Low-temperature (100 K) crystal structures of pentaaqua(5-nitrosalicylato) complexes of magnesium(II), zinc(II), cobalt(II) and nickel(II): A π-π stacked and hydrogen bonded 3D supramolecular architecture

Article abstract of DOI:10.1016/j.poly.2006.01.018

Reactions of metal chloride or sulfate and the sodium salt of 5-nitrosalicylic acid (5-nsa) in aqueous solution result in isomorphous complexes of type [M(H₂O)₅(5-nsa)]⁺ (5-nsa)^- · H₂O [M = Mg (1), Zn (2), Co (3), Ni (4)] in the solid state. Structural analyses of these compounds reveal that the cationic moiety is a monomeric complex in which the metal is coordinated by five aqua ligands and one carboxylato O-atom from the 5-nitrosalicylato ligand, forming a slightly distorted octahedron. The crystal packing exhibits ionic parts assembled through extensive hydrogen bonding. The metal-bonded cationic moiety and the non-ligating anionic one are also engaged in π-stacking interactions which contribute to the crystal cohesion. The anchoring of the individual ionic subunits through π-π stacking and hydrogen bonding results in a 3D supramolecular architecture.

Full text of DOI:10.1016/j.poly.2006.01.018

Polyhedron 25 (2006) 2229–2235
www.elsevier.com/locate/poly
Low-temperature (100 K) crystal structures of
pentaaqua(5-nitrosalicylato) complexes of magnesium(II),
zinc(II), cobalt(II) and nickel(II): A p–p stacked and hydrogen
bonded 3D supramolecular architecture
a,
b
c
Georges Morgant *, Nouzha Bouhmaida , Lamine Balde ,
Nour Eddine Ghermani d,e, Jean d’Angelo
a
a
b
c
ˆ
Biocis, UMR CNRS 8076, Faculte´ de Pharmacie, Universite´ Paris-Sud, 5 rue J.-B. Cle´ment, 92296 Chatenay-Malabry, France
Laboratoire des Sciences des Mate´riaux, Faculte´ des Sciences Semlalia, Universite´ Cadi-Ayyad, BP 2390, Marrakech, Morocco
Laboratoire de Chimie-Physique, Mine´rale et Bioinorganique, Faculte´ de Pharmacie, Universite´ Paris-Sud, 5 rue J.-B. Cle´ment,
ˆ
92296 Chatenay-Malabry, France
Laboratoire Structures, Proprie´te´s et Mode´lisation des Solides (SPMS), UMR CNRS 8580, Ecole Centrale Paris, Grande Voie des Vignes,
d
ˆ
92295 Chatenay-Malabry, France
Laboratoire Physico-Chimie, Pharmacotechnie, Biopharmacie (PPB), UMR CNRS 8612, Faculte´ de Pharmacie, Universite´ Paris-Sud,
e
ˆ
5 rue J.-B. Cle´ment, 92296 Chatenay-Malabry, France
Received 15 December 2005; accepted 25 January 2006
Available online 10 March 2006
Abstract
Reactions of metal chloride or sulfate and the sodium salt of 5-nitrosalicylic acid (5-nsa) in aqueous solution result in isomorphous
complexes of type [M(H2O)5(5-nsa)]+ (5-nsa)À Æ H2O [M = Mg (1), Zn (2), Co (3), Ni (4)] in the solid state. Structural analyses of these
compounds reveal that the cationic moiety is a monomeric complex in which the metal is coordinated by five aqua ligands and one carb-
oxylato O-atom from the 5-nitrosalicylato ligand, forming a slightly distorted octahedron. The crystal packing exhibits ionic parts assem-
bled through extensive hydrogen bonding. The metal-bonded cationic moiety and the non-ligating anionic one are also engaged in
p-stacking interactions which contribute to the crystal cohesion. The anchoring of the individual ionic subunits through p–p stacking
and hydrogen bonding results in a 3D supramolecular architecture.
ꢀ 2006 Elsevier Ltd. All rights reserved.
