Infrared spectroscopic study of the protonated ligand salts of a 15-membered dioxa-diaza macrocycle

The 15-membered mixed dioxa-diaza macrocycle 5,6,14,15-dibenzo-1,4-dioxa-8,12-diazacyclopentadeca-5,14-diene (L) by reactions with a series of sodium salts NaX (X = picrate, ClO₄, BF₄, PF₆ and BPh₄) in acetonitrile and methanol solution yielded the protonated macrocyclic salts with different proton-to-ligand ratio as well as different modes of inside and outside macrocycle protonation and hydrogen bonding systems. Infrared spectra of the ion-pair compounds H(L)]X with intraligand protonation as well as H(L)₂]X and H₂(L)₃](X)₂ with interligand protonation, have been studied. The results obtained are discussed with respect to reported X-ray structure data of these compounds.