Immobilization of phosphines on silica: identification of byproducts via 31P CP/MAS studies of model alkyl-, aryl-, and ethoxyphosphonium salts. Academic Article

abstract

• Immobilizing bifunctional phosphines with ethoxysilane groups on silica often leads predominantly, and sometimes quantitatively, to P(V) side products that occupy space on the surface but cannot bind metal complexes. Although this side reaction is well-known, and dreaded because it leads to leaching of adsorbed catalysts that are not bound covalently, the exact nature of the surface-bound side product was not yet known. With the help of polycrystalline model compounds of the types [R3PEt]+X- and [R3POEt]+X- (R=alkyl, aryl; X=Cl-, Br-, I-, BF4-) and their solid-state NMR characteristics [delta(31P), CSA], it is demonstrated that the side product is an ethylphosphonium salt bound to the surface by a siloxide anion, [R3PEt]+[Si-O]-.

authors

• Bluemel, Janet

published proceedings

• Inorg Chem

author list (cited authors)

• Sommer, J., Yang, Y., Rambow, D., & Blmel, J.

citation count

• 47

complete list of authors

• Sommer, J||Yang, Y||Rambow, D||Blümel, J

publication date

• November 2004

publisher

• American Chemical Society (ACS)  Publisher

published in

• Inorganic Chemistry  Journal

keywords

• 0302 Inorganic Chemistry
• 0306 Physical Chemistry (incl. Structural)

PubMed Central ID

• 15554612

Digital Object Identifier (DOI)

• 10.1021/ic049065j

start page

• 7561

end page

• 7563

volume

• 43

issue

• 24

URL

• http%3A%2F%2Fdx.doi.org%2F10.1021%2Fic049065j