Syntheses, structures, thermal behavior and solution studies of two types of Hg(II) complexes with [1,3-di(2-methoxy)benzene]triazene

Article abstract of DOI:10.1016/j.ica.2009.04.041

The reaction of [1,3-di(2-methoxy)benzene]triazene, [HL], with Hg(CH₃COO)₂ and Hg(SCN)₂ in methanol as solvent, resulted in the formation of [HgL₂] (1) and [HgL(SCN)] (2), respectively. These compounds were char

Full text of DOI:10.1016/j.ica.2009.04.041

Inorganica Chimica Acta 362 (2009) 3777–3784
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Syntheses, structures, thermal behavior and solution studies of two types
of Hg(II) complexes with [1,3-di(2-methoxy)benzene]triazene
*
Mohammad K. Rofouei , Marjan Hematyar, Vanik Ghoulipour, Jafar Attar Gharamaleki
Faculty of Chemistry, Tarbiat Moallem University, 49 Mofateh Ave., Tehran, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
The reaction of [1,3-di(2-methoxy)benzene]triazene, [HL], with Hg(CH3COO)2 and Hg(SCN)2 in methanol
as solvent, resulted in the formation of [HgL2] (1) and [HgL(SCN)] (2), respectively. These compounds
were characterized by means of X-ray diffraction, FT-IR spectroscopy, CHN and TGA–DTA analysis. In
the lattice of the compound 1, the mono-nuclear complexes were connected to dimer structure by inter-
Received 12 November 2008
Accepted 24 April 2009
Available online 7 May 2009
molecular non-classical C–HÁÁÁO hydrogen bonds. Also, weak Hg-
into 1D supramolecular chains. The compound 2 is a 2D coordination polymer induced by C–HÁÁÁ
ing interactions between 1D chains produced by weak Hg-g3 3-arene
-interactions. The results of
g
2-arene
p
-interactions link the dimers
Keywords:
Mercury(II)
Triazene
Crystal structure
Solution studies
p
stack-
-g
p
studies of the stoichiometry and formation of complexes of 1 and 2 in methanol solution were found
to be in support of their solid state stoichiometry.
Ó 2009 Elsevier B.V. All rights reserved.
C–HÁÁÁ
p
stacking interactions
-interactions
Hg- -arene
g
p
1. Introduction
by Popovic et al. [21,22]. On the other hand, triazenes and anionic
triazenide ligands could show different types of coordination in me-
In recent years, the self-assembled metal–organic complexes
have attracted intense attention because of their fascinating
molecular structures and crystal-packing motif [1–3], along with
their potential application in the area of functional materials
[4,5]. Aside from the fundamental and strong metal–ligand coordi-
nation covalent bond, other relatively weak intermolecular inter-
tal complexes like monodentate, (N1,N3)-chelating towards one
metal atom or (N1,N3)-bridging over two metal atoms [23].
We have previously reported the synthesis of Ag(I) complex with
[1,3-di(2-methoxy)benzene]triazene, [HL], as ligand [24,25]. Also,
we have published the Hg(II) complexes with this ligand by using
HgCl2 and HgBr2 as starting materials [26,27]. From recent struc-
tural studies, it has been argued that counter-anions play an impor-
tant role in determining the solid state lattices of such compounds.
Continuing with our previous works, here we report the syntheses,
characterization and molecular structure of two new Hg(II) coordi-
nation polymers obtained from the mentioned ligand with
Hg(CH3COO)2 and Hg(SCN)2 in methanol as solvent. Scheme 1 pre-
sents the procedure of the applied reactions and starting materials.
actions such as hydrogen-bonding and
p–p stacking interactions
are also useful tools in assembling such supramolecular complexes
[6–8]. In this regard, the organic ligands play an important role in
adjusting the architectures of their metal complexes, so proper
selection of ligands is the key issue in construction of supramolec-
ular networks [9–11]. However, the crystal engineering with de-
sired topologies and specific properties still remains a difficult
challenge since there are a variety of factors influencing the self-
assembly process such as the coordination geometry and the oxi-
dation state of the metal ions [12–14], metal-to-ligand ratio [15],
nature of the ligands [16], solvents [17] and/or counter-anions
[18], even the reaction temperature and pH value [19,20].
