Syntheses, crystal structure and luminescent properties of cadmium complexes based on 2,6-bis(1-phenylbenzimidazol-2-yl)pyridine

Article abstract of DOI:10.1016/j.saa.2012.06.039

Two cadmium complexes, Cd(bpbp)Cl₂ (complex 1) and [Cd(bpbp)₂](ClO₄)₂ (complex 2), based on 2,6-bis(1-phenylbenzimidazol-2-yl)pyridine (bpbp), were synthesized and characterized by X-ray single crystal structure analyses. For complex 1: crystal system, monoclinic, space group, C2/c, a = 27.427(3) A, b = 13.4495(15) A, c = 14.8381(17) A, β = 106.635(2)°, V = 5244.4(10) A³, Z = 8. It is a neutral complex. The Cd(II) ion distorted trigonal bipyramidal geometry is five-coordinated by three nitrogen atoms from ligand (bpbp) and two chlorine ions. For complex 2: crystal system, triclinic, space group, P-1, a = 13.4791(15) A, b = 13.8506(16) A, c = 16.5839(19) A, α = 94.202(2)°, β = 106.948(2)°, γ = 94.872(2)°, V = 2935.3(6) A³, Z = 2. It is an ionic complex. The Cd(II) ion octahedral geometry is six-coordinated by six nitrogen atoms from two ligand (bpbp). Both complexes emit blue luminescence with emission peaks at 420 and 430 nm in solid state and with emission peaks at 415 and 425 nm in DMF solution. In complex 1 absorption spectra, there is not only the free ligand absorption peak at 310 nm, but also shows strong Cd-Cl charge transfer peak at 350 nm in DMF solution.

Full text of DOI:10.1016/j.saa.2012.06.039

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 464–469
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Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Syntheses, crystal structure and luminescent properties of cadmium
complexes based on 2,6-bis(1-phenylbenzimidazol-2-yl)pyridine
b
c
a
a
Sheng-Gui Liu a, , Lin-Ping Zhang , Jian Liu , Wen-Yi Su , Xiao-Bo Shi
⇑
a School of Chemistry Science and Technology, Zhanjiang Normal University, Zhanjiang 524048, People’s Republic of China
b Key Laboratory of Science & Technology of Eco-Textile (Ministry of Education), Donghua University, Shanghai 201620, People’s Republic of China
c School of New Energy Science and Engineering, Xinyu University, Xinyu 338004, People’s Republic of China
g r a p h i c a l a b s t r a c t
h i g h l i g h t s
Two cadmium complexes based on 2,6-bis(1-phenylbenzimidazol-2-yl)pyridine (bpbp), were synthe-
sized and characterized by X-ray single crystal structure analyses. Both complexes emit blue lumines-
cence in solid state and in solution.
"
"
"
"
Two new cadmium complexes based
on 2,6-bis(1-phenylbenzimidazol-2-
yl)pyridine were synthesized.
The two cadmium complexes were
characterized by single X-ray
analyses.
The two cadmium complexes emit
blue luminescence in solid state and
in solution.
The luminescence of the two
cadmium complexes are
predominantly from the ligand
p⁄
? p transitions fluorescence.
a r t i c l e i n f o
a b s t r a c t
Article history:
Two cadmium complexes, Cd(bpbp)Cl2 (complex 1) and [Cd(bpbp)2](ClO4)2 (complex 2), based on 2,6-
bis(1-phenylbenzimidazol-2-yl)pyridine (bpbp), were synthesized and characterized by X-ray single
crystal structure analyses. For complex 1: crystal system, monoclinic, space group, C2/c,
a = 27.427(3) Å, b = 13.4495(15) Å, c = 14.8381(17) Å, b = 106.635(2)°, V = 5244.4(10) Å3, Z = 8. It is a neu-
tral complex. The Cd(II) ion distorted trigonal bipyramidal geometry is five-coordinated by three nitrogen
atoms from ligand (bpbp) and two chlorine ions. For complex 2: crystal system, triclinic, space group, P-1,
Received 29 April 2012
Received in revised form 5 June 2012
Accepted 25 June 2012
Available online 4 July 2012
Keywords:
a = 13.4791(15) Å, b = 13.8506(16) Å, c = 16.5839(19) Å,
a = 94.202(2)°, b = 106.948(2)°, c = 94.872(2)°,
Benzimidazole
Cadmium complex
Crystal structure
Luminescence
V = 2935.3(6) Å3, Z = 2. It is an ionic complex. The Cd(II) ion octahedral geometry is six-coordinated by
six nitrogen atoms from two ligand (bpbp). Both complexes emit blue luminescence with emission peaks
at 420 and 430 nm in solid state and with emission peaks at 415 and 425 nm in DMF solution. In complex
1 absorption spectra, there is not only the free ligand absorption peak at 310 nm, but also shows strong
Cd–Cl charge transfer peak at 350 nm in DMF solution.
