Iron(II) complexes containing poly(1-pyrazolyl)methane ligands

Article abstract of DOI:10.1016/S0022-328X(02)01471-7

A number of iron(II) compounds containing the poly(1-pyrazolyl)methane ligands bis(1-pyrazoyl)methane (BPM, 3), bis(3,5-dimethyl-1-pyrazolyl)methane (dmBPM, 4), and tris(1-pyrazolyl)methane (TPM, 2), were synthesised and characterised: cis-[Fe(BPM)₂Cl₂] (5), trans-[Fe(BPM)₂(NCS)₂] (9), [Fe(BPM)₂Cl]⁺ (BPh₄)^- (7), [Fe(dmBPM)₂Cl₂] (6), [Fe(dmBPM)₂Cl]⁺ (BPh₄)^- (8), [Fe (TPM)₂]²⁺ (Cl^-)₂ (10), and [Fe(TPM)(NCS)₂] (11). The solid-state structures of cis-[Fe(BPM)₂Cl₂] (5) and trans-[Fe(BPM)₂(NCS)₂] (9) were determined by single crystal X-ray diffraction analysis. The compound cis-[Fe(BPM)₂Cl₂] (5) crystallises as colourless prisms from ethanol and trans-[Fe(BPM)₂](NCS)₂] (9) crystallises as colourless plates from methanol. All complexes were characterised by ¹H- and ¹³C-NMR spectroscopy, infrared and far infrared spectroscopy, and mass spectroscopy. All of the iron(II) poly(1-pyrazolyl)methane compounds display temperature-dependent paramagnetism.