One-dimensional and two-dimensional coordination polymers constructed from copper(II) nodes and polycarboxylato spacers: Synthesis, crystal structures and magnetic properties

Article abstract of DOI:10.1016/j.poly.2007.10.011

Four new coordination polymers were obtained by employing polycarboxylato spacers and cationic copper(II) complexes as nodes: ^∞₂[Cu₃(trim)₂(NH₃)₆(H₂O)₃] (1); ^∞

Full text of DOI:10.1016/j.poly.2007.10.011

Available online at www.sciencedirect.com
Polyhedron 27 (2008) 574–582
www.elsevier.com/locate/poly
One-dimensional and two-dimensional coordination
polymers constructed from copper(II) nodes
and polycarboxylato spacers: Synthesis, crystal
structures and magnetic properties
a
b
c
c
´
Cristian D. Ene , Floriana Tuna , Oscar Fabelo , Catalina Ruiz-Perez ,
a
d
a,
*
Augustin M. Madalan , Herbert W. Roesky , Marius Andruh
a
Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Str. Dumbrava Rosie 23, 020464 Bucharest, Romania
b
School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
Laboratorio de Rayos X y Materiales Moleculares, Departamento de Fisica Fundamental II, Facultad de Fı´sica, Universidad de La Laguna, Tenerife, Spain
c
d
Institut fu¨r Anorganische Chemie der Universita¨t, Tammannstr. 4, D-37077 Go¨ttingen, Germany
Received 4 September 2007; accepted 9 October 2007
Available online 19 November 2007
Abstract
Four new coordination polymers were obtained by employing polycarboxylato spacers and cationic copper(II) complexes as nodes:
1[Cu3(trim)2(NH3)6(H2O)3] (1); 1[Cu(tmen)(dhtp)] (2), 1[Cu(tmen)(hitp)(H2O)] (3), 1[Cu(tmen)(nitp)] (4). (H3trim = trimesic acid,
2
1
1
1
H2dhtp = 2,5-dihydroxy-terephthalic acid; H2hitp = 5-hydroxy-isophthalic acid, H2nitp = 5-nitro-isophthalic acid; tmen = N,N,N0,N0-
tetramethyl-ethylenediamine). The crystal structures of the four compounds have been solved. Compound 1 consists of 2D coordination
polymers with heart-shaped meshes, while compounds 2–4 contain infinite zigzag chains. The role of the hydrogen bond interactions in
sustaining the supramolecular solid-state architectures in compounds 1 and 3 is discussed. The cryomagnetic investigation of compounds
1, 2, and 4 reveals antiferromagnetic interactions between the copper ions.
ꢀ 2007 Elsevier Ltd. All rights reserved.
Keywords: Copper complexes; Coordination polymers; Polycarboxylato ligands; Crystal structures; Magnetic properties
1. Introduction
oxylato ligands are: (i) the number of the carboxylato
groups attached to the organic ligand; (ii) the spatial orien-
tation of the carboxylato groups; (iii) the various coordina-
tion modes exhibited by each COOꢀ group; (iv) the
presence of the coligands in the coordination sphere of
the metal ions.
Both flexible aliphatic and rigid aromatic carboxylates
are extensively used as linkers. From the last category we
mention here the trimesic acid, H3trim, which was found
to generate both high-nuclearity clusters [3], and 1D, 2D,
and 3D coordination polymers [4]. Most of these polymers
are constructed from copper(II) ions. Let us recall some of
them, which are relevant to this paper. A one-dimensional
coordination polymer, [Cu(Htma)(H2O)3] results from
a neutral solution containing cupric ions and trimesic
Polycarboxylates are extremely popular as ligands in
designing coordination polymers with various dimensional-
ities and network topologies [1]. The increasing interest in
metal–organic frameworks arises not only from their
intrinsic beauty, but also from their potential applications
in gas storage, catalysis or ion exchange processes [2].
The main factors which influence the rich structural variety
of the coordination polymers constructed from polycarb-
*
Corresponding author.
E-mail address: marius.andruh@dnt.ro (M. Andruh).
