A Series of Copper-Lanthanide Heterometallic Coordination Polymers Derived from Pyridine-2,3-dicarboxylic Acid and in situ Generated Succinic Acid

A series of copper–lanthanide heterometallic coordination polymers (CPs), [LnCu(2,3‐pydc)2(suc)0.5(H2O)3]·H2O [Ln = La (1), Pr (2), Nd (3), Sm (4), Gd (5), and Eu (6), 2,3‐H2pydc = pyridine‐2,3‐dicarboxylic acid, H2suc = succinic acid], [Ln2Cu3(2,3‐pydc)6(H2O)10]·8H2O [Ln = Eu (7), Tb (8), Dy (9), and Er (10)], and [Ln2Cu(2,3‐pydc)2(suc)(µ2‐OH)2(H2O)2]·2H2O [Ln = Er (11), Yb (12), and Lu (13)], were synthesized by the hydrothermal reactions of LnCl3·nH2O, Cu(NO3)2·3H2O, pyridine‐2,3‐dicarboxylic acid (2,3‐H2pydc), and N,N′‐di(4H‐1,2,4‐triazole)butanamide (dtb). CPs 1–13 possess three types of three‐dimensional (3D) frameworks. In 1–6, the dinuclear Cu2(2,3‐pydc)4 and Ln2(COO)2 units link to each other to form two‐dimensional (2D) layers, which are extended by the suc anions into a 3D framework. In 7–10, the lanthanide ions connect the trinuclear Cu3(2,3‐pydc)6 units into a 3D framework. In 11–13, the mononuclear Cu(2,3‐pydc)2 units bridge the one‐dimensional (1D) lanthanide chains into 2D layers, which are linked by the suc anions into a 3D framework. CP 9 shows a field‐induced slow magnetic relaxation behavior with a Ueff value of 83.7 K. A series of copper–lanthanide heterometallic coordination polymers (CPs) with three types of 3D frameworks and two structural critical points have been successfully synthesized and structurally characterized. The dysprosium‐containing CP shows a field‐induced slow magnetic relaxation behavior.