Two-dimensional divalent metal/pimelate coordination polymers incorporating dipodal organodiimines: Crystal structures, thermal properties, and magnetic studies

Article abstract of DOI:10.1016/j.poly.2007.11.006

Hydrothermal synthesis has afforded a series of 2-D coordination polymers incorporating the flexible α,ω-dicarboxylate pimelate ligand (pim) and either the kinked organodiimine 4,4′-dipyridylamine (dpa) or its conformationally flexible congener 1,3-di-4-pyridylpropane (dpp). [M(pim)(dpa)(H₂O)]_n (M = Co, 1-Co; M = Ni, 1-Ni) both display puckered (4,4) rhomboid grid-like 2-D layers that aggregate into 3-D through O-H?O hydrogen bonding. {[Cu₂(pim)₂(dpa)₂] · 5H₂O}_n (2) possesses 2-D slab motifs constructed from the linkage of [Cu₂(pimelate)₂]_n ribbons and [Cu(pimelate)]_n double chains through dpa tethers, entraining discrete water molecule chains with D(8) classification. Employing the longer dpp tether resulted in [Ni(pim)(dpp)]_n (3), which manifested a doubly interpenetrated 2-D (4,4) grid layer morphology. Analysis of the variable temperature magnetic susceptibility of 1-Ni indicated the presence of zero-field splitting as well as possible weak antiferromagnetic coupling between Ni atoms in adjacent layer subunits. In contrast, 2 manifested apparent intradimer ferromagnetic interactions with underlying interdimer antiferromagnetic coupling.

Full text of DOI:10.1016/j.poly.2007.11.006

Available online at www.sciencedirect.com
Polyhedron 27 (2008) 821–834
www.elsevier.com/locate/poly
Two-dimensional divalent metal/pimelate coordination
polymers incorporating dipodal organodiimines: Crystal
structures, thermal properties, and magnetic studies
Subhashree Mallika Krishnan, Matthew R. Montney, Robert L. LaDuca *
Lyman Briggs College, Department of Chemistry, E-30 Holmes Hall, Michigan State University, East Lansing, MI 48825, USA
Received 10 July 2007; accepted 13 November 2007
Available online 20 December 2007
Abstract
Hydrothermal synthesis has afforded a series of 2-D coordination polymers incorporating the flexible a,x-dicarboxylate pimelate
0
ligand (pim) and either the kinked organodiimine 4,4 -dipyridylamine (dpa) or its conformationally flexible congener 1,3-di-4-pyridylpro-
pane (dpp).
[
M(pim)(dpa)(H
2 n
O)] (M = Co, 1-Co; M = Ni, 1-Ni) both display puckered (4,4) rhomboid grid-like 2-D layers that aggregate into 3-
D through O–Hꢀ ꢀ ꢀO hydrogen bonding. {[Cu (pim) (dpa) ] ꢀ 5H O} (2) possesses 2-D slab motifs constructed from the linkage of
2
2
2
2
n
[
Cu
2
(pimelate)
2
]
n
ribbons and [Cu(pimelate)]
n
double chains through dpa tethers, entraining discrete water molecule chains with D(8)
(3), which manifested a doubly interpenetrated 2-D (4,4) grid
classification. Employing the longer dpp tether resulted in [Ni(pim)(dpp)]
n
layer morphology. Analysis of the variable temperature magnetic susceptibility of 1-Ni indicated the presence of zero-field splitting as
well as possible weak antiferromagnetic coupling between Ni atoms in adjacent layer subunits. In contrast, 2 manifested apparent intra-
dimer ferromagnetic interactions with underlying interdimer antiferromagnetic coupling.
Ó 2007 Elsevier Ltd. All rights reserved.
Keywords: Coordination polymer; Copper; Cobalt; Nickel; Pimelate; Dipyridylamine; Dipyridylpropane; Crystal structure; Antiferromagnetism; Ferro-
magnetism
1
. Introduction
curtailing smaller anions. A wide range of structural pat-
terns occurs in these systems, based on the disposition of
the donor groups within the dicarboxylate moieties, coor-
dination geometry preferences, and an array of available
binding carboxylate modes. While the predominant focus
has rested on aromatic dicarboxylates, aliphatic a,x-dicar-
boxylate ligands have also shown their utility in the con-
struction of novel coordination polymers due to their
ability to undergo facile conformational interconversions
[6].
Over the past decade many researchers have undertaken
significant effort towards the synthesis and characterization
of metal dicarboxylate and tricarboxylate coordination
polymers because of the capability of these materials in
diverse applications such as gas storage [1], small molecule
shape-selectivity [2], ion-exchange [3], catalysis [4], and
optical devices [5]. In these phases dianionic dicarboxylate
ligands not only serve to link metal cations into higher
dimensionalities but also provide necessary charge balance,
thereby permitting formation of a large number of neutral
coordination polymer frameworks that exclude porosity-
More recently, elaboration of dicarboxylate-containing
inorganic/organic hybrid materials has been achieved
through the incorporation of neutral organodiimine tether-
0
0
ing ligands such as the rigid-rod 4,4 -bipyridine (4,4 -bpy),
which can connect metal cations through its distal pyridyl
nitrogen donor atoms into a host of structurally interesting
*
Corresponding author. Tel.: +1 5174322268.
E-mail address: laduca@msu.edu (R.L. LaDuca).
0
277-5387/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.11.006