0277-5387/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.10.011

C.D. Ene et al. / Polyhedron 27 (2008) 574–582
575
Scheme 1.
acid [4]. In the presence of sodium hydroxide, it results a
2.2. Syntheses
bimetallic coordination polymer, [NaCu(trim)(H2O)4] Æ
2H2O, with a double-sheet architecture [5]. The reaction
between copper(II) nitrate and trimesic acid, under hydro-
thermal conditions, affords a spectacular nanoporous
material, [Cu3(trim)2(H2O)3] [6]. The porosity, catalytic
[7], and the magnetic properties [8] of this material were
intensively investigated. The network topology of the coor-
dination polymers constructed from trimesate linkers is
strongly influenced by ancillary ligands attached to the
copper(II) ions. For example, 2D coordination polymers,
[Cu3(tmen)3(trim)2(H2O)2] Æ 6.5H2O and [Cu3(Ph2SNH)6
(trim)2], were obtained by employing N,N,N0,N0-tetrameth-
ylethane-1,2-diamine (tmen) [9] or S,S0-diphenylsulfimide
(Ph2SNH)[10] as coligands.
2.2.1. 1[Cu3(trim)2(NH3)6(H2O)3] (1)
2
An ethanolic solution (15 mL) of trimesic acid (84 mg,
0.4 mmol) and triethylamine (121.4 mg, 1.2 mmol) was
mixed with a solution of Cu(CF3SO3)2 (217 mg, 0.6 mmol)
in 10 mL water and stirred for about 30 min. An aqueous
ammonia solution was added to the resulted mixture under
stirring until the light blue precipitate dissolved. The
resulted blue solution was allowed to slowly evaporate at
room temperature and the reaction vessel was sealed when
the first crystals appeared. Blue single crystals suitable for
X-ray diffraction were collected after 1 week. Selected IR
data (KBr, cmꢀ1): 3330, 3188, 2925, 1615, 1552, 1438,
1362, 1255, 759, 723.
In this paper we report on four coordination polymers
constructed from aromatic polycarboxylato spacers and
assembling copper(II) complex cations. The following acids
were employed: 1,3,5-benzenetricarboxylic acid (trimesic
acid, H3trim), 2,5-dihydroxy-terephthalic acid (H2dhtp);
5-hydroxy-isophthalic acid, (H2hitp), 5-nitro-isophthalic
(H2nitp) – Scheme 1.
2.2.2. 1[Cu(tmen)(dhtp)] (2)
1
A solution of 2,5-dihydroxy-terephthalic acid (118.9 mg,
0.6 mmol) and triethylamine (121.4 mg, 1.2 mmol) in
10 mL methanol was slowly added to a methanol solution
(10 mL) of [Cu(acac)(tmen)](BF4) (219.4 mg, 0.6 mmol).
The resulted mixture was filtered and the slow evaporation
of the filtrate gave after several days a microcrystalline blue
complex. Single crystals suitable for X-ray diffraction were
obtained by recrystallisation from methanol. The crystals
were collected by filtration and washed with small amounts
of water and methanol. Selected IR data (KBr, cmꢀ1):
2985, 2922, 1587, 1479, 1439, 1420, 1383, 1359, 1240,
1020, 870, 815, 792.
2. Experimental
2.1. Materials
All the chemicals were purchased from commercial
sources and used without any further purification. The
[Cu(acac)(tmen)](ClO4) complex has been previously
reported [10]. The tetrafluoroborate derivative, [Cu(acac)
(tmen)](BF4), was prepared by an alternative method, as
follows: two solutions, one containing acetylacetone
(200.2 mg, 2 mmol) and triethylamine (202 mg, 2 mmol) in
10 mL ethanol, and the other one containing N,N,N0,N0-tet-
ramethyl-ethylenediamine (232.4 mg, 2 mmol) in 10 mL
ethanol, were added rapidly into 20 mL ethanolic solution
of Cu(BF4)2 Æ xH2O (474.3 mg, 2 mmol). The slow evapora-
tion of the resulted mixture gives dark blue crystals.
2.2.3. 1[Cu(tmen)(hitp)(H2O)] (3)
1
A water/methanol (1:1, v/v) solution (10 mL) of 5-
hydroxy-isophthalic acid (36.4 mg, 0.2 mmol) and triethyl-
amine (40.4 mg, 0.4 mmol) was slowly added to a methanol
solution (10 mL) of [Cu(acac)(tmen)](BF4) (73.1 mg,
0.2 mmol). After 2 weeks, a microcrystalline blue com-
pound separated from the resulted mixture on evaporation
at room temperature. Blue single crystals of X-ray diffrac-
tion quality were obtained by recrystallisation from

576
C.D. Ene et al. / Polyhedron 27 (2008) 574–582
methanol. Selected IR data (KBr, cmꢀ1): 3071, 2981, 1578,
1471, 1411, 1349, 1298, 1277, 1216, 1022, 919, 783, 714.
chromated Mo Ka radiation (k = 0.71073 A). Crystal data
˚
and details of the refinement for compounds 1–4 are listed
in Table 1. All calculations for data reduction, structure
solution, and refinement were done by standard procedures
(WINGX) [12].