2. Experimental
2.1. Materials and physical techniques
Hg(II) is a diamagnetic ion and maintains d10 electron configura-
tion which minimizes intrinsic coordination geometry preferences
while favoring coordination by softer ligands. Thus, mercury(II) is
capable of forming various binding coordination modes when do-
nor atoms provided by suitable ligands [21]. The tendency of mer-
cury to achieve effective coordination by spatial arrangement of
donor atoms of different types of counterions has been reported
All chemicals were of analytical grade and were used as com-
mercially obtained without further purification. IR spectra were re-
corded using Perkin–Elmer RXI spectrometer using KBr disks.
Elemental analysis was carried out using a Perkin–Elmer 2400(II)
CHNS/O analyzer. Melting points were measured on a Barnstead
Electrothermal 9200 apparatus. UV–Vis spectra were recorded
with a Perkin–Elmer Lambda 25 spectrophotometer, using two
matched 10-mm quartz cells. TGA–DTA were carried out with a
Rheometric Scientific 1500 at a heating rate of 10 °C/min in air.
Crystallographic measurements were made at 296(2) K using a
* Corresponding author. Tel.: +98 21 88848949; fax: +98 21 88820993.
E-mail address: rofouei@tmu.ac.ir (M.K. Rofouei).
0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2009.04.041

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M.K. Rofouei et al. / Inorganica Chimica Acta 362 (2009) 3777–3784
H3C
O
CH3
O
N
N
Hg
N
N
N
(1)
N
Hg(CH COO)
1/2
3
2
O
O
CH3
CH3
H3C
O
O
H3C
H
N
N
N
1
CH3
O
N
1Hg(SCN)2
N
(2)
Hg
S
C
N
N
O
CH3
Scheme 1.
Bruker APEX2 CCD area detector diffractometer. The intensity data
were collected within the range 2.42–28.00 using graphite mono-
chromated Mo Ka radiation (k = 0.71073 Å). The structure has been
solved by direct methods and refined by full-matrix least-squares
techniques on F2 using SHELXTL [28]. The molecular structure plots
were prepared using ORTEP [29] and mercury [30].
anhydrous methanol were added. After 1/2 h stirring, an orange
precipitate was formed. It was then filtered off, washed with meth-
anol and dried in vacuum. The solid was dissolved in 20 ml pure
diethyl ether (stored in a freezer). Orange-red plate like crystals
suitable for X-ray analysis of the complex is obtained by slow
evaporation of the solvent in a week.
Properties: air stable, orange-red crystalline material.
C28H28HgN6O4 (713.15); Yield: 0.153 g (0.214 mmol), 21.4% based
on mercury (II) acetate, m.p.: 146–148 °C.
2.2. Synthesis of [HgII (RPhNNNPhR)2] (R = OCH3) (1)
To a yellow solution prepared by dissolving 0.514 g (2 mmol) of
[1,3-di(2-methoxy)benzene]triazene in 20 ml of anhydrous metha-
nol, 0.319 g (1 mmol) of mercury(II) acetate dissolved in 20 ml of
IR (KBr) free ligand [HL]: 3159.36 (s, m(N–H)), 1027.42 (s, m(O–
C)), 1422.65 (s, m ms(N–N)). The complex
(N@N)), 1179.31 cmÀ1 (s,
[HgII(RPhNNNPhR)2]: the N–H band is suppressed; 1022.98 (s,
m
Table 1
Crystal data and structure refinement parameters for complexes 1 and 2.
