Hydrothermal synthesis and crystal structure of a complex with pyrogallic acid and N-donor ligand: 2-(4-methoxyphenyl)-1H-imidazo[4,5-f][1,10] phenanthroline

Article abstract of DOI:10.1080/15533174.2013.817422

The complex [Ni(MOPIP)₃(C₆H₅O ₃)]_n·nH₂O 1 (C₆H ₅O₃ = pyrogallic acid, MOPIP = 2-(4-methoxyphenyl)-1H- imidazo[4,5-f][1,10] phenanthroline) has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, TG, and single-crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic system, space group P 21/c, with α = 17.249 (3), b = 15.014 (3), c = 21.437 (4) A, β = 92.14 (3), V = 5547.7 (19) A³, and Z = 4 [at 293 (2) K]. In the crystal structure, the nickel atom is six coordinated with six nitrogen atoms from MOPIP ligand, showing a slightly distorted octahedral geometry. Furthermore, it exhibits a zero-dimensional (0D) structure with Ni-MOPIP as building units. The complex 1 extends 3D supramolecular structure through the hydrogen bonds and the π-π stacking interactions enhance the stability of the complex. Copyright

Full text of DOI:10.1080/15533174.2013.817422

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Synthesis and Reactivity in Inorganic, Metal-Organic,
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Hydrothermal Synthesis and Crystal Structure of a
Complex with Pyrogallic Acid and N-donor Ligand:
2-(4-methoxyphenyl)-1H-imidazo[4,5-f][1,10]
Phenanthroline
Yan-Ju Huanga, Yong-Sheng Yanb, Gang Duc & Yue Lianga
a Department of Chemistry, Tonghua Normal University, Tonghua, P.R. China
b School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, P.R. China
c Tonghua's NO.1 middle school, Tonghua, P.R. China
Accepted author version posted online: 11 Mar 2014.Published online: 02 Jun 2014.
To cite this article: Yan-Ju Huang, Yong-Sheng Yan, Gang Du & Yue Liang (2014) Hydrothermal Synthesis and Crystal Structure
of a Complex with Pyrogallic Acid and N-donor Ligand: 2-(4-methoxyphenyl)-1H-imidazo[4,5-f][1,10] Phenanthroline, Synthesis
and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 44:10, 1483-1486, DOI: 10.1080/15533174.2013.817422
To link to this article: http://dx.doi.org/10.1080/15533174.2013.817422
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Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 44:1483–1486, 2014
Copyright ꢀ Taylor & Francis Group, LLC
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ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533174.2013.817422
Hydrothermal Synthesis and Crystal Structure of a Complex
with Pyrogallic Acid and N-donor Ligand:
2-(4-methoxyphenyl)-1H-imidazo[4,5-f][1,10]
Phenanthroline
Yan-Ju Huang,1 Yong-Sheng Yan,2 Gang Du,3 and Yue Liang1
1 Department of Chemistry, Tonghua Normal University, Tonghua, P.R. China
2 School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, P.R. China
3 Tonghua’s NO.1 middle school, Tonghua, P.R. China
1920s, though still used by a few notable photographers. Pyro-
gallic acid had a reputation for erratic and unreliable behavior,
due possibly to its propensity for oxidation. So the complex of
pyrogallic acid is not very common.
The complex [Ni(MOPIP)3(C6H5O3)]n·nH2O 1 (C6H5O3
=
pyrogallic acid, MOPIP = 2-(4-methoxyphenyl)-1H-imidazo[4,5-
f][1,10] phenanthroline) has been hydrothermally synthesized and
structurally characterized by elemental analysis, IR spectrum, TG,
and single-crystal X-ray diffraction. Complex 1 crystallizes in the
monoclinic system, space group P 21/c, with a = 17.249 (3), b =
15.014 (3), c = 21.437 (4) Å, β = 92.14 (3), V = 5547.7 (19) Å3, and
Z = 4 [at 293 (2) K]. In the crystal structure, the nickel atom is six
coordinated with six nitrogen atoms from MOPIP ligand, showing
a slightly distorted octahedral geometry. Furthermore, it exhibits a
zero-dimensional (0D) structure with Ni-MOPIP as building units.
The complex 1 extends 3D supramolecular structure through the
hydrogen bonds and the π–π stacking interactions enhance the
stability of the complex.
Recently, 1,10-phenanthroline and its derivatives have shown
interesting properties, as they have two nitrogen donors, which
often act as chelating ligands due to their high affinity.[9–11]
2-(4-methoxyphenyl)-1H-imidazo[4,5-f][1,10] phenanthroline
(MOPIP) as a derivative of 1,10-phenanthroline and possessing
an extended aromatic system is a planar rigid bidentate chelating
reagent which can not only act as a terminal ligand but also po-
tentially provide supramolecular interactions such as aromatic
stacking to construct intriguing structures. For the past several
years, we have worked on the synthesis of 1,10-phenanthroline
and its derivatives ligand complexes.[12–15] However, the in-
vestigation for 1,10-phenanthroline and its derivative ligands
is not enough, especially MOPIP ligand and pyrogallic acid-
constructed metal–organic complexes have not been reported.
Based on the above reasons, we designed and synthesized of the
complex, namely: [Ni(MOPIP)3(C6H5O3)]n·nH2O 1.
Keywords complex, crystal structure, hydrothermal synthesis
INTRODUCTION
An important aspect of crystal engineering is to understand
and attempt to control the manner in which molecules are ar-
ranged in crystal lattices through the use of noncovalent in-
teractions such as electrostatic interactions, hydrogen bonding,
dispersion and induction forces, and π–π stacking interactions.
Two main approaches have emerged, namely, the use of hydro-
gen bonding interactions and the construction of polymeric co-
ordination networks, which are also referred to as metal–organic
frameworks.[1–8]
EXPERIMENTAL
Materials
The MOPIP ligand was synthesized according to the litera-
ture method.[14] Other chemicals from commercial sources were
of reagent grade and used without further purification.
Pyrogallic acid is popular on photographicin the 19th and
early 20th centuries, but, largely fell out of favor around the
Instruments and Measurements
Elemental analysis was carried out with a Perkin-Elmer 240C
analyzer; TG measurements were performed on a NETZSCH
STA 449C analyzer. The infrared (IR) spectrum was recorded
from KBr pellets in the range of 4000–400 cm−1 on a Nicolet
FT-IR 170SX spectrometer.
Received 29 April 2013; accepted 11 June 2013.
Address correspondence to Yan-Ju Huang, Department of Chem-
istry, Tonghua Normal University, Tonghua, 134002, P.R. China.
E-mail: huangyanju2007@163.com
Color versions of one or more of the figures in the article can be
found online at www.tandfonline.com/lsrt.
1483

