New saccharinate complexes with 3,3′-azobispyridine ligand: synthesis, characterization, and spectroscopic properties

Article abstract of DOI:10.1080/00958972.2017.1360489

The new metal complexes with saccharinate (sac) and 3,3′-azobispyridine (3,3′-abpy), [Ni(H₂O)₄(3,3′-abpy)₂](sac)₂ (1), [Cu(sac)₂(H₂O)(μ-3,3′-abpy)]_n (2), [Zn(H₂O)₄(3,3′-abpy)₂](sac)₂ (3), [Cd(sac)₂(H₂O)₂(μ-3,3′-abpy)]_n (4), and [Hg₂(μ-sac)₂(sac)₂(μ-3,3′-abpy)(3,3′-abpy)₂]_n (5), were synthesized and characterized by IR spectra, elemental analysis, and single-crystal X-ray diffraction. Spectroscopic (UV–vis and photoluminescence) and thermal properties were also investigated. Single-crystal X-ray analysis reveals that Ni(II) and Zn(II) are coordinated by four aqua ligands and two nitrogens of 3,3′-abpy, while sac is a counter-ion in 1 and 3. In 2, Cu(II) and all ligands are linked by coordination bonds and 3,3′-abpy ligands connect the Cu(II) centers forming a 1-D coordination polymer. In 4, sac N-coordinated to Cd(II) and distorted octahedral geometry of Cd(II) ion is completed by two aqua and bridging 3,3′-abpy ligands. In 5, sac bridges two Hg(II) ions to generate dinuclear [Hg₂(μ-sac)₂] units. These dinuclear units are connected by 3,3′-abpy to form a 1-D coordination polymer. The photoluminescence spectra of 3 and 5 show blue fluorescent emission bands, and these emissions can probably be assigned to intraligand fluorescent emissions. Thermal decompositions of the compounds are also discussed. For all complexes, magnetic susceptibility measurements show expected magnetic behavior.

Full text of DOI:10.1080/00958972.2017.1360489

Journal of Coordination Chemistry
ISSN: 0095-8972 (Print) 1029-0389 (Online) Journal homepage: http://www.tandfonline.com/loi/gcoo20
New saccharinate complexes with 3,3’-
azobispyridine ligand: Synthesis, characterization
and spectroscopic properties
Figen Arslan Biçer, Semiha Yildirim, Wolfgang Kaim & Martina Bubrin
To cite this article: Figen Arslan Biçer, Semiha Yildirim, Wolfgang Kaim & Martina
Bubrin (2017): New saccharinate complexes with 3,3’-azobispyridine ligand: Synthesis,
characterization and spectroscopic properties, Journal of Coordination Chemistry, DOI:
10.1080/00958972.2017.1360489
To link to this article: http://dx.doi.org/10.1080/00958972.2017.1360489
View supplementary material
Accepted author version posted online: 27
Jul 2017.
Submit your article to this journal
Article views: 1
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=gcoo20
Download by: [Universite Laval]
Date: 31 July 2017, At: 01:41

Publisher: Taylor & Francis
Journal: Journal of Coordination Chemistry
DOI: http://doi.org/10.1080/00958972.2017.1360489
New saccharinate complexes with 3,3’-azobispyridine ligand: Synthesis,
characterization and spectroscopic properties
FIGEN ARSLAN BIÇER1†, SEMIHA YILDIRIM‡, WOLFGANG KAIM§ and MARTINA BUBRIN§
†
‡
§
Department of Chemistry, Karabük University, TR-78050 Karabük, Turkey
Department of Chemistry, Gebze Technical University, TR-41400 Gebze, Kocaeli, Turkey
Institute of Inorganic Chemistry, Stuttgart University, Pfaffenwaldring 55, D-70550 Stuttgart, Germany
The new metal complexes with saccharinate (sac) and 3,3'-azobispyridine (3,3’-abpy),
[Ni(H O) (3,3'-abpy) ](sac) (1), [Cu(sac) (H O)(µ-3,3'-abpy)] (2), [Zn(H O) (3,3'-abpy) ](sac)
2 4 2 2 2 2 n 2 4 2 2
(
3), [Cd(sac) (H O) (µ-3,3'-abpy)] (4) and [Hg (µ-sac) (sac) (µ-3,3'-abpy)(3,3'-abpy) ] (5),
2
2
2
n
2
2
2
2 n
were synthesized and characterized by IR spectra, elemental analysis, and single crystal X-ray
diffraction. Spectroscopic (UV-vis. and photoluminescence) and thermal properties were also
investigated. Single crystal X-ray analysis reveals that Ni(II) and Zn(II) are coordinated by four
aqua ligands and two nitrogens of 3,3'-abpy, while sac is a counter-ion in 1 and 3. In 2, Cu(II)
and all ligands are linked by coordination bonds and 3,3'-abpy ligands connect the Cu(II) centers
forming a one-dimensional coordination polymer. In 4, sac N-coordinated to Cd(II) and distorted
octahedral geometry of Cd(II) ion is completed by two aqua and bridging 3,3'-abpy ligands. In 5,
sac bridges two Hg(II) ions to generate dinuclear [Hg (µ-sac) ] units. These dinuclear units are
2
2
connected by 3,3'-abpy to form a 1D coordination polymer. The photoluminescence spectra of 3
and 5 show blue fluorescent emission bands, and these emissions can probably be assigned to
intraligand fluorescent emissions. Thermal decompositions of the compounds are also discussed.
For all complexes, magnetic susceptibility measurements show expected magnetic behavior.
Keywords: 3,3'-Azobispyridine; Saccharinate complexes; Coordination polymers
1
. Introduction
Saccharine, the classical artificial sweetener, forms a number of complexes with different metal
1
Corresponding author. Email: farslan@karabuk.edu.tr
1

