Investigation of the electrochemical properties of substituted titanocene dichlorides

Johnston, Randy F.; Borjas, Ricardo E.; Furilla, Joan L.

doi:10.1016/0013-4686(94)00313-p

Cited by 16 publications

(7 citation statements)

References 23 publications

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“…Another aim is to describe in detail the mechanism for the reduction of Cp 2 TiX 2 on the basis of cyclic voltammetric and kinetic measurements, in order to elucidate the nature of the different species present in solution. At the same time we will attempt to extract quantitative information from the recorded voltammograms by employing digital simulations and settle a longstanding dispute concerning whether Cp 2 TiCl 2produced from the reduction of Cp 2 TiCl 2 is stable [14][15][16] or dissociates to give Cp 2 TiCl and Cl -. 17,18 Previous electrochemical investigations have been carried out by means of polarography [19][20][21][22][23] and cyclic voltammetry [14][15][16][17][18][24][25][26][27][28][29] in various solvents such as N,N-dimethylformamide, for-Typical cyclic voltammograms of Cp 2 TiX 2 (X ) Cl, Br, I) recorded at a sweep rate of 1 V s -1 are collected in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Investigation of the Electrochemical Reduction of Cp₂TiX₂

et al. 2004

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The mechanism for the electrochemical reduction of titanocene dihalides, Cp 2 TiX 2 (X ) Cl, Br, I), in tetrahydrofuran has been described successfully using a common mesh scheme. On the basis of simulations of recorded cyclic voltammograms it has been possible to evaluate a number of thermodynamic and kinetic parameters for the species involved: i.e., Cp 2 TiX 2 -, (Cp 2 TiX) 2 , Cp 2 TiX, and Cp 2 Ti + . In general, the standard potentials of the oxidized titanium-based species increase (i.e. become less negative) in the orders Cp 2 TiX 2 , (Cp 2 TiX) 2 + , Cp 2 TiX + , CpTi 2+ and X ) Cl, Br, I. From the extracted data pertaining to electrochemically reduced solutions of Cp 2 TiX 2 , it becomes evident that while Cp 2 TiX 2 -is the major constituent for X ) Cl, Cp 2 TiX and (Cp 2 TiX) 2 are the main species in the cases of X ) Br, I. The presence of (Cp 2 TiX) 2 is surprising, as the solvent tetrahydrofuran was believed to be capable of breaking the weak dimeric structure. Kinetic investigations of the reactions between electrochemically reduced solutions of Cp 2 TiX 2 and benzyl chloride show that the reactive species are Cp 2 TiX and (Cp 2 TiX) 2 , with almost no contribution from Cp 2 TiX 2 -, even in the case of X ) Cl.

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Section: Introductionmentioning

confidence: 99%

Mechanistic Investigation of the Electrochemical Reduction of Cp₂TiX₂

et al. 2004

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“…We think that this behavior is due to a temperature dependent redox-equilibrium with the room temperature solution containing a Ti(III) radical anion, according to Scheme 4. Such a redox equilibria are known from electrochemical studies of Cp2TiCl2 [41,42]. It was found that dependent on the cyclopentadienyl ring substituents, the intermediate radical anion might either reversibly split off a chloride anion yielding Cp2TiCl (the so-called "Nugent-Rajanbabu-reagent" [43]) or irreversibly one of the cyclopentadienyl ligands to give CpTiCl2.…”

Section: Discussionmentioning

confidence: 99%

Metalation Studies on Titanocene Dithiolates

Kießling

Sünkel

2018

Inorganics

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Titanocene bis-arylthiolates [(C5H4X)(C5H4Y)Ti(SC6H4R)2] (X,Y = H, Cl; R = H, Me) can be prepared from the corresponding titanocene dichlorides by reacting with the thiols in the presence of DABCO as a base. They react with n-butyl lithium to give unstable Ti(III) radical anions. While the unsubstituted thiolates (X = Y = R = H) react with lithium Di-isopropylamide by decomposing to dimeric fulvalene-bridged and thiolate-bridged Ti(III) compounds, the ring-chlorinated compounds can be deprotonated with LDA and give appropriate electrophiles di-substituted and tri-substituted titanocene dithiolates.

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“…1 H (300 MHz), 13 C (75 MHz) and 19 F (282 MHz) NMR spectra were measured at Varian Mercury 300 in CDCl 3 (conc. 30 mM).…”

Section: Methods Procedures and Instrumentationmentioning

confidence: 99%

“…1 H and 13 C chemical shifts (δ/ppm) are given relative to solvent signals (δ H /δ C : CDCl 3 7.26/77.16). 19 F NMR spectra were referenced to external CFCl 3 .…”

Section: Methods Procedures and Instrumentationmentioning

confidence: 99%

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Electrochemical Study of Highly Substituted Titanocene Dihalides

et al. 2019

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Titanocene dihalides are promising alternative to Cisplatin in cancer chemotherapy which should reduce negative side effects and overcome increasing resistance of cancer cells. Since the mechanism of anti‐cancer action is associated with generation of reactive oxygen species (ROS), hence with redox processes, electrochemical investigation of titanocene species would be an important issue, not applied up to now. In this article we report on the electrochemical reduction as well as oxidation of titanocene difluorides and dichlorides where unsubstituted as well as highly substituted titanocene dihalides are compared. The experiments were realized in acetonitrile using various electrode materials. The studied series was completed by a new dimethylsilylene bridged ansa‐titanocene difluoride which was characterized by NMR and x‐ray crystallography. The influence of structure and substitution on the redox properties was evaluated and, in addition to this, cytotoxicity of studied titanocene dihalides against human ovarian cancer cell lines A2780 and SK‐OV‐3, as well as against human embryonic kidney cell line HEK293 were screened. Two of highly substituted titanocenes exhibit cytotoxicity comparable with that of Cisplatin.

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Investigation of the electrochemical properties of substituted titanocene dichlorides

Cited by 16 publications

References 23 publications

Mechanistic Investigation of the Electrochemical Reduction of Cp₂TiX₂

Mechanistic Investigation of the Electrochemical Reduction of Cp₂TiX₂

Metalation Studies on Titanocene Dithiolates

Electrochemical Study of Highly Substituted Titanocene Dihalides

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Investigation of the electrochemical properties of substituted titanocene dichlorides

Cited by 16 publications

References 23 publications

Mechanistic Investigation of the Electrochemical Reduction of Cp2TiX2

Mechanistic Investigation of the Electrochemical Reduction of Cp2TiX2

Metalation Studies on Titanocene Dithiolates

Electrochemical Study of Highly Substituted Titanocene Dihalides

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Mechanistic Investigation of the Electrochemical Reduction of Cp₂TiX₂

Mechanistic Investigation of the Electrochemical Reduction of Cp₂TiX₂