822
S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
solids with intriguing physicochemical properties [7–10].
For example, the 2-D layered phase {[Zn(isophthal-
netic properties of these new coordination polymers are
also reported herein.
0
ate)(4,4 -bpy)(H O)] ꢀ 1.5H O} manifested intense blue
2
2
0
luminescence [8], [Co(thiophene-2,5-dicarboxylate)(4,4 -
bipy)] displayed field-dependent spin-flop magnetic behav-
2. Experimental
ior at low temperatures [9], and the interpenetrated 3-D
2.1. General considerations
0
material [Zn(terephthalate)(4,4 -bpy)0.5] exhibited
a
remarkable ability to chromatographically separate linear
and branched alkanes [10]. This work has been extended
to aliphatic a,x-dicarboxylates, with some divalent metal
CoCl ꢀ 6H O, NiCl ꢀ 6H O (Fisher) and pimelic acid
2
2
2
2
(Aldrich) were obtained commercially. The organodiimine
0
4,4 -dipyridylamine (dpa) was prepared via a published
0
adipate coordination polymers incorporating 4,4 -bpy or
procedure [14]. Water was deionized above 3 MX in-house.
Thermogravimetric analysis was performed on a TA
Instruments TGA 2050 Thermogravimetric Analyzer with
a heating rate of 10 °C/min up to 900 °C. Elemental Anal-
ysis was carried out using a Perkin–Elmer 2400 Series II
CHNS/O Analyzer. IR spectra were recorded on powdered
samples on a Perkin–Elmer Spectrum One instrument.
Powder X-ray diffraction patterns were obtained via H–
2H scans performed on a Rigaku Rotaflex instrument. Var-
iable temperature magnetic susceptibility data (2–300 K)
was collected on a Quantum Design MPMS SQUID mag-
netometer at an applied field of 0.1 T. After each tempera-
ture change the sample was kept at the new temperature for
5 min before magnetization measurement to ensure ther-
mal equilibrium. The susceptibility data were corrected
for diamagnetism using Pascal’s constants.
1
,2-di-4-pyridylethane (bpe). In many of these cases doubly
interpenetrated 3-D networks were observed [11].
For some time, we have been interested in the synthesis
and characterization of coordination polymer materials
0
containing the organodiimine 4,4 -dipyridylamine (dpa,
0
see Scheme 1). Unlike 4,4 -bpy, dpa possesses a kinked dis-
position of its terminal nitrogen donor atoms as well as a
hydrogen bonding locus at its central secondary amine sub-
unit that can assist in the formation of novel structural pat-
terns. Neighboring dpa entities can also interact with each
other or with other aromatic subunits through supramolec-
ular p–p stacking interactions. Prior results from our labo-
ratory have shown that coordination polymers with novel
structural motifs can result from the hydrothermal combi-
nation of metal salts with aliphatic dicarboxylates and dpa
[
12,13]. Five different divalent metal coordination polymers
were prepared utilizing succinate and dpa tethering ligands.
2
.2. Preparation of [Ni(pim)(dpa)(H O)] (1-Ni)
2 n
Among these, {[Zn(succinate)(dpa)] ꢀ H O} displayed a
2
rarely seen fourfold interpenetrated SrAl -type lattice,
2
NiCl ꢀ 6 H O (0.088 g, 0.37 mmol), dpa (0.063 g,
2
2
and {[Ni(dpa) (succinate) ]Cl} manifested an unprece-
2
0.5
0
.37 mmol) and H pim (0.059 g, 0.37 mmol) were added
1
0
2
dented 5-connected self-penetrated network with 6 topol-
to 10 mL of distilled H O in a 23 mL Teflon lined Parr acid
digestion bomb. The pH was adjusted to 5.7 with 0.7 mL of
a 1.0 M NaOH solution. The bomb was sealed, heated to
2
ogy [12]. [Ni(adipate)(dpa)(H O)] exhibited the first-ever
2
example of triple interpenetration within the PtS structure
type [13]. In the present study, we have investigated dpa-
containing coordination polymers based on pimelate
1
20 °C for 53 h, and then gradually cooled to ambient tem-
perature. Green plates of 1-Ni (0.109 g, 73% yield based on
Ni) were obtained after filtration, washing with distilled
water and acetone, and drying in air. Crystals of 1-Ni were
stable indefinitely in air. Anal. Calc. for C H NiN O
5
2
ꢁ
(
pim ), an even longer a,x-dicarboxylate tethering ligand
with enhanced conformational flexibility. Significant differ-
ences in their two-dimensional structures were promoted
by changes in metal coordination geometry. As the chemis-
try of dual pimelate/tethering organodiimine coordination
polymers remains largely unexplored, we have also investi-
gated the effect of utilizing the more flexible 1,3-dipyridyl-
propane (dpp) ligand. This change results in
interpenetration absent in the dpa cases. Thermal and mag-
1
7
21
3
1-Ni: C, 50.28; H, 5.21; N, 10.35. Found: C, 50.30; H, 5.27;
ꢁ1
N, 10.41%. IR (cm ): 3250 w br, 2929 w, 1593 s, 1542
m, 1513 s, 1476 m, 1453 w, 1437 m, 1421 m, 1386 s, 1334
s, 1291 w, 1202 m, 1083 w, 1060 m, 1024 m, 904 w, 873
w, 827 s, 764 w, 731 s, 661 m.
2.3. Preparation of [Co(pim)(dpa)(H O)] (1-Co)
2 n
The procedure for the synthesis of 1-Ni was followed
with the use of CoCl ꢀ 6H O (0.088 g, 0.37 mmol) as the
2
2
metal source. Magenta plates of 1-Co (0.031 g, 21% yield
based on Co) were obtained after filtration, washing with
distilled water and acetone, and drying in air. Crystals of
1
-Co were stable indefinitely in air. Anal. Calc. for
C H CoN O 1-Co: C, 50.26; H, 5.21; N, 10.34. Found:
1
7
21
3
5
ꢁ1
C, 50.46; H, 4.82; N, 10.36%. IR (cm ): 3250 w br, 2927
w, 1591 s, 1513 s, 1476 w, 1454 w, 1437 m, 1420 w, 1383
Scheme 1.

