Unexpected formation and structure elucidation of mer-[RuCl3(TMSO)(bpy)] derived from [H(TMSO)][trans-RuCl4(TMSO)2] under mild condition

The reaction of [H(TMSO)][trans-RuCl4(TMSO)2] with bpy in ethanol at room temperature resulted an unknown mer-[RuCl3(TMSO)(bpy)] (3) and a known cis-[RuCl2(TMSO)4] (4) (TMSO = tetramethylene sulfoxide, bpy =  2,2′-bipyridine). The crystal structure of mer-[RuCl3(TMSO)(bpy)] (3) was determined by X-ray diffraction. The orange complex crystallizes in triclinic space group P1¯, a = 8.390(2) Å, b = 8.446(2) Å, c = 11.845(4) Å, α = 93.071(13)°, β = 91.228(11)°, γ = 93.831(13)°. The reaction is a new synthetic procedure for 3 and/or 3 and 4 at mild reaction condition from anionic complex involving concurrent substitution and redox reaction.