Soluble Substituted μ‐Oxo(phthalocyaninato)iron(III) Dimers

Attempts to prepare various peripheral tetra‐ and octasubstituted (phthalocyaninato)iron derivatives R n PcFe [ n = 4: R = CH 2 OEt ( 6e ), CO 2 Et ( 6h ), CO 2 ‐ n ‐C 6 H 13 ( 6l ), O(2‐Et‐ n ‐C 6 H 13 ) ( 6j ), OCH 2 C(CH 3 ) 3 ( 6k ), OCH 2 C(CH 3 ) 2 CH 2 Ph ( 6l ); n = 8: R = CH 2 CH(CO 2 Me)CH(CO 2 Me)CH 2 ( 6f ), CH 2 CH(CO 2 Et)‐CH(CO 2 Et)CH 2 ( 6g ), O‐ n ‐C 8 H 17 ( 6m ), O(2‐Et‐ n ‐C 6 H 13 ) ( 6n )] by starting from the corresponding substituted phthalonitriles led to substituted (μ‐oxo)bis[(phthalocyaninato)iron(III)] compounds [R n PcFe] 2 O. The tert ‐butyl‐ and ethyl‐substituted systems [ t Bu 4 PcFe] 2 O ( 6c ) and [Et 4 PcFe] 2 O ( 6d ) were reinve‐stigated. UV/Vis, FD mass, Mössbauer, NMR as well as ESR spectroscopy was used to characterize the complexes [R n PcFe] 2 O to furnish evidence for the presence of Fe‐O‐Fe moieties in [R n PcFe] 2 O. The UV/Vis data reported for [R n PcFe] 2 O as well as their spectral behavior in pyridine correspond to unsubstituted [PcFe] 2 O. Mössbauer spectra of [R n PcFe] 2 O show that the complexes were obtained as a mixture of two isomeric μ‐oxo compounds A (δ Fe = 0.22 mm s ‐1 , Δ E Q = 1.33–1.39 mm s ‐1 ) and B (Δ Fe = 0.33–0.36 mm s ‐1 , Δ E Q = 0.39–0.53 mm s ‐1 ), whose Mössbauer parameters are comparable to [PcFe] 2 O μ‐oxo(2) and μ‐oxo(1), respectively. Mössbauer spectral data of [R n PcFe] 2 O indicate high‐spin ( S = 5/2) Fe III centers. NMR‐spectra of [R n PcFe] 2 O ( n = 4: R = t Bu, Et, O(2‐Et‐ n ‐C 6 H 13 ), OCH 2 C(CH 3 ) 2 CH 2 Ph; n = 8: R = O‐ n ‐C 8 H 17 , O(2‐Et‐ n ‐C 6 H 13 ) give further evidence for μ‐oxo bridged structures.