Synthesis, Substitution Kinetics, and Electrochemistry of the First Tetrathiafulvalene-Containing β-Diketonato Complexes of Rhodium(I)

Fourie, Eleanor; Swarts, Jannie C.; Lorcy, Dominique; Bellec, Nathalie

doi:10.1021/ic901676e

Cited by 42 publications

(16 citation statements)

References 42 publications

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“…For comparison, [Rh(norbornadienyl)(phen)] + is a melon-colored solid that absorbs weakly in the visible region (ε ≈ 0.92 × 10 3 M –1 cm –1 at 477 nm). [Rh(1,5-cyclooctadienyl)(phen)] + also displays only weak absorbance in the visible region (ε ≈ 0.81 × 10 3 M –1 cm –1 at 457 nm) . The blue-shifting absorptions across this series of phen complexes match with the π-accepting tendencies of the diolefin ligands.…”

Section: Results and Discussionmentioning

confidence: 89%

Structural and Electrochemical Consequences of [Cp*] Ligand Protonation

et al. 2017

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There are few examples of the isolation of analogous metal complexes bearing [η-Cp*] and [η-Cp*H] (Cp* = pentamethylcyclopentadienyl) complexes within the same metal/ligand framework, despite the relevance of such structures to catalytic applications. Recently, protonation of Cp*Rh(bpy) (bpy = 2,2'-bipyridyl) has been shown to yield a complex bearing the uncommon [η-Cp*H] ligand, rather than generating a [Rh-H] complex. We now report the purification and isolation of this protonated species, as well as characterization of analogous complexes of 1,10-phenanthroline (phen). Specifically, reaction of Cp*Rh(bpy) or Cp*Rh(phen) with 1 equiv of EtNHBr affords rhodium compounds bearing endo-η-pentamethylcyclopentadiene (η-Cp*H) as a ligand. NMR spectroscopy and single-crystal X-ray diffraction studies confirm protonation of the Cp* ligand, rather than formation of metal hydride complexes. Analysis of new structural data and electronic spectra suggests that phen is significantly reduced in Cp*Rh(phen), similar to the case of Cp*Rh(bpy). Backbonding interactions with olefinic motifs are activated by formation of [η-Cp*H]; protonation of [Cp*] stabilizes the low-valent metal center and results in loss of reduced character on the diimine ligands. In accord with these changes in electronic structure, electrochemical studies reveal a distinct manifold of redox processes that are accessible in the [Cp*H] complexes in comparison with their [Cp*] analogues; these processes suggest new applications in catalysis for the complexes bearing endo-η-Cp*H.

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Section: Results and Discussionmentioning

confidence: 89%

Structural and Electrochemical Consequences of [Cp*] Ligand Protonation

et al. 2017

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“…The redox properties of 3a – 3e were determined by cyclic (= CV) and square wave voltammetry (= SV) (Figure 5) in anhydrous dichloromethane solutions containing 1 m M of the analyte 3a – 3e and 0.1 M of [ n Bu 4 N][B(C 6 F 5 ) 4 ] as supporting electrolyte 39–46. The results of the electrochemical studies were obtained at a scan rate of 100 mV · s –1 (Table 3).…”

Section: Resultsmentioning

confidence: 99%

Electronic Tuneable Dynamic and Electrochemical Behavior of N‐(Diferrocenylmethylene)anilines

Saloman

Hildebrandt

Korb

et al. 2015

Zeitschrift anorg allge chemie

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N-(Diferrocenylmethylene)anilines Fc 2 C=N-4-C 6 H 4 -R [3a R = CF 3 ; 3b R = Cl; 3c R = H; 3d R = CH 3 ; 3e R = OCH 3 ; Fc = Fe(η 5 -C 5 H 4 )(η 5 -C 5 H 5 )] with different electron-donating or -withdrawing functionalities were synthesized by a Schiff base reaction of substituted anilines H 2 N-4-C 6 H 4 -R (2a-2e) with diferrocenyl ketone (1). Within variable temperature NMR experiments activation enthalpies between 68.1 and 72.3 kJ·mol -1 for an E/Z exchange reaction of the imines were determined. It could be shown that the inversion barrier depends on the nature of the substituent R. Furthermore, electrochemical measurements were performed, demonstrating that the ferrocenyl units are oxidized separately. The electron density at the nitrogen

