The conformation of 4-phenylcyclohexanone in solution by 1H- and 13C-Lanthanide induced shift (L.I.S.) analysis : Evidence in favour of phenyl over t-butyl as a conformational lock

The degree of pucker of the cyclohexanone ring in 4-phenylcyclohexanone has been refined by L.I.S. analysis. The results indicate puckering intermediate between that in cyclohexanone and 4-t-butylcyclohexanone, suggesting that phenyl may be preferable to t-butyl as a locking group in conformational analysis. The Yb (fod)3 shift reagent, although binding primarily at the carbonyl oxygen atom, also complexes weakly with the phenyl group.     

On the importance of a correct choice of model for lanthanide ion binding in the interpretation of lanthanide-induced N.M.R. shifts: the adamantanone problem

Interpretation of ¹H and ¹³C lanthanide-induced N.M.R. shifts on adamantanone depends critically on the model chosen for lanthanide ion binding.     

Photoelectron spectra of acetaldehyde and acetyl halides

The He I photoelectron spectra of acetaldehyde and acetyl fluoride, chloride and bromide have been obtained. The spectra are interpreted in terms of molecular orbital structures, by comparison with results for related molecules and by a consideration of the inductive and resonance effects. The results of CNDO/2 and INDO semi-empirical calculations are also reported. It is found that the oxygen “lone pair” is progressively stabilized as the electronegativity of the halogen increases. The vibrational structure of the first photoelectron band of acetaldehyde is compared with the observed structure of Rydberg transitions in the optical spectrum.     

The tricyanomercurate(II) ion

The tricyanomercurate(II) ion, [Hg(CN)₃]^?, is isolated in the form of its solid caesium salt from a 1:1:1 ethanolic solution of CsF, KCN and Hg(CN)₂, and characterised by IR and Raman vibrational spectroscopy. Assignments are made for the CN and HgC stretching vibrations and the HgCN bending vibrations. The spectra are consistent with the [Hg(CN)₃]^? ion occupying a site of C₁ symmetry.