Carbon-13 NMR and EHMO studies on Seyferth's [Co3(CO)9CCO]+ cluster: to bend or not to bend

Photochemistry of aryl azides: detection and characterization of a dehydroazepine by time-resolved infrared spectroscopy and flash photolysis at room temperature

“…There is no evidence for the existence or participation of azirine 4 in these reactions. 19 Comparison of these results with product, kinetic, and spectral data for phenyl azide itself shows excellent correspondence. 5 On this basis we conclude that ring expansion to the dehydroazepine is also the dominant pathway in the irradiation of phenyl azide.…”

“…1974, 96, 7491. (19) We cannot exclude with certainty the possible formation of 4 and its subsequent isomerization to 3 in less than 20 ns.…”

[Co2(CO)6(Alkynyl)] Complexes of Dibenzosuberyl and Dibenzosuberenyl Carbocations: Dibenzotropylium or Dibenzoheptafulvene?

“…It has been unequivocally demonstrated by a combination of NMR spectroscopic and X‐ray crystallographic data, together with extended Hückel molecular orbital calculations, that protonation of an [Co 2 (CO) 6 (alkynol)] cluster yields a markedly stabilised carbocation (Scheme ). This may be envisaged as occurring either (a) through π donation of the new C=C bond formed at the expense of a single Co−C linkage, or (b) through σ back‐donation from a d‐orbital lone pair.…”

A Trigold(I) Ketenylidene Cation

“…Transition-metal ketenides and ketenylidenes have been studied as models for plausible intermediates in carbon monoxide chemistry . The first well-defined transition-metal ketenylidene complex was the highly electrophilic [Co 3 (CO) 9 (CCO)] + , described by Seyferth et al − Shriver and co-workers studied a series of generally nucleophilic, anionic ketenylidenes, − including one featuring a mixed-metal [Fe 3 Cu] core . Several of these complexes display remarkable C–C coupling and cleavage reactions .…”