| The fluxional behaviors of organosilicon groups on cyclopentadienyl derivatives were assessed in the presence and absence of late transition metal centers and, in separate work, the catalytic activity of transition metal complexes were examined in a siloxane environment.; Dichloro-methyl-(2,3,4,5-tetramethyl-cyclopentadienyl)-silane CpMe 4H(SiMeCl2) showed reversible variable-temperature 1H, 13C and 29Si NMR spectra without producing either Diels-Alder adducts or decomposition products. The high temperature NMR spectra suggest that these fluxional behaviors result from a silicon sigmatropic rearrangement (barrier 14.9 kcal/mol). CpMe4H(SiMeCl2) was hydrolyzed in the presence of 1,8-bis(dimethylamino)naphthalene to generate the corresponding disilanol compound, CpMe4H{lcub}SiMe(OH)2{rcub}, which did not undergo such rearrangements.; The reaction of disiloxane-bis-1,3-inden-1'-ylanion with FeCl2 produced both stereoisomers of disiloxane-bis(1-indenyl)- ansa-ferrocene Fe(eta5-Inden-1-yl-SiMe2) 2O, each of which has a non-strained metallacycle and non-C 2 symmetrical indenyl coordinating groups. A single crystal X-ray diffraction study confirmed both structures: racemic and meso compounds. Each isomer could be transformed into the other isomer. The conversion was retarded under basic conditions but accelerated under weakly acidic conditions. The mechanism of this behavior, investigated using deuterium labelling experiments, is consistent with a series of successive Si-indenyl 1,5-sigmatropic rearrangements. Equilibrium co-polymerization of Fe(eta5-Inden-1-yl-SiMe2)2O was performed with 1,1,3,3,5,5,7,7-octamethylcyclotetrasiloxane and 1,1,1,3,3,5,5,5-octamethyltrisiloxane under basic conditions to produce green organometallic polymers.; Metal coordination on polymer chains was utilized to prepare mono-functional linear oligo- and polydimethylsiloxane organometallic compounds. These compounds were assessed, as a function of their siloxane chain lengths, on hydrosilylation catalytic activity. (Abstract shortened by UMI.)... |
