Opening the paddlewheel: unusual coordination of [Mo2] dumbbells in the chain structures of A[Mo2(CF3SO3)5]·2CF3SO3H (A = Na, Rb, Cs)†
Abstract
The reaction of Mo(II)acetate, concentrated triflic acid and the alkaline metal triflates A(CF3SO3) (A = Na, Rb, Cs) in sealed glass ampoules at 110 °C yielded red single crystals of A[Mo2(CF3SO3)5]·2CF3SO3H (A = Na: triclinic, P-1, Z = 4, a = 13.714(1) Å, b = 14.339(1) Å, c = 21.340(2) Å, α = 81.78(1)°, β = 75.21(1)°, γ = 62.65(1)°; A = Rb/Cs: monoclinic, P21/m, Z = 2, a = 11.561(1)/11.584(1) Å, b = 14.817(1)/14.9472(8) Å, c = 11.6208(1)/11.744(1) Å, β = 112.38(1)/113.48(1)°). The crystal structures contain dumbbell shaped [Mo2] moieties surrounded by three chelating and four monodentate triflate anions leading to an opening of the typical paddlewheel fragment at one of its edges. The monodentate triflate anions are connected to further [Mo2] dumbbells leading to infinite anionic chains according to ∞1[Mo2(CF3SO3)3/1(CF3SO3)4/2]−. The charge balance is achieved by the alkaline metal ions that are additionally coordinated by