ions. It contains three donor groups, the imino nitrogen, the carbonyl and the sulfonyl oxygens
1-4], making it an interesting ligand for coordination chemistry [2]. The deprotonated form of
[
this molecule, saccharinate, is usually connected to metal ions via the negatively charged
nitrogen [5-7].
3
,3'-abpy derived from the 3-aminopyridine contains four electron donors, the two
pyridine nitrogens and the azo groups. Only the pyridine nitrogens are involved in coordination
in 1-5. Ligands possessing the azo functionality have extremely low-lying π* orbitals and are
strongly π-accepting [8] so they are efficient to stabilize low metal oxidation states [9]. Also,
metal complexes involving the azo group are highly colored and used as dyestuffs in various
applications [10].
Our interest has been focused on the metal–saccharinate–azobispyridine system, in which
azobispyridines play a role in construction of supramolecular architectures organized by metal
coordination and/or supramolecular contacts such as hydrogen-bonding or π-π interaction [11-
1
6]. Since 3,3'-abpy (scheme 1) possesses a structure with a π conjugated system and two
coordinatively active nitrogens, it is especially suited to connect remote metal centers in the
stepwise construction of polynuclear arrangements [15, 17, 18]. The pyridine nitrogens are more
basic and are more accessible for coordination for steric reasons [19]. Azo compounds are used
as organic dyes and pigments, in indicators, electro-optical devices, for reversible data storage,
photochemical switches and therapeutic and drug delivery agents [20-26]. Therefore, the
synthesis of azo compounds has attracted great attention in both pure and applied research.
O
O
O
C
S
O
C
S
M
O
N
C
S
O
O
N
O
N
O
M
M
1
and 3
2, 4 and 5
5
2

M
N
N
N
N
N
N
N
N
M
M
1
, 3 and 5
2, 4 and 5
Scheme 1. Coordination modes of the saccharinate and 3,3'-azobispyridine ligands.
The aim of this work is to prepare new mixed-ligand saccharinate complexes of Ni(II),
Cu(II), Zn(II), Cd(II) and Hg(II) with 3,3'-azobispyridine and to analyze their structural and
spectroscopic characteristics using single crystal X-ray diffraction, spectroscopic techniques (IR,
UV-Vis, photoluminescence) and thermal analysis. Many saccharinate complexes containing
N-donor co-ligands have been synthesized [1-4], but complexes with azobispyridine derivatives
have not been reported.
2
2
. Experimental
.1. Materials and measurements
All chemicals used were of analytical reagent quality. The 3,3'-abpy was synthesized by
oxidation of the 3-aminopyridine with NaOCl according to the Kirpal-Reiter method [10].
Elemental analyses were carried out on a CHNS-932 (LECO) Elemental
Analyzer. The UV-vis. spectra of the complexes were obtained with a Perkin Elmer Lambda 35
UV-vis. spectrometer from 900-200 nm. Photoluminescence spectra for the solid complex
samples were recorded on a Perkin-Elmer LS-55 spectrophotometer. IR spectra were recorded on
-1
a Bruker Tensor 27 FT/IR spectrophotometer using KBr pellets and operating at 4000-400 cm .
A Perkin Elmer Diamond thermal analyzer was used to record TG, DTA and DTG curves in
-1
static air at a heating rate of 10 °C·min from 30-1000 °C using platinum crucibles. Highly
sintered α-Al O was used as a reference. The X-ray diffraction data were collected with a
2
3
Bruker Kappa Apex2duo diffractometer. The structures were solved and refined by full-matrix
2
least-squares techniques on F by using the SHELX-97 program [27]. Absorption corrections
were done by the multiscan technique. All non-hydrogen atoms were refined anisotropically. All
non-water hydrogens were included in the refinement process by using a riding model.
3

2
.2. Synthesis of the complexes
For synthesis of mixed-ligand saccharinate complexes with transition metal ions, it is a common
strategy to apply [M(sac) (H O) ]·2H O [M = Ni(II), Cu(II), Zn(II), Cd(II) [28, 29], and
2
2
4
2
[
Hg(sac) ] [30, 31] as synthetic precursors. In order to prepare it, sodium saccharinate was
2
dissolved in water and added to hot water solution of acetate salts of each metal. The mixture
was stirred at 80 °C for 3 h and then cooled to room temperature. The aqua-saccarinate
complexes that were obtained were filtered out and washed with water and dried in a vacuum.
2
.2.1. Synthesis of 1. A solution of 3,3'-abpy (1.0 mmol) in ethanol was added dropwise to a
stirred solution of [Ni(sac) (H O) ]·2H O in ethanol (2.0 mmol). A few drops of DMSO were
2
2
4
2
added to the reaction mixture which was heated under reflux for 2 h. Crystals suitable for X-ray
analysis were obtained by slow evaporation over a period of one week. For orange 1 (yield
7
3
3.2%). Anal. Calc. for C H N O S Ni (1): C, 47.29; H, 3.74; N, 15.86. Found: C, 46.86; H,
34 32 10 10 2
.99; N, 15.86.
2
.2.2. Synthesis of 2. A solution of 3,3'-abpy (1.0 mmol) in ethanol was added dropwise to a
stirred aqueous solution of [Cu(sac) (H O) ]·2H O (2.0 mmol) and refluxed for 2 h. Crystals
2
2
4
2
suitable for X-ray analysis were obtained by slow evaporation over a period of 5 days. For
orange 2 (yield 53.0%) Anal. Calc. for C H N O S Cu (2): C, 45.75; H, 2.88; N, 13.34. Found:
2
4
18
6
7 2
C, 45.85; H, 3.23; N, 13.09.
2
.2.3. Synthesis of 3. A solution of 3,3'-abpy (1.0 mmol) in ethanol was added dropwise to a
stirred solution of [Zn(sac) (H O) ]·2H O in ethanol (2.0 mmol). A few drops of water were
2
2
4
2
added to the reaction mixture, which was heated under reflux for 2 h and then filtered. Crystals
suitable for X-ray analysis were obtained by slow evaporation over a period of one week in
methanol/water (50%). For red 3 (yield 55.9%). Anal. Calc. for C H N O S Zn: C, 46.93; H,
3
4
32 10 10 2
3
.71; N, 16.10 %. Found: C, 47.00; H, 3.89; N, 15.72 %.
2
.2.4. Synthesis of 4. A solution of 3,3'-abpy (1.0 mmol) in ethanol was added dropwise to a
stirred solution of [Cd(sac) (H O) ]·2H O in methanol (1.0 mmol). A few drops of water were
2
2
4
2
4

