Synthesis and crystal structure of [Ni(H2O)6](C 19H17O9S)2?2H2O

Article abstract of DOI:10.1007/s10870-006-9074-8

A water soluble flavonoid sulfate, [Ni(H₂O)₆](C ₁₉H₁₇O₉S)₂?2H₂O was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. The crystal of it b

Full text of DOI:10.1007/s10870-006-9074-8

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Journal of Chemical Crystallography, Vol. 36, No. 8, August 2006 ( 2006)
DOI: 10.1007/s10870-006-9074-8
Synthesis and crystal structure of
[Ni(H2O)6](C19H17O9S)2·2H2O
Zun-Ting Zhang,(1)∗ Xue-Ling Zhang,(1) and Yun He Zhang(1)
Received September 29, 2005; accepted January 17, 2006
Published Online July 6, 2006
A water soluble flavonoid sulfate, [Ni(H2O)6](C19H17O9S)2·2H2O was synthesized and
its structure was determined by single-crystal X-ray diffraction analysis. The crystal of it
belongs to triclinic crystal system, space group P–1. The results show that the title compound
consists of [Ni(H2O)6]2+, C19H17O6SO3− and H2O. Ni(II) is located on the symmetry center
and octahedrally coordinated by six water molecules. A variety of hydrogen bonds among
[Ni(H2O)6]2+, C19H17O6SO3− and the lattice water molecules build a hydrophilic region.
Aromatic π–π stacking interactions assemble isoflavone skeletons into a column and the
columns form a hydrophobic region of the title compound. The sulfo-groups bridge the
hydrophilic regions and the hydrophobic regions as well as the inorganic components and
organic components. Hydrogen bonds, π · · · π stacking interactions and the electrostatic
interactions between cation [Ni(H2O)6]2+ and anion sulfonate C19H17O6SO3− lead the
moieties to a three-dimensional structure.
KEY WORDS: [Ni(H2O)6](C19H17O9S)2·2H2O; crystal structure; π–π stacking; hydrogen bond.
Introduction
vealed an enhancement of antioxidant activity as
compared with the parent flavonoids. Flavonoid
Flavonoids and related compounds are
sulfate occupies an important position in the field
of natural products chemistry since they provide
a structural link between organic and in-
organic components in nature.10 Irisolidone
(5,7-dihydroxy-6,4ꢁ-dimethoxyisoflavone), a kind
of flavonoid, had the most potent inhibitory
activity against Helicobacter pylori (HP)11
and reduced the ethanol-induced mortality as
well as serum alanine aminotransferase (ALT)
and aspartate aminotransferase (AST) activi-
ties.12–14 In this paper, irisolidone as leading
compound, a water soluble flavonoid sulfate
[Ni(H2O)6](C19H17O9S)2·2H2O (Scheme 1) was
known to exhibit a wide range of interest-
ing biological activities.1,2 Besides the extensive
biological activities of flavonoids, this class of
compounds exhibits antidiabetic3–5 and aldose re-
ductase inhibitory activity.6 Because the solubility
of flavonoid is poor, its biological utilization rate
is low. Thus, it is necessary to synthesize a water
soluble derivative of flavonoid in order to study its
possible biological effects. Our previous works7–9
found the solubility of flavonoid sulfates is better
and the pharmacological assay of them has re-
1
(1) School of Chemistry and Materials Science, ShaanXi Normal
University, Xi’An 710062 People’s Republic of China.
synthesized. Its structure was elucidated by H
NMR, IR spectroscopic techniques and X-ray sin-
gle crystal diffraction.
∗
To whom correspondence should be addressed; e-mail: zhangzt@
snnu.edu.cn.
517
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1074-1542/06/0800-0517/0 2006 Springer Science+Business Media, Inc.

