Thermodynamics of metal—ligand bond formation: XVII. Base adducts of tin compounds R3SnCl AND R3SnNCS

Thermodynamic data are reported for reaction of tin compounds R₃SnCl and R₃SnNCS (R = Me, Et, Pt, Bu, Ph) with various bases in benzene solution. R₃SnCl form $\text{1}\text{1}$, 5-coordinate adducts of low stability with pyridine or 4-methylpyridine; the slightly higher stability of corresponding adducts of R₃SnNCS is due to entropy effects. Adducts of R₃SnNCS with 1,10-phenanthroline are only a little more stable, showing the reluctance of the tin atom to achieve a coordination number greater than five. N,N,N′,N′-tetramethyl-1,2-diaminoethane gave either $\text{1}\text{1}$ adducts or 5-coordinate $\text{1}\text{2}$ adducts, depending upon the group R and the concentration of R₃SnNCS. Other bases, such as tertiary amines or phosphines also react with R₃SnNCS, but in most cases the reactions are complex and probably involve disproportionation and formation of R₄Sn.