Synthesis, Spectroscopy and Structure of Diorganotin(IV) Schiff Base Complexes

Abstract

Three diorganotin(IV) chelates with a tetradentate Schiff base, H2Vanophen, [H2Vanophen = N,N′-1,2-phenylen-bis(3-methoxysalicylideneimine)] of the type R2Sn(Vanophen) (R = Ph: 1; R = n-Bu: 2; R = Me: 3) have been synthesized by the reaction of R2SnCl2 (R = Ph, n-Bu, Me) and H2 Vanophen in the presence of triethylamine in benzene. The complexes have been characterised by IR and NMR spectroscopy and by elemental analysis. The δ(119Sn) values for the complexes 1 - 3 are -543.0, -414.2 and -398.2 ppm respectively, indicating hexacoordinated Sn centers. These have been ascertained by X-ray crystal structure determinations of 1 and 3. The distances between tin and the two axial carbon atoms in each complex differ not significantly [2.17(1) Å in 1, and 2.100(3) and 2.115(3) Å in 3). The C-Sn-C angles for 1 and 3 are 165.9(4)° and 159.96(9)°, respectively. The solution NMR spectra (1H , 13C, 119Sn) show clearly that the solid state structures are retained in solution.