S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
823
m, 1336 s, 1310 w, 1292 w, 1233 w, 1082 m, 1058 m, 1020 s,
moieties and all aquo ligands were found via Fourier
difference maps, restrained at fixed positions, and then
refined isotropically with thermal parameters 1.2 times the
9
04 m, 873 w, 827 s, 801 w, 732 s, 717 m, 660 s.
2
.4. Preparation of {[Cu (pim) (dpa) ] ꢀ 5H O} (2)
average U values of the atoms to which they are bound.
2
2
2
2
n
ij
Distended thermal ellipsoids for some of the pimelate
carbon atoms in 2 are indicative of some amount of posi-
tional or thermal disorder; however, this could not be suc-
cessfully modeled. Relevant crystallographic data is listed
in Table 1.
CuCl ꢀ 2H O (0.063 g, 0.37 mmol), H pim (0.059 g,
2
2
2
0
1
.37 mmol) and dpa (0.127 g, 0.74 mmol) were placed into
0 g (555 mmol) distilled H O in a 23 mL Teflon-lined Parr
2
acid digestion bomb (1:2:1500 mol ratio). The mixture was
acidified to pH 4.5 with 0.5 mL of a 1.0 M HCl solution.
The bomb was sealed and heated at 150 °C for 24 h, where-
upon it was cooled slowly in air to 25 °C. Small blue crys-
tals of 2 (0.089 g, 55% yield based on Cu) were isolated
after washing with distilled water. Because the material
effuses its waters of crystallization slowly upon standing,
it was kept for long-term storage in its mother liquor. Anal.
Calc. for C H Cu N O (2): C, 46.62; H, 5.52; N, 9.60.
Found: C, 43.36; H, 4.92; N, 9.03%. Elemental analyses
showed lower than expected values on multiple samples,
ascribed to either incomplete combustion or the presence
of an amorphous inorganic impurity, as the powder
XRD spectrum of freshly prepared 2 coincides exactly with
that predicted from the single-crystal X-ray structure. IR
4. Results and discussion
4.1. Synthesis and spectral characterization
The coordination polymers 1–3 were prepared cleanly
under hydrothermal conditions via combination of the
3
4
48
2
6
13
appropriate metal chloride, H pim, and either dpa (1, 2)
2
or dpp (3). The infrared spectra of 1–3 were consistent with
their formulations. Sharp, medium intensity bands in the
ꢁ1
ꢁ1
range of ꢂ1600 cm
to ꢂ1200 cm
were ascribed to
stretching modes of the pyridyl rings of the dpa moieties
[
18]. Features corresponding to pyridyl ring puckering
ꢁ1
mechanisms were evident in the region between 820 cm
and 600 cm . Asymmetric and symmetric C–O stretching
ꢁ1
(
cm ): 3250 w br, 2927 w, 1593 s, 1526 s, 1445 m, 1394
ꢁ1
s, 1358 s, 1291 m, 1256 w, 1205 s, 1062 m, 1026 s, 907 w,
modes of the carboxylate moieties were evidenced by very
8
16 s, 760 w, 729 w, 664 w.
ꢁ1
strong, slightly broadened bands at ꢂ1590 cm
and
ꢁ
1
ꢁ1
ꢂ1340 cm . Broad bands in the region of ꢂ3400 cm
2
.5. Preparation of [Ni(pim)(dpp)] (3)
n
ꢁ1
to ꢂ3200 cm in all cases represent N–H stretching modes
within the dpa ligands and O–H stretching modes within
water molecules of crystallization. The broadness of these
latter spectral features is caused by significant hydrogen
bonding pathways within 1–3. Phase purity was verified
with powder XRD by comparison with powder patterns
predicted from the single crystal structures.
NiCl ꢀ 6H O (0.088 g, 0.37 mmol), dpp (0.147 g,
2
2
0
.74 mmol) and H pim (0.059 g, 0.37 mmol) were added
2
to 10 mL of distilled H O in a 23 mL Teflon lined Parr acid
2
digestion bomb. The bomb was sealed, heated to 150 °C for
4
4 h, and then gradually cooled to ambient temperature.
Green blocks of 3 (0.050 g, 33% yield based on Ni) were
obtained after filtration, washing with distilled water and
acetone, and drying in air. Crystals of 3 were stable indef-
initely in air. Anal. Calc. for C H NiN O 3: C, 57.87; H,
4.2. Structural description of [M(pim)(dpa)(H
(1-Ni, M = Ni; 1-Co, M = Co)
O)]
n
2
2
0
24
2
4
5
.83; N, 6.75. Found: C, 57.65; H, 5.74; N, 6.87%. IR
ꢁ1
(
cm ): 2921 w, 1614 m, 1560 m, 1537 s, 1510 m, 1432 s,
1-Ni and 1-Co are isomorphous, both crystallizing in the
monoclinic space group P2 /c and possessing an asymmet-
ric unit consisting of a metal atom, one doubly deproto-
1
8
410 s, 1314 m, 1213 w, 1140 w, 1069 w, 1023 m, 920 w,
94 m, 862 m, 817 m, 808 m, 723 m, 660 m.
1
2
ꢁ
nated pim
(pim) moiety, one dpa ligand, and one
3
. X-ray crystallography
bound water molecule. The asymmetric unit of 1-Ni is dis-
played in Fig. 1; that of 1-Co is virtually identical. The
coordination spheres about the divalent metal ions in these
Single crystals of all materials were subjected to single
crystal X-ray diffraction using a Bruker-AXS SMART 1k
CCD instrument. Reflection data was acquired using graph-
ite-monochromated Mo Ka radiation (k = 0.71073 A). The
materials are slightly distorted [MO N ] octahedra, with
4 2
the two nitrogen donors from two different dpa molecules
oriented in a cis fashion with respect to each other. Two
of the oxygen donors (O1, O2) belong to the chelating ter-
˚
data were integrated via SAINT [15]. Lorentz and polariza-
tion effect and empirical absorption corrections were
applied with SADABS [16]. The structures were solved using
2
ꢁ
minus of a pim ligand. The aquo ligand (O5) is disposed
in a cis manner with respect to the remaining oxygen donor
(O3), part of a monodentate carboxylate group of another
2
direct methods and refined on F using SHELXTL [17]. All
2
ꢁ
non-hydrogen atoms were refined anisotropically. Hydro-
gen atoms bound to carbon atoms were placed in calculated
positions and refined isotropically with a riding model. The
hydrogen atoms bound to the central nitrogen of the dpa
(but crystallographically identical) pim
ligand. Bond
lengths and angles (Table 2) about the metal ions are stan-
dard for distorted octahedral coordination complexes with
one chelating ligand. The bond lengths for 1-Ni are slightly

824
S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
Table 1
Crystal and structure refinement parameters for 1–3
1-Ni
1-Co
2
3
Empirical formula
Formula weight
Collection T (K)
Color and habit
Crystal size (mm)
C
406.08
173(2)
green plate
17
H
21NiN
3
O
5
C
406.30
293(2)
17
H
21CoN
3
O
5
C
875.86
173(2)
34
H
48Cu
2
N
6
O
13
C
415.12
173(2)
20 24 2 4
H N NiO
magenta plate
blue block
green block
0.25 ꢃ 0.20 ꢃ 0.02
0.35 ꢃ 0.30 ꢃ 0.05
0.20 ꢃ 0.18 ꢃ 0.12
0.55 ꢃ 0.45 ꢃ 0.40
˚
k (A)
0.71073
0.71073
0.71073
0.71073
Crystal system
Space group
monoclinic
monoclinic
triclinic
monoclinic
P2 /c
1
ꢀ
P2
1
/c
P2
1
/c
P1
˚
a (A)
8.6725(15)
16.176(3)
13.211(2)
90
104.725(3)
90
1792.5(5)
4
1.505
8.736(4)
16.295(7)
13.337(6)
90
104.513(7)
90
1838.0(13)
4
1.468
9.9468(17)
10.3520(18)
19.365(3)
77.728(3)
82.270(3)
84.770(3)
1926.7(8)
2
7.572(4)
17.096(9)
15.499(9)
90
93.288(9)
90
2003.1(19)
4
1.377
˚
b (A)
˚
c (A)
a (°)
b (°)
c (°)
˚
3
V (A )
Z
ꢁ3
D
calc (g cm
)
1.506
1.125
ꢁ
1
l (mm
)
1.116
0.966
0.995
Minimum/maximum, T
hkl ranges
0.758
0.878
0.851
0.899
ꢁ11 6 h 6 11,
ꢁ11 6 h 6 11,
ꢁ21 6 k 6 21,
ꢁ17 6 l 6 17
20264
ꢁ13 6 h 6 13,
ꢁ13 6 k 6 13,
ꢁ25 6 l 6 25
23946
ꢁ9 6 h 6 9,
ꢁ22 6 k 6 22,
ꢁ20 6 l 6 20
21772
ꢁ
21 6 k 6 21,
17 6 l 6 17
ꢁ
Total reflections
21812
Unique reflections
4 410
4274
9214
4581
R
int
0.1542
244/4
0.0351
247/4
0.0508
0.0360
0.0804
0.0745
0.388/ꢁ0.256
0.0772
525/15
0.1375
0.0730
0.1678
0.1439
0.929/ꢁ0.578
0.0244
244/0
0.0329
0.0276
0.0705
0.0678
0.279/ꢁ0.180
Parameters/restraints
R
R
a
1
(all data)
0.1363
0.0713
0.1592
0.1361
0.588/ꢁ0.756
1
(I > 2r(I))
b
wR
wR
2
(all data)
(I > 2r(I))
2
Maximum/minimum
residual (e /A )
Goodness-of-fit
ꢁ
˚
3
1.042
1.036
1.028
1.052
P
P
a
R
wR
1
=
kF
o
jꢁjF
c
k/ jF
o
2 2
j.
P
P
b
2
2 2 1/2
] }
2
= { [w(F
o
ꢁ F
c
) ]/ [wF
o
.
Fig. 1. The asymmetric unit of 1-Ni with thermal ellipsoids drawn at 50% probability and partial atom numbering scheme.

