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

Abstract

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(L^1–3)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 that 1–3 are isomorphous and crystallize in the triclinic space group P-1. All the complexes have a similar octahedral [FeN₆] core with two trans-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⋯π interactions link the molecules of 1–3 to 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.

Graphical Abstract

Keywords:

• Synthesis
• triaryltriazole
• crystal structure
• iron(II) complex
• magnetism