Metal-Promoted Oxidative π-Conjugation and Coupling of Substituted-Fulvalene-Type Ligands:  Synthesis and Crystal Structures of π-Conjugated C24H12(SiMe3)2 and the Dimer [C24H13(SiMe3)2]2

Malaba, Dennis; Tessier, Claire A.; Youngs, Wiley J.

doi:10.1021/om950954b

Cited by 6 publications

(3 citation statements)

References 24 publications

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“…The compound crystallizes from dichloromethane in space group P 2 1 / n ; the monoclinic cell unit contains four molecules of (Tbf) 2 along with 4 equiv of dichloromethane (Figure ). An extraordinarily long C−C single bond between C1−C30 (1.615(2) Å) is found, nearly identical to the corresponding C−C bond in a comparable compound described by Malaba and Youngs . A nearly perfect face-to-face π−π stacking of the C5/C24 and C31/C41 rings is observed (distance of the ring centers 3.422 Å) …”

Section: Resultssupporting

confidence: 71%

Tetrabenzo[a,c,g,i]fluorenyllithium and η⁵-Tetrabenzo[a,c,g,i]fluorenyltitanium Complexes

Haase¹,

Saak²,

Lützen³

et al. 2006

Organometallics

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Tetrabenzo[a,c,g,i]fluorene (Tbf-H, 4) was deprotonated with n-butyllithium, leading to ionic Tbf-LiLn complexes 5 and 6, consisting of well-separated cations (Li(THF)4 (5), Li(DME)3 (6)) and Tbf anions. Subsequent reactions with chlorotitanium alkoxides Cl x Ti(O i Pr)4 - x (x = 1, 3) and chlorotitanium phenoxides {ClTi(OR)3(THF)}2 (R = C6H5 (12), 4-MeC6H4 (13), 4- t BuC6H4 (14)) give a series of η5-tetrabenzo[a,c,g,i]fluorenyltitanium complexes (TbfTiCl2(O i Pr) (11) and TbfTi(OR)3 [R = i Pr (10), C6H5 (15), 4-MeC6H4 (16), 4- t BuC6H4 (17)]), which were characterized by NMR, MS, and IR measurements and X-ray crystallography. Additionally, the compounds' properties regarding the syndiospecific polymerization of styrene when activated with MAO were explored. The activities increase in the following order [kg sPS/(mol Ti × mol styrene × h]: 11 (1420) < 17 (3400) < 16 (3740) < 10 (6040) < 15 (6720).

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Section: Resultssupporting

confidence: 71%

Tetrabenzo[a,c,g,i]fluorenyllithium and η⁵-Tetrabenzo[a,c,g,i]fluorenyltitanium Complexes

Haase¹,

Saak²,

Lützen³

et al. 2006

Organometallics

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“…Warrener and co-workers report that, in addition to the well-known cycloaddition chemistry exhibited by molecules which contain the o -xylylene moiety, the dimerization of isoindenes via ene-type mechanisms can occur if a hydrogen atom is present at the C(2) position. − It is also noteworthy that dimeric compounds closely related to 9 have received recent attention in the literature. Olmstead and co-workers have discussed the unexpected isolation of 10 (Chart ) in their attempt to generate an ansa -titanocene, while Youngs et al , demonstrated that geometrically constrained bis(trimethylsilyl)dibenzo[ a , f ]fulvalenes, such as 11 , can be readily prepared via oxidative coupling using group 13 metal halides.…”

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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“…X-ray diffraction study revealed that the two N -piperidineethyl-functionalized indenyl ring is coupled through a CC bond with a distance of 1.371(4) Å, which is longer than the standard 1.34 Å expected for the CC bond in ethylene and other planar fulvalenes . The C(3)−C(3a) distance of 1.371(4) Å is also slightly longer than that of 1.359(10) Å found in the π-conjugated fulvalene C 24 H 12 (SiMe 3 ) 2 . It is readily apparent from the crystallographic analysis that the C−C bond lengths in the conjugated fulvalene moiety of 9 alternate between long and short, and there is a significant double-bond localization between (C1)−C(2), C(3)−C(3A), and C(2A)−C(1A) (Table ).…”

Section: Resultsmentioning

confidence: 77%

Coordination and Reactivity Diversity ofN-Piperidineethyl-Functionalized Indenyl Ligands: Synthesis, Structure, Theoretical Calculation, and Catalytic Activity of Organolanthanide Complexes with the Ligands

