INFRARED AND COLLISION-INDUCED FRAGMENTATION OF IRON ETHOXIDE CATIONS

The multi-photon infrared photo-dissociation (MPD) of iron ethoxide ca tions of the general form Fe+(EtOH)(m)(EtO)(n) has been studied in an ion trap using a line tuneable CO2 laser. The ions exhibit very charac teristic infrared absorption profiles which are shown to be quite diff erent from those recorded for Fe+(EtOH)(n) cluster ions. From a compar ison with solid state data, it is suggested that the mode responsible for absorption is a C-O stretch in the ethoxide group. To complement t he interpretation of the MPD data, the collision-induced dissociation (CID) of the same series of ions was promoted by the application of a tickle voltage to the end caps of the ion trap. Both MPD and CID gener ate the same fragment ions, but the relative intensities are different . A detailed study of Fe+(EtOH)(EtO) using isotopes reveals fragmentat ion pathways leading primarily to the loss of H-2, CH2O and CH3CHO, al l of which can be accounted for via a series of insertion and radical transfer steps. Central to many of the reactions is an initial inserti on step which results in the formation of HFe+(EtO)(2). (C) 1997 Elsev ier Science B.V.