Racemic twin crystals containing left- and right-handed polyoxometalate chains induced by the asymmetric coordination of metal–organic units

Abstract

Two racemic twin crystals containing left- and right-handed polyoxometalates (POMs) chains [Cu(en) 2][Cu(en) 2(H 2O)] 2 [SiW 11CuO 39] · 5H 2O ( D-1 and L-1; en = ethylenediamine) have been synthesized and structurally characterized. Both chiral compounds ( D-1 and L-1) were constructed from the achiral building blocks [SiW 11CuO 39] 6− and [Cu(en) 2(H 2O) n ] 2+ ( n = 0 or 1). The structural chirality is induced by the [Cu(en) 2(H 2O) n ] 2+ units asymmetrically coordinated on the chainlike [SiW 11CuO 39] n 6 n − polyoxoanions, leading to the whole molecules crystallized in the chiral P1 space group. The chiroptical activities of D-1 and L-1 were confirmed by the solid-state circular dichroism spectroscopy. Their electrochemical and electrocatalytic properties were also investigated.