et al. 2007

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The interactions of N-piperidineethyl-functionalized indene compounds 1-R-3-C 5 H 10 NCH 2 CH 2 C 9 H 6 (R ) H-(1), Me 3 Si-( 2)) with lanthanide(III) amides [(Me 3 Si) 2 N] 3 Ln(µ-Cl)Li(THF) 3 (Ln ) Yb, Eu, Sm, Nd) were studied. The results indicated that the ligands and reductive potentials of Ln 3+ /Ln 2+ have an influence on the reaction patterns and the coordination mode of the indenyl ligands with the central metals. Reactions of [(Me 3 Si) 2 N] 3 Ln(µ-Cl)Li(THF) 3 (Ln ) Yb, Eu) with 2 equiv of corresponding indene compounds 1-R-3-C 5 H 10 NCH 2 CH 2 C 9 H 6 (R ) H-(1), Me 3 Si-(2)) produced organolanthanide(II) complexes [η 5 :η 1 -C 5 H 10 NCH 2 CH 2 C 9 H 6 ] 2 Ln II (Ln ) Yb (3), Eu (5)) and novel organolanthanide(II) complexes with general formula [η 4 :η 4), Eu ( 6)), and a new highly conjugated bis(N-piperidineethyl)dibenzofulvalene, (C 5 H 10 NCH 2 CH 2 C 9 H 5 ) 2 ( 9), was unexpectedly isolated as a byproduct in the preparation of 6, indicating the ligands' effects on the coordination and reactivity patterns. Theoretical calculations on ytterbium(II) complexes having indenyl ligands indicated that the indenyl hapticity depends on the strain, steric, and electronic effects. Treatment of lanthanide(III) amides [(Me 3 Si) 2 N] 3 Ln(µ-Cl)Li(THF) 3 (Ln ) Sm, Nd) with 2 equiv of C 5 H 10 NCH 2 CH 2 C 9 H 7 (1) afforded indenyl lanthanide(III) complexes with general formula [η 3 -C 5 H 10 NCH 2 CH 2 C 9 H 6 ] 2 Ln III [η 3 :η 1 -C 5 H 10 NCH 2 CH 2 C 9 H 6 ] (Ln ) Sm (7), Nd (8)). The shortest distances involving the nonbridging atoms of the C 5 portions of the indenyl groups indicated an allyl-like nature of the ligand-to-metal coordination. The interaction of [(Me 3 Si) 2 N] 3 Sm III (µ-Cl)Li-(THF) 3 with 2 equiv of 1-Me 3 Si-3-C 5 H 10 NCH 2 CH 2 C 9 H 6 (2) produced an unexpected bis(N-piperidineethyl)dibenzofulvalene (C 5 H 10 NCH 2 CH 2 C 9 H 5 ) 2 (9) and other unidentified solids, suggesting the ligands' influence on the reactivity patterns. All the compounds were fully characterized by spectroscopic methods and elemental analyses. The structures of compounds 4, 7, 8, and 9 were additionally determined by X-ray diffraction study. The catalytic activity of the organolanthanide complexes 3-8 on MMA polymerization was examined. It was found that the π-bonded tris(N-piperidineethylindenyl)lanthanide(III) complexes 7 and 8 exhibit unexpected good catalytic activity on MMA polymerization, and complex 7 also showed an unexpected high catalytic activity on ε-caprolactone polymerization. It was found that the catalytic activity of the complexes depended on the polymerization conditions. The solvents, temperatures, substituted groups, and lanthanide ionic radii effects on the catalytic activity of the complexes were examined.

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Metal-Promoted Oxidative π-Conjugation and Coupling of Substituted-Fulvalene-Type Ligands: Synthesis and Crystal Structures of π-Conjugated C₂₄H₁₂(SiMe₃)₂ and the Dimer [C₂₄H₁₃(SiMe₃)₂]₂

Cited by 6 publications

References 24 publications

Tetrabenzo[a,c,g,i]fluorenyllithium and η⁵-Tetrabenzo[a,c,g,i]fluorenyltitanium Complexes

Tetrabenzo[a,c,g,i]fluorenyllithium and η⁵-Tetrabenzo[a,c,g,i]fluorenyltitanium Complexes

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

Coordination and Reactivity Diversity ofN-Piperidineethyl-Functionalized Indenyl Ligands: Synthesis, Structure, Theoretical Calculation, and Catalytic Activity of Organolanthanide Complexes with the Ligands

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Metal-Promoted Oxidative π-Conjugation and Coupling of Substituted-Fulvalene-Type Ligands: Synthesis and Crystal Structures of π-Conjugated C24H12(SiMe3)2 and the Dimer [C24H13(SiMe3)2]2

Cited by 6 publications

References 24 publications

Tetrabenzo[a,c,g,i]fluorenyllithium and η5-Tetrabenzo[a,c,g,i]fluorenyltitanium Complexes

Tetrabenzo[a,c,g,i]fluorenyllithium and η5-Tetrabenzo[a,c,g,i]fluorenyltitanium Complexes

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

Coordination and Reactivity Diversity ofN-Piperidineethyl-Functionalized Indenyl Ligands: Synthesis, Structure, Theoretical Calculation, and Catalytic Activity of Organolanthanide Complexes with the Ligands

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Metal-Promoted Oxidative π-Conjugation and Coupling of Substituted-Fulvalene-Type Ligands: Synthesis and Crystal Structures of π-Conjugated C₂₄H₁₂(SiMe₃)₂ and the Dimer [C₂₄H₁₃(SiMe₃)₂]₂

Tetrabenzo[a,c,g,i]fluorenyllithium and η⁵-Tetrabenzo[a,c,g,i]fluorenyltitanium Complexes

Tetrabenzo[a,c,g,i]fluorenyllithium and η⁵-Tetrabenzo[a,c,g,i]fluorenyltitanium Complexes