Construction of metal-organic frameworks: Versatile behaviour of a ligand containing mono-and bidentate coordination sites

Article abstract of DOI:10.1002/chem.201101998

Five new coordination polymers based on a new 2,2′-bipyridine derived ligand N,N'-bis(pyridin-4-yl)-2,2′-bipyridine-5,5′-dicarboxamide (=L) are reported herein. Isostructural three-dimensional coordination polymers with a rare (4,6)-connected network of {

Full text of DOI:10.1002/chem.201101998

FULL PAPER
DOI: 10.1002/chem.201101998
Construction of Metal–Organic Frameworks: Versatile Behaviour of a Ligand
Containing Mono- and Bidentate Coordination Sites
Tia Jacobs and Michaele J. Hardie*[a]
Abstract: Five new coordination poly-
mers based on a new 2,2’-bipyridine de-
rived ligand N,N’-bis(pyridin-4-yl)-2,2’-
bipyridine-5,5’-dicarboxamide (=L) are
reported herein. Isostructural three-di-
mensional coordination polymers with
mixture of Cu
in complexes
(H2O)18}1 (1),
G
R
N
ACHTUNGTRENNUNG(NO3)10·-
R
G
G
ACHTUGNTRENN(UNG NO3)2 with L in com-
Keywords: 2,2’-bipyridine
· ACTHNGUTER(NNUG 4,6)-
connected topology · crystal struc-
ture · coordination polymers · met-
al–organic frameworks
a
rare (4,6)-connected network of
3A
{44.62} {46.89}2 topology were synthes-
ised from Cu(NO3)2, Zn(NO3)2 or a
CHTUNGTRENNUNG
A
ACHTUNGTRENNUNG
Introduction
secondary supramolecular interactions (specifically coordi-
nation).[9]
The synthesis of coordination polymers has evoked an im-
mense amount of recent interest.[1] The main focus has been
on the construction of microporous coordination polymers
due to their potential as gas storage materials,[2] nano-scale
reaction vessels, and their catalytic[3] and magnetic proper-
ties.[4] It has become evident that judicious choice of metal
centre and bridging ligand can afford infinite two- and
three-dimensional networks that feature the desired charac-
To this end we have been investigating the use of deriva-
tives of 2,2’-bipyridine with additional monodentate coordi-
nation ability to prepare coordination polymers. ML3 tris-
AHCTUNGTREGcNNUN helate moieties can be coordinated further with additional
pendant metal binding groups to afford two- or three-di-
mensional nets. While pursuing this design strategy towards
the assembly of rigid coordination polymers for porous ap-
plications, we have synthesised five new framework com-
plexes featuring the new ligand N,N’-bis(pyridin-4-yl)-2,2’-
bipyridine-5,5’-dicarboxamide (=L). The frameworks are a
teristics andACHTUNGTRENNUNG
(/or) interesting structural topologies.[5] The po-
tential of 4,4’-bipyridine as a rigid pillar (linear connecting
ligand) in the construction of coordination polymers has
long been realised and this ligand has seen widespread use
as bridging ligand in the synthesis of two- and three-dimen-
sional coordination polymers.[6] On the other hand, the use
of 2,2’-bipyridine as chelating ligand as well as bridging
ligand in the construction of three-dimensional coordination
polymers have not been fully realised. Known examples
stem from a few networks assembled from multicarboxy-
2,2’-bipyridines, which exploit the anionic bis(carboxylato)
moiety.[7,8] We, therefore, wanted to further investigate the
potential of the 2,2’-bipyridine moiety as a building block
for coordination polymers, firstly since the 2,2’-bipyridine
metal trischelate structural node has an inherent diverging
topology, and secondly since the 2,2’-bipyridine core could
be decorated with a variety of pendant groups suitable for
three-dimensional network {[M5L6]}1, which could be self-
assembled by using Cu
(H2O)18}1, 1), Zn(NO3)2 (complex {[Zn5L6]·
(H2O)18}1, 2) or a mixture of Fe(BF4)2 and Cu(NO3) (com-
plex {[FexCuyL6]·(NO3)10·A(H2O)18}1, 3); along with two close-
ly related two-dimensional sheets in complexes
{[CoLCl2]·DMF}1 (4) and {CdL(NO3)2}1 (5). The synthesis,
A
ACHTUNGTRENNUNG(NO3)10·-
A
R
ACHTUNGTRENNUNG
A
R
ACHTUNGTRENNUNG
A
CHTUNGTRENNUNG
AHCTUNGTRENNUNG
crystal structures and behaviour of two of these frameworks
towards guest solvent loss will be discussed, focusing on one
example of each of the two topologies.
[a] Dr. T. Jacobs, Dr. M. J. Hardie
School of Chemistry, University of Leeds
Woodhouse Lane, Leeds, LS2 9JT (UK)
Fax : (+44)113 343-6565
Results and Discussion
Synthesis and crystal structure of N,N’-bis(pyridin-4-yl)-2,2’-
bipyridine-5,5’-dicarboxamide, L: The ligand was synthes-
ised in two steps from 5,5’-dimethyl-2,2’-bipyridine. By using
E-mail: m.j.hardie@leeds.ac.uk
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201101998.
Chem. Eur. J. 2012, 18, 267 – 276
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
267

a literature procedure the 5,5’-dimethyl-2,2’-bipyridine can
readily be oxidised to the 5,5’-dicarboxylic acid-2,2’-bipyri-
dine with chromic acid (K2Cr2O7 in H2SO4). Thereafter, the
di-acid was converted to the acid chloride in situ with thio-
nyl chloride, followed by treatment with 4-aminopyridine to
afford L. The ligand was recrystallised from dimethyl sulfox-
ide (DMSO) to afford single crystals, the structures of which
were elucidated by single-crystal X-ray diffraction in the tri-
discussed here, but are shown in Figures S1 and S2 in the
Supporting Information.
Synthesis of 1–5: Diffraction quality single-crystals of the
networks were obtained from the treatment of L and the
metal salts Cu
Fe(BF4)2/Cu(NO3)2 (complex 3), CoCl2 (complex 4) and Cd-
(NO3)2 (complex 5). Complexes 1–4 were obtained from di-
ACHTUNTGRENNG(U NO3)2 (complex 1), ZnACHTUNGTRNE(NUGN NO3)2 (complex 2),
A
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
¯
clinic space group, P1. This revealed half of a ligand and
methylformamide solutions (in a 3:1 ligand-to-metal ratio)
with diethyl ether as anti-solvent (network 4 crystallised
without diethyl ether), while network 5 was afforded from
an N-methyl-2-pyrrolidone solution, again with the slow dif-
fusion of diethyl ether.
one DMSO molecule per asymmetric unit. The bipyridine
moiety of the ligand is co-planar with the nitrogen atoms in
the trans positions. Each ligand hydrogen bonds to two
ꢀ
DMSO molecules through N H···O interactions (D···A:
2.876(3) ꢁ) between the amide and S=O moieties
(Figure 1). The overall structure consists of the ternary hy-
drogen bonded units packing through edge-to-face p interac-
tions. One interaction connects the ternary units along the
stacking axis (crystallographic b axis; C···centroid 2.904 ꢁ),
while the second interaction connects neighbouring stacks
(C···centroid 3.004 ꢁ). Two more single crystal structures of
the ligand have been obtained serendipitously from crystalli-
sation trials, a hydrate, and pure ligand; these will not be
Structure of {[Cu5L6]·ACTHNUTRGENNUG(NO3)10·CAHTUNGTREN(NUGN H2O)18}1 (1): The atomic
numbering and connectivity of 1 are shown in Figure 2. The
structure was solved and refined in the body centred cubic
space group I432, and was shown to be a three-dimensional
coordination polymer containing two distinct copper centres.
