Reactions of the aryl complexes Rh(aryl){? 3 -P,O,P-[xant(P i Pr 2 ) ]} (1; = 3,5-Me C 6 H (a), 5 (b), 3,5-Cl (c), 3-FC 4 (d); xant(P 9,9-dimethyl-4,5-bis-(diisopropylphosphino)xanthene) with O , CO, and MeO CC?CCO Me have been performed. Under 1 atm pentane solutions afford dinuclear peroxide derivatives [Rh(aryl){? -P,P-xant(P }] (?-O (2a–2d) as yellow solids. In solution, these species are u...