Detlev Sülzle

Generation and characterization of neutral and cationic 3-sila-cyclopropenylidene in the gas phase: Description of a new BEBE tandem mass spectrometer

Abstract Collision-induced dissociation of mass-selected SiC 2 X + 2 species (X = H, D), generated by electron impact ionization of ClSi(CX 3 ) 3 (X = H, D), gives rise to spectra which are consistent with the structure of the theoretically predicted cation radical of 3-silacyclopropenylidene ( 1 + ). This species can be successfully neutralized and reionized under the conditions of neutralization-reionization mass spectrometric experiments, thus supporting previous theoretical predictions that 3-silacyclopropenylidene ( 1 ) is a stable molecule in the gas phase. A description of the BEBE tandem mass spectrometer is given.

Neutralization-reionization mass spectrometry as a novel probe to structurally characterize organic ligands generated in the Fe(I)-mediated oligomerization of acetylene in the gas phase

Abstract Relatively detailed information on the structures of the ligands “C2xH2x” formed in the Fe+ -mediated oligomerization of acetylene (xC2H2 → C2xH2x ; x = 2–4) in the gas phase is provided by subjecting the resulting Fe(C2xH2x)+ systems to a neutralization—reionization mass spectrometry (NRMS) experiment. It is shown that for x = 2 the preferred structure corresponds to the Fe(C2H2)+2 complex 3+. Isomerization to Fe(cyclobutadiene)+ 4+ or the formation of a ferracyclopentadiene ion 5+ are both negligible. The addition of a further C2H2 ligand to 3+ gives rise to a NR mass spectrum which clearly indicates that cyclotrimerization to a benzene ligand has occurred (1+ → 2+) to some extent. Addition of a further C2H2 molecule to the Fe(C6H6)+ complex 2+, however, does not result in the formation of a Fe(cyclooctatetraene)+ complex 8+. Obviously, the barrier for the isomerization Fe(C2H2)(C6H6)+ (6+) → Fe(C8H8)+ (8+) is too high. It is suggested that NRMS may be superior to other mass spectrometric techniques to probe the structural features of the organic ligands attached to transition metal ions.

Experiments aimed at generating the long-sought-after ethylenedione (OCCO) by neutralizationreionization mass spectrometry

While Oue5f8Cue5f8Cue5f8O·+ is easily accessible from different sources and can be structurally characterized by means of collisional activation, all attempts failed to successfully neutralize C2O·+2 to the long-sought-after ethylenedione Oue5f8Cue5f8O. A comparison with previously published theoretical studies of the geometries of C2O·+2, C2O·-2 and C2O2 clearly indicates that vertical electron transfer is not likely to result in the formation of an observable C2O2 neutral, in keeping with our neutralization-reionization results.

The generation and identification of triplet vinylidene, [H2CC]:, by neutralization-reionization mass spectrometry

Neutralization of a beam of vinylidene anions, [CH2ue5fbC]−•, by xenon gives rise to a stable C2H2 species, having a lifetime ⩾ 0.4 μs. Re-ionization with oxygen generates a species which is identified by its collisional activation mass spectrum as the vinylidene radical cation, [CH2ue5fbC]+•.

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.

On the existence of novel nitrides and oxides of copper; CuN, CuO2 and CuNO

Abstract Electron impact ionization of anhydrous copper(II) nitrate yields the copper-containing cations CuN + , CuO + , CuNO + 2 . Collisional activation is used to structurally characterize the ions which can also be transformed to their corresponding neutral analogues by using neutralization-reionization mass spectrometry.

Gas-phase generation and structural characterization of SiC2H and SiC2H+ by neutralization—reionization mass spectrometry: evidence for the existence of silicon acetylide (HCCSi) and its cation HCCSi+

Abstract Silicon acetylide (HCue5fcCSi ) and its cation HCue5fcCSi+ are generated and characterized in the gas phase by mass-spectrometric methods (neutralization—reionization mass spectrometry). The various collision spectra rule out a connectivity Cue5fcCSiH; rather,they are in keeping with the assignment of HCue5fcCSi for both the radical and the cation, thus confirming previous ab initio MO calculations.

Cationic and neutral nitrosamide: viable molecules in the dilute gas phase

Abstract Nitrosamide, NH 2 NO, has been generated and characterized in the dilute gas phase by means of neutralization reionization mass spectrometry in combination with extensive isotopic labelling. The molecule was found to be stable under these conditions having a minimal lifetime in the microsecond time frame. No evidence for isomerizations either of the cationic or the neutral nitrosamide was obtained.

Computational evidence for stable inorganic fullerene-like structures of ceramic and semiconductor materials

Theoretical electronic structure techniques have become an indispensible and powerful means for predicting molecular properties and designing new materials. Based on a density functional approach and guided by geometric considerations we provide evidence for some specific inorganic fullerene-like cage molecules of ceramic and semiconductor materials which exhibit high energetic stability and point group symmetry as well as nearly perfect spherical shape.

The gas-phase generation and characterization of butatrienylidene H2CCCC : by neutralization-reionization mass spectrometry

Abstract Experiments are reported on the successful gas-phase generation of butatrienylidene H 2 Cue5fbCue5fbCue5fbC: using the technique of neutralization—reionization mass spectrometry.