Download Syntheses and X-ray crystallographic studies of {[Ni(en)2(pot)2]0.5

Polyhedron 28 (2009) 461–466
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Polyhedron
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Syntheses and X-ray crystallographic studies of {[Ni(en)2(pot)2]0.5CHCl3}
and [Ni(en)2](3-pytol)2
M. Singh a, A.K. Pandey c, R.J. Butcher b, N.K. Singh a,*
a
Department of Chemistry, Banaras Hindu University, Varanasi 221005, India
Department of Chemistry, Howard University, 525 College Street NW, Washington, DC 20059, USA
c
UP (PG) College, Varanasi 221002, India
b
a r t i c l e
i n f o
Article history:
Received 19 August 2008
Accepted 18 November 2008
Available online 20 January 2009
Keywords:
Ni(II) 1,3,4-oxadiazole complexes
Mixed-ligand complexes
en complexes
a b s t r a c t
Two novel Ni(II) complexes {[Ni(en)2(pot)2]0.5CHCl3} (3) {pot = 5-phenyl-1,3,4-oxadiazole-2-thione} (1)
and [Ni(en)2](3-pytol)2 (4) {3-pytol = 5-(3-pyridyl)-1,3,4-oxadiazole-2-thiol} (2) have been synthesized
using en as coligand. The metal complexes have been characterized by physical and analytical techniques
and also by single crystal X-ray studies. The complexes 3 and 4 crystallize in monoclinic system with
space group P21/a and P121/c, respectively. The complex 3 has a slightly distorted octahedral geometry
with trans (pot) ligands while 4 has a square planar geometry around the centrosymmetric Ni(II) center
with ionically linked trans (3-pytol) ligands. The p p (face to face) interaction plays an important role
along with hydrogen bondings to form supramolecular architecture in both complexes.
Ó 2008 Elsevier Ltd. All rights reserved.
1. Introduction
The transition metal complexes of dithiocarbazates have attracted considerable attention for their interesting biological applications [1–3]. They behave as versatile ligands and act as
monodentate (S or N2), bidentate anionic (via N3–S or S,S) [4–6]
and polydentate chelating ligands [7–11]. The conversion of potassium salt of N-aroyldithocarbazates and 3-acyldithiocarbazic acid
esters to the corresponding 1,3,4-oxadiazoles are reported in the
literature [12–16]. A few papers are available on the metal complexes of 5-phenyl-1,3,4-oxadiazole-2-thiol/thione [17–19], 5-(4pyridyl)-1,3,4-oxadiazole-2-thione [20–25] and 5-(2-pyridyl)1,3,4-oxadiazole-2-thione [26]. These oxadiazoles have attracted
attention in the field of coordination chemistry because of the
presence of potential multifunctional donor sites viz. exocyclic sulfur, endocyclic nitrogen and pyridyl nitrogen. The pyridyl containing oxadiazoles are known to show three types of binding modes
involving monodentate (Noxa/Npy/S)/bidentate (Npy,Noxa/Npy,S)/tridentate (Npy, Noxa, S) donor sites [21]. Recently, we have reported
the X-ray structure of [Ni(en)2(3-pyt)2] {3-pyt = 5-(3-pyridyl)1,3,4-oxadiazole)-2-thione} where the ligand is covalently bonded
through the endocyclic nitrogen [27]. Following our interest in the
study of the metal complexes of 1,3,4-oxadiazoles-2-thione/thiol,
we report herein the syntheses, spectroscopic and X-ray structural
* Corresponding author. Tel.: +91 542 6702452; fax: +91 542 2368127.
E-mail addresses: [email protected] (M. Singh), singhnk_bhu@yahoo.
com (N.K. Singh).
0277-5387/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2008.11.046
studies of two new Ni(II) complexes viz. {[Ni(en)2(pot)2]0.5CHCl3}
(3) and [Ni(en)2](3-pytol)2 (4).
2. Experimental
2.1. Materials and methods
All starting materials of analytical grade were obtained commercially and used as received. Nicotinamide was purchased from
Sigma Aldrich Chemicals (USA) and used as such. Nicotinic acid
hydrazide [28], [Ni(en)2(NCS)2] [29], potassium N-benzoyldithiocarbazate (1) [30] and potassium[pyridine-3-carbonyl)]-hydrazinecarbodithioate (2) [21] were synthesized according to the reported
methods.
2.2. Synthesis of {[Ni(en)2(pot)2]0.5CHCl3} (3)
A methanol–water (9:1 v/v) solution (20 ml) of [Ni(en)2(NCS)2]
(1 mmol) was mixed with the aqueous-methanolic solution
(50:50 v/v) (10 ml) of potassium N-benzoyldithiocarbazate (1)
(2 mmol) to which 2 ml of chloroform was added. The resulting
solution was filtered off and kept for crystallization. After 12 days,
light pink crystals of 3 suitable for an X-ray crystallographic study
were obtained.
