Nickel(II)?π interaction in [M(ampy)2Ni(μ-CN)2(CN)2]n (M = Zn(II) and Cd(II), ampy = 2-aminomethylpyridine): Syntheses, vibrational spectroscopy, thermal analyses and crystal structures of cyano-bridged heteronu

Article abstract of DOI:10.1016/j.molstruc.2008.10.061

Two novel three-dimensional cyano-bridged heteronuclear polymeric complexes, [Zn(ampy)₂Ni(μ-CN)₂(CN)₂]_n (1) and [Cd(ampy)₂Ni(μ-CN)₂(CN)₂]_n (2), (ampy = 2-aminomethylpy

Full text of DOI:10.1016/j.molstruc.2008.10.061

Journal of Molecular Structure 920 (2009) 220–226
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Nickel(II)ꢀ ꢀ ꢀ
p interaction in [M(ampy)2Ni(l-CN)2(CN)2]n (M = Zn(II) and Cd(II),
ampy = 2-aminomethylpyridine): Syntheses, vibrational spectroscopy,
thermal analyses and crystal structures of cyano-bridged heteronuclear
polymeric complexes
b
a
c
Güneßs Süheyla Kürkçüog˘lu a, , Okan Zafer Yeßsilel , Ilkan Kavlak , Orhan Büyükgüngör
_
*
a Eskißsehir Osmangazi University, Faculty of Arts and Sciences, Department of Physics, TR-26480 Eskißsehir, Turkey
b Eskißsehir Osmangazi University, Faculty of Arts and Sciences, Department of Chemistry, TR-26480 Eskißsehir, Turkey
c Ondokuz Mayıs University, Faculty of Arts and Sciences, Department of Physics, TR-55139 Samsun, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Two novel three-dimensional cyano-bridged heteronuclear polymeric complexes, [Zn(ampy)2Ni(
l-
Received 4 September 2008
Received in revised form 27 October 2008
Accepted 30 October 2008
CN)2(CN)2]n (1) and [Cd(ampy)2Ni( -CN)2(CN)2]n (2), (ampy = 2-aminomethylpyridine or 2-picolylamine,
l
C6H8N2) were synthesized and characterized by FT-IR spectroscopy, thermal analyses (TG, DTG and DTA),
elemental analyses and single crystal X-ray diffraction techniques. Vibration assignments were given for
all the observed bands and the spectral feature also supported to the structure of polymeric complexes.
The Ni(II) ion is four coordinate with four cyanide–carbon atoms in a square planar geometry and the
Zn(II) or Cd(II) ion exhibits a distorted octahedral coordination by two bidentate ampy ligands and
two bridging cyano groups as a cis position. In additional, there are also interaction between Ni(II) ion
Available online 13 November 2008
Keywords:
Nickel(II)ꢀ ꢀ ꢀ
p interaction
Cyano-bridged complexes
and the aromatic p-system. The structures of 1 and 2 are similar and consist of 1-D zigzag chains which
Tetracyanonickelate(II) complexes
2-Aminomethylpyridine complexes
Heteronuclear complexes
are linked via intermolecular hydrogen bonding, C–Hꢀ ꢀ ꢀ
p
and Ni(II)ꢀ ꢀ ꢀ
p interactions to give rise to 3-D
networks.
Ó 2008 Elsevier B.V. All rights reserved.
1. Introduction
low-dimensional structures for magnetic applications attract the
interest of chemists and physicists [5–7].
