Cyclic ion mobility of doped [MAu 24 L 18 ] 2- superatoms and their fragments (M = Ni, Pd and Pt; L = alkynyl).

Collision-induced dissociation and high-resolution cyclic ion mobility mass spectrometry, along with quantum chemical calculations and trajectory simulations, were used to compare the structures of isolated [MAu 24 (CCR) 18 ] 2- , M = Ni, Pd, or Pt, and their associated fragment ions. The three different alkynyl ligand-stabilized (CCR, R = 3,5-(CF 3 ) 2 C 6 H 3 ), transition metal-doped, gold cluster dianions showed mutually resolvable collision cross sections (CCS), which were ordered consistently with their molecular structures from X-ray crystallography. All three [MAu 24 (CCR) 18 ] 2- species fragment by sequential diyne loss to form [MAu 24 (CCR) 18- n ] 2- , with n up to 12. The resultant fragment isomer distributions are significantly n - and M-dependent, and hint at a process involving concerted elimination of adjacent ligands. In particular [NiAu 24 (CCR) 18 ] 2- also fragments to generate alkyne-oligomers, an inference supported by the parallel observation of precursor dianion isomerization as collision energy is increased.