Supramolecular pseudometallacycles in a nickel compound with 4,4-diaminodiphenylmethane: Synthesis and structure of {Ni[(CH 2(C6H4NH2)2] 2(NO3)2(H2O)2}

Article abstract of DOI:10.1134/S0036023608110089

The [Ni(DDM)₂(NO₃)₂(H₂O) ₂] complex (DDM is 4,4-diaminodiphenylmethane [CH₂(C ₆H₄NH₂)₂]) is synthesized, and its structure is determined. The crystals are triclinic, space group P 1?, a = 5.846(1) ?, b = 9.450(2) ?, c = 13.390(3) ?, α = 105.63(3)°, β = 98.13(3)°, γ = 105.84(3)°, V = 666.6(2) ?³, ρ_calcd = 1.553 g/cm³, Z = 2. The Ni(II) ion (in the inversion center) is bound to a distorted octahedral array formed by the nitrogen atoms of the primary amino groups of the DDM molecules and the oxygen atoms of the monodentate nitrato groups and water molecules (Ni(1)-N(3) 2.119(2) ?, Ni(1)-O(1) 2.122(2) ?, Ni(1)-O(w) 2.047(2) ?, angles at the Ni atoms vary in the 85.08(9)°-94.92(9)° interval). The structure contains supramolecular metallacycles formed by the O(w)-H? N(2) hydrogen bonds between the coordinated H₂O molecules and the terminal amino groups of DDM. The metallacycles are joined by the Ni²⁺ ions into infinite chains running in the [111] direction.

Full text of DOI:10.1134/S0036023608110089

ISSN 0036-0236, Russian Journal of Inorganic Chemistry, 2008, Vol. 53, No. 11, pp. 1718–1723. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © Yu.V. Kokunov, V.V. Kovalev, Yu.E. Gorbunova, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 11, pp. 1838–1843.
COORDINATION
COMPOUNDS
Supramolecular Pseudometallacycles in a Nickel Compound
with 4,4-Diaminodiphenylmethane: Synthesis and Structure
of {Ni[(CH2(C6H4NH2)2]2(NO3)2(H2O)2}
Yu. V. Kokunov, V. V. Kovalev, and Yu. E. Gorbunova
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
Received October 23, 2007
Abstract—The [Ni(DDM)2(NO3)2(H2O)2] complex (DDM is 4,4-diaminodiphenylmethane [CH2(C6H4NH2)2])
is synthesized, and its structure is determined. The crystals are triclinic, space group P 1, a = 5.846(1) Å, b =
9.450(2) Å, c = 13.390(3) Å, α = 105.63(3)°, β = 98.13(3)°, γ = 105.84(3)°, V = 666.6(2) Å3, ρcalcd = 1.553 g/cm3,
Z = 2. The Ni(II) ion (in the inversion center) is bound to a distorted octahedral array formed by the nitrogen
atoms of the primary amino groups of the DDM molecules and the oxygen atoms of the monodentate nitrato
groups and water molecules (Ni(1)–N(3) 2.119(2) Å, Ni(1)–O(1) 2.122(2) Å, Ni(1)–O(w) 2.047(2) Å, angles
at the Ni atoms vary in the 85.08(9)°–94.92(9)° interval). The structure contains supramolecular metallacycles
formed by the O(w)–H···N(2) hydrogen bonds between the coordinated H2O molecules and the terminal amino
groups of DDM. The metallacycles are joined by the Ni2+ ions into infinite chains running in the [111] direction.
DOI: 10.1134/S0036023608110089
Increased interest in the design and assembly of
This work is aimed at synthesizing and studying the
supramolecular architectures is due to their new structure of the coordination nickel polymer with the
unusual topology and a possibility of wide practical use nonrigid ditopic nitrogen-containing ligand 4,4-diami-
[1–4]. Inorganic–organic hybrid coordination polymers nodiphenylmethane CH2(C6H4NH2)2 (DDM).
are synthesized using polyfunctional organic ligands in
order to bind transition metal ions due to the self-
EXPERIMENTAL
assembly resulting in compounds of various architec-
tures. This requires careful choice of multidentate
ligands to efficienty assist the formation of the corre-
sponding polymeric structures. Pyrazine and bipyridine
and their analogues are usually used as bridging ligands,
whereas various amines (aromatic and aliphatic) are used
more rarely. For example, coordination polymers of silver
based on aminomethylpyridines [5, 6] and di- and triami-
nocyclohexane [7] are known. We recently synthesized
and structurally characterized the coordination polymer of
silver {Ag[(CH2(C6H4NH2)2]2(CH3C6H4NH2)V2}NO3
[8] with the 4,4-diaminodiphenylmethane bridging ligand.
Synthesis. To synthesize [Ni(DDM)2(NO3)2(H2O)2]
(I), Ni(NO3)2 · 6H2O (pure for analysis) and DDM
(Merck) were used. Acetonitrile was purified by distil-
lation over P2O5, and dimethylformamide (DMF) was
distilled under reduced pressure in the presence of
CaH2.
Dimethylformamide was added dropwise with stir-
ring to a mixture of nickel nitrate (0.40 g, 1.37 mmol)
and 4,4-diaminodiphenylmethane (0.82 g, 4.13 mmol)
in MeCN (10 mL) until the salt dissolved completely,
and the solution was kept for several days. The crystals
that precipitated (dark green in bulk) were separated
from the mother liquor, washed with a minimal amount
of MeCN, and dried in air at room temperature. The
yield was 73%. The crystals were examined using ele-
mental analysis, NMR, IR spectroscopy, and X-ray dif-
fraction.
In the design of coordination polymers and
supramolecular assemblies of bivalent metal com-
pounds, the Co(II), Zn(II), and Cd(II) derivatives are
used most actively, whereas Ni(II) is less often applied
[9, 10].
As a rule, an octahedral environment is formed
around the Ni2+ ion. Four or two coordination sites
should be blocked to obtain its coordination polymers
(1D chains and 2D layers, respectively) involving
ditopic nitrogen-containing ligands. Chelating or
strongly coordinating monodentate ligands are used for
this purpose [10–14].
For C13H16N3Ni0.5O4 anal. calcd. (%): N, 13.65;
C, 50.71; H, 5.20.
Found (%): N, 13.21; C, 51.01; H, 5.08.
When the synthesis was carried out with an equimo-
lar ratio of the reactants, the composition of the isolated
1718

