ion. In this procedure only one of the three-amine groups of diethylenetriamine
is involved in the in situ condensation reaction and
other amine groups are intact. The copper(II) complex is neutral
due to deprotonation of the N–H of the pyrrole and the amide moieties.
The primary amine group of the ligand is engaged in coordination
to the copper(II) ion and can be subsequently condensed
with various carbonyl compounds to study the variation and fine
tuning of stability, reactivity and electronic properties of such
complexes as were reported before [20–26].
The infrared spectrum of the complex shows the characteristic
bands of the respective ligand moieties. The C–N band of the
amide group appeared in 1513 cm1 shifted to higher energy in
comparison with similar amide groups, indicating coordination
to the copper ion. The bands assigned as C@O and C@C vibrations
of the amide and pyrrole groups are present at 1558 cm1 and
1404 cm1, respectively [27]. The former band shifted to the lower
frequency as compared to the typical free amide. The complex
presents the band assigned to the NH2 anti-symmetric stretching
vibrations modes at 3230 cm1 and 3207 cm1, while in the free
amine these bands appear at lower frequencies. The NH stretching
vibration mode also showed at 3132 cm1 [27]. A medium band
at 468 cm1 is characteristic of Cu–N vibration [28]. The wide
broad band about 3364 cm1 confirms well the presence of lattice
H2O.