Spaltung der NN-bindung von diazirinen durch Ru3(CO)12

Mastropasqua, P.; Riemer, A.; Kisch, Horst

doi:10.1016/s0022-328x(00)90998-7

Cited by 21 publications

(1 citation statement)

References 4 publications

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“…Relatively few examples exist of similar insertions into metal imido bonds to form isocyanates, despite the fact that this reaction is believed to be involved in the catalytic carbonylation of organoazides and nitroaromatic compounds , Much work has been focused on the interaction of diazenes with titanium complexes .…”

Section: Discussionmentioning

confidence: 99%

Synthesis, Structure, and Reactivity of η²-N₂-Aryldiazoalkane Titanium Complexes: Cleavage of the N−N Bond

et al. 1998

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A series of η2-N2-titanium aryldiazoalkane complexes Cp*2Ti(N2CHAr) (5−10), where Ar is a para-substituted aryl group, have been prepared by addition of aryldiazoalkanes to Cp*2Ti(C2H4) (4). Unlike most diazoalkane complexes, they release dinitrogen thermally to give transient carbene complexes which may be trapped with styrene to form the titanacyclobutane complexes Cp*2Ti(CHArCHPhCH2) (11−15). The kinetics of these reactions in toluene-d 8 at 78.0 °C have been examined by 1H NMR spectroscopy. A Hammett analysis (ρ = − 0.26) indicated that the reaction is relatively insensitive to para-substituents on the aromatic ring of the diazoalkane ligand, but application of the E- and C-based dual parameter substituent constant analysis suggests that this may be due to almost exactly compensating covalent and electrostatic contributions of each substituent to the reaction rate. The stability of the aryldiazoalkane complexes at temperatures below 75 °C allows their reactivity to be explored without competitive N2 loss. The addition of tBuNC results in a coordination change of the diazoalkane fragment from η2 to η1 to give Cp*2Ti(η1-N2CHPh)(tBuNC) (16), as shown by 15N NMR chemical shifts and N−H coupling constants. The bound tBuNC ligand exchanges with free tBuNC in solution, as established by an EXSY experiment. Trineopentylaluminum coordinates to the terminal nitrogen atom on the diazoalkane fragment to form Cp*2TiN(AlNp3)N(C(H)C6H4Me) (17), as determined by X-ray crystallography. Silanes (HSiR3; R3 = PhH2, Ph2H) add across the Ti−N bond of Cp*2Ti(N2C(H)C6H4Me) to give (E)-Cp*2Ti(H)(N(SiR3)(NC(H)C6H4Me) ((E)-19, (E)-20), the kinetic product and (Z)-Cp*2Ti(H)(N(SiR3)(NC(H)C6H4Me) ((Z)-19, (Z)-20), the thermodynamic product. Diazoalkane adduct Cp*2Ti(N2C(H)C6H4Me) undergoes N−N bond cleavage when treated with CO to form an alkylideneimido isocyanato complex Cp*2Ti(NCO)NC(H)C6H4Me) (21).

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Section: Discussionmentioning

confidence: 99%

Synthesis, Structure, and Reactivity of η²-N₂-Aryldiazoalkane Titanium Complexes: Cleavage of the N−N Bond

et al. 1998

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Azoalkan-Nitren-Spaltung auf einem Fe3-Cluster

Wucherer

Vahrenkamp

1987

Angew. Chem.

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Massenspektrometer erhitzt (Kontakt eines rnit NH4HC03 gefiillten Quarz-Tiegels mit dem Ionenblock; Vakuum-Generator ZAB-2F, l5O0C), oder es werden die beim Erhitzen von NH4HC03 in einem evakuierten Glaskolben auf ca. 120°C (Olbadtemperatur) gebildeten gasformigen Produkte iiber eine Strecke von > 30 cm in die Ionenquelle des Massenspektrometers geleitet. Man beobachtet nach ElektronenstoBionisation (Ionisierungsenergie 70eV, Emissionsstrom 50 PA) Signale bei m / z 17 (NG'), 18 (H20", N G ) , 44 (COT') und 62. Obwohl die Signalintensitaten stark schwanken und das Signal bei m/z 62 weniger als 1% der Intensitat des Signals bei m/z 44 hat, ist das Signal/ Rausch-Verhaltnis fur m/z 62 immer noch besser als 100: 1. Die exakte Massenbestimmung liefert fur m / z 62 einen Wert von 62.00002 Dalton, der nur rnit der Elementanusammensetzung CH203 (62.00039 Dalton) vertraglich ist; fur die nachstbeste Kombination, CH4N02, ist die berechnete Masse 62.02401 Dalton. Das Fehlen eines Signals bei m / z 79 wie auch das eines Ubergangssignals fur die Reaktion m/z 79m/z 62 + NH3

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Azoalkane‐Nitrene Cleavage on an Fe₃‐Cluster

Wucherer

Vahrenkamp

1987

Angew. Chem. Int. Ed. Engl.

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corresponding neutral molecule and not as fragment ions produced by loss of NH3 from ionized NH4HC03. As soon as the temperature used to evaporate the sample was lowered to ca. 100°C the m / z 62 ions disappeared and the intensity of the other signals also became much lower.Collision induced decomposition of the mass-selected m / z 62 ions (MS/MS experiments,['') yields the collisional activationig1 (CA) spectrum shown in Figure la. Both the pronounced loss of O H o by direct a-cleavage ( + m / z 45) and the elimination of neutral H 2 0 (+m/z 440e) and C 0 2 (+m/z 18°e) are compatible with our proposal that the m/z 62 ions are carbonic acid radical cations, 2 @ @ . m i zmlz -Fig. I. a) CA mass spectrum (collision gas: He) of mass-selected CH20'?@ions (m/z 62) generated by electron impact ionization of NH4HC03 followed by 70 eV ionization. b) NRMS spectrum of CH20Y" ions, using xenon for neutralization and oxygen for reionization.

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Spaltung der NN-bindung von diazirinen durch Ru3(CO)12

Cited by 21 publications

References 4 publications

Synthesis, Structure, and Reactivity of η²-N₂-Aryldiazoalkane Titanium Complexes: Cleavage of the N−N Bond

Synthesis, Structure, and Reactivity of η²-N₂-Aryldiazoalkane Titanium Complexes: Cleavage of the N−N Bond

Azoalkan-Nitren-Spaltung auf einem Fe3-Cluster

Azoalkane‐Nitrene Cleavage on an Fe₃‐Cluster

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Spaltung der NN-bindung von diazirinen durch Ru3(CO)12

Cited by 21 publications

References 4 publications

Synthesis, Structure, and Reactivity of η2-N2-Aryldiazoalkane Titanium Complexes: Cleavage of the N−N Bond

Synthesis, Structure, and Reactivity of η2-N2-Aryldiazoalkane Titanium Complexes: Cleavage of the N−N Bond

Azoalkan-Nitren-Spaltung auf einem Fe3-Cluster

Azoalkane‐Nitrene Cleavage on an Fe3‐Cluster

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Synthesis, Structure, and Reactivity of η²-N₂-Aryldiazoalkane Titanium Complexes: Cleavage of the N−N Bond

Synthesis, Structure, and Reactivity of η²-N₂-Aryldiazoalkane Titanium Complexes: Cleavage of the N−N Bond

Azoalkane‐Nitrene Cleavage on an Fe₃‐Cluster