Synthesis, Characterization, and Polymerization Properties of Bis(2-menthylindenyl)zirconium Dichloride and Bis(2-menthyl-4,7-dimethylindenyl)zirconium Dichloride

Abstract

The tetrakis(triphenylphosphine)palladium-catalyzed cross coupling of 2-bromoindene or 2-bromo-4,7-dimethylindene with menthylmagnesium chloride gave the novel ligands 2-menthylindene (10) and 2-menthyl-4,7-dimethylindene (11) in 66 and 57% yields. These indenes were deprotonated with n-BuLi to give isolated indenyllithium complexes which were metalated with zirconium tetrachloride to give bis(2-menthylindenyl)zirconium dichloride ( 14) and bis(2-menthyl-4,7-dimethylindenyl)zirconium dichloride (15) in 40 and 66% yields. Both complexes formed as their single possible stereoisomer and were characterized by X-ray crystallography and MS, NMR, and IR spectroscopy. The variable-temperature 1 H NMR spectrum of bis(2-menthyl-4,7-dimethylindenyl)zirconium dichloride (15) showed that it interconverts with a rotational activation barrier of about 12.5 ( 0.5 kcal/mol, and that a 60:40 mixture of C 2 -symmetric diastereomeric conformations was present at -50 °C. The 1 H NMR spectrum of bis(2-menthylindenyl)zirconium dichloride ( 14) was invariant between -50 and +50 °C. Complexes 14 and 15 polymerized propene in the presence of methylaluminumoxane (MAO) and hydrogen (10 960 and 33 750 g PP/g Zr h, respectively). The molecular weights and stereoregularity of the polymers produced were low.

Chiral Indenes and Group‐4 Metallocene Dichlorides Containing α‐ and β‐Pinenyl‐Derived Ligand Substituents: Synthesis and Catalytic Applications in Polymerization and Carboalumination Reactions

“…C in six-membered ring or in pinenyl ring), 26.06 (aliph. C in six-membered ring or in pinenyl ring), 25.68 (aliph. C in six-membered ring or in pinenyl ring), 25.61 (aliph.…”

“…When to this mixture was added cold pentane at -60°C a small sample (0.054 g, 3 %) of 8a/8b was obtained as yellow crystals enriched in one of the racemic-like diastereomers in a 57:43 ratio. CH in 8a and 8b), 106.70 (4 olefinic CH in five-membered ring in 8a and 8b), 48.82 (2 CH in pinenyl ring in 8a and 8b), 48.79 (2 CH in pinenyl ring in 8a and 8b), 40.71 (2 CH in pinenyl ring in 8a and 8b), 40.67 (2 CH in pinenyl ring in 8a and 8b), 39.45 (4 C q in pinenyl ring in 8a and 8b), 30.96 (2 CH in pinenyl ring in 8a and 8b), 30.87 (2 CH in pinenyl ring in 8a and 8b), 26.89 (2 CH 3 attached to pinenyl ring in 8a or 8b), 26.83 (2 CH 3 attached to pinenyl ring in 8a or 8b), 25.86 (2 CH in pinenyl ring in 8a and 8b), 25.80 (2 CH in pinenyl ring in 8a and 8b), 25.05 (2 bridging CH 2 between pinenyl ring and Si in 8a or 8b), 24.96 (2 bridging CH 2 between pinenyl ring and Si in 8a or 8b), 24.86 (4 CH in pinenyl ring in 8a and 8b), 22.95 (2 CH in pinenyl ring in 8a and 8b), 22.92 (2 CH in pinenyl ring in 8a and 8b), 20.00 (2 CH 3 attached to pinenyl ring in 8a or 8b), 19.95 (2 CH 3 attached to pinenyl ring in 8a or 8b), 13.83 (2 CH 3 attached to five-membered ring in 8a or 8b), 13.80 (2 CH 3 attached to five-membered ring in 8a or 8b), -0.52 (2 CH 3 attached to Si in 8a or 8b), -0.86 (2 CH 3 attached to Si in 8a or 8b), -1.03 (2 CH 3 attached to Si in 8a or 8b), -1.45 (2 CH 3 attached to Si in 8a or 8b) ppm. 29 Si NMR (119.3 MHz, CDCl 3 , 25°C): δ = -4.29 (2 Si in 8a or 8b), -4.31 (2 Si in 8a or 8b) ppm.…”

“…The residue was further purified with silica gel column chromatography using hexane as eluent providing 0.0378 g (3 %) of 22 as a colorless oil. 1 (25): To α-pinene potassium salt (20.6 mmol) in α-pinene (9.8 mL, 62.0 mmol) were added THF (20 mL) and a diastereomeric mixture of 1-(chlorodimethylsilyl)indenes (23a/23b) (0.9141g, 4.4 mmol) in THF (40 mL) at -72°C. The resulting dark brown reaction mixture was taken into room temperature and stirred there for 2 h before saturated aqueous NH 4 Cl solution (70 mL) was added.…”

Lewis Base Assisted Brønsted Base Catalysis: Direct Asymmetric Allylic Alkylation of Indenes

“…MBH carbonates [18] and substituted indenes were prepared according to literature procedures. [19] Dicholoroethane was distilled from CaH 2 . All other chemicals were used without purification as commercially available.…”

Synthesis, structures and rac/meso isomerization behaviour of bisplanar chiral bis(phosphino-η5-indenyl)iron(II) complexes

“…Reagent grade solvents were dried and distilled prior to use: diethyl ether and tetrahydrofuran from Na/benzophenone; dichloromethane and petroleum ether (50-70°C fraction) from CaH 2 . Diphenylphosphinoindene [16], bis(1-(diphenylphosphino)-g 5 -indenyl)iron(II) [3,14], 1-methylindene [22] and 4,7-dimethylindene [23] were prepared by published procedures. 1,2-dimethylindene and 1,4,7-trimethylindene were prepared from 2-methylindene and 4,7-dimethylindene, respectively, by modifications of the route used to prepare 1-methylindene.…”