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)A 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.