1484
Y.-J. HUANG ET AL.
TABLE 1
Crystallographic data for the complex
Empirical formula
C66H48N12NiO7
Formula mass
Temperature (K)
Wavelength (Å)
Dc (g/cm3)
1179.87
293 (2)
0.71073
1.413
μ (MoKα) (mm−1
)
0.420
Crystal system
Space group
Monoclinic
P 21/c
Crystal size (mm)
a (Å)
0.16 × 0.15 × 0.13
17.249 (3)
b (Å)
15.014 (3)
c (Å)
21.437 (4)
β
92.14 (3)
Theta range for data collection
Limiting indices
2.34–25.00
−20< = h < = 14, −17 < =
k< = 15, −25 < = l < = 24
5547.7 (19)
FIG. 2. ORTEP drawing of 1 showing the local coordination. Environment of
Ni(II) with thermal ellipsoids at 30% probability.
V (Å3)
Z
4
R1, wR2 [I > 2σ(I)]
F (000)
0.0732, 0.1035
2448
25110 / 9710
1.207
diffractometer with a graphite-monochromatic MoKa radiation
(λ = 0.71073 Å) by using an φ–ω scan mode (4.68 ≤ 2θ ≤
50.00◦) at 293 (2) K. A total of 25,110 reflections were col-
lected and 9,710 were independent with Rint = 0.0732, of which
2,448 were observed with I > 2σ(I). The correction for Lp fac-
tors was applied. The structure was solved by direct methods
with SHELXS-97 program[16] and refined by SHELXL 97[17]
using full-matrix least-squares techniques on F2. All nonhy-
drogen atoms were refined anisotropically and hydrogen atoms
isotropically. All the hydrogen atoms were first found in dif-
ferent electron density maps, and then placed in the calculated
sites and included in the final refinement in the riding model
approximation with displacement parameters derived from the
Reflections collected /unique
Goodness-of-fit (GOF) on F2
Synthesis and Measurement
.
Complex 1 was prepared from a mixture of Ni(Ac)2 2H2O
(0.10 g), pyrogallic acid (0.08 g), MOPIP (0.12 g), and H2O
(16 mL) in a 30 mL Teflon-lined autoclave under autogenous
pressure at 180◦C for 6 days (Figure 1). After cooling to room
temperature, light-green block crystals of 1 were collected by
filtration and washed with distilled water in 54% yield (based on
Ni). Anal. Calcd. (%) for C66H48N12NiO7: C, 67.13; H, 4.07; N,
14.24. Found (%): C, 67. 09; H, 4.02; N, 14.39. IR (KBr, cm−1):
3401s (respectively, ascribed to the stretching vibrations of H2O,
which indicates the existence of water molecules), 1611s, 1505s,
1482s, 1409s, 1455m, 1354s, 1252m, 1188s, 1076s, 1027s,
731s.
TABLE 2
Selected bond lengths (Å) and angles (◦) for the complex
Bond
Dist.
Bond
Dist.
Ni(1)−N(1)
Ni(1)−N(5)
Ni(1)−N(9)
Angle
2.099 (8) Ni(1)−N(2)
2.060 (7) Ni(1)−N(6)
2.104 (8) Ni(1)−N(10)
2.091 (8)
2.091 (8)
2.085 (8)
(◦)
92.0 (3)
94.9 (3)
89.0 (3)
Crystal Structure Determination and Physical
Measurements
(◦)
Angle
A single crystal with dimensions of 0.16 mm × 0.15 mm ×
0.13 mm was mounted on a Rigaku Saturn 724+CCD X-ray
N(1)−Ni(1)−N(2)
79.4 (3) N(1)−Ni(1)−N(5)
N(1)−Ni(1)−N(6) 170.3 (3) N(1)−Ni(1)−N(9)
N(1)−Ni(1)−N(10) 97.1 (3) N(2)−Ni(1)−N(5)
O
N(2)−Ni(1)−N(6)
96.6 (3) N(2)−Ni(1)−N(9) 168.0 (3)
OH
N(2)−Ni(1)−N(10) 91.0 (3) N(5)−Ni(1)−N(6)
N(5)−Ni(1)−N(9) 101.9 (3) N(5)−Ni(1)−N(10) 170.8 (3)
N(6)−Ni(1)−N(9) 90.6 (3) N(6)−Ni(1)−N(10) 91.8 (3)
N(9)−Ni(1)−N(10) 79.0 (3)
79.1 (3)
.
Ni(Ac)2 2H2O
N
N
N
OH
OH
+
[Ni(MOPIP)3(C6H5O3)]n.nH2O
pH = 8.0
N
FIG. 1. The reaction equation of 1.

