Physical Properties and Reactivities of Peroxomanganese(III) Complexes Timothy A. Jackson, Department of Chemistry, University of Kansas, Lawrence, KS 66045. Our goal is to contribute to an understanding of H2O2 activation by manganese centers by generating and characterizing catalytically-relevant intermediates, such as peroxomanganese(III) adducts. 1) Enhanced thermal stability of second generation MnIII intermediates and their activation by acid chlorides. Electronic Absorption
Electronic Absorption
MnIII(O2)( L7BQ)]+
5 eq. H2O2/ 1.5 eq Et3N
0.5 eq. CH3COCl MeCN/ -40 oC
MeCN/ -40 oC MnII(L7BQ)(NCMe)
2
???
]2+
[MnII(L7BQ)(OTf)2]
2) The reaction landscape of a MnII complex with superoxide and hydrogen peroxide, which features the conversion of a peroxomanganese(III) adduct to a bis(μ-oxo)dimanganese(III,IV) species was determined. EPR (20 K)
H2O2, Et3N MeCN [MnII(N4py)(OTf)]+ X-band EPR (5 K, parallel mode) [MnIII(O)2(N4py)]+
[MnIIIMnIV(µ-O)2(N4py)2]3+ Abs -40 oC
KO2 MeCN
+ [MnII(N4py)(OTf)]+
DFT Model [MnIII(O)2(N4py)]+
Leto, D. F., Day, V. W. and Jackson T. A. Manuscript in preparation.
