Investigation of the reactions of iron(III) halobisdithiocarbamates with halogens: a novel series of fluxional homobinuclear iron(III) complexes with two different coordination spheres around the magnetic centers

Mass spectral and thermogravimetric studies of some iron(III) binuclear complexes with bridging thiuram disulfide ligands

“…The dihalide iron(IIl) dimers were prepared as previously reported [5]; they were recrystallized several times from methylene chloride-cyclohexane mixtures and dried under vacuum. The thermal decomposition was carried out on a TGS-2 Perkin-Elmer thermobalance at a heating rate of 5 deg/min, in the temperature range 20-1000 ~ with a sample mass of 5 mg and :c-Al20 3 as reference.…”

“…Fragmentation patterns are given and possible mechanisms are discussed.In addition to the variety of products formed [1][2][3][4] during the reaction of iron(Ill) halobisdithiocarbamates, [Fe(Rzdtc)2X ], with halogens, X' 2, some novel homobinuclear iron(Ill) complexes with two different coordination spheres around the magnetic centers have also been synthesized and studied [5], The formation of these products, formulated as Fe2(R2dtc)2(tds~ [R = Me; R 2 = Pyrr; X = CI, Br; and X' = Br, I], depends on the natures of both the molecular halogen and the reagent complex, as well as on the reaction conditions. In particular, the proposed mechanism [5] which accounts for the synthesis of these compounds involves as a first step the formation of the corresponding dihalide-bridged dimers, [Fe(R2dtc)zX]2(/I-X'2).…”

“…In particular, the proposed mechanism [5] which accounts for the synthesis of these compounds involves as a first step the formation of the corresponding dihalide-bridged dimers, [Fe(R2dtc)zX]2(/I-X'2). Analogous iron(Ill) complexes have already been isolated and their structures were established on the basis of spectroscopic [1, 3,4] and X-ray crystal structure [6] determination methods, as well as the results of thermoanalytical studies [7].…”

Thermal decomposition of some homobinuclear dihalide-bridged iron(III) complexes

“…The apparent activation energies were determined by graphical methods and the TTN temperatures were calculated from the TG profiles. Finally, a possible mechanism of the decomposition is suggested on the basis of the pyrolysis and mass spectral data.In previous papers, results have been reported on the reactions of molecular halogens (X~) with the square-pyramidal complexes [Fe(S2CNR2)2X] (X = CI, Br, I) [1][2][3]. The salient feature of these reactions is the effect of the alkyl substituent in the dithiocarbamato ligand on the composition of the products obtained [4,5].…”

“…The salient feature of these reactions is the effect of the alkyl substituent in the dithiocarbamato ligand on the composition of the products obtained [4,5]. In this respect, a general mechanism accounting for the variety of products formed has been proposed [3].In this paper, we focus our attention on the binuclear iron(Ill) complexes formulated [2] as [Fe(S2CNR2)2X]2(/~-X~), where R = Me, Et, pri; X' = Br, I. M6ssbauer and magnetic measurements on this very interesting class of compounds, as well as an X-ray crystal structure determination [6] of another derivative of this series containing the pyrrolidinyldithiocarbamato ligand, have established the presence of the molecular halogen in the form of a bridging unit mediating the formation of weakly coupled dimers with antiferromagnetic interaction. In particular, the molecular halogen interacts weakly in an end-on fashion with the halide ligand of the mononuclear complexes, forming an extended tetratomic bridging unit, {X-X'-X'-X} 2-, between the two paramagnetic centres.…”