IR AND UV-VISIBLE SPECTRA OF IRON(II) PHTHALOCYANINE COMPLEXES WITH PHOSPHINE OR PHOSPHITE

Abstract

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 n FeN4 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.


(Received September 10, 2001; revised February 26, 2002)


Bull. Chem. Soc. Ethiop. 2002, 16(1), 73-79.