{[Ni(en)2(pot)2]0.5CHCl3} (3): Pink crystals, Yield 67%, Anal. calc.
(%) for C41H53Cl3N16Ni2O4S4 (1186.00): C, 41.52; H, 4.50; N, 18.90;
S, 10.81; Ni, 9.90. Found: C, 40.96; H, 4.30; N, 18.77; S, 10.75; Ni,
9.27%. lB = 2.90 BM per Ni(II). M.p. 200 °C (dec.). IR data (m, KBr,
cm1): m(NH of en) 3255m; m(C@N) 1604s; ms(C–O–C) 1276w;
462
M. Singh et al. / Polyhedron 28 (2009) 461–466
mas(C–O–C) 1182; m(N–N) 1059s; m(C@S) 948m; m(Ni–N) 470. UV–
Vis spectrum [kmax in MeOH, cm1]: 15001, 22345, 32038.
2.3. Synthesis of [Ni(en)2](3-pytol)2 (4)
A methanol solution (10 ml) of Ni(OAc)2 2H2O (1 mmol) was
stirred with the aqueous-methanolic solution (50:50 v/v) (10 ml)
of potassium[N0 -(pyridine-3-carbonyl)-hydrazinecarbodithioate]
(1) (2 mmol), the precipitated green product was filtered off and
washed twice with cold water. The above precipitate was added
to a MeOH solution of en and shaken for a few minutes, the resulting solution of 4 was filtered off and kept for crystallization and
after 25 days, red-pink crystals of 4 suitable for an X-ray crystallography study were obtained.
[Ni(en)2](3-pytol)2 (2): Red pink, Yield 58%, Anal. Calc. for
C18H24N10O2S2Ni (535.30) C, 40.39; H, 4.52; N, 26.17; S; 11.98;
Ni, 10.96. Found: C, 39.98; H, 4.86; N, 26.66; S, 11.52; Ni, 10.62%.
lB = 0, Diamagnetic. M.p. 225 °C (dec.). IR data (m, KBr, cm1);
m(NH of en) 3229m; m(C@N) 1610s; ms(C–O–C) 1275; mas(C–O–C)
1198w ; m(N–N) 1087s; m(C–S) 904m; m(Ni–N) 476; Pyridine ring
699. UV–Vis [kmax, MeOH, cm1]: 16500, 20350, 31645.
3. Analyses and physical measurements
Carbon, hydrogen, nitrogen and sulfur contents were estimated
on a CHN Model CE-440 Analyser and on an Elementar Vario EL III.
Magnetic susceptibility measurements were performed at room
temperature on a Cahn Faraday balance using Hg[Co(NCS)4] as
the calibrant and the electronic spectra were recorded on an UV1700 Pharmaspec spectrophotometer. By following standard procedure, the complexes were analyzed for their nickel content, after
decomposition with a mixture of conc. HNO3 and HCl, followed by
conc. H2SO4 [31]. I.R. spectra were recorded in the 4000–400 cm1
region as KBr pellets on a Varian 3100 FT-IR Excalibur series.
4. Crystal structure determination
Data for the complex 3 was obtained at 173(2) K on a Bruker
three-circle diffractometer equipped with a SMART 6000 CCD diffractometer and for 4, X-ray single crystal refinement, diffraction
data collection and data reduction were performed at
200(2) K
0
A) radiation
with a graphite monochromated Mo Ka (k = 0.71073 Å
source using standard methods [32]. Intensity measurements were
performed on a rapidly cooled crystal. The structure was solved by
direct methods (SHELX-97) and refined against all data by full-matrix least-squares on F2 using anisotropic displacement parameters
for all non-hydrogen atoms. All hydrogen atoms were included in
the refinement at geometrically ideal positions and refined with
a riding model [33,34]. MERCURY was used for molecular graphics
[35]. Crystal structure diagrams were generated by use of the ORTEP-3 for Windows program [36]. The crystallographic data and
structural refinement details of complex 3 and 4 are given in Table
1 whereas the important bond distances and bond angles of complex 3 and 4 are given in Tables 2 and 4. The details of hydrogen
bonds are given in Tables 4 and 5.
5. Results and discussion
As a part of our study on metal complexes of 1,3,4-oxadiazole2-thione/thiol [17,27], we report herein the preparation, spectroscopic and X-ray studies of two new Ni(II) complexes based on
5-phenyl-1,3,4-oxadiazole-2-thione (pot) and 5-(3-pyridyl)1,3,4-oxadiazole-2-thiol (3-pytol). The potassium salt of
N-acyldithiocarbazates lead to ring closure by desulphurization
into the corresponding 1,3,4-oxadiazole during complexation
Table 1
Crystal refinement parameters of complexes 3 and 4.