2.2.4. 1[Cu(tmen)(nitp)] (4)
1
An aqueous solution (10 mL) of 5-nitro-isophthalic acid
(63.3 mg, 0.3 mmol) and triethylamine (60.7 mg, 0.6 mmol)
was mixed with a solution of N,N,N0,N0-tetramethyl-ethy-
lenediamine (34.8 mg, 0.3 mmol) in 5 mL water. The
resulted mixture was slowly added to a solution of
Cu(CF3SO3)2 (108.5 mg, 0.3 mmol) in 10 mL water and
allowed to evaporate at room temperature. Small blue crys-
tals suitable for X-ray diffraction were separated after sev-
eral days. Selected IR data (KBr, cmꢀ1): 2894, 1617, 1586,
1565, 1532, 1460, 1346, 1288, 1020, 808, 733.
The structures of 1–4 were solved by direct methods
using the SHELXS97b computational program. All non-
hydrogen atoms were refined anisotropically by full-matrix
least-squares technique on F2 through the SHELXL97 pro-
gram [13]. The hydrogen atoms for all compounds were
located from difference Fourier maps and refined with
isotropic temperature factors. The final geometrical calcu-
lations and the graphical manipulations were carried
out with PARST97 [14] and DIAMOND [15] programs,
respectively.
2.3. Physical measurements
3. Results and discussion
The IR spectra were recorded as KBr pellets with a Bio-
Rad FTS 135 spectrophotometer in the 4000–400 cmꢀ1
range. Magnetic data were obtained with a Quantum
Design MPMS XL SQUID magnetometer. Magnetic sus-
ceptibility measurements were performed in the 1.8–
300 K temperature range at 1000 G applied magnetic field.
Diamagnetic corrections were applied by using Pascal’s
constants [11]. Isothermal magnetization measurements as
a function of the external magnetic field were performed
up to 7 T at 2 K and 4 K.
3.1. Description of the structures
Four new coordination polymers were obtained:
1[Cu3(trim)2(NH3)6(H2O)3] (1); 1[Cu(tmen)(dhtp)] (2),
2
1
1[Cu(tmen)(hitp)(H2O)] (3), 1[Cu(tmen)(nitp)] (4), and
1
1
their crystal structures were solved. Selected bond lengths
and angles for the four compounds are listed in Table 2.
The first compound was obtained by reacting copper tri-
flate with trimesic acid in the presence of ammonia. Its
structure consists of 2D layers built up by two crystallo-
graphically independent copper(II) ions (Fig. 1). The Cu1
ions, located on a C2-axis, are heptacoordinated by two
ammonia, one aqua and two unsymmetrically chelating car-
boxylato groups from two trim3ꢀ ligands (one of the car-
boxylato oxygens is semicoordinated, Cu1–O4 = 2.825(2)
2.4. X-ray crystallography
X-ray diffraction data on single crystals of 1 and 2–4
were collected on a Huber four circle cradle equipped with
a BRUKER SMART CCD detector and a Nonius Kappa
CCD diffractometer respectively, using graphite-mono-
˚
A). The Cu2 ions show a strongly distorted octahedral
Table 1
Crystallographic data and structure refinement parameters for compounds 1–4
