this instrument infrared ir spectra were obtained using a digilab fts 60 fourier transform ir spectrometer interfaced with a hewlettpackard model 5890a gas chromatograph at the chromatographic conditions detailed above spectra are obtained in a 250 u00b0 c cell composed of gold coated capillary glass tubing synthesis of the tetrabutenyltins presented no great difficulty as long as the grignard reagent was present in large excess to assure complete alkylation the tetrabutenyltins were all stable as neat compounds and in inert solvents the tributenyltin bromides exhibited considerable variation in stability tri 2 butenyltin bromide was so reactive with the synthesis side products that it could not be isolated although gas chromatographic retention times and mass spectra could be obtained on products in the reaction mixture tri 1 butenyltin bromide and to a lesser extent tri 3 butenyltin bromide tended spontaneously to form black precipitates during solvent evaporation of the crude mixture prior to column chromatography clean up if the distillation flask were warmed under these conditions alkenyltin compounds were identified containing various numbers of eight carbon groups in the mixture once purified tri 3 butenyltin bromide and tri 1 butenyltin bromide were stable as neat compounds and in inert solvents progress of the synthesis reactions and purity of the products were monitored using gc ms differentiation of the tetrabutenyltins and tributenyltin bromides was achieved by gas chromatographic retention times mass spectrometry and ir spectrometry where cis trans isomers were present in the starting butenyl halides a mixture of isometric butenyltins was formed although these isomers could be separated by gas chromatography there was no attempt to separate them chemically and purify them these.