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 used to study the dissociation behavior of the gaseous Pt(CN)62− and Pt(CN)42− dianion complexes in order to probe the smallest stable dianion complex. Loss of neutral molecules from Pt(CN)62− occurs resulting in Pt(CN)52− and Pt(CN)42−, but no indication of the existence of Pt(CN)32− was found. This indicates that the lifetime of Pt(CN)32− is less than 4 μs (the flight time from the collision region to the detector). In contrast, all monoanion platinum–cyanide complexes were observed, i.e., Pt(CN)n− (n=1–6). The kinetic energy released in processes where monoanions are formed is much lower than the barrier height for the reverse reaction (>1.5 eV), which indicates that electron detachment is involved, e.g., Pt(CN)3− and CN− are not formed in the same dynamical process from Pt(CN)42−, or that the dynamics of the dissociation process is slow. For comparison, the Ru(bipy)32+*→[Ru(bipy)2−H]++bipyH+ reaction is associated with a kinetic-...