Keywords: Crystal structure; Mg(II), Zn(II), Co(II) and Ni(II) complexes; 5-Nitrosalicylic acid ligand; p–p Stacking; Hydrogen bonded 3D supra-
molecular architecture
1. Introduction
significance has been the demonstration that zinc(II) and
copper(II) complexes of salicylic acid [2k,2n], 3,5-diisopro-
pylsalicylic acid [2f,2h,2j,2n] and aspirin [2l,2n] are more
effective anticonvulsants than their parent ligands in ani-
mal models of epilepsy. As part of a systematic program
devoted to the study of structure–activity relationships of
(salicylato) metal complexes, herein we report the crystal
structures of (5-nitrosalicylato) complexes of Mg(II), Zn(II),
Co(II) and Ni(II). Since the 5-nitrosalicylic acid ligand (5-
nsa) used in the present study is notably more acidic than
parent salicylic acid (pKa’s: 2.1 versus 3.0), its affinity for
Since the report by Sorenson that the anti-inflammatory
and anti-rheumatoid activities of aspirin (acetylsalicylic
acid) are notably enhanced upon Cu(II) complexation [1],
the coordination chemistry of (salicylato) metal complexes
has received considerable attention [2]. Also of peculiar
*
Corresponding author. Tel.: +33 146835463.
E-mail address: georges.morgant@cep.u-psud.fr (G. Morgant).
0277-5387/$ - see front matter ꢀ 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2006.01.018

2230
G. Morgant et al. / Polyhedron 25 (2006) 2229–2235
metal cations and therefore the biological activities of its
metal complexes should be significantly altered. The most
salient feature of these isomorphous crystal structures is
that the individual ionic subunits self-assemble via p–p
stacking and extensive intermolecular hydrogen bonding,
resulting in a 3D supramolecular architecture.
J = 9.3, 2.6 Hz, 1H, H-4), 6.99 (d, J = 9.3 Hz, 1H, H-3).
IR (neat, cmÀ1): 3407(m), 1623(m), 1588(s), 1503(m),
1475(s), 1447(s), 1386(s), 1333(s), 1287(s), 1151(s),
1074(m), 926(m), 888(m), 844(m), 807(m), 750(m), 710(m),
640(m).
2.3.3. [Co(H2O)5(5-nsa)]+(5-nsa)À Æ H2O (3)
2. Experimental
Sodium 5-nitrosalicylate was prepared by neutralizing
5-nitrosalicylic acid (0.915 g, 5 mmol) with 5 ml of 1 M
NaOH. To this solution was added CoSO4 Æ 7H2O
(0.702 g, 2.5 mmol) in 3 ml of water. After a few days 3
was filtered, crystallized in water and dried over calcium
chloride. Yield: 0.888 g (67%). Anal. Calc. for
C14H20N2O16Co (3): C, 31.65; H, 3.80; N, 5.27. Found:
C, 31.46; H, 3.91; N, 5.16%. Thermal study (TG-DTA)
reveals a weight loss of 20.2% (Calc. 20.3%) at 75–
165 ꢁC, corresponding to loss of six crystalline water mol-
ecules (both crystallization and coordination water). IR
(neat, cmÀ1): 3403(m), 1624(m), 1589(s), 1503(m),
1475(s), 1448(s), 1386(m), 1332(s), 1288(s), 1150(s),
1073(m), 926(m), 895(m), 843(m), 808(m), 750(m),
710(m), 698(m), 640(m).
2.1. Materials
High purity 5-nitrosalicylic acid, anhydrous magnesium
chloride, zinc sulfate heptahydrate, cobalt sulfate heptahy-
drate and nickel chloride hexahydrate were purchased from
Acros (USA) and used without further purification.
2.2. Physical measurement
Elemental analyses (C, H and N) were performed on a
Perkin–Elmer 2400 analyzer. Thermal analysis (TG-
DTA) was carried out using a TGA7 Perkin–Elmer ther-
mal analyzer under N2. The 1H NMR spectra were
recorded with Bruker AC 200 P (200 MHz) spectrometer;
the chemical shifts are expressed in terms of ppm. The IR
spectra were recorded with Bruker Vector 22 spectrometer.
2.3.4. [Ni(H2O)5(5-nsa)]+(5-nsa)À Æ H2O (4)
Sodium 5-nitrosalicylate was prepared by neutralizing
5-nitrosalicylic acid (0.915 g, 5 mmol) with 5 ml of 1 M
NaOH. To this solution was added NiCl2 Æ 6H2O
(0.594 g, 2.5 mmol) in 3 ml of water. After a few days 4
was filtered, crystallized in water and dried over calcium
chloride. Yield: 0.887 g (67%). Anal. Calc. for
C14H20N2O16Ni (4): C, 31.66; H, 3.80; N, 5.27. Found:
C, 31.44; H, 3.75; N, 5.14%. Thermal study (TG-DTA)
reveals a weight loss of 20.1% (Calc. 20.3%) at 70–
190 ꢁC, corresponding to loss of six crystalline water mol-
ecules (both crystallization and coordination water). IR
(neat, cmÀ1): 3406(m), 1624(m), 1589(s), 1503(m),
1475(s), 1448(s), 1386(s), 1332(s), 1287(s), 1151(s),
1074(m), 927(m), 890(m), 844(m), 809(m), 750(m), 710(s),
697(s), 640(m).
