Iron Halide Complexes Research Articles

Germylene-Fe complexes caused by heterometallic coupling and investigation into the 3d-4p bonding

The interpretation of heterometallic bonding nature is a basic work of inorganic chemistry. By means of intermetallic substitution of germylene anions with iron halide complexes CpFe(CO)2I and β-diketiminato FeII chloride, the ferrogermylene complexes 3a, 3b and 4a were synthesized and structurally characterized. The structural and IR characterizations show the presence of the Ge←Fe π backbonding in molecules 3a, 3b and 4a. The computational works on frontier molecular orbitals and their comparison of energy states confirmed that σ donation and π backbonding are both weak in these molecules, despite three complexes have longer Ge-Fe bonds, whose strength decreases slightly with the degressive electron density around Fe environment in a sequence from 3a, 3b to 4a.

γ-valerolactone (GVL) as a bio-based green solvent and ligand for iron-mediated AGET ATRP

AbstractIn this paper, γ-valerolactone (GVL), a bio-based polar solvent, was applied as green solvent for iron(III)-catalyzed AGET ATRP without any external ligand. GVL is a fully degradable, non-toxic green solvent and has complex ability to iron halide complexes through –OCO- group. GVL as the solvent and the ligand for AGET ATRP of MMA in a controlled manner, as proved by kinetic study, the low PDI values and the increase in polymer molecular weight versus monomer conversion. Chain re-initiation experiments and 1HNMR characterization were conducted to further confirm the living feature.

Investigation of formally zerovalent Triphos iron complexes

The reduction of Triphos [PhP(CH(2)CH(2)PPh(2))(2)] iron halide complexes has been explored, yielding formally zerovalent (κ(3)-Triphos)Fe(κ(2)-Triphos) and (κ(3)-Triphos)Fe(κ(2)-Bpy). Electrochemical analysis, coupled with the metrical parameters of (κ(3)-Triphos)Fe(κ(2)-Bpy), reveal an electronic structure consistent with a π-radical monoanion bipyridine chelate that is antiferromagnetically coupled to a low spin, Fe(I) metal center.

Pyridylmethylamines as Ligands in Iron Halide Complexes – Coordination Behaviour Depending on the Halide, the Denticity of the Amino Ligand and the Oxidation State of Iron

Abstract2‐Pyridylmethylamine (amp) and 8‐aminochinoline (ach) readily form the following complexes with iron halides in methanol: [(amp)2FeCl2] (1a), [(amp)2FeBr2] (1b), [(ach)2Fe(MeOH)2]Br2 (1c), and [(amp)FeCl2(μ‐OMe)]2 (2). Methanol was chosen as a solvent because these reactions are rather complex in ether. For example, FeCl3 forms the ionic complex pair [(dme)2FeCl2] [FeCl4] (3) with 1,2‐dimethoxyethane (dme). The reaction of FeBr2 with tridentate di(2‐pyridylmethyl)amine (dpa) and tetradentate 1,2‐dipyridyl‐1,2‐diaminoethane (dpdae) yields the complexes [(dpa)2Fe]Br2·2 MeOH (4) and [(dpdae)2Fe] [FeBr4] (5), respectively. Crystallographic and magnetochemical investigations show the high‐spin configuration for the complexes 1 and 2, whereas the short Fe‐N distances of 4 clearly indicate a low‐spin state. Compound 2 exhibits an antiferromagnetic exchange interaction with a coupling constant J = −29.4 cm−1 (H;af = −J S;afA·S;afB).

New FeII starting materials: preparation, characterisation and structural features of iron halide complexes with alcohol ligands

The new mononuclear [FeCl2(HOPri)4] (1), polymeric [{Cl3Fe(μ-Cl)Fe(HOPri)4}n] (2) and binuclear [I2Fe(μ-I)2Fe(PriOH)4] (3) iron(II) complexes have been synthesized in high yields in propan-2-ol or toluene/propan-2-ol mixtures at room temperature. Magnetic moment measurements, 57Fe Mössbauer spectroscopy data and the results of semi-empirical quantum mechanical calculations confirmed the high-spin configuration of the iron(II) centres, which were shown to be four- and/or six-coordinate by single crystal X-ray diffraction analyses. Intermolecular hydrogen bonding was observed in the solid state structure of 1, intramolecular interactions in 2, while both intra- and intermolecular association was seen in 3. Long iron–(μ-halide) bonds suggest the possibility of complex dissociation in solution and facile ligand substitution in 2 and 3.

Controlled/“Living” Radical Polymerization of Styrene and Methyl Methacrylate Catalyzed by Iron Complexes

Controlled/“living” radical polymerization of styrene and methyl methacrylate has been achieved by atom transfer radical polymerization (ATRP) catalyzed by iron halide complexes under both homogeneous and heterogeneous conditions. A variety of coordinating ligands have been used including 4,4‘-bis(5-nonyl)-2,2‘-bipyridine, trialkylamines, triphenylphosphine, trialkylphosphines, and trialkylphosphites. The polymer number-average molecular weight (Mn) increases linearly with monomer conversion and matches the predicted molecular weight. The polymerization rate and molecular weight distribution (Mw/Mn = 1.1−1.5) are affected by the structure of the coordinating ligands and the monomers employed.

An investigation of some iron halide complexes by Mössbauer spectroscopy

The products of the reaction between iron carbonyls and various ligands have been examined by Mössbauer spectroscopy. With triphenylphosphine and triphenylarsine, complexes of Fe(III) in a tetrahedral configuration are produced. In all other cases the complexes contain Fe(II), and it is suggested that these are not monomeric, but are chlorine bridged complexes.

Reactions of iron carbonyls with various ligands in the presence of chloroform. A new method for the preparation of iron halide complexes

Iron halide complexes of the type FeCl2•2L (L = CH3CONH2, HCONH2, HCONHCH3) and FeCl3•L (L = (C6H5)3P, (C6H5)3As, C6H5NH2, C6H5CONH2) have been prepared by the reaction of iron carbonyls with various ligands in chloroform as solvent. The mechanism of the reaction and the effect of other solvents have also been studied. The magnetic susceptibility measurements and infrared spectral study (4000–200 cm−1) suggest that these complexes have tetrahedral configuration. The possible site of bonding in ligands and infrared assignments for Fe—O, Fe—Cl, Fe—N, Fe—P, Fe—As bands have been given. The relative Fe—O bond strengths in various amide complexes have been determined on the basis of metal–oxygen stretching frequency and of shifts in carbonyl stretching frequency.

The Structure, Spectra, and Magnetic Properties of Certain Iron Halide Complexes

The Structure, Spectra, and Magnetic Properties of Certain Iron Halide Complexes