One-, two- and three-dimensional CN-bridged metal complex
In previous studies, several 2-aminomethylpyridine complexes
have been reported [8–17]; however to our knowledge, no tetracy-
anonickelate(II) complex with a 2-aminomethylpyridine ligand as
blocking ligand has been reported. Zinc(II) and cadmium(II) ions,
as the cationic central atom in cyano complexes, generally adopt
a coordination number of six. Non-covalent interactions are very
important in biological structure, supramolecular chemistry and
molecular recognition. The experimental study on complexes have
structures made up of building blocks such as linear ½AgðCNÞ2ꢁꢂ,
2ꢂ
square planar ½NiðCNÞ4ꢁ or tetrahedral ½CdðCNÞ4ꢁ2ꢂ, and of the
complementary ligands such as ammonia, water, unidentate
amine, bidentate
a,x-diaminoalkane, etc., are reviewed with an
emphasis on their behaviour as hosts to afford clathrates inclusion
compounds with guest molecules and as self-assemblies to form
supramolecular structures with or without guests [1]. In particular,
Hofmann-type host structures (ML2Ni(CN)4), which were first pre-
pared by Hofmann and Küspert [2] in 1897 and extensively studied
by Iwamoto [1], show two dimensional structures with a wide
variety of small molecules intercalated between the layers. Such
a multidimensional structure involving cyanometallate anions
and second coordination centres, but without a secondary or com-
plementary ligand like HN3 in the Hofmann-type, was proposed by
Keggin and Miles in 1936 for the three-dimensional structures of
Prussian blue and related complexes based on powder X-ray dif-
fraction data [3,4]. Tetracyanonickelallates exhibiting especially
revealed the great importance of the non-covalent Ni(II)ꢀ ꢀ ꢀ
p bind-
ing force between the Ni(II) ion and the pyridine ring of 2-amino-
methylpyridine ligand. Although cyano-bridged complexes have
been studied extensively, both structurally and spectroscopically
for many years [11,16], these type complexes containing Niꢀ ꢀ ꢀ
p
interaction have not been reported. The nickel(II)ꢀ ꢀ ꢀ
p
interaction
are probably weak, however, they are very import in stabilizing
the polymeric structure of the complexes. In this study, we have
synthesized the two novel three-dimensional cyano-bridged heter-
onuclear polymeric complexes, [Zn(ampy)2Ni(l-CN)2(CN)2]n (1)
and [Cd(ampy)2Ni( -CN)2(CN)2]n (2) and characterized by FT-IR
l
spectroscopy, thermal analyses, elemental analyses and single
* Corresponding author. Tel.: +90 222 2393750; fax: +90 222 2393578.
E-mail address: gkurkcuo@ogu.edu.tr (G.S. Kürkçüog˘lu).
crystal X-ray diffraction techniques.
0022-2860/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2008.10.061

G.S. Kürkçüog˘lu et al. / Journal of Molecular Structure 920 (2009) 220–226
221
Fig. 1. The FT-IR spectra of ampy (a), complex 1 (b) and complex 2 (c) in Nujol.
in Nujol between KBr windows. Perkin–Elmer Diamond TG/DTA
thermal analyzer was used to record simultaneous TG, DTG and
DTA curves in the static air atmosphere at a heating rate of
10 K minꢂ1 in the temperature range 50–700 °C using platinum
crucibles.
2. Experimental
2.1. Materials and instrumentation
M(II) chloride (M = Zn or Cd), potassium cyanide (KCN) and 2-
aminomethylpyridine were purchased from commercial sources
and used without further purification. Elemental analyzes for C,
2.2. Crystallographic analyses
_
H, N (LECO CHNS-932 analyzer) were carried out at the TÜBITAK
Diffraction experiments were carried out at 296 K on a Stoe
IPDS diffractometer. The structure was solved by direct methods
and refined using the programs SHELXS97 and SHELXL97 [18].
All non-hydrogen atoms were refined anisotropically by full-ma-
trix least-squares methods [18]. The hydrogen atoms were placed
in geometrically idealized positions and refined as riding atoms.
Data collection: X-Area, cell refinement: X-Area, data reduction:
X-RED [19]; program(s) used for molecular graphics: ORTEP-3 for
Windows [20]; software used to prepare material for publication:
WinGX [21]. The large anisotropy for N1 in compound 2 is due to
the slightly positional disorder, this disorder is not threated and ig-
nored in the refinement.