SUPRAMOLECULAR PSEUDOMETALLACYCLES IN A NICKEL COMPOUND
1719
Table 1. Crystallographic data and selected experimental
details for structure I
crystals did not differ from the above composition
(according to the elemental analysis data).
IR absorption spectra were recorded as Nujol
mulls on a Specord 75 IR spectrophotometer in the
range 4000–400 cm–1.
FW
307.64
0.15 × 0.23 × 0.68
Triclinic
Crystal size, mm
Crystal system
X-ray diffraction analysis. An experimental mate-
rial for the crystals of compound I was obtained on an
Enraf-Nonius CAD-4 automated diffractometer.
Absorption correction was applied empirically accord-
ing to the North–Phillips algorithm using two Ψ scan
curves. The structure was solved by the heavy-atom
method and refined by the least-squares method in the
full-matrix anisotropic approximation for all non-
hydrogen atoms. Hydrogen atoms were introduced in
geometrically calculated positions and refined as riding
on their bond atoms with fixed isotropic temperature
parameter (Uiso = 0.08 Å2). The H atoms of the water
molecules were found from a difference Fourier syn-
thesis. All calculations were performed using the
SHELXS86 and SHELXL93 program packages.
Space group
P1
Cell parameters:
a, Å
5.846(1)
9.450(2)
13.390(3)
105.63(3)
98.13(3)
105.84(3)
666.6(2)
2
b, Å
c, Å
α, deg
β, deg
γ, deg
V, Å3
Z
ρ
µ
calcd, g/cm3
Mo, mm–1
1.533
0.790
The crystallographic data and selected experimental
details for structure I are given in Table 1. The coordi-
nates of atoms and their temperature factors are pre-
sented in Table 2. Selected bond lengths and bond
angles are listed in Table 3. The hydrogen bond geom-
etry is given in Table 4.
F(000)
322
T, K
293
Radiation (λ, Å)
Mo Kα (0.71073),
graphite monochromator
Scan type
ω
θ range, deg
Index ranges
1.62–29.97
–8 ≤ h ≤ 1, –13 ≤ k ≤ 13,
RESULTS AND DISCUSSION
–18 ≤ l ≤ 18
The IR spectrum of compound I shows five bands at
3377–3165 cm–1, i.e., in the region where bands of
symmetric and asymmetric stretching vibrations of the
NH2 groups appear. The spectrum of compound I is
more complicated than that of free DDM due to such
factors as the presence of water molecules in the com-
plex, the nonequivalent character of the amino groups
of the ditopic ligand, and, most likely, hydrogen bond-
ing. A significant difference between the spectra of the
Total number of reflections
2855
Number of observed reflections
with I ≥ 2σ(I)
Number of refined parameters
GOOF on F2
2215 [R(int) = 0.0185]
188
0.452
R [I ≥ 2σ(I)]
R1 = 0.0340,
wR2 = 0.0930
Extinction coefficient
0.000(4)
complex and free DDM is observed in the long-wave- Residual electron density
0.363/–0.260
(max/min), e/Å3
length region as well. It is known [15] that primary
amines should produce absorption at longer wave-
lengths caused by external bending vibrations of the
(by ~70 cm–1) for the bidentate coordination. Note that
the band at 1300 cm–1, unlike two other bands, almost
coincides with that appeared in the IR spectrum of free
DDM.
The structure of molecule I is shown in Fig. 1. The
coordination polyhedron of the Ni atom (in the inver-
sion center) is a distorted octahedron formed by the
symmetrically bound nitrogen atoms of the primary
amino groups of the monodentate DDM ligand and
oxygen atoms of the nitrato groups and water mole-
cules. The distances are Ni(1)–N(3), 2.119(2); Ni(1)–
O(1), 2.122(2); and Ni(1)–O(w), 2.047(2) Å; and the
angles at the Ni atom vary within 85.08(9)°– 94.92(9)°.
NH2 groups. Although this phenomenon is poorly stud-
ied, most primary amines give rise to a broad band at
650–900 cm–1, which is attributed to this type of vibra-
tions. The spectrum of free DDM also shows a broad
strong band at 620 cm–1, which can be attributed to
δ(NH2). This band is strongly shifted to the high-fre-
quency region (by ~200 cm–1), which is probably due to
the nonequivalence of the NH2 groups. The three stron-
gest bands at 1427, 1301, and 1040 cm–1 (the latter is
split into two components) correspond to, respectively,
νas(NO2), νs(NO2), and ν(NO) of the monodentate NO3
groups. This assignment agrees entirely with the results
of the detailed study of the nickel complexes with dif-
ferently bound nitrate groups [16], including the value
∆ = νas – νs, which is, as a rule, significantly higher
Note that the terminal nitrogen atoms of DDM par-
ticipate in the O(w)–H···N(2) hydrogen bonds as proton
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 53 No. 11 2008

