Nickel(II) and iron(II) complexes with 1-(2(4)-chlorophenyl) benzothiazolylformazans

Article abstract of DOI:10.1134/S1070328410030085

Novel nickel(II) and iron(II) complexes with 1-(2(4)-chlorophenyl) benzothiazolylformazans L and L' of the general formulas ML₂ and ML'₂ were obtained. According to X-ray diffraction data, the coordination polyhedron MN₆ is a distorted octahedron. This geometry of the coordination polyhedron is determined by the nature of the complexing metal.

Full text of DOI:10.1134/S1070328410030085

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2010, Vol. 36, No. 3, pp. 213–219. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © I.G. Pervova, P.A. Slepukhin, A.V. Zaidman, G.N. Lipunova, I.N. Lipunov, 2010, published in Koordinatsionnaya Khimiya, 2010, Vol. 36, No. 3,
pp. 214–220.
Nickel(II) and Iron(II) Complexes
with 1ꢀ(2(4)ꢀChlorophenyl)benzothiazolylformazans
I. G. Pervovaa, P. A. Slepukhinb, *, A. V. Zaidmana, G. N. Lipunovab, and I. N. Lipunova
aUral State University of Forestry Engineering, Yekaterinburg, Russia
bPostovskii Institute of Organic Chemistry, Ural Division, Russian Academy of Sciences, Yekaterinburg, Russia
*Eꢀmail: slepukhin@ios.uran.ru
Received May 27, 2009
Abstract—Novel nickel(II) and iron(II) complexes with 1ꢀ(2(4)ꢀchlorophenyl)benzothiazolylformazans L
and L' of the general formulas ML2 and ML' were obtained. According to Xꢀray diffraction data, the coorꢀ
2
dination polyhedron MN6 is a distorted octahedron. This geometry of the coordination polyhedron is deterꢀ
mined by the nature of the complexing metal.
DOI: 10.1134/S1070328410030085
A search for novel types of ligand systems is a priorꢀ
ity area in coordination chemistry. Of particular interꢀ
est is the study of complexation reactions of hetarylꢀ
formazans containing different numbers of coordinaꢀ
tively active N, O, S, etc. atoms. The broad scope of
such polydentate ligand molecules can be used for tarꢀ
geted design of metal complexes. The tendency toward
chelation of metal atoms by forming stable chelate
rings is especially pronounced for formazans containꢀ
ing hydroxy, carboxy, methoxy, and mesylamido
groups in the orthoꢀpositions of aryls at the N1 (N5)
atoms [1–5].
EXPERIMENTAL
Synthesis of compound L. A solution of a diazonium
salt prepared from oꢀchloroaniline (1.53 g, 0.012 mol)
and NaNO2 (0.9 g, 0.013 mol) was slowly added at
~0 to a stirred solution of butyraldehyde benzothiaꢀ
zolꢀ2ꢀylhydrazone (2.6 g, 0.011 mol) in isopropyl
alcohol (30 ml) and concentrated HCl (2 ml). The
reaction mixture was alkalified with 2 N NaOH to
pH 8–9, kept for 3 h, acidified with acetic acid to
pH 7, and left at room temperature overnight. The
precipitate that formed was filtered off, washed with
water, dried in air, and recrystallized from ethanol;
°
С
Coordinatively active Cl atoms in organic ligands
have been reported in [6–8] to take an active part in
the formation of metal complexes, which allows the
synthesis of a wide range of complexes with different
coordination polyhedron geometries and, conseꢀ
quently, different physicochemical properties [6–8].
T
m = 80–81°C,
Rf = 0.82 (ethyl acetate–heptane, 1 : 1),
λmax = 440 nm.
For C18H18ClN5S
anal. calcd., %:
Found, %:
⋅
0.5 H2O
C, 56.77;
C, 57.15;
H, 4.89;
H, 5.13;
S, 8.42.
S, 8.63.