THE COMPLEX1 EXHIBITS ZERO-DIMENSIONAL STRUCTURE
1485
TABLE 3
Hydrogen bond lengths (Å) and angles (◦) for the complex
D–H···.A
d (D–H)
d (H···A)
d (D···A)
<(DHA)
O(4)−H(4A)···N(11)#1
O(5)−H(5A)···O(6)#2
N(8)−H(8B)···O(6)#3
C(22)−H(22A)···N(12)#4
C(60)−H(60A)···N(7)#5
N(4)−H(4B)···O(5)
0.82
0.82
0.86
0.93
0.96
0.86
0.86
0.85
0.82
0.93
0.93
0.93
0.93
0.93
0.93
1.93
1.92
1.75
2.41
2.60
2.14
2.36
2.05
2.40
2.58
2.36
2.58
2.55
2.57
2.62
2.730(11)
2.670(9)
164.6
152.1
159.8
151.9
153.7
157.0
124.3
170.9
108.9
100.3
158.6
102.5
168.9
100.3
116.5
2.573(11)
3.256(13)
3.483(18)
2.951(11)
2.931(11)
2.892(11)
2.777(10)
2.896(14)
3.243(13)
2.928(14)
3.463(14)
2.881(14)
3.148(13)
N(4)−H(4B)···O(4)
O(1W)−H(1WB)···N(12)
O(5)−H(5A)···O(6)
C(8)−H(8A)···N(3)
C(15)−H(15A)···O(5)
C(32)−H(32A)···N(8)
C(52)−H(52A)···O(1W)
C(52)−H(52A)···N(12)
C(57)−H(57A)···N(2)
Symmetry transformations used to generate equivalent atoms: #1, −x + 1, y + 1/2, −z + 1/2; #2, −x + 2, −y + 1, −z + 1; #3, −x + 2,
y−1/2, −z+1/2; #4, −x + 1, y−1/2, −z + 1/2; and #5, x−1, −y + 1/2, z−1/2.
parent atoms to which they were bonded. Further, the selected are one Ni(II) ion, three MOPIP ligands, one free water
important crystallographic data for the title complex are given molecule, and one free pyrogallic acid molecule in the sym-
in Table 1.
metric unit (Figure 2). The Ni(II) ion is hexa-coordinated with
six atoms [N(1), N(2), N(5), N(6), N(9), N(10)] from three dif-
ferent MOPIP ligands, assuming a slightly distorted octahedral
geometry. The Ni–N bond distances in the crystal are 2.060
(7) and 2.104 (8) Å, and close to the normal Ni–N distance is
2.0827 (5) Å which is comparable to those of 2.046 (3) and
2.055 (3) Å for Ni–N in the complex of [Ni(phen)(oba)]n·0.5
nH2O (phen = 1,10-phenanthroline).[18] The N−Ni−N angles
range from 79.0 (3) to 170.8 (3)◦. The selected important bond
parameters are given in Table 2. Hydrogen bonding interactions
are usually important in the synthesis of supramolecular ar-
chitectures.[19] There are persistent O−H···O, O(N)−H···N(O),
and C−HLO(N) hydrogen bonding interactions between crys-
tal molecules, free water molecules, and free pyrogallic acid
molecules (Table 3), which play an important role in stabilizing
the network structure and controlling the orientation of intrali-
gands. At the same time, aromatic ring of MOPIP ligand and
symmetry of the two adjacent equivalent of aromatic ring (sym-
metry codes: 1 − x, 1 − y, 1 − z, and x, 1/2 − y, −1/2 + z
and x, 1/2 − y, 1/2 + z) have π–π interactions with distance
between cg(4) → cg(10) ring centroids being 3.890(6) Å, cg(5)
→ cg(14) = 3.679 (6) Å, cg(14) → cg(5) = 3.680 (6) Å, cg(14)
→ cg(15) = 3.476 (6) Å, cg(15) → cg(14) = 3.477 (6) Å, and
cg(7) → cg(14) = 3.957 (6) Å [defined rings Cg(4): N3 → C5
→ C13 → N4 → C6, Cg(5): N7 → C25 → C33 → N8 →
C26, Cg(7): N1 → C1 → C2 → C3 → C4 → C18, Cg(9): N5
→ C21 → C22 → C23 → C24 → C38, Cg(10): N6 → C37
→ C36 → C35 → C34 → C39, Cg(14): C7 → C8 → C9 →
C10 → C11 → C12, and Cg(15): C24 → C25 → C33 → C34
RESULTS AND DISCUSSION
Description of Crystal Structures
Single-crystal X-ray diffraction analysis reveals that com-
plex [Ni(MOPIP)3(C6H5O3)]n·nH2O crystallizes in P21/c space
group and consists of a zero-dimensional (0D) structure. There
FIG. 3. View of 3D supramolecular framework in 1 showing hydrogen bonding
interactions and π–π interactions between the adjacent aromatic ring of MOPIP
ligand.

