The molecular dynamics and reactivity of tris(inden-1-yl)silane: an NMR spectroscopic and X-ray crystallographic study †

Stradiotto, Mark; Brook, Michael A.; McGlinchey, Michael J.

doi:10.1039/b000458h

Cited by 9 publications

(8 citation statements)

References 25 publications

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“…Congestion at the quaternary C(1) center in 22 results in an elongated C(1)-silicon bond (C(1)-Si(1) ) 1.938(7) Å) relative to tris(1-indenyl)silane 33 33) ) 1.508(9) Å) and those found in the cycloadduct 19 (C-CH 3 ) 1.519(4), 1.505(4) Å), is not observed. Moreover, while the C 5 and C 6 rings in 19 deviate only modestly from planarity (0.0217 and 0.0128 Å, respectively), the plane defined by the allylic unit (C(1)sC(2)dC(3)) intersects the C 6 plane (C(3a), C(4), C(5), C(6), C(7), and C(7a)) at an angle of approximately 3.2°, possibly due to unfavorable steric interactions between the C(1)-methyl group and the chromium fragment.…”

Section: Resultsmentioning

confidence: 99%

Probing the Effect of Organic and Organometallic Functionalization on [1,5]-Silicon Shifts in Indenylsilanes

et al. 2000

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Indenylsilanes bearing organic and organometallic substituents have been prepared in order to probe the effect of substitution on the rate of [1,5]-silicon shifts in this class of compounds. In an attempt to prepare 1,1,3-tris(trimethylsilyl)indene ( 7), the hitherto unknown silicon-functionalized bis(trimethylsilyl)dibenzo[a,d]fulvalene (9) was unexpectedly generated; this species was characterized by use of both NMR spectroscopy and X-ray crystallography and was rationally prepared in 68% yield from 3,3′-bis(1-(trimethylsilyl))indene ( 16). The molecular dynamics of 1,3-dimethyl-1-(trimethylsilyl)indene ( 18) and the crystallographically characterized chromium complex (η 6 -1,3-dimethyl-1-exo-(trimethylsilyl)indene)tricarbonylchromium ( 22) were examined by use of 1D-selective inversion and 2D-EXSY NMR techniques; surprisingly, the presence of chromium and methyl substituents has a negligible effect on the rate of [1,5]-silicon shifts (∆G q ) 23-24 kcal mol -1 ) versus the parent compound 1-(trimethylsilyl)indene (3) (∆G q ≈ 24 kcal mol -1 ). In the case of 18, the intermediate isoindene 18-iso was intercepted with tetracyanoethylene as the crystallographically characterized [4 + 2] cycloadduct 5,6-benzo-2,2,3,3-tetracyano-1,4-dimethyl-7-(trimethylsilyl)bicyclo(2.2.1)hept-5-ene (19).

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Section: Resultsmentioning

confidence: 99%

Probing the Effect of Organic and Organometallic Functionalization on [1,5]-Silicon Shifts in Indenylsilanes

et al. 2000

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“…The full gamut of two-dimensional 1 H, 13 C and 29 Si NMR data revealed the unequivocal assignment of the proton, carbon-13 and silicon-29 nuclei in all of the different indenyl ring environments and ultimately allowed the elucidation of their molecular dynamics [9]. As depicted in Scheme 6, the exchange pathways between indenyl sites in 11 can be mapped onto a cube (for the eight different indenyl ring environments), and a hypercube (for the exchange of 1 H in sp 2 and sp 3 environments) and again involve successive [1,5]-suprafacial sigmatropic shifts via isoindene intermediates; gratifyingly, several triple Diels-Alder TCNE adducts, 12, have been isolated and fully characterised by X-ray crystallography (Scheme 7) [16,17]. The full gamut of two-dimensional 1 H, 13 C and 29 Si NMR data revealed the unequivocal assignment of the proton, carbon-13 and silicon-29 nuclei in all of the different indenyl ring environments and ultimately allowed the elucidation of their molecular dynamics [9].…”

Section: Simentioning

confidence: 99%

The Effect of Benzannulation on the Structures, Reactivity and Molecular Dynamics of Indenes, Pentalenes, Azulenes and Related Molecules

McGlinchey

2022

Molecules

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The stabilising effect of benzannulation on isoindenes formed in the course of sigmatropic shifts of (C5H5)Fe(CO)2 or of organo-silyl groups, and on exocyclic allyl intermediates in the course of haptotropic shifts of organometallic fragments over polycyclic skeletons (fluorene, cyclopenta[def]phenanthrene, syn and anti dibenzpentalenes) is exemplified. This approach led to the development of the first organometallic molecular brake. Benzyne cycloadditions to anthracenes to form triptycenes also led to unexpected or multiple adducts that were characterised by X-ray crystallography. Synthetic routes to the previously elusive benz[cd]azulene system are presented. Finally, the complete mechanism of the stepwise assembly of dispiro- and diindenyltetracenes from fluorenylallenes is presented, whereby every intermediate has been unambiguously structurally characterised.

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“…As depicted in Figure 3 , the exchange pathways between indenyl sites in 3 can be mapped onto a cube (for the eight different indenyl ring environments), and a hypercube (for the exchange of 1 H in sp 2 and sp 3 environments) and again involve successive [1,5]-suprafacial sigmatropic shifts via isoindene intermediates. Gratifyingly, several triple Diels-Alder TCNE adducts, 4 , have been isolated and fully characterized by X-ray crystallography [ 18 , 19 ].…”

Section: Diels-alder Trapping Of Isoindenesmentioning

confidence: 99%

Diels-Alder Additions as Mechanistic Probes–Interception of Silyl-Isoindenes: Organometallic Derivatives of Polyphenylated Cycloheptatrienes and Related Seven-Membered Rings

McGlinchey

2020

Molecules

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The intermediacy of short-lived isoindenes, generated in the course of metallotropic or silatropic shifts over the indene skeleton, can be shown by Diels-Alder trapping with tetracyanoethylene, leading to the complete elucidation of the dynamic behaviour of a series of polyindenylsilanes. Cyclopentadienones, bearing ferrocenyl and multiple phenyl or naphthyl substituents undergo [4 + 2] cycloadditions with diaryl acetylenes or triphenylcyclopropene to form the corresponding polyarylbenzenes or cycloheptatrienes. The heptaphenyltropylium cation, [C7Ph7+], was shown to adopt a nonplanar shallow boat conformation. In contrast, the attempted Diels-Alder reaction of tetracyclone and phenethynylfluorene yielded electroluminescent tetracenes. Finally, benzyne addition to 9-(2-indenyl)anthracene, and subsequent incorporation of a range of organometallic fragments, led to development of an organometallic molecular brake.

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The molecular dynamics and reactivity of tris(inden-1-yl)silane: an NMR spectroscopic and X-ray crystallographic study †

Cited by 9 publications

References 25 publications

Probing the Effect of Organic and Organometallic Functionalization on [1,5]-Silicon Shifts in Indenylsilanes

Probing the Effect of Organic and Organometallic Functionalization on [1,5]-Silicon Shifts in Indenylsilanes

The Effect of Benzannulation on the Structures, Reactivity and Molecular Dynamics of Indenes, Pentalenes, Azulenes and Related Molecules

Diels-Alder Additions as Mechanistic Probes–Interception of Silyl-Isoindenes: Organometallic Derivatives of Polyphenylated Cycloheptatrienes and Related Seven-Membered Rings

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