Treatment of cerous Cp R 3 Ce(thf) (Cp R = C 5 H 4 R; R = H, Me) with the halogenating reagents C 2 Cl 6 , TeBr 4 , and I 2 afforded the ceric halides Cp R 3 CeX (X = Cl, Br, I) in high yield. Subsequent salt metathesis with sodium alkoxides and siloxides led to a series of alkoxy and siloxy derivatives. Compounds Cp R 3 CeOR′ with R′ = Me, Et, CH 2 tBu, iPr, tBu, SiMe 3 , SiEt 3 , Si(iPr) 3 SiPh 3 (and Si(OtBu) 3 ) have been isolated and characterized by 1 H, 13 C, and 29 Si NMR and DRIFT spectroscopy, magnetic measurements, X-ray structure analyses, cyclic voltammetry, and elemental analyses. The ceric complexes Cp R 3 CeX and Cp R 3 CeOR′ are isostructural, featuring terminal ligands X and OR′. The magnetic measurements revealed temperature-independent paramagnetism (TIP), with positive magnetic susceptibilities in the range χ 0 (1.53−3.9) × 10 −4 emu/mol. Cyclic voltammetry indicated two types of redox processes: (a) chemical and electrochemical reversibility for halide and siloxide complexes and (b) EC-or ECE-type mechanisms for the alkoxides (chemical reversibility at high scan rates). In all cases formal potentials could be determined ranging from −0.583 V vs Fc/Fc + for Cp 3 CeI to −1.259 V vs Fc/Fc + for Cp Me 3 Ce(OEt). The electrochemical data revealed an increase in stabilization with respect to reduction of the cerium(IV) center in the series I < Br < Cl < siloxy < alkoxy ligand and a better stabilization with Cp Me in comparison to Cp ligands by approximately 0.05−0.1 V. As a result, an improved stabilization of Ce(IV) was observed for more strongly electron donating ligands.

Capillary electrophoresis‐mass spectrometry often lacks sufficient limits of detection for trace substances in the environment due to its low loadability. To overcome this problem, we conducted a feasibility study for column‐coupling isotachophoresis to capillary electrophoresis‐mass spectrometry. The first dimension isotachophoresis preconcentrated the analytes. The column‐coupling of both dimensions was achieved by a hybrid capillary microfluidic chip setup. Reliable analyte transfer by voltage switching was enabled by an in‐chip capacitively coupled contactless conductivity detector placed around the channel of the common section between two T‐shaped crossings in the chip connecting both dimensions. This eliminated the need to calculate the moment of analyte transfer. A commercial capillary electrophoresis‐mass spectrometry instrument with easily installable adaptations operated the setup. Prior to coupling isotachophoresis with capillary zone electrophoresis‐mass spectrometry, both dimensions were optimized individually by simulations and verified experimentally. Both dimensions were able to stack/separate all degradation products of glyphosate, the most important herbicide applied worldwide. The first dimension isotachophoresis also removed phosphate, which is a critical matrix component in many environmental samples. Enrichment and separation of glyphosate and its main degradation product aminomethylphosphonic acid by the two‐dimensional setup provided an excellent limit of detection of 150 pM (25 ng/L) for glyphosate.