1720
KOKUNOV et al.
Table 2. Atomic coordinates and temperature factors (Ueq =
1/3ΣUij) for structure I
angle between their planes is 101.9°. The monodentate
planar nitrato groups NO3 participate through the termi-
nal oxygen atoms in hydrogen bonding with the H2O
molecules and with the nitrogen atoms of DDM
(Table 4) as proton acceptors to stabilize the structure.
Note that the involvement of the Ni2+ ion in the coor-
dination of the water molecules and NO–3 anions, along
with the DDM molecules, results in the saturation of its
coordination sphere and the formation of only
supramolecular rings that form original chains. In the
silver coordination polymer [8], rather rare octahedral
coordination of Ag+ ions due to the primary amino
groups of the DDM ligands and p-toluidine is observed
and the 2D polymer forms from conjugated many-
membered metallacycles with the bridging DDM
ligands. The NO–3 anion exists in the outer sphere.
It is likely that noncoordinating anions (for exam-
ple, PF–6, BF–4 should be used in the presence of water
Atom
x
y
z
Ueq, Å2
Ni(1)
N(1)
N(2)
N(3)
O(1)
O(2)
O(3)
O(w)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
0
0
0
0.027(1)
0.2763(4) 0.0473(3) –0.1706(2) 0.035(1)
–0.8505(5) –0.7172(3) –0.6773(2) 0.045(1)
0.0930(4) –0.1948(2) 0.0180(2) 0.036(1)
0.2922(4) 0.0336(3) –0.0782(2) 0.043(1)
0.4028(5) –0.0069(3) –0.2269(2) 0.059(1)
0.1410(4) 0.1126(3) –0.2022(2) 0.057(1)
0.2593(3) 0.1294(2) 0.1381(1) 0.035(1)
–0.3726(5) –0.7574(3) –0.4263(2) 0.033(1)
–0.2137(5) –0.4446(3) –0.0916(2) 0.034(1)
–0.1221(5) –0.6177(3) –0.2388(2) 0.030(1)
–0.2834(5) –0.5819(3) –0.1764(2) 0.034(1)
0.0205(5) –0.3393(3) –0.0682(2) 0.030(1)
0.1116(5) –0.5117(3) –0.2125(2) 0.035(1)
0.1827(5) –0.3731(3) –0.1283(2) 0.035(1)
–0.6917(5) –0.7307(3) –0.5925(2) 0.035(1)
–0.2028(5) –0.7653(3) –0.3333(2) 0.038(1)
molecules to obtain a coordination polymer of nickel
with such a ditopic nitrogen-containing ligand as
DDM.
In bivalent metal compounds, both coordination and
hydrogen bonds are involved in the two- and three-
dimensional networks from metal-containing building
blocks. Both types of bonding are pertinent since they
exert directed effect. When metal centers are bound by
rigid ligands (for instance, bipyridine and others), rigid
networks are formed, whereas nonrigid supramolecular
structures are formed when weaker hydrogen bonds are
involved in binding. For example, in the [Cu(3,5-
PDC)(H2O)2] compound (3,5-PDC is pyridine-3,5-
dicarboxylate) [17] the supramolecular three-dimen-
sional coordination polymer is formed due to joining
the adjacent layers through the hydrogen bonds
between the coordinated water molecules and bifunc-
tional carboxylate groups. The [Co(3,5-PDC)(H2O)5] ·
2H2O structure [18] is composed of discrete molecules
in which the Co2+ ion is coordinated to the vertices of
an octahedron formed by five oxygen atoms of the
water molecules and the nitrogen atom of the 3,5-PDC
ligand, whereas the noncoordinated carboxy groups of
3,5-PDC are involved in intermolecular hydrogen
bonding with the coordinated water molecules to form
a supramolecular two-dimensional cyclic network. As
an example we can present a silver compound
[Ag2(CF3COO)2(PIP)4] (PIP is piperazine) [19] in which
the Ag2(CF3COO)2 dimers are linked by N−H···O hydro-
gen bonds to form a unique two-dimensional network
consisting of the rhomboid supramolecular rings.
C(10) –0.6220(5) –0.8350(3) –0.4504(2) 0.040(1)
C(11) –0.2855(5) –0.6685(3) –0.4887(2) 0.038(1)
C(12) –0.4417(6) –0.6546(3) –0.5706(2) 0.041(1)
C(13) –0.7796(5) –0.8220(3) –0.5327(2) 0.041(1)
H(2A) –0.789
H(2B) –1.013
–0.660
–0.766
–0.217
–0.164
–0.423
–0.654
–0.535
–0.301
–0.784
–0.851
–0.899
–0.615
–0.593
–0.877
0.183
–0.717
–0.692
0.072
H(3A)
H(3B)
0.033
0.257
0.039
H(2C) –0.327
H(4A) –0.446
–0.492
–0.193
–0.253
–0.112
–0.355
–0.312
–0.410
–0.474
–0.613
–0.548
0.201
H(6A)
H(7A)
0.227
0.345
H(9A) –0.061
H(9B) –0.285
H(10A) –0.686
H(11A) –0.113
H(12A) –0.377
H(13A) –0.952
H(1)
H(2)
0.220
0.363
0.089
0.161
acceptors, resulting in the formation of the supramolec-
ular rings. Each cycle includes two Ni2+ ions, two DDM
ligands, and two water molecules. The rings share the Ni2+
ions to form infinite chains extended in the [111] direction
(Fig. 2). The Ni···Ni distance in the ring is 13.5 Å. The
In structure I, the DDM ligand plays a dual role: one
NH2 group forms the donor-acceptor bond with the Ni2+
ion, whereas the second, noncoordinated NH2 group
acts as a proton acceptor in the H-bond with the H2O
molecule that coordinates the adjacent Ni atom. As a
aromatic rings in DDM are planar, and the dihedral result, the supramolecular rings producing unique
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 53 No. 11 2008

