Generation of supraclusters and nanoclusters using laser desorption/ionisation mass spectrometry

Laser desorption/ionisation of discrete molecular clusters combined with ti me-of-flight (TOF) or Fourier-transform ion cyclotron resonance (FTICR) mas s spectrometry affords spectra in which extensive higher mass clusters are observed. The size of the largest cluster aggregates (or supraclusters) is of the same order of magnitude as nanoclusters. The spectra obtained using TOF mass spectrometry sometimes exhibit post-source decay fragmentation, de pending upon the operational conditions employed during data acquisition, w hich, although providing useful data on the ligand dissociation dynamics, c omplicate spectral interpretation. Complementary FTICR mass spectra are fre e of such features. The identities of the supra/nanoclusters generated from the molecular cluster precursors have not been conclusively established bu t are mostly coordinatively unsaturated. Density functional molecular orbit al calculations have identified the possible structures of the comparativel y simple electronically unsaturated system, [Ru-3(CO)(6)](-), that provides a clue to the aggregation mechanism.