Synthesis, crystal structure and luminescence property of a chiral magnesium (II) mixed-ligand complex [Mg(H2O)2(phen)(HBDC) 2](phen)

Article abstract of DOI:10.1007/s10870-010-9853-0

A new mixed-ligand complex of [Mg(H₂O)₂(phen)(HBDC) ₂](phen) (phen = 1, 10-phenanthroline, H₂BDC = 1,3-benzene dicarboxylic acid) has been synthesized and its crystal structure determined by single-crystal X-ray diffraction. It is noteworthy that this complex was formed from achiral reactants, and found to crystallize in the chiral space group C2. Structure analysis shows that each Mg(II) ion is coordinated by the two nitrogen atoms of phen, one oxygen atom from each of the two 1,3-HBDC molecules and one oxygen atom from each of the two water molecules, leading to a distorted octahedral geometry. The mixed-ligand complexes are assembled into a two-dimensional supramolecular network through the formation of intermolecular hydrogen bonds. The luminescence property and thermal stability behavior of the complex were also investigated. The complex shows a strong blue luminescence emission. Crystal data: a = 24.5856(16), b = 10.1598(6), c = 7.1460(4) A, β = 105.226(2)°, V = 1722.30(18)A³, Z = 2, R ₁ = 0.0367, wR ₂ = 0.0833 [I>2σ(I)].

Full text of DOI:10.1007/s10870-010-9853-0

J Chem Crystallogr (2011) 41:143–146
DOI 10.1007/s10870-010-9853-0
ORIGINAL PAPER
Synthesis, Crystal Structure and Luminescence Property
of a Chiral Magnesium (II) Mixed-ligand Complex
[Mg(H2O)2(phen)(HBDC)2](phen)
•
Ai-xiang Chen Gang Liu Hui Li
•
•
•
Ji-de Wang Fan Yue
Received: 20 February 2009 / Accepted: 17 July 2010 / Published online: 11 August 2010
Ó Springer Science+Business Media, LLC 2010
Abstract A new mixed-ligand complex of [Mg(H2O)2
(phen)(HBDC)2](phen) (phen = 1, 10-phenanthroline,
H2BDC = 1,3-benzene dicarboxylic acid) has been syn-
thesized and its crystal structure determined by single-
crystal X-ray diffraction. It is noteworthy that this complex
was formed from achiral reactants, and found to crystallize
in the chiral space group C2. Structure analysis shows that
each Mg(II) ion is coordinated by the two nitrogen atoms
of phen, one oxygen atom from each of the two 1,3-HBDC
molecules and one oxygen atom from each of the two water
molecules, leading to a distorted octahedral geometry. The
mixed-ligand complexes are assembled into a two-
dimensional supramolecular network through the formation
of intermolecular hydrogen bonds. The luminescence pro-
perty and thermal stability behavior of the complex were
also investigated. The complex shows a strong blue lumines-
devices [1, 2], asymmetric catalysis [3, 4], and enantiose-
lective synthesis [5, 6]. Most chiral complexes are assembled
from chiral molecules, while chiral complexes synthesized
from completely achiral molecules are less common [7, 8].
Up to now, the design and control over coordination com-
pounds has been mainly focused on the incorporation of
transition metal ions as coordination centers, whereas less
attention has been paid to the main group metal ions [9–12].
In this report, a new chiral crystal [Mg(H2O)2(phen)
(HBDC)2](phen) was synthesized using magnesium(II) as
the center ion, coordinated by achiral organic ligands,
1,10 phenanthroline (phen) and 1,3-benzene dicarboxyate
(1,3-HBDC), and water. The luminescence property of
[Mg(H2O)2(phen)(HBDC)2](phen) was investigated and
found to show a strong blue luminescence emission.
cence emission. Crystal data: a = 24.5856(16), b = 10.1598(6),
3
˚
˚
c = 7.1460(4) A, b = 105.226(2)8, V = 1722.30(18)A , Z =
2, R1 = 0.0367, wR2 = 0.0833 [I[2r(I)].
Experimental Section
Materials and Physical Measurements
Keywords Chiral complex Á Mg(II) ion Á Crystal
structure Á Luminescence
All reagents were commercially available and used as
received. Infrared spectra were recorded on a Bruker Equi-
nox-55 spectrophotometer in the 500–4000 cm-1 region
using [Mg(H2O)2(phen)(HBDC)2](phen) in KBr pellet form.