Ó 2012 Elsevier B.V. All rights reserved.
⇑
Corresponding author. Tel.: +86 759 3183176; fax: +86 759 3183510.
E-mail address: lsgui@sohu.com (S.-G. Liu).
1386-1425/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.saa.2012.06.039

S.-G. Liu et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 464–469
465
Synthesis of [Cd(bpbp)Cl2] (1)
Introduction
To an alcohol solution (10 ml) of CdCl2 (367 mg, 2.0 mmol) was
added an alcohol solution (20 ml) of bpbp (927 mg, 2.0 mmol). The
reaction mixture was stirred for 30 min at room temperature.
White crystals were obtained from room evaporation of alcohol,
yield 993 mg (76%). Anal. Calcd. for C31H21Cl2N5Cd ([Cd(bpbp)Cl2]):
C, 57.56%; H, 3.27%; N, 10.83%. Found: C, 57.29%; H, 3.41%; N,
10.73%. Selected IR data (KBr, cmÀ1): 3448, 1658, 1495, 1443,
1378, 1255, 1106, 1061, 1002, 877, 808, 755, 679.
In recent years, luminescent metal complexes have attracted an
increasing attention in many areas of chemistry, biology, medical
and material science [1–9]. Their functions as emitter material in
luminescence devices and luminescent chemosensor are particu-
larly prominent. Luminescent chemosensor have the advantage
of possessing high sensitivity and selectivity, as well as providing
online and real-time analysis [10–12]. One of simple strategy for
designing luminescent coordination compounds is to organize d10
electronic configuration metal ions with chromophore ligand. The
origins of emission arise from the transitions of p⁄
–p within ligand.
Synthesis of [Cd(bpbp)2](ClO4)2ÁCH3CH2OH (2)
This emission could be efficiently enhanced in coordination com-
plex due to increasing of the rigidity of the ligand and reducing
of energy loss by radiationless thermal vibrations [13,14]. The de-
sign and synthesis of desired structure luminescent complex is a
challenge because the assembly of metal ion with ligand is sensi-
tive to the delicate synthetic conditions [15].
To an alcohol solution (10 ml) of Cd(ClO4)Á6H2O (420 mg,
2.0 mmol) was added an alcohol solution (20 ml) of bpbp
(993 mg, 2.0 mmol). The reaction mixture was stirred for 30 min
at room temperature. On recrystallization from ethanol, white
crystals were obtained. Yield: 987 mg (79%). Anal. Calcd. for
2,6-Bis(benzimidazol-2-yl)pyridine usually functions as triden-
tate ligand, but the five N atoms all can coordinate to metal center
ion, even if with the same central ion, different counter-anion
involved, different pH value, will result in different complex
[16,17]. The author investigated the syntheses, structures and their
blue luminescent properties of Zn(II), Cd(II), In(III) dichloride com-
plexes based on 2,6-bis(benzimidazolyl)pyridine [18,19]. 2,6-Bis-
(benzimidazol-2-yl)pyridine can easily be tailored at NH group
[20]. The substitution of the N–H bond of 2,6-bis(benzimidazol-
yl)pyridine will change their many properties (e.g. acid–base
degree, solubility and photophysical properties). The luminescence
analysis is favorable to trace analysis for such environmental toxic
ions as cadmium. It is necessary to investigate that how cadmium
ions coordinate to luminescent chromophore so as to set up lumi-
nescence analysis method of cadmium. As part of our continuing
studies, herein we synthesized two cadmium complexes based
on 2,6-bis(1-phenylbenzimidazol-2-yl)pyridine (bpbp) to investi-
gate their luminescent properties.
