At. Baker et al., METAL-COMPLEXES OF 1,3-BIS(PYRIDIN-2-YL)PYRAZOLE - SPECTRAL, MAGNETICAND STRUCTURAL STUDIES, Australian Journal of Chemistry, 48(6), 1995, pp. 1071-1079
Bis(ligand) iron(II) and nickel(II) complexes of the asymmetric triden
tate ligand 1,3-bis(pyridin-2-yl)pyrazole, L, have been prepared. The
iron(II) complex, [FeL(2)] [PF6](2), is high-spin in the solid state o
ver the temperature range 304-102 K, with a magnetic moment of 5 . 27
BM at room temperature. The crystal structure of bis(1,3-bis(pyridin-2
-yl)pyrazole)iron(II) bis(hexafluorophosphate) has been determined by
single-crystal X-ray diffractometry. The compound crystallized as yell
ow prisms, with the structure being disordered in the tetragonal space
group P (4) over bar 2(1)c with Z = 2. Crystal data a = b = 8 . 785(1
) Angstrom, c = 19 . 804(6) Angstrom. The iron(II) centre is in an N-6
environment, where the six donor nitrogen atoms are provided by the t
wo tridentate heterocyclic ligands. The complex cation has an approxim
ately octahedral structure exhibiting tetragonal compression. The obse
rved Fe-N(pyridine) and Fe-N(pyrazole) distances are 2 . 308(4) and 2
. 019(7) Angstrom respectively, with the Fe-N(pyridine) distance being
the longest observed to date.