Binding of molecular oxygen and alkenes to coordinatively unsaturated bipyridinium metal complexes in the gas phase

Bimolecular reactions of molecular dications: reactivity paradigms and bond-forming processes

“…Specifically, in the first step of the reaction of [Ru(bipy) 2 ] 2+ with 1-butene a mere association takes place, and only in a secondary reaction, bond activation occurs (reactions ( 13) and ( 14)). 106 Note that the formation of charge-separation products was not observed at all.…”

“…Hence, there needs to exist some cooperative interaction which renders the second addition more reactive than the first; Nielsen et al explained this remarkable effect by the steric demand of the bipy ligands. 106 The second aspect deserving attention is the fact that reaction (14) leads to the liberation of an open-shell species and yet electron transfer does not take place. Obviously, an extension of the set of substrates as well as dedicated labeling experiments would be very desirable.…”

Organic gas-phase ion chemistry

“…In a similar manner, Uggerud and coworkers measured the formation of M(bipy) 2 21 (M¼Cr, Ru or Os, bipy ¼ bipyridine) adducts with alkenes among other substrates. 148 Propene coordinates to Ru(bipy) 2 21 and the adduct undergoes further reaction resulting in alkene activation [eqns (41)-( 43)]. Similar results were obtained with 1-butene and, in conjunction with deuterium labeling experiments, led to the proposed mechanism shown in Scheme 4.…”

Mechanism for C–H bond activation in ethylene in the gas phase vs. in solution – vinylic or agostic? Revisiting the case of protonated Cp*Rh(C2H4)2

“…All these three processes are too slow to occur on a time scale comparable to the reactions under study. 64 The surprising combination of high reactivity of 3 with C 2 H 4 and C 2 D 4 and sluggishness in generation of stabilised 2 is in accord with this situation: the adduct resulting from the encounter between 3 and ethylene would possess excess energy compared with 2, and might easily back-dissociate to regenerate 3 and ethylene subsequent to any scrambling. In order to produce 2, a fraction of the ≥ 104 kJ mol -1 excess energy vs. 2 may be lost by either one of the mentioned cooling pathways, eventually blocking the back-dissociation pathway.…”