S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
825
Table 2
Selected bond distance (A) and angle (°) data for 1-M
carboxylate termini vary by ꢂ0.40 A, reflective of
enhanced p-type character in the between the carboxylate
C atom and the unligated oxygen atoms. The [M(pim)]n
chains in turn are connected through tethering dpa
ligands to generate a ruffled [M(pim)(dpa)(H O)] two-
˚
˚
1
-Ni
#
1
#1
#2
Ni1–N3
Ni1–O3
Ni1–O5
Ni1–N1
Ni1–O2
Ni1–O1
O1–C11
O2–C11
O3–C17
O4–C17
2.053(4)
2.068(3)
2.070(3)
2.103(4)
2.121(3)
2.143(3)
1.267(5)
1.264(6)
1.274(6)
1.236(6)
N3 –Ni1–O3
89.21(14)
90.98(14)
92.05(13)
95.93(15)
172.70(14)
93.04(14)
98.10(14)
85.52(12)
170.55(13)
88.62(14)
159.49(14)
86.04(12)
109.09(13)
87.35(14)
61.67(12)
#
2
#1
N3 –Ni1–O5
#2
2
n
O3 –Ni1–O5
#1
dimensional (4,4) layer motif parallel to the ab crystal
plane (Fig. 3). Each metal ion is covalently connected to
four others, with two connections each via pim
dpa ligands. The metal–metal contact distances through
the pim ligands measure 8.988 A and 9.056 A for 1-Ni
and 1-Co, respectively; the corresponding contact dis-
tances through the dpa tethers are 11.350 A and
1.465 A. In order to accommodate the necessary orienta-
tion for appropriate covalent bonding, the dpa molecule
undergoes a significant inter-ring torsion (47.1° in 1-Ni
and 46.7° in 1-Co). The incipient void spaces within the
resulting puckered rhomboid circuits in 1-Ni measure
N3 –Ni1–N1
#2
O3 –Ni1–N1
O5–Ni1–N1
2
ꢁ
and
#1
N3 –Ni1–O2
#2
O3 –Ni1–O2
O5–Ni1–O2
N1–Ni1–O2
2ꢁ
˚
˚
#1
˚
N3 –Ni1–O1
#2
O3 –Ni1–O1
O5–Ni1–O1
N1–Ni1–O1
O2–Ni1–O1
1
˚
1
-Co
#
3
#3
O4 –Co1–O5
Co1–O4
Co1–O5
2.091(2)
2.092(2)
2.105(2)
2.159(2)
2.161(2)
2.187(2)
1.268(3)
1.255(3)
1.239(3)
1.271(2)
90.44(6)
90.50(6)
90.04(6)
172.88(6)
93.15(7)
95.64(6)
86.19(6)
171.27(6)
98.04(6)
89.38(7)
86.60(6)
111.70(6)
158.07(6)
86.36(6)
60.10(6)
˚
#3
8.673 and 16.176 A (via through-space Ni–Ni distances),
with Ni–Ni–Ni angles of 48.8°, 48.8°, 90.9° and 128.3°.
The corresponding through-space Co–Co distances in 1-
O4 –Co1–N1
O5–Co1–N1
Co1–N1
Co1–N3
Co1–O2
Co1–O1
C11–O1
C11–O2
C17–O3
C17–O4
#
4
#3
#4
O4 –Co1–N3
#
4
O5–Co1–N3
˚
Co are slightly longer at 8.736 and 16.295 A with virtually
#4
N1 –Co1–N3
identical Co–Co–Co angles.
#3
O4 –Co1–O2
O5–Co1–O2
N1–Co1–O2
The covalent connectivity within the layer is supple-
mented by supramolecular hydrogen bonding donation
from the amine functional group of dpa to the oxygen
atom O3 within the chelating carboxylate moiety. In
addition, the aquo ligand provides a hydrogen bonding
point of contact to the unligated oxygen atom of type
O4 within the monodentate carboxylate group, possibly
preventing a bis-monodentate bis-monodentate binding
mode for the pim ligand. The puckering of the individ-
ual 2-D layers causes an alternation of the position of
the pim ligands above and below the layer, allowing
interlayer hydrogen bonding between the aqua ligands
and oxygen atoms of type O1 within the chelating car-
boxylate groups. These supramolecular interactions result
in stacking of the [M(pim)(dpa)(H O)] layers along the c
2 n
crystal direction to establish the pseudo 3-D crystal
structures of 1-M (Fig. 4). The interlayer metal–metal
contact distances are 5.113 A and 5.095 A in 1-Ni and
1-Co, respectively, significantly closer than the intralayer
metal–metal distances. Metrical parameters for the classi-
cal hydrogen bonding interactions in 1-M are given in
Table 3.
#4
N3 –Co1–O2
#4
O4 –Co1–O1
O5–Co1–O1
N1–Co1–O1
N3 –Co1–O1
O2–Co1–O1
#2
Symmetry transformations to generate equivalent atoms: #1 ꢁx + 1,
y + 1/2, ꢁz + 3/2; #2 ꢁx + 2, y + 1/2, ꢁz + 3/2; #3 ꢁx + 1, y + 1/2,
2
ꢁ
ꢁz + 1/2; #4 ꢁx, y ꢁ 1/2, ꢁz + 1/2.
2
ꢁ
shorter than those for 1-Co, consistent with well-estab-
lished ionic radius trends [19].
2
ꢁ
The pim ligands adopt a gauche–anti–anti–anti con-
formation (four C-atom torsion angles = 69.19°, 173.08°,
1
78.17° and 170.39° for 1-Ni) and bridge neighboring
˚
˚
metal atoms in an exobidentate chelating/monodentate
fashion to form undulating [M(pim)] chain motifs that
n
course parallel to the b crystal axis (Fig. 2). While the
chelating carboxylates in 1-M display symmetric binding
to the metal, the C–O bond lengths of the monodentate
Fig. 2. [Ni(pim)]
n
chain motif in 1-Ni.

826
S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
2 n
Fig. 3. Face-on view of the [Ni(pim)(dpa)(H O)] 2-D layers in 1-Ni. Intralayer hydrogen bonding is shown as dashed lines.
2 n
Fig. 4. Stacking of [M(pim)(dpa)(H O)] layers along the c crystal direction by supramolecular interlayer hydrogen bonding (shown as dashed lines).
4
(
.3. Structural description of {[Cu (pim) (dpa) ] ꢀ 5H O}
pyramidal coordination geometry (s = 0.01) [20], with
one nitrogen donor from a dpa-A ligand, one nitrogen
donor from a dpa-B ligand, and oxygen donors from two
different pim-B ligands situated within the basal plane.
The nitrogen donors are oriented in a trans-fashion within
the basal plane, as are the oxygen donors. The coordina-
tion sphere about Cu1 is completed by an oxygen donor
from a third pim-B ligand lying in the axial position. The
bond lengths and angles about Cu1 (Table 4) are consistent
2
2
2
2
n
2)
The asymmetric unit of 2 (Fig. 5) was found to contain
two crystallographically distinct divalent copper atoms,
2
ꢁ
two fully deprotonated pim dianions (C21–C27/O1–O4,
pim-A; C31–C37/O5–O8, pim-B), two dpa ligands (C1–
C10/N1–N3, dpa-A; C11–C20/N4–N6, dpa-B), and five
water molecules of crystallization, one of which (O5W) is
disordered equally over two positions. One of the copper
atoms (Cu1) adopts a virtually perfect {CuN O } square
2
+
with the well-known Jahn-Teller distortion for Cu . The
other crystallographically distinct Cu atom (Cu2) exhibits
2
3