(1)
(2)
Empirical formula
Formula weight
Temperature
C28H28HgN6O4
713.15
296 (2) K
0.71073
C15H14HgN4O2S
514.95
100 (2) K
0.71073
Wavelength
Crystal system
Space group
orthorhombic
Pbca
triclinic
P1
ꢀ
Unit cell dimensions
a = 8.1566 (6) Å
a = 10.5275 (6) Å;
a = 96.5400 (10)°
b = 19.4194 (15) Å
b = 11.0219 (6) Å; b = 100.0810 (10)°
c = 33.770 (3) Å
5349.0 (7)
c = 14.9088 (9) Å; c = 104.6510 (10)°
1624.95 (16)
Volume (Å3)
Z
8
4
Density (calculated) (Mg/m3)
Absorption coefficient (mmÀ1
F(0 0 0)
1.771
5.80
2800
2.105
9.61
976
)
Crystal size (mm)
h range for data collection
Index ranges
0.38 Â 0.25 Â 0.20
0.22 Â 0.03 Â 0.03
2.42–28.00
2.58–25.43
À10 6 h 6 10, À25 6 k 6 25, À44 6 l 6 44
À12 6 h 6 12, À13 6 k 6 13, À18 6 l 6 18
Reflections collected
63 951
25 997
Independent reflections [Rint
]
6406
6301
Absorption corrections
Maximum and minimum transmission
Refinement method
multi-scans
0.1906 and 0.312
full-matrix-least-squares on F2
6406/0/352
1.010
multi-scans
0.706 and 0.755
full-matrix-least-squares on F2
6301/0/415
1.023
Data/restraints/parameters
Goodness-of-fit (GOF) on F2
Final R[I > 2
r(I)]
0.040
1.911 and À0.891
0.057
2.688 and À1.177
Largest differences in peak and hole (e ÅÀ3
)

M.K. Rofouei et al. / Inorganica Chimica Acta 362 (2009) 3777–3784
3779
Table 2
Selected bond and length (Å) and angles (°) for complexes 1 and 2.
(1)
Hg1–N1
Hg1–N6
Hg1–N3
2.089 (4)
2.092 (4)
2.646 (4)
Hg1–N4
Hg1–O4
Hg1–O1
2.692 (4)
2.720 (4)
2.786 (4)
N1–Hg1–N6
N1–Hg1–N3
N6–Hg1–N3
N1–Hg1–N4
N6–Hg1–N4
N3–Hg1–N4
N1–Hg1–O4
N6–Hg1–O4
174.39 (16)
51.74 (15)
133.87 (15)
124.43 (15)
51.43 (15)
145.17 (13)
118.75 (14)
65.51 (14)
N3–Hg1–O4
N4–Hg1–O4
N1–Hg1–O1
N6–Hg1–O1
N3–Hg1–O1
N4–Hg1–O1
O4–Hg1–O1
78.52 (12)
116.82 (12)
64.91 (14)
109.52 (13)
116.49 (12)
74.96 (12)
136.92 (12)
(2)
Hg1–N1
Hg1–S1
Hg1–N3
2.112 (8)
2.344 (3)
2.528 (10)
Hg2–N4
Hg2–S2
Hg2–N6
2.101 (9)
2.337 (3)
2.565 (10)
N1–Hg1–S1
N1–Hg1–N3
S1–Hg1–N3
174.5 (3)
53.6 (3)
130.4 (2)
N4–Hg2–S2
N4–Hg2–N6
S2–Hg2–N6
172.2 (3)
53.2 (3)
131.6 (2)
(O–C)), 1277.07 cmÀ1 (s,
the N–N absorptions in the free ligand (average bond order). Ele-
mental Anal. Calc. for C28H28HgN6O4: C, 47.15; H, 3.92; N, 11.77.
Found: C, 47.13; H, 3.69; N, 11.72%.
m
s(NNN)), a mean value with respect to
is consistent with the presence of S-terminal thiocyanato ions [31]
which is in agreement with the X-ray diffraction studies. Elemental
Anal. Calc. for C15H14HgN4O2S: C, 34.98; H, 2.71; N, 10.87. Found: C,
35.55; H, 2.69; N, 10.76%.
2.3. Synthesis of [HgII (RPhNNNPhR)SCN] (R = OCH3) (2)
3. Results and discussion
This complex was also synthesized by the above mentioned
method, except in it 0.257 g (1 mmol) of [1,3-di(2-methoxy)ben-
zene]triazene in 20 ml of anhydrous methanol, 0.317 g (1 mmol)
of mercury(II) thiosyanate dissolved in 20 ml of anhydrous metha-
nol were used and the resultant precipitate after filteration and
washing was dissolved in THF. Orange-red needle like crystals suit-
able for X-ray analysis of the complex 2 are obtained by slow evap-
oration of the solvent in a week.
Crystal data and experimental conditions for complexes 1 and 2
are given in Table 1. Selected bond distances and angles of them
are listed in Table 2.
