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

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)(2)Cl-2] (5), trans-[Fe(BPM)(2)(NCS)(2)] (9), [Fe(BPM)(2)Cl](+)(BPh4)(-) (7), [Fe(dmBPM)(2)Cl-2] (6), [Fe(dmBPM)(2)Cl](+)(BPh4)(-) (8), [Fe(TPM)(2)](2+)(Cl-)(2) (10), and [Fe(TPM)(NCS)(2)] (11). The solid-state structures of cis-[Fe(BPM)-Cl-2] (5) and trans[Fe(BPM)(2)(NCS)(2)] (9) were determined by single crystal X-ray diffraction analysis. The compound cis-[Fe(BPM)(2)Cl-2] (5) crystallises as colourless prisms from ethanol and trans-[Fe(BPM)-(NCS)(2)] (9) crystallises as colourless plates from methanol. All complexes were characterised by H-1- and C-13-NMR spectroscopy, infrared and far infrared spectroscopy, and mass spectroscopy. All of the iron(II) poly(1-pyrazolyl)methane compounds display temperature-dependent paramagnetism. U 2002 Elsevier Science B.V. All rights reserved.