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.