Cu(1) is chelated by three bipyridine moieties in an octahe-
dral coordination geometry resulting in delta (D, right-
ꢀ
handed) chirality (Cu(1) N(1)=2.117(2) ꢁ). All Cu(1) cen-
tres in the crystal structure have this chirality, which indi-
cates that the trischelate enantiomers resolve spontaneously
upon self-assembly into the three-dimensional network.[10]
The bulk sample exists as a racemate. Cu(2) has octahedral
geometry, with four monodentate p-pyridine moieties in
ꢀ
square planar positions (Cu(2) N(13)=2.011(2) ꢁ). Two
ꢀ
aqua ligands occupy the axial positions, one at Cu(2)
O(3)=2.310(4) ꢁ, while the second water molecule forms a
ꢀ
long interaction with Cu O distance 2.760(5) ꢁ.
If the unique copper centres are considered as nodes in
the structure, the combination of the two copper coordina-
tion geometries thus afford a three-dimensional (4,6)-con-
nected net. The connectivity as represented by the copper
nodes is illustrated in Figure 3, and is composed of vertex-
linked polyhedral prisms. Each of the stella octangula
prisms has eight Cu(1) centres at its vertices, and three fac-
4-pyridyl moieties emanate from each of these Cu(1) units
to bind to a different symmetry-related square planar Cu(2)
centre. Each Cu(2) is bound by four pyridyl groups from dif-
ferent Cu(1) nodes, to create a cube-like or stella octangula
construction (Figure 3a and b). Each stella octangula is
linked to eight others through its Cu(1) centres to create the
vertex-linked network (Figure 3c). Other structural types in-
volving coordination networks constructed from the metal-
vertex-sharing of large polyhedral assemblies are known.
For example, the vertex-linked M6L4 octahedra from 2,4,6-
tris(4-pyridyl)-1,3,5-triazine first reported as two interpene-
trating nets by Robson et al.,[11a] and more recently the non-
interpenetrated version reported by Fujita et al. by virtue of
a change of metal centre.[11b] These two structures are also
reminiscent of two other three-dimensional 3,4-connected
networks, that is, a covalent organic framework (COF-108)
described by Yaghi et al.,[11c] in which the octahedra are
joined by shared vertices of tetrahedral carbons, and a
metal–organic framework (MOF), HKUST-1, presented by
Figure 1. a) Ellipsoid plots (50% probability) of L·2DMSO, the asym-
ꢀ
metric unit of the structure has been labelled. The N H···O hydrogen
bonds are shown as dashed lines. b) Stacking of the ternary hydrogen
bonded unit shown along the crystallographic b axis. Two symmetry inde-
ꢀ
ꢀ
pendent C H···p interactions are shown as well as one N H···O interac-
tion.
268
www.chemeurj.org
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2012, 18, 267 – 276

Construction of Metal–Organic Frameworks
FULL PAPER
clusters with cyanide bridging
ligands[13a,b] as well as a porous
MOF.[13c,d] In our structure no
interpenetration is seen, and as
a result of the cubic symmetry,
three-dimensional intersecting
channels are formed, as well as
discrete solvent and anion-filled
space
within
the
prisms
(Figure 4). The body diagonal
Cu···Cu distance within the
stella octangula prism is about
28.1 ꢁ, which is also the diago-
nal Cu···Cu distance across each
channel; hence the structure
cannot interpenetrate, as
a
second network would not fit
into the channels.
When water molecules are
omitted the calculated guest-ac-
cessible free space is approxi-
mately 68% per unit cell, and
the Cu(2)···Cu(2) distance (the
width of the discrete cage) is
15.51 ꢁ. Most of the nitrate
anions (per Cu5/6LACHTUNGTRNEGN(U NO3)5/3 for-
mula unit) could be located in
the electron density map, with
one sixth of a nitrate missing
from the asymmetric unit. Four
water molecules could be mod-
elled per formula unit, which
correlates with elemental and
thermal analysis of air-dried
crystals; these showed that a
total of three molecules of
water are present per formula
unit (Cu5/6L1ACHTUNGTRENUNG(NO3)5/3). This indi-
cates the spontaneous loss of
one water molecule. One of the
nitrate anions in the asymmet-
ric unit is seen to be encapsulat-
ed in the interstice between the
three fac ligand arms, and ac-
cepts three hydrogen bonds
Figure 2. Ellipsoid plots showing: a) the octahedral coordination geometry around Cu(1), and b) the square
planar coordination geometry of the monodentate p-pyridine moieties around Cu(2); only one half of the
ligand as present in the asymmetric unit has been shown and the aqua ligands have been omitted for clarity.
ꢀ
from each of the N H donors,
Williams et al.,[11d] in which octahedra are joined by dicop-
per carboxylate paddlewheels. Polyhedra can also be linked
into networks through other, non-vertex-sharing, mecha-
nisms. For example, the metal–organic framework of trun-
cated cuboctahedra linked by the use of tritopic ligands re-
ported by Eddauodi and colleagues;[11e] for a recent review
on the subject see Zaworotko et al.[11f]
with N···O=2.943(3) ꢁ (Figure 5). This phenomena has also
been noted by Janiak et al., who found that metal trische-
lates of 5,5’-dicarbamate-2,2’-bipyridine show sulfate–anion
binding in the pocket afforded by the three ligand arms.[14]
A further interesting point is the relative scarceness of
structures reported to have been solved in the space group
I432. Only four examples of supramolecular and MOF sys-
tems in this space group are known, these include a nano-
meter sized M6L8 cage reported by Ueyama and co-workers,
an isostructural MOF series based on g-cyclodextrin by
Stoddart and colleagues, a MOF based on a dicarboxylate
The Schlꢂfli symbol for the network found in complex 2 is
3ACHTUNGTRENNUNG
{44·62} {46·89}2, and the topological type, soc.[12] To the best of
our knowledge this is a very rare topology in crystals, and
has only been observed (classified) in a series of inorganic
Chem. Eur. J. 2012, 18, 267 – 276
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
269

M. J. Hardie and T. Jacobs
Figure 5. A depiction of the enclathrated nitrate anion in ball-and-stick
representation and the trischelate shown in capped-stick representation,
all hydrogen atoms not engaged in hydrogen bonding have been omitted.
Structures
of
{[Zn5L6]·
G
(H2O)18}1
(2)
and
{[FexCuyL6]·
N
10 A(H2O)18}1 (3; where x+y=5): These
two networks are isostructural with 1 (see the Supporting
Information for a short summary of relevant bond lengths).