Parameters
3
4
Empirical formula
Formula weight
Space group
Crystal system
T (K)
k, Mo Ka
a (Å)
b (Å)
c (Å)
a (°)
b (°)
c (°)
V (Å3)
Z
qcalcd (Mg/m3)
l (mm1)
F(0 0 0)
Crystal size (mm3)
H range for data collection
Index ranges
C41H53Cl3N16Ni2O4S4
1186.00
P21/a
Monoclinic
173(2) K
0.71073
12.4655(18)
20.993(3)
21.540(3)
90
90.0010(10)
90
5636.6(14)
4
1.398
1.011
2456
0.50 0.25 0.18
0.95–29.59
17 6 h 6 12
28 6 k 6 28
29 6 l 6 29
60 761
15 565
15 565/14/682
0.988
0.0665, 0.2213
0.1258, 0.2825
1.631, 0.690
C18H24N10O2S2Ni
535.30
P121/c1
Monoclinic
200(2)
0.71073
6.8070(4)
25.4347(14)
7.1890(5)
90
114.213(7)
90
1135.17(12)
2
1.566
1.078
556
0.47 0.34 0.12
4.59–34.85
10 6 h 6 10
40 6 k 6 36
8 6 l 6 11
11 926
4608
4608/0/151
0.925
0.0413, 0.0761
0.0831, 0.0836
0.606, 0.392
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness-of-fit on F2
R1a, wR2b [I > 2r(I)]
R1a, wR2b (all data)
Largest difference peak and hole
(e Å3)
Table 2
Selected bond lengths and bond angles for complex 3.
Bond lengths (Å)
Ni(1)–N(1A)
Ni(1)–N(3A)
Ni(1)–N(2A)
Ni(3)–N(2C)
Ni(3)–N(5C)
Ni(3)–N(1C)
2.113(4)
2.117(5)
2.125(4)
2.097(4)
2.109(4)
2.111(3)
Ni(2)–N(2B)
Ni(2)–N(1B)
Ni(2)–N(3B)
Ni(3)–N(3C)
Ni(3)–N(7C)
Ni(3)–N(4C)
2.118(4)
2.120(4)
2.121(5)
2.104(4)
2.110(4)
2.115(3)
Bond angles (°)
N(1A)#1–Ni(1)–N(3A)
N(1A)–Ni(1)–N(3A)
N(3A)#1–Ni(1)–N(3A)
N(1A)–Ni(1)–N(2A)
N(3A)–Ni(1)–N(2A)
N(2B)–Ni(2)–N(1B)
N(2B)#2–Ni(2)–N(3B)
N(1B)#2–Ni(2)–N(3B)
N(5C)–Ni(3)–N(1C)
N(3C)–Ni(3)–N(4C)
N(1C)–Ni(3)–N(4C)
90.81(18)
89.19(18)
180.00(19)
82.27(15)
89.21(17)
82.02(15)
90.90(17)
90.77(18)
91.50(16)
82.64(15)
179.72(13)
N(1B)–Ni(2)–N(3B)
N(3B)#2–Ni(2)–N(3B)
N(2C)–Ni(3)–N(3C)
N(3C)–Ni(3)–N(5C)
N(2C)–Ni(3)–N(7C)
N(5C)–Ni(3)–N(7C)
N(2C)–Ni(3)–N(1C)
N(3C)–Ni(3)–N(1C)
N(7C)–Ni(3)–N(1C)
N(5C)–Ni(3)–N(4C)
89.23(18)
180.00(19)
179.29(12)
90.92(16)
89.90(16)
179.63(12)
82.83(15)
97.31(15)
88.30(15)
88.78(16)
[17,27]. Recently, the crystal structure of [Ni(en)2(3-pyt)2] based
on 5-(3-pyridyl)-1,3,4-oxdiazole-2-thione has been reported [27].
The present work reports the complex [Ni(en)2](3-pytol)2 of the
same ligand in the thiol form. The 5-(3-pyridyl)-1,3,4-oxdiazole2-thiol can exist in two forms viz. [H(3-pytone)] (thione) and
[H(3-pytol)] (thiol). These two forms of the ligand yielded octahedral and square planar complexes, respectively, with Ni(II). It is observed that the reaction of an aqueous-methanol solution of
[K+(H2L)] and methanol solution of Ni(OAc)2 4H2O formed a
green precipitate which dissolved in the methanol solution of en
(ethylenediamine) resulting in a red-pink solution which crystallized to give red-pink crystals of [Ni(en)2](3-pytol)2. However,
the reaction of methanol–water solution of [K+(H2L)] and methanol solution of [Ni(en)2(NCS)2] gave a reddish solution which crystallized to form dark red crystals of [Ni(en)2(3-pyt)2].
