Synthesis and characterization for five 7,16-Dibenzylated tetraaza[14]annulene nickel(II) complexes

Article abstract of DOI:10.1016/0277-5387(95)00312-3

The substitution reaction of tetraaza[14]annulene nickel(II) (1) with five various para-substituted benzyl bromides led to the corresponding 7,16-dibenzylated complexes in 43-60% yields. The mass spectra indicate the existence of molecular ion peaks due to the 7.16-dibenzylated products. The macrocyclic skeleton of the five complexes and their electronic spectra are hardly changed by the benzylation. The five nickel(II) complexes are in almost square-planar coordination, judging from the ligand-field transition bands. The olefinic proton signals at the 7-and 16-positions disappear on benzylation in the ¹H NMR spectra. The off-resonance decoupling peak at the 7-and 16-positions changes from a doublet to a singlet by the benzylation of 1 in ¹³C NMR spectra. The ¹³C NMR results are comparable with those of ¹H NMR.