Trianion-Based Catalyst

The Ziegler-Natta catalyst trimethylammonium o-methyl-1-(2-hydroxy Icy do hexyl)-carborane zirconium chloride has been prepared and affixed to a Merrifield resin. When used as a polymerization catalyst for vinyl chloride, t-butyl acrylate, styrene, or ethylene, oligomers with molecular weights 6000 daltons were obtained. 

A solution of methyl carborane (6.32 mmol) dissolved in 20 ml of diethyl ether was cooled to —78°C and then treated with 4.20 ml n-BuLi (6.72 mmol 1.6M in n-hexane) and stirred for 30 minutes. The mixture was warmed to ambient temperature, stirred for 4 hours, and treated with cyclohexene oxide (6.80 mmol) at 0°C. It was then stirred for 6 hours and quenched with 10 ml of water. The organic phase was separated, and the aqueous phase extracted twice with 25 ml of diethyl ether. The combined organics were dried using MgS04 and concentrated. The residue was re-crystallized in n-hexane, and the product was isolated in 86%yield, MP= 101-103°C 

The Step 1 product (5.85 mmol) was dissolved in a solution of potassium hydroxide (32.08 mmol) in 40 ml of 95 % ethanol and then refluxed for 16 hours and concentrated. The residue was dissolved in 20 ml of water and neutralized with hydrochloric acid. Next it was treated with trimethylamine hydrochloride (17.55 mmol) in 7 ml of water. A white precipitate formed which was filtered and dried, and the product was isolated in 77% yield, MP 200°C. 

Preparation of Trimethylammonium o-Methyl-l-(2-Hydroxylcyclohexyl)-Carborane Zirconium Chloride 

The Step 2 product (4.92 mmol) was dissolved in 75 ml of dry THF and then cooled to 0°C and treated with sodium hydride (29.52 mmol 60% dispersion in mineral oil). The mixture was next stirred at ambient temperature for 30 minutes and refluxed for 3 hours. Complete removal of trimethylamine was achieved by passing a stream of argon over the solution and through the condenser during the final 30 minutes of refluxing. Once at ambient temperature stirring was stopped and the clear THF solution was decanted under argon to another vessel. This solution was then treated with ZrCL (4.93 mmol) and stirred for 72 hours at ambient temperature. The mixture was filtered 

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