Inovganic Chemistry Laboratories, Irn9eria2 College, London SW7 2AY) Summury Equimolar mixtures of Ln(fod), (fod = C,F,COCHCOCMe,) and C,F,CO,Ag act as shift reagents for alkenes in CCI, or CDC1, solution.

The ('A& and 'Ag states of oxygen have been produced by direct laser (He-Ne and Nd-YAG) excitation of oxygen at high pressure dissolved in a suitable solvent, and their reactivities with various substrates investigated. For 9,lO-dimethylanthracene and 1,3-diphenylisobenzofuran, the quantum yields for ('A& excitation are, within experimental error, twice those for 'Ag excitation. In the reactions of 'Ag oxygen with 9,lO-dimethylanthracene and tetraphenylcyclopentadienone, both chemical reaction (rate kr) and physical quenching (rate kq) are observed. For 9,lO-dimethylanthracene, kq/kr -0.6, and for tetraphenylcyclopentadienone kq/kr -1.7. With 1,3-diphenylisobenzofuran, k,/kr is in the range 0-1. It is shown unambiguously that 'Ag oxygen reacts with two tertiary amines, triethylamine and tropinone, in addition to being quenched. For triethylamine, kqlkr -11.* The other low lying singlet state of oxygen, 'Xi, which is frequently also formed, is apparently very readily quenched to the 'Ag level.' 1661

Simultaneous electronic transitions have been observed for solutions of 1-chloroanthracene and other aromatic hydrocarbons in the presence of oxygen under pressure. In these, the organic molecule is excited to its lowest triplet state, and the oxygen undergoes a 1Ag-3Ci transition. The simultaneous transitions are much more intense than the perturbed singlet-triplet transitions.

K epz t ) Summary Irradiation of 2-nitrocycloheptanone in ethanol or acetonitrile leads to the formation of N-hydroxy-2,sdioxoazacyclo-octane ; analogous reactions are reported for 2-nitrocyclohexanone and a-nitrocamphor.

67 SummaryThe rates of nitration in sulphuric acid of 1,10-phenanthroline coordinated to rhodium(Ill) and cobalt(Ill) in a number of complexes have been measured and found to be much greater in these complexes than in free phenanthroline under the same conditions. Relative rates are generally higher in those complexes which bear the smaller overall positive charges, but these charges may be modified by protonation of the other ligands in the complexes.Contrary to earlier reports, some other electrophilic substitutions do not occur in a variety of phenanthroline complexes.