cg7010666_si_006.cif (13.56 kB)

Assembly of Iron(II)-Triazole Polymers from 1D Chains to 3D Interpenetrated Frameworks: Syntheses, Structures, and Magnetic Properties

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posted on 02.04.2008 by Zhi-Guo Gu, Yi-Fan Xu, Xin-Hui Zhou, Jing-Lin Zuo, Xiao-Zeng You
By the reactions of FeX2 with α,ω-bis(1,2,4-triazol-1-yl)alkane ligands (X = ClO4, BF4, NCS, and NCSe), a series of novel iron(II) coordination polymers have been synthesized and characterized. Complexes [Fe(btp)3](ClO4)2 (1a), [Fe(btp)3](BF4)2 (1b), and [Fe(btp)2(NCS)2] (2) (btp = 1,3-bis(1,2,4-triazol-1-yl)propane) are infinite 1D-linear chains. [Fe(btb)3](ClO4)2 (3a) and [Fe(btb)3](BF4)2 (3b) (btb = 1,4-bis(1,2,4-triazol-1-yl)butane) are 3-fold interpenetrated α-polonium cubic frameworks. The two sorts of btb ligands with different conformations alternately link to the Fe(II) centers in [Fe(btb)2(NCS)2]·H2O (4) to form a 3D interpenetrating architecture of CdSO4-like topology. When NCSe instead of NCS was used as the framework-regulator, a 2D grid layer [Fe(btb)2(NCSe)2]·2H2O (5) was obtained. The counteranions, spacer length, and conformation of the α,ω-bis(1,2,4-triazol-1-yl)alkane ligands are responsible for the assembled topological architectures. Magnetic studies indicate that all of these iron(II) polymers retain a high-spin ground state upon cooling from 300 to 4 K.