32843-51-9Relevant articles and documents
2-as a Conduit of Electronic Effects: Comparative Studies of Fe···Fe Communication in [{(η5-Cp)(dppe)Fe}2{μ2-(NC-X-CN)}]n+(n = 0, 2)
Guschlbauer, Jannick,Shaughnessy, Kevin H.,Pietrzak, Anna,Chung, Min-Chul,Sponsler, Michael B.,Kaszyński, Piotr
, p. 2504 - 2515 (2021)
Electronic communication between Fe centers in the diiron complexes [{(η5-Cp)(dppe)Fe}2{μ2-(NC-X-CN)}]n+ (n = 0, 2) in which X = [-B10H8-]2-,-C6H4-,-C8H12-, and-C2B10H10-was investigated by spectroscopic (UV-vis and IR), electrochemical (CV and DPV), and single-crystal XRD methods. All experimental results were supported by a DFT computational analysis (B3LYP/Def2SVP) of model complexes that included two other closo-boranes: X =-C2B8H8-and [-B12H10-]2-. The DFT analysis focused on the geometry, electronic excitations, IR spectra, charge and spin delocalization, and intramolecular spin-spin exchange interactions in the series of all six complexes and their singly and doubly oxidized analogues. The results demonstrate that [closo-B10H8-1,10-diyl]2- has the best ability among the closo-boranes to mediate electronic effects similar to those of 1,4-phenylene. This is evident from the observed separation of one-electron-oxidation waves (a 70 mV) and comparable S-T energy gaps in the doubly oxidized species.
Synthesis and characterisation of halide, separated ion pair, and hydride cyclopentadienyl iron bis(diphenylphosphino)ethane derivatives
Patel, Dipti,Wooles, Ashley,Cornish, Andrew D.,Steven, Lindsey,Davies, E. Stephen,Evans, David J.,McMaster, Jonathan,Lewis, William,Blake, Alexander J.,Liddle, Stephen T.
, p. 14159 - 14177 (2015/08/18)
Treatment of anhydrous FeX2 (X = Cl, Br, I) with one equivalent of bis(diphenylphosphino)ethane (dppe) in refluxing THF afforded analytically pure white (X = Cl), light green (X = Br), and yellow (X = I) [FeX2(dppe)]n (X = Cl, I; Br, II; I, III). Complexes I-III are excellent synthons from which to prepare a range of cyclopentadienyl derivatives. Specifically, treatment of I-III with alkali metal salts of C5H5 (Cp, series 1), C5Me5 (Cp, series 2), C5H4SiMe3 (Cp′, series 3), C5H3(SiMe3)2 (Cp′′, series 4), and C5H3(But)2 (Cptt, series 5) afforded [Fe(Cp?)(Cl)(dppe)] 1Cl-5Cl, [Fe(Cp?)(Br)(dppe)] 1Br-5Br, and [Fe(Cp?)(I)(dppe)] 1I-5I (Cp? = Cp, Cp, Cp′, Cp′′, or Cptt). Dissolution of 1I-5I in acetonitrile, or treatment of 1Cl-5Cl with Me3SiI in acetonitrile (no halide exchange reactions were observed in other solvents) afforded the separated ion pair complexes [Fe(Cp?)(NCMe)(dppe)][I] 1SIP-5SIP. Attempts to reduce 1Cl-5Cl, 1Br-5Br, and 1I-5I with a variety of reductants (Li-Cs, KC8, Na/Hg) were unsuccessful. Treatment of 1Cl-5Cl with LiAlH4 gave the hydride derivatives [Fe(Cp?)(H)(dppe)] 1H-5H. This report provides a systematic account of reliable methods of preparing these complexes which may find utility in molecular wire and metal-metal bond chemistries. The complexes reported herein have been characterised by X-ray diffraction, NMR, IR, UV/Vis, and M?ssbauer spectroscopies, cyclic voltammetry, density functional theory calculations, and elemental analyses, which have enabled us to elucidate the electronic structure of the complexes and probe the variation of iron redox properties as a function of varying the cyclopentadienyl or halide ligand.
The intriguing substitution behavior of CO with bidentate phosphine ligands induced by a gem-dialkyl effect
Van Rijn, Jimmy A.,Gouré, Eric,Siegler, Maxime A.,Spek, Anthony L.,Drent, Eite,Bouwman, Elisabeth
, p. 1899 - 1903 (2011/06/19)
The reaction of the complexes [FeCpX(CO)2] (X = Cl, Br, I) into either [FeCp(CO)(PP)]X or [FeCpX(PP)] (PP = a bidentate diphosphine ligand) is shown to be highly dependent of the phosphine ligand used. Diphosphine ligands that form stable chelates favor formation of the neutral complex, whereas diphosphine ligands that form less stable chelates favor formation of the cationic complex. Thus, with the use of dppdmp (= 1,3-bis(diphenylphosphino)-2, 2-dimethylpropane) the [FeCpX(PP)] complexes (X = Cl, Br, I) are selectively formed, induced by a gem-dialkyl effect. Apart from the bidentate phosphine ligand, the halide ion present in the iron complex has a significant influence on the course of the substitution reaction.