518
Zhang, Zhang, and Zhang
-
2+
1
O
8
OH2
Ni
H3CO
H3CO
2
H2O
H2O
OH2
7
A
C
2'
B
5'
3'
1'
2H O
2
·
SO3
2
·
3
6
4
5
OH2
4'
6'
OCH3 O
OH2
OCH3
Scheme 1.
Experimental
1H NMR (DMSO-d6, 300 MHz, ppm) δ: 3.77
–
–
(s, 3H, CH3O C6), 3.79 (s, 6H, CH3O C7 and
ꢁ
The chemicals and solvents used in this work
were of analytical grade available commercially
and were used without further purification. The
infrared spectrum was recorded as KBr pellets on
a Nicollet 170SX FT-IR spectrophotometer. The
melting point was determined using X4 melting
point instrument (the thermometer had not been
emended). The 1H NMR spectrum was recorded
on a Bruker AM-300 spectrometer with TMS as
internal reference and DMSO-d6 as solvent. The
crystal structure was determined with a Bruker
Smart-1000 CCD Diffractometer instrument.
Irisolidone (2.0 g) was dissolved into ace-
tone (60 mL) and KOH (2 mL, 0.3%). Dimethyl
sulfate (2 mL) was added dropwise to the solution
with vigorous stirring. The mixture was stirred
at room temperature for 8 h. The solution was
poured into water (60 mL), pale yellow precip-
itation appeared which was filtered and washed
with water until the pH of the filtrate was 7. The
resulting solid residue (1.8 g) was slowly added to
the concentrated sulfuric acid (9 mL), the mixture
was stirred at 40◦C for 30 min and poured into
the saturated NaCl solution (40 mL) to obtain
another yellow precipitate. After 2 h, the precipi-
tate was filtered and washed with saturated NaCl
solution until the pH value of the filtrate was 7.
It was dissolved in water (20 mL), mixed with
saturated NiCl2·6H2O solution (10 mL). Crys-
tals of the title compound were obtained after
one week at room temperature, which were re-
crystallized from ethanol-water (V:V = 1:1) solu-
tion to give green prismatic crystals, m.p.: 584
K (decomposed). IR (KBr) ν: 3447, 1645, 1598,
1489, 1258, 1191, 1091, 828, 631, 550, 489 cm−1.
–
–
CH3O C4 ), 3.93 (s, 3H, CH3O C5), 7.00 (s, 1H,
ꢁ
–
–
H C8), 7.03 (d, 1H, J = 5.4 Hz, H C5 ), 7.44 (dd,
ꢁ
–
1H, J = 8.5 Hz, J = 2.0 Hz, H C6 ), 7.84 (d, 1H,
ꢁ
–
–
J = 2.0 Hz, H C2 ), 8.25 (s, 1H, H C2).
A single crystal with dimensions of
0.39 mm × 0.36 mm × 0.17 mm was chosen for
Table 1. Crystal Data and Structure Refinement for the Title
Compound
CCDC no
284891
Empirical formula
Formula weight
Temperature (K)
C38 H50 Ni O26 S2
1045.61
298(2)
0.71073
Triclinic
P–1
˚
Wavelength (A)
Crystal system
Space group
Unit cell dimensions
˚
a (A)
8.3518(16)
11.402(2)
˚
b (A)
˚
c (A)
13.432(3)
α
β
γ
66.676(3)◦
80.337(3)◦
73.289(3)◦
3
˚
Volume (A )
1122.8(4)
Z, Calculated density (mg m−3
Absorption coefficient (mm−1
F(000)
Crystal size (mm)
θ range for data collection (◦)
Limiting indices
)
1, 1.546
)
0.619
546
0.39 × 0.36 × 0.17
2.01–28.41
− 11 ≤ h ≤ 10, − 14 ≤ k ≤ 9,
− 17 ≤ l ≤ 17
Reflections collected/unique
Absorption correction
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness Of fit on F2
Final R indices [I > 2σ (I)]
R indices (all data)
Largest diff. peak and hole
7368/5197 [Rint = 0.0142]
Semi empirical from equivalents
0.9021 and 0.7944
Full-matrix least squares on F2
5197/12/339
1.007
R1 = 0.0383, wR2 = 0.0984
R1 = 0.0535, wR2 = 0.1097
0.492 and − 0.359
(eA−3
)

