CONVENIENT PREPARATION OF HINDERED DIALKYLTIN(IV) DERIVATIVES

Diphenyltin dichloride was reacted with excess Grignard reagent to give dialkyldiphenyltin derivatives, R2Ph2Sn (R2 = 2 neopentyl, 2 trimethylsilyl, 2 neohexyl, 2 cyclohexyl, hexamethylene), in excellent yield when R is hindered but in lower yield when a ring is formed. Heating these compounds with chloroacetic acid cleaved the two phenyl groups in excellent yield to give crystalline bis(chloroacetates). The dialkyltin(IV) bis(chloroacetates) were converted to oxides by reaction with sodium hydroxide. The crystal structure of hexamethylenetin bis(chloroacetate) (R = R(w) = 0.0241) demonstrated that it was a monomer with a C-Sn-C angle of 122.2(3)-degrees having hexacoordinate tin bonded to anisobidentate chloroacetate groups. C-Sn-C bond angles for all compounds in solution were obtained from 1J(119Sn,13C) values. Literature Karplus-type equations for 3J(119Sn,13C) values in trimethyltin derivatives apply approximately to dialkyldiphenyltin derivatives but not to dialkyltin(IV) bis(chloroacetates).