The existence of a mixture of iron and copper in network 3
was confirmed by energy-dispersive X-ray spectroscopy
(EDX). Five crystals were randomly picked for analysis, and
iron atomic percentages were semi-quantitatively deter-
mined to be in the range 6.60 to 32.93% with an average of
16.14% (if the sum of iron and copper is considered to be
100%) indicating a range of solid solutions are formed. Het-
erometallic coordination polymers are known and often in-
volve a multitopic ligand approach in which “metallo-li-
gands” (coordination complexes) possess functional groups
for further metal coordination.[17] The formation of hetero-
metallic solid solutions of coordination polymers is rarer,
but has been previously reported from solution crystallisa-
tions,[18a,b] as observed here, as well as from mechano-chemi-
cal synthesis.[18c]
Figure 3. a) The stellated octahedron consisting of eight octahedral cor-
ners from Cu(1) centres (light blue) and six square planar Cu(2) sites
(purple). b) The stellated octahedron as depicted in (a), presented in
capped-stick and CPK colours (except for copper centres). On the Cu(1)
corners, the parts of the ligand extending to the next octahedra have
been omitted, hydrogen atoms have also been omitted. c) The
Cu(1)···Cu(2) connectivity in the three-dimensional network of cubes, in
which the blue nodes are the trischelate copper node, and the purple
colour represents the square planar copper nodes. The body centred
cubic framework is constructed from corner-sharing octahedral units.
Structure of {[CoLCl2]·DMF}1 (4): The atomic numbering
and connectivity of 4 is shown in Figure 6a. The structure
was determined to be in the monoclinic space group P21/c.
One unique cobalt atom exists in an octahedral coordination
Figure 4. Space-filling diagrams of the network viewed along: a) [100]
(equivalent views along [010] and [001]), and b) [111].
ꢀ
environment (Figure 6b) with two chloride ligands (Co(1)
ꢀ
Cl(2) and Co(1) Cl(3), 2.442(1) and 2.446(1) ꢁ, respective-
ly) and one chelating bipyridine moiety in the equatorial
ꢀ
ꢀ
ligand by Jeong et al., as well as a hydrogen-bonded molecu-
lar assembly of calix[4]resorcinarenes.[15] There have also
been a small number of reports of molecular complexes in
this space group, for example, gallium and indium alkoxo-
metalates and a hexanuclear nickel complex.[16]
plane (Co(1) N(1) and Co(1) N(16), 2.188(2) and
2.217(2) ꢁ, respectively).
Two 4-aminopyridine pendant groups occupy the remain-
ing trans positions, with Co(1) N(13)=2.216(2) ꢁ and
Co(1) N(28)=2.239(2) ꢁ. When the asymmetric unit of the
network is considered, it is seen that the ligand is twisted,
with one terminal 4-pyridyl moiety disordered over two po-
ꢀ
ꢀ
270
www.chemeurj.org
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2012, 18, 267 – 276

Construction of Metal–Organic Frameworks
FULL PAPER
Figure 6. a) Asymmetric unit of 4 shown in an ellipsoid plot. b) A stick
diagram showing the octahedral coordination geometry around Co(1),
where the one 4-pyridyl arm is disordered over two positions.
sitions. The coordinated 2,2’-bipyridine moiety and cis chlor-
ides are seen to occupy a slightly distorted square planar ge-
ometry around the cobalt. One DMF molecule could be lo-
cated in the electron density map, and is seen to hydrogen
bond via the C=O bond to the amide proton of the ligand
(D···A=2.807(3) ꢁ).
The combination of the bridging nature of the ligand via
its pendant 4-aminopyridine groups and the chelating nature
of the 2,2’-bipyridine moiety results in an overall two-dimen-
sional network (Figure 7a). The two-dimensional sheet is
parallel to the (010) plane, and neighbouring sheets are re-
lated by inversion symmetry, creating an off-set packing ar-
rangement along [100] (Figure 7b).
Figure 7. a) A diagram depicting the resulting two-dimensional network
of 4. b) The solvent-filled channels along [100] that result from the stack-
ing of the two-dimensional networks.
Degassing, thermal stability and powder diffraction of 1 and
4: As the five networks that were obtained in this study
mainly have two topologies, we selected one example of
each topology for further investigation. These were
Structure of {CdLACHTUNGTRENNUNG(NO3)2}1 (5): This structure was solved
and elucidated in the space group P21 and determined to be
identical to 4 in terms of the two-dimensional sheet motif.
The asymmetric unit is shown in Figure 8a, and once again
the ligand is seen to be twisted with the one half of the bi-
pyridine core displaying disorder. The metal centre is cadmi-
um in this instance, and has as with 4, an octahedral coordi-
nation environment consisting of a chelating bipyridine and
two nitrate anions (one terminal and one chelating nitrate)
in the equatorial positions, and two 4-aminopyridine moiet-
ies in the trans positions.
{[Cu5L6]·ACTHUNGERTUNN(G NO3)10·CATHUNGTNERUN(GN H2O)18}1 (1) and {[CoLCl2]·DMF}1 (4).
The bulk sample of 1 was subject to powder diffraction,
and showed a good correlation with that of a powder trace
simulated from the single-crystal structure (Figure 10b).
Thermogravimetric analysis (TGA) of air-dried crystals of 1
only showed a small weight loss of about 9.5% up to 2008C,
shortly after which the material decomposed, with an onset
temperature of 263.368C (Figure 10a). The 9.5% weight
loss translates to approximately three molecules of water
per formula unit (Cu5/6L1ACHTUNTGRNEUNG(NO3)5/3), which is in agreement
In this structure, the two-dimensional layers are parallel
to the bc plane (Figure 9a) and stacked along the crystallo-
graphic a axis, whereas in 4 neighbouring layers were related
by inversion symmetry (Figure 9b). This generates channels
along the [100] direction and no solvent could be modelled
in these channels from the electron density map.
with the elemental analysis. We anticipate that no DMF
molecules are present, since these would be expected to
reside in the open channels of the structure, and could spon-
taneously desorb. From the crystal structure, we know, how-
ever, that several water molecules are present within the dis-
crete volume inside the prism. Crystals of 1 were immersed
in ethanol for two hours in an attempt to exchange the
Chem. Eur. J. 2012, 18, 267 – 276
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
271

M. J. Hardie and T. Jacobs
Figure 8. a) Asymmetric unit of 5 shown in an ellipsoid plot. b) A stick
diagram showing the octahedral coordination geometry around Cd(1),
where one of the pyridyl rings in the 2,2’-bipyridine core is disordered
over two positions.
Figure 10. a) Thermal analysis, and b) powder diffraction data for 1.
water molecules for ethanol molecules. The blue colour of
the crystals remained unchanged during this solvent ex-
change and TGA showed a slightly reduced weight loss of
7.4%, which can be attributed to approximately 2.5 mole-
cules of water or one molecule of ethanol per formula unit.
Crystals of 1 were also subject to evacuation at 1008C for
3 days, which resulted in a dark green powder, and hereafter
TGA showed a significantly reduced weight loss of about
3.4% (~1 molecule water). Powder diffraction data of the
degassed material compares very well with the as-synthes-
ised sample, however, with reduced crystallinity.