Ankara Test and Analysis Laboratory. The FT-IR spectra of the com-
pounds were recorded in the range 4000–400 cmꢂ1 on a Perkin–El-
mer 100 FT-IR spectrometer which was calibrated using
polystyrene and CO2 bands. The samples were prepared as mulls
Table 1a
The infrared wavenumbers (cmꢂ1) of ampy in 1 and 2.a
Assignments
Liquid ampy [22]
1
2
m
m
m
m
m
m
m
m
(NH2)
(NH2)
(NH2)
(CH)
3366m
3292m
3188sh
3051m
3009m
2914m
2853m
1609w
1592vs
1569s
1474s
1435vs
1397w
1385w
1295w
1149m
1094w
1075sh
1046m
994s
3341m
3258m
3160w
–
3333m
3258m
3172w
3056sh
3027m
2917m
2862w
1605s
–
1572m
1486m
1439vs
–
1386m
1289m
1157s
–
–
–
992sh
965m
884w
816sh
777m
756vs
727m
642m
–
(CH)
–
(CH2)
(CH2)
(C@N)
2924m
2853w
1606s
1596s, sh
1571m
1487m
1438vs
–
1385m
1292w
1157s
1091w
1065w
1050sh
993sh
967w
886w
810w
778w
759vs
724m
637m
–
2.3. Syntheses of the complexes
d(NH2)
(CC)
K2[Ni(CN)4] was prepared by mixing stoichiometric amounts of
nickel(II)chloride with potassiumcyanidein water solution. [M(am-
py)2Ni(l-CN)2(CN)2]n complexes were prepared by dissolving
1 mmol (0.259 g) of K2[Ni(CN)4] in water. To this solution, 2 mmol
(0.216 g) of the 2-aminomethylpyridine dissolved in ethanol and
1 mmol of the metal chloride (ZnCl2 = 0.273 g and CdCl2 ꢀ 2H2O =
m
d(CH2)
d(CH2)
w(CH)
t(CH)
t(NH2)
m(skeletal)
m(skeletal)
m(skeletal)
m(skeletal)
m(skeletal)
Table 1b
The infrared wavenumbers (cmꢂ1) of the Ni(CN)4 unit in 1 and 2.a
Assignments
Na2[Ni(CN)4] [24]
1
2
961sh
874m, br
810sh
792sh
758vs
728w
628m
597w
t(CH2)
r(CH2), w(NH2)
B1g
Eu,
Eu,
Eu,
A2u
,
m
m
m
,
m
(CN)
2141
2132
2128
543
448
433
2155s
2137vs
2117vs
543w
480w
464w
420vs
2148m
2130vs
2117vs
538w
477w
464w
417s
(CN)
(CN)
(NiC)
p
(NiCN)
r(NH2)
r(NH2)
Eu, d(NiCN)
Eu, d(NiCN)
421
404s
ꢂ411s
ꢂ406s
a
Abbreviations used: s, strong; m, medium; w, weak; sh, shoulder; v, very. The
and refer to valence, in-plane and out-of-plane vibrations,
a
Abbreviations used:
m
, stretching; d, deformation; w, wagging; t, twisting; r,
symbols
m
,
d
p
rocking; s, strong; m, medium; w, weak; sh, shoulder; v, very; br, broad.
respectively.

222
G.S. Kürkçüog˘lu et al. / Journal of Molecular Structure 920 (2009) 220–226
0.220 g) dissolved in water were added with continuous stirring for
approximately for 5 h at 60 °C in a temperature-controlled bath. The
reaction mixture was cooled to room temperature. The crystals
formed were filtered and washed with water and ethanol and dried
in air. The freshly prepared compounds were analyzed for C, H and N
wavenumbers of the infrared bands of the ampy ligand and
Ni(CN)4 ion observed in the FT-IR spectra of the complexes are gi-
ven in (Tables 1a and 1b), together with the wavenumbers for
ampy molecule in the liquid phase [22,23] and Na2[Ni(CN)4] in
the solid state [24], respectively. A glance at Table 1a shows that
the ampy ligand shows infrared bands in the 3366–3188 cmꢂ1
with the following results. Compound [Zn(ampy)2Ni(
Anal. Found (Calcd.) (%): C, 43.07 (43.24); H, 3.67 (3.63); N, 25.21
(25.21). Compound [Cd(ampy)2Ni( -CN)2(CN)2]n, Anal. Found
l-CN)2(CN)2]n,
range are assigned to the
m(N–H) symmetric and antisymmetric
l
stretching frequencies. The absorption bands of the
m
(N–H)
(Calcd.) (%): C, 38.60 (39.10); H, 3.29 (3.28); N, 22.55 (22.80). The
C, H, N analyses were carried out for both of the complexes were
found to fit the proposed formulae well.
groups in both complexes are observed in the frequency range
3340–3170 cmꢂ1, and are significantly shifted to lower frequency
compared to the free ligand and characteristic of bond M–NH2
groups (M = Zn or Cd). Infrared spectral data for ampy in the
complexes 1 and 2 are consistent with all the vibrational fea-
tures of NH2, CN, CH2 and CH groups of a coordinated ligand,
on coordination, N–H and C–N stretching frequencies should de-
crease due to the consecutive inductive effects [25], i.e., on coor-
dination N–H and C–N bonds should become weaker. The bands
about 1590 cmꢂ1 may be assigned to the out of-plane NH2 bend-
ing vibrations and significantly shifted to higher frequency com-
3. Results and discussion
3.1. The FT-IR spectra
The FT-IR spectra of free ampy (a), complex 1 (b) and complex 2
(c) are illustrated in Fig. 1. The tentative assignments and the
Fig. 2. TG, DTG and DTA curves of 1.
