Hybrid Open Networks (MIL 16):  Synthesis, Crystal Structure, and Ferrimagnetism of Co₄(OH)₂(H₂O)₂(C₄H₄O₄)₃·2H₂O, a New Layered Cobalt(II) Carboxylate with 14-Membered Ring Channels

Abstract

A new layered cobalt succinate, Co4(OH)2(H2O)2(C4H4O4)3·2H2O, was prepared under hydrothermal conditions at 180 °C from a 1:1.5:4:120 mixture of Co(II) chloride hexahydrate, succinic acid, potassium hydroxide, and water. The structure was solved by single-crystal X-ray diffraction: P1̄, a = 10.181(2), b = 10.668(2), c = 12.857(2) Å, α = 112.97(3)°, β = 91.24(3)°, γ = 117.96(3)°, V = 1099.1(4) Å3, Z = 2, 5511 F 2 values with I = 2σ(I), R1 = 0.045 and wR2 = 0.114. The title compound presents a structure constituted by the stacking along [100] of metal oxide layers in which 14-membered ring windows appear. Succinate anions linked the cobalt atoms within each layer. From magnetization measurements, this compound is ferrimagnetic below 10 K.

Building Units Design and Scale Chemistry

“…The HTB structure topology is found (Fig. 12) using bricks as di!erent as single octahedra, SBU-6 hexamers (in MIL-HTB described above), tetramers of edge-sharing octahedra in MIL-16, a porous cobalt succinate (39), and even the three-dimensional intercalation complex between idarubicine and the hexanucleotide d(CGATCG) (40), in which the size of the channel becomes more than 36 A s !. The example of the cobalt succinate has the advantage of showing that the resulting topology is independent of the chemical objects used for the synthesis.…”

Crystal structure of bis(aquasamarium) trisuccinate, Sm2(H2O)2(C4H4O4)3

“…The aqua ligands donate hydrogen atoms to carboxylate oxygen atoms to form hydrogen bonds (d(0 ~0) = 2.731 Â -2.925 Â), which make a significant contribution to stabilization of the crystal structure. Bond lengths and angles within the succinate anions exhibit normal values [8,9]. …”

Crystal structure of bis(aquapraseodymium) trisuccinate, Pr2(H2O)2[O2C(CH2)2CO2]3

“…The aqua ligands donate hydrogen atoms to carboxylate oxygen atoms to form hydrogen bonds (d(O···O) = 2.728 Å -2.908 Å), which make a significant contribution to stabilization of the crystal structure of the title praseodymium compound. Bond lengths and angles within the succinate anions exhibit normal values [3][4][5][6]. The title compound has a structure different from Er 2(H2O)4(C4H4O4)3 · 6H2O, in which the edge-shared [Er 2O16] polyhedra of the nine-coordinated Er atoms are bridged by the twisted succinato groups into ribbon-like chains and further interconnected by the bischelating succinato groups to form open layers with the lattice water molecules between them [7].…”