ELECTROSPRAY AND FAST-ION BOMBARDMENT OF MIXED-VALENCE POLYNUCLEAR COMPLEXES BASED ON M(II)(BPY)(2) (M=RU, OS) AND RU-III(NH3)(5) UNITS

A number of mixed-valence complexes containing Ru-III(NH3)(4)(X) (X=NH 3, py) units cyano bridged to -Ru-II(bpy)(2) or -Os-II(bpy)(2) moietie s have been examined by positive electrospray (ES) and Cs+ fast ion bo mbardment (FAB) mass spectrometry. Both sets of data yielded a substan tial [M-PF6](+) signal and a number of characteristic fragment ions in volving the multiple loss of the PF6- anion. ES data provided clear in formation on multiply charged ions as well as a strong indication of R u-NH3 bond weakening when Ru-III(NH3)(5) units are cyano bridged to Os -II. The advantages of ES mass spectrometry for this class of compound s and the gas-phase redox chemistry of the investigated ions are discu ssed.