Gas-phase fragmentation of coordination compounds: Loss of CO2 from inorganic carbonato complexes to give metal oxide ions

Using electrospray ionization mass spectrometry, novel transition metal oxi de coordination complex ions are proposed as the products of the collision- induced dissociation (CID) of some carbonate complex ions through the loss of a mass equivalent to CO2. CID spectra of [(tpa)CoCO3](+) (tpa = tris(2-p yridylmethyl)methylamine), [(bispicMe(2)en)Fe(mu-O)(mu-CO3)Fe(bispicMe(2)en )](2+) (bispicMe(2)en = N ,N '-dimethyl-N ,N '-bis(2-pyridylmethy)ethane-1, 2-diamine) and [(bpbp)Cu2CO3](+) (bpbp(-) = bis[(bis-(2-pyridylmethyl)amino )methyl]-4-tertbutylphenolato(1-)), show peaks assigned to the mono- and di nuclear oxide cations, [(tpa)CoO](+), [(bispicMe(2)en)(2)Fe-2(O)(2)](2+) an d [(bpbp)Cu2O](+),as the dominant species. These results can be likened to the reverse of typical synthetic reactions in which metal hydroxide compoun ds react with CO2 to give metal carbonate compounds. Because of the lack of available protons in the gas phase, novel oxide species rather than the mo re common hydroxide ions are generated, These oxide ions are relevant to th e highly oxidizing species proposed in oxygenation reactions catalysed by m etal oxides and metalloenzymes. Copyright (C) 1999 John Wiley & Sons, Ltd.