Abstract
Three novel diazacrown ether ligands, namely 17-, 18-, and 20-membered O2N2-donor macrocycles derived from 3,3'-[butane-1,4-diylbis(oxy)]bis(2-naphthalenecarbaldehyde), were prepared and characterized by H-1 and C-13 NMR spectroscopy and mass spectra. Their host-guest interaction with Ni(II) was studied in DMSO-d (6) using H-1 NMR spectroscopy. The stoichiometry of the complex in each case in the concentration range examined was determined to be 1:1 using the continuous variation method (Job's plot). The 17-membered O2N2-donor macrocycle in which the two nitrogen atoms are tethered by three methylene units binds Ni(II) more strongly than the other two macrocycles do.