Compound
1
2
3
4
Chemical formula
C
761.10
18H30Cu3N6O15
C14H20CuN2O6
375.86
C14H22CuN2O6
377.87
C14H19CuN3O6
388.86
M (g molꢀ1
)
Temperature (K)
Wavelength (A)
Crystal system
Space group
103(2)
293(2)
293(2)
293(2)
˚
0.71073
monoclinic
C2/c
0.71073
orthorhombic
Pbca
0.71073
orthorhombic
Pbca
0.71073
monoclinic
P21/n
˚
a (A)
13.9591(8)
17.2160(8)
12.5358(7)
90
115.0840(10)
90
2728.5(3)
4
1.853
2.400
1548
1.019
0.0285; 0.0750
0.0301; 0.0762
0.630; ꢀ0.348
16.2826(18)
14.9850(12)
13.4020(17)
90
90
90
3270.0(6)
8
1.527
1.367
1560
14.3045(13)
14.4687(16)
16.3079(9)
90
90
90
3375.2(5)
4
1.487
1.325
1576
12.266(2)
10.5200(12)
13.811(3)
90
111.030(16)
90
1663.4(5)
4
1.545
1.346
800
1.045
0.0676; 0.0917
0.1500; 0.1109
0.469; ꢀ0.413
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
Dcalc (g cmꢀ3
l (mmꢀ1
F (000)
Goodness-of-fit on F2
Final R1, wR2 [I > 2(I)]
R1, wR2 (all data)
)
)
1.046
1.072
0.0519; 0.1030
0.1145; 0.1269
0.562; ꢀ0.491
0.0393; 0.0760
0.0707; 0.0871
0.413; ꢀ0.346
ꢀ3
˚
Largest difference peak and hole (e A
)

C.D. Ene et al. / Polyhedron 27 (2008) 574–582
577
Table 2
˚
Selected bond distances (A) and angles (ꢁ) for compounds 1–4
Compound 1
Cu1–N1
Cu1–O3
Cu1–O4
Cu1–O10
Cu2–N2
Cu2–N3
Cu2–O1
Cu2–O5i
Cu2–O6
Cu2–O11
2.0182(18)
2.0064(15)
2.825(2)
N1–Cu1–O3
N1–Cu1–O3ii
N1–Cu1–O4
N1–Cu1–O4ii
N1–Cu1–O10
N1–Cu1–N1ii
O3–Cu1–O3ii
O3–Cu1–O4
O3–Cu1–O10
O4–Cu1–O4ii
92.37(8)
87.26(8)
82.30(7)
87.99(7)
96.07(6)
167.86(13)
176.47(9)
51.61(5)
91.77(4)
73.97(4)
N2–Cu2–O1
N2–Cu2–O6i
N2–Cu2–O11
N3–Cu2–O1
N3–Cu2–O5i
N3–Cu2–O6i
N3–Cu2–N2
O1–Cu2–O5i
O1–Cu2–O6i
O1–Cu2–O11
O5i–Cu2–O6i
O5i–Cu2–O11
O6i–Cu2–O11
87.51(7)
92.73(7)
82.09(7)
90.71(7)
86.77(7)
89.07(7)
178.19(8)
111.15(6)
165.78(6)
106.38(6)
54.64(6)
142.09(6)
87.72(6)
2.214(3)
1.9821(18)
1.9690(18)
2.0066(15)
2.666(2)
1.9989(15)
2.512(2)
Compound 2
Cu1–N1
Cu1–N2
Cu1–O1
Cu1–O2
Cu1–O5
Cu1–O6
2.023(4)
2.012(4)
2.473(4)
1.993(3)
1.961(3)
2.562(3)
N1–Cu1–N2
N1–Cu1–O2
N2–Cu1–O5
O1–Cu1–O2
O1–Cu1–O6
85.96(16)
162.95(18)
162.55(16)
57.97(13)
O2–Cu1–N2
O2–Cu1–O5
O5–Cu1–N1
O5–Cu1–O6
93.85(14)
91.11(13)
94.12(16)
56.54(16)
138.55(14)
Compound 3
Cu1–N1
Cu1–N2
Cu1–O2
Cu1–O5
Cu1–O16
2.015(2)
2.067(2)
2.2241(17)
1.9719(18)
1.974(2)
N1–Cu1–N2
N1–Cu1–O16
N2–Cu1–O16
O2–Cu1–N1
O2–Cu1–N2
86.58(10)
176.95(10)
90.58(10)
90.99(8)
O2–Cu1–O5
O2–Cu1–O16
O5–Cu1–N1
O5–Cu1–N2
O5–Cu1–O16
109.44(8)
90.50(9)
89.22(8)
152.77(9)
92.79(9)
97.53(8)
Compound 4
Cu1–N2
Cu1–N3
2.022(4)
2.033(4)
2.000(3)
2.464(5)
2.758(4)
1.939(3)
N2–Cu1–N3
N2–Cu1–O1
N2–Cu1–O4vi
N3–Cu1–O1
N3–Cu1–O4vi
86.80(16)
95.20(14)
164.12(14)
158.74(14)
93.80(15)
O1–Cu1–O2
58.25(17)
89.97(14)
95.65(15)
53.10(13)
O1–Cu1–O4vi
O2–Cu1–O3vi
O3vi–Cu1–O4vi
Cu1–O1
Cu1–O2
Cu1–O3vi
Cu1–O4vi
Symmetry code: (i) 0.5 ꢀ x, ꢀ0.5 + y, 1.5 ꢀ z; (ii) ꢀx, y, 2.5 ꢀ z; (iii) x ꢀ 0.5, ꢀy + 0.5, z ꢀ 0.5.
