Yttrium silanolate

The yttrium silanolate complex 11 shows good catalytic activity with high anti-Markovnikov regioselectivity in the hydrosilylation of 1-decene (Tablet) [59]. Cationic silanolate rare-earth metal alkyl species derived from 11 were either inactive or exhibited significantly diminished activity, possibly as a result of tight binding of the benzene solvent as well as decomposition of the cationic metal hydride intermediate. 

A homoleptic bulky a,y-diketonate yttrium complex (fod = 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionate) was immobihzed on MCM-41.280 ( s = 1140m g, Vp = 0.93 cm g, dp = 2.7 nm) and a monopodaUy anchored surface species 6 has been proposed (Scheme 12.5). As suggested by FTIR (strong band for the Si-OH stretch vibration) as well as metal and carbon analysis (circa 3.4 wt% Y, fod/Y circa 2) only around half of the silanol population has been consumed [110]. 

Ln = Sc, Y, La), and have been tested as heterogeneous catalyst in the Diels-Alder cyclization of terH-methoxy-3-trimethylsilyloxy-l,3-butadiene with benzaldehyde (Danishefsky transformation of 1,3-dienes), and proved active [51]. The surface yttrium bis-dionate has also been synthesized directly from the molecular precursor [Y( Bu-COCHCO-"C3F7)3] by reaction with MCM-41 surface silanols [51]. 

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