Synthesis, structure, magnetic, spectroscopic and electrochemical behaviour of chloro-iron(III) and -manganese(III) complexes of 2,3,7,8,12,13,17,18-octakis(ethylsulfanyl)-5,10,15,20-tetraazaporphyrin

Abstract

The complexes [M(oespz)Cl][M = MnIII or FeIII; oespz = 2,3,7,8,12,13,17,18-octakis(ethylsulfanyl)-5,10,15,20-tetraazaporphyrinate dianion] have been prepared and their structures determined. The isomorphous structures consist of stacked dimers. Monomers, within each dimer, are slipped and faced in trans fashion respect to the M–Cl bond. Weak interdimer interactions arise from Cl S contacts. Intradimer interactions are provided by relatively long M S and N (pyrrole) S contacts. Magnetic susceptibility measurements revealed that [Mn(oespz)Cl] is a high-spin (S= 2) complex with weak antiferromagnetic coupling between the MnIII. The toluene frozen-glass EPR spectrum of [Fe(oespz)Cl] seems to be consistent with a S= ground state, whereas the polycrystalline powder EPR spectrum at 4.2 K and magnetic susceptibility data are better rationalized in terms of a S=5//2 and ½ admixture. The crowding of the UV/VIS spectra of both complexes and the red shift of the Soret and Q bands of [Fe(oespz)Cl] are related to the effects of the peripheral ethylsulfanyl groups on the porphyrazinato ring. Both compounds show characteristic NIR absorptions. Voltammetric data are consistent with the tendency of the porphyrazinate ligand to stabilize the lower oxidation states of metals relative to phthalocyanines and porphyrins

Electrochemical metallization of self-assembled porphyrin monolayers

“…The cyclic voltammogram shows the Fe(II)/Fe(I) redox-couple at a potential of approximately -1.3 V relative to Ag|0.01 mol L -1 AgNO 3. The peak potentials are in agreement with recently published results for Fe-porphyrins in solution [20,21]. The cyclic voltammograms of Fe-porphyrin monolayers have characteristics typical of molecular monolayers.…”

Biphasic Voltammetry and Spectroelectrochemistry in Polymer of Intrinsic Microporosity—4-(3-Phenylpropyl)-Pyridine Organogel/Aqueous Electrolyte Systems: Reactivity of MnPc Versus MnTPP

“…Data in Fig. 4b show spectral changes for nine potential steps with the Soret band shifting from 663 nm (reduced form) to 726 nm (oxidized form) consistent with literature reports [40]. A similar mechanism (Eq.…”

Synthesis, structure and properties of coordination compounds of iron phthalocyanines and their analogues

“…In the series of `acidic' porphyrazine iron complexes, octaethyl-, 57,140 octaphenyl- 141,142 and octa(ethylthio)porphyrazine 143 derivatives were studied. These complexes were prepared either by the reactions of the corresponding m-oxo dimers 57, 141 ± 143 or anionic dihydro complexes 143 with acids or by ligand exchange reactions. 140 Based on the data from magnetic susceptibilities and on the parameters of the MoÈ ssbauer and electronic absorption spectra in frozen matrices (Table 12), the octaethyl-and octaphenylporphyrazine complexes were assigned to iron(III) derivatives with intermediate (S = 3/2) spin.…”