Karsten Eller

Organometallic chemistry in the gas phase. A comparative fourier transform-ion cyclotron resonance/tandem mass spectrometry study

Abstract The study of selected examples of well-understood systems from the field of gas phase organometallic chemistry demonstrates that a comparison of ion/molecule reactions of “bare” transition metal ions with organic substrates in a Fourier transform-ion cyclotron resonance (FT-ICR) instrument with metastable ion dissociations of organometallic complexes occurring in field-free regions of a triple sector instrument is indeed meaningful. The major differences are due to multiple losses of ligands which are more pronounced in the FT-ICR experiments.

On the generation and identification of stable HCN/Cu(0) and HCN/Cu(0) complexes in the gas phase using neutralization/reionization mass spectrometry (NRMS)

Abstract Stable Cu(0) complexes of HCN and HNC have been generated and characterized by neutralization/reionization mass spectrometry (NRMS). Both complexes exhibit a minimum lifetime of 0.8 μs when generated from the corresponding HCN/Cu + and HNC/Cu + species in the gas phase. The collision-induced decomposition patterns of both the neutral and ionic complexes of HCN and HNC are in keeping with “end-on” structures.

Detection and characterization of competitive processes giving rise to isomeric products in the reactions of Fe+, Co+ and Ni+ with n-butyl cyanide

Abstract Two independent processes lead to loss of C 2 H 4 upon reaction of Co + with n -C 4 H 9 CN. A “marriage” of deuterium labelling with collision-induced dissociation (CID) spectrometry, viz. CID spectra taken from isotopomeric product ions generated from the same labelled precursor, helps to uncover mechanistic details of this particular system. While part of the C 2 H 4 is produced via “remote functionalization”, as is exclusively the case for Ni + , part is generated from internal positions in a manner analogous to the reaction of Fe + . The isomeric complexes Co(CH 3 CH 2 CN) + and CH 3 Co + CH 2 CN are formed, which can be distinguished and characterized by virtue of their CID spectra. Dehydrogenation proceeds for all three metal ions by remote functionalization, but this reaction is preceded by two different equilibria which give rise to different labelling distributions in the cases of Fe + and Ni + respectively.

Remote Functionalization of Carbon-Hydrogen and Carbon-Carbon Bonds by Bare Transition Metal Ions in the Gas Phase

The selective functionaIization of C-H bonds remains one of the major focuses of catalytic and organic chemistry. High selectivity is often achieved by the presence of activating groups which induce the reactivity of the neighbouring C-H bonds by, for example, polarizing the bond, thus making the hydrogen more acidic, or by generally weakening the C-H bond. The selective functionalization of hydrocarbon segments of a molecule remote from any functional group represents a great challenge. While such reactions are common to enzymes which coordinate a functional group and geometrically select a specific section of the molecule (see, for example, the enzymatic conversion of stearic to oleic acid. Scheme 1), only a few cases in solution chemistry are reported [1] where a similar principle seems to be operative.

Simple ligand exchange reaction or not, that is the question. But is it also metal ion dependent?

Abstract The late transition metal ions from Cr+ to Zn+ react with i-C3H7NCO (1) to form M(HNCO)+ and M(C3H6)+ complexes. Secondary reactions of both ions with 1 afford MC4H7NO+ ions. While for Cr+, Mn+, and Zn+ these products correspond to adduct complexes M(i-C3H7NCO)+, for Fe+-Cu+, at least partly, isomeric M(HNCO)(C3H6)+ complexes are formed.