added to the reaction mixture until the precipitate was dissolved and then the mixture was heated
under reflux for 2 h. Crystals suitable for X-ray analysis were obtained by slow evaporation over
8
days. For red 4 (yield 64.3 %). Anal. Calc. for C H N O S Cd: C, 41.36; H, 2.89; N, 12.06
24 20 6 8 2
%. Found: C, 41.86; H, 3.25; N, 12.05 %.
2
.2.5. Synthesis of 5. A solution of 3,3'-abpy (2.0 mmol) in ethanol was added dropwise to a
stirred solution of [Hg(sac) ] in THF (1.0 mmol). A few drops of DMSO were added to the
2
reaction mixture until the precipitate dissolved and the mixture was heated under reflux for 2 h.
Crystals suitable for X-ray analysis were obtained by slow evaporation for two weeks. For red 5
(
yield 82.4%). Anal. Calc. for C H N O S Hg: C, 41.40; H, 2.40; N, 13.32 %. Found: C, 41.28;
29 20 8 6 2
H, 2.15; N, 12.91 %.
3
3
. Results and discussion
.1. Characterization
The elemental analyses are consistent with the assigned formulas. Selected IR data for the
complexes are listed in table S1.
−
1
The strong and broad absorption bands between 3383 and 3508 cm are characteristic of
-1
ν(OH) vibrations of aqua ligands for 1-4. The relatively weak bands at 3133–3019 cm are due
to ʋ(CH). In metal complexes of sac, the stretches of the carbonyl and sulfonyl groups are the
most employed IR frequencies, since the coordination mode of sac can be deduced from the band
positions of these groups. The absorption bands of the carbonyl group of 1 and 3 in which sac is
-1
-1
uncoordinated are strong bands at 1618 cm and 1620 cm , respectively, significantly shifted to
lower frequency compared to 2, 4 and 5. Intra- and intermolecular hydrogen bonding interactions
involving the carbonyl group shift these bands to lower frequencies [31]. The carbonyl bands
-1
centered at 1650 cm usually correspond to monodentate coordination of sac through the imino
-1
N atom [32, 33]. In the spectra of 2 and 4 these bands were observed at 1643 and 1634 cm ,
respectively. This shift indicates that coordination of N of sac to the metal reduces the electron
density in the CO bond [34] and intra- and intermolecular hydrogen bonding interactions occur
for the carbonyl group [31]. Single crystal X-ray analysis for 5 reveals that sac is both
N-coordinated (monodentate) and both N- and O-coordinated (bridging). Two absorption bands
are expected for carbonyl groups but in spectra of 5, the carbonyl groups are a sharp band at
5

-1
-1
1
663 cm . The asymmetric SO stretches are observed at 1246-1261 cm ; the symmetrical
2
-1
-1
stretch of the SO is at ca. 1132-1152 cm . Additional peaks at 1342 and 957 cm are attributed
2
to symmetric and asymmetric stretches of the CNS moiety of sac, respectively. Bands around
-1
1
429 cm are assigned to N=N vibrations of the 3,3'-abpy ligand. C=N vibrations of 3,3'-abpy
-1
are at ca. 1578 cm .
3
.2. Description of crystal structures
A summary of crystallographic data, experimental details, and refinement results for 1-5 are
given in table 1. Selected bond lengths, angles and hydrogen bonding parameters are given in
tables 2 and 3, respectively.
3
.2.1. [Ni(H O) (3,3'-abpy) ](sac) (1). In 1, nickel is octahedrally coordinated by two pyridyl
2 4 2 2
nitrogens from 3,3'-abpy and four water molecules in an all-trans alignment (figure 1). The four
water oxygens form the equatorial plane. The 3,3'-abpy molecules occupy axial positions.
In an aqua-saccharinate complex, the saccharinate ligand is N-bonded to Ni(II) [28], but
substitution of the sac molecules by 3,3'-abpy gives a product in which saccharinate is not
coordinated. The crystals are stabilized by intermolecular hydrogen bonds and π(3,3'-abpy)–
π(3,3'-abpy) interaction (figure 2). Sac anion outside the coordination sphere is the acceptor in a
strong intermolecular hydrogen bond with coordinated water (figure 2).
The hydrogens of aqua ligands form strong intermolecular hydrogen bonds with the
nitrogens of 3,3'-abpy, sulfonyl oxygens of sac, and carbonyl oxygen of sac. There are π-π
i
ii
i
iii
interactions between 3,3'-abpy rings [Cg(1) ····Cg(2) = 3.7181 Å, Cg(1) ····Cg(2) = 3.7181 Å;
Cg1 = C1-C2-C3-C4-C5-N1 and Cg2 = C10-C11-C12-C13-C14-N5. ((i) –x, -y, -z; (ii) -x, y,
-1-z; (iii) x, y, 1+z) Further, there are O-H····π and two C-H····π interactions between sac, 3,3'-
abpy and aqua ligands (figure 2). [O(2)-H(2B)····Cg(3) =2,92Å; C(3)-H(3B)····Cg(4) = 2.97 Å
and C(14)-H(14A)····Cg(4) = 2.98 Å; Cg3= S(2)-N(2)-C(20)-C(21)-C(22); Cg(4) = C(21)-C(22)-
C(23)-C(24)-C(25)-C(26)].
3
.2.2. [Cu(sac) (H O)(µ-3,3'-abpy)] (2). Cu(II) is coordinated with four nitrogens (two from
2 2 n
3
,3′-abpy and two from two saccharinates) and one water molecule. Bridging of Cu(II) centers
by 3,3'-abpy ligands results in a one-dimensional coordination polymer (figure 3). The closest
6

