Mono-Organotin Oxo-Clusters

Chimie de la Matiere Condensee de Paris, Universite Pierre et Marie Curie-Paris6, Paris, France 

The aim of this chapter is to review and discuss the molecular structures, syntheses, and possible formation mechanisms of the organotin oxo-clusters that follow the formula (RSn) 0 (0H)3,Cl2. 

The n-butyl- and methyltin derivatives have been studied by solution Sn NMR. For the n-butyltin compounds, the observation of a major resonance at -408.6 ppm (in acetone-de) is consistent with six-coordinate tin atoms and with the preservation of the dimeric structure in solution. A similar conclusion does not seem to hold for the methyltin derivative, for which Sn NMR indicates a drop in the coordination of tin (-175.9 ppm in CDCF).  

Such a dimer has also been observed containing bridged organotins. Indeed, the hydrolysis of 1,3-bis(trichlorostannyl)propane, in water, yields a solid where the dimers are associated by the alkyl spacer in infinite chains.  

On the basis of Sn NMR, this oxo-cluster is said to be stable in solution. However, the reported chemical shift (94.3 ppm in CeDe) is quite different from those observed for other CSnOs environments with the same organotin. ° 

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As presented in the Introduction, solid-state " Sn NMR is a complementary tool to X-ray diffraction for the study of organotin oxo-clusters. Mono-organotin derivatives generally exhibit large chemical shift anisotropies and their spectra contain many spinning side The Sn NMR (MAS)... 

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