Elemental analysis (CHNO) was determined using a Thermo
Flash EA 1112-Elmer elemental analyzer. The luminescence
property was measured using a HITACHI F-4500 lumines-
cence spectrophotometer and the thermal analysis was per-
formed using a NETZSCH STA449C analyzer.
Introduction
The design and synthesis of novel chiral crystals has
attracted intense interest owing to the realization of their
potential use as functional materials in nonlinear optical
A. Chen Á G. Liu Á H. Li Á J. Wang Á F. Yue (&)
Key Laboratory of Oil and Gas Fine Chemicals,
Ministry of Education, Xinjiang University, Urumqi 830046,
Xinjiang, People’s Republic of China
Synthesis of [Mg (H2O)2(phen)(HBDC)2](phen)
Mg(NO3)2Á6H2O (1.0 mmol), phen (1.0 mmol), 1, 3-H2BDC
(1.0 mmol) were reacted together in methanol/H2O
e-mail: xjyuefan@yahoo.com.cn
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J Chem Crystallogr (2011) 41:143–146
˚
(10 mL/20 mL), and the resulting solution was left to stand at
70 °C for several days, where after colourless block-like
crystalswereformed. Yield:42% (basedonMg). Anal. Calcd.
for C40H30N4O10Mg(%):C, 63.97;H, 4.01; N, 7.46; O, 21.30.
Found: C, 64.05; H, 3.97; N, 7.43; O, 21.39. IR spectrum
(cm-1): 1702(s), 1609(ms), 1557(s), 1423(ms), 1395(s),
929(ms), 868(d) and 842(ms).
Table 3 Hydrogen bond lengths (A) and angles (°) in compound
D–H
HÁÁÁA
D–A
\DHA
O(5)-H(5A)ÁÁÁO(2)a
0.84
1.15(7)
b
1.95
2.731(3)
2.899(3)
154.5
O(5)–H(5WA)ÁÁÁN(2)b
1.84(7)
150(5)
a
Symm code: -x, y, -z ? 1; x - 1, y, z
displacement parameters in the refinement. The hydrogen
atoms were obtained from difference Fourier maps and a
riding model was used.
X-ray Crystallography
Crystallographic data for the crystal is summarized in
Tables 1, 2 and 3. The data were collected using MoKa
˚
radiation (k = 0.71073 A) on an R-Axis Spider diffractom-
Results and Discussion
eter at 153(2) K. The cell dimensions and space group were
determined according to established procedures [13]. The
structures were solved bydirect methodsusing the SHELXTL
program and refined by full-matrix least-squares tech-
niques. The non-hydrogen atoms were assigned anisotropic
The coordination environment of the Mg(II) ion in
[Mg(H2O)2(phen)(HBDC)2](phen) is shown in Fig. 1. The
compound crystallizes in the monoclinic chiral space group
C2. The Flack parameter was found to be -0.1(4), con-
firming that the absolute structure could be determined [14].
Each Mg(II) ion is coordinated by the two nitrogen atoms of
phen, one oxygen atom from each of the two 1,3-HBDC
molecules and one oxygen atom from each of the two water
molecules, leading to a distorted octahedron geometry.
Bond lengths of Mg(1)–N (1), Mg(1)–O(5) and Mg(1)–O(1)
Table 1 Crystallographic data and structure refinement for
[Mg(H2O)2(phen)(HBDC)2](phen)
Empirical formula
Formula weight
Crystal system
Space group
C40N4O10H30Mg
750.99
˚
˚
˚
are 2.219(2) A, 2.0651(2) A, 2.0538(2) A. The basal plane
is formed by O(1), O(1A), N(1), N(1A), and the axial sites
are occupied by O(5) and O(5A). Bond angles of O(5)–
Mg(1)–O(1), O(5)–Mg(1)–N(1), O(5)–Mg(1)–O(5A) are
91.96(7)°, 85.83(8)°, 178.0(8)°, respectively. The com-
plexes are assembled into a two-dimensional supramolecu-
lar network through the formation of intermolecular
hydrogen bonds, as shown in Fig. 2.
