Synthesis, crystal structure and NMR of [Na(DB18C6)(CH3CN)]3[α-AsM12O40] (M = Mo/W)

Two super-molecular complexes [Na(DB18C6)(CH3CN)]3[α-AsM12O40] (M = Mo/W) were obtained by solvothermal reaction and characterized by IR,1H 13C and gUMBC NMR, X-ray. The result reveals that the complex consists of a [α-AsM12O40]3− (M = Mo/W) anion with α-Keggin structure, and three complex [Na (DB18C6)(CH3CN)]+ cations in which every sodium ion is located in the cavity of dibenzo-18-crown-6 with 6 Na–O bonds and coordinated with one of the terminal O atom of [α-AsM12O40]3− (M = Mo/W) and the N atom of CH3CN from two sides of the distorted DB18C6 plane, respectively. The three terminal O atoms linked with sodium ion are from a single M3O13 (M = Mo/W) triplet of the α-Keggin metalatoarsenate anion, and M–Ob (M = Mo/W) bonds exhibit alternating single–double bond character.