Fig. 1. Coordination environments of the copper ions in crystal 1.
i
i
˚
geometry, being coordinated by one chelating carboxylato
group, one oxygen from a monodentate carboxylato arising
from another trimesate ion, one aqua and two ammonia
ligands. Two out of the trans Cu–O oxygen bonds [Cu2–
O11 = 2.516(2) and Cu2–O5 = 2.666(2) A ( = 0.5 ꢀ x,
ꢀ0.5 + y, 1.5 ꢀ z)] are much longer than the other four
bonds
[Cu2–O1 = 2.0066(15);
Cu2–N2 = 1.9821(18); Cu2–N3 = 1.9690(18) A].
Cu2–O6i = 1.9989(15);
˚

578
C.D. Ene et al. / Polyhedron 27 (2008) 574–582
vi
vi
˚
˚
The construction of the coordination polymer in 1 can
(Cu2)N2ꢁ ꢁ ꢁO3 (Cu1) = 3.044 A ( = 0.5 + x, ꢀ0.5 + y, z);
vii
be described as follows: the trim3ꢀ ligands connect with
two of the carboxylato groups the Cu2 ions, resulting in
zigzag chains. These chains are further interconnected by
the Cu1 ions, which are coordinated to the third carboxy-
lato group arising from trimesate ions belonging to two dif-
ferent chains. The coordination fashion of the trimesate ion
is chelating bis-bidentate and unidentate. Two-dimensional
layers with heart-shaped mashes, which are parallel to the
bc crystallographic plane, are thus formed. The distance
between the copper ions within a mesh are: Cu1ꢁ ꢁ ꢁCu2 =
(Cu2)N3ꢁ ꢁ ꢁO2 (Cu2) = 2.936 A (vii = ꢀx, y, 1.5 ꢀ z); O2
and O3 arise from carboxylato groups.
During the preparation of this manuscript, Long et al.
published the synthesis and crystal structure of another cop-
per complex that contains the same ligands: aqua, ammonia
and trimesate. This compound, obtained via hydrothermal
synthesis, has a different composition, [Cu3(trim)2(NH3)4
(H2O)3] Æ 3H2O, and a different crystal structure, namely a
threefold parallel interpenetration of 2D layers [22].
Compound 2 was obtained by reacting [Cu(tmen)
(acac)](BF4) with 2,5-dihydroxy-terephthalic acid (acac =
acetylacetonato). The investigation of its crystal structure
reveals the formation of infinite zigzag chains constructed
from {Cu(tmen)} nodes and dhtp2ꢀ spacers (Fig. 4). The
copper ions are hexacoordinated with a distorted octahe-
dral geometry: two nitrogen atoms from the tmen ligand
[Cu1–N1 = 2.023(4); Cu1–N2 = 2.012(4) A], and four oxy-
gens from two chelating carboxylato groups arising from
two spacer molecules [Cu1–O1 = 2.473(4); Cu1–O2 =
1.993(3); Cu1–O5 = 1.961(3); Cu1–O6 = 2.562(3) A]. The
hydroxo groups are not involved in the coordination, but
form strong intramolecular hydrogen bonds with one oxy-
0
0
˚
10.159;
Cu2ꢁ ꢁ ꢁCu20 = 8.726;
Cu1 ꢁ ꢁ ꢁCu2 = 9.285 A
(Fig. 2a). Intralayer hydrogen bonds are established
between the aqua ligand coordinated to Cu2 and an oxygen
atom from the unidentate carboxylato group (O11–
H11ꢁ ꢁ ꢁO2 = 1.937 A – Fig. 3a). It is interesting to recall
˚
that within the 3M2+: 2trim3ꢀ stoichiometry, the following
network topologies have been observed so far (M2+ = var-
ious transition metal ions): (1) honeycomb layers with the
trimesate ion located on a threefold axis with all the metal
centres crystallographically equivalent [16–18]; (2) herring-
bone (parquet flooring) [16]; (3) brick wall network [16]; (4)
layers with heart-shaped mashes [19]; (5) double stranded
chain [19]; (6) single zigzag chains with both connecting
and terminal metal ions [3b,20]; (7) T-shaped bilayer [21].
