Multiply substituted cyclopentadienyl metal complexes: I. Solid-state and solution conformational studies on

Plooy, Karen E. du; Toit, Johan Du; Levendis, Demetrius C.; Coville, Neil J.

doi:10.1016/0022-328x(95)05865-m

Cited by 10 publications

(6 citation statements)

References 46 publications

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“…Synthesis of [Zn(C 5 Me 4 t Bu)) 2 ] (3), [Zn(C 5 Me 4 SiMe 2 t Bu) 2 ] (4) and [Zn(C 5 Me 4 SiMe 3 ) 2 ] (5): These compounds were prepared by reaction of ZnCl 2 and MCp′ in THF, at room temperature, for a period of about 3 h (M=K, Cp′=C 5 Me 4 t Bu for 3 ;53 M=Li, Cp′=C 5 Me 4 SiMe 2 t Bu for 4 ;54 M=K, Cp′=C 5 Me 4 SiMe 3 for 5 ;52b). After removal of the volatiles in vacuo the residue was dissolved in hexane and the solutions filtered.…”

Section: Methodsmentioning

confidence: 99%

Structural Analysis of Zincocenes with Substituted Cyclopentadienyl Rings

Fernández

Grirrane

Resa

et al. 2009

Chemistry A European J

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New zincocenes [ZnCp'(2)] (2-5) with substituted cyclopentadienyl ligands C(5)Me(4)H, C(5)Me(4)tBu, C(5)Me(4)SiMe(2)tBu and C(5)Me(4)SiMe(3), respectively, have been prepared by the reaction of ZnCl(2) with the appropriate Cp'-transfer reagent. For a comparative structural study, the known [Zn(C(5)H(4)SiMe(3))(2)] (1), has also been investigated, along with the mixed-ring zincocenes [Zn(C(5)Me(5))(C(5)Me(4)SiMe(3))] (6) and [Zn(C(5)Me(5))(C(5)H(4)SiMe(3))] (7), the last two obtained by conproportionation of [Zn(C(5)Me(5))(2)] with 5 or 1, as appropriate. All new compounds were characterised by NMR spectroscopy, and by X-ray methods, with the exception of 7, which yields a side-product (C) upon attempted crystallisation. Compounds 5 and 6 were also investigated by (13)C CPMAS NMR spectroscopy. Zincocenes 1 and 2 have infinite chain structures with bridging Cp' ligands, while 3 and 4 exhibit slipped-sandwich geometries. Compounds 5 and 6 have rigid, eta(5)/eta(1)(sigma) structures, in which the monohapto C(5)Me(4)SiMe(3) ligand is bound to zinc through the silyl-bearing carbon atom, forming a Zn--C bond of comparable strength to the Zn--Me bond in ZnMe(2). Zincocene 5 has dynamic behaviour in solution, but a rigid eta(5)/eta(1)(sigma) structure in the solid state, as revealed by (13)C CPMAS NMR studies, whereas for 6 the different nature of the Cp' ligands and of the ring substituents of the eta(1)-Cp' group (Me and SiMe(3)) have permitted observation for the first time of the rigid eta(5)/eta(1) solution structure. Iminoacyl compounds of composition [Zn(eta(5)-C(5)Me(4)R)(eta(1)-C(NXyl)C(5)Me(4)R)] resulting from the reactions of some of the above zincocenes and CNXyl (Xyl=2,6-dimethylphenylisocyanide) have also been obtained and characterised.

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Section: Methodsmentioning

confidence: 99%

Structural Analysis of Zincocenes with Substituted Cyclopentadienyl Rings

Fernández

Grirrane

Resa

et al. 2009

Chemistry A European J

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“…Fe(CO) 5 was used as supplied from Aldrich chemicals. Compound 2 , (C 5 Me 5 )Fe(CO) 2 I, (C 5 Me 4 H)Fe(CO) 2 I, 1 and C 5 Me 4 H 2 were all prepared according to literature methods.…”

Section: Methodsmentioning

confidence: 99%

Steric Limit of cis-[(C₅R₅)Fe(CO)₂]₂ Complexes in Solution

1997

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The symmetrical dimers [(C 5 H 5 )Fe(CO) 2 ] 2 (1), [(C 5 Me 5 )Fe(CO) 2 ] 2 (2), and [(C 5 Me 4 H)Fe(CO) 2 ] 2 (3) have been used to synthesize the unsymmetrical dimers (C 5 -Me 4 H)(C 5 H 5 )Fe 2 (CO) 4 (4), (C 5 Me 5 )(C 5 H 5 )Fe 2 (CO) 4 (5), and (C 5 Me 5 )(C 5 Me 4 H)Fe 2 (CO) 4 (6). All of the new compounds show cis/trans isomerization to varying extents, depending on the degree of substitution. The crystal structures of 3 and 4 have been determined. The limit of the observable cis-bridged isomer is found in 6 which is 14% cis in CH 3 CN solution.