The bulk phase purity of 4 was determined to be homoge-
neous when powder diffractograms of the as-synthesised
material were compared to a simulated diffractogram for
the single-crystal structure (Figure 11b). TGA of air-dried
crystals of 4 revealed that the loss of the DMF guest mole-
cules occurs from room temperature, and the weight loss
AHCTUNGTREG(NNUN ~33.6%) corresponds to four molecules of DMF formula
unit (CoCl2L). TGA and differential scanning calorimetry
(DSC) also show that the material decomposes with an
onset temperature of 395.758C. Subsequently we attempted
to desorb a sample of 4 by evacuating it for 3 days. Even
though the sample changed from an orange to a green
powder, TGA still showed a significant initial weight loss
between 20 and 2008C (~20.6%) representing two mole-
Figure 9. a) Stacking of the two-dimensional layers of 5 viewed along the
stacking direction [100]. b) A comparison of 4 and 5, as viewed along
[010] for both structures.
272
www.chemeurj.org
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2012, 18, 267 – 276

Construction of Metal–Organic Frameworks
FULL PAPER
therefore, capable of complete desorption and resorption of
DMF guest molecules accompanied by a reversible phase
change.
Porosity of degassed phases: Sorption studies were per-
formed by probing the behaviour of these frameworks to-
wards nitrogen at ꢀ196.158C (liquid nitrogen) by using a
ASAP2020 (accelerated surface area and porosimetry
system). The porosity of 1 was investigated after the activa-
tion of the sample by immersing it in ethanol for 3 days.
After this the material was further activated on the degas
port of the gas sorption instrument at 808C for 20 h. The
sorption experiment was immediately carried out, and
showed that the sample was not porous to nitrogen
(Figure 12). Compound 4 was activated by evacuation at
2008C for 4 h prior to gas sorption studies. The obtained
sorption isotherms showed that the sample is not permeable
to nitrogen, with the rise in soprtion near saturation pres-
sure due to capillary condensation in the sample.
Figure 11. a) Thermal analysis, and b) powder diffraction data for 4.
cules of DMF. The powder diffractogram of this evacuated
material also showed good correlation with that of 4. This
material was then subjected to further evacuation at 608C
for 7 days, TGA once again showed weight loss (~14.0%).
At this point it was evident that very harsh conditions would
have to be employed to completely rid the network of its
DMF guests. A solvent-exchange strategy was then applied,
and the as-synthesised material was soaked in chloroform
for an hour. The TGA now obtained showed a much re-
duced weight loss of approximately 8% (TGA of chloro-
form-exchanged samples that were subject to evacuation,
and heating under evacuation showed the same weight
losses). From powder diffraction it can clearly be seen that
this chloroform-exchanged material (orange-brown colour)
exhibits a new phase; this can either be due to a scissoring
of the two-dimensional square grid, or the movement of the
two-dimensional layers relative to each other to form a non-
porous staggered array (a combination of these two network
rearrangements can also be envisaged). In a quick test to
see if the DMF guest phase can be regenerated, the chloro-
form exchanged material was exposed to DMF vapour for a
few days and then analysed by TGA and powder diffraction.
The thermogram and diffractogram showed that DMF was
indeed taken up again by the material, and these are shown
along with the initial phase transformation from DMF-
loaded to empty host phases in Figure 11b. This network is,
&
*
Figure 12. Sorption and desorption of samples of 1 ( ) and 4 ( ) de-
gassed with heating.
Conclusion
The new ligand N,N’-bis(pyridin-4-yl)-2,2’-bipyridine-5,5’-di-
carboxamide (L) features both chelating and monodentate
metal-binding sites. Trischelate and monochelate metal com-
plexes of L have been shown to be effective structural nodes
for the construction of three- or two-dimensional coordina-
tion polymer materials. The three-dimensional structure has
3ACTHNUTRGNEUNG
a highly unusual {44·62} {46·89}2 or soc topology type, which
can also be described as vertex-sharing stella octangula
prisms. It is a structure that cannot interpenetrate, thus max-
imising cavities and channels, and features both orthogonal
nano-sized channels and large internal cavities of the prisms.
Grid-like two-dimensional coordination polymers are
formed from monochelate complexes and these show rever-
sible dynamic behaviour on solvent exchange. The use of
simple 2,2’-bipyridine chelate complexes with additional
metal binding sites on the ligands as structural nodes or
Chem. Eur. J. 2012, 18, 267 – 276
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
273

M. J. Hardie and T. Jacobs
crystals were then rinsed with a small amount of ethanol and allowed to
air dry. After being air-dried 65 mg was obtained, this translates to 36%
yield if a molecular formula of [Cu5/6LAHCUTNRGEN(NUG NO3)5/3]ACHTUNGTERN(NUGN H2O)3 is considered (as
building units for coordination polymers remains relatively
unexplored. These materials illustrate that this is an alterna-
tive approach to generating new potentially porous materi-
als, and this is the subject of ongoing work.
determined from thermogravimetric analysis). An air-dried sample was
submitted for elemental analysis. IR (ATR): n˜ =3271 (brs), 1699 (s),
1594 (s), 1514 (s), 1476 (m), 1423 (s), 1332 (s), 1213 (s), 1126 (s), 1014 (s),
898 (s), 829 (s), 755 cmꢀ1 (s); elemental analysis calcd (%) for Cu5/6
-
ACHUTNGRTENN(GUN NO3)5/3C22H16N6O2·3H2O: C 43.55, H 3.65, N 17.70; found: C 43.90, H
3.45, N 17.45.
Experimental Section
Synthesis of 2: ZnACHTUNGTRNEG(UN NO3)2·6H2O (0.6 mg, 0.002 mmol) was dissolved in
DMF (0.2 mL) and added to a solution of L (2.4 mg, 0.006 mmol) in
DMF (1 mL). Diisopropyl ether was diffused into this solution to afford
colourless block-shaped crystals; yield: 32%. A sample for elemental
analysis was dried under vacuum at 1008C for 15 h. IR (ATR): n˜ =3182
(brm), 1588 (s), 1289 (s), 1210 (s), 1123 (s), 1039 (s), 899 (s), 831 cmꢀ1
General: IR spectra were measured for compounds as solid-state samples
on a Perkin–Elmer FTIR spectrometer. Elemental analyses were per-
formed at the micro-analytical laboratory at the University of Leeds.
ESMS were recorded by using Micromass LCT or Bruker MicroTOFFo-
cus mass spectrometers. NMR spectra were recorded on Bruker Avance
500 MHz spectrometer by using 5 mm probes. The 1H NMR spectrum
was referenced relative to the solvent peak: [D6]DMSO, d=2.6 ppm. Si-
multaneous thermogravimetric analysis and differential scanning calorim-
etry were carried out on a TA instruments SDT Q600 by using a
58Cminꢀ1 heating rate under a nitrogen atmosphere with a 50 mLminꢀ1
flow rate. Volumetric sorption was carried out on a Micromeritics ASAP
2020 instrument. X-ray powder diffraction experiments were carried out
on a Bruker D8 instrument by using Cu-Ka radiation (l=1.5418 ꢁ).
EDX was performed on a Jeol JSM-6610 LV instrument, coupled to an
INCA EDS system. Unless otherwise stated, reagents were obtained
from commercial sources and used as received. 2,2’-bipyridine-5,5’-dicar-
boxylic acid was prepared according to a literature procedure.[19]
(s);
elemental
analysis
calcd
(%)
for
Zn5/6ACHTUNGTRENNUNG(NO3)5/
3C22H16N6O2·2/3 H2O·2/3 C3H7NO: C 46.87, H 3.61, N 18.98; found: C 47.20,
H 3.70, N 18.10.
