Crystal structure and spectroscopic studies of bis[N-(2-iodo)-naphthaldiminato]copper(II)

Article abstract of DOI:10.1016/S0022-2860(02)00188-6

The Schiff base complex bis[N-(2-iodo)-naphthaldiminato]copper(II) [Cu(C₁₇H₁₁NOI)₂] (1) has been studied by elemental analysis, IR techniques and the structure of the compound has been examined crystallography. The compound 1 crystallizes in the monoclinic space group P2₁/c with a = 8.229(2) ?, b = 15.840(4) ?, c = 11.389(3) ?, β = 104.49(2)° (R = 0.053 for 2507 reflections [1 > 2σ(I)]). It has crystallographic inversion symmetry. Two bidentate Schiff base ligand 1 coordinate to the Cu atom in a square-planar arrangement. The Cu-N and Cu-O distances are 1.990(2) and 1.896(2) ?, respectively.

Full text of DOI:10.1016/S0022-2860(02)00188-6

Journal of Molecular Structure 641 (2002) 35–40
www.elsevier.com/locate/molstruc
Crystal structure and spectroscopic studies of
bis[N-(2-iodo)-naphthaldiminato]copper(II)
¨
H. Unver
*
ˇ
Department of Physics, Faculty of Sciences, Ankara University, Tandogan, TR-06100 Ankara, Turkey
Received 1 August 2001; accepted 17 April 2002
Abstract
The Schiff base complex bis[N-(2-iodo)-naphthaldiminato]copper(II) [Cu(C17H11NOI)2] (1) has been studied by elemental
analysis, IR techniques and the structure of the compound has been examined crystallography. The compound 1 crystallizes in
ꢀ
ꢀ
ꢀ
the monoclinic space group P21/c with a ¼ 8:229ð2Þ A; b ¼ 15:840ð4Þ A; c ¼ 11:389ð3Þ A; b ¼ 104:49ð2Þ8 (R ¼ 0:053
for 2507 reflections [I . 2s(I )]). It has crystallographic inversion symmetry. Two bidentate Schiff base ligand 1 coordinate
˚
to the Cu atom in a square–planar arrangement. The Cu–N and Cu–O distances are 1.990(2) and 1.896(2) A, respectively.
q 2002 Elsevier Science B.V. All rights reserved.
Keywords: Schiff base ligand; Complex; Spectroscopic study; Crystal structure; Inversion symmetry
1. Introduction
these essentially planar molecules. In order to
investigate distortions in the geometry and the
mode of packing, in this paper, we have
determined the structures of the complexes CuL2,
where L is N-(2-iodo)-naphthaldimine.
2-Hydroxy Schiff base ligands and their cop-
per(II) complexes play a major role in both the
synthesis and structural research [1]. Schiff base
complexes have continued to play the role of one
of the most important stereochemical models in
main group and transition metal coordination
chemistry with their easy preparation diversition
and structural variation [2]. There have been many
crystal structure determinations of 2:1 complexes
between copper(II) and planar bidentate ligand (N-
(2-iodo)-naphthaldimine) with two O and two N
donor atoms. The geometry of the immediate
coordination sphere is usually planar. An
additional point of interest is the packing of
2. Experimental
2.1. Reagent and technique
2-Hydroxy-1-naphthaldehyde, 2-iodoaniline,
methanol and CDCl3 were purchased from Merck
(Germany). Ethanol and acetonitrile were purchased
from Aldrich Chemical Co. Melting point was
measured on a Gallonkamp apparatus using a
capillary tube. The elemental analyses were per-
formed on a LECO CHNS-932 C-, H-, N-analyser.
Infrared absorption spectra were obtained from a
*
Corresponding author.
E-mail address: unver@science.ankara.edu.tr
0022-2860/02/$ - see front matter q 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-2860(02)00188-6

