Insertion of Strongly Electron Withdrawing Cyanoolefins into the C−H Bond in Pentamethylcyclopentadienyl−Rhodium(III) and −Iridium(III) Complexes Containing P−O or P−O−O‘ Coordinations

Complexes, Cp*MCl(MDMPP-P,O) (1a:  M = Rh, 1b:  M = Ir; Cp* = η5-C5Me5; MDMPP-P,O = PPh2(C6H3-2-O-6-MeO)) readily react with tcne or tcnq to form the 1:1 adducts [Cp*MCl(MDMPP-P,O)(ol)] (ol = tcne (c), tcnq (d)) (3ac:  M = Rh, ol = tcne; 3bc:  M = Ir, ol = tcne; 4ad:  M = Rh, ol = tcnq; 4bd:  M = Ir, ol = tcnq), derived from insertion of cyanoolefins into the C−H bond adjacent to the metal−O bond. Complex Cp*Ir(TDMPP-P,O,O‘) 2b (TDMPP-P,O,O‘ = P{C6H3-2,6-(MeO)2}(C6H3-2-O-6-MeO)2) bearing a (P,O,O‘) coordination was treated with 1 equiv of tcne, tcnq, or Me2-tcnq (e) to give the products in which one molecule of cyanoolefin was inserted, [Cp*Ir(TDMPP-P,O,O‘)(ol)] (5bc:  ol = tcne; 6bd:  ol = tcnq; 6be:  ol = Me2-tcnq). Reactions with 2 equiv of cyanoolefin gave the products [Cp*Ir(TDMPP-P,O,O‘)(ol)2] (7bc:  ol = tcne; 8bd:  ol = tcnq), in which insertion occurred at two C−H positions adjacent to the Ir−O bonds. Structural data for 3ac, 3bc, 4ad, 5bc, and 7bc are described.