3.1. Structure descriptions
The molecular structure of the [HgII (RPhNNNPhR)2] (R = OCH3)
(1), is presented in Fig. 1. Thermal ellipsoid are drawn at 50% prob-
ability level. The Hg(II) atom is coordinated by two symmetrically
independent triazenide ions. Each triazendie ion is coordinated to
central atom through two N atoms [Hg1–N1 = 2.089(4) Å and
Hg1–N3 = 2.646(4) Å] for one ligand, and [Hg1–N4 = 2.692(4) Å
and Hg1–N6 = 2.092(4) Å] for the other one, and one O atom
[Hg1–O1 = 2.786(4) Å, and Hg1–O4 = 2.720(4) Å] which are rela-
Properties: air stable, orange-red crystalline material.
C15H14HgN4O2S (514.95); Yield: 0.273 g (0.53 mmol), 53% based
on mercury (II) thiocyanate, d.p.: 157–159 °C. IR (KBr) The complex
[HgII(RPhNNNPhR)SCN]: the N–H band is suppressed. 1020.91 (s,
m
(O–C)), 1281.80 cmÀ1 (s,
m
s(NNN)), a mean value with respect to
the N–N absorptions in the free ligand (average bond order). Also,
the appearance of strange
as(S–C„N) absorption at 2139.27 cmÀ1
m
Fig. 1. ORTEP diagram of the structural unit of 1 with the atomic numbering scheme. Thermal ellipsoids are drawn at 50% probability level.

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Fig. 2. (a) View of the 1D supramolecular network formed by non-classical C–HÁÁÁO hydrogen bonding (the red dashed line), and Hg-
g p-interactions (the black
2-arene
dashed line) in 1; (b) space filling representation, close approaches of Hg(II) to the face of phenyl rings can be seen (Hg = pink, O = red, C = gray, N = blue). Hydrogen atoms are
omitted for clarity. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

M.K. Rofouei et al. / Inorganica Chimica Acta 362 (2009) 3777–3784
3781
Fig. 3. ORTEP diagram of the structural unit of 2 with the atomic numbering scheme. Thermal ellipsoids are drawn at 50% probability level.
tively weaker interaction. Hg–O and Hg–N bonds with longer dis-
tance have been reported in the literature [32,33].
In the lattice of the compound 1 (see Fig. 2), the monomeric
[Hg(RPhNNNPhR)2] moieties are linked to pairs through non-
Consequently, 1D chains formed by metal-
connected with one another by C–HÁÁÁ stacking interactions,
resulting in the 2D architecture. These C–HÁÁÁ stacking interac-
tions are present between CH groups with aromatic rings with
p interactions are
p
p
classical C–HÁÁÁO hydrogen bonds (C11ÁÁÁO3 = 3.488(7)
Å
and
HÁÁÁ
p
distances of 2.78 Å for C24ÀH24AÁÁÁCg1 (2 À x, Ày, Àz), 2.90
<C11–H11AÁÁÁO3 = 168°, symmetry code (2 À x, Ày, Àz) [34,35].
The resulted dimeric units are assembled by translation along
the crystallographic a-axis to unidimensional chains linked
Å
for C114ÀH11GÁÁÁCg2 (x, À1 + y, z) and 2.97
Å
for
C210ÀH21AÁÁÁCg3 (2 À x, 1 À y, 1 À z) [Cg1, Cg2 and Cg3 are the
centroids for C18–C113, C28–C213 and C11–C16 rings, respec-
tively] [40].
through secondary Hg-
g
2-arene
p-interactions involving two car-
bon atoms of the C15–C20 phenyl ring. These metal-
p
interactions
involve the Hg1 atom and C17 [3.412(5) Å], and C18 [3.419(5) Å]
atoms with related symmetry code (1 + x, y, z). The reported HgÁÁÁC
separations range is 3.15–3.74 Å in recent reported similar Hg-tria-
zenide complexes [36–39].
3.2. Thermal analysis
To examine the thermal stability of the two new compounds,
thermal gravimetric (TGA) and differential thermal analyses
(DTA) were carried out in air (Figs. 5 and 6). As evident from the
TGA–DTA curves of the complex 1, at normal temperature and
pressure the crystals possess good stability and an endothermic
thermal event occur in the sample due to melting at about
150 °C. Also, The TGA curve of 1 (Fig. 5) shows a large weight loss
of 71.52%, (Calc.: 69.63%) in the range 180–300 °C followed by an
exothermic DTA peak with a maximum at about 216 °C that could
be related to the formation of HgO. TGA curve subsequently con-
tinues with a weight loss in range up to 800 °C with one exother-
mic and one endothermic peaks in the DTA curve.