Synthesis of 3: L (1.2 mg, 0.003 mmol) was dissolved in DMF (1 mL) and
Fe
ACHTUNGTRENNUNG
lowed by CuACHTUNGTRENNNUG
After a few weeks grey crystals were formed; yield: 30%. A sample for
elemental analysis was dried under vacuum at 1508C for 15 h. IR (ATR):
n˜ =3383 (brs), 1652 (s), 1601 (s), 1514 (s), 1478 (s), 1334 (s), 1212 (s),
1126 (s), 1031 (s), 900 (s), 838 cmꢀ1 (s); elemental analysis calcd (%) for
Fe1/12Cu3/4ACTHNUTRGNEUNG
(NO3)5/3C22H16N6O2·3/2 H2O: C 45.63, H 3.31, N 18.54; found: C
45.75, H 3.40, N 17.35.
Synthesis of 4: For SCD a solution of CoCl2·6H2O (0.5 mg, 0.002 mmol)
and L (2.4 mg, 0.006 mmol) in DMF (1 mL) was diffused with diethyl
ether, red crystals were obtained after 5 days.
Synthesis of L (N,N’-bis(pyridin-4-yl)-2,2’-bipyridine-5,5’-dicarboxamide):
2,2’-Bipyridine-5,5’-dicarboxylic acid (450 mg, 1.84 mmol) was activated
by reflux in thionyl chloride (10 mL) until the solution was clear. The
thionyl chloride was removed in situ and the acid chloride was suspended
in dry dichloromethane (~80 mL) and brought to reflux under argon. In
a second flask 4-aminopyridine (432.9 mg, 4.60 mmol) was dissolved in
dry dichloromethane (~30 mL) and dry triethylamine (2.56 mL,
18.40 mmol) was added. The mixture was added dropwise via cannula to
the acid chloride solution while under reflux. Upon complete addition of
the mixture, heating at reflux was continued for a further 30 min, and al-
lowed to cool to room temperature, overnight, with continuous stirring.
The light yellow solid was removed by filtration, washed with dichloro-
methane, water and finally diethyl ether to afford a light yellow coloured
powder. Inspection of the 1H NMR spectrum of the solid revealed a
single compound, therefore, further purification was not performed.
However, the material can be further purified by recrystallisation from a
hot dimethylformamide solution to afford a white-creamy crystalline
solid; yield: 88%; m.p.>3608C; 1H NMR (500 MHz, [D6]DMSO, 258C):
Bulk sample: The synthesis of 4 was easily scaled-up from the crystallisa-
tion. L (118.9 mg, 0.3 mmol) was dissolved in DMF (30 mL) by gently
heating the stirred solution and a solution of CoCl2·6H2O (71.4 mg,
0.3 mmol) in DMF (5 mL) was added slowly. The clear dark green solu-
tion was then allowed to cool to room temperature and after a few days
the orange-red solid that formed was removed by filtration, washed with
DMF and a small volume of ethanol was added to yield an orange-brown
powder. After being air-dried 190 mg was obtained, this translates to
78% yield if a molecular formula of CoCl2L·4DMF is considered (as de-
termined from thermogravimetric analysis). A sample for elemental anal-
ysis was dried at 708C for 30 h. IR (ATR): n˜ =3262 (brs), 1698 (s), 1596
(s), 1508 (s), 1213 (m), 1125 (s), 1031 (s), 899 (s), 828 (s), 752 cmꢀ1 (s); el-
emental analysis calcd (%) for CoCl2C22H16N6O2·21/2 H2O: C 46.25, H
3.71, N, 14.71; found: C 46.45, H 3.50, N 14.70.
Synthesis of 5: CdACTHUNTRGNE(UNG NO3)2·4H2O (0.6 mg, 0.002 mmol) was dissolved in N-
d=7.80 (dd, 3J
8.538, (m, 6H; NCHCH and NCCHCH), 8.633 (d, J
NCCH), 9.266 (d, 4J
(H,H)=2.3 Hz, 2H; NCHC), 10.884 ppm (s, 2H;
ACHTUNGTRENNUNG ACHTUNGTREN(NNGU H,H)=1.68 Hz, 4H; NCHCH), 8.525–
(H,H)=4.8 and 4J
methyl-2-pyrrolidone (NMP; 0.2 mL) and added to a solution of L
(2.4 mg, 0.006 mmol) in NMP (1 mL). The solution was placed in a
bigger vial containing diethyl ether, and irregular colourless blocks were
visible after a few weeks (crystals could also be obtained from DMF with
diethyl ether diffusion); yield: 37%. A sample for elemental analysis was
dried at 1008C for 15 h. Elemental analysis calcd (%) for
C22H16N8CdO8·1/4 C5H9NO: C 42.46, H 3.00, N 17.35; found: C 42.46, H
2.80, N 17.57; IR (ATR): n˜ =3359 (brs), 1664 (s), 1599(s), 1509 (s), 1425
(s), 1334 (s), 1298 (s), 1212 (m), 1127 (m), 1032 (m), 899 (m), 830 (m),
754 cmꢀ1 (m).
3
AHCTUNGTREG(NNUN H,H)=8.2 Hz, 2H;
ACHTUNGTRENNUNG
NH); IR (ATR): n˜ =3361 (s), 1900 (m), 1739 (w), 1667 (brs), 1591 (brs),
1415 (s), 1295 (brs), 1114 (s), 1025 (s), 991 (s), 896 (s), 855 (s), 821 (s),
758 (s), 724 cmꢀ1 (s); MS (ESI+): m/z (%): 397.14 (100) [M+H+],
199.08 (24) [M+2H+]; HRMS-ToF (ESI+): found: 397.1416 [M+H+],
calcd for C22H17N6O2 397.1408; elemental analysis calcd (%) for
C22H16N6O2·1/4 H2O: C 65.91, H 4.15, N, 20.96; found: C 66.10, H 4.10, N
20.95.
Synthesis of complexes
Crystal structure determinations: Crystals were attached to the end of a
MiTeGen mount by using paratone oil. X-ray data were collected with
MoKa radiation (l=0.71073 ꢁ) on a Bruker Nonius X8 diffractometer
fitted with an Apex II detector, FR591 rotating anode operating at 4 kW
and an Oxford cryosystems cryostream plus cooling system. Data reduc-
tion was carried out by means of a standard procedure by using the
Apex2 software package. When necessary, empirical corrections were
performed by using SADABS. Structures were either solved by direct
methods or Patterson methods by using SHELXS[20] or SIR-2004[21] and
refined by fullmatrix least-squares on F2 by SHELXL,[20] interfaced
through the program X-Seed.[22] In general, all non-hydrogen atoms were
refined anisotropically and hydrogen atoms were included as invariants
at geometrically estimated positions. Diagrams were generated by using
Synthesis of 1: For single-crystal diffraction (SCD): CuACTHNUTRGNEUNG
(NO3)2·21/2 H2O
(0.5 mg, 0.002 mmol) was dissolved in DMF (0.2 mL) and added to a so-
lution of L (2.4 mg, 0.006 mmol) in DMF (1 mL). The vial with DMF so-
lution was placed in a bigger vial containing diethyl ether. After one
week blue-purple octahedral crystals formed.