C
64H48N10Cl2O9Cd ([Cd(bpbp)2](ClO4)2ÁCH3CH2OH): C, 59.85, H,
3.77% N, 10.90%: C, 59.49%, 3.81, N, 10.60%. Selected IR data (KBr,
cmÀ1): 3473, 3065, 1594, 1502, 1460, 1411, 1378, 1336, 1293,
1200, 1094, 1002, 877, 818, 750, 696, 617.
X-ray crystallography
Single crystal structure determination complexes were per-
formed on a Bruker SMART APEX CCD diffractometer equipped
with a normal focus, 3 kW sealed tube X-ray source and graphite
monochromated Mo–K radiation (k = 0.71073 Å) at 173 K, operat-
a
ing at 50 kV and 30 mA. The structures were solved by direct meth-
ods by using program SHELXTL. Absorption correction adopted
semi-empirical from equivalents. Fourier difference techniques,
and refined by full-matrix least-squares. All non-hydrogen atoms
in both structures were refined anisotropic displacement parame-
ters. All hydrogen atoms were theoretically added. The crystal data
are summarized in Table 1. Selected bond lengths and angles for
complex 1 are listed in Table 2, complex 2 listed in Table 3.
Table 1
Crystallographic data for complex 1 and complex 2.
Complex 1
31H21CdCl2N5
646.83
Monoclinic
C2/c
27.427(3)
13.4495(15)
14.8381(17
90
106.635(2)
90
5244.4(10)
8
1.638
Complex 2
Experimental
Formula
Formula weight
Crystal system
Space group
a/Å
C
C64H47CdCl2N10O9
1283.42
Triclinic
General
P-1
13.4791(15)
13.8506(16)
16.5839(19)
94.202(2)
106.948(2)
94.872(2)
2935.3(6)
2
1.452
0.531
1332.0
0.12 Â 0.15 Â 0.18
1.59, 27.08
À17 6 h 6 17
À17 6 k 6 17
À21 6 l 6 21
10333, 829
o-Phenylenediamine, pyridine-2,6-dicaboxyl acid and bromo-
benzene were purchased from Shanghai Aladdin Reagent Company.
All the chemicals and solvents used were analytically pure and
without further purification. The analyses (C, H and N) were made
on a Perkin–Elmer 240C elemental analyzer. 1H NMR spectroscopic
measurements were carried out on a Bruker AM-300 NMR spec-
trometer, using TMS (SiMe4) as an internal reference. The solid
infared spectra (IR) were obtained from a Bruker IFS66V vacuum-
type FT–IR spectrophotometer by using KBr pellets. The UV absorp-
tion spectra were recorded on a model UV-240 spectrophotometer
(Shimadzu, Japan). Fluorescence measurements were performed on
a Model RF-5 spectrofluorimeter (Shimadzu, Japan). 2,6-bis(1-
phenylbenzimidazol-2-yl)pyridine was synthesized according to
the literature [21,22]. This ligand structure was confirmed by
element analysis IR, and 1H NMR. Element analysis for C31H21N5,
found: C, 80.22; H, 4.67; N, 15.10, calculated: C, 80.32; H, 4.57; N,
15.11. Selected IR data (KBr, cmÀ1): 3417, 1674, 1588, 1503, 1439,
1392, 1336, 1250, 1147, 1072, 1002, 933, 874, 830, 744, 685, 575,
541, 502, 421 and 1H NMR: (CDCl3): 6.99 (d, 4H), 7.184–7.367(m,
12H), 7.876 (t, 3H), 8.08 (d, 2H).