The TGA–DTA curves of compound 2 are shown in Fig. 6. This
compound does not melt and is stable up to 150 °C. TGA curve indi-
cates the decomposition of compound 2 takes place above 150 °C,
which is corresponding to the presence of an exothermic peak at
this temperature. As it can be seen from the TGA curve, this com-
pound subsequently weight loss up to 610 °C in several steps that
followed by a broad exothermic peak.
The molecular structure of the [HgII (RPhNNNPhR)SCN]
(R = OCH3) (2), is presented in Fig. 3. Thermal ellipsoid are drawn
at 50% probability level. There are two independent complexes of
Hg(II) with slightly different bond distances and angles. In one
fragment, i.e. [Hg1], the Hg atom is planar and is coordinated by
one triazenide ion through two N atoms [Hg1–N1 = 2.112(8) and
Hg(1)–N3 = 2.528(10)] and one O atom [Hg1–O1 = 2.829(9)] which
is relatively weaker interaction. Moreover, the Hg(II) is coordinated
by one thiocyanate ion through S atom [Hg1–S1 = 2.344(3) Å]. In
Hg2 fragment, the Hg2–N4, Hg2–N6, Hg2–O3 and Hg2–S2 bond
distances are 2.101(9), 2.565(10), 2.768(9) and 2.337(3),
respectively.
In the lattice of this compound (Fig. 4), the molecules contain-
ing Hg1 and Hg2 are stacked along the crystallographic a-axis to
form infinite chains. Within the chains, each Hg(II) ion is addition-
ally coordinated by two peripheral phenyl rings of two neighboring
complexes by secondary weak metal-g3 g3 interactions. The two
-
phenyl rings are located parallel to the main molecular plane.
These metal- interactions involve the Hg1 atom and C14
p
3.3. Solution studies
[3.300(13) Å], C15 [3.090(12) Å] and C16 [3.523(13) Å] atoms with
related symmetry code (3 À x, Ày, 1 À z) as well as, C110
[3.452(13) Å], C111 [3.337(13) Å] and C112 [3.505(14) Å ] with
symmetry code (2 À x, Ày, 1 À z). Furthermore, Hg2 atoms have
In a typical procedure, 2.0 ml of ligand solution (5.0 Â 10À5 M) in
MeOH was placed in the spectrophotometer cell and the absorbance
of the solution was measured. Then a known amount of the concen-
trated solution of mercury(II) acetate or thiocyanate in MeOH
weak intermolecular metal-
p interactions with C24 [3.296(14)
Å], C25 [3.131(12) Å], and C26 [3.538(12) Å] (2 À x, 1 À y, Àz) as
well as, C210 [3.475(13) Å], C211 [3.463(13) Å] and C212
[3.652(13) Å] (1 À x, 1 À y, Àz).
(5.0 Â 10À3 M) was added in a stepwise manner using a 5-
ll Ham-
ilton syringe. The absorbance spectrum of the solution was recorded
after each addition. The mercury(II) acetate or thiocyanate solution

3782
M.K. Rofouei et al. / Inorganica Chimica Acta 362 (2009) 3777–3784
Fig. 4. (a) View of the 2D supramolecular network formed by C–HÁÁÁp -g p-interactions (the black dashed line)
stacking interactions (the red dashed line), and Hg-g3 3-arene
in 2; (b) space filling representation, close approaches of Hg(II) to the face of phenyl rings can be seen (Hg = pink, O = red, C = gray, N = blue, S = yellow). Hydrogen atoms are
omitted for clarity. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
was continually added until the desired metal to ligand mole ratio
was achieved. The electronic absorption spectra of the ligand in
the presence of increasing concentration of mercury(II) acetate or
thiocyanate in MeOH at room temperature are shown in Figs. 7
and 8, respectively. The resulting absorbance (at 400 nm) against
[Hg2+]/[HL] mole ratio plot, shown in the inset of Fig. 7, reveals dis-
tinct inflection points at a metal-to-ligand molar ratio of about 0.5
and 1 emphasizing the formation of a 1:2 and 1:1 complexes. And
the resulting absorbance (at 373 nm) against [Hg2+]/[HL] mole ratio
plot, shown in the inset of Fig. 8 reveals distinct inflection points at a
metal-to-ligand molar ratio of about 1 emphasizing the formation of
a 1:1 complex in MeOH solution. For evaluation of the conditional
formation constants, the mole ratio data obtained by the physico-
chemical method employed were fitted to the previously reported

M.K. Rofouei et al. / Inorganica Chimica Acta 362 (2009) 3777–3784
3783
40
25
20
15
10
5
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
30
20
TGA
DTA
TGA
DTA
10
0
-10
-20
-30
-40
-50
-60
0
-5
-10
-15
-20
10 110 210 310 410 510 610 710 810
10
110
210
310
410
510
610
Temperature (ºC)
Temperature (ºC)
Fig. 6. Thermal behavior of 2.