2.3. Preparation of the complexes
2.3.1. [Mg(H2O)5(5-nsa)]+(5-nsa)À Æ H2O (1)
Sodium 5-nitrosalicylate was prepared by neutralizing
5-nitrosalicylic acid (0.915 g, 5 mmol) with 5 ml of 1 M
NaOH. To this solution was added anhydrous MgCl2
(0.238 g, 2.5 mmol) in 3 ml of water. After a few days 1
was filtered, crystallized in water and dried over calcium
chloride. Yield: 0.620 g (64%). Anal. Calc. for
C14H20N2O16Mg (1): C, 33.85; H, 4.07; N, 5.64. Found:
C, 33.60; H, 3.96; N, 5.55%. Thermal study (TG-DTA)
reveals a weight loss of 20.5% (Calc. 21.7%) at 75–
230 ꢁC, corresponding approximately to loss of six crystal-
line water molecules (both crystallization and coordination
water). IR (neat, cmÀ1): 3423(m), 1624(m), 1590(s),
1475(s), 1450(s), 1386(m), 1332(s), 1150(s), 1074(m),
926(m), 842(m), 808(m), 751(m), 698(s), 639(m).
2.4. X-ray diffraction study
Diffraction data were collected on a Bruker-SMART
three axis diffractometer equipped with a SMART 1000
CCD area detector using graphite monochromated
2.3.2. [Zn(H2O)5(5-nsa)]+(5-nsa)À Æ H2O (2)
˚
Sodium 5-nitrosalicylate was prepared by neutralizing
5-nitrosalicylic acid (0.915 g, 5 mmol) with 5 ml of 1 M
NaOH. To this solution was added ZnSO4 Æ 7H2O
(0.720 g, 2.5 mmol) in 3 ml of water. After a few days 2
was filtered, crystallized in water and dried over calcium
chloride. Yield: 1.076 g (80%). Anal. Calc. for
C14H20N2O16Zn (2): C, 31.27; H, 3.76; N, 5.21. Found: C,
31.16; H, 3.99; N, 5.25%. Thermal study (TG-DTA) reveals
a weight loss of 19.7% (Calc. 20.1%) at 55–160 ꢁC, corre-
sponding to loss of six crystalline water molecules (both
Mo Ka X-radiation (wavelength k = 0.71073 A) at
100.0(1) K. The low temperature was reached by an evap-
orated liquid nitrogen stream over the crystal, provided
by the Oxford Cryosystem device. Data collection and pro-
cessing were carried out using Bruker SMART programs [3]
and empirical absorption correction was applied using
SADABS computer program [3]. The structure was solved
by direct methods SIR97 [4], and refined by full-matrix
least-squares based on F using CRYSTALS software [5]. All
non-hydrogen atoms were anisotropically refined. The
hydrogen atoms were located in difference Fourier maps.
H atoms were refined isotropically with Uiso = 1.20 Ueq
1
crystallization and coordination water). H NMR (D2O,
200 MHz) d: 8.62 (d, J = 2.6 Hz, 1H, H-6), 8.24 (dd,

G. Morgant et al. / Polyhedron 25 (2006) 2229–2235
2231
where Ueq is the equivalent isotropic atomic displacement
OH2
OH2
H2O
H2O
parameter of the attached atom. The crystal parameters,
data collection and the refinement details of compounds
1, 2, 3 and 4 are reported in Table 1.
Ni
NO2
O
H2O
NO2
. H2O
HO
O
O
O
3. Results and discussion
HO
The structure determinations show that all these com-
plexes are isomorphous and crystallize in Pna21 ortho-
rhombic space group. The asymmetric unit can be
represented by the general formula: [M1(H2O)5(5-nsa)]+
(5-nsa)À Æ H2O where M1 = magnesium, zinc, cobalt or
nickel. Since complexes 1–4 are isomorphous, no notable
differences were observed between their structural parame-
ters. For that reason, only the details of the X-ray structure
of Ni(II) complex (4), arbitrarily chosen, were reported and
discussed in the present paper. The canonical drawing and
the CAMERON [6] molecular structure of the Ni(II) com-
plex (4) are represented in Figs. 1 and 2, respectively, with
the atom numbering system used in Table 2, which lists the
most relevant bond distances and angles.
