Investigation of metal-ion complexes of triazino crown ethers with podand arms by electrospray ionization

Double-armed triazino diaza crown ethers form stable complexes with alkali cations, In electrospray ionization [C2M](+) ions from 2 : 1 complexes appe ar additionally to the [CM](+) ions (C = crown ether ligand, M = metal). Th e portion of 2 : 1 complexes depends on the podand type. On collision-induc ed dissociation the [(CCM)-C-1-M-2](+) ions of asymmetrical 2 : 1 complexes form [CM](+) fragments with different intensities in correspondence to the complex stability. Triazino crown ethers with donor-active hydroxyalkyl po dands give more stable 1 : 1 complexes with K+, However, this was only foun d in the larger of the 1:we ring sizes compared. The electrospray ionizatio n of solutions composed of Mg-(II), Mn-(II), Ni-(II), Cu-(II), Zn-(II) or M g-(II) nitrates and triazino crown ethers generates four different types of metal complexes. However, the sum of all complex ions is only small compar ed to the total ion sum. Crown ethers without acidic hydrogen form [(CMNO3) -N-(II)](+) ions. Hydroxyalkyl substituted triazino crown ethers produce [( C - H)M-(II)](+) ions. With copper containing solutions of some crown ether types additionally [CCu(I)](+) are obtained at higher cone voltages. Only with Cd2+ doubly-charged complex ions like [CM(II)](2+) are found with sign ificant intensities. In all cases the conventionally protonated molecule ap pears as the base peak in the ESI spectra.