metal-metal distance between ligand-bridged metal centers is 10.451 Å. The 3,3'-abpy has planar
structure, but deviated from planarity in [Cu(sac) (H O)(µ-3,3'-abpy)] because of intramolecular
2
2
n
hydrogen bonds.
Selected bond lengths and angles of 2 are given in table 2. The coordination geometry
around Cu(II) is distorted square-pyramidal with a τ value of 0.029 (The τ parameter is used to
describe the structure of five-coordinate compounds: τ = 0 for an ideal square-pyramid and τ = 1
for an ideal trigonal-bipyramid) [35]. The bridging 3,3'-abpy ligand links neighboring Cu(II)
centers to form a 1-D polymer with a Cu···Cu separation of ca. 13.30 Å, as illustrated in figure 3.
The crystal packing diagram of 2 is shown in figure 4. The carbonyl O of sac forms
strong intermolecular hydrogen bonds with aqua ligands. Further, there are four C-H···π
interactions between sac and 3,3'-abpy ligands. [C(3A)-H(3AA)···Cg(2) = 2.83 Å;
C(3)-H(3A)···Cg(1) = 2.78 Å; C(24)-H(24A)···Cg(2) = 2.73 Å and C(24B)-H(24B)···Cg(1) =
2
.86 Å; Cg(1) = S(2)-N(2)-C(20)-C(21)-C(22) and Cg(2) = S(2C)-N(2B)-C(20B)-C(21B)-
C(22B)].
3
.2.3. [Zn(H O) (3,3'-abpy) ](sac) (3). X-ray analysis indicates that the asymmetric unit of 3
2 4 2 2
contains one sac, half of a Zn(II), one 3,3'-abpy, and two aqua ligands (figure 5). The Zn(II) ion
is octahedrally coordinated by two nitrogens to from 3,3'-azobispyridine ligands and four water
molecules in an trans alignment (figure 5). Saccharinate is a counter anion outside the
i
i
coordination sphere. The basal plane is defined by O1, O1 , O2 and O2 from the four aqua
i
ligands with axial positions occupied by N1 and N1 of 3,3'-abpy ((i) -x, -y, 1-z). The Zn1-N1,
Zn1-O1 and Zn1-O2 distances are 2.556(3), 1.979(2) and 1.983(2) Å, respectively. The N5‒‒S1
and N5‒‒C11 bond lengths of sac (mean values of 1.547(3) and 1.584(4) Å, respectively) are
similar to corresponding distances (1.596 and 1.354 Å) in sodium saccharinate [36]. The pyridine
rings of 3,3'-abpy are planar. The dihedral angle between the N2 and N3 pyridine rings is
1
79.8(2)°.
The crystal packing is mainly stabilized by intra- and intermolecular hydrogen bonds and
π···π interactions. As shown in figure 6(a), adjacent units are connected by O2-H2B···N4
hydrogen bonding between aqua and nitrogen atom of 3,3ʹ-abpy ligands and π···π close stacking
between 3,3'-abpy rings (Cg(1)···Cg(2) = 3.184 Å; Cg1 = N1-C1-C2-C3-C4-C5 and Cg2 =
N4-C6-C7-C8-C9-C10) to form a 1D chain. The 1D chains are linked by O-H···O hydrogen
7

