Homochiral Laminar Europium Metal–Organic Framework with Unprecedented Giant Dielectric Anisotropy

Hydrothermal (deuteratothermal) reaction of L ‐ethyl lactate (Lig‐Et) with Eu(ClO 4 ) 3 ⋅6 H 2 O gives colorless block crystals of [Eu(Lig) 2 (X 2 O) 2 ][ClO 4 ] ( 1 , X=H; 2 , X=D) both of which possess a two‐dimensional laminar homochiral framework. Single‐crystal dielectric measurements reveal that 1 and 2 display a giant dielectric anisotropy approximately exceeding 100 and large isotopic effect with about 54 % enhancement along the a axis. Their ferroelectric features further confirm this respect. Crystal parameters: 1 , C 6 H 14 ClO 12 Eu, M r =465.58, monoclinic, C 2 , a =8.6786(6), b =8.3965(6), c =10.2153(7) Å, β =92.040(1)°, V =743.92(9) Å 3 , Z =2, ρ calcd =2.079 Mg m −3 , R 1 =0.0508, wR 2 =0.1239, μ =4.448 mm −1 , S =1.043; Flack=0.04(5). 2 : C 6 H 10 D 4 ClO 12 Eu, M r =469.61, monoclinic, C 2 , a =8.689(2), b =8.410(2), c =10.224(3) Å, β =92.057(4)°, V =746.7(3) Å 3 , Z =2, ρ calcd =2.089 Mg m −3 , R 1 =0.0465, wR 2 =0.1150, μ =4.432 mm −1 , S =1.058; Flack=0.02(5).