¨
H. Unver / Journal of Molecular Structure 641 (2002) 35–40
36
Fig. 1. Reaction scheme and chemical structure.
Mattson 1000 FTIR spectrometer in KBr discs and
reported in cm21. Proton (400 MHz) NMR spectra
were recorded with a Bruker DPX FT-NMR
spectrometer (CDCl3 as internal standard).
yellow crystals were harvested and dried in vacuo.
[Cu(CH3COO)2]·H2O (0.001 mol, 0.199 g) in
methanol (50 ml) and N-(2-iodo)-naphthaldimine
(0.002 mol, 0.744 g) in acetonitrile (75 ml) were
mixed and heated at 333 K for 1 h. The solution was
filtered and the filtrate kept in a beaker at 277 K for
crystallization. Black crystals started appearing after
3–4 days and were then collected by filtration,
0.609 g (65%) yields (Fig. 1). Found: C, 50.10; H,
2.81; N, 3.23, C34H22N2O2I2Cu; C, 50.49; H, 2.72; N,
3.47%. Crystals suitable for X-ray diffraction were
obtained by slow evaporation from a saturated ethanol
solution.
2.2. Preparation of bis[N-(2-iodo)-
naphthaldiminato]copper(II)
N-(2-iodo)-Naphthaldimine was prepared by con-
densation of 2-hydroxy-1-naphthaldehyde (0.01 mol,
1.72 g) and 2-iodoaniline (0.01 mol, 2.19 g) in 100 ml
of ethanol. The reaction mixture was stirred for 4 h
and then placed in a freezer for 18 h. The yellow
precipitate was collected by filtration and then washed
with cold ethanol, mp 150 8C, 3.01 g (77%) yields.
Found: C, 54.65; H, 3.44; N, 3.65, C17H12NOI: C,
54.71; H, 3.24; N, 3.75%. IR (KBr, cm21): n(Ar–H)
3062–3064 m, n(CyN) 1624 s, n(CyC) 1610 s, n(C–
2.3. X-ray structure determination
A
crystal
with
dimensions
of
0.10 £ 0.15 £ 0.05 mm3 for 1 was mounted on a
Rigaku AFC7-S diffractometer employing graph-
ite-monochromatized Mo Ka radiation ðl ¼
1
O) 1326 s. H NMR (CDCl3); d ppm, 15.24 (s, 1H,
NH); 9.32 (s, 1H, CHyN); 6.82–8.14 (m, 12H, Ar–
H). MS (EI) m/z: (%) 373 (Mþ) 100 base peak; 374
(M þ 1)þ 17.5; 375 (M þ 2)þ 1.7; 372 (M 2 1)þ 87;
356 (M–OH) 12.1; 204 (M–C6H5Iþ) 1.1; 128
(C10Hþ8 ) 3.8; 246 (M–I) 10.95; 77 (M–C6Hþ5 ) 2.92
and 76 (M–C6Hþ4 ) 5.5 [3]. After recrystallization,
ꢀ
0:71073 AÞ [4]. Experimental conditions of 1 are
summarized in Table 1. Cell parameters were
determined by the least-squares refinement on the
setting angles of 25 reflections [10.48 , u , 19.28]
for 1 carefully centred on the diffractometer.

