Brücken zwischen Anorganischer und Organischer Chemie (Nobel‐Vortrag)

Hoffmann, Roald

doi:10.1002/ange.19820941002

Cited by 435 publications

(7 citation statements)

References 110 publications

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“…Formal replacement of the [Si(Idipp)] fragments in [(Idipp)(R)Si II Si 0 (Idipp)] + ( 1R + , R = H, Me, Et) by the isolobal fragments [SiR] − and [PR] , leads to a series of Si and P multiple-bonded compounds B – F , which are depicted in Scheme . Class B , C and F compounds are very rare, whereas disilenide anions ( D ) ,, and phosphasilenes ( E ) are familiar classes of compounds, the synthetic potential of which has been exploited.…”

Section: Resultsmentioning

confidence: 99%

“…An alternative view of 1 was recently presented in an experimental and theoretical study by our group, which uncovered the similarity of the electronic structure of 1 with that of the diphosphene ( E )-Mes*PPMes* (Mes* = C 6 H 2 -2,4,6- t Bu 3 ) and the NHC-stabilized phosphasilenylidene (Idipp)SiPMes*, with all three compounds showing a similar sequence of the frontier orbitals with almost isoenergetic n + (E–E) lone pair (E = Si or P) and π(EE) orbitals as the HOMO and the HOMO–1, respectively . This relationship, which can be traced back to the isolobal analogy of the fragments [Si(NHC)], [PR] and [SiR] − , allowed also to rationalize the experimentally determined structure of the 1e-oxidation product of 1 ([Si 2 (Idipp) 2 ] + ), and to interrelate its electronic structure with that of the disilyne radical anions [Si 2 R 2 ] − . , …”

Section: Introductionmentioning

confidence: 95%

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Addition of Small Electrophiles to N-Heterocyclic-Carbene-Stabilized Disilicon(0): A Revisit of the Isolobal Concept in Low-Valent Silicon Chemistry

et al. 2016

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Protonation and alkylation of (Idipp)Si═Si(Idipp) (1) afforded the mixed-valent disilicon(I)-borates [(Idipp)(R)Si(II)═Si(0)(Idipp)][B(Ar(F))4] (1R[B(Ar(F))4]; R = H, Me, Et; Ar(F) = C6H3-3,5-(CF3)2; Idipp = C[N(C6H3-2,6-iPr2)CH]2) as red to orange colored, highly air-sensitive solids, which were characterized by single-crystal X-ray diffraction, IR spectroscopy and multinuclear NMR spectroscopy. Dynamic NMR studies in solution revealed a degenerate isomerization (topomerization) of the "σ-bonded" tautomers of 1H[B(Ar(F))4], which proceeds according to quantum chemical calculations via a NHC-stabilized (NHC = N-heterocyclic carbene) disilahydronium ion ("π-bonded" isomer) and is reminiscent of the degenerate rearrangement of carbenium ions formed upon protonation of olefins. The topomerization of 1H[B(Ar(F))4] provides the first example of a reversible 1,2-H migration along a Si═Si bond observed in a molecular system. In contrast, 1Me[B(Ar(F))4] adopts a "rigid" structure in solution due to the higher energy required for the interconversion of the "σ-bonded" isomer into a putative NHC-stabilized disilamethonium ion. Addition of alkali metal borates to 1 afforded the alkali metal disilicon(0) borates 1M[BAr4] (M = Li, Ar = C6F5; M = Na, Ar = Ar(F)) as brown, air-sensitive solids. Single-crystal X-ray diffraction analyses and NMR spectroscopic studies of 1M[BAr4] suggest in concert with quantum chemical calculations that encapsulation of the alkali metal cations in the cavity of 1 predominantly occurs via electrostatic cation-π interactions with the Si═Si π-bond and the peripheral NHC aryl rings. Displacement of the [Si(NHC)] fragments by the isolobal fragments [PR] and [SiR](-) interrelates the cations [(NHC)(R)Si═Si(NHC)](+) to a series of familiar, multiply bonded Si and P compounds as verified by analyses of their electronic structures.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Addition of Small Electrophiles to N-Heterocyclic-Carbene-Stabilized Disilicon(0): A Revisit of the Isolobal Concept in Low-Valent Silicon Chemistry

et al. 2016

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“…[Ph 3 PAuCl] is transformed during the reaction via a salt metathesis into the [Ph 3 PAu] + cation. Because [Ph 3 PAu] + is isolobal to H + , compound 2 can be considered as being isolobal to CH 2 (PPh 2 NSiMe 3 ) 2 2 Perspective ORTEP view of the molecular structure of 2 .…”

