Occurrence of dimeric trimethyltin hydroxide

Abstract

The infrared spectra of trimethyltin hydroxide are examined in the solid state and in solution. These spectra are discussed in terms of a weak coordination of the oxygen atom with the tin atom. Ebulliometric molecular weight determinations of trimethyltin hydroxide in carbon tetrachloride, chloroform or benzene solution indicate a dimeric molecule [(CH 3) 3SnOH] 2. The SnO stretching vibration band in solid trimethyltin hydroxide is observed at 370 cm −1, while in carbon tetrachloride solution it is found in the 500–580 cm −1 region. The OH stretching vibration band which is observed at 3620 cm −1 in the solid shifts to 3658 cm −1 in solution. Only one SnC stretching vibration band is observed at 540 cm −1 in the solid state, while in solution an additional absorption associated with the SnC stretching vibration is observed. These facts suggest that in the solid state trimethyltin hydroxide is a linear polymer in which the planar (CH 3) 3Sn group is bridged by the -O(H)- unit, whereas in solution it has a dimeric structure, in which two SnO groups form a four-membered ring.