Electrospray and fast ion bombardment of mixed-valence polynuclear complexes based on MnII(bpy), (M= Ru, Os) and RuIII(NH3)5 units

A number of mixed-valence complexes containing Ru”‘(NH,),(X) (X=NI-&, py) units cyano bridged to -Ru”(bpy), or -Os”(bpy), moieties have been examined by positive electrospray (ES) and Cs’ fast ion bombardment (FAB) mass spectrometIy. Both sets of data yielded a substantial [M-PF,]+ signal and a number of charactkristic fragment ions involving the multiple loss of the PF,- anion. ES data provided clear information on multiply charged ions as well as a strong indication of Ru-NH, bond weakening when Ru”‘(NI-&), units are cyano bridged to OS”. The advantages of ES mass spectrometry for this class of compounds and the gas-phase redox chemistry of the investigated ions are discussed