Synthesis and Crystal Sturcture of a New Praseodymium（Ⅲ）polym煳x：[

A novel polymeric Pr2Cu3 complex of iminodiacetic acid (H2L1=NH{CH2COOH}2) Pr2Cu3(L1)6]n , 1, has been synthesized and structurally characterized. The title complex Pr2Cu3O24N6C24H30 (Mr=1258.97) crystallized in trigonal space group Pc1 (No. 165) with a = 13.424(4), c=14.752(6)(); V=2303(1)()3; F(000)=1226; λ(MoKα)=35.2 cm-1; Dc=1.820 g.cm-3; Z=2. The final R and Rw are 0.072 and 0.081 respectively for 1412 reflections with I>3σ(I). In crystal 1, the Pr3+ ion is nine-coordinated by 6 O atoms from three bidentate chelating carboxylate groups and 3 O atoms from three anti-anti bridging carboxylic groups of six L1 ligands; the Cu2+ ion is six-coordinated by 4 O and 2 N atoms from two pentadentate L1 ligands. Each pair of Pr(Ⅲ) atoms is bridged by three L1 ligands, each of which also chelates with one copper(Ⅱ) ion, thus forming a Pr2Cu3 cluster unit. Such cluster units are cross-linked by flexible L1 ligands into a three-dimensional coordination framework.