Synthesis and crystal structure
519
X-ray diffraction (XRD) studies. The data were
Results and discussion
collected with graphite-monochromated Mo Kα
radiation (λ = 0.71073 A) on a Bruker Smart-
˚
The title compound consists of a complex
cation [Ni(H2O)6]2+, two anions of isoflavone
sulfonate C19H17O6SO3− and two lattice wa-
ter molecules (Fig. 1). Ni(II) lies on an in-
version center and is coordinated by six water
molecules which form a slightly distorted oc-
tahedron, in which the average bond length of
1000 CCD diffractometer at room temperature.
The structure was solved by direct methods
and refined on F2 by full matrix least-squares
with the Bruker’s SHELXL-97 program.15 All
non-hydrogen atoms were refined anisotropically.
All hydrogen atoms were treated using a riding
model. The crystals used for the diffraction study
showed no decomposition during data collection.
The refinement converged to final R = 0.0383,
wR = 0.0984. Data collection detail and structure
determination results are summarized in Table 1.
Selected bond lengths and angles are presented in
Table 2.
−
˚
–
Ni O is 2.055 A. The anion C19H17O6SO3 is
composed of a benzopyranone moiety, includ-
–
–
ing rings A (C4 C9) and C (O1/C9/C1 C4),
–
a phenyl moiety B (C10 C15), four methoxyl
groups and a sulfo-group. The atoms of ben-
zopyranone moiety are nearly coplanar, the di-
–
hedral angle between ring A (C4 C9) and ring
◦
˚
Table 2. Selected Bond Lengths (A) and Angles ( ) for the Title Compound
–
–
Ni(1) O(12)
2.0351(16) Ni(1) O(10)
2.0572(15)
1.343(2)
1.235(2)
1.373(3)
1.351(2)
1.4585(17)
0.858(16)
0.860(16)
1.777(2)
0.9300
–
–
2.0744(16) O(1) C(1)
Ni(1) O(11)
–
–
O(2) C(3)
–
O(4) C(6)
–
O(6) C(13)
O(1) C(9)
1.375(2)
1.376(2)
1.345(3)
–
O(3) C(5)
–
O(5) C(7)
–
–
1.4458(15) O(9) S(1)
–
0.826(16) O(11) H(23)
–
0.833(16) O(12) H(25)
–
0.900(14) S(1) C(12)
O(7) S(1)
–
O(10) H(21)
–
O(11) H(24)
–
O(13) H(27)
–
–
C(1) H(1)
C(1) C(2)
1.346(3)
1.466(3)
1.382(3)
0.9300
–
–
C(2) C(3)
C(4) C(9)
1.397(3)
1.413(3)
1.392(3)
0.9600
–
–
C(6) C(7)
–
C(10) C(11)
–
C(16) H(16A)
C(5) C(6)
–
C(8) H(8)
–
C(12) C(13)
1.403(3)
–
–
–
–
–
–
–
O(12) Ni(1) O(12)
180.0
O(12) Ni(1) O(10)
90.69(6)
87.21(7)
91.23(7)
118.43(16)
117.99(19)
107(2)
–
– –
O(12) Ni(1) O(11)
– –
O(10) Ni(1) O(11)
– –
C(1) O(1) C(9)
– –
C(13) O(6) C(19)
O(12) Ni(1) O(11)
92.79(7)
88.77(7)
180.00(9)
114.83(18)
115(2)
–
O(10) Ni(1) O(11)
–
O(11) Ni(1) O(11)
–
–
C(5) O(3) C(16)
–
–
– –
H(21) O(10) H(22)
Ni(1) O(10) H(21)
–
–
–
–
–
Ni(1) O(11) H(23)
118.6(18)
126(2)
H(23) O(11) H(24)
104.0(19)
87.6(17)
108.40(9)
118.57(18)
120.89(19)
120.5(2)
119.99(19)
114.12(17)
117.34(19)
121.38(19)
120.39(19)
124.7(2)
119.6
–
– –
H(27) O(13) H(28)
– –
O(7) S(1) C(12)
– –
C(1) C(2) C(3)
– –
C(6) C(5) C(4)
– –
C(5) C(6) C(7)
– –
C(8) C(7) C(6)
– –
O(1) C(9) C(8)
– –
C(11) C(10) C(15)
– –
C(12) C(11) C(10)
– –
C(11) C(12) C(13)
– –
O(6) C(13) C(14)
– –
C(15) C(14) H(14)
Ni(1) O(12) H(26)
–
–
–
–
–
–
–
–
O(7) S(1) O(8)
112.72(10)
125.84(19)
115.90(18)
120.4(2)
124.4(2)
120.9
124.47(19)
121.03(19)
119.3
–
O(1) C(1) C(2)
–
C(9) C(4) C(5)
–
O(4) C(6) C(5)
–
O(5) C(7) C(8)
–
C(9) C(8) H(8)
–
C(8) C(9) C(4)
–
–
–
–
–
C(15) C(10) C(2)
–
C(10) C(11) H(11)
–
C(11) C(12) S(1)
118.27(16)
120.7(2)
109.5
–
C(15) C(14) C(13)
–
–
–
–
O(3) C(16) H(16A)
H(16A) C(16) H(16B)
109.5