1486
Y.-J. HUANG ET AL.
CONCLUSIONS
Recently, 1,10-phenanthroline and its derivatives have shown
interesting properties for they have two nitrogen donors and
often act as chelating ligands due to their high affinity to
metal ions. However, pyrogallic acid had a reputation for
erratic and unreliable behavior, due to possibly its propen-
sity for oxidation. So the studies on the pyrogallic acid of
metal–organic complexes have rarely been reported. In this pa-
per, we have successfully synthesized a new metal–organic com-
plex [Ni(MOPIP)3(C6H5O3)]n·nH2O 1, with a 3D supramolec-
ular structure.
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Thermal Analysis
The stability of complex 1 was investigated by thermogravi-
metric analysis (Figure 4). The first weight loss of 6.52% for
1 is in the range from 38.3◦C to 175.3◦C corresponding to
the removal of free water molecules and part of the free py-
rogallic acid molecules (Calcd:1.53%–10.77%). Upon further
heating, an obvious weight loss (86.64%) occurs in the tem-
perature range of 175.3◦C to ∼ 673.4◦C, corresponding to
the release of MOPIP ligand and part of the free pyrogallic
acid molecules (Calcd: 82.90%–92.14%). After 673.4◦C, no
weight loss is observed, indicating the complete decomposition
of 1. The residual weight 6.84% (Calcd: 6.33%) corresponds to
NiO.