b/Å
c/Å
a
/°
b/°
c
/°
V/Å3
Z
Density calc.mg.mÀ3
Absorption coefficient (mmÀ1
F(000)
)
1.068
2592
Crystal size
Theta range for data collection
Index ranges
0.12 Â 0.17 Â 0.47
1.5, 27.0
À24 6 h 6 35
À14 6 k 6 17
À17 6 l 6 18
5763, 352
15379, 5763, 0.032 21182, 10218, 0.025
1.09
0.6336, 0.8825
4407
R1 = 0.0327
wR2 = 0.0867
Nref, Npar
Tot., Uniq. Data, R(int)
GOF on F2
1.08
0.909, 0.938
8524
R1 = 0.0269
wR2 = 0.2873
À0.99, 1.29
Max. and min. transmission
Observed data [I > 2.0 sigma(I)]
R indices (all, data) R1, wR2
Largest diff. peak and hole e.ÅÀ3 À0.46, 0.66

466
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À
Table 2
[Cd(bpbp)2](ClO4)2 since ClO4 act as counter anions. However,
2,6-bis(benzimidazol-2-yl)pyridine (containing two NH groups)
react with Cd(ClO4)2, if in the present of triethylamine glycerol
solution, 2,6-bis(benzimidazol-2-yl)pyridine will deprotonate and
result in neutral Cd(II) complex Cd(bbp)2, whereas, it will form
ionic complex [Cd(bbp)2](ClO4)2, if in alcohol solution absence of
triethylamine [23,24]. In the IR spectra of free ligand, there are
two peaks at 1678 and 1588 cmÀ1, but there is only a strong peak
at 1653 cmÀ1 in complex 1 and 1592 cmÀ1 in complex 2, which
shows that coordinated Cd(II) will obviously affect skeletal vibra-
tion of the aromatic rings. In addition, in complex 2, there is a
Selected bond lengths (Å) and angles (°) for complex 1.
Cd1–Cl2
2.4412(8)
2.332(2)
2.311(3)
1.327(4)
1.337(4)
1.386(4)
112.59(3)
107.20(6)
99.81(6)
102.28(6)
131.77(8)
Cd1–Cl1
Cd1–N3
N1–C1
2.4635(8)
2.415(2)
1.382(4)
1.342(4)
1.321(4)
Cd1–N1
Cd1–N4
N1–C13
N3–C18
N3–C14
N4–C19
N4–C31
Cl2–Cd1–Cl1
Cl2–Cd1–N3
Cl1–Cd1–N1
Cl1–Cd1–N4
N1–Cd1–N4
Cl2–Cd1–N1
Cl2–Cd1–N4
Cl1–Cd1–N3
N1–Cd1–N3
N3–Cd1–N4
110.63(6)
99.46(6)
140.09(6)
67.98(8)
67.54(8)
strong peak at 1090 cmÀ1, which shows ClO4 in this complex.
À
Crystal structures
Table 3
Selected bond lengths (Å) and angles (°) for complex 2.
The ORTEP drawing of complex 1 is shown in Fig. 1. The central
Cd(II) ion is five-coordinated and surrounded by a N3Cl2 environ-
ment, adopting a distorted trigonal bipyramidal geometry. The li-
gand (bpbp) affords three N atoms to coordinate to Cd(II) and
two chloride ions lie each side of the planar pyridine ring. The bond
length of Cd1–N4, Cd1–N1, Cd1–N3 are respectively 2.311(2),
2.332(2), 2.415(2) Å. The average bond length of Cd–N is 2.359 Å.
The bond length of Cd1–Cl1 and Cd1–Cl2 are 2.4634(8),
2.4412(8) Å, respectively. The average bond length of Cd–Cl is
2.4513 Å. The bond angles of N3–Cd1–N4, N3–Cd1–N1, N3–Cd1–Cl1,
N3–Cd1–Cl2 are 67.54(8), 67.98(8)°, 140.10(6), 107.20(6)°. The
three atoms N1, N3, N4 chelate center metal cadmium to result in
the formation of a coplanar of two benzimidazole rings and the
pyridine ring of the ligand, but steric strain make the center cad-
mium ion deviate from this plane (mean deviation = 0.4841°).
The two substitute phenyl rings are inclined with the two benz-
imidazole rings, respectively. The dihedral angle between substi-
tuted phenyl ring and benzimidazole ring are 56.7° for phenyl
ring C7–C12, 58.9° for phenyl ring C20–C25. The crystal packing of
complex 1 is shown in Fig. 2. Two adjacent molecules form a dimer
Cd1–N9
Cd1–N8
Cd1–N6
2.290(6)
2.339(5)
2.385(6)
121.4(2)
116.04(19)
69.9(2)
138.8(2)
69.38(19)
80.0(2)
Cd1–N4
Cd1–N3
Cd1–N1
N9–Cd1–N8
N9–Cd1–N3
N8–Cd1–N3.
