Intraionic, interligand proton transfer in collision-activated macrocyclic complex ions of nickel and copper

Intraionic, interligand proton transfer in collision-activated macrocyclic complex ions of nickel and copper has been observed. The macrocyclic ligand 1,4,8,11-tetraazacyclotetradecane (cyclam) or tris(2-aminoethyl)amine (tren) can transfer, after collision activation, one of its amino protons to an anion, but not to a solvent molecule, adducted to the complex; the neutral, protonated anion then leaves the complex. Proton transfer from the macrocycle to an adducted neutral, aromatic nitrogen base is also possible provided that the proton affinity of the base is sufficiently high.