Structure, bonding and reactions within protonated acetone-methanol cluster ions

We have studied the structure and reactivity of the acetone-methanol cluster series {(C3H6O)m(CH3OH)n}H+ as a function of cluster size. Conventional mass spectra are mainly dominated by the three series of protonated acetone-methanol cluster ions, (C3H6O)m = 1-3(CH3OH)nH+. In the CID spectra of the (C3H6O)1(CH3OH)nH+ series, we observed two different reaction channels: the loss of CH3OH and the loss of C3H6O. The former dominates regardless of the cluster size. For the (C3H6O)2(CH3OH)nH+ series, the CID result reveals a change in the preferred reaction pathway as a function of cluster size. For the (C3H6O)3(CH3OH)nH+ series, the loss of C3H6O dominates.

73Highlights► Structure and bonding change as a function of the number of acetones. ► Proton affinity is not a sufficient factor to determine the reactivity. ► Acetone molecules form a strong interaction with the proton bound methanol.