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“…15, 17 Recently, it was shown that electroactive units such as 1′,1′′′‐biferrocenyl moieties incorporated into the carbon‐bridge that links the metal termini act as a molecular relay, mediating electron transfer between the two ends of the molecule by hopping processes 18. Simultaneously, efforts were also directed toward the construction of molecular compounds incorporating substituted‐tetrathiafulvalene (TTF) electrophores and the exploration of new properties arising from the mutual d–π interactions within hybrid organic and inorganic components 19–21. Considering the unique properties of some TTF derivatives as organic metals, superconductors, and semiconductors, this promising approach stimulates an increasing number of research works 22…”

Section: Introductionmentioning

confidence: 99%

“…[18] Simultaneously, efforts were also directed toward the construction of molecular compounds incorporating substituted-tetrathiafulvalene (TTF) electrophores and the exploration of new properties arising from the mutual d-p interactions within hybrid organic and inorganic components. [19][20][21] Considering the unique properties of some TTF derivatives as organic metals, superconductors, and semiconductors, this promising approach stimulates an increasing number of research works. [22] In the context of our interest in the construction of molecular circuits incorporating several redox active components, we have previously prepared the new hybrid complexes [Cp*A C H T U N G T R E N N U N G (dppe)FeCC-TTFMe 3 ]A C H T U N G T R E N N U N G [PF 6 ] n (1A C H T U N G T R E N N U N G [PF 6 ] n , n = 0, 1, 2; Cp* = h 5 -C 5 A C H T U N G T R E N N U N G (CH 3 ) 5 , dppe = 1,2-bis(diphenylphosphino)ethane).…”

Section: Introductionmentioning

confidence: 99%

Hybrid Molecular Systems Containing Tetrathiafulvalene and Iron‐Alkynyl Electrophores: Five‐Component Functional Molecules Obtained from CH Bond Activation

Justaud¹,

Gendron²,

Ogyu³

et al. 2013

Chemistry A European J

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Treatment of [Cp*(dppe)Fe-C≡C-TTFMe3] (1) with Ag[PF6] (3 equiv) in DMF provides the binuclear complex [Cp*(dppe)Fe=C=C=TTFMe2 =CH-CH=TTFMe2 =C=C=Fe(dppe)Cp*][PF6]2 (2[PF6 ]2) isolated as a deep-blue powder in 69 % yield. EPR monitoring of the reaction and comparison of the experimental and calculated EPR spectra allowed the identification of the radical salt [Cp*(dppe)Fe=C=C=TTFMe2 =CH][PF6]2 ([1-CH][PF6]) an intermediate of the reaction, which results from the activation of the methyl group attached in vicinal position with respect to the alkynyl-iron on the TTF ligand by the triple oxidation of 1 leading to its deprotonation by the solvent. The dimerization of [1-CH][PF6] through carbon-carbon bond formation provides 2[PF6]2. The cyclic voltammetry (CV) experiments show that 2[PF6]2 is subject to two sequential well-reversible one-electron reductions yielding the complexes 2[PF6] and 2. The CV also shows that further oxidation of 2[PF6]2 generates 2[PF6]n (n=3-6) at the electrode. Treatment of 2[PF6]2 with KOtBu provides 2[PF6] and 2 as stable powders. The salts 2[PF6] and 2[PF6]2 were characterized by XRD. The electronic structures of 2(n+) (n=0-2) were computed. The new complexes were also characterized by NMR, IR, Mössbauer, EPR, UV/Vis and NIR spectroscopies. The data show that the three complexes 2[PF6]n are iron(II) derivatives in the ground state. In the solid state, the dication 2(2+) is diamagnetic and has a bis(allenylidene-iron) structure with one positive charge on each iron building block. In solution, as a result of the thermal motion of the metal-carbon backbone, the triplet excited state becomes thermally accessible and equilibrium takes place between singlet and triplet states. In 2[PF6], the charge and the spin are both symmetrically distributed on the carbon bridge and only moderately on the iron and TTFMe2 electroactive centers.

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Synthesis, Substitution Kinetics, and Electrochemistry of the First Tetrathiafulvalene-Containing β-Diketonato Complexes of Rhodium(I)

Cited by 42 publications

References 42 publications

Structural and Electrochemical Consequences of [Cp*] Ligand Protonation

Structural and Electrochemical Consequences of [Cp*] Ligand Protonation

Electronic Tuneable Dynamic and Electrochemical Behavior of N‐(Diferrocenylmethylene)anilines

Hybrid Molecular Systems Containing Tetrathiafulvalene and Iron‐Alkynyl Electrophores: Five‐Component Functional Molecules Obtained from CH Bond Activation

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