Bulk sample: L (118.9 mg , 0.3 mmol) was dissolved in DMF (30 mL) by
slight heating and stirring,
a solution of CuACHTNUGTNRUE(GN NO3)2·6H2O (72.8 mg,
0.3 mmol) in DMF (5 mL) was added to the stirring solution. The green
solution was allowed to cool to room temperature and after a few days
the solution is a dark green suspension with blue solid. The green suspen-
sion was decanted from the blue solid, and the blue crystals further
rinsed with DMF to remove the last traces of green material. The blue
274
www.chemeurj.org
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2012, 18, 267 – 276

Construction of Metal–Organic Frameworks
FULL PAPER
the program X-Seed[22] as an interface to POV-Ray.[23] CCDC 829646 (1),
829647 (2), 829648 (3), 829649 (4), 829650 (5), 829651 (L·2DMSO),
829652 (L), 829653 (L·2H2O) contain the supplementary crystallographic
data for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif.
14.9220(10), c=19.0290(13) ꢁ, b=105.7710(10)8, V=2836.2(3) ꢁ3, Z=2,
1cald =0.741 gcmꢀ3
,
F
000 =632, MoKa radiation, l=0.71073 ꢁ, T=
150(2) K, 2qmax =54.28, 12321 reflections collected, 8333 unique (Rint
=
0.0293). Final GooF=0.805, R1=0.0349, wR2=0.0728, R indices based
on 6479 reflections with I>2s(I) (refinement on F2), 428 parameters, 604
restraints. Lorenz polarisation and absorption corrections applied, m=
0.413 mmꢀ1. Absolute structure parameter=0.22(2).[26]
All crystals lost solvent quickly and turned opaque upon removal from
the mother liquor. In the case of structures 1–3 the crystal system was de-
termined as cubic with body centring and there are six possible space
groups that all have equivalent reflection conditions. A systematic look
at the solutions produced by SIR-2004 for all of these six space groups fi-
nally yielded the best solution in the chiral space group I432. From EDX
measurements it was determined that different crystals of 3 contained
different ratios of Fe-to-Cu. However, it was not possible to determine
the Fe-to-Cu ratio in the crystal used for the collection of X-ray diffrac-
tion data, and therefore, the occupancy assignment that afforded the best
Uiso and R1 values were assumed to be correct (this reflected a 3:2 ratio
of Cu/Fe). The diffraction data of the crystal of 5 showed signs of
pseudo-merohedral twinning, and could be successfully refined after two
twin laws were included in the refinement. The contributions from disor-
dered solvent molecules (and anions in the case of 1–3) were removed by
the SQUEEZE[24] routine within PLATON,[25] and the outputs from the
SQUEEZE calculations are attached to each CIF file.
Acknowledgements
We thank Benjamin Murray and Tamsin Malkin for use of powder dif-
fractometer; Fiona Meldrum and Alexander Kulak for use of thermal
analysis and sorption facilities; Algy Kazlauciunas for EDX measure-
ments; and the Leverhulme Trust for funding.
[1] a) B. F. Abrahams, B. F. Hoskins, D. M. Michail, R. Robson, Nature
1994, 369, 727–729; b) S. R. Batten, R. Robson, Angew. Chem.
1998, 110, 1558–1595; Angew. Chem. Int. Ed. 1998, 37, 1460–1494;
c) A. J. Blake, N. R. Champness, P. Hubberstey, W. S. Li, M. A.
Withersby, M. Schroder, Coord. Chem. Rev. 1999, 183, 117–138;
d) R. Robson, J. Chem. Soc. Dalton Trans. 2000, 3735–3744; e) B.
Moulton, M. J. Zaworotko, Chem. Rev. 2001, 101, 1629–1658; f) L.
Brammer, Chem. Soc. Rev. 2004, 33, 476–489.
[2] a) S. L. James, Chem. Soc. Rev. 2003, 32, 276–288; b) M. Eddaoudi,
J. Kim, N. Rosi, D. Vodak, J. Wachter, M. OꢄKeefe, O. M. Yaghi,
Science 2002, 295, 469–472; c) H. K. Chae, D. Y. Siberio-Perez, J.
Kim, Y. Go, M. Eddaoudi, A. J. Matzger, M. OꢄKeeffe, O. M. Yaghi,
Nature 2004, 427, 523–527; d) J. L. C. Rowsell, A. R. Millward,
K. S. Park, O. M. Yaghi, J. Am. Chem. Soc. 2004, 126, 5666–5667;
e) D. Bradshaw, J. B. Claridge, E. J. Cussen, T. J. Prior, M. J. Ros-
seinsky, Acc. Chem. Res. 2005, 38, 273–282; f) J. L. C. Rowsell,
O. M. Yaghi, Angew. Chem. 2005, 117, 4748–4758; Angew. Chem.
Int. Ed. 2005, 44, 4670–4679; g) A. R. Millward, O. M. Yaghi, J. Am.
Chem. Soc. 2005, 127, 17998–17999.
Crystal data for L·2DMSO: C26H28N6O4S2, M=552.66, colourless rod,
3
¯
0.30ꢃ0.13ꢃ0.09 mm , triclinic, space group P1 (No. 2), a=7.5178(8), b=
8.6729(9), c=10.6312(11) ꢁ, a=80.574(7), b=79.588(6), g=84.448(6)8,
V=670.93(12) ꢁ3, Z=1, 1cald =1.368 gcmꢀ3, F000 =290, MoKa radiation,
l=0.71073 ꢁ, T=150(2) K, 2qmax =52.98, 10188 reflections collected,
2726 unique (Rint =0.0381). Final GooF=1.042, R1=0.0666, wR2=
0.1466, R indices based on 2191 reflections with I>2s(I) (refinement on
F2), 172 parameters, 0 restraints. Lorenz polarisation and absorption cor-
rections applied, m=0.243 mmꢀ1
.
Crystal data for 1: C132H144Cu5N46O66, M=3748.63, purple octahedron,
0.20ꢃ0.20ꢃ0.20 mm3, cubic, space group I432 (No. 211), a=32.452(2) ꢁ,
V=34176(4) ꢁ3, Z=4, 1cald =0.729 gcmꢀ3, F000 =7724, MoKa radiation,
l=0.71073 ꢁ, T=30(2) K, 2qmax =52.88, 90317 reflections collected, 5860
unique (Rint =0.0504). Final GooF=1.019, R1=0.0503, wR2=0.1358, R
indices based on 4651 reflections with I>2s(I) (refinement on F2), 189
parameters, 2 restraints. Lorenz polarisation and absorption corrections
applied, m=0.358 mmꢀ1. Absolute structure parameter=0.070(18).[26]
[3] a) J. S. Seo, D. Whang, H. Lee, S. I. Jun, J. Oh, Y. J. Jeon, K. Kim,
Nature 2000, 404, 982–986; b) B. Kesanli, W. B. Lin, Coord. Chem.
Rev. 2003, 246, 305–326.
[4] a) C. Janiak, Dalton Trans. 2003, 2781–2804; A. Y. Robin, K. M.
