- Iron(III)phthalocyanines: Preparation and Spectroscopic Characterisation of (-) (R = H, CH3, C2H5, (CH3)2CH, (CH3)3C), FePc(-2))2O and FeXPc(-2) (X = F, Cl, Br, I)
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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 innerligand ?-?*-transitions additional bands are observed at ca. 11,5 kK (CT 1) and ca. 20 kK (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 CT 2 are assigned to (a1)? -> (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 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 antisymmetric (a2u) (Fe-O-Fe) deformation mode. - Keywords: Bis-hydroxo-iron(III)phthalocyanine, Vibrational Spectra, UV-VIS Spectra, Iron(III)phthalocyanines
- Kalz, W.,Homborg, H.
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p. 470 - 484
(2007/10/02)
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