Fig. 1. Canonical representation of [Ni(H2O)5(5-nsa)]+(5-nsa)À Æ H2O (4).
ligand, forming a slightly distorted octahedron. The cis
angles around the Ni center vary between 86.13(6)ꢁ and
94.32(7)ꢁ while the trans angles vary from 173.22(6)ꢁ to
˚
176.29(7)ꢁ. The Ni–O(36) distance [2.026(2) A] is notably
shorter than those for Ni–O(10), Ni–O(11), Ni–O(12),
Ni–O(13), Ni–O(14), [2.040(2), 2.095(2), 2.086(2),
˚
2.067(2), 2.043(2) A, respectively]. These bonds are proba-
bly quite dependent on the H-bonding system, which is
very important in this structure. The presence of six water
molecules leads to a very extensive and complicated H-
bonding network. All the aqua ligands and the solvate
water molecule form strong H-bonds between themselves,
with the carboxylato O-atoms, the nitro O-atoms and the
phenoxo O-atoms. A list of the most probable atoms
involved in H-bonds with their related angles is given in
Table 3. Fig. 3 shows the H-bonding association in the
asymmetric unit. The H-bonds are extended in all directions
The structure of [Ni(H2O)5(5-nsa)]+(5-nsa)À Æ H2O (4)
consists of one [Ni(H2O)5(5-nsa)]+ cation, one (5-nsa)À
serves as a counter-anion and one water molecule exists
as solvate molecule. The cation is a monomeric complex
in which Ni(II) is coordinated to five aqua ligands and
the carboxylato O(36)-atom from the 5-nitrosalicylato
Table 1
Crystal data and structure refinement parameters for C14H20N2O16M1 (M1 = Mg, Zn, Co or Ni)
Compound
1
2
3
4
Empirical formula
Molecular weight
Color
Crystal system
Space group
C
496.62
ocher
orthorhombic
Pna21
14H20N2O16Mg
C14H20N2O16Zn
537.70
yellow
orthorhombic
Pna21
C14H20N2O16Co
531.25
salmon pink
orthorhombic
Pna21
C14H20N2O16Ni
531.03
greenish
orthorhombic
Pna21
˚
a (A)
18.081(5)
15.736(5)
7.151(5)
90
90
90
2034 (2)
4
1.621
18.085(5)
15.720(5)
7.137(5)
90
90
90
2029 (2)
4
1.760
18.081(5)
15.736(5)
7.151(5)
90
90
90
2034 (2)
4
1.734
17.996(5)
15.688(5)
7.142(5)
90
90
90
2016 (2)
4
1.749
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
Calculated density (g cmÀ3
Absorption coefficient (mmÀ1
)
)
0.176
1.300
0.932
1.052
F(000)
1032
1104
1092
1096
Crystal size (mm3)
h Ranges (ꢁ)
h/k/l
0.17 · 0.22 · 0.27
1.72–29.96
0,25/0,21/À9,10
100
0.18 · 0.22 · 0.25
1.72–29.72
0,25/0,21/À9,9
100
0.17 · 0.22 · 0.28
1.72–29.96
0,24/0,21/À9,9
100
0.16 · 0.20 · 0.25
1.72–29.98
0,25/0,22/À10,9
100
T (K)
Number of reflections collected
Number of independent reflections
Number of reflections used P 3r(I)
Parameters
14381
5126
3927
299
14293
5129
4502
300
14628
5149
3829
299
14586
4839
3155
300
R [F]
wR [F]
0.0285
0.0335
1.0731
À0.24; 0.30
0.0006
0.0218
0.0237
1.1184
0.0228
0.0247
1.1265
0.0210
0.0221
1.1448
Goodness-of-fit on F À3
˚
Residual density (e A
Refine ls shift/su.max