The view along the b crystallographic axis reveals a
stair-like conformation of the layers (Fig. 2b). The layers
stack in the crystal as follows: ABABꢁ ꢁ ꢁ The adjacent A
and B layers (Fig. 3a) interact through hydrogen bonds
established between the aqua ligands coordinated to the
Cu1 and Cu2 ions from one layer and the carboxylato oxy-
gen atoms that are semicoordinated to Cu2 and Cu1 from
˚
˚
˚
gen from each carboxylato groups (O1ꢁ ꢁ ꢁO3 = 2.579 A,
0
˚
O4ꢁ ꢁ ꢁO6 = 2.581 A). Each CuN2O2O2 chromophore is chi-
ral, being related through an inversion centre to the neigh-
bouring copper chromophore, so the chains are not chiral.
The third compound, 1[Cu(tmen)(hitp)(H2O)] (3), con-
1
sists also of infinite zigzag chains with {Cu(tmen)} nodes
connected
through
5-hydroxy-isophthalato
linkers
(Fig. 5). The copper ions are pentacoordinated with a
strongly distorted square-pyramidal geometry. The basal
plane is formed by two nitrogen atoms from the tmen mol-
ecule [Cu1–N1 = 2.015(2); Cu1–N2 = 2.067(2) A], one
aqua ligand [Cu1–O16 = 1.974(2) A], and one carboxylato
oxygen [Cu1–O5 = 1.9719(18) A]; the apical position is
occupied by one carboxylato oxygen from another spacer
[Cu1–O2 = 2.2241(17) A]. A measure of trigonal distortion
iii
iii
˚
˚
the other layer: (Cu1)O10ꢁ ꢁ ꢁO5 (Cu2) = 2.669 A ( = ꢀx,
iv
iv
˚
2 ꢀ y, 2 ꢀ z); (Cu2)O11ꢁ ꢁ ꢁO4 (Cu1) = 2.792 A ( = ꢀx,
1 ꢀ y, 2 ꢀ z). Hydrogen bonds are also established between
the first and the third layer (Fig. 3b), and involve the
˚
˚
v
v
˚
ammonia ligands: (Cu1)N1ꢁ ꢁ ꢁO11 (Cu2) = 3.039 A ( =
˚
ꢀ0.5 + x, 0.5 + y, z), with O11 from the aqua ligand;
Fig. 2. (a) View along crystallographic a-axis of the 2D coordination polymer in 1; (b) view of the layers along the b-axis.

C.D. Ene et al. / Polyhedron 27 (2008) 574–582
579
Fig. 3. (a) Packing diagram showing the hydrogen bond interactions established between the A and B layers for the sake of clarity, the semicoordinate
Cu1–O4 and Cu1–O4ii have been omitted (b) packing diagram showing the hydrogen bond interactions established between the A layers (see text) dotted.
Fig. 4. Perspective view of a zigzag chain in crystal 2, along with the atom numbering scheme.
Fig. 5. Perspective view of a zigzag chain in crystal 3, along with the atom numbering scheme.
for a square-pyramidal geometry can be described using
the parameter s, defined as [(h ꢀ u)/60] · 100, where h
and u are the angles between the donor atoms and the
Cu(II) ion forming the diagonals of the basal plane in a
square-pyramidal geometry [23]. The value of s for the
coordination polyhedron of the Cu(II) ion is s = 40.3.
Strong intrachain hydrogen bond interactions are estab-
lished between the aqua ligand and the uncoordinated oxy-
gens from two carboxylato groups: O16ꢁ ꢁ ꢁO3 = 2.632(2);
The chains are interconnected through hydrogen bonds
involving the OH group, from one chain, and one carboxy-
v
˚
lato oxygen from another one [O1ꢁ ꢁ ꢁO3 = 2.652 A;
(v = ꢀ0.5 + x, y, 0.5 ꢀ y)], resulting in layers paralleling
the crystallographic ac plane (Fig. 6). The shortest intra-
˚
chain Cuꢁ ꢁ ꢁCu distance is 9.919(2) A.
