Trichlorostannyl complexes of Ruthenium(II): Synthesis, structure, reactivity and computational studies

Trichlorostannyl complexes [Ru(SnCl3) (Cp')L] (2a-c) were prepared by treatment of optically active half-sandwich chlorocomplexes [RuCl(Cp')L] (1a-c) with an excess of SnCl2.2H2O in ethanol. Treatment of trichlorostannyl complexes 2a-c with NaBH4 afforded trihydridostannyl derivatives [Ru(SnH3) (Cp')L] (3a-c) in moderated yields. Treatment of 2a-c with MgBrMe gave the trimethylstannyl complexes Ru(SnMe3) (Cp')L (4a-c). Alkynylstannyl derivatives [Ru{Sn(C≡CPh)3}(Cp')L] (5a-c) were prepared by treatment of trichlorostannyl compounds 2a-c with an excess of LiC≡CPh in thf. All the complexes present optical activity. The complexes were characterized spectroscopically and by X-ray crystal structure determination of [RuCl(η5-C5Me5)L] (1b), [Ru(SnCl3) (η5-C5Me5)L] (2b), and [Ru(SnCl3) (η5-C9H7)L] (2c). The influence of different ligands on the RuP interaction in several complexes 1a-c, 2a-c and 3a-c was evaluated by DFT calculations. These calculations indicate that [SnCl3]- has a stronger stabilization effect than [Cl]- and the same occurs between C9H7 and C5Me5. These relative stabilities combined with the distortion energies of the fragments produce a stabilizing effect in the RuP bonds of complex 2c that is twice as strong as in the 1b complex.