)
À0.34; 0.44
À0.50; 0.31
À0.49; 0.50
0.0014
0.0005
0.0013

2232
G. Morgant et al. / Polyhedron 25 (2006) 2229–2235
Table 3
+
H-bond donor/acceptor scheme (A, ꢁ) for [Ni(H2O)5(5-nsa)] (5-nsa)À Æ
˚
H2O (4)
O10
O14
D–HÁ Á ÁA
d(D–H)
D(HÁ Á ÁA)
\(DHA)
O(21)–H(21)Á Á ÁO(27)
O(31)–H(31)Á Á ÁO(37)
O(12)–H(122)Á Á ÁO(37)
O(13)–H(132)Á Á ÁO(21)
O(200)–H(201)Á Á ÁO(26)
O(13)–H(131)Á Á ÁO(200)i
O(10)–H(102)Á Á ÁO(26)i
O(11)–H(111)Á Á ÁO(31)i
O(14)–H(141)Á Á ÁO(27)i
O(10)–H(101)Á Á ÁO(200)ii
O(12)–H(121)Á Á ÁO(26)ii
O(200)–H(202)Á Á ÁO(12)iii
O(14)–H(142)Á Á ÁO(25)iv
O(11)–H(112)Á Á ÁO(34)iv
0.8723(2)
0.8227(2)
0.8322(2)
0.8682(2)
0.8045(2)
0.8852(4)
0.9007(4)
0.7232(2)
0.9227(2)
0.8459(2)
0.8245(2)
0.8276(4)
0.8621(3)
0.8852(3)
1.649(2)
1.744(2)
1.811(2)
1.939(2)
1.969(2)
1.860(3)
1.930(2)
2.167(2)
1.755(2)
1.841(2)
2.027(2)
2.128(3)
1.958(2)
2.299(3)
156.33(7)
155.89(7)
162.64(8)
175.16(8)
159.09(6)
176.04(8)
175.46(6)
172.27(6)
169.98(7)
176.99(8)
165.28(7)
140.03(7)
163.39(7)
161.54(7)
O11
Ni1
O13
O25
C23
C24
O12
C22
O21
O36
C21
N24
O34
C36
C20 C25
C35
C30
O24
O37
N34
O35
O27
C34
C31
Symmetry codes: i, x À 1/2, Ày + 3/2, z; ii, Àx + 3/2, y + 1/2, z + 1/2;
C26
O26
iii, x + 1/2, Ày + 3/2, z À 1; iv, Àx + 1, Ày + 1, z + 1/2.
C33
O31
C32
O200
Fig. 2. Labeled CAMERON diagram of [Ni(H2O)5(5-nsa)]+(5-nsa)À Æ
H2O (4). Ellipsoids are drawn at 50% probability level.
forming a H-bonded 3D network, as illustrated in Fig. 4.
The crystal cohesion is thus ensured by fourteen hydrogen
bonds per asymmetric unit: three intramolecular, two inter-
Table 2
+
˚
Selected bond distances (A) and bond angles (ꢁ) for [Ni(H2O)5(5-nsa)] -
(5-nsa)À Æ H2O (4)
Bond lengths
Ni–O(14)
Ni–O(12)
Ni–O(10)
2.043(2)
2.086(2)
2.040(2)
Ni–O(11)
Ni–O(13)
Ni–O(36)
2.095(2)
2.067(2)
2.026(2)
Non-ligating aromatic moiety
Metal-bonded aromatic moiety
O(21)–C(21)
O(24)–N(24)
O(25)–N(24)
O(26)–C(26)
O(27)–C(26)
C(20)–C(21)
C(21)–C(22)
C(22)–C(23)
C(23)–C(24)
C(24)–C(25)
C(25)–C(20)
C(20)–C(26)
C(24)–N(24)
1.343(2)
O(31)–C(31)
O(34)–N(34)
O(35)–N(34)
O(36)–C(36)
O(37)–C(36)
C(30)–C(31)
C(31)–C(32)
C(32)–C(33)
C(33)–C(34)
C(34)–C(35)
C(35)–C(30)
C(30)–C(36)
C(34)–N(34)
1.342(3)
1.228(3)
1.241(3)
1.256(3)
1.274(3)
1.420(3)
1.396(3)
1.385(3)
1.392(3)
1.381(3)
1.396(3)
1.493(3)
1.446(3)
1.241(3)
1.221(3)
1.252(3)
1.277(3)
1.412(3)
1.410(3)
1.376(3)
1.392(3)
1.390(3)
1.396(3)
1.505(3)
1.460(3)
Fig. 3. Labeled diagram of [Ni(H2O)5(5-nsa)]+(5-nsa)À Æ H2O (4) showing
the H-bonding associations as broken lines [Symmetry codes: i, x À 1/2,
Ày + 3/2, z; ii, Àx + 3/2, y + 1/2, z + 1/2; iii, x + 1/2, Ày + 3/2, z À 1;
iv, Àx+ 1, Ày + 1, z + 1/2.].
Bond angles
molecular intra-asymmetric unit and nine intermolecular
inter-asymmetric unit (Figs. 3 and 4).