M. Singh et al. / Polyhedron 28 (2009) 461–466
Table 3
Hydrogen bonds for complex 3 [Å and °].
D–H A
d(D–H)
d(H A)
d(D A)
<(DHA)
N(1A)–H(1AC) S(1A)
N(1A)–H(1AD) N(4A)#1
N(2A)–H(2AC) S(1A)1#
N(2A)–H(2AD) N(4A)
N(1B)–H(1BC) N(4B)#2
N(1B)–H(1BD) S(1B)
N(2B)–H(2BC) N(4B)
N(2B)–H(2BD) S(1B)#2
N(1C)–H(1CC) S(1C)
N(1C)–H(1CD) N(8C)
N(2C)–H(2CC) S(2C)
N(2C)–H(2CD) N(6C)
N(3C)–H(3CC) N(8C)
N(3C)–H(3CD) S(1C)
N(4C)–H(4CC) N(6C)
N(4C)–H(4CD) S(2C)
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
0.92
2.70
2.65
2.71
2.63
2.68
2.71
2.63
2.70
2.75
2.59
2.69
2.57
2.57
2.67
2.65
2.72
3.475(5)
3.226(6)
3.487(5)
3.216(6)
3.252(7)
3.476(5)
3.226(6)
3.477(5)
3.505(4)
3.174(6)
3.474(5)
3.161(6)
3.160(6)
3.453(5)
3.225(6)
3.477(5)
141.9
121.6
142.8
122.4
121.4
141.3
123.0
143.1
140.4
121.8
143.3
122.8
122.3
143.4
120.9
140.6
Symmetry transformations used to generate equivalent atoms: #1 x + 1,y + 1,
z + 1 #2 x + 1,y + 1,z.
Table 4
Selected bond lengths and bond angles for complex 4.
Ni coordination sphere
Ni–N(11)
2.0235(12)
Ni–N(11)#1
2.0235(12)
Ni–N(12)
2.0138(13)
Ni–N(12)#1
2.0138(13)
N(12)–Ni–N(11)#1
N(12)#1–Ni–N(11)#1
N(12)#1–Ni–N(11)
N(11)–Ni–N(11)#1
N(12)–Ni–N(11)
N(12)#1–Ni–N(12)
95.17(5)
84.83(5)
95.17(5)
180.0
84.83(5)
180.00(5)
Ionic distances
Ni–S#1
Ni–S
2.997
2.997
S#1–Ni–S
180.00
Ethylenediamine
N(11)–C(11)
N(12)–C(12)
C(11)–C(12)
1.483(2)
1.482(2)
1.512(2)
C(11)–N(11)–Ni
C(12)–N(12)–Ni
N(11)–C(11)–C(12)
N(12)–C(12)–C(11)
108.23(9)
107.77(9)
107.37(12)
107.30(13)
Oxadiazole ring
S–C(1)
O–C(2)
O–C(1)
N(1)–C(1)
N(1)–N(2)
N(2)–C(2)
N(2)–C(2)–O
O–C(2)–C(3)
1.6915(16)
1.3634(18)
1.3916(18)
1.313(2)
1.4047(19)
1.290(2)
112.29(13)
120.02(13)
C(2)–O–C(1)
C(1)–N(1)–N(2)
C(2)–N(2)–N(1)
N(1)–C(1)–O
N(1)–C(1)–S
O–C(1)–S
N(2)–C(2)–C(3)
103.81(11)
107.39(13)
106.72(13)
109.79(13)
129.78(13)
120.43(11)
127.65(14)
Table 5
Hydrogen bonds for complex 4 [Å and °].
D–H A
d(D–H)
d(H A)
d(D A)
<(DHA)
N(11)–H(11C) N(1)#1
N(11)–H(11D) N(1)#2
N(12)–H(12C) N(2)
N(12)–H(12D) S#3
0.92
0.92
0.92
0.92
2.32
2.14
2.13
2.86
3.1360(18)
3.0302(19)
3.0456(18)
3.6479(14)
147.8
162.3
172.4
144.1
Symmetry transformations used to generate
x + 1,y + 1,z + 1 #2 x 1,y,z #3 x 1,y,z 1
equivalent
atoms:
#1
The possible pathways followed for the formation of two types
of complexes are shown in scheme 1. The ligand [K+(H2L)] reacts
with Ni(OAc)2 4H2O to give a green precipitate (Scheme 1) in
which Ni(II) is bonded through both thiolato sulfur in a square planar form. It is believed that this green product on reaction with a
strong chelating ligand en replaced (H2L) and formed [Ni(en)2]2+,
maintaining the earlier square planar geometry. During this process (H2L) got cyclized into 5-(3-pyridyl)-1,3,4-oxadizole-2-thiol
463
in the presence of en. The positive charge of the complex cation
[Ni(en)2]2+ is balanced by two thiolato (3-pytol) ligands resulting
in the formation of the complex [Ni(en)2](3-pytol)2.