520
Zhang, Zhang, and Zhang
Fig. 1. Molecular structure of the title compound showing 30% probability
–
displacement ellipsoids. Thin dashed lines indicate O H· · ·O hydrogen bonds.
◦
–
–
–
C (O1/C9/C1 C4) is 4.8 To avoid steric con-
for O10 H22· · ·O2, O11 H24· · ·O2. The combi-
nation of them generates aR22(6) ring. The oxygen
atom of sulfo-group also forms tricenterd hydro-
gen bond with lattice water molecule and coordi-
nated water molecule, which can be observed for
flicts, the two rigid ring systems, phenyl ring B
–
(C10 C15) and benzopyranone moiety are ro-
tated by 37.1◦ with respect to each other. The
methoxyl groups at atom C7 and C13 are nearly
coplanar with their attached rings, as indi◦cated
–
–
O12 H26· · ·O8, O13 H28· · ·O8. The methoxyl
–
–
–
by the torsion angle C8 C7 O5 C18 = 8.5 and
group and the coordinated water molecule are
◦
–
–
–
–
C14 C13 O6 C19 = 1.7 . The methoxyl groups
linked by the hydrogen bond O11 H24· · ·O3.
at atom C5 and C6 are almost vertical with
the benzopyranone moiety, indicative of the
◦
◦
˚
Table 3. Typical Hydrogen Bond Lengths (A) and Angles ( ) for
–
–
–
torsion angle C4 C5 O3 C16 = − 105.6 and
◦
the Title Compound
–
–
–
–
C5 C6 O4 C17 = 90.6 The similar S O bond
lengths and bond angles involving O7, O8, and
O9 show that the negative charge is delocal-
ized over the three oxygen atoms.10 As shown in
–
–
D H
–
D H· · ·A
H· · ·A D· · ·A D H· · ·A
–
O10 H21· · ·O7@
0.826
0.833
0.858
0.833
0.833
0.860
0.824
0.900
0.924
0.930
1.928
1.921
1.846
2.117
2.536
1.902
2.066
2.638
2.034
2.477
2.754
2.737
2.700
2.848
3.234
2.754
2.857
3.537
2.927
3.381
176.69
165.93
173.08
146.25
142.09
170.87
160.74
176.64
162.16
164.18
–
O10 H22· · ·O2
–
Fig. 1, the sulfo-group( SO3), methoxyl group,
–
O11 H23· · ·O13#
carbonyl group, two lattice water molecules and
six coordinated water molecules are linked by the
–
O11 H24· · ·O2
–
O11 H24· · ·O3
–
O12 H25· · ·O9#
–
O H· · ·O hydrogen bonds (The typical hydrogen
–
O12 H26· · ·O8
bond lengths and angles are given in Table 3). The
carbonyl oxygen atom accepts protons from the
coordinated water molecules to form tricenterd
hydrogen bond, O2 acts as an acceptor, via H22
and H24 to O10 and O11, which can be observed
–
O13 H27· · ·O5&
–
O13 H28· · ·O8
–
C8 H8· · ·O7$
Symmetry code: @ x − 1, y, z; # − x + 1, − y + 1, − z + 1; &
x + 1, y − 1, z + 1; $ 1 − x, 1 − y, − z.