O(14)–Ni–O(12)
O(11)–Ni–O(13)
O(10)–Ni–O(36)
O(14)–Ni–O(10)
O(12)–Ni–O(10)
O(14)–Ni–O(11)
O(12)–Ni–O(11)
O(10)–Ni–O(11)
176.29(7)
175.43(7)
173.22(6)
89.17(7)
92.20(7)
94.32(7)
89.21(8)
86.13(6)
O(14)–Ni–O(13)
O(12)–Ni–O(13)
O(10)–Ni–O(13)
O(14)–Ni–O(36)
O(12)–Ni–O(36)
O(11)–Ni–O(36)
O(13)–Ni–O(36)
Ni–O(36)–C(36)
89.02(8)
87.51(7)
90.80(7)
86.36(7)
92.57(7)
89.12(7)
94.21(7)
127.8(2)
In both aromatic units, the 5-nitro group is roughly
coplanar with the adjacent phenyl ring [torsion angle
C(23)–C(24)–N(24)–O(24): 174.13ꢁ (non-ligating aromatic
moiety); torsion angle C(33)–C(34)–N(34)–O(34): 174.36ꢁ
(metal-bonded aromatic moiety)]. However, a notable dis-
symmetry was observed between the N–O lengths of each

G. Morgant et al. / Polyhedron 25 (2006) 2229–2235
2233
˚
˚
[C(26)–O(26): 1.256(3) A, C(26)–O(27): 1.274(3) A;
c
˚
˚
C(36)–O(37): 1.277(3) A, C(36)–O(36): 1.252(3) A]. This
dissymmetry is typical of asymmetrically-bonded (uniden-
tate) carboxylato ligands, and is seen in the crystal struc-
ture of a variety of (salicylato) metal complexes [2e,2f].
Another salient geometrical feature of this structure is
that the non-ligating 5-nsa moiety [C(20) to C(25) plane,
denoted P(1)] and the metal-bonded one [C(30) to C(35)
plane, denoted P(2)] are pairwise linked by p–p stacking
interactions (Figs. 5 and 6). Remarkably, this stacking
implicates a syn-facial arrangement of the aromatic nuclei
(superimposition of the same faces); in sharp contrast,
Smith and co-workers have observed an anti-facial
arrangement of the p-bonded 5-nsa ligands (superimposi-
tion of the opposite faces) in the proton-transfer com-
pounds with a variety of Lewis bases [7]. The dihedral
angle between mean planes P(1) and P(2) is 5.86(6)ꢁ.
b
0
The two 5-nsa rings have
a
centroid separation
˚
CgP(1). . .CgP(2) of 3.847 A and a mean interplanar spac-
˚
ing of 3.400 A [orthogonal projection of CgP(2) on P(1)]
a
˚
corresponding to a ring-centroid offset of 1.800 A (Table
Fig. 4. Perspective diagram of packing of [Ni(H2O)5(5-nsa)]+(5-nsa)À Æ
H2O (4) in the unit cell showing the extensive 3D H-bonded network
(dashed lines). Ni centers are symbolized by large gray tone circles.
4). Although this offset is quite large, a notable p-overlap-
ping exists between the two aromatic nuclei (Fig. 5). On
the other hand, the metal-bonded nucleus is slightly
rotated counterclockwise around C(32)–C(35) axis (by
ca. 1ꢁ) relatively to the non-ligating nucleus plane, as
highlighted in Fig. 6. Besides the anchoring of the
metal-bonded cationic moiety to the non-ligating anionic
counterpart through p–p interaction, these are connected
by two types of intermolecular hydrogen bonds: seven
inter-asymmetric unit bonds [O(26)i. . .H(102)–O(10)–Ni,
O(26)iiÁ Á ÁH(121)–O(12)–Ni, O(200)iiÁ Á ÁH(101)–O(10)–Ni,
O(200)iÁ Á ÁH(131)–O(13)–Ni, H(202)Á Á ÁO(12)iii–Ni, O(27)iÁ Á Á
H(141)–O(14)–Ni, O(25)ivÁ Á ÁH(142)–O(14)–Ni] and one
intra-asymmetric unit bond [O(21)Á Á ÁH(132)–O(13)–Ni]
(Fig. 3).
˚
aromatic moiety [N(24)–O(24): 1.228(3) A, N(24)–O(25):
1.241(3) A; N(34)–O(34): 1.241(3) A, N(34)–O(35):
1.221(3) A]. This can be rationalized by invoking that
˚
˚
˚
O(25) and O(34) are both implicated in intermolecular
hydrogen bonds [with H(142) and H(112), respectively],
Fig. 3. Similarly, the carboxylate group of each aromatic
unit is essentially coplanar with the adjacent phenyl ring
[torsion angle C(21)–C(20)–C(26)–O(26): 178.48ꢁ (non-
ligating aromatic moiety); torsion angle C(31)–C(30)–
C(36)–O(36): 176.95ꢁ (metal-bonded aromatic moiety)]
with a marked dissymmetry between the C–O lengths
O34
O35
N34
O25
N24
O24
C23
C35
O11
O14
O36
C20
C32
O10
Ni1
O26
O37
O31
O13
O21
O27
O12
O200
Fig. 5. Perspective diagram of [Ni(H2O)5(5-nsa)]+(5-nsa)À Æ H2O (4) with labeled heteroatoms and some representative carbon atoms concentrating on the
p–p stack viewed perpendicularly to the plane of the non-ligating aromatic nucleus.