To extend the range of ligands employed for the
preparation of new metal complexes, we obtained
nickel(II) and iron(II) complexes with 1ꢀ(2ꢀchloꢀ
Compound L' was synthesized in a similar way,
except that the reaction mixture was alkalified for 1 h;
Tm = 115–116°C, Rf 0.84 (ethyl acetate–heptane,
1 : 1), λmax = 445 nm.
rophenyl)ꢀ3ꢀ(
zan L ( and II, respectively) and an iron(II) complex
with 1ꢀ(4ꢀchlorophenyl)ꢀ3ꢀ( ꢀbutyl)ꢀ5ꢀ(benzothiaꢀ
nꢀbutyl)ꢀ5ꢀ(benzothiazolꢀ2ꢀyl)formaꢀ
I
n
zolꢀ2ꢀyl)formazan L' (III). Structures I–III were
For C18H18ClN5S
examined by Xꢀray diffraction.
anal. calcd., %:
Found, %:
C, 58.14;
C, 57.93;
H, 4.85;
H, 4.78;
S, 8.61.
S, 8.41.
Because the properties of formazan ligands vary
more widely than do the properties of metals, the
influence of organic molecules on the formation of
metal complexes is relatively more diversified and, in
Complex I was obtained as described in [9]. A hot
some cases, more stronger. However, the stabilizing aqueous solution of nickel acetate (analytical or highꢀ
effect of a complexing metal on a particular formazan purity grade, 5 mmol) was added to a hot solution of
tautomer is also of research interest since the physicoꢀ compound L (0.01 mol) in acetone. The solution
chemical properties and reactivities of metal comꢀ immediately changed in color. The reaction mixture
plexes largely depend on the stereochemistry of the was refluxed for 10 min and cooled. The precipitate
coordination polyhedron.
that formed was filtered off, washed with water, dried
213

214
PERVOVA et al.
ForC36H34Cl2FeN10S2
A
1
(а)
anal. calcd., %:
Found, %:
C, 54.20;
C, 54.34;
H, 4.30;
H, 4.09;
N, 17.56.
N, 17.39.
0.20
2
0.15
0.10
0.05
0
Crystals of complexes I–III were grown by roomꢀ
temperature crystallization from acetone.
Xꢀray diffraction analysis of complexes I–III was
carried out on an Xcalibur 3 automated singleꢀcrystal
diffractometer fitted with a CCD detector according
to a standard procedure (Мо
К radiation, graphite
α
monochromator,
absorption correction was applied analytically [10].
Structures III were solved and refined with the
ω
scan mode, scan step
1
°
). An
I–
SHELX program package [11]. Nonꢀhydrogen atoms
were located by the direct methods and refined by the
fullꢀmatrix leastꢀsquares method on F 2 mostly in the
anisotropic approximation. Some terminal atoms in
the butyl substituents were refined isotropically
because of a complicated disordering of their positions
(to do this, we added the function ISOR 0.01 to the
structure refinement instruction in the SHELXL proꢀ
gram). Hydrogen atoms were calculated geometrically
and refined in the riding model with dependent therꢀ
mal parameters. Crystallographic parameters and the
data collection statistics for structures I–III are sumꢀ
marized in Table 1. Selected bond lengths and bond
angles are given in Table 2.
The CIF files containing comprehensive informaꢀ
tion on structures I–III have been deposited with the
400
500
600
700
800
, nm
λ
A
1
(b)
0.25
0.20
0.15
0.10
0.05
0
2
400
500
600
700
800
, nm
Cambridge Crystallographic Data Collection
(nos. 747455, 747456, and 747457, respectively;
http://www.ccdc.cam.ac.uk/data_request/cif).
