Supporting Information Synthesis and Characterization of Cationic Rhodium Peroxo Complexes Judy Cipot-Wechsler, a Danielle Covelli, b Jeremy M. Praetorius, a Nigel Hearns, a Olena V. Zenkina, Eric C. Keske, Ruiyao Wang, a Pierre Kennepohl*, b and Cathleen M. Crudden* a AUTHOR ADDRESS a Department of Chemistry, Queen’s University, Chernoff Hall, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6 and b Department of Chemistry, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1 cathleen.crudden@chem.queensu.ca; pierre.kennepohl@ubc.ca Figure S1. Crystallographically determined structures of [Rh(IPr)2(O2)(MeCN)2]BF4 (11BF4) (left) and of [Rh(SIMes)2(O2)(MeCN)2] CF3SO3 (12OTf) (right) displaying thermal ellipsoids drawn at the 50 % confidence level. Hydrogen atoms and counter-anion are omitted for clarity. Selected interatomic distances [Å] and angles [°] for 11BF4: Rh(1)–O(1), 1.974(2); Rh(1)–O(2), 1.980(3);