2234
G. Morgant et al. / Polyhedron 25 (2006) 2229–2235
O11
O12
Ni1
O10
O14
O13
O200
Fig. 6. Perspective diagram of [Ni(H2O)5(5-nsa)]+(5-nsa)À Æ H2O (4) focusing on the edges of the p–p stacked aromatic nuclei viewed in the plane of the
non-ligating nucleus.
Table 4
in connection with the elaboration of potent (salicylato)
metal complexes-based drugs. Secondly, the original
metallo-organic framework of these complexes consisting
Structural details of the p-stacking interactions in [Ni(H2O)5(5-nsa)]+-
(5-nsa)À Æ H2O (4)
Distance from C(35)
to P(1) (A)
Distance from C(30)
to P(1) (A)
Distance from C(34)
to P(1) (A)
Distance from C(31)
to P(1) (A)
Distance from C(33)
to P(1) (A)
Distance from C(32)
to P(1) (A)
3.261(3)
3.300(3)
3.368(3)
3.428(3)
3.545(3)
3.547(3)
Dihedral angle between
P(1) and P(2) (ꢁ)
Ring-centroid
separation (A)
Mean interplanar
spacinga (A)
˚
5.86(6)
3.847
3.400
1.800
of cationic/anionic aromatic moieties linked together
through p-stacking and hydrogen bonding might be of
peculiar interest in the design of functional materials.
For instance, the p–p stacking interactions have been uti-
lized in several research areas such as molecular conduc-
tors [8] and electronics [9]. In other respects, since the
five shortest separations between Ni centers in 4 are
˚
˚
˚
˚
Ring-centroid
˚
˚
offset (A)
˚
6.78, 7.14, 9.25, 10.66 and 11.76 A, long-range magnetic
˚
interactions are expected, which could be exploited to
elaborate molecular-based magnetic materials [10].
˚
a
Orthogonal projection of the metal-bonded nucleus centroid on the
non-ligating nucleus plane.
5. Supplementary data
Crystallographic data for the structures reported in this
paper have been deposited with the Cambridge Crystallo-
graphic Data Center as supplementary publication Nos.
CCDC 286184 (3) – CCDC 286185 (1) – CCDC 28186
(4) – CCDC 28187 (2). Copies of this information can be
obtained free of charge from The Director, CCDC, 12,
Union Road, Cambridge CB2 1EZ, UK (fax: +44 1223
336033; e-mail: deposit@ccdc.cam.ac.uk or http://
www.ccdc.cam.ac.uk).
4. Conclusion
We have shown that the individual ionic subunits of
the 5-nsa complexes with Mg(II), Zn(II), Co(II) and
Ni(II) self-assemble via p–p stacking and extensive hydro-
gen bonding involving water molecules, leading to a 3D
supramolecular architecture. The propensity for the 5-
nsa ligand to be paired via p–p stacking interaction,
already reported by Smith and co-workers [7], is notewor-
thy. In sharp contrast, the isomorphous 4-nsa complexes
Acknowledgements
of Zn(II), Co(II) and Ni(II) reported par Ulku and co-
¨
workers [2e], regioisomers of complexes 2, 3 and 4, respec-
tively, consist of centrosymmetric monomers with the
metal atom occupying the two inversion centers at 0,0,0
and 0,1/2,1/2 of a monoclinic unit cell. This work is
being continued in two directions. First, the biological
activities of complexes 1–4 are currently under evaluation
This paper is dedicated to Professor John R.J. Sorenson
(University of Arkansas, USA). Financial support of
´
Universite Paris XI, CNRS and Ecole Centrale Paris is
gratefully acknowledged. The authors thank Mrs. S.
Mairesse-Lebrun for performing elemental analyses and
Mr. M. Sghaier for performing DTA analyses.

G. Morgant et al. / Polyhedron 25 (2006) 2229–2235
2235
(m) H. Icbudak, H. Olmez, O.Z. Yesilel, F. Arslan, P. Naumov, G.
Jovanovski, A.R. Ibrahim, A. Usman, H.-K. Fun, S. Chant-
rapromma, S.W. Ng, J. Mol. Struct. 657 (2003) 255;
(n) P. Lemoine, B. Viossat, D. Nguyen-Huy, A. Tomas, G.
