Catalysts for selective aerobic oxidation under ambient conditions - Advances in Catalytic Activation of Dioxygen by Metal Complexes - page 252

pronounced in heterogeneous systems if perfluorinated polyethers (PFPE oils)
are used as a solvent (see section 16).
This co-catalysis by Cu(II) can be attributed to the formation of Au(III)-Hal-
Cu(II) complexes, where Hal is or The oxidation of CEES by this
Au(III)/Cu(II) is more facile due to the additional withdrawal of
electron density from Au(III) by Cu(II) (a more electropositive Au center results
in an increase in the overall reaction rate).
Au(III)-Hal-Cu(II) moieties are precedented in the literature. For example, a
copper(II) chloroaurate(III) complex with a Au(III)-Hal-Cu(II) unit is
formed by the neutralization of with and has been
characterized (GMELIN registry number 177659). Additionally, a
withdrawal of electron density from Au(III) by Cu(II) makes the Au(III) -
ionic bond stronger, resulting in a less favourable ligand substitution of
nitrate by CEESO, and consequently less product inhibition.
15. SOLVENT EFFECTS
Acetonitrile is a polar organic solvent and therefore many inorganic salts and
organic compounds are reasonably soluble in it. Additionally it is extremely
robust towards oxidation and is aprotic. Therefore most of the research
reviewed here involved the use of acetonitrile as the solvent. However, it is
rather toxic (40 ppm is the practical exposure limit (PEL),
http://www.msdsonline.com) limiting its use in personal care products including
topical skin protectants (TSPs) and other skin creams. Another