Platinum, catalytic activity with functional groups

Ethylenediaminetetraacetic acid or its sodium salt (EDTA) is a well-known com-plexing agent which can form an abundant variety of water-soluble complexes with all metals. EDTA is widely used in industry and environmental studies are concerned with the degradation of its complexes [2] or the bioaccumulation of platinum group metals [3]. Directly related to the aim of this book is the catalytic activity in various carbonylation reactions of the precursor [Ru(EDTA)(H20)], as reported by Taqui Khan and co-workers [4], In fact the two nitrogen and three carboxylate functions bind the ruthenium(III) center, and under a CO atmosphere this complex is reduced to the ruthenium(II) species [Ru(EDTA)(CO)] in which only one carboxylate group... 

Formation of a siloxane network via hydrosilylation can also be initiated by a free-radical mechanism (300-302). A photochemical route makes use of photosensitizers such as peresters to generate radicals in the system. Unfor-timately, the reaction is quite sluggish. Several complexes of platinum such as (jj-cyclopentadienyl)trialkylplatinum(rV) compoimds have been found to be photoactive. The mixture of silicone polymer containing alkenyl functional groups with silicon hydride cross-linker materials and a catalytic amoimt of a cy-clopentadienylplatinum(IV) compound is stable in the dark. Under UV radiation, however, the platinum complex imdergoes rapid decomposition with release of platinum species that catalyze rapid hydrosilylation and network formation (303-308). Other UV-active hydrosilylation catalyst precursors include (acetylacetonate)Pt(CH3)3 (309), (acetylacetonate)2Pt (310-312), platinum tri-azene compounds (313,314), and other sytems (315,316). 

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