S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
827
Table 3
Hydrogen bonding distance (A) and angle (°) data for 1–2
˚
.
. .
. . .
d(H A)
. . .
d(D A)
D–H
-Ni
O5–H5A O1
A
\DHA
Symmetry transformation for A
1
.
. .
. .
1.87(2)
1.90(3)
1.93(2)
177(5)
142(5)
166(5)
2.707(4)
2.618(5)
2.799(5)
ꢁx + 2, y + 1/2, ꢁz + 3/2
ꢁx + 2, ꢁy, ꢁz + 1
.
O5–H5B O4
N2–H2N O3
.
. .
1
-Co
.
. .
O5–H5A O1
O5–H5B O3
N2–H2N O4
1.88(2)
1.79(2)
1.98(2)
169(2)
169(3)
173(2)
2.711(2)
2.623(3)
2.828(2)
ꢁx + 1, ꢁy, ꢁz
.
. .
ꢁx, y + 3/2, ꢁz + 1/2
ꢁx, y + 1/2, ꢁz + 1/2
.
. .
2
.
. .
N2–H2N O1W
N5–H5N O6
O1W–H1WA O4
O1W–H1WB O6
O2W–H2WA O3W
O2W–H2WB O1W
O3W–H3WA O3
O3W–H3WB O2
2.00(2)
2.02(3)
1.96(3)
1.88(3)
2.06(2)
2.08(2)
2.00(3)
2.16(4)
2.17(4)
2.07(3)
1.95(6)
178(5)
157(5)
157(6)
164(5)
143(4)
147(4)
163(7)
151(7)
150(7)
163(7)
128(7)
2.877(6)
2.845(6)
2.768(6)
2.690(5)
2.846(7)
2.926(7)
2.825(6)
2.921(6)
2.940(6)
2.905(2)
2.564(2)
x ꢁ 1, y, z
.
. .
ꢁx + 1, ꢁy + 2, ꢁz
ꢁx + 1, ꢁy + 2, ꢁz
.
. .
.
. .
.
. .
x ꢁ 1, y ꢁ 1, z
.
. .
ꢁx + 1, ꢁy + 1, ꢁz
.
. .
.
. .
x, y + 1, z
.
. .
O4W–H4WA O7
O4W–H4WB O5WA
O4W–H4WB O5WB
.
. .
x ꢁ 1, y, z
x ꢁ 1, y, z
.
. .
Fig. 5. Asymmetric unit of 2 with thermal ellipsoids shown at 50% probability and partial atom numbering scheme. Most hydrogen atoms have been
omitted for clarity.
a {trans-CuN O } square planar coordination environ-
atom lies in the basal plane of one Cu1 square pyramid,
and is in the axial position of another, resulting in an asym-
metric rhomboid four-membered ring. The through-space
2
2
ment, with the nitrogen donors belonging to two crystallo-
graphically distinct dpa ligands and the oxygen donors
provided by two different pim-A ligands. The O1–Cu2–
O3 bond angle (Table 3) is ꢂ20° narrower than the corre-
sponding trans N1–Cu2–N4 bond angle, a deviation from
idealized square planar geometry likely provoked by long
range Cuꢀ ꢀ ꢀO interactions and other supramolecular effects
˚
˚
Cu1–Cu1 and O8–O8 distances are 3.391 A and 2.796 A,
respectively; the Cu–O–Cu and O–Cu–O angles within
the rhomboid {Cu O } unit subtend 101.2(5)° and
2
2
78.8(5)°. Adjacent {Cu O } units are linked to two others
2
2
along the b crystal direction by means of tethering pim-B
dianions in an anti–gauche–anti–anti conformation (C–C–
C–C torsion angles: 177.0°, 25.7°, 175.6°, 174.6°), thereby
forming 1-D [Cu (pim) ] ribbon motifs (Fig. 6A). The
(
vide infra).
Extension of the structure about Cu1 reveals {Cu O }
2
2
bimetallic kernels formed by the junction of two adjacent
2
2 n
Cu1 atoms by two l -bridging oxygen atoms of type O8
belonging to two different pim-B units. Each O8 oxygen
Cu–Cu distance through the kinked pim-B ligand is
2
2
ꢁ
˚
8.888 A. The pim moieties in this chain are exotridentate,

828
S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
Table 4
Selected bond distance (A) and angle (°) data for 2
interactions (2.700 A, drawn as dashed lines in Fig. 6B).
˚
˚
If these interactions are considered ‘‘bonds”, {Cu O }
2
2
Cu1–O5
Cu1–O8
Cu1–N6
Cu1–N3
1.950(3)
1.991(3)
2.006(4)
2.006(4)
2.388(3)
1.974(4)
1.987(4)
1.989(3)
1.996(4)
O5–Cu1–N3
88.05(15)
92.17(15)
175.65(16)
104.69(12)
78.88(12)
91.30(14)
91.69(14)
91.67(15)
154.42(16)
91.86(15)
87.87(16)
174.69(17)
90.83(15)
101.12(12)
bimetallic units similar to those within the Cu1-based rib-
bons can be invoked. However, the Cu2–Cu2 distances
#
1
#1
O8 –Cu1–N3
#
2
#2
N6 –Cu1–N3
˚
˚
#
3
within these units are ꢂ0.25 A longer, at 3.647 A, with a
O5–Cu1–O8
#
3
4
#1
#3
#3
Cu2–O1ꢀ ꢀ ꢀCu2 angle of 100.99°. It is likely that the confor-
Cu1–O8
Cu2–O3
O8 –Cu1–O8
2
ꢁ
#
#2
N6 –Cu1–O8
mational flexibility of the pim tethers assists in the for-
mation of two different 1-D copper dicarboxylate motifs
in 1.
#
3
Cu2–N4
Cu2–O1
Cu2–N1
N3–Cu1–O8
#4
O3 –Cu2–N4
O3 –Cu2–O1
N4–Cu2–O1
#4
Alternating [Cu (pim) ] ribbons (based on Cu1) and
2
2 n
#
1
#4
[Cu(pim)] double chain subunits (based on Cu2) are sub-
O5–Cu1–O8
O5–Cu1–N6
176.41(13)
88.13(15)
91.51(14)
O3 –Cu2–N1
n
#
2
N4–Cu2–N1
O1–Cu2–N1
sequently bridged together by tethering dpa ligands to
establish a 2-D [Cu (pim) (dpa) ] neutral coordination
#
1
#2
O8 –Cu1–N6
2
2
2
#1
#4
Cu1 –O8–Cu1
ꢀ
polymer slab that lies parallel to the ð101Þ crystal plane
Symmetry transformations to generate equivalent atoms: #1 ꢁx + 1, ꢁy,
z + 1; #2 x + 1, y ꢁ 1, z + 1; #3 x, y + 1, z; #4 x, y ꢁ 1, z.
(
Fig. 7). The Cu1–Cu2 distances measure 11.485 A
˚
ꢁ
(
through dpa-A with an inter-ring torsion angle of 28.7°)
˚
and 11.527 A (through dpa-B with an inter-ring torsion
angle of 29.6°). The covalent connectivity within the slab
motif is augmented by p–p stacking between dpa-A and
dpa-B ligands (centroid-to-centroid distances 3.647(1) A
and 3.631(1) A), imposed by the presence of the {Cu O }
binding to Cu in a monodentate fashion at O5, and bridg-
ing two Cu atoms via their O8 termini. An interaction
between Cu1 and the unligated carboxylate oxygen atom
˚
˚
˚
O7 is evident, with a Cuꢀ ꢀ ꢀO distance of 2.783 A. Such
2
2
2
+
‘
‘secondary bonding” interactions are common in Cu
bimetallic units with similar metal–metal contact distances.
coordination complexes [21].
[Cu (pim) (dpa) ] slabs stack along the a crystal direc-
2
2
2
In turn, Cu2 atoms are connected into 1-D [Cu(pim)]n
single chains via tethering pim-A dianionic units
Fig. 6B), which adopt a spread out gauche–anti–anti–
tion via N–Hꢀ ꢀ ꢀO hydrogen bonding interactions between
the central amine functional groups of dpa-B ligands and
unligated carboxylate oxygen atoms of type O5 within
the pim-B dianions, which project into the interlamellar re-
gions (Fig. 8). The closest interlayer Cu–Cu contact dis-
(
gauche conformation (torsion angles = 77.2°, 177.3°,
1
73.0°, 68.7°) with a bis-monodentate bis-monodentate
˚
binding mode. Due to the more open conformation, the
tance is 8.549 A.
˚
Cu2–Cu2 distance through pim-A is 10.352 A, almost
Sequestered within and between the coordination poly-
mer layers are discrete hydrogen bonded aqueous chains
of eight water molecules each (O3Wꢀ ꢀ ꢀO2Wꢀ ꢀ ꢀO4Wꢀ ꢀ ꢀ
O5Wꢀ ꢀ ꢀO5Wꢀ ꢀ ꢀO4Wꢀ ꢀ ꢀO2Wꢀ ꢀ ꢀO3W), decorated at each
˚
1
.5 A longer than the pim-B-bridged corresponding Cu1–
Cu1 distance. Abutting [Cu(pim)] single chains are weakly
n
conjoined through long ‘‘4+1” type Cu2ꢀ ꢀ ꢀO1 secondary
2 2
Fig. 6. [Cu (pim) ] ribbons (A) and [Cu(pim)] double chains with long range interactions shown as dashed lines (B) in 2.

