Gas Phase Chemistry of Bis(pentamethylcyclopentadienyl)samarium

The gas phase chemistry of bis(pentamethylcyclopentadienyl)samarium, (C 5 Me 5 ) 2 Sm, was studied by Fourier transform ion cyclotron resonance mass spectrometry (FTICR/MS). Positive electron impact (EI) spectra showed the formation of (C 5 Me 5 ) 2 Sm +, (C 5 Me 5 )Sm +, and Sm + . All three ions reacted with (C 5 Me 5 ) 2 Sm by charge transfer, as verified by double-resonance techniques, and (C 5 Me 5 )Sm + also formed the (C 5 Me 5 ) 3 Sm 2 + ion in a condensation reaction with neutral (C 5 Me 5 ) 2 Sm. The laser desorption/ionization (LDI) spectra showed, in addition to (C 5 Me 5 ) 2 Sm +, (C 5 Me 5 )Sm +, and Sm +, the formation of (C 5 Me 4 H)Sm + and (C 5 Me 4 CH 2 )Sm + . The latter species most probably involves a tetramethylfulvenide ligand. Access to all of the ionic species cited here could also be obtained by reacting laser-desorbed Sm + ions with pentamethylcyclopentadiene, C 5 Me 5 H. (C 5 Me 4 CH 2 )Sm +, (C 5 Me 4 H)Sm +, and (C 5 Me 5 )Sm + were formed as primary products, and the metallocene ion (C 5 Me 5 ) 2 Sm + resulted from the rapid addition of C 5 Me 5 H to (C 5 Me 4 CH 2 )Sm + .