The route followed for the formation of [Ni(en)2(3-pyt)2] from
[Ni(en)2(NCS)2] and [K+(H2L)] is shown in scheme 1(ii) where
[K+(H2L)] is slowly cyclized to 5-(3-pyridyl)-1,3,4-oxadiazole-2thione in aqueous-methanol which then exchanges N-bonded thiocyanato from [Ni(en)2(NCS)2] and finally yields [Ni(en)2(3-pyt)2]
maintaining the octahedral geometry around Ni(II).
5.1. I.R. spectra
The I.R. spectra of potassium N-benzoyldithiocarbazate [17]
and potassium[N0 -(3-pyridine-carbonyl)hydrazinecarbodithioate
[K+(H2L)] [27] are compared with the I.R. spectra of their
respective Ni(II) complexes which indicate that bands due to
–C(O)NHNHC(S)– moiety i.e. m(C@O), thioamide I, thioamide II
and m(C@S) are absent [37]. In addition, the I.R. spectra of both
complexes are devoid of any peak due to m(NH) which are present
in the ligands 1 and 2. Appearance of new bands at 1604–
1610 cm1 (endocyclic C@N), 1276–1275 [mas(C–O–C)] and 1182–
1198 [ms(C–O–C)] cm1, suggest cyclization of the acyclic dithiocarbazate moiety. The I.R. data are thus consistent with the presence
of 1,3,4-oxadiazole moiety [38]. The absorption in the region of
3255–3229 cm1 is due to NH stretching vibrations of en.
5.2. Electronic spectra and magnetic moments
The magnetic moment of 2.90 B.M. for {[Ni(en)2(pot)2]0.5CHCl3}
and the presence of two d–d bands at 15001 and 22345 cm1 assigned to the 3A2g(F) ? 3T1g(F) and 3T1g(P) transitions, respectively,
suggest an octahedral geometry around Ni(II) in the complex 3 [39].
The diamagnetism of [Ni(en)2](3-pytol)2 and occurrence of two
bands at 16 500 and 20 350 cm1 assigned to the 1A1g ? 1B2g and
1
B1g transitions, respectively suggest it to be square planar. Other
band at 32 035–31 645 cm1 in 3 and 4, respectively, may be due
to charge transfer/intraligand transition [39].
6. Crystal structure description of {[Ni(en)2(pot)2]0.5CHCl3} (3)
As depicted in Fig. 1, the basic building unit consists of one Ni
cation, two (pot) ligands and two neutral ethylenediamine (en)
molecules resulting in a distorted octahedral geometry with NiN6
core. One unit of {[Ni(en)2(pot)2]0.5CHCl3} possesses the centrosymmetric nickel at inversion center. There are interstitial CHCl3
molecules in the structure of 3 (Fig. 1). The two axial (pot) anions
around each Ni(II) at trans positions are bonded through nitrogen
atoms at a distance of Ni1–N(3A), Ni1–N(3A)#1 = 2.117(5) (#1 =
x + 1,y + 1,z + 1) , Ni2–N(3B), Ni2–N(3B)#1 = 2.121(5) (#1 =
x + 1,y + 1,z + 1) and Ni3–N(5C) = 2.109(4), Ni3–N(7C) =
2.110(4) Å, respectively and the four equatorial sites are occupied
by two bidentate N,Ń-ethylenediamine. The bonding of en to Ni(II)
through Ni1–N1A = Ni1–N1A#1 and Ni1–N2A = Ni1–N2A#1 with a
bond distances of 2.113(4) and 2.125(4) Å form two five membered
chelate rings NiN2AC2N1A and NiN2BC2N1B with bite angles of
82.28(13)° and 82.03(13)°, respectively. All N1A, N1A#1, N1B and
N1B#1 atoms of en involved in bonding with Ni1 lie in the same
plane. Similar arrangement of other two units of [Ni2(en)2]2+ and
[Ni3(en)2]2+ core are also observed. The geometry and bonding
parameters within en molecules are in good agreement with those
of related compounds eg [Ni(en)2(3-pyt)2] {(3-pyt) = 5-(3-pyridyl)-1,3,4-oxadiazole-2-thione [27], [Ni{trans-(L)2(en)2]{L = N-(5chlorouracilato) [40], isothiocyanato [41] and salicylato [42]}.
