NEGATIVE-ION FAST-ATOM-BOMBARDMENT MASS-SPECTROMETRY OF ANIONIC RUTHENIUM CARBONYL CLUSTER COMPLEXES

Bis(triphenylphosphine)iminium salts of a series of high-nuclear and anionic ruthenium carbonyl cluster complexes were characterized by use of the negative-ion fast atom bombardment mass spectrometry. With a m-nitrobenzyl alcohol matrix, all of the monoanionic cluster complexes gave relatively intense intact anion peaks [A](-) and all of the dianionic cluster complexes examined gave protonated monoanion peaks [HA](-), In some cases weak adduct ions were observed, which arose from the reaction of the cluster anions with the matrix during the bombardment process. The predominant fragmentation process of intact ions was found to be sequential loss of CO ligands and no loss of methyl, allyl or iodo ligand was observed However, dissociation of bromo ligand from [Ru6C(CO)(16)Br](-) and fragmentation of acetyl groups in [Ru5C(CO)(13)I-2(COMe)](-) and [Ru6C(CO)(16)(COMe)](-) were noted Degradation of cluster metal frameworks of [HRu10C(CO)(24)](-) and [Ru10C(CO)(24)](2-) into [HRu6C(CO)(16)](-) was observed These fragmentation and degradation patterns are comparable to their reactions in solution.