Theoretical and Experimental Investigation of Oxenium Ions Arthur H. Winter, Department of Chemistry, Iowa State University, Ames, IA, 50011 Theoretical studies of Oxenium Ions. We have performed high-level multireference CASPT2/CASSCF computations on a variety of important oxenium ions, including the parent phenyloxenium ion as well as heteroaryl oxenium ions incorporating a ring nitrogen. Remarkably, we find that oxenium ions can adopt a variety of unusual low-energy electronic states including closed-shell and open-shell singlets and triplet states.
Experimental studies of oxenium ions. We have developed a novel photoprecursor to aryloxenium ions, protonated aryl hydroxylamines, which undergo heterolytic scission upon photolysis to yield aryloxenium ions, which can be studied by ultrafast laser flash photolyis experiments. 0.007
O
0.006
O
NH3+ hv
phenyloxenium ion
O
H2 O phenoxy radical
NH3+ OH OH
Absorbance(a.u.)
OH
10ps 15ps 20ps 30.4ps 50.4ps 100.4ps 494.4ps
O
0.005 0.004
O 0.003 0.002 0.001 400
500
Wavelength(nm)
600
