Mononuclear iron(II) coordination compounds with tris(pyrazol-1-yl)methane (HC(Pz)₃) described as [Fe{HC(Pz)₃}₂]A₂ × nH₂O, where A = Cl⁻, Br⁻, I⁻, 1/2 SO ₄ ²⁻ , n = 0–7, were synthesized. The compounds were studied by static magnetic susceptibility measurements, IR and UV/Vis spectroscopy, and powder X-ray diffraction. The crystal and molecular structures of all compounds were determined by single crystal X-ray diffraction.

We review here new advances in the synthesis and investigation of iron(II) coordination compounds with tris(pyrazol-1-yl)methane and its derivatives as ligands. The complexes demonstrate thermally induced spin crossover accompanied by thermochromism. Factors that influence the nature and temperature of the spin crossover are discussed.

Methods of synthesis of iron(II) complexes containing cluster closo-borate anions—[Fe(Htrz)3]B10Cl10 ( I) (HTrz is 1,2,4-triazole), [Fe(NH2Trz)3]B10Cl10 · 2H2O ( II) (NH2Trz is...

Coordination compounds based on copper(ii) halides with 4H-1,2,4-triazolo[1,5-a]benzimidazole (L) and its derivatives with the compositions [CuL₂Hal₂]·nH₂O.