S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
829
2 2
Fig. 7. A 2-D slab motif in 2, formed from the junction of parallel 1-D [Cu (pim) ] ribbons and [Cu(pim)] double chains through dpa tethers.
Fig. 8. Stacking of neighboring 2-D slabs in 2. Discrete water molecule chains can be seen coursing within and between the layers. Hydrogen bonding
connectivity for one of these water chains is shown as dashed lines.
O2W position by additional pendant water molecules (type
O1W). Therefore the unligated water molecule substruc-
ture falls into the uncommonly encountered D(8) morpho-
logical classification [22], with a connectivity pattern
resembling that of 2,7-dimethyloctane. The uncoordinated
water molecules are anchored to the coordination polymer
matrix by extensive hydrogen bonding pathways. The
water molecules at the chain termini (O3W) engage in
hydrogen bonding donation to the ligated and unligated
carboxylate oxygen atoms O3 and O2, belonging to two
separate pim-A ligands. Water molecules of type O1W,
serving as ‘‘substituents” on the aqueous chain, link to
the coordination polymer framework by accepting hydro-
gen bonds from the amine units of dpa-A and donating
hydrogen bonds to unligated carboxylate oxygen atoms
O4 and O6, belonging to pim-A and pim-B, respectively.
Finally, water molecules of type O4W are held by hydrogen
bonding donation to unligated carboxylate oxygen
atoms O7, part of pim-B. Metrical parameters for the
supramolecular hydrogen bonding interactions in 2 are
listed in Table 3. According to a calculation performed
with PLATON [23], the incipient void spaces occupied by
the water molecules of crystallization represent 17.6% of
the unit cell volume of 2.

830
S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
4
.4. Structural description of [Ni(pim)(dpp)] (3)
Table 5
Selected bond distance (A) and angle (°) data for 3
˚
#
1
The asymmetric unit of 3 (Fig. 9) contains one divalent
nickel atom, one dpp ligand, and a doubly deprotonated
Ni1–O4
Ni1–N2
Ni1–N1
2.0675(13)
2.0683(15)
2.0747(15)
2.0761(14)
2.1433(15)
2.1530(15)
1.256(2)
1.2659(19)
1.2548(19)
1.2718(18)
N2 –Ni1–N1
92.70(6)
162.48(4)
94.25(6)
97.37(5)
103.60(5)
92.74(6)
159.22(5)
62.22(4)
62.29(5)
159.02(5)
91.13(6)
105.69(5)
90.93(6)
#
1
#2
O4–Ni1–O2
#
1
#2
2
ꢁ
2ꢁ
N2 –Ni1–O2
pim dianion. Due to the chelation of the pim carbox-
ylate termini, the coordination environment about Ni is
best described as a distorted [NiO N ] octahedron; bond
#2
#2
Ni1–O2
Ni1–O1
Ni1–O3
N1–Ni1–O2
#2
#2
O4–Ni1–O1
#
1
#2
4
2
N2 –Ni1–O1
#
2
lengths and angles about Ni are consistent with this
description (Table 5). The two nitrogen donors, which
belong to two different dpp ligands, are arranged in a cis
orientation.
O1–C21
O2–C21
O3–C27
O4–C27
N1–Ni1–O1
#
2
#2
O2 –Ni1–O1
O4–Ni1–O3
#1
N2 –Ni1–O3
N1–Ni1–O3
#
1
#2
Extension of the structure reveals that each Ni atom is
linked to four others, two through dpp linkers and two
O4–Ni1–N2
O4–Ni1–N1
96.80(6)
95.64(5)
O2 –Ni1–O3
#
2
O1 –Ni1–O3
2
ꢁ
through pim dianions, to form a 2-D rhomboid grid
coordination polymer morphology. The torsion angles
across the trimethylene bridge of the dpp ligand (179.4°
and 176.1°) show that the dpp subunit has adopted a
splayed-open anti conformation, providing a through-
Symmetry transformations to generate equivalent atoms: #1 ꢁx ꢁ 1,
y ꢁ 1/2, ꢁz + 3/2; #2 ꢁx + 1, y ꢁ 1/2, ꢁz + 3/2.
4.5. Variable temperature magnetism
˚
ligand Ni–Ni contact distance of 13.42 A. The bis-bridg-
To probe possible spin communication, samples of 1 and
2 were subjected to variable temperature magnetic study.
For 1, the v T value at 300 K was 1.23 cm K mol . This
is slightly higher than predicted for a spin-only uncoupled
Ni d S = 1 ion, indicative of anisotropy. The v T value
remained largely constant to 60 K, whereupon it began to
decrease, reaching a value of 1.08 cm K mol at 12 K.
At lower temperatures the v T product dropped precipi-
tously, a sign of possible antiferromagnetic coupling, zero
field splitting, or a cooperative effect of the two phenomena.
The magnetic susceptibility of 1 was modeled using Eq. (1)
[25], which accounts for both magnetic coupling between Ni
centers (H) and zero field splitting (D).
2
ꢁ
ing bischelating pim tethers display a gauche–anti–anti–
anti conformation (torsion angles 71.6°, 171.2°, 173.6°,
3
ꢁ1
m
˚
and 176.2°), providing a Ni–Ni distance of 10.28 A,
˚
2+
8
ꢂ3.1 A shorter than the corresponding through-dpp
m
distance.
˚
3
ꢁ1
The grid apertures in 3, 17.10 ꢃ 15.14 A as measured
by through space Ni–Ni distances, are large enough to
accommodate interpenetration of a second identical
m
[
Ni(pim)(dpp)] 2-D layer (Fig. 10). This stands in marked
n
contrast to 1, which does not display any interpenetration
due to the shorter dpa tethers and resulting smaller grid
mesh size. Within a single grid, the Ni–Ni–Ni angles sub-
tend 78.2°, 78.2°, 79.15° and 112.48°. The closest Ni–Ni
separation between two independent interpenetrated lay-
v T
m
ꢀ
ꢀ
ꢁ ꢁ
˚
2
2
ers is 7.57 A. Layer motifs subsequently stack along the
2Ng b
kðT ꢁ HÞ
ð2kT=DÞ ꢁ ð2kT expðxÞ=DÞ þ expðxÞ
1 þ 2expðxÞ
¼
T
c crystal direction primarily by means of p–p supramolec-
3
˚
ular interactions (3.892(2) A) between dpp pyridyl rings
ð1Þ
within adjacent layers, thus constructing the pseudo 3-D
crystal structure of 3. The closest interlayer Ni–Ni contact
where x = ꢁD/kT.
˚
distance is 7.92 A. Unfortunately, attempts to prepare a
The best fit to the data (Fig. 11) occurred with
2
ꢁ
ꢁ1
copper coordination polymer containing both pim and
dpp resulted either in amorphous products or the known
g = 2.241(2), H = ꢁ1.62(4) K and D = 4.9(1) cm
with
P
P
ꢁ3
2
2
R = 9.55 ꢃ 10 = { [(v T) ꢁ (v T) ] / (v T) ] }.
m
obs
m
calc
m
obs
1
-D chain phase [CuCl(dpp)] [24].
Within the layer structure of 1, the pimelate and dpa
n
Fig. 9. Asymmetric unit of 3 with thermal ellipsoids shown at 50% probability and partial atom numbering scheme. Most hydrogen atoms have been
omitted for clarity.

