Organotin(IV) Derivatives of Some O,C,O-Chelating Ligands

The series of organotin(IV) complexes L 1 - 3 SnPh n Cl 3 - n, where L 1 - 3 are O,C,O-chelating ligands (called the pincer ligands), 2,6-bis(alkoxymethyl)phenyl-, 2,6-(ROCH 2 ) 2 C 6 H 3 - (L 1, R = Me, L 2, R = i -Pr, L 3, R = t -Bu, n = 3−0), have been synthesized and characterized by 1 H, 13 C, and 119 Sn NMR spectroscopy, MS-ESI spectrometry, and elemental analysis. The structure of selected compounds L 1 SnPh 3 ( 1 ), L 1 SnPh 2 Cl ( 2 ), L 1 SnPhCl 2 ( 3 ), L 1 SnCl 3 ( 4 ), L 2 SnPhCl 2 ( 7 ), and L 3 SnPhCl 2 ( 11 ) was studied by X-ray crystallography and 119 Sn CP/MAS NMR spectroscopy in the solid state. The determination of crystal structures reveals the similarity of all the shapes of coordination polyhedra. The deformations of the shapes of coordination polyhedra depend on the degree of donor−acceptor Sn−O interaction (from very weak (interatomic distance Sn−O 2.963(1) Å) to medium-strong (2.475(1) Å)), which increases with increasing Lewis acidity of the tin atom in the L 1 - 3 SnPh n Cl 3 - n entities and decreases with increasing steric demands of substituents R (from Me to t -Bu). NMR spectroscopy indicates a similar structural arrangement of the studied compounds in solution.