· (MW 364.70)
(couples alkynes to form hafnacyclopentadienes3)
Physical Data: subl at 80 °C/10-4 mmHg.2a
Solubility: sol hydrocarbons, THF.
Analysis of Reagent Purity: IR, NMR.2
Preparative Method: reduction of Dichlorobis(cyclopentadienyl)hafnium with Magnesium Amalgam under CO atmosphere.2b
Purification: hexane solution is filtered through alumina and cooled to -20 °C to induce crystallization; sublimation at 80 °C/10-4 mmHg.2
Handling, Storage, and Precautions: store and handle under an inert atmosphere. Use in a fume hood.
Dicarbonylbis(cyclopentadienyl)hafnium reacts with alkynes to form hafnacyclopentadiene complexes (eq 1), which may be isolated and purified prior to further manipulations.3 Carbonylated products are not observed, indicating that the carbonyl ligands serve only as labile ligands which are lost during the reaction. Hafnacyclopentadiene complexes prepared by alternate methods have been converted into various 1,3-butadienes (see also Dichlorobis(cyclopentadienyl)hafnium).
- 1. (a) Cardin, D. J. In Dictionary of Organometallic Compounds; Buckingham, J., Ed.; Chapman & Hall: London, 1984; Vol. 2, p 1009. (b) Cardin, D. J.; Lappert, M. F.; Raston, C. L.; Riley, P. I. In Comprehensive Organometallic Chemistry; Wilkinson, G., Ed.; Pergamon: Oxford, 1982; Vol. 3, pp 610-616. (c) Pez, G. P.; Armor, J. N. Adv. Organomet. Chem. 1981, 19, 1. (d) Sikora, D. J.; Macomber, D. W.; Rausch, M. D. Adv. Organomet. Chem. 1986, 25, 317.
- 2. (a) Thomas, J. L.; Brown, K. T. JOM 1976, 111, 297. (b) Sikora, D. J.; Moriarty, K. J.; Rausch, M. D. Inorg. Synth. 1990, 28, 248.
- 3. Sikora, D. J.; Rausch, M. D. JOM 1984, 276, 21.
Thomas E. Snead
Emory University, Atlanta, GA, USA
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