S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
831
Fig. 10. A view down c of doubly interpenetrated (4,4) layers in 3.
m
Fig. 11. Plot of v T vs T for 1-Ni. The calculated fit to Eq. (1) is indicated as a solid black line.

832
S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
ligands cause Ni–Ni distances that are likely too long for
any significant magnetic communication. Closer Ni–Ni
interactions (ꢂ5.1 A), mediated by hydrogen bonding
Cuꢀ ꢀ ꢀCu contact distances, results in significant differences
in the nature and magnitude of their respective magnetic
interactions [28]. Thus, the overall magnetic susceptibility
behavior can be ascribed to the simultaneous action of
the spin communication within both types of {Cu O }
dimer, thereby greatly complicating any attempts at
modeling. Nevertheless, it is probable that net intradimer
ferromagnetic interactions occur in 2, with an underly-
ing weak interdimer antiferromagnetic superexchange
mechanism.
˚
between the aquo ligands and chelating carboxylate
moieties in adjacent layers, could be the origin of the
observed weak interlayer antiferromagnetic coupling.
Attempted fits using models that accounted for either inter-
layer antiferromagnetic coupling or zero field splitting
alone were much less successful. Hydrogen-bonding pro-
moted magnetic communication between paramagnetic
metal ions has been reported in other coordination poly-
mer materials [26].
2
2
4.6. Thermal analysis of 1–3
The plot of the v T product versus T for 2 (Fig. 12)
m
showed an increase in v T as temperature decreased, a sign
of ferromagnetic interactions within one or both types of
oxygen bridged dimeric Cu units within the coordination
Compound 1-Ni underwent loss of its ligated water mol-
ecule between 250 °C and 320 °C (4.9% mass loss, 4.4%
predicted). Combustion of the organic components ensued,
with a series of mass losses between 350 °C and 600 °C. The
mass remnant of 21% corresponds roughly with the depo-
sition of NiO (18% calcd.). Compound 2, which had appar-
ently lost 2 equiv. of unbound water molecules on standing,
continued to dehydrate between 45 °C and 115 °C (5.5%
mass loss, 6.1% calcd. for 3 equiv. of water). Combustion
of organics commenced at ꢂ250 °C, resulting in likely
m
polymer structure. The v T value reached a maximum of
m
3
ꢁ1
1
.52 cm K mol
at 5.2 K, below which temperature it
began to decrease (see inset of Fig. 12). This low-tempera-
ture behavior can be ascribed to weaker antiferromagnetic
interactions between adjacent {Cu O } dimeric units
2
2
through either the pimelate or dpa tethering ligands.
Unfortunately no Curie–Weiss regime was found in the
variable temperature susceptibility data for 2, even at
higher temperatures. Neither could the data be fit accept-
ably to the Bleaney–Bowers equation [27] for magnetically
interacting Cu(II) dimers, even incorporating an interdimer
parameter (H). It is possible that the presence of two differ-
ent types of {Cu O } dimeric units in 2, with varying
deposition of CuCO at 700 °C (29% mass remnant, 30%
3
theoretical). Compound 3 remains stable until ꢂ320 °C at
which point rapid expulsion of the organic components
occurs. The 22% mass remnant at 600 °C corresponds
loosely to NiO (18% calcd.). TGA traces for 1–3 are
depicted in Figs. S1–S3.
2
2
m
Fig. 12. Plot of v T vs T for 2 (inset shows low temperature data only).