λ
Fig. 1. Electronic absorption spectra of spectrophotometꢀ
ric titration of 1ꢀ(2ꢀchlorphenyl)ꢀ3ꢀ( ꢀbutyl)ꢀ5ꢀ(benꢀ
zothiazolꢀ2ꢀyl)formazan with (a) nickel(II) acetate and
(b) iron(II) chloride: (
corresponding metal complex;
n
RESULTS AND DISCUSSION
1) the initial formazan and (
2
) the
–5
–1
c
= 3
×
10 mol l
,
c
=
f
salt
We studied the complexing properties of 1ꢀ(2(4)ꢀ
–3
–1
1 × 10 mol l .
chlorophenyl)ꢀ3ꢀ(
mazans by spectrophotometric titration. During the
titration of a solution of ꢀchlorophenyl formazan in
acetone with aqueous nickel(II) acetate, the intensity
of the absorption band of the free formazan at λmax
nꢀbutyl)ꢀ5ꢀ(benzothiazolꢀ2ꢀyl)forꢀ
o
in air, and recrystallized from acetone; Tm = 196–
198°C, λmax = 605 nm.
=
440 nm gradually decreases and a new band of its comꢀ
plex appears at λmax = 600–610 nm (Fig. 1a). The
spectral pattern shows two isosbestic points suggesting
For C36H34Cl2N10NiS2
anal. calcd., %:
Found, %:
C, 54.00;
C, 54.50;
H, 4.28;
H, 4.25;
N, 17.50.
N, 16.88.
sequential formation of metal complex
formula is NiL2). The bathochromic shift is 165 nm.
When titrating 1ꢀ(2ꢀchlorophenyl)ꢀ3ꢀ( ꢀbutyl)ꢀ5ꢀ
I (its calculated
n
Complex II was obtained in a similar way, except
that FeCl2 was used; m = 198–200°C.
(benzothiazolꢀ2ꢀyl)formazan with aqueous FeCl2, we
observed no pronounced absorption peak for complex
III (Fig. 1b), although the intensity of the absorption
band of the free formazan decreased. The calculated
formula for an iron complex with the formazan is
FeL2.
T
For C36H34Cl2FeN10S2
anal. calcd., %:
C, 54.20;
C, 54.55;
H, 4.30;
H, 4.32;
N, 17.56.
N, 17.13.
Found, %:
The electronic absorption spectra of complexes
I⎯III isolated in the crystalline state are identical with
m = 198– their spectra recorded during spectrophotometric
Complex III was obtained as described for complex
II, except that compound L' was used;
T
200°C.
titration.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 36
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2010

NICKEL(II) AND IRON(II) COMPLEXES
215
Table 1. Selected crystallographic parameters and the data collection statistics for structures I–III
Value
Parameter
I
II
III
M
800.46
Plate
797.60
Prism
797.60
Prism
Crystal shape
Crystal size, mm
Crystal color
Temperature, K
Crystal system
Space group
0.25
×
0.12
×
0.02
0.14
×
0.10
×
0.06
0.28
×
0.17
×
0.11
Black
Dark blue
120(2)
Black
295(2)
Triclinic
295(2)
Triclinic
Monoclinic
P
21/n
P1
P1
Unit cell
:
a
, Å
, Å
10.1375(18)
11.003(3)
18.881(2)
97.882(17)
93.513(11)
116.627(19)
1846.9(6)
2
10.1860(8)
22.0990(16)
32.775(4)
90
10.4816(6)
13.0973(13)
15.3073(8)
95.264(8)
104.050(5)
112.765(7)
1838.8(2)
2
b
c
, Å
α
,
deg
deg
deg
β
,
98.774(8)
90
γ,
V
Z
, Å3
7291.4(12)
8
ρcalcd, g/cm3
1.439
1.453
1.441
μ
, mm–1
(000)
0.825
0.718
0.711
F
828
3296
824
θ scan range, deg
2.66–26.37
14797
2.64–26.38
47571
2.96–28.28
20917
Number of measured reflections
Number of independent reflections
(
Rint
)
7198 (0.0473)
3278
14714 (0.0908)
6481
8793 (0.0256)
5476
Number of reflections with
I
> 2σ
(I)
Coverage degree
(for θmax), %
95.3
98.4
96.5
GOOF on F2
0.934
0.919
1.026
R1
wR2
R1 for all reflections
wR2 for all reflections
Δρmin/max
Å–3
(
I
> 2
σ
(
I
))
0.0474
0.0455
0.0376
(
I
> 2
σ
(
I
))
0.0519
0.0524
0.0851
(
)
0.1255
0.1337
0.0702
(
)
0.0567
0.0574
0.0898
,
e
0.405/–0.343
0.564/–0.482
0.396/–0.403
Before considering the crystal structures of comꢀ plexes (Figs. 2–4). In reactions with NiAc2 and FeCl2
,
plexes III, we should note that they are similar in the formazan molecules act as tridentate ligands to
I
⎯
some essential properties but seriously differ in others.
