Probing the lowest coordination number of dianionic platinum-cyanide complexes in the gas phase: Dynamics of the charge dissociation process

Low-energy and high-energy collision induced dissociation techniques are us ed to study the dissociation behavior of the gaseous Pt(CN)(6)(2-) and Pt(C N)(4)(2-) dianion complexes in order to probe the smallest stable dianion c omplex. Loss of neutral molecules from Pt(CN)(6)(2-) occurs resulting in Pt (CN)(5)(2-) and Pt(CN)(4)(2-), but no indication of the existence of Pt(CN) (3)(2-) was found. This indicates that the lifetime of Pt(CN)(3)(2-) is les s than 4 mus (the flight time from the collision region to the detector). I n contrast, all monoanion platinum-cyanide complexes were observed, i.e., P t(CN)(n)(-) (n=1-6). The kinetic energy released in processes where monoani ons are formed is much lower than the barrier height for the reverse reacti on (>1.5 eV), which indicates that electron detachment is involved, e.g., P t(CN)(3)(-) and CN- are not formed in the same dynamical process from Pt(CN )(4)(2-), or that the dynamics of the dissociation process is slow. For com parison, the Ru(bipy)(3)(2+)*--> [Ru(bipy)(2)-H](+)+bipyH(+) reaction is as sociated with a kinetic-energy release of similar to0.3 eV (bipy=2,2(')-bip yridine). (C) 2000 American Institute of Physics. [S0021-9606(00)00240-3].