The solution chemistry of organotin compounds. Part 2. Equilibrium and thermodynamic studies of complex formation between dimethyltin dichloride and picolines
- 1 January 1983
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 2
- No. 1,p. 11-13
- https://doi.org/10.1039/p29830000011
Abstract
The donor–acceptor complexes formed between Me2SnCl2 and 2-, 3-, and 4-picolines have been investigated by analysing the concentration and temperature dependence of 1H, 13C, and 119Sn n.m.r. parameters. Detailed explanations of the data are based on the chemical equilibria which occur. It is concluded that two types of complex, 1:1 and 1:2 Me2SnCl2–picoline, coexist in solution. The equilibrium constants (K1 and K2) and the complex formation shifts (ΔAB and ΔAB2) were determined at several temperatures, and the thermodynamic parameters (ΔH°AB, ΔH°AB2, ΔS°AB, and ΔS°AB2) derived. Entropy terms are shown to be responsible for the small free energy change in case of 2-picoline. Enthalpy terms are discussed in relation to the basicity of picolines. Me2SnCl2 was found to be partly hydrolysed by moisture producing 1,3-dichloro-1,1,3,3-tetramethyldistannoxane, and all sample preparations were done in dry boxes to prevent this. 1H and 119Sn n.m.r. data of this distannoxane are also assigned.Keywords
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