We have prepared and studied by vibrational and electronic spectrometry of a series
of ferrophthalocyanine complexes with phosphine or phosphite axial ligands [PMe3, P(OMe)3, PPh3, P(OPh)3, PPh(OMe)3 and POH(OEt)2]. With PMe3, P(OMe)3 as ligands, only hexacoordinated
complexes are obtained but with PPh3, P(OPh)3 and POH(OEt)2 as ligands, the coordination number
depends on the FePc:ligand ratio in the reaction mixture. In the ratio 1:1 the complexes thus
formed are pentacoordinated and in the ratio 1:2 hexacoordinated complexes are obtained. In the
electronic spectra of hexacoordinated complexes, two charge-transfer transition bands, one at ~375 nm and the other at ~421 nm can be observed. We attribute the band at 375 nm to charge-transfer
from axial ligand to macrocycle (CT Lax ® Pc) and the band at 421 nm to charge-transfer from
metal to axial ligand (CT Fe ® Lax). In the IR spectra, the position of the nFeN4 band is linked to the
coordination number; in the spectra of pentacoordinated complexes, its frequency is almost the same as that in the FePc spectrum but in hexacoordinated complexes, it moves to high frequencies.

Iron(II) phthalocyanine complexes, Phosphine, Phosphite, Vibrational spectrometry of ferrophthalocyanine complexes