Use of barbituric acid as a "padlock" to generate azamacrocyclic complexesof Ni(II) containing fused aromatic rings

1,5-Di(4,5-disubstituted-2-aminophenyl) penta-1,5-diaza-1,3-dienatonickel(I I) chlorides are reacted with formaldehyde and barbituric acid in the prese nce of catalytic amount of perchloric acid to synthesize two members of a n ew type of aza macrocyclic complex of Ni(II). The macrocyclic complexes, wh ich are diamagnetic, have been characterised by conductivity, electronic sp ectra, thermal analysis and NMR (H-1 and C-13) spectroscopy. The structure of the cation in one of the macrocyclic complexes has been examined by usin g molecular mechanics.