Trimethylsilyl Perrhenate—A Nonionic Reagent Soluble in Organic Solvents for the Preparation of Perrhenates

Unexpected peaks in electron ionisation mass spectra of trimethylsilyl derivatives resulting from the presence of trace amounts of water and oxygen in gas chromatography/quadrupole time‐of‐flight systems

“…The presence of traces of oxygen in the carrier and collision gas or a leak at the junction of the capillary column and the mass spectrometer may induce attack on the filaments and result in the formation of the well‐known rhenium oxide Re 2 O 7 . This oxide is converted into TMS perrhenate (ReO 4 Si(CH 3 ) 3 ) (M = 323.9823 and 321.9794 for 187 Re and 185 Re, respectively) by reaction with silylating reagents . Its fragmentation affords fragment ions at m/z 308.9584 and 306.9551 [M – CH 3 ] + , 293.9343 and 291.9321 [M – 2CH 3 ] + and 278.9111 and 276.9088 [M – 3CH 3 ] + .…”