Almost planar (pot) ligands in complex 3 bonded to Ni(II) and
designated as Ni1–N(3A) = Ni1–N(3A)#1 = 2.117(5), Ni2–N(3B) =
464
M. Singh et al. / Polyhedron 28 (2009) 461–466
(i)
O
O
S
NH
NH
C
2
S
(MeOH)
[K+(H2L)-]
N
Ni
C
NH
+ Ni(OAc)2.4H2O
SK
S
NH
2
N
excess en
(MeOH)
(MeOH-H 2O)
N
O
H2 N
N
NH2
Ni
S
N
H2 N
N
S
NH2
Ni
N
O
N
[Ni(en)2](3-pytol)2
(ii)
O
S
NH
NH
Slowly
C
2
SK
N
S
O
2
N
[K+(H2L)-]
N
NH
[H(3-pyt)]
(MeOH-H 2O)
Ni(en)2(NCS)2
(MeOH)
S
H2 N
O
N
N
H2 N
NH2
Ni
N
NH2
N
N
O
S
N
[Ni(en)2(3-pyt)2]
Scheme 1.
Fig. 1. Molecular structure of {[Ni(en)2(pot)2]0.5CHCl3} with heteroatom labeling
scheme. The hydrogen atoms are omitted for clarity.
Ni2–N(3B)#1 = 2.121(5) and Ni3–N(5C) = 2.109(4), Ni3–N(7C) =
2.110(4) Å are almost equal but significantly lengthened in comparison to the corresponding bond lengths of 1.907(3) and
1.895(4) Å reported for [Ni{N5-(2-dimethylaminoethyl)cyclopentadienyl}(pti)]0.5(C7H8) [43], [Ni{N5-(1-methy-lindene)(pti)(PPh3)]
[44], {pti = phthalimidate} respectively, but comparable to those
of ca. 2.1090(14), 2.1150 Å encountered in the related [Ni(en)2(3pyt)2] {(3-pyt) = 5-(3-pyridyl)-1,3,4-oxadiazole-2-thione} [27]
and ca. 2.102 Å for N-succinimido compound [Ni(succinimido(H2O)4] 2H2O [45]. All hydrogens of NH2 groups are involved
in H-bonding to the thione sulfur and oxadiazole nitrogen of
(pot), thus providing intramolecuar hydrogen bonding in all three
units of the complex 3. These hydrogen bondings have stabilized 3
in the solid state (Table 3). The shortest intra and interchain Ni Ni
separations are 12.208 and 8.203 Å, respectively. The intermolecular hydrogen bonding between the thione sulfur of one (pot) anion of one asymmetric unit with the hydrogen atom of the phenyl
Fig. 2. Mercury view of the crystal packing of {[Ni(en)2(pot)2]0.5CHCl3} showing
face to face (p p) interactions between two phenyl rings.
ring (S H = 2.954 Å) extended the chain in one dimension along a
axis. Further two p p interactions between carbon atoms of adjacent phenyl rings have distances of 3.367 (C9A. . .C11C) and 3.385
(C9B. . .C19C) Å while centroid (Cg1)–centroid (Cg2) separation be-
M. Singh et al. / Polyhedron 28 (2009) 461–466
tween two phenyl rings is 4.058 and 4.063 Å which cause the chain
to grow in one dimension (Fig. 2). This one dimensional framework
is extended into two dimensional network due to the presence of
[Ni(en)2]2+ unit perpendicular to trans (pot) ligands. The whole
arrangement provides one dimensional open channel enclosing
the CHCl3 molecules and gives 2D dimensional supramolecular
architecture (Fig. 3). The CHCl3 molecules are stable in the open
channels due to the presence of weak intermolecular interactions
between phenyl ring of (pot) and hydrogen atom of the CHCl3.
Fig. 3. The molecular packing of {[Ni(en)2(pot)2]0.5CHCl3} (3), view along a axis.
The CHCl3 molecules are represented as space filling form.
