Two series of zinc salts, [EtZn]­[A] and Zn­[A]2, with weakly coordinating anions [A]− as counterions have been prepared, and their activities as catalysts for hydrosilylation reactions of 1-hexene, benzophenone, and acetophenone have been investigated. The counterions and per- and partially chlorinated 1-ammonio-closo-dodecaborate anions [Me3NB12Cl11]− [1]−, [Pr3NB12H5Cl6]− [2]−, [Bu3NB12H4Cl7]− [3]−, and [Hex3NB12H5Cl6]− [4]− were chosen as potential and more readily available alternatives to carborate anions such as [CHB11Cl11]− and [HexCB11Cl11]−. The basicity of anion [4]− was determined as being close to that of the triflimide anion [N­(SO2CF3)2]−, and the fluoride ion affinities (FIAs) of compounds [EtZn]­[2] and Zn­[2]2 are lower than those of the Lewis acids B­(C6F5)3 and Zn­[HexCB11Cl11]2. The higher anion basicity and the resulting lower Lewis acidity of the zinc centers result in low activity in 1-hexene hydrosilylation catalysis and only moderate activity in the hydrosilylation catalysis of benzophenone and acetophenone.

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SIR,—I feel it to be inconsistent with my opinions, and the official position held by me in the Royal College of Surgeons of Edinburgh, that my name should longer continue on the Dental Reform Committee. I beg therefore that it be at once

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