Fig. 3. TG, DTG and DTA curves of 2.

G.S. Kürkçüog˘lu et al. / Journal of Molecular Structure 920 (2009) 220–226
223
Table 2
Table 5
Crystal data and structure refinement parameters for 1 and 2.
Selected geometric parameters (Å, °) for 2.
1
2
Bond length
C13–Ni1
C14–Ni1
C15–Ni1
C16–Ni1
N1–Cd1
N2–Cd1
1.872 (4)
1.859 (3)
1.869 (4)
1.852 (3)
2.302 (3)
2.346 (3)
N3–Cd1
N4–Cd1
N6–Cd1i
N8–Cd1
Cd1–N6ii
2.355 (3)
2.331 (3)
2.326 (3)
2.338 (3)
2.326 (3)
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
C16H16N8NiZn
444.45
293 (2)
C16H16N8NiCd
491.48
293 (2)
0.71073 Mo K
Orthorhombic
P212121
9.0373 (3)
13.1159 (5)
15.5365 (7)
1841.58 (12)
4
2.34
1.603
2.03–26.49
12,555
3814
a
0.71073 Mo K
Orthorhombic
P212121
9.0374 (3)
13.4163 (4)
15.7930 (5)
1914.88 (10)
4
2.11
1.705
1.99–26.50
24,491
3975
a
Bond angles
C16–Ni1–C14
C16–Ni1–C15
C14–Ni1–C15
C16–Ni1–C13
C14–Ni1–C13
C15–Ni1–C13
N1–Cd1–N6ii
N1–Cd1–N4
N6ii–Cd1–N4
N1–Cd1–N8
N6ii–Cd1–N8
173.52 (15)
90.54 (15)
88.52 (15)
89.27 (15)
92.07 (15)
176.30 (15)
101.28 (17)
168.69 (15)
89.49 (11)
87.74 (12)
91.28 (13)
N4–Cd1–N8
N1–Cd1–N2
N6ii–Cd1–N2
N4–Cd1–N2
N8–Cd1–N2
N1–Cd1–N3
N6ii–Cd1–N3
N4–Cd1–N3
N8–Cd1–N3
N2–Cd1–N3
95.54 (10)
72.47 (11)
88.22 (11)
104.76 (9)
159.68 (10)
98.31 (17)
160.10 (12)
70.76 (11)
92.98 (12)
94.37 (11)
b (Å)
c (Å)
V (Å3)
Z
Absorption coefficient (mmꢂ1
)
Dcalc (Mg m3)
Theta range for data collection (°)
Measured reflections
Independent reflections
Flack parameter
Absorption correction
Refinement method
ꢂ0.017(14)
0.012(18)
Integration Stoe XRED [19]
Full-matrix least-squares on F2
Symmetry codes: (i) ꢂx, y ꢂ 1/2, ꢂz + 1/2; (ii) ꢂx, y + 1/2, ꢂz + 1/2.
Final R indices [I > 2
Final R indices (all data)
r(I)]
Rint = 0.053
R1 = 0.031
wR2 = 0.077
0.99
0.49
ꢂ0.38
Rint = 0.071
R1 = 0.023
wR2 = 0.056
1.05
0.27
ꢂ0.36
Goodness0-of-fit on F2
Table 6
D
D
qmax (eAÅꢂ3
)
Hydrogen-bond geometry (Å, °) for 2.
0
qmin (eAÅꢂ3
)
DꢂHꢀ ꢀ ꢀA
DꢂH
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
\DꢂHꢀ ꢀ ꢀA
N1–H1Cꢀ ꢀ ꢀN5
N1–H1Dꢀ ꢀ ꢀN5iii
N3–H3Aꢀ ꢀ ꢀN7iv
N3–H3Bꢀ ꢀ ꢀN5iii
0.90
0.90
0.90
0.90
2.59
2.47
2.40
2.55
3.272 (5)
3.252 (7)
3.190 (5)
3.279 (5)
133
145
146
139
Table 3
Selected geometric parameters (Å, °) for 1.