bonding interactions between hydrogens of aqua ligands and carbonyl and sulfonyl oxygens of
adjacent sac ions to construct a 2D supramolecular structure (figure 6(b)). These 2D layers are
extended to form a three-dimensional supramolecular network through CH···π interaction
between C3H3 and phenyl ring.
3
.2.4. [Cd(sac) (H O) (µ-3,3'-abpy)] (4). Single-crystal X-ray analysis reveals that 4
2 2 2 n
crystallizes in a monoclinic system with space group P2 /n. The asymmetric unit of 4 contains
1
one Cd(II), one sac, one aqua and a half of 3,3ʹ-abpy ligands. In 4, the 3,3'-abpy ligands bridge
Cd(II) centers through nitrogens to form a one-dimensional polymeric structure (figure 7(a)).
The octahedral coordination at each cadmium is completed by aqua and N-bonded sac ligands,
which coordinate trans to each Cd(II) (figure 8). The distance of two Cd ions separated by
bridging 3,3'-abpy is 12.20 Å. The Cd1-N3 bond distance of 2.3208(13) Å (table 2) is compatible
with that found in [Cd(sac) (bipy) ] [4] and [Cd (sac) (Im) ] [37].
2
2
2
4
4
The crystal packing diagram of 4 is shown in figure 7(b). The carbonyl oxygen of sac
forms strong intermolecular hydrogen bonds with the aqua ligands to form two-dimensional
structures (figure 7(c)).
3
.2.5. [Hg (µ-sac) (sac) (µ-3,3'-abpy)(3,3'-abpy) ] (5). The crystal structure of 5 with atom
2 2 2 2 n
labeling is shown in figure 9 and selected bond lengths are given in table 2. The asymmetric unit
of 5 contains one Hg(II), two sac and one and a half 3,3'-abpy ligands. The coordination
geometry around Hg(II) center is distorted trigonal-bipyramidal with a τ value of 0.7. In 5, one of
the sac anions is µ-bridging to connect two mercury ions through the imino N and carbonyl O,
forming dinuclear [Hg (µ-sac) ] units. These dimeric units are bridged by neutral 3,3'-abpy
2
2
ligands, leading to a one-dimensional coordination polymer (figure 10). The other sac anion
connects to mercury via the negatively charged nitrogen. The closest Hg-Hg contact is 11.412 Å
in the polymeric chain. There are also two different types of 3,3'-abpy ligands in this complex.
The first uses only one terminal nitrogen to coordinate the Hg(II) while the second 3,3'-abpy is a
bridge.
The molecular packing of the complex is stabilized by two π···π (figure 11) and two
i
ii
S=O···π interactions (figure 10) [Cg(1)‒Cg(1) = 3.779(2) Å, Cg(2)‒Cg(2) = 3.9946;
8

iii
3
S1O3···Cg3 = 3.515 Å and S2-O6···Cg4 = 3.532(3) Å, (i) -x, y, ½-z; (ii) 1-x, y, / -z; (iii) ½-x,
2
½
-y, 1-z, Cg1 = N1‒C1‒C2‒C3‒C4‒C5, Cg2 = C17‒C18‒C19‒C20‒C21‒C22, Cg3 =
S2N8C23‒C24‒C29 and Cg4 = N5‒C11‒C12‒C13‒C14‒C15].
3
.3. UV-Vis, photoluminescent, and thermal properties
Electronic spectra were recorded in DMF solution from 300-900 nm. The electronic spectrum of
-1
-1
3
,3'-abpy consists of two bands, 319 nm (ε = 10000 Lmol cm ), attributed to a π-π* transition,
-1
-1
and 445 nm (ε = 300 Lmol cm ), attributed to an n-π* transition in the azo group of 3,3'-abpy.
The electronic spectra of 1-5 show intense bands in the UV region at 318 nm (ε  20000 Lmol-
1
-1
cm ), arising from π-π* transitions of 3,3'-abpy. Lower energy and weaker bands for the
-1
-1
complexes were observed at about 442 nm (ε  700 Lmol cm ). For the octahedral Ni(II)
3
3
3
3
complex (1), the expected three bands which are assigned to A → T (ѵ ), A → T (F) (ѵ )
2
g
2g
1
2g
1g
3
3
3
and A → T (P) (ѵ ) d-d transition are not observed. A third band in [Cu(sac) (H O)(µ-3,3'-
2
g
1g
3
2
2
abpy)] at 800 nm is assumed to be associated with a →b (d →d 2) transition.
n
1
1
2
2
x –y
z
The photoluminescence spectra of 3-5 and free 3,3ʹ-abpy were recorded at room
temperature in the solid state. The 3,3ʹ-abpy displays photoluminescence with the emission
maximum at 551 nm accompanied by shoulder peaks at 579 and 590 nm upon excitation at 384
nm. The emission band of 3,3ʹ-abpy is attributed to π*n and π*π transitions. As depicted in
figure 12, emission bands are observed at 550, 577 and 591 nm for 3; 547, 578 and 590 nm for 4;
5
49, 579 and 590 nm for 5 upon excitation at 384 nm, respectively. The photoluminescence
spectra of 3-5 and free 3,3′-abpy are similar. It is suggested that the photoluminescent properties
of 3-5 may be attributed to intraligand transition of coordinated 3,3’-abpy ligand [38, 39].
Thermal decomposition behavior of the complexes was studied under static air from
3
0-1000 °C. (The thermal analysis curves of 1-5 are given in figures S2-S5).
The TGA analyses of 1 reveal weight loss at 122-190 °C, which corresponds to loss of
water molecules in one step (a single peak on the DTG curve and endothermic DTA peak at
59 °C (exp. 8.61; calc. 8.34%). This is consistent with the existence of a single structural type
1
of water molecules in the structure. The second stage for the anhydrous complex is related to
decomposition of 3,3'-abpy ligands in several overlapping steps from 221-319 °C. The following
9