¨
H. Unver / Journal of Molecular Structure 641 (2002) 35–40
37
Table 1
Table 2
Crystal and experimental data
Final atomic coordinates and equivalent isotropic thermal par-
ameters for non-hydrogen atoms
Compound
C34H22N2O2I2Cu
2
Beq (A )
˚
Color/shape
Black/prismatic
807.88
Atom
x
y
z
Formula weight
Crystal system
Space group
Cell constants
Monoclinic
P21/c
Cu1
I1
0.0000(0)
0.0000(0)
0.0000(0)
0.1906(1)
2.14(2)
5.97(2)
3.15(4)
2.39(4)
3.05(6)
3.24(5)
4.37(7)
3.72(6)
3.60(7)
5.11(9)
4.82(7)
3.58(6)
2.91(5)
4.62(7)
3.19(6)
2.70(5)
6.80(9)
4.21(7)
5.51(9)
4.78(8)
3.14(5)
20.2636(1)
20.1508(3)
20.1268(2)
20.2467(3)
20.3134(3)
20.4221(4)
20.4634(2)
20.5799(3)
20.6140(4)
20.5466(2)
20.4232(2)
20.3911(3)
20.2829(4)
20.2303(3)
20.1010(3)
20.0162(5)
0.0169(3)
20.0540(2)
20.0033(9)
0.0953(1)
0.0572(1)
0.0430(2)
0.1016(2)
0.1766(2)
0.2341(2)
0.3075(2)
0.3289(1)
0.2708(1)
0.1933(2)
0.1319(2)
0.1427(2)
0.1135(1)
0.1976(3)
0.2055(2)
0.1467(2)
0.0749(2)
0.0576(2)
ꢀ
a ¼ 8:229ð2Þ A
O1
20.1560(2)
0.0484(1)
ꢀ
b ¼ 15:840ð4Þ A
N1
ꢀ
c ¼ 11:389ð3Þ A
C1
20.2095(2)
20.3377(2)
20.4052(3)
20.3548(2)
20.4262(2)
20.3825(3)
20.2638(2)
20.1846(2)
20.2324(2)
20.1594(3)
20.0302(2)
0.1747(2)
b ¼ 104:49ð2Þ8
C2
3
˚
Cell volume
Formula units/unit cell
Dx
1437.3(6) A
C3
4
C4
1.867 g cm23
1.020 mm21
Rigaku AFC7-S/v–2u
C5
m (Mo Ka)
Diffractometer/scan
l (Mo Ka)
C6
C7
˚
0.71073 A
C8
Crystal size
T
0.10 £ 0.15 £ 0.05 mm3
C9
293 K
3
C10
C11
C12
C13
C14
C15
C16
C17
Standard reflections
F (000)
782
Range of h, k, l
0 # h # 9
0 # k # 18
213 # l # 13
2812
0.2205(3)
0.3412(3)
20.0203(4)
20.1006(3)
20.1346(3)
0.4217(2)
Number of reflections measured
0.3765(3)
Number of reflections used
2507
0.2548(2)
Number of parameters
185
P P
i
Beq ¼ ð8p2=3Þ
j Uijaipajpðai·ajÞ:
R
0.053
Rw
0.112
Goodness-of-fit
(D/s)max
(D/r)max
(D/r)min
1.025
0.012
ORTEP view of the molecular structure of 1 is
given in Fig. 2 [8].
23
˚
23
˚
0.56 e A
20.40 e A
Standard reflections (110, 200, 210) were
measured every 150 reflections. A total of 2812
reflections was recorded, with indices of hmin ¼ 0;
3. Results and discussion
3.1. Spectroscopic study
hmax ¼ 9; kmin ¼ 0; kmax ¼ 18; lmin ¼ 213; lmax
¼
13: Data reduction and corrections for absorption
and crystal decomposition (1.2%) were carried out
using the TEXAN Single Crystal Structure Anal-
ysis Software [5]. The structure was solved by
SHELXS-97 [6] and refined with SHELXL-97 [7].
The positions of H atoms bonded to C atoms were
The IR spectrum of the N-(2-iodo)-naphthaldimine
reveals a band at 3415 cm21 due to n(O–H) [9]. This
band is absent in the title copper(II) complex (1),
indicating coordination through deprotonated pheno-
lic OH group. The n(CyN) band appears at 1602–
1605 cm21 in the metal complex as compared to that
at 1624 cm21 in Schiff base. This decrease (19–
22 cm21) indicates the coordination of nitrogen of
azomethine group with the metal ion. The strong
ligand band at 1326 cm21 appears at 1309 cm21 in the
complex, thus showing a shift towards lower regions
by 17 cm21. This band is characteristic of n(C–O)
and its shift further supports the formation of the M–
O bond [10–12]. The title compound 1 also show
˚
calculated (C–H distance 0.93 A), and included in
the structure factor calculation using a riding
model. H atom displacement parameters were
restricted to be 1.2 Ueq of the parent atom.
Fractional atomic coordinates and equivalent
isotropic thermal parameters for non-hydrogen
atoms are given for in Table 2. Bond distances
and bond angels for 1 are listed in Table 3. An