S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
833
5
. Conclusions
(b) X.-M. Zhang, M.-L. Tong, H.K. Lee, X.-M. Chen, J. Solid State
Chem. (2001) 118;
(
c) O.M. Yaghi, H. Li, T.L. Groy, Inorg. Chem. 36 (1997) 4292.
Taking advantage of the conformational flexibility of
[
[
4] (a) For example: S.G. Baca, M.T. Reetz, R. Goddard, I.G. Filippova,
Y.A. Simonov, M. Gdaniec, N. Gerbeleu, Polyhedron 25 (2006) 1215;
(b) H. Han, S. Zhang, H. Hou, Y. Fan, Y. Zhu, Eur. J. Inorg. Chem.
8 (2006) 1594;
the a,x-dicarboxylate pimelate ligand, four two-dimen-
sional organodiimine-containing coordination polymers
have been prepared. Both the pimelate conformation and
the tether length and hydrogen-bonding capability of the
organodiimine component appear to play a significant
structure-directing role, in synergy with coordination
geometry preferences. Use of a longer tethering organodii-
mine promotes the formation of rhomboid grids with lar-
ger apertures, resulting in an interpenetrated structure.
The lowered coordination number at the copper centers
in 2, as opposed to 1 and 3, promotes a double slab struc-
ture with {Cu O } dimers that exhibit apparent ferromag-
(
c) W. Mori, S. Takamizawa, C.N. Kato, T. Ohmura, T. Sato,
Micropor. Mesopor. Mater. 73 (2004) 15.
5] (a) For example: S. Zang, Y. Su, Y. Li, Z. Ni, Q. Meng, Inorg. Chem.
4
(b) L. Wang, M. Yang, G. Li, Z. Shi, S. Feng, Inorg. Chem. 45 (2006)
2474;
(
5 (2006) 174;
c) S. Wang, Y. Hou, E. Wang, Y. Li, L. Xu, J. Peng, S. Liu, C. Hu,
New J. Chem. 27 (2003) 1144.
[
[
6] (a) For example: D. Ghoshal, A.K. Ghosh, G. Mostafa, J. Ribas,
N.R. Chaudhuri, Inorg. Chim. Acta 360 (2007) 1771;
(b) C. Livage, C. Egger, M. Nogues, G. Ferey, Compt. Rend. Acad.
Sci. Ser. Chem. 4 (2001) 221.
7] (a) W.-G. Lu, C.-Y. Su, T.-B. Lu, L. Jiang, J.-M. Chen, J. Am. Chem.
Soc. 128 (2006) 34;
2
2
netic coupling. The differing pimelate conformations
observed in these materials reflect this ligand’s ability to
adjust to the requirements imposed by the metal coordina-
tion geometry and the supramolecular environment. Inves-
tigation of long-chain a,x-dicarboxylate coordination
polymers incorporating kinked or flexible organodiimines
remains a fruitful area of synthetic exploration in our lab-
oratory, and further results will be reported in due course.
(
(
b) S. Horike, R. Matsuda, S. Kitagawa, Stud. Surf. Sci. Cat. 156
2005) 725;
(c) C. Qin, X.-L. Wang, Y.-G. Li, E.-B. Wang, Z.-M. Su, L. Xu, R.
Clerac, Dalton Trans. (2005) 2609;
(
(
(
(
d) Y.-Q. Zheng, E.-R. Ying, Polyhedron 24 (2005) 397;
e) S.K. Ghosh, J. Ribas, P.K. Bharadwaj, Crystal Growth Des. 5
2005) 623;
f) X.-Z. Sun, Y.-F. Sun, B.-H. Ye, X.-M. Chen, Inorg. Chem.
Acknowledgements
Commun. 6 (2003) 1412.
[
[
8] L. Xu, G.-C. Guo, B. Liu, M.-S. Wang, J.-S. Huang, Inorg. Chem.
Commun. 7 (2004) 1145.
9] H.-P. Jia, W. Li, Z.-F. Ju, J. Zhang, Eur. J. Inorg. Chem. (2006) 4264.
The authors gratefully acknowledge Michigan State
University for financial support of this work.
We thank Dr. Rui Huang for elemental analysis and
David Martin and Lindsey Johnston for the acquisition
of the infrared spectra. SDG.
[
10] B. Chen, C. Liang, J. Yang, D.S. Contreras, Y.L. Clancy, E.B.
Lobkovsky, O.M. Yaghi, S. Dai, Angew. Chem., Int. Ed. 45 (2006)
1390.
[11] (a) L.-S. Long, Y.-R. Wu, R.-B. Huang, L.-S. Zheng, Inorg. Chem. 43
(
(
2004) 3798;
b) R.-F. Hu, Y. Kang, J. Zhang, Z.-J. Li, Y.-Y. Qin, Y.-G. Yao, Z.
Appendix A. Supplementary material
Anorg. Allgem. Chem. 631 (2005) 3053;
c) Y.-Q. Zheng, J.-L. Lin, Z.-P. Kong, Inorg. Chem. 43 (2004) 2590.
(
CCDC 652276, 652277, 652278 and 652279 contain the
supplementary crystallographic data for compounds 1-Ni,
-Co, 2 and 3. 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, Cambridge CB2 1EZ, UK; fax: (+44) 1223-
36-033; or e-mail: deposit@ccdc.cam.ac.uk. Supplemen-
tary data associated with this article can be found, in the
online version, at doi:10.1016/j.poly.2007.11.006.
[12] M.R. Montney, S. Mallika Krishnan, N.M. Patel, R.M. Supkowski,
R.L. LaDuca, Crystal Growth Des. 7 (2007) 1145.
[13] M.R. Montney, S. Mallika Krishnan, R.M. Supkowski, R.L.
LaDuca, Inorg. Chem. 46 (2007) 7362.
1
[14] P.J. Zapf, R.L. LaDuca, R.S. Rarig, K.M. Johnson, J. Zubieta,
Inorg. Chem. 37 (1998) 3411.
[15] SAINT, Software for Data Extraction and Reduction, Version 6.02,
Bruker AXS, Inc., Madison, WI, 2002.
3
[16] SADABS, Software for Empirical Absorption Correction, Version 2.03,
Bruker AXS, Inc., Madison, WI, 2002.
[17] G.M. Sheldrick, SHELXTL, Program for Crystal Structure Refinement,
University of Gottingen, Gottingen, Germany, 1997.
References
[18] M. Kurmoo, C. Estournes, Y. Oka, H. Kumagai, K. Inoue, Inorg.
Chem. 44 (2005) 217.
[
1] (a) For example: J.L.C. Roswell, O.M. Yaghi, Angew. Chem., Int.
Ed. Engl. 44 (2005) 4670;
[19] R.D. Shannon, Acta Crystallogr., Sect. A 32 (1976) 751.
[20] A.W. Addison, T.N. Rao, J. Chem. Soc. Dalton Trans. (1984) 1349.
[21] L. Yi, L.-N. Zhu, B. Ding, P. Cheng, D.-Z. Liao, Y.-P. Zhai, S.-P.
Yan, Z.-H. Jiang, Trans. Met. Chem. 29 (2004) 200.
[22] (a) L. Infantes, S. Motherwell, CrystEngComm 4 (2002) 454;
(b) L. Infantes, J. Chisholm, S. Motherwell, CrystEngComm 5 (2003)
480.
[23] A.L. Spek, PLATON, A Multipurpose Crystallographic Tool, Utrecht
University, Utrecht, The Netherlands, 1998.
[24] E. Tang, Y.-M. Dai, S. Lin, Acta Crystallogr., Sect. E 60 (2004)
m1095.
(b) M. Kondo, T. Okubo, A. Asami, S.-I. Noro, T. Yoshitomi, S.
Kitagawa, T. Ishii, H. Matsuzaka, Angew. Chem., Int. Ed. Engl. 38
(
(
1999) 140;
c) A.C. Sudik, A.R. Millward, N.W. Ockwig, A.P. Cote, J. Kim,
O.M. Yaghi, J. Am. Chem. Soc. 127 (2005) 7110.
2] (a) For example: J.S. Seo, D. Whang, H. Lee, S.I. Jun, J. Oh, Y.J.
Jeon, K. Kim, Nature 404 (2000) 982;
[
[
(b) A. Cingolani, S. Galli, N. Masciocchi, L. Pandolfo, C. Pettinari,
A. Sironi, J. Am. Chem. Soc. 127 (2005) 6144.
3] (a) For example: Q.-R. Fang, G.-S. Zhu, M. Xue, J.-Y. Sun, S.-L.
Qiu, L. Shi-Lun, Dalton Trans. (2006) 2399;
[25] B. Chen, F. Jiang, L. Han, B. Wu, D. Yuan, M. Wu, M. Hong, Inorg.
Chem. Commun. 9 (2006) 371.

834
S. Mallika Krishnan et al. / Polyhedron 27 (2008) 821–834
[
26] (a) Y. Xie, Q. Liu, H. Jiang, C. Du, X. Xu, M. Yu, Y. Zhu, New J.
Chem. 26 (2002) 176;
(d) X. Ren, Y. Chen, C. He, S. Gao, J. Chem. Soc., Dalton Trans.
(2002) 3915;
(
b) T.K. Paine, T. Weyhermuller, K. Wieghardt, P. Chaudhuri, Inorg.
Chem. 41 (2002) 6538;
c) C. Desplanches, E. Ruiz, A. Rodriguez-Fortea, S. Alvarez, J. Am.
Chem. Soc. 124 (2002) 5197;
(e) H. Kumagai, C.J. Kepert, M. Kurmoo, Inorg. Chem. 41 (2002)
3410.
[27] B. Bleaney, K.D. Bowers, Proc. R. Soc. London A 214 (1952) 451.
[28] O. Khan, Molecular Magnetism, VCH Publishers, New York, 1993.
(