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“…Dehydrated solvent was used in the reaction. HCp *Ethyl (5-ethyl-1,2,3,4-tetramethylcyclopentadiene) [65], HCp *iPr (5-isopropyl-1,2,3,4-tetramethylcyclopentadiene) [64,65], HCp *tBu (5-tert-butyl-1,2,3,4tetramethylcyclopentadiene) [66], (Cp*Ir(6,6'-dihydroxy-2,2'-bipyridine)Cl)Cl (2b) [ [a] Conversion and yields were determined by GC using biphenyl as internal standard.…”

Section: Generalmentioning

confidence: 99%

“…Dehydrated solvent was used in the reaction. HCp *Ethyl (5-ethyl-1,2,3,4-tetramethylcyclopentadiene) [65], HCp *iPr (5-isopropyl-1,2,3,4tetramethylcyclopentadiene) [64,65], HCp *tBu (5-tert-butyl-1,2,3,4-tetramethylcyclopentadiene) [66], (Cp*Ir(6,6 -dihydroxy-2,2 -bipyridine)Cl)Cl (2b) [67], Cp*Ir(2.2 -bipyridine-6,6 -dionato)H 2 O (3b) [40], and 6,6 -dihydroxy-2,2 -bipyridine [68] were prepared according to the literature method. All other reagents are commercially available and were used as received (FUJIFILM Wako Pure Chemical Corp., Osaka, Japan); (Nacalai Tesque, Kyoto, Japan); (Tokyo Chemical Industry Co., Ltd., Tokyo, Japan).…”

Section: Generalmentioning

confidence: 99%

“…Under an atmosphere of argon, IrCl 3 ·5H 2 O (546.5 mg, 1.41 mmol) was placed in a 50-mL two-neck flask equipped with a Dimroth condenser and three-way cock. Methanol (11.1 mL) and 5-tert-butyl-1,2,3,4-tetramethylcyclopentadiene [66] (1010.0 mg, 5.66 mmol) were added, and the mixture was stirred for 144 h at 90 • C. After cooling to r.t., orange precipitate was filtered with a glass filter, washed with Et 2 O (10 mL), and then dried under vacuum to give an orange solid (276. 8 Under an atmosphere of argon, (Cp* tBu IrCl 2 ) 2 (1e) (36.3 mg, 0.04 mmol), 6,6 -dihydroxy-2,2bipyridine (15.7 mg, 0.08 mmol), and methanol (0.7 mL) were placed in a 10-mL two-neck test tube flask equipped with a Dimroth condenser and three-way cock.…”

Section: Generalmentioning

confidence: 99%

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Effect of a Substituent in Cyclopentadienyl Ligand on Iridium-Catalyzed Acceptorless Dehydrogenation of Alcohols and 2-Methyl-1,2,3,4-tetrahydroquinoline

Jeong¹,

Shimbayashi²,

Fujita³

2019

Catalysts

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New iridium(III)-bipyridonate complexes having cyclopentadienyl ligands with a series of alkyl substituents were synthesized for the purpose of tuning the catalytic activity for acceptorless dehydrogenation reactions. A comparison of the catalytic activity was performed for the reaction of alcoholic substrates such as 1-phenylethanol, 2-octanol, and benzyl alcohol. The 1-t-butyl-2,3,4,5-tetramethylcyclopentadienyl iridium complex exhibited the best performance, which surpassed that of the 1,2,3,4,5-pentamethylcyclopentadienyl (Cp*) iridium catalyst in the dehydrogenation reaction of alcohols. The catalytic activity in the dehydrogenation of 2-methyl-1,2,3,4-tetrahydroquinoline was also examined. The highest efficiency was obtained in the reaction catalyzed by the same t-butyl-substituted cyclopentadienyl iridium complex.

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Multiply substituted cyclopentadienyl metal complexes: I. Solid-state and solution conformational studies on

Cited by 10 publications

References 46 publications

Structural Analysis of Zincocenes with Substituted Cyclopentadienyl Rings

Structural Analysis of Zincocenes with Substituted Cyclopentadienyl Rings

Steric Limit of cis-[(C₅R₅)Fe(CO)₂]₂ Complexes in Solution

Effect of a Substituent in Cyclopentadienyl Ligand on Iridium-Catalyzed Acceptorless Dehydrogenation of Alcohols and 2-Methyl-1,2,3,4-tetrahydroquinoline

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Multiply substituted cyclopentadienyl metal complexes: I. Solid-state and solution conformational studies on

Cited by 10 publications

References 46 publications

Structural Analysis of Zincocenes with Substituted Cyclopentadienyl Rings

Structural Analysis of Zincocenes with Substituted Cyclopentadienyl Rings

Steric Limit of cis-[(C5R5)Fe(CO)2]2 Complexes in Solution

Effect of a Substituent in Cyclopentadienyl Ligand on Iridium-Catalyzed Acceptorless Dehydrogenation of Alcohols and 2-Methyl-1,2,3,4-tetrahydroquinoline

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Steric Limit of cis-[(C₅R₅)Fe(CO)₂]₂ Complexes in Solution