Reduction of 2-(N,N-dimethylamino)ethyl substituted zirconocene dichlorides: Intramolecular activation of NCH2–H bond. The crystal structures of [η5:η2(C,N)-C5(CH3)4CH2CH2N(CH3)CH2][η5-C5(CH3)5]ZrX (X=Cl, H)

Krut’ko, D. P.; Borzov, Maxim V.; Kirsanov, Roman S.; Churakov, Andrei V.; Кузьмина, Л. Г.

doi:10.1016/j.jorganchem.2005.03.055

Cited by 10 publications

(4 citation statements)

References 24 publications

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“…The reaction is complete in a few hours at room temperature. All the NMR data of the final complex are consistent with the general formula [Cp 2 Zr(η 2 -CH 2 NMeC 16 H 33 ) + ···MeB(C 6 F 5 ) 3 − ] ( Zr NC16 BN ; Scheme ) . In the complex Zr NC16 BN the resonances due to Cp rings (δ H 5.26 and 5.24 ppm) and methylene hydrogen atoms of both the N−CH 2 −R (δ H 2.43 and 2.04 ppm) and Zr−CH 2 −N groups (δ H 1.68 and 1.37 ppm, 2 J HH = 8.4 Hz) are not magnetically equivalent.…”

Section: Resultssupporting

confidence: 71%

Synthesis, Characterization, Interionic Structure, and Self-Aggregation Tendency of Zirconaaziridinium Salts Bearing Long Alkyl Chains

et al. 2010

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Zirconaaziridinium inner sphere ion pairs (ISIPs) bearing alkyl chains of different lengths, [Cp2Zr(eta(2)-(CH2NRR2)-R-1)(+)center dot center dot center dot X-] (R-1 = Me, R-2 = C2H5, X- = MeB(C6F5)(3)(-), (ZrBN)-B-NC2; R-1 = me, R-2 = C16H33, X- = MeB(C6F5)(3)(-), (ZrBN)-B-NC16; R-1 = R-2 = C18H37, X- = MeB(C6F5)(3)(-), (ZrBN)-B-NC18; R-1 = Me, R-2 = Ph, X- = MeB(C6F5)(3)(-), (ZrBN)-B-NPh; R-1 = R-2 = C18H37, X- = B(C6F5)(4)(-), (ZrBT)-B-NC18; R-1 = Me, R-2 = Ph, X- = B(C6F5)(4)(-), (ZrBT)-B-NPh), have been synthesized by the reaction of [Cp2ZrMe+center dot center dot center dot MeB(C6F5)(3)(-)] or [CP2ZrMe+center dot center dot center dot B(C6F5)(4)(-)] with the suitable tertiary amine followed by selective C-H activation of one Me group of the coordinated amine and methane elimination. Subsequent reaction of ISIPs with THF afforded the corresponding outer-sphere ion pairs (OSIPs) ([(ZrTHF)-T-NC2][BN], [(ZrTHF)-T-NC16][BN], [(ZrTHF)-T-NC18][BN], [(ZrTHF)-T-NPh][BN], [(ZrTHF)-T-NC18][BT], [(ZrTHF)-T-NPh][BT]) in which the anion has been displaced into the second coordination sphere. The interionic structure in solution (i.e., the relative cation-anion position) and the self-aggregation level of both ISIPs and OSIPs have been investigated by means of H-1 NOESY, F-19, H-1 HOESY, and diffusion PGSE NMR methods, in low polar solvents. It is found that, independent of the nature or length of the alkyl chains, the anion prefers to pair with the cation from the side of the nitrogen atom and THF in ISIPs and OSIPs, respectively. Self-aggregation of ion pairs into higher aggregates is also weakly influenced by the nature of the alkyl chains, but it is strictly connected with the nature of the counterion: ISIPs and OSIPs bearing B(C6F5)(4)(-) showed an increased tendency to form higher aggregates with respect to those containing MeB(C6F5)(3)(-). The level of the self-aggregation in benzene-d(6) and cyclohexane-d(12) has been quantified by fitting the hydrodynamic volumes obtained from NMR diffusion experiments with several models of indefinite self-association. The IK model, in which the equilibrium constants slightly increase on increasing the aggregation step, best describes the experimental trends in all cases. The standard Gibbs free energy of self-association at 297 K (Delta G(0)) for (ZrBN)-B-NC18 is -6.7 +/- 0.2 kJ mol(-1) and -12.6 +/- 0.7 kJ mol(-1) in benzene-d(6) and cyclohexane-d(12), respectively. In the same solvents, the values of Delta G(0) are -17.9 +/- 0.5 kJ mol(-1) and -25.0 +/- 0.3 kJ mol(-1) for [(ZrTHF)-T-NC18][BT]. At room temperature, 80% and 4% of [(ZrTHF)-T-NC18][BT]are present in the form of ion pairs in cyclohexane-d(12) at analytical concentrations of 10(-5) and 10(-3) M, respectively. The self-aggregation of [(ZrTHF)-T-NC18][BN] in cyclohexane-d(12) is strongly depressed by increasing the temperature

