Synthesis and structures of three, four, and six-coordinate monomeric tin(II) and tin(IV) compounds containing η2-ketiminate ligands

A series of Sn(II) and Sn(IV) compounds containing ketiminate ligands were synthesized. Reactions of SnCl2 with 1 or 2 equiv. Li[OCMeCHCMeNAr] (where Ar = 2,6-diisopropylphenyl) generate [OCMeCHCMeNAr]SnCl (1) and [OCMeCHCMeNAr]2Sn (2) in moderate yield, respectively. Similarly, reacting SnCl4 with 2 equiv. Li[OCMeCHCMeNAr] yields a six-coordinated [OCMeCHCMeNAr]2SnCl2 (3). Divalent tin compound 2 can be oxidized with I2 in diethyl ether to generate tetravalent tin compound [OCMeCHCMeNAr]2SnI2 (4) in moderate yield. Compounds 1–4 have been characterized by 1H and 13C NMR spectroscopy and have been analyzed by X-ray crystallography. Theoretical calculation found that the bonding of ketiminate ligands and tin atom in compound 2 has a strong ionic character.

Graphical abstractA series of divalent and tetravalent tin compounds containing mono-anionic ketiminate ligands were synthesized. The divalent tin compound 1 can be easily oxidized with iodine to form a tetravalent tin compound 4. DFT calculation shows that the nonbonding electrons of Sn(II) are mainly localized on the 5s orbitals and the Sn–(N–O) bond has a strong ionic character.Figure optionsDownload full-size imageDownload as PowerPoint slide