η2-Iminoacylmetallocen-substituierte Ylide durch Isonitril-Insertion in die -Bindung von Zirconocen-und Hafnocenyliden Cp2M(R)CHPPh3

Erker, Gerhard; Korek, Uwe; Petersen, Jeffrey L.

doi:10.1016/0022-328x(88)89016-8

Cited by 20 publications

(6 citation statements)

References 58 publications

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“…The structural parameters, such as the C=N distance and the internal angles within the three-membered ZrCN rings, are consistent with those reported for other organozirconium compounds containing one, two, or three 19 η 2 -iminoacyl ligands. Normally, one finds that for these Zr η 2 -iminoacyl complexes, the Zr−N bond distance is typically equal to or less than the Zr−C bond distance within the same η 2 -iminoacyl ligand.…”

Section: Discussion Of Resultssupporting

confidence: 87%

Double Isocyanide Insertion and C,C-Coupling Reaction of [(C₅Me₄)SiMe₂(N-t-Bu)]ZrMe₂. Structural Characterization of the Two 1,4-Diaza-5-zirconacyclopentene Ring Conformations for [(C₅Me₄)SiMe₂(N-t-Bu)]Zr[N(R)C(Me)C(Me)N(R)] Complexes

Kloppenburg

Petersen

1997

Organometallics

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The reactions of 2 equiv of CNR (R = (a) tert-butyl, (b) 2,6-xylyl, (c) Me) with [(C5Me4)SiMe2(N-t-Bu)]ZrMe2, 1, proceed sequentially with isocyanide insertion into both Zr−C(methyl) bonds of this 14-electron complex to give the corresponding η2-iminoacyl Zr complexes [(C5Me4)SiMe2(N-t-Bu)]ZrMe[η2-C(Me)NR], 2, and [(C5Me4)SiMe2(N-t-Bu)]Zr[η2-C(Me)NR]2, 3. Subsequent thermolysis of 3 leads to C,C-coupling of the two η2-iminoacyl units and proceeds solely with formation of the enediamidate 4. Compounds 2a, 3a−c, and 4a−c have been observed and characterized by solution NMR measurements, and the molecular structures of 3a, 3b, 4a, and 4b have been confirmed by crystallographic methods. The nonplanar 1,4-diaza-5-zirconacyclopentene rings of 4a and 4b are folded by ca. 50° in opposite directions along the corresponding N···N line segment and adopt the prone and supine conformations, respectively. The activation parameters for the first-order intramolecular C,C-coupling reaction leading to the conversion of 3a → 4a are ΔH ⧧ = 24.6(2) kcal/mol and ΔS ⧧ = −11.3(7) eu and of 3b → 4b are ΔH ⧧ = 23.9(3) kcal/mol and ΔS ⧧ = −10.4(8) eu.

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Section: Discussion Of Resultssupporting

confidence: 87%

Double Isocyanide Insertion and C,C-Coupling Reaction of [(C₅Me₄)SiMe₂(N-t-Bu)]ZrMe₂. Structural Characterization of the Two 1,4-Diaza-5-zirconacyclopentene Ring Conformations for [(C₅Me₄)SiMe₂(N-t-Bu)]Zr[N(R)C(Me)C(Me)N(R)] Complexes

Kloppenburg

Petersen

1997

Organometallics

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“…An odd numbered, symmetrical multiplet of low intensity at δ 240.0 for 3a and a singlet at δ 239.7 for 3b are consistent with the presence of η 2 -iminoacyl fragments in 3a and 3b . 18b,, The ν(CN) stretching mode is observed at 1618 cm -1 for 3a and at 1625 cm -1 for 3c . Literature values for similar compounds range from 1490 to 1760 cm -1 . − …”

Section: Resultsmentioning

confidence: 99%

Novel Metallacycles via Nucleophilic Aminomethylation: 5,5-Bis(cyclopentadienyl)-1,3-diaza-5-zirconacyclohexane and Related Organometallic Heterocycles

1998

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The doubly lithiated aminals bis(lithiomethyl(methylamino))methane [LiCH2N(Me)]2CH2 (1a) and bis(lithiomethyl-isopropylamino)methane [LiCH2N(i-Pr)]2CH2 (1b) react with Cp- and Cp*- (Cp* = C5Me5) substituted zirconocene chlorides in toluene to give (2a, R = Me; 2c, R = i-Pr) and (2b, R = Me; 2d, R = i-Pr). An interaction of the nitrogen atoms of the metallacycles with the zirconium centers in the solid state (2a, 2b) and in solution (2a, 2c) is deduced from structural studies and from the 1H NMR spectra at variable temperatures (ΔG ⧧ = 65.7 ± 0.6 kJ mol-1 for the ring inversion process in 2c). Isonitriles CNR (R = t-Bu, Me) and CO insert in one of the zirconium methylene σ-bonds of 2b and 2d and yield (3a, R1 = Me, R2 = t-Bu; 3b, R1 = i-Pr, R2 = t-Bu; 3c, R1, R2 = Me) and the zirconium enolates (4a, R = Me; 4b, R = i-Pr), respectively. Further insertion of isonitriles does not occur. Complexes 2a and 2c are unaffected by isonitriles or CO. The molecular structures of 2a, 2b, and 3a have been studied by X-ray diffraction. The resulting structural information of the complexes 2a and 2b provides valuable insight into the nature of the Zr ← N interaction within the metallacycles, which is discussed briefly.

