Molecular properties of a bis(ketoiminato)-bis(tricarbonyliron) complex obtained by symmetric cleavage from acetophenone azine. Idealized symmetry in anti and syn isomers studied by X-ray diffraction, NMR and density functional theory

Zimniak, Andrzej; Bakalarski, Grzegorz

doi:10.1016/s0022-2860(01)00604-4

Cited by 14 publications

(9 citation statements)

References 9 publications

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“…This is likely to result from the strong trans effect of the imide ligands, which destabilizes the complex and causes a high activation barrier as a consequence of the large change in geometry compared to the azine complex. Thus, most probably, direct NN activation is not operative in our systems—in contrast to the reported examples 7–9. Computational investigation of the mechanism is currently under way.…”

Section: Methodsmentioning

confidence: 55%

“…Azine derivatives display important biological properties and are of importance for drug development 6. Complexes of titanium,7 zirconium,7c cobalt,7c uranium,8 and iron9 are capable of cleaving the NN bond in azines. In all the reported cases, the azine NN bond is cleaved symmetrically forming two imide units, NCR 2 , coordinated to a metal center.…”

Section: Methodsmentioning

confidence: 99%

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Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by Rh^I

et al. 2003

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Azines (R 2 C¼NÀN¼CR 2 ) are very useful compounds. For example, they undergo unusual [1,3] dipolar cycloaddition reactions (the crisscross addition) with dienophiles, which provide a convenient route to five-membered rings. [1] They also participate in [3þ2] cycloaddition reactions as an ene fragment. [2] Applications of azines include possible nonlinear optical materials [3] and conducting polymers (polyazines). [4] Relevant to dinitrogen fixation, the formation of azines by metal-mediated functionalization of N 2 was demonstrated. [5] Azine derivatives display important biological properties and are of importance for drug development. [6] Complexes of titanium, [7] zirconium, [7c] cobalt, [7c] uranium, [8] and iron [9] are capable of cleaving the N À N bond in azines. In all the reported cases, the azine NÀN bond is cleaved symmetrically forming two imide units, ÀN¼CR 2 , coordinated to a metal center. No metal-complex-catalyzed reactions were reported. Herein we report a novel type of azine reactivity, the rhodium-promoted catalytic "nonsymmetrical" NÀN bond cleavage accompanied by C À H activation, which leads to an imine and benzonitrile. This is the first metal-promoted nonsymmetric cleavage of the NÀN bond in an azine [10] and the first metal-catalyzed NÀN activation in an azine.When a toluene solution of the PCP-pincer rhodium complex 1 [11] was treated with one equivalent of benzalazine at À30 8C, three complexes were formed (Scheme 1). One of them, tentatively identified by NMR spectroscopy as the [(PCP)Rh(benzalazine)] complex 2 (precedents exist for azine complexes [7] ), is an intermediate, which converts into [*] Prof.

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Section: Methodsmentioning

confidence: 55%

Section: Methodsmentioning

confidence: 99%

Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by Rh^I

et al. 2003

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“…Reactions of azines with W, Ti and Zr are reported to proceed with C–H activation, C–C coupling and N–C cleavage, affording ketimido and five‐membered metallocycle derivatives. Cyclometallation of azine– involving C–Cl and C–F bond activation has been observed with cobalt, and N‐N bond cleavage and N‐N coupling was observed in Rh and Fe complexes. However, the only reported example of ruthenium complexes involves chelation of pyridyl azines as ligands.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Azine Complexes of Ruthenium(II)

et al. 2016

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Aldazine complexes [RuCl(η6-p-cymene){κ1-[N=C(H)R1]-N=C(H)R1}L]BPh4 (1-4) [L=P(OMe)3, P(OEt)3, PPh(OEt)2, PiPr3; R1=Ph, 4-CH3C6H4, 4-CH3OC6H4, Et] were prepared by allowing chloro compounds RuCl2(η6-p-cymene)L to react with the azine R1(H)C=N-N=C(H)R1 in ethanol. Depending on the nature of the phosphine ligand, the reaction of ketazine (CH3)2C=N-N=C(CH3)2 with chloro compounds RuCl2(η6-p-cymene)L yielded either hydrazone derivatives [RuCl(η6-p-cymene){NH2N=C(CH3)2}L]BPh4 (5,6) [L=P(OMe)3, P(OEt)3] or κ1-azine complex [RuCl(η6-p-cymene){κ1-[N=C(CH3)2]N=C(CH3)2}(PiPr3)]BPh4 (7). Cyclopentadienyl derivatives [Ru(η5-C5H5){κ1-[N=C(H)R1]-N=C(H)R1}(PPh3){P(OMe)3}]+ (10) [R1=Ph, 4-CH3C6H4, C2H5] were prepared by reacting the chloro compound RuCl(η5-C5H5)(PPh3)[P(OMe)3] first with AgOTf and then with an excess of azine. Instead, treatment of RuCl(η5-C5H5)(PPh3)[P(OMe)3] first with AgOTf and then with ketazine (CH3)2C=N-N=C(CH3)2 in ethanol, yielded hydrazone derivative [Ru(η5-C5H5){NH2N=C(CH3)2}(PPh3){P(OMe)3}]BPh4 (11). Oxidation of hydrazone derivative 11 with HgO gave dimethyldiazoalkane complex [Ru(η5-C5H5){N2C(CH3)2}(PPh3){P(OMe)3}]BPh4 (13). The complexes were characterised by spectroscopy and X-ray crystal structure determination of [RuCl(η6-p-cymene){κ1-[N=C(H)Ph]-N=C(H)Ph}{P(OMe)3}]BPh4 (1 a), [RuCl(η6-p-cymene){κ1-[N=C(H)Ph]-N=C(H)Ph}{P(OEt)3}]BPh4 (2 a) and [Ru(η5-C5H5){NH2N=C(CH3)2}(PPh3){P(OMe)3}]BPh4 (11)

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“…[5] Azine derivatives display important biological properties and are of importance for drug development. [6] Complexes of titanium, [7] zirconium, [7c] cobalt, [7c] uranium, [8] and iron [9] are capable of cleaving the N À N bond in azines. In all the reported cases, the azine NÀN bond is cleaved symmetrically forming two imide units, ÀN¼CR 2 , coordinated to a metal center.…”

mentioning

confidence: 99%

“…Thus, most probably, direct NÀN activation is not operative in our systems-in contrast to the reported examples. [7][8][9] Computational investigation of the mechanism is currently under way.…”

mentioning

confidence: 99%

Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by Rh^I

et al. 2003

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Molecular properties of a bis(ketoiminato)-bis(tricarbonyliron) complex obtained by symmetric cleavage from acetophenone azine. Idealized symmetry in anti and syn isomers studied by X-ray diffraction, NMR and density functional theory

Cited by 14 publications

References 9 publications

Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by Rh^I

Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by Rh^I

Preparation of Azine Complexes of Ruthenium(II)

Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by Rh^I

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Molecular properties of a bis(ketoiminato)-bis(tricarbonyliron) complex obtained by symmetric cleavage from acetophenone azine. Idealized symmetry in anti and syn isomers studied by X-ray diffraction, NMR and density functional theory

Cited by 14 publications

References 9 publications

Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by RhI

Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by RhI

Preparation of Azine Complexes of Ruthenium(II)

Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by RhI

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Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by Rh^I

Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by Rh^I

Novel Azine Reactivity: Facile NN Bond Cleavage, CH Activation, and NN Coupling Mediated by Rh^I