Identification of the short-lived Au(N3)42− dianion from its Coulomb explosion products

Abstract In high-energy collisions between Au(N 3 ) 4 − anions and sodium vapor, electron transfer occurred to produce Au(N 3 ) 4 2− dianions. These were short-lived (sub microsecond) and Coulomb exploded into Au(N 3 ) 3 − and N 3 − with a kinetic energy release of 2.6 ± 0.5 eV. In the product ion spectra, peaks correspond to fragment ions formed from collisionally activated Au(N 3 ) 4 − parent anions. Loss of one or more N 3 or N 2 produced AuN n − complexes ( n  = 1–4, 6, 9–10) whereas complexes with n  = 5, 7, and 8 were not detected. These ions can be assigned to gold–nitride–azide complexes Au(N) x (N 3 ) y − ( x  = 0–2 and y  = 0–4). Cationic complexes were measured for n  = 1–4 and 6. Sodium vapor collision experiments were also performed for Au(N 3 ) 2 − , which is generated in situ by the spontaneous reduction of Au(N 3 ) 4 2− and concurrent azide dissociation. In this case there was no clear signature indicative of the formation of a dianion. The formation of dianions cannot be excluded, however, since such ions may decay by electron emission instead of dissociation into two singly charged fragment ions.