The relative position of the OH group with respect to
the carboxylate influences the coordination and the hydro-
gen bond abilities of such ligands: the ortho OH group
favours the chelating behaviour of the hydroxy-carboxylic
i
i
˚
O16ꢁ ꢁ ꢁO4 = 2.573(2) A ( = 0.5 ꢀ x, ꢀy, 0.5 + z).

580
C.D. Ene et al. / Polyhedron 27 (2008) 574–582
one tmen molecule and two chelating carboxylato groups,
with a strongly distorted octahedral geometry. The equato-
rial plane is described by the nitrogen atoms [Cu1–
˚
N2 = 2.022(4); Cu1–N3 = 2.033(4) A], and by two car-
boxylato oxygen atoms arising from two spacers [Cu1–
vi
˚
O1 = 2.000(3); Cu1-O4 = 1.939(3) A with (vi) = x ꢀ 0.5,
ꢀy + 0.5, z ꢀ 0.5]; the apical positions are occupied by
the other carboxylato oxygens [Cu1–O2 = 2.464(5); Cu1–
vi
˚
O3 = 2.758(4) A]. The distance between the neighbouring
copper ions within a chain is 9.562(5) A. Unlike compound
˚
3, the chains are not connected through hydrogen bonds,
since the hydroxo group in the isophthalic acid is replaced
by the nitro one.
3.2. Magnetic properties
Compounds 1, 2, and 4 have been magnetically charac-
terized by following the temperature dependence of the
magnetic susceptibility as well as the field dependence of
the magnetization at 2 and 4 K. Let us start with com-
pound 1. The vMT versus T curve is shown in Fig. 8 (vM
is the magnetic susceptibility per Cu3 unit). At room tem-
perature, the value of the vMT product (1.20 cm3 molꢀ1 K)
corresponds to the one expected for three uncoupled cop-
per ions. By decreasing the temperature, vMT remains con-
stant down to 200 K, when it starts to decrease slowly, then
more and more, reaching 0.46 cm3 molꢀ1 K at 2 K. This
behaviour indicates an antiferromagnetic interaction
between the copper ions within the 2D layers. Antiferro-
magnetic interactions between the layers, mediated by the
hydrogen bonds, may also occur.
The vMT versus T curves for compounds 2 and 4 (Figs. 9
and 10) suggest that the intrachain exchange interactions
between the copper ions are very weak (we assume that
the absence of the interchain hydrogen bonds prevents
the intermolecular exchange interactions). For such chains
of equally spaced copper(II) ions, the temperature depen-
dence of the magnetic susceptibility is described by the
Bonner and Fisher’s equation [24]:
Fig. 6. Packing diagram for crystal 3 showing the hydrogen bonds
connecting the chains.
acid or the formation of intramolecular hydrogen bonds
(as in the case of compound 2). The meta OH is too far
away to coordinate together with the carboxylato group
to the same metal ion, but it can be involved in intermolec-
ular hydrogen bonds, as observed with compound 3. The
geometrical parameters associated to the hydrogen bonds
in crystals 1–3 are listed in Table 3.
