Ligand and Metal Effects in the Gas‐Phase Fragmentation of Thiomethoxymethyl Complexes

Abstract While the collision‐induced dissociation (CID) of the mass‐selected cation [(Ph 3 P) 2 Pt(CH 2 SCH 3 )] + causes the selective liberation of PPh 3 , the diphosphine complex [(dppe)Pt(CH 2 SCH 3 )] + (dppe=1,2‐ bis (diphenylphosphino)ethane) ejects C 2 H 4 , CH 2 S, and (CH 3 ) 2 S upon CID. The analogous palladium complexes [(Ph 3 P) 2 Pd(CH 2 SCH 3 )] + and [(dppe)Pd(CH 2 SCH 3 )] + show similar reactivity, except that C−H‐bond activation is completely lacking. For other bidentate diphosphine ligands such as dppm, dppv, dppp, dppb, dppbz, dppf, and xantphos, a correlation of the dominant reaction channels with the bite angle is observed. For bite angles > 90°, hydrogen‐atom transfer is favored, as evidenced by an increase in dimethyl‐sulfide loss. For smaller bite angles (< 90°), intra molecular activation of the thiomethoxymethyl ligand predominates, thus resulting in increased losses of thioformaldehyde and ethene. The results of the CID experiments are compared with those for [(bipy)Pt(CH 2 SCH 3 )] + , for which the loss of C 2 H 4 is observed as the main process. DFT calculations for the complexes [(dppe)Pt(CH 2 SCH 3 )] + and [(bipy)Pt(CH 2 SCH 3 )] + together with the experimental findings uncover subtle differences in the underlying reaction mechanisms.