Synthesis and Reactivity of the Metallaborane Complex [Mo(CO)4B3H8]- and the Formation of Mo(CO)4(dppe)

• Craig M. Davis ^[1] ; Megan F. Klein ^[1]
  1. [1] Xavier University

     Xavier University

     City of Cincinnati, Estados Unidos

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 78, Nº 7, 2001, pág. 952
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • In this laboratory exercise the octahydrotriborate anion ([B3H8]-) is synthesized from sodium borohydride (NaBH4) and iodine in diglyme under a nitrogen atmosphere, and the sodium salt is converted to the tetrabutylammonium salt by a simple metathesis. Next, the metallaborane complex [(CO)4MoB3H8]- is prepared by refluxing a solution of Mo(CO)6 and (Bu4N)B3H8 in anhydrous 1,2-dimethoxyethane (glyme) under a nitrogen atmosphere. This solution is transferred via cannula to a flask containing the solid 1,2-bis(diphenylphosphino)ethane (dppe). The ensuing formation of [Mo(CO)4(dppe)] is nearly instantaneous. The syntheses of the two metal complexes proceed in very high yield.This exercise features inert-atmosphere syntheses and multinuclear (1H, 11B, and 31P) NMR spectroscopy and is suitable for upper-level undergraduates. The skills and ideas that are taught or reinforced include a general overview of borane clusters and the isolobal analogy, handling air-sensitive solutions, and internuclear coupling in NMR spectra.