Synthesis of an (.eta.3-allyl)(hydrido)iridium complex and its reactions with arenes and alkanes. Sequential intermolecular carbon-hydrogen oxidative addition and hydride-to-alkene migratory insertion reactions

Formation of Hydrido–η3‐Allyl Complexes of IrIII by Sequential Olefinic CH Bond Activation and CC Coupling of Alkenyl and Olefin Ligands

“…Crystal structure determinations of I*, 8a* and 8b*: A light yellow crystal of prismatic shape of complex I* was coated with epoxy resin and mounted in I I kappa diffractomeler equipped with ;in Enraf-Nonius FRSSXSH low-temperature device. The cell dimensions were refined by least-squares fitting the 0 valucs of the 25 reflections with a 20 range of [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] . The intensities were corrected for Lorentz and polarization effects.…”

Sequential Hydrocarbon C—H Bond Activations by 16-Electron Organometallic Complexes of Molybdenum and Tungsten

“…It is likely that the double C-H activation of cyclo hexane by A is in direct competition with trapping of A by PMe 3 as portrayed in Scheme 3. The competitive C-H activation by an unsaturated intermediate in the presence of a strong Lewis base is remarkable, yet it has been observed before (4,5) and is aided by low concentrations of the trapping agent relative to the cyclohexane solvent. In contrast to cyclohexane, methylcyclohexane under identical experimental conditions affords trace amounts of 2a-b and the exocyclic allyl hydride complex, Cp*W(NO)^3-C 7 Hu)(H), in two isomeric forms (7a-b) whose relative abundances are shown in Scheme 2.…”

“…Our contribution to this area of chemistry began with our recent discovery that Cp*M(NO)(hydrocarbyl) 2 complexes (Cp* = η 5 …”

“…For comparison, it may be noted that thermolyses of alkyl-allyl complexes of iridium at 120 °C are believed to form similar aliène complexes. However, these inter mediates have not been characterized or isolated, and they are only capable of effecting single C-H bond activations (5).…”

Utilisation of an η3-allyl hydride complex, formed by UV irradiation, as a controlled source of 16-electron (η5-C5Me5)Rh(CH2CHMe)

“…Bergman et al obtained a similar complex by reduction of (Z 5 -C 5 Me 5 )Ir(Z 3 -CH 2 CHCH 2 )Cl. 17 In view of the evidence that these experiments failed to facilitate the detection of the expected solvent complex, (Z 5 -C 5 Me 5 )Rh(CH 2 QCHMe)(Z 2 -toluene), a sample of 1 was photolysed with naphthalene at the slightly higher temperature of 233 K. Naphthalene was selected because aromatic resonance stabilisation energy effects work to stabilise the corresponding Z 2 -arene isomers as illustrated in studies of Cp*Rh(PMe 3 )(H) 2 . 18 Now, five new Cp* resonances are observed in the corresponding 1 H NMR spectrum.…”