Electrospray mass spectrometry and molecular modeling study of formation and stability of silver complexes with...

The complex formation of the following diazaperylene ligands (L) 1,12-diazaperylene 1, 1,1'-bisisoquinoline 2, 2,11-disubstituted 1,12-diazaperylenes (alkyl = methyl, ethyl, isopropyl, 3, 5, 7), 3,3'-disubstituted 1,1'-bisisoquinoline (alkyl = methyl, ethyl, isopropyl, 4, 6, 8 and with R = phenyl, 11 and with pyridine 12), and the 5,8-dimethoxy-substituted diazaperylene 9, 6,6'-dimethoxy-substituted bisisoquinoline 10 with AgBF4 was investigated. Collision-induced dissociation measurements were used to evaluate the relative stabilities of the ligands themselves and for the [1:1]⁺ complexes as well as for the homoleptic and heteroleptic silver [1:2]⁺ complexes in the gas phase. This method is very useful in rapid screening of the stabilities of new complexes in the gas phase. The influence of the spatial arrangement of the ligands and the type of substituents employed for the complexation were examined. The effect of the preorganization of the diazaperylene on the threshold activation voltages and thus of the relative binding energies of the different complexes are discussed. Density functional theory calculations were used to calculate the optimized structures of the silver complexes and compared with the stabilities of the complexes in the gas phase for the first time.