Fromm, Coord. Chem. Rev. 2006, 250, 2127–2157; b) O. Kahn, C. J.
Martinez, Science 1998, 279, 44–48; c) O. Kahn, Acc. Chem. Res.
2000, 33, 647–657.
Crystal data for 2: C132H132N46O60Zn5, M=3649.69, yellow pyramid, 0.27ꢃ
0.20ꢃ0.13 mm3, cubic, space group I432 (No. 211), a=33.0880(12) ꢁ, V=
36225(2) ꢁ3, Z=4, 1cald =0.669 gcmꢀ3, F000 =7504, MoKa radiation, l=
0.71073 ꢁ, T=173(2) K, 2qmax =44.08, 91583 reflections collected, 3727
unique (Rint =0.0517). Final GooF=1.055, R1=0.0525, wR2=0.1435, R
indices based on 3068 reflections with I>2s(I) (refinement on F2), 198
parameters, 5 restraints. Lorenz polarisation and absorption corrections
applied, m=0.373 mmꢀ1. Absolute structure parameter=0.04(2).[26]
[5] R. Robson, Dalton Trans. 2008, 5113–5131.
[6] a) M. Kondo, T. Okubo, A. Asami, S.-i. Noro, T. Yoshitomi, S. Kita-
gawa, T. Ishii, H. Matsuzaka, K. Seki, Angew. Chem. 1999, 111,
190–193; Angew. Chem. Int. Ed. 1999, 38, 140–143; b) H. Chun,
D. N. Dybtsev, H. Kim, K. Kim, Chem. Eur. J. 2005, 11, 3521–3529;
c) C. Gao, S. Liu, L. Xie, Y. Ren, J. Cao, C. Sun, CrystEngComm
2007, 9, 545–547; d) L.-F. Ma, L.-Y. Wang, X.-K. Huo, Y.-Y. Wang,
Y.-T. Fan, J.-G. Wang, S.-H. Chen, Cryst. Growth Des. 2008, 8, 620–
628; e) L. Carlucci, G. Ciani, D. M. Proserpio, A. Sironi, J. Chem.
Soc. Chem. Commun. 1994, 2755–2756; f) L. R. Macgillivray, S. Sub-
ramanian, M. J. Zaworotko, J. Chem. Soc. Chem. Commun. 1994,
1325–1326; g) O. M. Yaghi, G. M. Li, Angew. Chem. 1995, 107, 232–
234; Angew. Chem. Int. Ed. Engl. 1995, 34, 207–209.
Crystal data for 3: C132H108Cu3Fe2N46O48, M=3396.87, grey hexagon,
0.17ꢃ0.14ꢃ0.01 mm3, cubic, space group I432 (No. 211), a=32.637(4),
V=34764(6) ꢁ3, Z=4, 1cald =0.631 gcmꢀ3, F000 =6740, MoKa radiation,
l=0.71073 ꢁ, T=250(2) K, 2qmax =47.88, 55401 reflections collected,
4522 unique (Rint =0.0370). Final GooF=1.003, R1=0.0390, wR2=
0.1102, R indices based on 3739 reflections with I>2s(I) (refinement on
F2), 161 parameters, 0 restraints. Lorenz polarisation and absorption cor-
rections applied, m=0.303 mmꢀ1
.
Absolute structure parameter=
0.039(19).[26]
[7] A search of the CSD (version 5.32, February 2011 update) reveals
that only dicarboxy-2,2’-bipyridine ligands have been used to exploit
the chelating as well as bridging potential of the 2,2’-bipyridine core,
however, none of these structures employs the trischelate moiety.
[8] a) T. Schareina, C. Schick, B. F. Abrahams, R. Kempe, Z. Anorg.
Allg. Chem. 2001, 627, 1711–1713; b) T. Schareina, C. Schick, R.
Kempe, Z. Anorg. Allg. Chem. 2001, 627, 131–133; c) Y.-H. Liu, Y.-
L. Lu, H.-C. Wu, J.-C. Wang, K.-L. Lu, Inorg. Chem. 2002, 41, 2592–
2597; d) E. Tynan, P. Jensen, N. R. Kelly, P. E. Kruger, A. C. Lees, B.
Moubaraki, K. S. Murray, Dalton Trans. 2004, 3440–3447; e) E.
Tynan, P. Jensen, P. E. Kruger, A. C. Lees, Chem. Commun. 2004,
776–777; f) J. Hafizovic, U. Olsbye, K. P. Lillerud, Acta Crystallogr.
Crystal data for 4: C25H23Cl2CoN7O3, M=599.33, orange block, 0.11ꢃ
0.10ꢃ0.09 mm3, monoclinic, space group P21/c (No. 14), a=16.1896(15),
b=16.3056(14), c=17.2037(14) ꢁ, b=113.868(4)8, V=4153.1(6) ꢁ3, Z=
4, 1cald =0.959 gcmꢀ3
,
F
000 =1228, MoKa radiation, l=0.71073 ꢁ, T=
150(2) K, 2qmax =49.58, 39475 reflections collected, 7074 unique (Rint
=
0.0567). Final GooF=1.038, R1=0.0411, wR2=0.1024, R indices based
on 5110 reflections with I>2s(I) (refinement on F2), 383 parameters, 8
restraints. Lorenz polarisation and absorption corrections applied, m=
0.569 mmꢀ1
.
Crystal data for 5: C22H16CdN8O8, M=632.83, colourless block, 0.30ꢃ
0.25ꢃ0.15 mm3, monoclinic, space group P21 (No. 4), a=10.3790(6), b=
Chem. Eur. J. 2012, 18, 267 – 276
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
275

M. J. Hardie and T. Jacobs
Sect. E 2007, 63, m962–m964; g) N. R. Kelly, S. Goetz, S. R. Batten,
P. E. Kruger, CrystEngComm 2008, 10, 68–78; h) C.-Q. Zhang, F.
Fu, D.-S. Li, Y.-X. Ren, X.-Z. Zhao, Synth. React. Inorg. Met.-Org.
Nano-Met. Chem. 2008, 38, 652–656; i) M. Fang, B. Zhao, Y. Zuo, J.
Chen, W. Shi, J. Liang, P. Cheng, Dalton Trans. 2009, 7765–7770;
j) C.-C. Wang, Asian J. Chem. 2009, 21, 4711–4720; k) A. J. Blake,
N. R. Champness, T. L. Easun, D. R. Allan, H. Nowell, M. W.
George, J. Jia, X.-Z. Sun, Nat. Chem. 2010, 2, 688–694; l) J. Z. Gu,
Z. Q. Gao, W. Dou, M. Y. Tan, Chin. J. Struct. Chem. 2010, 29, 519–
524; m) A. Kobayashi, T. Yonemura, M. Kato, Eur. J. Inorg. Chem.
2010, 2465–2470.
[15] a) Y. Wang, T.-a. Okamura, W.-Y. Sun, N. Ueyama, Cryst. Growth
Des. 2008, 8, 802–804; b) R. A. Smaldone, R. S. Forgan, H. Furuka-
wa, J. J. Gassensmith, A. M. Z. Slawin, O. M. Yaghi, J. F. Stoddart,
Angew. Chem. 2010, 122, 8812–8816; Angew. Chem. Int. Ed. 2010,
49, 8630–8634; c) K. S. Jeong, Y. B. Go, S. M. Shin, S. J. Lee, J. Kim,
O. M. Yaghi, N. Jeong, Chem. Sci. 2011, 2, 877–882; d) L. R. Mac-
Gillivray, J. L. Atwood, Nature 1997, 389, 469–472.
