J. Pinkas et al., Preparation and solid-state characterization of nickel(II) complexes with 1 '-(diphenylphosphino)ferrocenecarboxylic acid, NEW J CHEM, 25(9), 2001, pp. 1215-1220
1'-(Diphenylphosphino)ferrocenecarboxylic acid (Hdpf) reacts with nickel(II
) halides and nickel(II) thiocyanate to give the paramagnetic complexes [Ni
X2(Hdpf-kappaP)(2)] (X = Cl, 1; Br, 2; I, 3) and the diamagnetic planar iso
thiocyanato complex [Ni(SCN-kappaN)(2)(Hdpf-kappaP)(2)] (4), respectively.
In situ neutralization of Hdpf followed by reaction with nickel(II) sulfate
affords the salt [Ni(dpf)(2)] (5). The halide complexes 1-3 easily undergo
dissociative decomposition in polar donor solvents; compound 5 is insolubl
e in all common solvents. All compounds were characterized by IR and UV/vis
spectroscopies and magnetic measurements in the solid state. The solid-sta
te structure of the solvate 4 . 2CHCl(3) was determined by single-crystal X
-ray diffraction. A series of complexes, including the ligand Hdpf and its
Ca salt (6) as reference compounds, were further studied by X-ray photoelec
tron spectroscopy. Spectral data and magnetic measurements indicate compoun
d 5 contains the dpf(-) anion as a P,O-coordinated ligand.