Bond length
Symmetry codes: (iii) x + 1/2, ꢂy + 1/2, ꢂz + 1; (iv) ꢂx + 1, y + 1/2, ꢂz + 1/2.
C13–Ni1
C14–Ni1
C15–Ni1
C16–Ni1
N1–Zn1
1.864 (4)
1.853 (4)
1.877 (4)
1.858 (4)
2.130 (3)
N2–Zn1
N3–Zn1
N4–Zn1
N6–Zn1i
N8–Zn1ii
2.166 (3)
2.183 (3)
2.156 (3)
2.197 (3)
2.148 (3)
The
m
(CN) vibrations are the most important absorption bands
(CN) vibrational peaks in the FT-IR
for complexes 1 and 2 since
m
Bond angles
spectra are used to reveal the bridging formation in the poly-
meric complexes. Two strong and sharp absorption bands at
2155 and 2137 cmꢂ1 in the FT-IR spectrum of complex 1 can
easily be attributed to bridging cyano and terminal cyano bands,
respectively, and the bands at 2148 and 2130 cmꢂ1 in the FT-IR
spectrum of complex 2 correspond to bridging cyano and termi-
nal cyano bands, respectively (Table 1b). The observed differ-
ences in these two cyano stretching vibrations are important
evidence for formation of cyano-bridged complexes with the
bridging cyano wavenumber higher than the terminal cyano
[26]. This shift was attributed to the kinematic coupling placing
a mechanical constraint upon the bridging cyano by the second
metal [26–31]. In the other words, such frequency shifts are
attributed to the mechanical coupling of the internal modes of
Ni(CN)4 with the M–NC vibrations (M = Zn or Cd). It follows that
the N-termini of the Ni(CN)4 group are bound to a M atom in
the complexes investigated.
C14–Ni1–C16
C14–Ni1–C13
C16–Ni1–C13
C14–Ni1–C15
C16–Ni1–C15
C13–Ni1–C15
N1–Zn1–N8iii
N1–Zn1–N4
N8iii–Zn1–N4
N1–Zn1–N2
N8iii–Zn1–N2
172.50 (16)
91.47 (16)
87.84 (16)
88.76 (16)
92.47 (16)
175.81 (16)
97.01 (16)
171.49 (15)
91.36 (11)
77.73 (14)
89.10 (12)
N4–Zn1–N2
101.00 (10)
95.78 (15)
167.19 (12)
75.83 (11)
92.89 (12)
86.29 (14)
89.61 (13)
95.29 (11)
163.69 (11)
91.96 (13)
N1–Zn1–N3
N8iii–Zn1–N3
N4–Zn1–N3
N2–Zn1–N3
N1–Zn1–N6iv
N8iii–Zn1–N6iv
N4–Zn1–N6iv
N2–Zn1–N6iv
N3–Zn1–N6iv
Symmetry codes: (i) ꢂx + 1, y + 1/2, ꢂz + 1/2; (ii) x + 1, y, z; (iii) x ꢂ 1, y, z; (iv) ꢂx + 1,
y ꢂ 1/2, ꢂz + 1/2.
Table 4
Hydrogen bond geometry (Å, °) for 1.
DꢂHꢀ ꢀ ꢀA
DꢂH
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
\DꢂHꢀ ꢀ ꢀA
N1–H1Cꢀ ꢀ ꢀN7iv
N1–H1Dꢀ ꢀ ꢀN7v
N3–H3Aꢀ ꢀ ꢀN5
N3–H3Bꢀ ꢀ ꢀN7v
0.90
0.90
0.90
0.90
2.68
2.42
2.44
2.45
3.368 (6)
3.202 (6)
3.200 (5)
3.186 (5)
134
145
143
139
3.2. Thermal analyses
Thermal behavior of the complexes was studied by TG, DTG and
DTA in the temperature range 50–700 °C in the static air atmo-
sphere. Thermal decomposition curves of 1 and 2 are presented
in Figs. 2 and 3, respectively. The complexes are thermally stable
up to 195 and 215 °C, respectively, and then begin to decompose.
