Ring destruction and carbide formation in niobium-PAH complexes

Gas phase complexes between niobium atoms and the polycyclic aromatic hydro carbons (PAHs) pyrene (C16H10) and coronene (C24H12) are produced in a mole cular beam using laser vaporization in a pulsed nozzle cluster source. Cati on complexes are studied with time-of-flight mass spectrometry and mass-sel ected photodissociation. Mass distributions and fragmentation patterns for Nb-x-(PAH)(y). complexes are significantly different from those found previ ously for other M-x-(PAH)(y) complexes. Masses indicating the formation of metal-hydrocarbons and metal-carbides are prominent. Larger complexes add i ntact PAH moieties to the strongly bound mono-metal adducts. Niobium is sig nificantly more reactive with PAH species than other transition metals stud ied to date. (C) 2001 Elsevier Science B.V. All rights reserved.