SUPRAMOLECULAR PSEUDOMETALLACYCLES IN A NICKEL COMPOUND
Table 3. Bond lengths (d) and bond angles (ω) in structure I
1721
Bond
d, Å
Bond
d, Å
Ni(1)–O(w)
Ni(1)–N(3)
Ni(1)–O(1)
N(1)–O(3)
N(1)–O(2)
N(1)–O(1)
N(2)–C(8)
N(3)–C(5)
C(1)–C(10)
C(1)–C(11)
C(1)–C(9)
2.047(2)
2.119(2)
2.122(2)
1.225(3)
1.238(3)
1.271(3)
1.418(3)
1.440(3)
1.387(4)
1.388(4)
1.512(3)
C(2)–C(4)
C(2)–C(5)
C(3)–C(6)
C(3)–C(4)
C(3)–C(9)
C(5)–C(7)
C(6)–C(7)
C(8)–C(13)
C(8)–C(12)
C(10)–C(13)
C(11)–C(12)
1.388(4)
1.389(4)
1.386(4)
1.395(4)
1.513(3)
1.375(4)
1.390(4)
1.378(4)
1.389(4)
1.388(4)
1.383(4)
Angle
ω, deg
Angle
ω, deg
O(w)Ni(1)N(3)
O(w)Ni(1)N(3)
N(3)Ni(1)O(1)
O(3)N(1)O(2)
O(3)N(1)O(1)
O(2)N(1)O(1)
C(5)N(3)Ni(1)
N(1)O(1)Ni(1)
C(10)C(1)C(11)
C(10)C(1)C(9)
C(11)C(1)C(9)
C(4)C(2)C(5)
C(6)C(3)C(4)
C(6)C(3)C(9)
C(4)C(3)C(9)
86.81(8)
85.97 (8)
85.08(9)
121.4(2)
120.8(2)
117.8(2)
121.9(2)
125.1(2)
117.7(2)
121.1(2)
121.2(2)
119.8(2)
117.6(2)
121.5 (2)
120.9 (2)
C(2)C(4)C(3)
C(7)C(5)C(2)
C(7)C(5)N(3)
C(2)C(5)N(3)
C(3)C(6)C(7)
C(5)C(7)C(6)
C(13)C(8)C(12)
C(13)C(8)N(2)
C(12)C(8)N(2)
C(1)C(9)C(3)
C(1)C(10)C(13)
C(12)C(11)C(1)
C(11)C(12)C(8)
C(8)C(13)C(10)
121.4 (2)
119.7 (2)
120.0(2)
120.2(2)
121.5(2)
120.0(2)
118.8(2)
121.2(3)
120.0(2)
112.3(2)
121.2(3)
121.4(3)
120.3(2)
120.6(3)
Table 4. Hydrogen bonding geometry in structure I
…
…
…
B
Bond A–H
…
B
Position of atom B
A
A–H
H
B
Angle AHB, deg
O(w)–H(1) N(2)
1 + x, 1 + y, 1 + z
1 – x, –y, –z
2.765(3)
2.826(3)
2.765(3)
3.361(4)
3.010(3)
3.446(4)
0.95
0.86
0.90
0.90
0.90
0.90
1.82
1.97
2.49
2.52
2.27
2.50
179
175
98
…
O(w)–H(2) O(2)
…
N(2)–H(2A) O(W) –1 + x, –1 + y, –1 + z
…
N(2)–H(2B) O(2) –1 – x, –1 – y, –1 – z
156
139
167
…
N(3)–H(3A) O(3) –x, –y, –z
…
N(3)–H(3B) O(2) 1 – x, –y, –z
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 53 No. 11 2008

