), in good yield.

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Section: Methodssupporting

confidence: 88%

“…‐ O ketyl in 2⋅ THF, namely, a short Yb−O bond, and an elongated C−O bond (1.313(6) Å, cf. C−O in tpc=1.208 Å) . Intriguingly, the tpc .…”

Section: Resultsmentioning

confidence: 90%

Bulky Ytterbium Formamidinates Stabilise Complexes with Radical Ligands, and Related Samarium “Tetracyclone” Chemistry

Werner

Zhao

Best

et al. 2017

Chemistry A European J

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show abstract

“…For a better understanding of the prerequisites of the two classes of compounds, it is worthwhile to note their differing structural features. The cyclopentadienone unit in the tetracyclones is planar [34], whereas thiophene-Soxides are puckered, and the lone electron pair on sulfur interacts less with the diene system, as can be observed from crystal structural data [35]. Pi-Bond conjugation and electron density distribution differ in the two classes of molecules.…”

Section: Introductionmentioning

confidence: 82%

Electrochemical oxidation of tetracyclones and tetraphenylthiophene-S-oxide

Iniesta

Alcock

Walton

et al. 2006

Electrochimica Acta

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“…Bond distances and angles within the phenyl rings are mostly unexceptional (Barnes et al, 1991) and each individual ring is planar (out-of-plane displacements being less than 0.02A). It is noteworthy, however, that the internal angles about the substituted C atoms of the phenyl groups are consistently less than 120 ° [ranging from 118.20(16) to 118.69 (16)°; Table 2].…”

Section: Commentmentioning

confidence: 99%

“…Instead, compound (1) assumes a four-bladed propeller-like structure with the blades alternately above and below the central ring. The dihedral angles of the four phenyl substituents with the central five-membered ring of (1) are 35.3 (2), 47.3 (4), 61.1(3) and 28.0(2)" (Barnes, Horspool & Mackie, 1991).…”

Section: Commentmentioning

confidence: 99%