The differences are associated with their molecular
packing. For instance, complexes I and III crystallize
in triclinic crystal systems with very different unit cell
'
give metal complexes ML2 and ML2 . The coordinaꢀ
tion polyhedron MN6 is a distorted octahedron.
Either formazan molecule forms a chelate unit
consisting of two fiveꢀmembered chelate rings. The
unit is nearly planar: the deviations of the atoms from
the meanꢀsquare plane do not exceed 0.15 Å. The
dihedral angles between the chelate ring planes of two
parameters. The crystals of complex II are monoclinic
(space group
P21/n) and consist of two crystallographꢀ
ically independent molecules IIa and IIb. Structures
I–III are similar in general organization of the comꢀ ligands is 77.1
°
for complex
I,
85.8
°
and 84.7 for the
°
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 36
No. 3
2010

216
Table 2. Bond lengths and bond angles in the coordination polyhedra of complexes I–III (M = Ni (I) and Fe (II, III))
, A
II
PERVOVA et al.
d
Bond
I
III
IIа
IIb
M(1)–N(8)
M(1)–N(3)
M(1)–N(5)
M(1)–N(10)
M(1)–N(6)
M(1)–N(1)
1.978(3)
1.975(2)
2.154(2)
2.119(3)
2.078(3)
2.083(2)
1.868(2)
1.877(2)
1.896(2)
1.907(3)
1.983(2)
1.995(3)
1.873(2)
1.863(2)
1.897(3)
1.900(3)
1.980(3)
1.998(3)
1.8690(16)
1.8778(15)
1.9294(14)
1.9493(17)
1.9925(16)
1.9935(15)
ω
, deg
Angle
I
II
III
N(8)M(1)N(3)
N(8)M(1)N(5)
N(3)M(1)N(5)
N(8)M(1)N(10)
N(3)M(1)N(10)
N(5)M(1)N(10)
N(8)M(1)N(6)
N(3)M(1)N(6)
N(5)M(1)N(6)
N(10)M(1)N(6)
N(8)M(1)N(1)
N(3)M(1)N(1)
N(5)M(1)N(1)
N(10)M(1)N(1)
N(6)M(1)N(1)
172.96(12)
107.58(9)
74.95(10)
75.03(11)
98.04(11)
103.76(10)
76.81(12)
110.11(11)
85.08(9)
178.32(12)
100.83(10)
78.56(11)
78.58(11)
99.92(11)
97.45(11)
78.16(11)
103.37(11)
90.13(10)
156.51(11)
102.40(11)
78.29(11)
156.58(11)
90.04(10)
91.72(10)
179.38(7)
101.04(7)
78.43(7)
78.66(7)
101.74(7)
103.13(7)
78.67(7)
101.01(7)
90.39(6)
155.43(7)
102.19(6)
78.32(6)
156.43(7)
85.37(7)
90.27(6)
151.83(11)
101.27(10)
76.89(10)
150.85(10)
87.44(9)
97.70(9)
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 36
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NICKEL(II) AND IRON(II) COMPLEXES
217
C(21)
C(18)
C(22)
C(23)
C(20)
C(17)
C(19)
C(16)
C(15)
C(10)
C(11)
C(24)
S(2)
C(13)
N(4)
N(3)
C(12)
C(8)
N(5)
C(9)
C(14)
N(6)
C(25)
N(2)
C(7)
N(1)
Ni(1)
N(7)
Cl(1)
S(1)
C(1)
C(6)
Cl(2)
C(5)
N(8)
C(2)
C(3)
C(4)
N(9)
C(26)
C(32)
N(10)
C(33)
C(31)
C(36)
C(27)
C(34)
C(28)
C(35)
C(29)
C(30)
Fig. 2. Structure I (the hydrogen atoms are omitted in Figs. 2–4).