The first between 195–419 °C for 1 and 215–431 °C for 2 corre-
spond to release of one ampy, which are accompanied by endo-
thermic DTA peaks at 253, 284 and 381 °C for 1 and 243, 288
and 343 °C for 2. The mass loss values of 24.52% for 1 and 22.94%
for 2 are in good agreement with the calculated mass loss value
of an ampy molecule (24.33% for 1 and 22.00% for 2). The following
stages, remaining an ampy and four cyano groups decomposes be-
Symmetry codes: (iv) ꢂx + 1, y ꢂ 1/2, ꢂz + 1/2; (v) ꢂx + 3/2, ꢂy + 1, z + 1/2.
pared to the free ligand. The relatively weak bands between
3050 and 2853 cmꢂ1 are assigned to the
m(CH) mode of the aro-
matic and methylene groups. Other significant bands are the
m
(CC) at 1570 cmꢂ1
, m(skeletal) at 1149, 1094, 1075, 1046 and
994 cmꢂ1 and the out of-plane C–H bend in the ring at
756 cmꢂ1. As seen in Table 1a, several bands are assigned to
CH and CH2 groups (antisymmetric and symmetric stretching)
in different environments. Infrared spectral data show that the
ampy ligand is coordinated in a tetradentate manner.

224
G.S. Kürkçüog˘lu et al. / Journal of Molecular Structure 920 (2009) 220–226
lows the order: Cd(II), 215 °C > Zn(II), 195 °C in static air atmo-
sphere. The initial temperature of decomposition of complex 2 is
increase due to ionic radii of the Cd(II) ion bigger than Zn(II) ion.
3.3. Structure of the complexes
Crystal data and refinement of result are presented in Table 2.
Selected bond lengths and angles together with the hydrogen
bonding geometry for 1 and 2 are collected in Tables 3–6, respec-
tively. The overall structures of 1 and 2 are isostructural, and slight
structural differences due to replace from Zn(II) to Cd(II) can be ob-
served for 1 and 2. The molecular structures of 1 and 2 with the
atom labeling are shown Fig. 4a and b, respectively. The crystallo-
graphic analyses revealed that the complexes, [Zn(ampy)2Ni(
l-
CN)2(CN)2]n (1) and [Cd(ampy)2Ni( -CN)2(CN)2]n (2), have
l
a
cyanide-bridged polymeric chain structure in which nickel(II) is
coordinated by four cyanide ligands (two cyano groups are termi-
nal and two cyano groups (in cis fashion) are bridged), and M(II)
(M = Zn(II) or Cd(II)) ion is coordinated by the two bidentate ampy
ligands, two bridging cis cyanide ligands. The coordination envi-
ronment of the M(II) ion can be described as distorted octahedral
geometry, whereas around the Ni(II) centre has square planer
geometry. The Ni–C coordination bond distances of 1.853(4) and
1.877(4) Å for 1 and 1.852(3) and 1.872(4) Å for 2 are similar that
found in the [Cu(N-Eten)2][Ni(CN)4] [32], [Cu(dpt)Ni(CN)4] [33],
[Zn(en)2Ni(CN)4]n and [Cd(en)2Ni(CN)4]n [34].
The Cd1N bond distances of 2.326(3) and 2.355(3) Å for 2 is sig-
nificantly longer than those of 2.130(3) and 2.197(3) Å for 1, which
correspond to the difference of ion radii [35], whereas these bond
lengths are found to be similar to those of our previously reported
[Cd(H2O)(2-mpz)Ni(CN)4]n (2.349(3) Å) [36] and [Cd(teta)-
Ni(CN)4]n (2.349(3) Å) [37] complexes and [Zn(en)2Ni(CN)4]n
(2.107(5) and 2.138(5) Å) [34], [Cd(en)2Ni(CN)4]n (2.313(5) and
(2.345(5) Å)
[34],
trans-[Cd(sac)2(ampy)2]
(2.316(1)
and
2.319(2) Å) [12] and [CdCl2(ampy)]n (2.345(6) and 2.332(5) Å)
[38]. However, these bond distances are somewhat shorter that
found in [Zn(teta)Ni(CN)4]n (2.349(3) Å) [39], [Zn(hydeten)2Pd
(CN)4]n (2.215(2) Å) [40], [Zn(hydeten)2Pt(CN)4]n (2.33(1) Å) and
[Cd(hydeten)2Pt(CN)4]n (2.38(3) Å) [41].
