Eisen(III)phthaloeyanine: Darstellung und spektroskopische Charakterisierung von [Fe(OR)2Pc(—2)]- (R = H, CH3, C2H5, (CH3)2CH, (CH3)3C), (FePc(—2))2O und FeXPc(—2) (X = F, Cl, Br, I)/ Iron(III)phthalocyanines: Preparation and Spectroscopic Characterisation of [Fe(OR)2Pc(—2)]- (R = H, CH3, C2H5, (CH3)2CH, (CH3)3 C), FePc(—2))2O and FeXPc(—2) (X = F, Cl, Br, I)

Abstract

Abstract The preparation of bis-hydroxophthalocyaninatoferrate(III) and of some of the bis-alkoxo-analogues is described. In the presence of a small excess of OR -(R = H, CH3, C2H5, (CH3)2CH, (CH3)3C) these complexes are stable in most common non-polar solvents and can be isolated as analytically pure bis-triphenylphosphiniminium-(PNP)-salts. Solutions of these complexes react immediately with water and acids. Thus hydrolysis is an easy way to prepare μ-oxo-bis-phthalocyaninatoiron(III). The reaction with mineral acids HX (X = F, Cl, Br, I) precipitates the pure pentacoordinated halogenophthalocyaninatoiron-(III). The electronic absorption spectra have been measured. Besides the typical inner-ligand π-π*-transitions additional bands are observed at ~11,5kK (CT1) and ~20kK (CT 2). These bands are of medium intensity only for FeXPc(-2) (X = Cl, Br, I) especially in the solid state spectra and are probably associated with ligand-to-metal-charge-transfer(CT)-transitions mainly of the Pc → Fe-type but partially mixed with X→Fe. CT 1 and CT2 are assigned to (a1)π → (e,a1)d respectively. This is confirmed by the resonance Raman spectra. On excitation within the range of the CT 2 electronic transition some in-plane stretching-(1595 and 1550 cm -1) and out-of-plane deformation vibrations (350 and 290 cm -1) of the macrocycle as well as the Fe-X-stretching vibrations are resonance Raman enhanced. Combination bands of Fe-X-with Pc-vibrations give strong evidence for coordination of the halide to an axial position of the iron centre. As expected for C4V point symmetry the Fe-X vibrations are IR active, too (ν(Fe-X) for X = F: 475; Cl: 303; Br: 221; I: 193 cm -1). The Fe-O stretching vibration (a1g) is only observed in the resonance Raman spectrum of PNP[Fe(OH)2Pc(-2)] at 495 cm -1 . As a consequence of the strong antiferromagnetic coupling the IR and resonance Raman spectra of (FePc(-2))2O resemble those of closed shell ions. The IR absorption at 822 cm-1 is assigned to the anti-symmetric (a2u) (Fe-O-Fe) deformation mode.