Photochemical Synthesis and Ligand Exchange Reactions of Ru(CO)4(n2-alkene) Compounds.

• Autores: Jason Cooke, David E. Berry, Kelli L. Fawkes
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 84, Nº 1, 2007, págs. 115-118
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Irradiation of Ru3(CO)12 in the presence of either methyl acrylate (CH2=CHCO2CH3) or ethylene generates labile Ru(CO)4(?²-alkene) species that readily react with other two-electron donor ligands, such as triphenylphosphine or the more p-acidic alkene dimethyl fumarate (trans-CH3CO2CH=CHCO2CH3), to produce thermally stable Ru(CO)4L compounds. The experiment can be carried out in a variety of ways, from a microscale approach using standard fluorescent lighting (suitable for large class sizes) to a preparative-scale method using more sophisticated equipment and filtered (? > 370 nm) high-intensity light (appropriate for smaller, advanced laboratories). The Ru(CO)4L (L = alkene or P(C6H5)3) compounds are readily characterized by infrared spectroscopy and provide an excellent application of the Dewar�Chatt�Duncanson model to metal�carbonyl and metal�alkene bonding. The student is challenged to correlate the relative reactivities and thermal stabilities of the three Ru(CO)4(?²-alkene) compounds with the electronic properties of the coordinated alkene and to understand the corresponding effect on the CO stretching frequencies in the infrared spectra.