The first crystal structures of mixed chalcogen derivatives SnR2[(OPPh2)(SPPh2)N]2(R = Me or Ph)

Abstract

The compounds SnR₂[(OPPh₂)(SPPh₂)N]₂(R = Me, Buⁿ, CH₂Ph or Ph) were prepared by metathesis reactions between SnR₂Cl₂ and K[(OPPh₂)(SPPh₂)N] in toluene. Reactions between SnR₃Cl (R = Me or Ph) and K[(OPPh₂)(SPPh₂)N](1 : 1 molar ratio) in boiling toluene also produced the dimethyl- and diphenyltin(IV) derivatives as redistribution products. The same reactions in chloroform at room temperature afford the corresponding triorganotin(IV) compounds. The compounds were characterized by means of IR and multinuclear NMR spectroscopy. The crystal and molecular structures of SnR₂[(OPPh₂)(SPPh₂)N]₂(R = Me 1 or Ph 2) derivatives were determined by X-ray diffractometry. Both compounds exhibit very similar spirobicyclic structures, with the tin atom as spiro atom. The ligand moieties are monometallic biconnective (bidentate) through both oxygen and sulfur atoms [Sn–S 2.758(1) in 1 and 2.680(4) in 2, Sn–O 2.199(2) in 1 and 2.189(5)Å in 2]. The co-ordination geometry around the central metal atom is octahedral, with C–Sn–C, O–Sn–O (trans) and S–Sn–S (trans) angles of 180°. The conformation of the six-membered SnOSP₂N inorganic rings is twisted boat.