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“…The migratory insertion of organic isocyanides (RNC) into early transition metal−alkyl, −hydride, −silyl, −amido, and −phosphido bonds is an important reaction in organometallic chemistry that has received considerable study over the last 25 years. , The insertion chemistry of RNC with cationic group 4 transition metal systems has also recently received attention . Much of this interest has stemmed from the importance of relating this chemistry to the isoelectronic carbon monoxide (CO) molecule.…”

Section: Introductionmentioning

confidence: 99%

Reactivity of Group 4 Metal Alkyl and Metallacyclic Compounds Supported by Aryloxide Ligands Toward Organic Isocyanides

1999

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The reactivity of the dimethyl compound [Ti(OC6H3Ph2-2,6)2Me2] (1) and titanabicyclic compounds [(ArO)2Ti(CH2CH(C4H8)CHCH2)] (6, 7) (formed by trans-coupling of 1,7-octadiene) toward organic isocyanides has been investigated. Dimethyl 1 reacts with 1 equiv of 2,6-dimethylphenylisocyanide (xyNC) to produce a cyclometalated product [Ti(OC6H3Ph2-2,6)(OC6H3Ph-η1-C6H4){N(xy)CHMe2}] (2), which was structurally characterized. Compound 2 is believed to arise via CH bond activation within an intermediate η2-imine (azatitanacyclopropane) formed by transfer of both methyl groups to the isocyanide. With an excess of xyNC, 1 produces an intermediate bis(η2-iminoacyl) 4, which slowly converts to the enediamide [Ti(OC6H3Ph2-2,6)2{N(xy)CMeCMeN(xy)}] (5). The solid-state structure of 5 shows the presence of a folded diazatitanacyclopent-3-ene ring formed by intramolecular coupling of the two iminoacyl groups. Titanabicyclic compounds 6 and 7 react with ButNC and xyNC respectively to generate products 8 and 9, which both contain amide ligands derived by CH bond activation and an iminoacyl group formed by insertion into the new Ti−C bond. The solid-state structure of [Ti(OC6H3Ph2-2,6){OC6H3Ph-(η2-(C6H4)CNBut)}{ButNCH(C8H14)}] (8) shows a trans-fusion between the five- and six-membered carbon rings as found in the initial titanabicycle 6. The treatment of 1 with xyNC in the presence of excess 3-hexyne or styrene produces azatitanacyclopent-2-ene 10 and azatitanacyclopentane 11 derivatives, respectively. These arise via coupling of the alkyne or olefin with an intermediate η2-imine. The solid-state structure of [Ti(OC6H3Ph2-2,6)2{N(xy)C(Me2)C(Et)C(Et)}] (10) confirms its formulation.

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η2-Iminoacylmetallocen-substituierte Ylide durch Isonitril-Insertion in die -Bindung von Zirconocen-und Hafnocenyliden Cp2M(R)CHPPh3

Cited by 20 publications

References 58 publications

Double Isocyanide Insertion and C,C-Coupling Reaction of [(C₅Me₄)SiMe₂(N-t-Bu)]ZrMe₂. Structural Characterization of the Two 1,4-Diaza-5-zirconacyclopentene Ring Conformations for [(C₅Me₄)SiMe₂(N-t-Bu)]Zr[N(R)C(Me)C(Me)N(R)] Complexes

Double Isocyanide Insertion and C,C-Coupling Reaction of [(C₅Me₄)SiMe₂(N-t-Bu)]ZrMe₂. Structural Characterization of the Two 1,4-Diaza-5-zirconacyclopentene Ring Conformations for [(C₅Me₄)SiMe₂(N-t-Bu)]Zr[N(R)C(Me)C(Me)N(R)] Complexes

Novel Metallacycles via Nucleophilic Aminomethylation: 5,5-Bis(cyclopentadienyl)-1,3-diaza-5-zirconacyclohexane and Related Organometallic Heterocycles

Reactivity of Group 4 Metal Alkyl and Metallacyclic Compounds Supported by Aryloxide Ligands Toward Organic Isocyanides

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η2-Iminoacylmetallocen-substituierte Ylide durch Isonitril-Insertion in die -Bindung von Zirconocen-und Hafnocenyliden Cp2M(R)CHPPh3

Cited by 20 publications

References 58 publications

Double Isocyanide Insertion and C,C-Coupling Reaction of [(C5Me4)SiMe2(N-t-Bu)]ZrMe2. Structural Characterization of the Two 1,4-Diaza-5-zirconacyclopentene Ring Conformations for [(C5Me4)SiMe2(N-t-Bu)]Zr[N(R)C(Me)C(Me)N(R)] Complexes

Double Isocyanide Insertion and C,C-Coupling Reaction of [(C5Me4)SiMe2(N-t-Bu)]ZrMe2. Structural Characterization of the Two 1,4-Diaza-5-zirconacyclopentene Ring Conformations for [(C5Me4)SiMe2(N-t-Bu)]Zr[N(R)C(Me)C(Me)N(R)] Complexes

Novel Metallacycles via Nucleophilic Aminomethylation: 5,5-Bis(cyclopentadienyl)-1,3-diaza-5-zirconacyclohexane and Related Organometallic Heterocycles

Reactivity of Group 4 Metal Alkyl and Metallacyclic Compounds Supported by Aryloxide Ligands Toward Organic Isocyanides

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Double Isocyanide Insertion and C,C-Coupling Reaction of [(C₅Me₄)SiMe₂(N-t-Bu)]ZrMe₂. Structural Characterization of the Two 1,4-Diaza-5-zirconacyclopentene Ring Conformations for [(C₅Me₄)SiMe₂(N-t-Bu)]Zr[N(R)C(Me)C(Me)N(R)] Complexes

Double Isocyanide Insertion and C,C-Coupling Reaction of [(C₅Me₄)SiMe₂(N-t-Bu)]ZrMe₂. Structural Characterization of the Two 1,4-Diaza-5-zirconacyclopentene Ring Conformations for [(C₅Me₄)SiMe₂(N-t-Bu)]Zr[N(R)C(Me)C(Me)N(R)] Complexes