independent molecules of complex II, and 81.6
°
for rophenyl substituent has no substantial effect on the
geometry of the coordination polyhedron.
complex III
.
The terminal chlorophenyl substituents in the
The geometry of the coordination polyhedron
depends on the complexing metal, which is evident
from a comparison of the bond lengths in the coordiꢀ
complexes make large angles (from 50
formazan plane, which breaks their conjugation with
the chelate ring. The Cl atoms in the ꢀchlorophenyl
substituents of complexes and II have different oriꢀ
entations. In nickel complex , they are spatially close
(interatomic distance ~4 Å). In complex II, they are
rotated from each other, while the ꢀH atoms in the
°
to 75
°
) with the
о
nation polyhedra of complexes I–III.
I
I
According to these data, the shortest M(II)–N
bonds in all the complexes are the bonds between the
metal atom and the N(3) and N(8) atoms of the forꢀ
mazan fragment. The longest M(II)–N (1,6) bonds in
complexes II and III are the bonds between the metal
atom and the N(1) and N(6) atoms of the heterocycle;
o
chlorophenyl substituent are spaced at ~2.8–2.9 Å. At
the same time, the Cl atoms approach the conjugation
plane of the benzothiazole ring (from 3.5 to 3.7 Å).
Because of this, the electron shell of the Cl atom can
in complex I, the nickel atom forms the longest bonds
come into contact with the ꢀelectronic system of the
π
to the formazan N(5) and N(10) atoms bearing the
chlorophenyl substituents. The scatter in the Fe–N
bond lengths for the coordination polyhedra of comꢀ
plexes II and III amounts to 0.15 Å (Table 2). This is
because different atoms of the tridentate ligand differꢀ
ently interact with the central atom. The differences in
the lengths of the corresponding bond pairs in the
coordination polyhedra of iron complexes II and III
do not exceed 0.05 Å (mostly, < 0.03 Å) and can be
attributed to different experimental temperatures
(Table 1) and a random error during the experiment.
heterocycle. Apparently, such a contact additionally
stabilizes this conformation of the complex. The oriꢀ
entations of the Cl atoms in complexes I and II relative
to the chelate ring planes are schematically shown in
Fig. 5.
The Cl atoms of the pꢀchlorophenyl substituent in
complex III are out the near coordination sphere and
seem to produce no steric effect on the conformation
of the complex.
Since the atoms of the butyl substituents in the forꢀ
Therefore, the position of the Cl atom in the chloꢀ mazan molecules of complex II are disordered, lowꢀ
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 36
No. 3
2010

218
PERVOVA et al.
C(3)
C(2)
C(4)
C(1)
C(5)
Cl(2)
C(6)
N(1)
S(1)
C(32)
C(33)
C(30)
C(27)
C(7)
C(26)
N(9)
C(29)
N(7)
C(25)
C(24)
C(19)
C(31)
C(34)
C(28)
N(6)
N(10)
N(2)
N(3)
S(2)
Fe(1)
C(20)
C(36)
C(23)
C(35)
C(21)
C(22)
C(8)
N(5)
C(18)
C(13)
C(9)
N(4)
C(12)
C(17)
C(14)
C(16)
Cl(1)
C(15)
C(10)
C(11)
Fig. 3. Structure II
.
