Abstract
We have measured the temperature variation of the 13Ca nd 119Sn-NMR spectra of bis (indenyl) tin (IV)compounds, Ph2Sn (C9H7)2 (1) Me2Sn (C9117)2 (2) and (n-Bu)2Sn (C9H7)2 (3), in CDCl3 solution. The free energies of activation (ΔFc) at coalescence temperature (Tc) for interconversion between the two stereoisomers and for metallotropic rearrangement of those compounds are obtained by using the Eyring's absolute rate equation.
The ΔFc values fo r interconversion between the stereoisomers are obtained as 64, 61 and 60 kJ/mol for 1, 2 and 3, respectively (Table 2), and the ΔFc values for metallotropic rearrangement are 67, 65and 63 kJ/mol, respectively (Table 3). For all compounds, the ΔFc values for metallotropic rearrangement are higher than those of interconversion between the stereoisomers.
Thuse, it is found that by elevating temperature bis (indenyl) tin (IV) compounds, 1, 2 and 3 react in two steps, namely, interconversion between the stereoisomers occurs followed by metallotropic rearrangement.