exothermic stages between 319–532 °C (DTAmax = 450, 472 and 485 °C) are related to
decomposition of the sac and burning of organic residue. The final decomposition product is NiO
(found 91.65%, calc. 91.31%).
The thermal dehydration of 2 occurs first by giving an endothermic peak at 173 °C. The
weight loss (exp. 2.98; calc. 2.87%) at 140-186 °C corresponds to loss of one coordinated water
molecule. After 227 °C, anhydrous Cu(II) complex loses azobispyridine ligand and SO from the
2
saccharinato ions within several overlapping steps. The remaining saccharinato residue burns
vigorously in the last stage, accompanied with a strong exothermic peak (about 512 °C) until it
gives CuO (exp. 88.21; calc. 87.30%).
In the first stage of 3, endothermic removal of water molecules in two steps (two DTG
peaks at 103 and 115 °C; figure S4) occurs at 114-122 °C (exp. 8.51; calc. 8.47%). The TG
curves of anhydrous Zn(II) complex have mass loss from 135-234 °C, attributed to endothermic
(DTAmax = 208 °C) loss of 3,3′-abpy ligand (exp. 20.35, calc. 21.16%). In several consecutive
stages, the residue loses the rest of the abpy ligand and SO from the saccharinato ions at 275-
2
5
49 °C (exp. 36.74, calc. 35.89%). In the last stage, a strong exothermic peak on the DTA curve
(DTAmax = 596 °C) is associated with burning of the organic residue, leading to ZnO and the
overall mass loss is exp. 91.08, calc. 90.69%.
In 4, similar to 1-3, the first process, 124-189 °C, corresponds to loss of two aqua ligands
in a single step (exp. 5.18, calc. 5.17%). In the second step, endothermic (DTAmax = 326 °C)
mass loss is attributed to loss of 3,3′-abpy (exp. 23.83, calc. 26.43%). The following stage
between 360 and 510 °C is due to decomposition of sac (DTAmax = 403 °C). During the last
stage, the remaining organic part is abruptly burnt exothermically (DTAmax.= 512 °C). The
overall weight loss is exp. 81.58, calc. 81.58% refers to the final decomposition product is CdO.
Complex 5 is stable to 198 °C and undergoes decomposition in four stages. The weight
loss (exp. 26.90; calc. 29.51%) at 198-256 °C corresponds to loss of two 3,3′-abpy and SO from
2
the saccharinate. The endothermic second and third stages are due to decomposition of the sac
(DTAmax = 238 °C; 287 °C). Complexes 1-4 decompose exothermically at higher temperatures to
give the corresponding metal oxides, although the Hg(II) complex sublimes at 550 °C and
volatilizes completely.
8
The room temperature magnetic moment of 1 of 2.84 BM is suitable for the d octahedral
configuration (calc. 2.83 BM). Effective magnetic moment of 2 is 1.81 BM at room temperature.
1
0

9
The experimental value is very close to the value of 1.73 BM expected for a d Cu(II) ion. As
1
0
expected, the d metal complexes (3-5) are diamagnetic.
4
. Conclusion
In this study, five new complexes with 3,3′-abpy and sac were synthesized and structurally
characterized. In the complexes, sac has three different forms, as counter ion (1 and 3),
N-coordinated (2, 4 and 5), and both N- and O-coordinated (5). The 3,3'-abpy is monodentate
(1 and 3), bridging (2 and 4) and both monodentate and bridging (5) (scheme 1). Complexes 1
and 3 are mononuclear while 2, 4 and 5 were 1D coordination polymers. The photoluminescence
spectra of 3-5 show that the photoluminescent properties of complexes may be attributed to
intraligand transition of coordinated 3,3’-abpy ligand. Thermal decomposition of 1-5 take place
from 20-1000 °C in static air.
Acknowledgement
We thank Dr. Wolfgang Frey for crystallographic data collection. CCDC 1471164, 1471163 and
1
050467–1050469 contain the supplementary crystallographic data for 1-5, respectively. 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.
References
[1]
[2]
[3]
E.J. Baran. Quim. Nova, 28, 326 (2005).
E.J. Baran, V.T. Yılmaz. Coord. Chem. Rev., 250, 1980 (2006).
İ İlker, O.Z. Yeşilel, G. Günay, O. Büyükgüngör. J. Organomet. Chem., 694, 4178
(
2009).
C.A. Johns, G.M.G. Hossain, K.M.A. Malik, S.Z. Haider, U.K.R. Romman. Polyhedron,
0, 721 (2001).
[4]
2
[5]
[6]
[7]
[8]
R. Bıyık, R. Tapramaz, O.Z. Yeşilel. Spectrochim. Acta, Part A, 68, 394 (2007).
E. Güney, V.T. Yılmaz, C. Kazak. Polyhedron, 29, 1285 (2010).
I. Uçar, E. Bozkurt, C. Kazak, A. Bulut. Spectrochim. Acta, Part A, 72, 11 (2009).
L.S. Kelso, D.A. Reitsma, F.R. Keene. Inorg. Chem., 35, 5144 (1996).
1
1