465
7. Crystal structure of [Ni(en)2](3-pytol)2 (4)
The X-ray crystal structure analysis of 4 shows that [Ni(en)2]2+
cation is surrounded by two (3-pytol) anions. In the centrosymmetric unit of [Ni(en)2](3-pytol)2, the metal ion has a square planar
geometry where Ni(II) is bonded with four symmetry related Natoms of two en molecules and is ionically linked with thiolato sulfur of two (3-pytol) anions. The two en molecules chelate Ni(II) at
equatorial positions and two (3-pyt) occupy apical positions in
trans manner (Fig. 4). The Ni–N distances in complex 4 are in the
range of 2.0138(13)–2.0235(12) Å which is almost normal for Ni–
N (amine) bonds [21,30]. The bite angle for NiN4 core is 84.83(5)
indicating a substantial distortion in the molecule with two five
membered NiC2N2 chelate rings around Ni(II). In the [Ni(en)2]2+
,
the nickel(II) and the donor atoms of ethylenediamine lie in the
same plane. Each [Ni(en)2]2+ forms a pair of weak intermolecular
Ni S interactions at a distance of 2.997 Å. The Ni(II) present in a
D2h symmetry is bonded to four N atoms of NH2 group of en which
offer interesting hydrogen bonding packing. The elements of the
structure are joined to each other in the crystal packing by means
of extended system of hydrogen bonding. The p p interaction is
observed between two adjacent pyridine rings as shown in Fig. 5.
Fig. 4. Molecular structure of {[Ni(en)2](3-pytol)2 (4) with heteroatom labeling
scheme.
Fig. 5. Mercury view of the crystal packing of [Ni(en)2](3-pytol)2 showing face to face (p p) interaction, weak Ni S and weak C S interactions along with hydrogen
bonding.
466
M. Singh et al. / Polyhedron 28 (2009) 461–466
The centroid (Cgpyridine) to centroid (Cgpyridine) separation is of
3.653 Å. The hydrogen bonding parameters are listed in Table 5.
The X-ray analysis reveals that in the solid state the molecules are
self assembled via. N–H N, N–H O and N–H S intermolecular
hydrogen bonding and weak C S interactions (4.274 Å) between
the thioalto sulfur and carbon of phenyl ring. This hydrogen bonding
together with p p interaction form metal organic framework of
three dimensional network (Fig. 5).
8. Conclusion
Two new complexes [Ni(en)2(pot)2]0.5CHCl3 and [Ni(en)2](3pytol)2 containing en and 1,3,4-oxadiazole have been synthesized
and fully characterized by X-ray techniques. The desulphurization
of the N-acylhydrazinecarbodithioate {–C(O)–NHNH–C(S)–} moiety was observed during complexation. The [Ni(en)2](3-pytol)2 is
a rare example of Ni(II) complex containing two en molecules in
a square planar geometry.
Acknowledgments
One of the authors (Mamata Singh) is thankful to CSIR, New
Delhi, India for the award of SRF in a Project supported by Grant
Nos. 01(2152)07/EMR-II and 9/13(160)/2008EMR-I.
Appendix A. Supplementary data
CCDC 656471 and 693644 contain the supplementary crystallographic data for 3 and 4. These data can be obtained free of charge
via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the
Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: [email protected]. Supplementary data associated with this
article can be found, in the online version, at doi:10.1016/
j.poly.2008.11.046.
References
[1] M.A. Ali, S.E. Livingston, Coord. Chem. Rev. 13 (1974) 101.
[2] J.P. Scovill, D.L. Klayman, C. Lambros, G.E. Childs, J.D. Notsch, J. Med. Chem. 27
(1984) 87.
[3] J.P. Scovill, D.L. Klayman, C.F. Franchino, J. Med. Chem. 25 (1982) 1261.
[4] M. Das, S.E. Livingston, Inorg. Chim. Acta 19 (1976) 5.
[5] A. Marchi, L. Uccelli, L. Marvelli, R. Rossi, M. Giganti, V. Bertolasi, V. Ferretti, J.
Chem. Soc., Dalton Trans. (1996) 3105.
[6] A.I. El-Said, Trans. Met. Chem. 28 (2003) 749.
[7] M.A. Ali, A.H. Mirza, M.H.S.A. Hamid, F.H. Bujang, P.V. Bernhardt, Polyhedron
23 (2004) 2405.
[8] N.R. Pramanik, S. Ghosh, T.K. Raychaudhuri, S. Ray, R.J. Butcher, S.S. Mandal,
Polyhedron 23 (2004) 1595.
[9] M.A. Ali, A.H. Mirza, M. Nazimuddin, R. Ahmed, L.H. Gahan, P.V. Bernhardt,
Polyhedron 22 (2003) 1471.
[10] M.A. Ali, A.H. Mirza, A.L. Tan, L.K. Wei, P.V. Bernhardt, Polyhedron 23 (2004)
2037.
[11] S. Gou, X. You, Z. Zu, Z. Zhou, K. Yu, Polyhedron 10 (1991) 1363.
[12] A. Hetzheim, K. Möckel, Adv. Heterocycl. Chem. 7 (1966) 183.
[13] B.L. Sharma, S.K. Tandon, Pharmazie 39 (H-12) (1984) 858.
