610
A.A. Khandar, K. Nejati / Polyhedron 19 (2000) 607–613
bis(5-phenylazo
salicylaldehyde)diethylene
triimine
to the IR spectra of the ligand. Therefore complex IV is also
(5PHAZOSALTEDA) were obtained as red microcrystals;
the microcrystals were filtered off, washed with 10 ml of
absolute ethanol and then recrystallized from ethanol–
chloroform (1:3, v/v).
four-coordinate via ONNO of the ligand atoms.
3.2. Crystal structure of [bis(5-phenylazo salicylaldehyde)-
trimethylen diiminato]copper(II) (Cu5PHAZOSALTN) (III)
2.3.3. Complexes
The crystal structure and unit cell diagram of complex III
are illustrated in Figs. 1 and 2, respectively. The selected
bond distances and angles are given in Table 4.
All complexes were prepared in a similar manner. A solu-
tion of 0.004 mole of Cu(CH3COO)2P4H2O in 10 ml of
ethanol was added to an ethanol–chloroform (1:1, v/v) solu-
tion containing 0.004 mole of ligand and refluxed for 1 h.
The obtained brown solution was left at room temperature
and brown microcrystals were collected by filtration, washed
with 15 ml of ethanol and then recrystallized from ethanol–
chloroform (2:1, v/v).
The coordination geometry around copper can be
described as a near square-planar. The Cu–O(1) and Cu–
˚
O(19) distances of 1.903(5) and 1.931(6) A are similar
˚
to the corresponding value [Cu–O(2), 1.915(7) A] in
N,N9-trimethylene bis(salicylaldehyde imine)copper(II),
Cu(sal2tn), as reported by Xiong et al. [12], and the differ-
ences are not significant, but the differences between Cu–
˚
O(1) and Cu–O(19) with Cu–O(1) [1.840(9)A] in
3. Results and discussion
Cu(sal2tn) are probably just significant.
The Cu–N(1) and Cu–N(19) distances are 1.949(7) and
˚
3.1. Syntheses
1.962(7) A. The corresponding values of complex
˚
Cu(sal2tn) are 1.954(7) and 1.995(8) A.
The 5-phenylazo salicylaldehyde(pre-ligand),Schiffbase
ligands and related copper complexes were obtained in good
yield and purity. The pre-ligand and Schiff base ligands were
characterized by 1H NMR and IR and mass spectroscopy.
Copper complexes were characterized by elemental anal-
ysis and IR spectroscopy. All physical and characterization
data for the ligands and complexes are given in Tables 2 and
3, respectively. In the mass spectra of 5-phenylazo salicyl-
aldehyde and the related Schiff base (5PHAZOSALO-
PHEN), [Mq1], M and [MyC6H5N2] for aldehyde and
[My2*C6H5N2] for Schiff base were observed. For the IR
spectra of the four title complexes, n(C_N)shiftedtoalower
wavenumber by 10–30 cmy1 upon coordination. On theother
hand, the disappearance of the OH band of free ligands in
copper(II) complexes indicates that the OH group has been
deprotonated and bonded to the metal ions as –Oy.
The bond angles O(19)–Cu–O(1), N(19)–Cu–N(1),
N(1)–Cu–O(19) and N(19)–Cu–O(1) are 79.8(2),
95.7(3), 171.9(3) and 171.8(3)8, respectively. The two for-
mer bond angles are similar to the values in Cu(sal2tn)
[79.8(4) and 95.5(4)8], but on the basis of the two latter
bond angles [(171.9(3) and 171.8(3)8] we can conclude
that the coordination geometry around copper in the title
complex is near to square-planar in comparison to
Cu(sal2tn), which has corresponding values of 159.7(4) and
158.2(4)8, respectively. The central carbon atom in the tri-
methylene diamine chelate ring (labelled C(1) and C(19);
see Fig. 1) is disordered over two positions, one of which is
above and another below the coordinationplane. Thedisorder
is quite common and is observed, for example, in some of the
transition metal complexes with Schiff base ligands [14].
Complex III has been prepared and recrystallized in eth-
anol solution. The elemental analysis confirms the formula-
tion of the complex. Recrystallization of complex III for
preparing a single crystal was carried out in ethanol–chloro-
form. The crystal structure shows the presence of a CHCl3
On the basis of these results it can be deduced that in
complexes I, II and III the Schiff bases are coordinated to
copper atom as tetradentate ONNO ligands. The IR spectra
of complex IV shows no shift for N–H bond in comparison
Table 3
Physical and characterization data for complexes
Compound
I
II
III
IV
Formula
C28H22CuN6O2
94
C32H22CuN6O2
92
C29H24CuN6O2
94
C30H27CuN7O2
92
Yield (%)
IR (cmy1
)
n(C_N)
n(N–H)
1630
1600
1605
1625
3250
Anal.: found (calc.) (%)
C
H
N
62.3 (62.50)
4.0 (4.09)
15.5 (15.62)
65.4 (65.58)
3.7 (3.75)
14.1 (14.34)
62.8 (63.09)
4.3 (4.35)
15.1 (15.23)
61.8 (62.01)
4.6 (4.65)
16.7 (16.88)
Friday Mar 31 02:15 PM
StyleTag -- Journal: POLY (Polyhedron) Article: 3331
Khandar