The intermolecular M1M1i and M1M1ii (M = Zn(II), Cd(II), i:
1 ꢂ x, 1/2 + y, 1/2 ꢂ z; ii: 1 + x, y, z) distances are 7.235 and
9.037 Å for 1 and 8.657 and 8.551 Å for 2, respectively, intramolec-
ular M1M1iii (iii: ꢂx, 1/2 + y, 1/2 ꢂ z) distances is also 9.812 Å for 1
and 9.965 Å for 2.
Fig. 4. An ORTEP-3 drawing of complexes with the atom-numbering scheme.
Displacement ellipsoids are drawn at the 50% probability level (a for 1 and b for 2).
tween 419 and 504 °C for 1 and 430 and 512 °C for 2. The total
mass loss of all decomposition process is 61.29% (Calcd. 64.88%)
for 1 and 58.67% (Calcd. 58.68%) for 2 suggest that MO + NiO is
the end product.
On the basis of the first decomposition temperatures of the
complexes, the thermal stability of the isostructural complexes fol-
The crystal packing were formed by intermolecular hydrogen
bonding of the between one-dimensional zigzag chains. This weak
hydrogen bond is observed between NH2 group of ampy ligand
and N5, N7 atom of cyano groups [N1ꢀ ꢀ ꢀN7iv = 3.368(6)°,
N3ꢀ ꢀ ꢀN5 = 3.200(5)° for
1
((iv) ꢂx + 1, y ꢂ 1/2, ꢂz + 1/2) and
Fig. 5. A view of the one-dimensional zigzag chains of the complexes.

G.S. Kürkçüog˘lu et al. / Journal of Molecular Structure 920 (2009) 220–226
225
N1ꢀ ꢀ ꢀN5iii = 3.279(5)°, N3ꢀ ꢀ ꢀN7iv = 3.190(5)° and N1ꢀ ꢀ ꢀN5iii
=
CgB: N(2)–C(2)–C(3)–C(4)–C(5)–C(6)). All these intermolecular
interactions result in the formation of three dimensionally.
Non-covalent interactions are very important in biological
structure, supramolecular chemistry and molecular recognition.
3.252(7)°, (iii) x + 1/2, ꢂy + 1/2, ꢂz + 1; (iv) ꢂx + 1, y + 1/2, ꢂz + 1/
2] (Fig. 5). There are C–Hꢀ ꢀ ꢀ
p
interaction between the C5–H5ꢀ ꢀ ꢀCgA
and C10–H10ꢀ ꢀ ꢀCgB (CgA: N(4)–C(8)–C(9)–C(10)–C(11)–C(12) and
Fig. 6. (a) The hydrogen-bonding and C–Hꢀ ꢀ ꢀp interactions; (b) Niꢀ ꢀ ꢀp interactions of the complexes.

226
G.S. Kürkçüog˘lu et al. / Journal of Molecular Structure 920 (2009) 220–226
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4. Conclusion
We have successfully synthesized the two novel three-dimen-
sional cyano-bridged heteronuclear polymeric complexes, [Zn(am-
py)2Ni(l-CN)2(CN)2]n and [Cd(ampy)2Ni(l-CN)2(CN)2]n. The Ni(II)
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planar geometry and the Zn(II) or Cd(II) ion exhibits a distorted
octahedral coordination by two bidentate ampy ligands and two
bridging cyano groups as a cis position. Vibration assignments
were given for all the observed bands and the spectral feature also
supported to the structure of polymeric complexes. The crystal
packing of complexes are a composite of intermolecular hydrogen
bonding, C–Hꢀ ꢀ ꢀ
p
and Ni(II)ꢀ ꢀ ꢀ
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p
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Supplementary material
CCDC Nos. 693905 and 693906 contain the supplementary crys-
tallographic data for this paper. 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:
deposit@ccdc.cam.ac.uk.
_
[36] G.S. Kürkçüog˘lu, O.Z. Yeßsilel, I. Kavlak, O. Büyükgüngör, Struct. Chem. 19
(2008) 879.
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[39] G.S. Kürkçüog˘lu, O.Z. Yeßsilel, I. Kavlak, O. Büyükgüngör, Z. Anorg. Allg. Chem.
(2008), doi:10.1002/zaac.200800337.
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Acknowledgement
_
_
[41] A. Karadag˘, I. Önal, A. Sßenocak, I. Uçar, A. Bulut, O. Büyükgüngör, Polyhedron
27 (2008) 223.
This work has been supported by the Research Fund of Eskißsehir
Osmangazi University. Project Number 200719025.
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