Synthesis and Structure of Iron(II) Complexes with 1-Methyl-2-pyridin-2-yl-1H- and 1-Methyl-2-phenyliminomethyl-1H-benzimidazoles and Boron Cluster Anions [BnHn]2– (n = 10, 12)

The study addresses the complex formation reactions between iron(II) and benzimidazole (L) derivatives (L¹ = C₁₃N₃H₁₁, L² = C₁₅N₃H₁₃) in the presence of boron cluster anion salts [B_nH_n]^2– (n = 10, 12). The prepared complexes [FeL₃][B_nH_n] were characterized by elemental analysis and IR spectroscopy. The structure of [\({\text{FeL}}_{{\text{3}}}^{{\text{1}}}\)][B₁₀H₁₀] was established by single crystal X-ray diffraction (CCDC no. 2432134). The distorted octahedral environment of the Fe atom is formed by the imidazole and pyridine nitrogen atoms of the three ligand molecules. In the crystal, the \({{{\text{[FeL}}_{{\text{3}}}^{{\text{1}}}{\text{]}}}^{{{\text{2 + }}}}}\) complex has a meridional configuration. The Fe–N bond lengths for the imidazole nitrogen atoms are in the 1.954(8)–1.980(6) Å range, while for the pyridine nitrogen atoms, this range is 1.977(7)–2.011(8) Å.