Electrochemical studies on organometallic compounds

Fakhr, A.; Mugnier, Yves; Gautheron, B.; Laviron, E.

doi:10.1016/0022-328x(86)80070-5

Cited by 15 publications

(10 citation statements)

References 27 publications

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“…The reduction of these compounds occurs at -1.26, -2.07, and -2.37 V for Ti, Zr, and Hf, respectively. 57 For both Zr and Hf, it has been demonstrated that this reduction is reversible at low temperatures, 58 whereas at higher temperatures the chloride dissociates quickly and the voltammetry wave is characteristic of an EC mechanism. 59 Attempts to isolate the reduced species 2-Mfollowing treatment of 2-M with simple reactants (e.g., KC 8 , Na/Hg) were not successful.…”

Section: Cyclic Voltammetrymentioning

confidence: 99%

Preparation and physical properties of early-late heterobimetallic compounds featuring Ir–M bonds (M = Ti, Zr, Hf)

2012

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Treatment of Cp*Ir N(t)Bu (1) with the appropriate metallocene equivalent is an effective route for the preparation of the heterobimetallic complexes Cp*Ir(μ-N(t)Bu)MCp(2) (2-M, M = Ti, Zr, Hf). The electronic structures of the isostructural series of compounds, 2-M, are described with reference to single-crystal X-ray, Raman, UV-vis, and cyclic voltammetry data. Density functional theory (DFT) calculations were used to aid in the interpretation of this experimental work. Treatment of the zirconium or hafnium congeners with 2,6-lutidinium triflate leads to protonation of the Ir-M bond, to afford Cp*Ir(μ-N(t)Bu)(μ-H)MCp(2)OTf (3-M, M = Zr, Hf). Compound 3-Zr was characterized by single-crystal X-ray diffraction and independently prepared by the reaction of 1 and Cp(2)Zr(H)Cl in the presence of Me(3)SiOTf. In reactions analogous to those for 2-Zr, 2-Hf reacts with S(8) and aryl azides to insert an S-atom or aryl azide fragment into the metal-metal bond, yielding Cp*Ir(μ-N(t)Bu)(μ-S)HfCp(2) (6-Hf) and Cp*Ir(μ-N(t)Bu)(N(3)Ph)HfCp(2) (4-Hf), respectively. Heating 4-Hf results in N(2) extrusion to form Cp*Ir(μ-N(t)Bu)(NPh)HfCp(2) (5-Hf). The kinetics of the latter reaction were studied to obtain activation parameters and a Hammett trend; these data are compared to those for the analogous reaction involving Ir-Zr heterobimetallics.

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Section: Cyclic Voltammetrymentioning

confidence: 99%

Preparation and physical properties of early-late heterobimetallic compounds featuring Ir–M bonds (M = Ti, Zr, Hf)

2012

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“…The electrochemical behaviour of ansa-titanocene dichlorides [{R(η 5 -C 5 H 4 ) 2 }TiCl 2 ] (R is a bridging group) and substituted bent titanocenes has been studied extensively by a number of research groups. For example, in the methyl substituted bent zirconocenes [(η 5 -C 5 H 5-n Me n ) 2 ZrCl 2 ] (n = 0-4) and titanocenes [(η 5 -C 5 H 5-n Me n ) 2 TiCl 2 ] (n = 0-3) standard reduction potentials were shown to shift negatively with increasing the substituent number by 0.071 and 0.093 V per one methyl substituent, respectively 36,37 . Here the effect of breakdown of the linear potential dependence for [(η 5 -C 5 Me 5 ) 2 ZrCl 2 ] has been assigned to bulkiness of the two ancillary ligands C 5 Me 5 (ref.…”

Section: Metallocene Dichloridesmentioning

confidence: 97%

“…Specifically, single-crystal asymmetric units of isostructural complexes [PhInd 2 MCl 2 ] (M = Zr, Hf) incorporate two rotational isomers (syn and anti) relative to the metal-π-ligand bond 35,36 . Both isomers undergo redox reactions at the same potential within the accuracy of the measurements (±0.01 V).…”