[
[
[
[
[
[
[
9]
Y. Li, Z.-Y. Lin, W.-T. Wong. Eur. J. Inorg. Chem., 3163 (2001).
10] D.A. Baldwin, A.B.P. Lever, R.V. Parish. Inorg. Chem., 8, 107 (1969).
11] B. Li, H. Liu, Y. Xu, J. Chen, H. Wang, Z. Xu. J. Mol. Struct., 597, 21 (2001).
12] R. Dey, D. Ghoshal. Polyhedron, 34, 24 (2012).
13] O. Theilmann, W. Saak, D. Haase, R. Beckhaus. Organometallics, 28, 2799 (2009).
14] F. Arslan. Dyes Pigm., 75, 521 (2007).
15] Z. Zhuang, J. Cheng, X. Wang, Y. Yin, G. Chen, B. Zhao, H. Zhang, G. Zhang. J. Mol.
Struct., 794, 77 (2006).
[
16] S. Noro, S. Kitagawa, T. Nakamura, T. Wada. Inorg. Chem., 44, 3960 (2005).
17] Z. Zhuang, X. Shang, X. Wang, W. Ruan, B. Zhao. Spectrochim. Acta, Part A, 72, 954
[
(2009).
[18] Y. Niu, Y. Song, H. Hou, Y. Zhu. Inorg. Chim. Acta, 355, 151 (2003).
[19] J. Launay, M. Tourrel-Pagis, J. Lipskier, V. Marvaud, C. Joachim. Inorg. Chem., 30,
1
033 (1991).
[
[
[
20] S.M. Abdallah. Arabian J. Chem., 5, 251 (2012).
21] E. Kucharska, J. Hanuza, A. Waskowska, Z. Talik. Chem. Phys., 306, 71 (2004).
22] M. Odabaşoğlu, Ç Albayrak, R. Özkanca, F.Z. Aykan, P. Lonecke. J. Mol. Struct., 840,
7
1 (2007).
23] A. Wasilewska, M.J. Milewska, M. Gdaniec, .T. Połonski. Tetrahedron: Asymmetry, 20,
472 (2009).
[
1
[24] D. Oyama, R. Fujita, S. Yui. Inorg. Chem. Commun., 11, 310 (2008).
[25] E. Corral, A.C.G. Hotze, D.M.A. Tooke, L. Spek, J. Reedijk. Inorg. Chim. Acta, 359, 830
(2006).
[
26] A. Dogan, B. Sarkar, A. Klein, F. Lissner, T. Schleid, J. Fiedler, S. Zalis, V.K. Jain, W.
Kaim. Inorg. Chem., 43, 5973 (2004).
[
27] (a) G.M. Sheldrick, SHELX97, Programs for Crystal Structure Analysis (release 97–1),
University of Göttingen, Germany (1997). (b) G.M. Sheldrick, SHELXL97, Program for
the Refinement of Crystal Structures, University of Göttingen, Germany (1997).
28] S.Z. Haider, K.M.A. Malik, K.J. Ahmed. J. Bangladesh Acad. Sci., 5, 81 (1981).
29] S.Z. Haider, K.M.A. Malik, K.J. Ahmed. Inorg. Synth., 23, 47 (1985).
30] S.A. Al-Jibori, Z.S. Afandi, K. Merzweiler, C. Wagner, H. Schmidt, S. Basak-Modi, G.
[
[
[
1
2

Hogarth. Polyhedron, 81, 442 (2014).
[31] E.J. Baran, V.T. Yilmaz. Coord Chem. Rev., 250, 1980 (2006).
[32] P. Naumov, G. Jovanovski. J. Mol. Struct., 563-564, 335 (2001).
[33] V.T. Yılmaz, S. Guney, C. Kazak. Polyhedron, 27, 1381 (2008).
[34] O.Z. Yeşilel, C. Darcan, E. Şahin. Polyhedron, 27, 905 (2008).
[35] A.W. Addison, T.N. Rao. J. Chem. Soc., Dalton Trans., 1, 1349 (1984).
[36] P.A.M. Williams, E.G. Ferrer, M.J. Correa, E.J. Baran, E.E. Castellano, O.E. Piro.
J. Chem. Crystallogr., 34, 285 (2004).
[
[
[
37] L. Jianmink, K. Yanxıong, W. Quanming, W. Xintao. Cryst. Res. Technol., 32, 481
(1997).
38] W.-F. Fu, X. Gan, J. Jiao, Y. Chen, M. Yuan, S.-M. Chi, M.-M. Yu, S.-X. Xiong. Inorg.
Chim. Acta, 360, 2758 (2007).
39] M. Déniz, J. Pasán, O. Fabelo, L. Cañadillas-Delgado, P. Lorenzo-Luis, F. Lahoz, D.
López, C. Yuste, M. Julve, C. Ruiz-Pérez. C. R. Chimie, 15, 911 (2012).
1
3

Figure 1. The crystal structure of 1 showing the atom numbering scheme.
1
4

(a)
(b)
Figure 2. (a) Hydrogen-bonding, O-H and C-H interactions (hydrogens not involved in
hydrogen bonds were omitted for clarity). (b) The  interactions for 1 ((i) –x, -y, -z; (ii) -x, -y,
-1-z; (iii) x, y, 1+z).
1
5

(a)
(b)
Figure 3. (a) The molecular structure of 2 showing the atom numbering scheme. (b) View of the
infinite 1D chain structure of 2.
1
6

Figure 4. Intermolecular O-H···O hydrogen-bonding interactions between 1D chains in 2.
1
7

Figure 5. The crystal structure of 3 showing the atom numbering scheme.
1
8

(a)
(b)
Figure 6. (a) Intermolecular O-H···N hydrogen-bonding and π···π interactions. (b) O-H···O
hydrogen-bonding interactions between adjacent 1D chains. (Hydrogens not involved in
hydrogen bonds were omitted for clarity.) ((i) -1-x, -y, -z; (ii) -1+x, y, -1+z; (iii) -x, -y, 1-z).
1
9

(a)
(b)
(c)
Figure 7. (a) An infinite 1D chain. (b) View of the unit cell in 4. (c) Intermolecular O-H···O
hydrogen-bonding interactions between 1D chains (hydrogens not involved in hydrogen bonds
were omitted for clarity).
2
0

Figure 8. The crystal structure of 4 showing the atom numbering scheme ((i) -1-x, 1-y, 1-z; (ii)
x, -y, 1-z).
-
2
1