1722
KOKUNOV et al.
C(10)
C(13)
C(8)
C(9)
C(3)
C(4)
N(2)
C(1)
C(11)
C(12)
C(6)
C(7)
C(2)
C(5) N(3)
Ni(1)
O(2)
O(3)
N(1)
O(1)
O(w)
Fig. 1. Structure of molecule I.
0
x
z
y
Fig. 2. Fragment of structure I: the chains of the supramolecular rings extended in the [111] direction.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 53 No. 11 2008

SUPRAMOLECULAR PSEUDOMETALLACYCLES IN A NICKEL COMPOUND
1723
8. Yu. V. Kokunov, V. V. Kovalev, and Yu. E. Gorbunova,
Zh. Neorg. Khim. 52 (12) (2007) [Russ. J. Inorg. Chem.
52 (12), 1877 (2007)].
chains are formed from the [Ni(DDM)2(H2O)2(NO3)2]
building units.
9. L.-M. Duan, F.-T. Xie, and X.-Y. Chen, et al., Cryst.
Growth Design 6 (5), 1101 (2006).
ACKNOWLEDGMENTS
This work was supported by the Russian Foundation
for Basic Research (project no. 06-03-32460) and the
Presidium of the Russian Academy of Sciences (Pro-
gram for Basic Research “Development of Methods for
Synthesis of Chemical Substances and Design of New
Materials”).
10. K. Biradha, A. Mondal, B. Moulton, and M. J. Zaworotko,
J. Chem. Soc., Dalton Trans., No. 21, 3837 (2000).
11. O. M.Yaghi, H. Li, and T. L. Groy, Inorg. Chem. 36 (20),
4292 (1997).
12. K. Biradha, K. V. Domasevitch, and B. Moulton, et al.,
J. Chem. Soc., Chem. Commun., No. 14, 1327 (1999).
13. K. Biradha and M. Fujita, J. Chem. Soc., Dalton Trans.,
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