Gas-Phase Synthesis and Reactivity of Ligated Group 10 Ions in the Formal +1 Oxidation State

Electrospray ionization of the group 10 complexes [(phen)M(O 2 CCH 3 ) 2 ] (phen=1,10-phenanthroline, M = Ni, Pd, Pt) generates the cations [(phen)M(O 2 CCH 3 )] + , whose gas-phase chemistry was studied using multistage mass spectrometry experiments in an ion trap mass spectrometer with the combination of collision-induced dissociation (CID) and ion-molecule reactions (IMR). Decarboxylation of [(phen)M(O 2 CCH 3 )] + under CID conditions generates the organometallic cations [(phen)M(CH 3 )] + , which undergo bond homolysis upon a further stage of CID to generate the cations [(phen)M] +· in which the metal center is formally in the +1 oxidation state. In the case of [(phen)Pt(CH 3 )] + , the major product ion [(phen)H] + was formed via loss of the metal carbene Pt=CH 2 . DFT calculated energetics for the competition between bond homolysis and M=CH 2 loss are consistent with their experimentally observed branching ratios of 2% and 98% respectively. The IMR of [(phen)M] +· with O 2 , N 2 , H 2 O, acetone, and allyl iodide were examined. Adduct formation occurs for O 2 , N 2 , H 2 O, and acetone. Upon CID, all adducts fragment to regenerate [(phen)M] +· , except for [(phen)Pt(OC(CH 3 ) 2 )] +· , which loses a methyl radical to form [(phen)Pt(OCCH 3 )] + which upon a further stage of CID regenerates [(phen)Pt(CH 3 )] + via CO loss. This closes a formal catalytic cycle for the decomposition of acetone into CO and two methyl radicals with [(phen)Pt] +· as catalyst. In the IMR of [(phen)M] +· with allyl iodide, formation of [(phen)M(CH 2 CHCH 2 )] + was observed for all three metals, whereas for M = Pt also [(phen)Pt(I)] + and [(phen)Pt(I) 2 (CH 2 CHCH 2 )] + were observed. Finally, DFT calculated reaction energetics for all IMR reaction channels are consistent with the experimental observations.