¨
H. Unver / Journal of Molecular Structure 641 (2002) 35–40
38
Table 3
˚
Bond lengths (A), angles (8) and torsion angles (8)
Cu1–O1
I1–C17
N1–C11
C1–C2
1.896(2)
Cu1–N1
O1–C1
1.990(2)
1.293(3)
1.431(3)
1.378(4)
1.398(4)
1.398(3)
1.370(3)
1.395(3)
1.437(4)
1.348(3)
1.394(5)
1.372(4)
2.097(2)
1.306(3)
1.443(3)
1.382(4)
1.421(4)
1.322(5)
1.495(3)
1.434(4)
1.534(5)
1.339(5)
1.351(5)
N1–C12
C1–C10
C3–C4
C2–C3
C4–C5
C4–C9
C5–C6
C6–C7
C7–C8
C8–C9
C9–C10
C12–C13
C13–C14
C15–C16
C10–C11
C12–C17
C14–C15
C16–C17
O1–Cu1–N1
Cu1–N1–C11
C11–N1–C12
O1–C1–C10
C1–C2–C3
90.9(1)
122.9(2)
118.7(2)
127.7(2)
119.2(2)
120.6(3)
120.5(2)
121.2(3)
118.2(2)
119.9(2)
120.6(3)
119.8(3)
117.1(2)
119.6(3)
126.3(3)
120.7(3)
118.6(2)
Cu1–O1–C1
Cu1–N1–C12
O1–C1–C2
126.8(2)
118.4(1)
113.2(2)
119.1(2)
122.2(3)
118.9(2)
121.7(3)
119.3(2)
118.7(2)
121.4(2)
119.0(3)
127.7(2)
123.0(2)
112.8(3)
118.6(3)
119.3(2)
121.9(2)
C2–C1–C10
C2–C3–C4
C3–C4–C5
C3–C4–C9
C5–C4–C9
C4–C5–C6
C5–C6–C7
C6–C7–C8
C7–C8–C9
C4–C9–C8
C4–C9–C10
C1–C10–C9
C9–C10–C11
N1–C12–C13
C13–C12–C17
C13–C14–C15
C15–C16–C17
I1–C17–C16
C8–C9–C10
C1–C10–C11
N1–C11–C10
N1–C12–C17
C12–C13–C14
C14–C15–C16
I1–C17–C12
C12–C17–C16
N1–Cu1–O1–C1
O1–Cu1–N1–C12
Cu1–O1–C1–C10
C12–N1–C11–C10
Cu1–N1–C12–C17
C11–N1–C12–C17
C10–C1–C2–C3
O1–C1–C10–C11
C2–C1–C10–C11
C2–C3–C4–C5
22.1(2)
162.4(2)
211.9(4)
2175.2(3)
260.8(3)
120.1(3)
24.9(4)
29.3(5)
174.0(2)
2178.0(3)
2176.2(3)
175.5(2)
25.9(4)
24.4(5)
25.0(3)
2175.8(2)
2170.0(3)
11.6(4)
O1–Cu1–N1–C11
Cu1–O1–C1–C2
Cu1–N1–C11–C10
Cu1–N1–C12–C13
C11–N1–C12–C13
O1–C1–C2–C3
218.6(2)
164.9(2)
5.8(4)
113.4(2)
265.7(3)
178.0(2)
179.3(3)
2.6(4)
O1–C1–C10–C9
C2–C1–C10–C9
C1–C2–C3–C4
3.3(4)
C2–C3–C4–C9
0.6(4)
C3–C4–C5–C6
C9–C4–C5–C6
5.2(4)
C3–C4–C9–C8
C3–C4–C9–C10
C5–C4–C9–C10
C5–C6–C7–C8
23.0(4)
175.7(3)
4.3(4)
C5–C4–C9–C8
C4–C5–C6–C7
C6–C7–C8–C9
C7–C8–C9–C4
5.8(3)
C7–C8–C9–C10
C4–C9–C10–C11
C8–C9–C10–C11
C9–C10–C11–N1
C17–C12–C13–C14
N1–C12–C17–C16
C13–C12–C17–C16
C13–C14–C15–C16
C15–C16–C17–I1
C4–C9–C10–C1
C8–C9–C10–C1
C1–C10–C11–N1
N1–C12–C13–C14
N1–C12–C17–I1
C13–C12–C17–I1
C12–C13–C14–C15
C14–C15–C16–C17
C15–C16–C17–C12
1.3(4)
2177.1(3)
12.0(5)
2174.1(3)
29.6(3)
176.3(2)
20.8(5)
4.4(5)
2176.6(3)
0.4(5)
176.5(2)
2.5(4)
21.5(5)
2178.9(3)
24.9(5)

