Thermochemistry of adducts of tin(IV) bromide with ligands containing amide or thioamide groups

The compounds [SnBr4(L)2] (where L is formamide (fa), acetamide (a), N,N-dimethylacetamide (dma), benzamide (ba), thioacetamide (ta), N,N-dimethylthioformamide (dmtf), N,N-dimethylthioacetamide (dmta) or thiobenzamide (tba)) were synthesized and characterized by melting points, elemental analysis, thermal analysis and IR spectroscopy. The enthalpies of dissolution of the adducts, tin(IV) bromide and ligands in methanol were measured and by using thermochemical cycles the following thermochemical parameters for the adducts have been determined: the standard enthalpies for the Lewis acid/base reactions (ΔrHθ), the standard enthalpies of formation (ΔfHθ), the standard enthalpies of decomposition (ΔDHθ), the lattice standard enthalpies (ΔMHθ) and the standard enthalpies of the Lewis acid/base reactions in the gaseous phase (ΔrHθ(g). The mean bond dissociation enthalpies of the tin(IV)oxygen (D̄(SnS)) and tin(IV)sulphur bonds (D̄(SnO)) have been estimated.