Fig. 5. Thermal behavior of 1.
0.85
0.8
b
0.75
0.7
1.2
0.65
0.6
a
1
0
0.5
1
1.5
2
2.5
3
Hg2+/HL
0.8
0.6
0.4
0.2
0
260
300
340
380
420
460
500
540
580
Wavelength (nm)
Fig. 7. (a) Electronic absorption spectra of ligand [HL] in MeOH (5.0 Â 10À5 M) in the presence of increasing concentration of mercury(II) acetate at room temperature. (b)
Corresponding mole ratio plot at 400 nm.
1.1
b
0.9
1.2
0.7
0.5
0.3
a
1
0.8
0.6
0.4
0.2
0
0.5
1
1.5
2
2.5
3
Hg2+/HL
0
260
300
340
380
420
460
500
540
580
Wavelength (nm)
Fig. 8. (a) Electronic absorption spectra of ligand [HL] in MeOH (5.0 Â 10À5 M) in the presence of increasing concentration of mercury(II) thiocyanate at room temperature (b)
Corresponding mole ratio plot at 373 nm.

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[18] G.-H. Cui, J.-R. Li, J.-L. Tian, X.-H. Bu, S.R. Batten, Cryst. Growth Des. 5 (2005)
1775.
[19] Y.B. Go, X.-Q. Wang, E.V. Anokhina, A.J. Jacobson, Inorg. Chem. 44 (2005)
8265.
[20] Y.-Z. Zheng, M.-L. Tong, X.-M. Chen, New J. Chem. 28 (2004) 1412.
[21] Z. Popovic, D. Matkovic-Calogovic, J. Popovic, I. Vickovic, M. Vickovic, D. Vikic-
Topic, Polyhedron 26 (2007) 1045.
[22] Z. Popovic, V. Roje, G. Pavlovic, D. Matkovic-Calogovic, M. Rajic, G. Giester,
Inorg. Chim. Acta 322 (2001) 65.
equations [41,42], using a non-linear least-squares curve fitting
program KINFIT [43]. The conditional formation constants were eval-
uated as log K = 4.25 0.003 and log K = 4.55 0.001 for com-
pounds 1 and 2, respectively.
Appendix A. Supplementary material
[23] D.S. Moore, S.D. Robinson, Adv. Inorg. Chem. Radiochem. 30 (1988) 1.
[24] M. Payehghadr, M.K. Rofouei, A. Morsali, M. Shamsipur, Inorg. Chim. Acta 360
(2006) 1792.
[25] M.K. Rofouei, M. Shamsipur, M. Payehghadr, Anal. Sci. 22 (2006) x79.
[26] M.R. Melardi, M.K. Rofouei, J. Massomi, Anal. Sci. 23 (2007) x67.
[27] M. Hematyar, M.R. Rofouei, Anal. Sci. 24 (2008) x117.
[28] G.M. Sheldrick, SHELXTL v. 5.10, Structure Determination Software Suite, Bruker
AXS, Madison, Wisconsin, USA, 1998.
CCDC 665839 and 665841 contain the supplementary crystal-
lographic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.ica.2009.04.041.
[29] L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565.
[30] Mercury 1.4.1, Copyright Cambridge Crystallographic Data Centre, 12 Union
Road, Cambridge, CB2 1EZ, UK, 2001–2005.
