J. G. Noltes

The synthesis and properties of some organometallic compounds containing group IV (Ge, Sn)-group II (Zn, Cd) metalmetal bonds

Abstract The reactions of triphenylgermane and triphenyltin hydride with coordinatively saturated organozinc or organocadmium compounds give organometallic complexes containing Group IV (Ge, Sn)-Group II(Zn, Cd) metalue5f8metal bonds. The 2,2′-bipyridine complexes show solvent-dependent charge-transfer absorptions in the visible region. The occurrence of charge transfer may account for the observation that the metal-metal stretching frequencies of the Bipy complexes are consistently lower than those of the corresponding TMED complexes.

The chemistry of organometallic compounds containing a tinzinc bond. The occurrence of 1,2-intermetallic migrations of organic groups

Abstract Triphenyltin-zinc compounds are easily accessible by means of hydrostannolysis reactions of zincue5f8carbon bonds in coordinatively saturated organozinc compounds. The chemical behaviour of (triphenyltin)zinc chloride was found to depend greatly on the coordination state of the zinc atom. In the absence of strongly coordinating ligands, 1,2-intermetallic migration of a phenyl group from tin to zinc occurs. In consequence it behaves as a phenylating reagent. The strongly coordinating ligand N,N,N′N′ -tetramethylethylenediamine prevents or reverses this phenyl migration. A possible structure for uncomplexed (triphenyltin)zinc chloride is discussed.

Triphenyltinmagnesium bromide. Evidence for the occurrence of diphenylstannene stabilizied by coordination

Whereas organotin alkali metal derivatives have been widely investigated’ information on organotin mtignesium derivatives is restricted to a brief report on the solution chemistry of (Ph,Sn),Mg’. Evidence has been presented for the existence in solution of Ph,GeMgC13*4 and Ph,PbMgBr’, but these compounds have not been isolated. The isolation of triphenyltin derivatives of the Group IIB metals Zn and Cd has recently been reported6. The hydrostannolysis of reactive metal-carbon bonds offers a particularly useful route to compounds containing metal-tin bonds6-‘. This reaction has now been applied to a study of the triphenyltin Grignard reagent_ The reaction of triphenyltin hydride with an equimolecular amount of ethylmagnesium bromide-triethylamine complexQ*‘0 in diethyl ether at 15-O” results in selective hydrostannolysis of the Mg:C bond as evidenced by the quantitative formation of ethane :

The reaction of organotin halides with zinc. The occurrence of 1,2-intermetallic shifts

Abstract The reaction of organotin halides with zinc proceeds via the initial formation of reactive organotin-zinc compounds. The nature of the final reaction products depends on the reaction conditions. In aprotic solvents, in the absence of strongly coordinating ligands, tetraorganotin compounds are formed via alkylation or arylation by intermediate organozinc compounds. The latter are produced by 1,2-intermetallic shifts of organic groups in the initial organotin-zinc reaction product, and from redistribution and transmetallation reactions. In the presence of proton donors, the organozinc intermediates are protolysed to the corresponding hydrocarbons. Strongly coordinating ligands prevent the 1,2-shifts, and hexaalkyl- or hexaarylditin compounds are formed. The unexpected formation of tetramethyltin form the reaction of mixed methylphenyl-tin monochlorides with zinc appears to involve a redistribution reaction between tetraorganotin compounds and zinc chloride. The reactions of diphenyltin dichloride and phenyltin trichloride with zinc give triphenyltin chloride, again via initially-formed organotin-zinc compounds.