Electrochemically Informed Synthesis: Oxidation versus Coordination of 5,6‐Bis(phenylchalcogeno)acenaphthenes

Knight, Fergus R.; Randall, Rebecca A. M.; Roemmele, Tracey L.; Boeré, René T.; Bode, Bela E.; Crawford, Luke; Bühl, Michæl; Slawin, Alexandra M. Z.; Woollins, J. Derek

doi:10.1002/cphc.201300678

Cited by 11 publications

(27 citation statements)

References 96 publications

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“…From this, we conclude that ( 5b -H) • is somewhat stabilized by the peri-backbone. In fact, peri-substitution has previously been used to stabilize several radical species for this reason, including boryl and chalcogen − radicals.…”

Section: Resultsmentioning

confidence: 99%

“…The work of our group has focused on peri-substitution, which is a double substitution in the 1,8 positions of naphthalene or the 5,6 positions of acenaphthene . The rigid scaffold and enforced proximity this provides is useful in thermodynamically stabilizing bonding motifs which are typically unstable at room temperature, such as subvalent or redox metastable species. − Other groups have used peri-substitution to stabilize free radicals − and to generate strong Lewis acids for frustrated Lewis pair chemistry. − …”

Section: Introductionmentioning

confidence: 99%

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Dealkanative Main Group Couplings across the peri-Gap

et al. 2017

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Here, we highlight the ability of peri-substitution chemistry to promote a series of unique P-P/P-As coupling reactions, which proceed with concomitant C-H bond formation. This dealkanative reactivity represents an interesting and unexpected expansion to the established family of main-group dehydrocoupling reactions. These transformations are exceptionally clean, proceeding essentially quantitatively at relatively low temperatures (70-140 °C), with 100% diastereoselectivity in the products. The reaction appears to be radical in nature, with the addition of small quantities of a radical initiator (azobis(isobutyronitrile)) increasing the rate dramatically, as well as altering the apparent order of reaction. DFT calculations suggest that the reaction involves dissociation of a phosphorus centered radical (stabilized by the peri-backbone) to the P-P coupled product and a free propyl radical, which carries the chain. This unusual reaction demonstrates the powerful effect that geometric constraints, in this case a rigid scaffold, can have on the reactivity of main group species, an area of research that is gaining increasing prominence in recent years.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dealkanative Main Group Couplings across the peri-Gap

et al. 2017

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“…[17,18] The ease of synthesising the valuable precursor 5,6-dibromoacenaphthene [20] compared to the more laborious method for preparing the naphthalene equivalent, [21] has seen an increasing rise in the use of the acenaphthene scaffold for preparing peri-substituted species. [22][23][24][25][26][27] The related acenaphthylene backbone incorporating a C=C double bond on the bridging moiety, however, has seen limited use. Herein, we report the synthesis and structural characterisation of a series of halogen and chalcogen peri-substituted acenaphthylenes 1-12, analogues of previously reported naphthalenes N1-N12 [18] and acenaphthenes A1-A12, [17] along with 5,6-dihaloacenaphthylenes 13 (Br) [28,29] and 14 (I).…”

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confidence: 99%

Bridging the Gap: Attractive 3c–4e Interactions in peri‐Substituted Acenaphthylenes

et al. 2014

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Keywords: acenaphthylene /peri-substitution /3c-4e interaction /X-ray crystallography / DFT calculations/non-covalent A series of peri-substituted acenaphthylenes containing mixed halogen-chalcogen functionalities at the 5,6-positions in 1-6 (Acenapyl [X][EPh] (Acenap = acenaphthylene-5,6-diyl; X = Br, I; E = S, Se, Te) and chalcogen-chalcogen moieties in 7-11 (Acenap [EPh][E`Ph] (Acenap = acenaphthene-5,6-diyl; E/E` = S, Se, Te), have been prepared from their corresponding acenaphthene analogues A1-A11, utilizing 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) for the dehydrogenation of the ethane backbone. The related dihalide compounds 13 and 14 Acenapyl[XX`] (XX` = BrBr, II) have also been prepared following a similar procedure and 1,2,5,6-tetrabromo-1,2-dihydroacenaphthylene A0 was prepared as an intermediate following an alternative route to 13. The series of acenaphthylene compounds have remarkably similar molecular structures to their acenaphthene counterparts, exhibiting an expected increase in periseparation as heavier congeners occupy the close peri-positions.The presence of the ethene bridge, however, naturally compresses the nearest bay angle whilst increasing the splay of the exocyclic peri-atoms, resulting in a minor increase in separation compared with equivalent acenaphthenes. The structures of 1-11, 13 and 14 are discussed and compared with previously reported analogous naphthalene and acenaphthene compounds. Similar to acenaphthene derivatives, aromatic ring conformations and the location of p-type lone-pairs influences the geometry of the peri-region. Under appropriate geometric conditions quasi-linear three-body C Ph -E···Z (E = Te, Se, S; Z = Br/E) fragments provide an attractive component for the E···Z interaction. DFT studies confirm the onset of formation of threecenter, four-electron bonding, similar in extent as observed in analogous acenaphthenes, despite an increase in the peridistances. IntroductionUnderstanding how atoms interact in different bonding situations and the ability to quantify the extent of bonding between two atoms is an ongoing challenge for chemists, and one which dates back to the origins of the electronic theory of valence proposed by Lewis and Langmuir in the early 1900s. [1,2] The stability of molecules was originally ascribed to their ability to pair valence electrons off in chemical bonds to achieve 'stable octets', with the concept of covalence introduced as 'the number of pairs of electrons an atom can share with its neighbor'. [1][2][3] Ambiguity over the bonding in molecules of heavier main-block elements (period 3 and higher), in which an 'octet expansion' would be required in order to conform to conventional Lewis 2c-2e covalent bonding theory, was thus rationalized by the availability of unfilled low-lying d-orbitals. [1] Langmuir, however, accounted for the legitimacy of the octet rule by suggesting the bonding in these species, termed hypervalent, [4] was now ionic rather than covalent in nature. [2] The advancement of molecular orbital theory in t...

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“…2). 19 The positive ion ESI MS spectrum of 3 •+ exhibits a molecular ion peak with the correct isotropic distribution pattern ([M + 3H] + = 445). In the IR spectrum the FBF deformation vibration is visible as a very strong signal at δ as (FBF) = 1057 and the BF 4 stretch vibration is visible as a medium signal at ν as (BF 4 ) = 528 which goes hand in hand with reported signals in the literature of the [Co(NH 3 ) 6 ](BF 4 ) 2 complex and NaBF 4 .…”

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Diphosphane 2,2′-binaphtho[1,8-de][1,3,2]dithiaphosphinine and the easy formation of a stable phosphorus radical cation

et al. 2016

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Electrochemically Informed Synthesis: Oxidation versus Coordination of 5,6‐Bis(phenylchalcogeno)acenaphthenes

Abstract: Chalcogen dications: Facile synthesis of EE bonded dications can be readily achieved. Radical cations are identified as the intermediates.

Cited by 11 publications

References 96 publications

Dealkanative Main Group Couplings across the peri-Gap

Dealkanative Main Group Couplings across the peri-Gap

Bridging the Gap: Attractive 3c–4e Interactions in peri‐Substituted Acenaphthylenes

Diphosphane 2,2′-binaphtho[1,8-de][1,3,2]dithiaphosphinine and the easy formation of a stable phosphorus radical cation

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