N4–Cd1–N6
N3–Cd1–N6
N4–Cd1–N1
N3–Cd1–N1
2.305(6)
2.361(6)
2.398(6)
69.9(2)
111.6(2)
172.5(2)
82.5(2)
107.99(19)
138.5(2)
69.1(2)
N9–Cd1–N4
N4–Cd1–N8
N4–Cd1–N3
N9–Cd1–N6
N8–Cd1–N6
N9–Cd1–N1
N8–Cd1–N1
N6–Cd1–N1
104.4(2)
104.5(2)
Result and discussion
Synthesis, IR for complexes
Reaction of 2,6-bis(1-phenylbenzimidazol-2-yl)pyridine (bpbp)
with CdCl2 in alcohol solution resulted in complex 1. Reaction of
2,6-bis(1-phenylbenzimidazol-2-yl)pyridine with Cd(ClO4)2 in eth-
anol produce complex 2. It is important to choose anion of metal
salt in the formation of complex in this coordination reaction. Dif-
ferent anions inorganic metal salt can produce different complex.
When ligand (bpbp) react with CdCl2, it will result in neutral
complex Cd(bpbp)Cl2, although bpbp is two equivalent of CdCl2.
If bpbp react with Cd(ClO4)2, it will result in ionic complex
by two point-to-face C–H. . .
p weak interactions between substi-
tuted benzene protons and substituted benzene ring (the distance
of hydrogen atom to the center of substituted benzene is 2.997 Å),
substituted benzene protons and benzimidazole benzene ring (the
distance of hydrogen atom to the center of benzimidazole benzene
Fig. 1. Molecular structure of complex 1. Hydrogen atoms have been omitted for clarity (ORTEP, 50% ellipsoids).

S.-G. Liu et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 464–469
467
Fig. 2. The crystal packing of complex 1 (the broken line stand for weak interaction).
planar is 14.0°, which show Cd(II) atom in a greatly distorted octa-
hedral geometry. The dihedral angle between substituted phenyl
ring and benzimidazole ring are 62.8° for phenyl ring C8–C13
,
87.9° for phenyl ring C22–C26, 44.2° for phenyl ring C40–C46, 59.1°
for phenyl ring C55–C60. The bond length of Cd1–N9, 2.290(6),
Cd1–N4 2.305(6), Cd1–N8, 2.339(5), Cd1–N3 2.361(6), Cd1–N6,
2.385(6), Cd1–N1 2.398(6). The average bond length of Cd–N is
2346 Å. which fall into the range of the reported Cd–N distanceÀs
[25]. The crystal packing of complex 2 is shown in Fig. 4, ClO4
counter-ions are included in the crystal lattice not only by electro-
static interaction between perchlorate ions and coordinated cat-
ions [Cd(bpbp)2]2+, but also by C–HÁ Á ÁO weak hydrogen bonds.
(The distance: C9–H9AÁ Á ÁO5i = 3.257, C16–H16AÁ Á ÁO7 = 3.32, C45
–
H45AÁ Á ÁO1ii = 3.348, C51–H51AÁ Á ÁO11iii = 3.26, C60–H60AÁ Á ÁO13 = 3.219,
C
64–H64AÁ Á ÁO10iv = 3.50 Å, Symmetry codes: i: 3 À x; 3 À y, 3 À z;
ii: 2 À x; 1 À y, 2 À z; iii: 2 À x, 2 À y, 3 À z; iv: 2 À x, 3 À y, 3 À z).
Photophysical properties
The UV–Vis absorption and liquid luminescence spectra were
recorded at a concentration of 1.0 Â 10À5 mol/L in DMF at room
temperature. The UV–Vis absorption spectra of free ligand and
complexes 1 and 2 are shown in Fig. 5. The ligand and both
complexes all have absorption in the range of 270–390 nm. The
maximal absorption are all at about 310 nm, which are blue shift
by 20 nm than cadmium 2,6-bis(1-phenylbenzimidazol-2-yl)pyri-
dine dichloride complex, which can be assigned to intraligand
Fig. 3. Molecular structure of [Cd(bpbp)2]2+ cation. All hydrogen atoms of bpbp,
alcohol solvent molecule and counter anions have been omitted for clarity (ORTEP,
50% ellipsoids).
p
?