Monoclinic
C2
˚
a, (A)
24.5856 (2)
10.1598 (6)
7.1460 (4)
105.226 (2)
1722.30 (2)
2
˚
b, (A)
˚
c, (A)
b, (°)
3
˚
V, (A )
Z
Dc (g cm-1
Abs coef. (mm-1
)
1.448
)
0.122
Crystal size (mm)
T(K)
0.63 9 0.25 9 0.23
153 (2)
F000
780
Reflections collected
Unique reflections
Range (°)
8528
3905
3.26–27.48
-0.1(4)
Flack parameter
R [I [ 2(I)]
R1 = 0.0367, wR2 = 0.0833
˚
Table 2 Selected bond lengths (A) and angles (°) for compound
Mg(1)–O(1)
2.0538(2)
2.0651(2)
102.07(1)
165.66(8)
85.83(8)
Mg(1)–N(1)
2.219(2)
Mg(1)–O(5)
O(1)a–Mg(1)–O(1)
O(1)a–Mg(1)–N(1)
O(5)–Mg(1)–N(1)
a
O(1)a–Mg(1)–O(5)
O(5)–Mg(1)–O(5)a
N(1)–Mg(1)–N(1)a
89.25(7)
178.08(1)
75.23(1)
Fig. 1 The coordination environment of the Mg(II) ion in
[Mg(H2O)2(phen)(HBDC)2](phen) in 30% probablility
Symm code: -x, y, -z ? 1
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J Chem Crystallogr (2011) 41:143–146
145
100
80
60
40
20
0
100
200
300
400
500
600
700
Temperature(°C)
Fig. 4 TGA curve for [Mg(H2O)2(phen)(HBDC)2](phen)
80
Fig. 2 The two-dimensional hydrogen bonded network viewed along
the c-axis, and the a-axis is horizontal
60
40
20
0
300
400
500
600
Wavelength (nm)
Fig. 5 Solid-state emission spectra for [Mg(H2O)2(phen)(HBDC)2](-
phen) at room temperature
of 46.33%, corresponding to the loss of phenanthroline
molecules from the complex (calcd. 47.99%). The last
weight loss of 43.08% from 480 to 590 °C corresponded to
the loss of H2BDC molecules from the complex (calcd.
39.98%). The final pyrolysis product was MgO, as shown
in Fig. 4.
Fig. 3 The three-dimensional network viewed along c-axis in the
complex, and the b-axis is horizontal
The structures contain a phen ligand attached to
magnesium have been reported by Zhang, Skogareva, etc.
[15–22], and three structures have a cocrystalized phen
ligands hydrogen bound to water in the same manner as the
structure in the report [15–17]. The non-coordinated phen
is some disordered due to the fact that the ligand is not
locked into place as tightly as the coordinate phen.
Hydrogen bond length of O(5)–H(5A)ÁÁÁO(2)A, O(5)–
The luminescence property of the complex was inves-
tigated in the solid state at room temperature, as shown in
Fig. 5. The complex exhibited a luminescence emission
with a maximum at 409 nm upon excitation at 300 nm,
which is attributed to ligand-based emissions [5]. The blue
emission of the complex in the solid state implies that the
complex may be potentially applicable as a material for
blue light-emitting diode devices.
H(5WA)ÁÁÁN(2)B are 2.731(3) A, 2.899(3) A and bond
angles are 154.5°, 150.5°.The parallel distance between the
uncoordinated and coordinated phen ligands is 3.465 and
˚
˚
˚
3.517 A, respectively, indicating that there are strong p–p
stacking interactions between the phen ligands, as shown in
Supplementary Data
Fig. 3.
Thermogravimetric analysis of the complex was carried
out to examine its thermal stability. In the complex, the
first weight loss of 4.45% from 190 to 220 °C was attrib-
uted to the loss of water molecules from the complex
(calcd. 4.80%). Increasing the temperature to 355 °C led to
further decomposition, resulting in the second weight loss
CCDC 706400 contains the supplementary crystallographic
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.
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J Chem Crystallogr (2011) 41:143–146
Acknowledgments This research was supported by grants from the
Program for New Century Excellent Talents in University (NCET-
04-0987) and the Specialized Research Fund for the Doctoral
Program of Higher Education (No. 200507550033).
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