Morgant, F.T. Greenaway, J.R.J. Sorenson, J. Inorg. Biochem. 98
(2004) 1734;
References
[1] (a) J.R.J. Sorenson, J. Med. Chem. 19 (1976) 135;
(b) J.R.J. Sorenson, Prog. Med. Chem. 15 (1978) 211.
[2] (a) M.N. Tahir, D. Ulku, E.M. Movsumov, Acta Cryst. C52 (1996)
¨
593;
(o) J. Abdelhak, S. Namouchi Cherni, T. Jouini, Z. Kristallogr.
220 (2005) 183.
´
(b) M.N. Tahir, D. Ulku, E.M. Movsumov, Acta Cryst. C52 (1996)
2436;
¨
¨
[3] ASTRO (5.00), SAINT (5.007), SADABS (5.007). Data Collection and
Processing Software for the SMART System (5.054). Siemens
(BRUKER-AXS) Analytical X-ray Instruments Inc., Madison, WI,
1998.
(c) M. Devereux, M. Curran, M. McCann, Rev.M.T. Casey,
Polyhedron 15 (1996) 2029;
(d) X.S. Tan, W.X. Tang, J. Chen, P.J. Zheng, Polyhedron 15 (1996)
2087;
[4] A. Altomare, M.C. Burla, M. Camalli, G.L. Cascarano, G. Giaco-
vazzo, A. Guagliardi, A. Grazia, G. Moliterni, G. Polidori, R.
Spagna, SIR97 – a program for automatic solution of crystal structures
by direct methods, J. Appl. Crystallogr. 32 (1999) 115.
[5] D.J. Watkin, C.K. Prout, J.R. Carruthers, P.W. Betteridge, R.I.
Prout, CRYSTALS Issue 11, Chemical Crystallography Laboratory,
University of Oxford, UK, 2001.
(e) M.N. Tahir, D. Ulku, E.M. Movsumov, T. Ho¨kelek, Acta Cryst.
¨
C53 (1997) 176;
(f) G. Morgant, B. Viossat, J.-C. Daran, M. Roch-Arveiller, J.-P.
Giroud, D. Nguyen-Huy, J.R.J. Sorenson, J. Inorg. Biochem. 70
(1998) 137;
(g) N.J. Brownless, D.A. Edwards, M.F. Mahon, Inorg. Chim. Acta
287 (1999) 89;
[6] D.J. Watkin, C.K. Prout, L.J. Pearce, CAMERON, Chemical
Crystallography Laboratory, University of Oxford, UK, 1996.
[7] (a) G. Smith, A.W. Hartono, U.D. Wermuth, P.C. Healy, J.M.
White, A.D. Rae, Aust. J. Chem. 58 (2005) 47;
(b) G. Smith, U.D. Wermuth, J.M. White, Acta Cryst. C61 (2005)
464.
[8] (a) R. Kato, Chem. Rev. 104 (2004) 5319;
(b) R.P. Shibaeva, E.B. Yagubskii, Chem. Rev. 104 (2004) 5347;
(c) T. Inabe, H. Tajima, Chem. Rev. 104 (2004) 5505.
[9] C.P. Collier, E.W. Wong, M. Belohradsky, F.M. Raymo, J.F.
Stoddart, P.J. Kuekes, R.S. Williams, J.R. Heath, Science 285
(1999) 391.
(h) G. Morgant, D. Nguyen Huy, J.-C. Daran, B. Viossat, X.
Labouze, M. Roch-Arveiller, F.T. Greenaway, W. Cordes, J.R.J.
Sorenson, J. Inorg. Biochem. 81 (2000) 11;
(i) A. Marzotto, D.A. Clemente, T. Gerola, G. Valle, Polyhedron 20
(2001) 1079;
(j) B. Viossat, G. Morgant, J.R.J. Sorenson, M. Roch-Arveiller, J.-
C. Daran, F.T. Greenaway, D. Nguyen Huy, Ann. Pharm. Fr. 60
(2002) 102;
(k) P. Lemoine, B. Viossat, G. Morgant, F.T. Greenaway, A. Tomas,
D. Nguyen Huy, J.R.J. Sorenson, J. Inorg. Biochem. 89 (2002) 18;
(l) B. Viossat, J.-C. Daran, G. Savouret, G. Morgant, F.T. Green-
away, D. Nguyen Huy, V.A. Pham-Tran, J.R.J. Sorenson, J. Inorg.
Biochem. 96 (2003) 375;
[10] O. Kahn, Molecular Magnetism, VCH, New York, 1993.