spopsisPolyethylenimine (PEI) forms a copper chelate with a N/Cu ratio of about 5 and with extinction coefficients of about 175 at 63$0 A. and 4250 a t 2694 A. Solutions of PEI-copper chelate obey Lambert's and Beer's Iaws and show increased optical density in the presence of chloride ion. Above pH 4.25, hydrogen ion has little effect. A comparison with the copper chelate of polyvmylamine suggests that PEI has a highly, branched structure. Analysis of PEI via its copper chelate is described. 1993 1994 V r .

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The mass spectra of hexanal, heptanal and nonanal variously labeled with deuterium confirm γ‐hydrogen migration and β cleavage as the mechanism leading to [C2H4O]+˙ and [M  C2H4O]+˙, although the data on the latter are complicated by contributions from other, related paths. In addition, they show that three other major primary decomposition products, [M  C2H4]+˙, [M  H2O]+˙ and [C3H5O]+, all arise in large part by processes involving γ‐hydrogen migration to the oxygen atom. The ethylene lost to yield the first of these products consists of the α and β methylene groups. The loss of ethylene most likely occurs by way of a cyclobutanol intermediate, which, via alternative reaction paths, may well contribute to the yields of the other two products as well. These findings further extend the range of parallelism between photochemical and electron‐impact‐induced reactions.