References
[31] R. Bala, R.P. Sarma, R. Sharma, B.M. Kariuki, Inorg. Chem. Commun. 9 (2006)
852.
[32] M.M. Raj, A. Dharmaraja, S.J. Kavitha, K. Panchanatheswaran, D.E. Lynch, Inorg.
Chim. Acta 360 (2007) 1799.
[33] S.P. Argent, H. Adams, T. Riis-Johannessen, J.C. Jeffery, L.P. Harding, W. Clegg,
R.W. Harrington, M.D. Ward, Dalton Trans. (2006) 4996.
[34] R. Taylor, O. Kennard, J. Am. Chem. Soc. 104 (1982) 5063.
[35] G.R. Desiraju, Acc. Chem. Res. 24 (1991) 290.
[1] F.C. Liu, Y.F. Zeng, J.R. Li, X.H. Bu, H.J. Zhang, J. Ribas, Inorg. Chem. 44 (2005)
7298.
[2] F.S. Gerhard, J.M. Tshepo, Chem. Rev. 100 (2000) 3483.
[3] M. Dohyun, K. Sangmi, P. Jaejoon, S.L. Myoung, J. Am. Chem. Soc. 128 (2006)
3530.
[4] A.V. Davis, K.N. Raymond, J. Am. Chem. Soc. 127 (2005) 7912.
[5] O.R. Evans, W. Lin, Acc. Chem. Res. 35 (2002) 511.
[6] H.W. Roesky, M. Andruh, Coord. Chem. Rev. 236 (2003) 91.
[7] K. Biradha, Cryst. Eng. Commun. 5 (2003) 374.
[36] M. Horner, G. Manzoni de Oliveira, J.S. Bonini, H. Fenner, J. Organomet. Chem.
691 (2006) 655.
[8] X.M. Chen, G.F. Liu, Chem. Eur. J. 8 (2002) 4811.
[37] M. Horner, G. Manzoni de Oliveira, J.A. Naue, J. Daniels, J. Beck, J. Organomet.
Chem. 691 (2006) 1051.
[38] M. Horner, G. Manzoni de Oliveira, M.B. Behm, Z. Allg. Anorg. Chem. 632
(2006) 615.
[39] M. Horner, G. Manzoni de Oliveira, E.G. Koehler, L.C. Visentin, J. Organomet.
Chem. 691 (2006) 1311.
[9] S.R. Batten, B.F. Hoskins, R. Robson, J. Am. Chem. Soc. 117 (1995) 5385.
[10] G.B. Gardner, D. Venkataraman, J.S. Moore, S. Lee, Science 374 (1995) 792.
[11] B.F. Hoskins, R. Robson, J. Am. Chem. Soc. 112 (1990) 1546.
[12] M.A. Withersby, A.J. Blake, N.R. Champness, P.A. Cooke, P. Hubberstey, W.S. Li,
W.S. Li, M. Schröder, Inorg. Chem. 38 (1999) 2259.
[13] A.J. Blake, N.R. Champness, P.A. Cooke, J.E.B. Nicolson, C. Wilson, J. Chem. Soc.,
Dalton Trans. (2000) 3811.
[40] X.-P. Li, J.-Y. Zhang, Y. Liu, M. Pan, S.-R. Zheng, B.-S. Kang, C.-Y. Su, Inorg. Chim.
Acta 360 (2007) 2990.
[14] L. Carlucci, G. Ciani, D.M. Proserpio, S. Rizzato, New J. Chem. 27 (2003) 483.
[15] J.-R. Li, X.-H. Bu, R.-H. Zhang, J. Ribas, Cryst. Growth Des. 5 (2005) 1919.
[16] Y.-T. Wang, H.-H. Fan, H.-Z. Wang, X.-M. Chen, Inorg. Chem. 44 (2005) 4148.
[17] I.S. Lee, D. MokShin, Y.K. Chung, Chem. Eur. J. 10 (2004) 3158.
[41] M.R. Ganjali, A. Rouhollahi, A.R. Mardan, M. Shamsipur, J. Chem. Soc., Faraday
Trans. 94 (1998) 1959.
[42] A. Fakhari, M. Shamsipur, J. Inclusion Phenom. 26 (1996) 243.
[43] V.A. Nicely, J.L. Dye, J. Chem. Edu. 49 (1971) 443.