[14] J.R. Reid, N.D. Heindel, J. Heterocycl. Chem. 13 (1976) 925.
[15] H. Foks, J. Mieczkowska, M. Janowiec, Z. Zwolska, Z. Andrzejczyk Chem.
Heterocycl. Comp. 38 (2002) 810.
[16] E. Hoggarth, J. Chem. Soc. (1952) 4811.
[17] P. Tripathi, A. Pal, V. Jancik, A.K. Pandey, J. Singh, N.K. Singh, Polyhedron 26
(2007) 2597.
[18] O.H. Amin, L.J. Al-Hayaly, S.A. Al-Jibori, T.A.K. Al-Allaf, Polyhedron 23 (2004)
2013.
[19] C.-L. Ma, G.-R. Tian, R.-F. Zhang, Polyhedron 24 (2005) 1773.
[20] Z.-H. Zhang, Y.-L. Tian, Y.-M. Guo, Inorg. Chim. Acta 360 (2007) 2783.
[21] M. Du, Z.-H. Zhang, X.-J. Zhao, Q. Xu, Inorg. Chem. 45 (2006) 5785.
[22] Z.-H. Zhang, C.-P. Li, Y.-L. Tian, Y.-M. Guo, Inorg. Chem. Commun. 11 (2008)
326.
[23] Y.-T. Wang, G.-M. Tang, W.-Y. Ma, W.-Z. Wan, Polyhedron 26 (2007) 782.
[24] Y.-T. Wang, G.-M. Tang, J. Coord. Chem. 60 (2007) 2139.
[25] Y.-T. Wang, G.-M. Tang, Inorg. Chem. Commun. 10 (2007) 3.
[26] Y.-T. Wang, G.-M. Tang, Z.-W. Qiang, Polyhedron 26 (2007) 4542.
[27] M. Singh, R.J. Butcher, N.K. Singh, Polyhedron 27 (2008) 3151.
[28] T. Curtius, J. Prakt. Chem. 50 (1894) 278.
[29] B.W. Brown, E.C. Lingafelter, Acta Crystallogr. 16 (1963) 753.
[30] M. Busch, M. Starke, J. Prakt. Chem. 93 (1916) 49.
[31] A.I. Vogel, A Text Book of Quantitative Inorganic Analysis, 3rd ed., ELBS,
Longman, London, 1969.
[32] Oxford Diffraction (2007). CrysAlis RED and CrysAlis CCD Versions 1.171.31.8.
Oxford Diffraction Ltd. Abingdon, Oxafordshire, England.
[33] G.M. Sheldrick, Acta Crystallogr., Sect. A 46 (1990) 467.
[34] G.M. Sheldrick, SHELXL-97, Program for Crystal Structure Refinement, University
of Göttingen, Germany, 1997.
[35] I.J. Bruno, J.C. Cole, P.R. Edgington, M. Kessler, C.F. Macrae, P. McCabe, J.
Pearson, R. Taylor, Acta Crystallogr. Sect. B 58 (2002) 389.
[36] L.J. Farrugia, J. Appl. Cryst. 30 (1997) 565.
[37] N.K. Singh, M. Singh, A.K. Pandey, M.K. Bharty, R.J. Butcher, Acta Crystallogr.
Sect. E 63 (2007) 04327.
[38] P. Gómez-Saiz, J. Garcia-Tojal, M.A. Maestro, F.J. Arnaiz, A. Francisco, T. Roja,
Inorg. Chem. 41 (2002) 1345.
[39] A.B.P. Lever, Inorganic Electronic Spectroscopy, 2nd ed., Elsevier, Amsterdam,
1984.
[40] A. Terrón, A. Garcia-Raso, J.J. Fiol, S. Amenqual, M. Barceló-Oliver, R.M. Tótaro,
M.C. Apella, E. Molins, I. Mata, J. Inorg. Biochem. 98 (2004) 632.
[41] P.J. Squattrito, T. Iwamoto, S.-I. Nishikiori, Chem. Commun. (1996) 2665.
[42] H. Icbudak, H. Olmez, O.Z. Yesilel, F. Arslan, P. Naumov, G. Jovanovski, A.R.
Ibrahim, A. Usman, H.-K. Fun, S. Chantrapromma, S.W. Nq, J. Mol. Struct. 657
(2003) 255.
[43] O. Segnitz, M. Winter, R.A. Fischer, J. Organomet. Chem. 691 (2006) 4733.
[44] I. Dubuc, M.-A. Dubois, F. Bélanger-Gariépy, D. Zargarian, Organometallics 18
(1999) 30.
[45] H.J. Cumming, D. Hall, Acta Crystallogr. Sect. B 32 (1976) 1281.