Synthesis, crystal structures, and magnetic properties of three new iron(II) complexes with pyrrolyl-substituted triaryltriazoles.

Three pyrrolyl-substituted triaryltriazoles, 3-(N-methyl-2-pyrrolyl)-4-(p-R-phenyl)-5-(2-pyridyl)-1,2,4-triazole (L1: R = MeO; L2: R = Cl; L3: R = Br), and their mononuclear iron(II) complexes,trans-[Fe(L1–3)2(NCS)2]∙2MeOH (1: L1;2: L2;3: L3), have been synthesized and characterized by elemental analysis, FT-IR, ESI-MS, and single-crystal X-ray crystallography. Crystallographic studies revealed that1–3are isomorphous and crystallize in the triclinic space groupP-1. All the complexes have a similar octahedral [FeN6] core with twotrans-NCS−ions. Each ligand adopts a chelating bidentate coordination mode via the pyridyl N and one N of the triazole. Intermolecular O–H⋯O hydrogen bonding and C–H⋯πinteractions link the molecules of1–3to form a 1-D chain or 2-D framework. Variable-temperature magnetic susceptibility measurements indicated that all the complexes remained in a high-spin state from 1.8 to 300 K and had a weak antiferromagnetic interaction. [ABSTRACT FROM AUTHOR]