p⁄ transitions. There is one more peak observed at 350 nm
for complex 1, which probably arise from metal-chloride charge
transfer since the ligand and complex 2 do not show this peak, this
behavior were also observed in cadmium, indium 2, 6-bis(ben-
zimidazol-2-yl)pyridine dichloride complexes [19].
is 3.176 Å), and C–HÁ Á ÁCl weak interaction (the distance of HÁ Á ÁCl is
2.832 Å). These dimers form a chain through benzimidazole ben-
zene ring
benzene ring center is 3.541 Å).
p
–
p
weak interactions along a axis (the distance of two
The free ligand and complexes 1 and 2 all display blue lumines-
cence in solid state (Fig. 6). The free ligand 2,6-bis(1-phen-
ylbenzimidazol-2-yl)pyridine is also a blue luminescent compound
similar to 2,6-bis(benzimidazol-2-yl)pyridine[19]. The complexes
all show broad luminescent bands since their luminescence are pre-
The ORTEP drawing for complex 2 with atom numbering is
shown in Fig. 3. The center Cd(II) ion has N6 coordination sphere,
being bound by two bpbp ligand. In every ligand, the two benz-
imidazole rings and center pyridine ring form a good planar (mean
deviation = 0.2364°, 1.38°), the dihedron between the two ligand
dominantly from the ligand p⁄
?
p
transitions fluorescence. Under
excitation of 370 nm wavelength light, the complexes 1 and 2 exhi-

468
S.-G. Liu et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 464–469
Fig. 4. The packing diagram of the complex 2 viewing along b axis (the broken lines showing C–HÁ Á ÁO weak hydrogen bonds).
1.8x104
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
-0.1
430
1.6x104
[Cd(bpbp)2](ClO4)2
1.4x104
420
1.2x104
[Cd(bpbp)2](ClO4)2
310
350
1.0x104
8.0x103
6.0x103
4.0x103
2.0x103
Cd(bpbp)Cl2
Cd(bpbp)Cl2
bpbp
440
bpbp
350
250
275
300
325
375
400
380
400
420
440
460
480
500
520
540
Wavelength (nm)
wavelength (nm)
Fig. 6. Fluorescence spectra of the ligand, complexes
(kex = 370 nm).
1 and 2 in solid state
Fig. 5. UV–visible absorption spectra of bpbp, complexes 1 and 2 in DMF solution.
ligand, complexes 1 and 2 also exhibit luminescence with the
maximal peaks at 380, 415 and 425 nm, respectively (Fig. 7). In com-
parison with the solid state, there are only slight 5 nm blue-shifts for
the complexes 1 and 2 but 60 nm blue-shift for free ligand, which
show DMF solvent affect luminescence of free ligand much greatly
than complexes 1 and 2 (see Fig. 7).
bit blue luminescent with the maximal peaks at 420 and 430 nm
which is 20, 10 nm red-shift compared to the free ligand (440 nm)
respectively. Notably, it is observed that the luminescent intensity
of two complexes increase than free ligand because of effective in-
crease of rigidity of ligand after coordination to cadmium ion. The
luminescent intensity of complex 2 is stronger than complex 1 is
due to that there are two luminescent ligand (bpbp) molecules in
complex 2 and one in complex 1. The red shift of complex 1 and 2
than free ligand (bpbp) may be caused by the differences of the
coplanar of two benzimidazole rings and center pyridine rings of
ligands and the dihedral angle between substituted phenyl rings
and benzimidazole rings in the two complexes in solid state. In
DMF solution, under excitation of 330 nm wavelength light, the free
Conclusion
Two cadmium complexes, Cd(bpbp)Cl2 and [Cd(bpbp)2](ClO4)2,
based on 2,6-bis(1-phenylbenzimidazol-2-yl)pyridine were syn-
thesized and characterized by X-ray single crystal structure analy-

S.-G. Liu et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 464–469
469
900
750
600
450
300
150
0
Appendix A
425
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic Data Centre, CCDC
no. 873909 for complex 1 and no. 873910 for complex 2. Copies of
this information may be obtained from The Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK (www: http://www.ccdc.
cam.ac.uk).
Cd(bpbp)2(ClO4)2
Cd(bpbp)2Cl2
410
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Acknowledgments
This work was financially supported by the Natural Science
Foundation of Guangdong Province (NO. 10152404801000017)
and the Science and Technology Program of JiangXi Education
Department (No. GJJ12653).
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