Silicon complexes with Group 12 metals

Donor-bridged bis(silylene) complexes (Equation (4)) are now known for all the group 6 metals.72-74 For example, when CpCr(CO)3 is photolyzed with HSiMe2SiMe2OMe, the product is 26 (M = Cr X = OMe). Structural data for members of this family show that the four-membered ring is folded (internal dihedral angle for 26 with M=Cr, X = OMe is 162.4°), and this is attributed to steric repulsion between CO and silicon-bound Me groups. The fluxional... 

Studies of complexes with bonds between group 8 metals and silicon up to 1997 are adequately covered in the review by Corey and Braddock-Wilking, and overlap with this review is avoided in the discussion below. 

Thus, the direct synthesis of phenylchlorosilanes produces a complex mixture, which, apart from phenyltrichlorosilane, diphenyldichlorosilane, phenyldichlorosilane and triphenylchlorosilane, also contains silicon tetrachloride, trichlorosilane, benzene, solid products (diphenyl and carbon) and a gaseous product (hydrogen). It also forms high-boiling polyolefines, which are part of tank residue and can deposit on contact mass, reducing its activity. It should be kept in mind that the production of phenylchlorosilanes requires silicon with a minimal impurity of aluminum, because the aluminum chloride formed contributes to the detachment of the phenyl group from phenylchlorosilanes at higher temperature. The harmful effect of aluminum chloride is counteracted by the addition of metal salts to contact mass, which form a nonvolatile and nonreactive complex with aluminum chloride. 

Fig. 8.3 Warren R. Roper (born in 1938) studied chemistry at the University of Canterbury in Christchurch, New Zealand, and completed his Ph.D. in 1963 under the supervision of Cuthbert J. Wilkins. He then undertook postdoctoral research with James P. Collman at the University of North Carolina at Chapel Hill in the US, and returned to New Zealand as Lecturer in Chemistry at the University of Auckland in 1966. In 1984, he was appointed Professor of Chemistry at the University of Auckland and became Research Professor of Chemistry at the same institution in 1999. His research interests are widespread with the emphasis on synthetic and structural inorganic and organometallic chemistry. Special topics have been low oxidation state platinum group metal complexes, oxidative addition reactions, migratory insertion reactions, metal-carbon multiple bonds, metallabenzenoids and more recently compounds with bonds between platinum group metals and the main group elements boron, silicon, and tin. His achievements were recognized by the Royal Society of Chemistry through the Organometallic Chemistry Award and the Centenary Lectureship. He was elected a Fellow of the Royal Society of New Zealand and of the Royal Society London, and was awarded the degree Doctor of Science (honoris causa) by the University of Canterbury in 1999 (photo by courtesy from W. R. R.)...

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