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Section: Resultssupporting

confidence: 71%

Synthesis, Characterization, Interionic Structure, and Self-Aggregation Tendency of Zirconaaziridinium Salts Bearing Long Alkyl Chains

et al. 2010

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“…This result of the reduction of 6 is unlike to what was observed formerly for [g 5 -C 5 Me 4 CH 2 CH 2 NMe 2 ][g 5 -C 5 Me 5 ]ZrCl 2 [19] and recently for the reduction of decamethylzirconocene dichloride with Mg/Hg in pyridine [20]. In these cases, reduction of the metal center was followed by selective oxidative addition of C-H bond to the Zr-atom (NCH 2 -H and ortho-C-H bond in pyridine molecule, respectively).…”

Section: Synthesis Of Half-sandwich Complexes Of Ti(iv) (4) Andcontrasting

confidence: 96%

Complexes of titanium and zirconium based on [C5Me4CH2-(2-C5H4N)] ligand

Krut’ko

Kirsanov

Белов

et al. 2007

Journal of Organometallic Chemistry

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“…In contrast we observed the reaction proceeds via d 2 Zr(II) intermediate. 1 H and 13 C NMR spectra for [g 5 :g 2 (C,N)-C 5 Me 4 CH 2 -CH 2 N(Me)CH 2 ]ZrH fragment in 7 were similar to those of (g 5 -C 5 Me 5 )[g 5 :g 2 (C,N)-C 5 Me 4 CH 2 CH 2 N(Me)CH 2 ]ZrH (8) [17], including the splitting of CH 2 CH 2 proton multiplets. As in case of 8 [17], in the spectra of 7 through-space spinspin interaction between hydride ligand and the adjacent methyl group of Cp-ring (J HÀZrH = 1.7 Hz, J CÀZrH = 6.5 Hz) was observed.…”

Section: Reduction Of Complexesmentioning

confidence: 69%

“…Recently, we reported the synthesis of closely related complex (g 5 -C 5 Me 5 )[g 5 :g 2 (C,N)-C 5 Me 4 CH 2 CH 2 N(Me)CH 2 ]-ZrH (8) (Scheme 6) [17]. The similar cyclic products of the intramolecular CH-activation of NCH 2 -H bonds have been obtained by Erker and coworkers [18,19] via d 0 Zr(IV) cationic intermediates.…”

Section: Reduction Of Complexesmentioning

confidence: 99%

Novel sandwich complexes of zirconium [C9H5(SiMe3)2](C5Me4R)ZrCl2 (R=CH3, CH2CH2NMe2): Synthesis and reduction behavior

Белов

Kirsanov

Krut’ko

et al. 2008

Journal of Organometallic Chemistry

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Reduction of 2-(N,N-dimethylamino)ethyl substituted zirconocene dichlorides: Intramolecular activation of NCH2–H bond. The crystal structures of [η5:η2(C,N)-C5(CH3)4CH2CH2N(CH3)CH2][η5-C5(CH3)5]ZrX (X=Cl, H)

Cited by 10 publications

References 24 publications

Synthesis, Characterization, Interionic Structure, and Self-Aggregation Tendency of Zirconaaziridinium Salts Bearing Long Alkyl Chains

Synthesis, Characterization, Interionic Structure, and Self-Aggregation Tendency of Zirconaaziridinium Salts Bearing Long Alkyl Chains

Complexes of titanium and zirconium based on [C5Me4CH2-(2-C5H4N)] ligand

Novel sandwich complexes of zirconium [C9H5(SiMe3)2](C5Me4R)ZrCl2 (R=CH3, CH2CH2NMe2): Synthesis and reduction behavior

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