C(30)
C(29)
C(2)
C(3)
C(4)
C(33)
C(32)
Cl(2)
C(27)
C(26)
C(5)
N(9)
C(1)
C(31)
C(36)
C(34)
C(35)
C(6)
C(28)
N(10)
N(8)
S(1)
N(1)
Fe(1)
N(7)
C(7)
C(25)
N(6)
C(18)
C(13)
N(2)
C(17)
N(3)
N(5)
N(4)
S(2)
C(16)
C(15)
C(24)
C(19)
C(10)
C(8)
C(23)
C(12)
C(21)
C(9)
Cl(1)
C(14)
C(20)
C(11)
C(22)
Fig. 4. Structure III
.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 36
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2010

NICKEL(II) AND IRON(II) COMPLEXES
219
Cl
H
H
Cl
H
Cl
H
Fe
Ni
Cl
(I)
(II)
Fig. 5. Schematic orientations of the oꢀchlorophenyl substituents relative to the chelate ring planes in complexes I and II.
[
Russ. J. Inorg. Chem. (Engl. Transl.), vol. 54, no. 3,
temperature experiments were required (120(2) K,
Table 1).
p. 396].
2. Vishnevskaya, G.P., Frolova, E.N., Pervova, I.G., et al.,
Koord. Khim., 2005, vol. 31, no. 11, p. 873 [Russ. J.
Coord. Chem. (Engl. Transl.), vol. 31, no. 11, p. 828].
3. Rezinskikh, Z.G., Slepukhin, P.A., Lipunova, G.N.,
et al., Koord. Khim., 2008, vol. 34, no. 9, p. 663 [Russ.
J. Coord. Chem. (Engl. Transl.), vol. 34, no. 9, p. 653].
The molecular packing of the complexes is characꢀ
terized by a rather loose stacking of complexes
I and
III along the axis . In complex II, the packing is comꢀ
x
plicated by the presence of two independent moleꢀ
cules.
To sum up, in reactions with nickel and iron salts,
1ꢀ(2ꢀchlorophenyl)benzothiazolylformazans function
as tridentate ligands to form metal complexes of the
4. Gilroy, J.B., Patrick, B.O., McDonald, R., and
Hicks, R.G., Inorg. Chem., 2008, vol. 47, no. 4, p. 1287.
5. Szymczyk, M., ElꢀShafei, A., and Freeman, H.S., Dyes
and Pigments, 2007, vol. 72, p. 8.
'
general formulas ML2, and ML2 with the coordinaꢀ
tion polyhedron MN6. We understood how the comꢀ
plexing metal influences the structure of the coordinaꢀ
tion polyhedron in the Ni(II) and Fe(II) complexes
with formazans obtained.
6. Abakumov, G.A., Cherkasov, V.K., Bubnov, M.P., et al.,
Izv. Akad. Nauk, Ser. Khim., 2006, no. 1, p. 43.
7. Shvedenkov, Yu.G., Virovets, A.V., and Lavrenoꢀ
va, L.G., Izv. Akad. Nauk, Ser. Khim., 2003, no. 6,
p. 1281.
8. Uraev, A.I., Ikorskii, V.N., Bubnov, M.P., et al., Koord.
Khim., 2006, vol. 32, no. 4, p. 299 [Russ. J. Coord.
Chem. (Engl. Transl.), vol. 32, no. 4, p. 287].
ACKNOWLEDGMENTS
This work was supported by the Russian Foundaꢀ
tion for Basic Research, project nos. 07ꢀ03ꢀ12050ofi
and 08ꢀ03ꢀ13512ofi_ts.
9. Shmelev, L.V., Lipunova, G.N., Kessenikh, A.V., et al.,
Koord. Khim., 1993, vol. 19, no. 3, p. 215.
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