¨
H. Unver / Journal of Molecular Structure 641 (2002) 35–40
39
Fig. 2. The molecular structure of the title compound 1. The displacement ellipsoids are plotted at the 50% probability level [8].
some new bands at 540–500 and 390–340 cm21
which can be assigned to n(Cu–N) and n(Cu–O),
respectively [13].
reported X-ray crystal structures of naphthalenic
Schiff base-copper compounds [14,15].
The title compound bis[N-(2-iodo)-naphthaldimi-
nato]copper(II), [Cu(C17H11NOI)2] has crystallo-
graphic inversion symmetry. The coordination of the
copper(II) ion is necessarily planar by symmetry. A
strictly planar or slightly distorted trans configuration
is a characteristic for transition metal complexes of
copper(II) with a CuN2O2 coordination sphere. In the
title compound, the copper(II) ion is bonded to the O
and N donor atoms of the two ligand molecules in a
trans arrangement. The Cu–N and Cu–O distances
3.2. Crystallographic study
Because of their preparative accessibility and
structural variability, a great number of Schiff base
complexes of copper have been the subject of
extensive studies [2]. Despite this, there are a few
Table 4
˚
Bond lengths (A) in some similar copper(II) complexes
˚
are 1.990(2) and 1.896(2) A, respectively. The O–
Cu–N angle is 90.9(1)8. The Cu–N distances range
˚
from 1.930 to 2.020 A, while the Cu–O distances
C–O
CyN
Cu–N
Cu–O
˚
have values between 1.870 and 1.920 A in copper
Ia
1.293(6)
1.318(6)
1.303(5)
1.323(4)
1.296(7)
1.293(3)
1.295(6)
1.291(6)
1.288(5)
1.279(4)
1.296(6)
1.306(3)
1.990(4)
2.019(4)
1.965(3)
1.939(3)
1.980(5)
1.990(2)
1.880(4)
1.879(4)
1.889(3)
1.883(2)
1.878(4)
1.896(2)
IIb
IIIc
IVd
Ve
Vf
complexes [16–20]. The Cu–N and Cu–O values in
the title compound agree with those in other
complexes. In Table 4 the bond lengths of several
complexes of N-substituted salicylaldimines and
naphthaldimines are compared with our values. The
copper(II) ion is in a pseudo-octahedral environment
if iodine is included in the description. The non-
˚
bonded Cu· · ·I distance is 3.536(1) A. The title
molecule is not planar; the copper(II) ion lies
˚
0.157(1) A below the plane formed by the Cu1, O1,
a
Bis[N-(2-bromo-4-methylphenyl)-naphthaldiminato]copper (II)
[16].
b
Bis[N-(4-bromophenyl)-salicylaldimine]copper (II) [17].
c
{2-[2-(Salicylideneaminometyl)phenyl-iminometyl]pheno-
lato(2-)-N,N0,O,O0}-copper (II) [18].
d
[N,N0-Bis(salicylidene)-1,2-diimino-2-methylpropane]cop-
per(II) [19].
e
C10, C11 and N1 atoms. The two Schiff base
moieties, A (O1, C1–C11) and B (N1, C12–C17,
I1), are inclined at an angle of 56.9(3)8 with respect to
Bis[2-[N-(2-chlorophenyl)formimidayl]-1-naphtholato]-
(6Cl)copper(II) [20].
f
Present work.

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H. Unver / Journal of Molecular Structure 641 (2002) 35–40
40
[7] G.M. Sheldrick, SHELXL-97, Program for the refinement of
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(1998) 757.
one another, which is mainly the twist about N1–C12
[66.5(2)8].
Discrete monomeric molecules are held together in
the crystal by van der Waals interactions. The
minimum distances between two non-H atoms in
neighbouring molecules are C2· · ·C11 and Cu1· · ·C10
[10] P.K. Mahapatra, B.K. Mahapatra, S. Curu, J. Inorg. Nucl.
Chem. 39 (1977) 2281.
˚
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