Synthesis and crystal structure
521
Fig. 2. Part of crystal structure of the title compound, showing
π–π stacking interactions and hydrogen bonds. For clarity,
some H atoms have been omitted. Symmetry code: ∗ − x,
1 − y, − z; $ 1 − x, 1 − y, − z.
Fig. 3. Unit-cell packing diagram of the title compound.
These hydrogen bonds not only link the isoflavone
skeletons, coordinated water molecules and lattice
water molecules, but also play an important role
in the formation, stability and crystallization of
the title compound.
In the crystal structure of title compound,
the hydrogen bonds among sulfo-group, car-
bonyl, methoxyl group of the isoflavone skele-
ton, lattice water molecules and coordinated wa-
ter molecules, the π–π stacking interactions of
isoflavone skeletons and the electrostatic interac-
tions between the cation and the anion assem-
ble the moieties into supramolecule with a three-
dimensional structure. It is interesting that the title
compound has a special configuration (Fig. 3). A
hydrophilic metal region is formed among lattice
water molecules, coordinated water molecules,
sulfo-group, methoxyl group and carbonyl via
hydrogen bonds network. Apart from the hydro-
gen bonds involved in the molecular structure,
The isoflavone skeletons of title compound
are stacked into a hydrophobic column as dis-
played in Fig. 2. Two adjacent molecules form a
π–π interaction dimer by a completely antiparal-
leled manner between rings C with the interplanar
˚
distance of 3.485 A, the offset distance of 1.021
∗
˚
˚
–
A and CgC CgC = 3.631 A, where CgC and
CgC∗ are the centroids of ring C of the adjacent
isoflavone skeletons at (x, y, z) and ( − x, 1 − y,
− z), respectively. The ring-centroid distance lies
16
˚
–
in the normal range of 3.3 3.8 A, indicative of
–
π–π stacking interactions. The dimmer interacts
with the other via paired intermolecular hydrogen
the hydrogen bond O11 H23· · ·O13# [Symmetry
code: # ( − x + 1, − y + 1, − z + 1)] exists be-
2
–
bonds C8 H8· · ·O7 which form a R2 (22) ring.
tween the coordinated water and the lattice
–
–
For the hydrogen bond C8 H8· · ·O7$ [Symmetry
water molecule. O13 H27· · ·O5& [Symmetry
code: $ (1 − x, 1 − y, − z)], atom O7 acted as
code: & (x + 1, y − 1, z + 1)] occurs between
hydrogen-bond acceptor, via atom H8 to C8, the
the lattice water molecule and the sulfo-group.
˚
–
distances of C8· · ·O7 and H8· · ·O7 are 3.381 A
O10 H21· · ·O7@ [Symmetry code: @ (x − 1, y,
˚
–
–
and 2.447 A, the bond angle C8 H8· · ·O7 being
z)] and O12 H25· · ·O9# are all hydrogen bonds
164.1◦ Combination of the aromatic π–π stack-
between the coordinated water molecules and the
sulfo-group. Combination of the hydrogen bonds
generates the hydrophilic region of the title com-
pound. On the other side, a column is formed
–
ing interactions and the “soft” C H· · ·O hydrogen
bonds generates the hydrophobic columns along
a-axis.

522
Zhang, Zhang, and Zhang
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Supplementary material CCDC-284891 contains the supplemen-
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