Syntheses, structures and magnetic properties of five iron(II) coordination polymers with flexible bis(imidazole) and bis(triazole) ligands

Five iron(II) coordination polymers, {[Fe(bte)(2)(NCS)(2)][Fe(bte)(H2O)(2)(NCS)(2)]}(n) (1), [Fe(bime)(NCS)(2)](n) (2). [Fe(bime)(dca)(2)](n) (3). [Fe(bime)(2)(N-3)(2)](n) (4) and [Fe(btb)(2)(NCS)(2)](n) (5), were synthesized using the flexible ligands 1,2-bis(1,2,4-triazol-1-yl)ethane (bte), 1,2-bis(imidazol-1-yl)ethane (bime) and 1,4-bis(1,2,4-triazol-1-yl)butane (btb), together with NCS-, dicyanamide (dca) and N-3(-). The compound 1 contains two kinds of motifs (double chain and single chain) and forms a three-dimensional hydrogen bonded network; 2 and 3 contain one-dimensional triple chains; and 4 and 5 form two-dimensional (4,4) networks. The coordination anions (NCS-, dca and N-3(-)) and the structural characteristics of the ligands (bte, bime and btb) play an important role in the assembly of the topologies. Magnetic studies reveal that 1-5 remain in the high-spin state over the whole temperature range 2-300 K and no detectable spin-crossover is observed. (C) 2011 Elsevier Ltd. All rights reserved.