Compound 4, 1[Cu(tmen)(nitp)], has been constructed
1
by employing the 5-nitro-isophthalate as a spacer. Its struc-
ture consists of the zigzag chains similar to those found in
crystal 3 (Fig. 7). The copper ions are hexacoordinated by
Table 3
Geometrical parameters of strong hydrogen bonds in complexes 1–3
˚
˚
D–Hꢁ ꢁ ꢁA
Compound 1
Hꢁ ꢁ ꢁA(A)
Dꢁ ꢁ ꢁA(A)
D–Hꢁ ꢁ ꢁA(ꢁ)
Ng2b2 A
vM
¼
kT
B
O11–H11Aꢁ ꢁ ꢁO2
O10–H10ꢁ ꢁ ꢁO5iii
O11–H11Bꢁ ꢁ ꢁO4iv
N1–H1Cꢁ ꢁ ꢁO11v
N2–H2Bꢁ ꢁ ꢁO3vi
N3–H3Aꢁ ꢁ ꢁO2vii
1.937
1.859
1.998
2.241
2.171
2.085
2.733
2.669
2.792
3.039
3.044
2.936
164.1
170.0
166.9
167.8
160.7
155.2
A ¼ 0:25 þ 0:074975x þ 0:075235x2
B ¼ 1:0 þ 0:9931x þ 0:172135x2 þ 0:757825x3
with x ¼ jJj=kT
Compound 2
O3–H3ꢁ ꢁ ꢁO1
O4-H4ꢁ ꢁ ꢁO6
The best fit to the data, by including the temperature
independent paramagnetism (TIP), leads to the following
1.836
1.878
2.579
2.581
157.9
149.3
values: J = ꢀ0.12 cmꢀ1
,
g = 2.05, TIP = 2.0 · 10ꢀ5
cm3 molꢀ1 (compound 2); J = ꢀ0.53 cmꢀ1
, g = 2.15,
Compound 3
TIP = 4.1 · 10ꢀ5 cm3 molꢀ1 (compound 4). For compounds
2 and 4 the magnetization saturates by increasing the mag-
O16–H161ꢁ ꢁ ꢁO3
O16–H162ꢁ ꢁ ꢁO4i
O1–H11ꢁ ꢁ ꢁO3v
1.824
1.856
2.022
2.632
2.573
2.652
170.1
163.2
168.7
netic field, and reaches the expected value (ꢂ1 Nb molꢀ1
)
Symmetry codes for complex 1: (iii) ꢀx, 2 ꢀ y, 2 ꢀ z; (iv) ꢀx, 1 ꢀ y, 2 ꢀ z;
(v) ꢀ0.5 + x, 0.5 + y, z; (vi) 0.5 + x, ꢀ0.5 + y, z; (vii) ꢀx, y, 1.5 ꢀ z.
Symmetry codes for complex 3: (i) 0.5 ꢀ x, ꢀy, 0.5 + z; (v) ꢀ0.5 + x, y,
0.5 ꢀ y.
at 2 K (see insets to Figs. 9 and 10). In the case of com-
pound 1, the magnetization does not reach saturation even
at 2 K (inset to Fig. 8), indicating stronger Cu(II)–Cu(II)

C.D. Ene et al. / Polyhedron 27 (2008) 574–582
581
Fig. 7. Perspective view of a chain in crystal 4, along with the atom numbering scheme.
Fig. 8. vMT vs. T curve for compound 1 Inset: the field dependence of the
magnetization at T = 2 K (circles) and 4 K (squares).
Fig. 10. vMT vs. T curve for compound 4 (the solid line represents the best
fit curve). Inset: the field dependence of the magnetization T = 2 K
(circles) and 4 K (squares).
4. Conclusions
In conclusion, we have illustrated with new examples the
richness of the chemistry generated by polycarboxylato
ligands acting as bridges. The ancillary ligands attached
to the copper ions influence the topology of the metallic
centers as well. The case of the trimesato complexes is quite
interesting: as mentioned in the Introduction and illus-
trated by compound 1, coordination polymers with various
dimensionalities and solid-state architectures can be
obtained by changing the ancillary ligands.
The values of the exchange parameters were found to be
very low, as expected for polycarboxylato bridges, which
impose long distance between the paramagnetic centres
[3c,9,25,26].
Fig. 9. vM T vs. T curve for compound 2 (the solid line represents the best
fit curve). Inset: the field dependence of the magnetization T = 2 K
(circles) and 4 K (squares).
5. Supplementary material
CCDC 658431, 658432, 658433 and 658434 contain the
supplementary crystallographic data for compounds 1, 2, 3
and 4. 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,
antiferromagnetic interactions than those found in 2 and 4.
The magnitude of the exchange interactions in 1 can not be
estimated, lacking the appropriate vM(T) equation for its
complicated topology of the spin carriers.

582
C.D. Ene et al. / Polyhedron 27 (2008) 574–582
(c) S. De Rosa, G. Giordano, T. Granato, A. Katovic, A. Siciliano, F.
Tripicchio, J. Agric. Food Chem. 53 (2005) 8306;
(d) K. Schlichte, T. Kratzke, S. Kaskel, Micropor. Mesopor. Mater.
73 (2004) 81.
Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or
e-mail: deposit@ccdc.cam.ac.uk.
Acknowledgement
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Financial support from the Alexander von Humboldt
Foundation is gratefully acknowledged.
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