[16] a) J. Pauls, S. Chitsaz, B. Neumuller, Z. Anorg. Allg. Chem. 2000,
626, 2028–2034; b) S. Chitsaz, B. Neumuller, Organometallics 2001,
20, 2338–2343; c) A. J. Amoroso, S. S. M. Chung, D. J. E. Spencer,
J. P. Danks, M. W. Glenny, A. J. Blake, P. A. Cooke, C. Wilson, M.
Schroder, Chem. Commun. 2003, 2020–2021.
[17] For examples of heterometallic coordination polymers, see: a) B.
Kilduff, D. Pogozhev, S. A. Baudron, M. W. Hosseini, Inorg. Chem.
2010, 49, 11231–11239; b) C. L. Cahill, D. T. de Lill, M. Frisch, Crys-
tEngComm 2007, 9, 15–26; c) S. R. Halper, S. M. Cohen, Inorg.
Chem. 2005, 44, 486–488; d) D. W. Ryu, W. R. Lee, J. W. Lee, J. H.
Yoon, H. C. Kim, E. K. Koh, C. S. Hong, Chem. Commun. 2010, 46,
8779–8781; e) D. Sun, D.-F. Wang, X.-G. Han, N. Zhang, R.-B.
Huang, L.-S. Zheng, Chem. Commun. 2011, 47, 746–748.
[18] a) M.-D. Serb, M. Speldrich, H. Lueken, U. Englert, Z. Anorg. Allg.
Chem. 2011, 637, 536–542; b) B. Jee, K. Eisinger, F. Gul-E-Noor, M.
Bertmer, M. Hartmann, D. Himsl, A. Poeppl, J. Phys. Chem. C
2010, 114, 16630–16639; c) M. Lusi, J. L. Atwood, L. R. MacGilliv-
ray, L. J. Barbour, CrystEngComm 2011, 13, 4311–4313.
[19] M. Schwalbe, B. Schafer, H. Gorls, S. Rau, S. Tschierlei, M. Schmitt,
J. Popp, G. Vaughan, W. Henry, J. G. Vos, Eur. J. Inorg. Chem. 2008,
3310–3319.
[9] G. R. Newkome, A. K. Patri, E. Holder, U. S. Schubert, Eur. J. Org.
Chem. 2004, 235–254.
[10] For examples of spontaneous resolution, see: a) B. Gil-Hernꢅndez,
H. A. Hoeppe, J. K. Vieth, J. Sanchiz, C. Janiak, Chem. Commun.
2010, 46, 8270–8272; b) H. D. Flack, Acta Crystallogr. Sect. A 2009,
65, 371–389; c) C. Janiak, A.-C. Chamayou, A. K. M. R. Uddin, M.
Uddin, K. S. Hagen, M. Enamullah, Dalton Trans. 2009, 3698–3709;
d) M. Enamullah, A. Sharmin, M. Hasegawa, T. Hoshi, A. C. Cha-
mayou, C. Janiak, Eur. J. Inorg. Chem. 2006, 2146–2154.
[11] a) Y. Inokuma, T. Arai, M. Fujita, Nat. Chem. 2010, 2, 780–783;
b) B. F. Abrahams, S. R. Batten, H. Hamit, B. F. Hoskins, R.
Robson, Angew. Chem. 1996, 108, 1794–1796; Angew. Chem. Int.
Ed. Engl. 1996, 35, 1690–1692; c) H. M. El-Kaderi, J. R. Hunt, J. L.
Mendoza-Cortes, A. P. Cote, R. E. Taylor, M. OꢄKeeffe, O. M.
Yaghi, Science 2007, 316, 268–272; d) S. S. Y. Chui, S. M. F. Lo,
J. P. H. Charmant, A. G. Orpen, I. D. Williams, Science 1999, 283,
1148–1150; e) F. Nouar, J. F. Eubank, T. Bousquet, L. Wojtas, M. J.
Zaworotko, M. Eddaoudi, J. Am. Chem. Soc. 2008, 130, 1833–1835;
f) J. J. Perry IV, J. A. Perman, M. J. Zaworotko, Chem. Soc. Rev.
2009, 38, 1400–1417.
[20] G. M. Sheldrick, Acta Crystallogr. Sect. A 2008, 64, 112–122.
[21] M. C. Burla, R. Caliandro, M. Camalli, B. Carrozzini, G. L. Cascara-
no, L. De Caro, C. Giacovazzo, G. Polidori, R. Spagna, J. Appl.
Crystallogr. 2005, 38, 381–388.
[22] L. J. Barbour, J. Supramol. Chem. 2001, 1, 189–191.
[23] Persistence of Vision Raytracer, Version 3.6., Williamstown, Aus-
tralia, 2004.
[12] a) V. A. Blatov, A. P. Shevchenko, V. N. Serezhkin, J. Appl. Crystal-
logr. 2000, 33, 1193; b) M. OꢄKeeffe, M. Eddaoudi, H. L. Li, T. Rein-
eke, O. M. Yaghi, J. Solid State Chem. 2000, 152, 3–20.
[13] a) N. G. Naumov, A. V. Virovets, M. N. Sokolov, S. B. Artemkina,
V. E. Fedorov, Angew. Chem. 1998, 110, 2043–2045; Angew. Chem.
Int. Ed. 1998, 37, 1943–1945; b) N. G. Naumov, A. V. Virovets, S. B.
Artemkina, D. Y. Naumov, J. A. K. Howard, V. E. Fedorov, J. Solid
State Chem. 2004, 177, 1896–1904; c) Y. Liu, J. F. Eubank, A. J.
Cairns, J. Eckert, V. C. Kravtsov, R. Luebke, M. Eddaoudi, Angew.
Chem. 2007, 119, 3342–3347; Angew. Chem. Int. Ed. 2007, 46, 3278–
3283.
[24] P. Van der Sluis, A. L. Spek, Acta Crystallogr. Sect. A 1990, 46, 194–
201.
[25] A. L. Spek, Acta Crystallogr. Sect. D 2009, 65, 148–155.
[26] a) H. D. Flack, Acta Crystallogr. Sect. A 1983, 39, 876–881; b) H. D.
Flack, M. Sadki, A. L. Thompson, D. J. Watkin, Acta Crystallogr.
Sect. A 2011, 67, 21–34; c) H. D. Flack, G. Bernardinelli, Chirality
2008, 20, 681–690; d) H. D. Flack, G. Bernardinelli, Acta Crystal-
logr. Sect. A 1999, 55, 908–915.
[14] a) B. Wu, J. Yang, X. Huang, S. Li, C. Jia, X.-J. Yang, N. Tang, C.
Janiak, Dalton Trans. 2011, 40, 5687–5696; b) B. Wu, X. J. Yang, C.
Janiak, P. G. Lassahn, Chem. Commun. 2003, 902–903.
Received: June 28, 2011
Published online: December 2, 2011
276
www.chemeurj.org
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2012, 18, 267 – 276