Section: Resultsmentioning

confidence: 99%

Reactions of Potassium Bis(phosphinimino)methanide with Group 11 Compounds

et al. 2006

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Transmetalation of the potassium methanide complex, K{CH(PPh2NSiMe3)2}, with [(Ph3P)2CuI] afforded the corresponding copper complex [{CH(PPh2NSiMe3)2}CuPPh3] (1), whereas the reaction of K{CH(PPh2NSiMe3)2} with [Ph3PAuCl] resulted in the dinuclear gold complex [(Ph3PAu)2{C(PPh2NSiMe3)2}] (2). The solid-state structure of 1 shows the formation of a six-membered metallacycle (N1-P1-C1-P2-N2-Cu) that has a twist boat conformation. In contrast, compound 2 is an alpha,alpha-diaurated species, in which the two gold atoms are coordinated in a linear fashion onto the ligand backbone. Photoluminescence measurements show that the latter compound has a strong violet emission.

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“…55 74 is an isolobal equivalent of 46 where the RC fragment is replaced by a P atom. 71 The Si 2 P 2 four-membered ring is planar and consists of four Si-P bonds which are equal in lengths (2.174 A) (Fig. 8).…”

Section: Reactivity Of Functionalized Silylenesmentioning

confidence: 99%

Chemistry of functionalized silylenes

et al. 2012

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Recent years have witnessed important developments in organosilicon chemistry, courtesy to the high yield access of stable monomeric chlorosilylene (LSiCl, L ¼ PhC(NtBu) 2 ) and N-heterocyclic carbene (NHC) stabilized dichlorosilylene (L 1 SiCl 2 , L 1 ¼ 1,3-bis(2,6-iPr 2 C 6 H 3 )imidazol-2-ylidene) by dehydrochlorination technique using strong bases such as N-heterocyclic carbenes or LiN(SiMe 3 ) 2 as HCl scavenger. The chemistry of functionalized silylenes is markedly different from the previously reported dicoordinate silylenes. Their utility as synthons is well documented which paves the way for several striking compounds, e.g. monosilaoxiranes, CSi 2 P derivative, CSi 3 P cation, a dimer of silaisonitrile (Si 2 N 2 ) with dicoordinate Si atoms etc. This study also unravels that these functionalized silylenes are proficient at activating phosphorus, and the functional group attached to the a-position of the silicon(II) centre plays a key role to determine the final product. The reaction of P 4 with LSiCl affords a zwitterionic Si 2 P 2 ring, while with LSiN(SiMe 3 ) 2 it gives an acyclic Si 2 P 4 derivative. Another recent achievement in this field is the successful isolation of a valence isomer of disilyne known as the inter-connected bis-silylene. This perspective portrays the chemistry of functionalized silylenes which will attract great attention, heading for the further development of organosilicon chemistry.

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Brücken zwischen Anorganischer und Organischer Chemie (Nobel‐Vortrag)

Cited by 435 publications

References 110 publications

Addition of Small Electrophiles to N-Heterocyclic-Carbene-Stabilized Disilicon(0): A Revisit of the Isolobal Concept in Low-Valent Silicon Chemistry

Addition of Small Electrophiles to N-Heterocyclic-Carbene-Stabilized Disilicon(0): A Revisit of the Isolobal Concept in Low-Valent Silicon Chemistry

Reactions of Potassium Bis(phosphinimino)methanide with Group 11 Compounds

Chemistry of functionalized silylenes

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