Figure 9. The crystal structure of 5 showing the atom numbering scheme.
2
2

Figure 10. View of the infinite 1D chain structure and S=O interactions of 5.
2
3

Figure 11. The  interactions for 5.
2
4

Figure 12. The photoluminescence spectra of 3-5 and free 3,3ʹ-abpy.
2
5

Table 1. Crystal data and structure refinement parameters for 1-5.
Crystal data
1
2
3
4
5
Empirical
formula
C H N O
S2Ni
C H N O S C C H N O S Z C H N O S C C H N O S H
24 18 6 7 2 34 32 10 10 2 24 20 6 8 2 29 20 8 6 2
3
4
32 10 10
u
n
d
g
Formula
weight
8
63.53
630.11
870.19
696.99
841.24
Crystal system Monoclinic
Monoclinic
100(2)
0.71073
C2/c
Monoclinic
100(2)
Monoclinic
100(2)
Monoclinic
100(2)
T (K)
100(2)
λ (Å)
0.71073
P21/n
0.71073
P21/n
0.71073
P21/n
0.71073
C2/c
Space group
a (Å)
7.6897(5)
19.8637(12)
12.1449(7)
94.802(3)
1848.6(2)
2
23.109(5)
13.077(3)
18.842(4)
114.05(3)
5200(2)
1
7.7061(15)
19.928(4)
13.898(4)
118.90(2)
1868.5(7)
2
7.5749(5)
9.5633(6)
19.4468(11)
101.01(2)
1382.8(2)
2
19.7968(10)
22.3570(11)
14.5856(7)
114.500(2)
5874.3(5)
8
b (Å)
c (Å)

()
V (Å3)
Z
–
3
D (g cm )
1.551
1.605
1.547
1.674
1.902
c
–
1
μ (mm )
0.71
1.06
0.84
1.00
5.44
Measured ref. 21185
5370
21654
15798
32159
Independent
ref.
5
654
5370
5687
4241
8891

Range (º)
2.0–30.6
1.8–26.5
2.0–30.5
2.1–30.6
1.5–30.5
Crystal size
0.47 × 0.40 × 0.24 × 0.13 ×
0.53×0.49×0.3
0
0
.46×0.22×0.19
0.52×0.12×0.09
(mm)
0.31
0.07
0.000
1.06
Rint
S
0.029
0.966
0.040
1.07
0.025
1.11
0.059
0.98
R,
0
.043, 0.079 0.073, 0.122
.51/−0.39 1.53/−1.03
0.066, 0.182
0.025, 0.056
0.035, 0.063
Rw[I>2(I)]


/min
max
0
2.64/−2.24
0.42/−0.70
1.56/−1.32
–
3
(
eÅ )
2
6

Table 2. Selected bond distances and angles for 1-5 (Å, ).
Complex 1
Ni1‒O1
2.0621(10)
2.0646(10)
87.87(4)
Ni1‒N‒1
N3‒N4
2.1008(11)
1.2549(17)
92.99(4)
Ni1‒O‒2
O2‒Ni1‒N1
Complex 2
Cu2‒O1
O1‒Ni1‒N1
2.161(5)
2.048(4)
96.76(11)
Cu2‒N2
2.005(4)
Cu2‒N1
N2‒Cu2‒O1
94.95(11)
N1‒Cu2‒O1
Complex 3
Zn1−O1
1.979(2)
1.983(2)
101.39(8)
96.10(9)
Zn1−N1
2.556(3)
76.40(9)
Zn1−O2
O1−Zn1−O2
O1−Zn1−N1
Complex 4
Cd1−N3
O2−Zn1−N1
2.3208(13)
2.3433(11)
94.66(4)
Cd1−N1
2.3477(13)
86.63(4)
Cd1−O1
N3−Cd1−O1
N3−Cd1−N1
Complex 5
Hg1−N7
O1−Cd1−N1
89.96(5)
2.174(3)
Hg1−N1
Hg1−N5
2.280(3)
2.485(3)
Hg1−N8
2.188(3)
i
Hg1 −O4
2.672(3)
N7−Hg1−N8
N7−Hg1−N1
123.62(11)
125.27(10)
N8−Hg1−N1
N7−Hg1−N5
110.65(11)
93.52(10)
2
7

Table 3. Hydrogen-bond parameters for 1-4 (Å, ).
D-H···A
D−H
H···A
D···A
D−H···A
Complex 1
O1-H1A…O21
O1-H1B…O22
O2-H2A…N5
O2-H2B…O21
Complex 2
0.81
0.80
0.81
0.79
1.99
1.88
1.91
2.23
2.7948
2.6750
2.7137
2.9732
177
174
171
159
C1A-H1AB…O22B
C5A-H5AA…O1A
C5-H5A…O1
Complex 3
0.95
0.95
0.95
2.57
2.56
2.55
3.3008
3.1851
3.1725
134
123
124
O1−H1B···O5
O1−H1A···O4i
O2−H2B···N4ii
C14−H14···N5iii
Complex 4
0.86
0.86
0.86
0.93
1.86
1.99
1.94
2.16
2.596 (3)
2.757 (3)
2.678 (3)
2.833 (4)
141
148
144
128
O1−H1A···O22
O1−H1B···O22
0.81
0.88
2.16
1.83
2.8080
2.6808
137
163
Symmetry codes: (i) x+1, y, z; (ii) x, y, z+1; (iii) x-1/2, -y-1/2, z-1/2 for 3 and (i) -1+x,
y, z; (ii)1-x, 1-y, 1-z for 4.
2
8

2
9