Section: Metallocene Dichloridesmentioning

confidence: 99%

“…We have further revealed electron-transfer induced transformation in other bent zirconium(IV) and hafnium(IV) complexes. Thus, the metastable species [PhInd 2 M II ] (PhInd = η 5 -(2-phenyl)-indenyl) were generated via two successive electron additions and elimination of two chloride ligands from the zirconium(IV) and hafnium(IV) dichlorides [(PhInd) 2 MCl 2 ] (refs 35,36 ). The correctness of the assignment was additionally supported by linear dependence of the E 0 (or E p ) values for the redox couples [PhInd 2 Ni] +/0/-(see refs 34,35 ) and [PhInd 2 M] 0/-(M = Zr, Hf) on ionisation potentials of a corresponding metal (IP j ) in gas phase, viz.…”

Section: Metallocene Dichloridesmentioning

confidence: 99%

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A Review on Molecular Electrochemistry of Metallocene Dichloride and Dimethyl Complexes of Group 4 Metals: Redox Properties and Relation with Optical Ligand-to-Metal Charge Transfer Transitions

Loukova

Strelets

2001

Collect. Czech. Chem. Commun.

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Emphasis is given to redox, photophysical, and photochemical properties of homologous bent metallocenes of group 4 transition metals. Comparative analysis of a variety of electron-transfer induced transformations and ligand-to-metal charge-transfer excited states is performed for bent metallocene complexes upon systematic variation of the identity of the metal ion (Ti, Zr or Hf), ancillary π- and monodentate σ- (Cl, Me) ligands. For such organometallic π-complexes, linear correlations exist between energies of optical and redox HOMO-to-LUMO electron transitions. It is suggested that combination of spectroscopic and electrochemical techniques provides important diagnostics to determine "ionisation potential" and "electron affinity" in solution (relative energies of frontier molecular orbitals obtained as redox potentials) and the energy gap in metallocene complexes. Some of earlier instructive cases of direct relationship between optical transition energies and differences in redox potentials revealed for inorganic and coordination compounds are discussed.

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“…Partial recrystallization from the toluene/hexane mixture affords the precipitation of a yellow powdery material that was found to be paramagnetic (signal centered at 3360 G and DH = 12 G, with a g value of 2.0017), characteristic for a Hf(III) complex. 96 One of the most fascinating questions in the formation of the Hf(III) complex is the…”

Section: Synthesis Of Bis(benzamidinate) Hafnium Dichloride (19)mentioning

confidence: 99%

Design of organometallic group iv heteroallylic complexes and their catalytic properties for polymerizations and olefin centered transformations

Smolensky¹,

Eisen²

2007

Dalton Trans.

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The use of metallocenes in many stoichiometric and catalytic processes has been the impetus for the development of new organometallic complexes, especially those containing early transition metals. The formation of coordinative unsaturated complexes using allylic, benzamidinate and aminopyridine families is presented. The synthesis and structural parameters of the new complexes, their activation and use in the polymerization of alpha-olefins and dienes, in the dehydrogenative coupling of silanes and in the hydroamination reactions comprise the objectives of this review.

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Electrochemical studies on organometallic compounds

Cited by 15 publications

References 27 publications

Preparation and physical properties of early-late heterobimetallic compounds featuring Ir–M bonds (M = Ti, Zr, Hf)

Preparation and physical properties of early-late heterobimetallic compounds featuring Ir–M bonds (M = Ti, Zr, Hf)

A Review on Molecular Electrochemistry of Metallocene Dichloride and Dimethyl Complexes of Group 4 Metals: Redox Properties and Relation with Optical Ligand-to-Metal Charge Transfer Transitions

Design of organometallic group iv heteroallylic complexes and their catalytic properties for polymerizations and olefin centered transformations

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