Structures and H2 adsorption properties of porous scandium metal-organic frameworks

Article abstract of DOI:10.1002/chem.201000926

Two new three-dimensional Sc^III metal-organic frameworks {[Sc₃O(L¹)₃(H₂O)₃] ·Cl_0.5(OH)_0.5(DMF)₄(H₂O) ₃}_∞ (1) (H₂L¹=1,4-benzene- dicarboxylic acid) and {[Sc₃O(L²)₂(H ₂O)₃](OH)(H₂O)₅(DMF)} _∞ (2) (H₃L²=1,3,5-tris(4-carboxyphenyl) benzene) have been synthesised and characterised. The structures of both 1 and 2 incorporate the trinuclear trigonal planar [Sc₃(O)(O ₂CR)₆] building block featuring three Sc^III centres joined by a central μ₃-O^2- donor. Each Sc ^III centre is further bound by four oxygen donors from four different bridging carboxylate anions, and a molecule of water located trans to the μ₃-O^2- donor completes the six coordination at the metal centre. Frameworks 1 and 2 show high thermal stability with retention of crystallinity up to 350 °C. The desolvated materials 1 a and 2 a, in which the solvent has been removed from the pores but with water or hydroxide remaining coordinated to Sc^III, show BET surface areas based upon N₂ uptake of 634 and 1233 M² g^-1, respectively, and pore volumes calculated from the maximum N₂ adsorption of 0.25 Cm³ g^-1 and 0.62 Cm³ g^-1, respectively. At 20 Bar and 78 K, the H₂ isotherms for desolvated 1 a and 2 a confirm 2.48 and 1.99 Wt % total H₂ uptake, respectively. The isosteric heats of adsorption were estimated to be 5.25 and 2.59 KJ mol ^-1 at zero surface coverage for 1 a and 2 a, respectively. Treatment of 2 with acetone followed by thermal desolvation in vacuo generated free metal coordination sites in a new material 2 b. Framework 2 b shows an enhanced BET surface area of 1511 M² g^-1 and a pore volume of 0.76 Cm³ g^-1, with improved H₂ uptake capacity and a higher heat of H₂ adsorption. At 20 Bar, H₂ capacity increases from 1.99 Wt % in 2 a to 2.64 Wt % for 2 b, and the H₂ adsorption enthalpy rises markedly from 2.59 to 6.90 KJ mol^-1. It's Sc^IIIandalous: {[Sc₃O(L¹)₃(H ₂O)₃]·Cl_0.5OH_0.5(DMF) ₄(H₂O)₃}_∞ (1) (H ₂L¹=1,4-benzenedicarboxylic acid) and {[Sc ₃O(L²)₂(H₂O)₃]OH(H ₂O)₅(DMF)}_∞ (2) (H₃L ²=1,3,5-tris(4-carboxyphenyl)benzene) incorporate the trinuclear trigonal planar [Sc₃(O)(O₂CR)₆] building block. After appropriate thermal treatment on the acetone-exchanged sample 2, the generation of free metal coordination sites has been achieved to give an increase in the BET surface area in 2 b. Copyright

Full text of DOI:10.1002/chem.201000926

FULL PAPER
DOI: 10.1002/chem.201000926
Structures and H Adsorption Properties of Porous Scandium
2
Metal–Organic Frameworks
[
a]
[a]
[a]
[a]
[b]
Ilich A. Ibarra, Xiang Lin, Sihai Yang, Alexander J. Blake, Gavin S. Walker,
[
c]
[c]
[a]
[a]
Sarah A. Barnett, David R. Allan, Neil R. Champness,* Peter Hubberstey, and
[
a]
Martin Schrçder*
Abstract: Two new three-dimensional
show high thermal stability with reten-
tion of crystallinity up to 3508C. The
desolvated materials 1a and 2a, in
which the solvent has been removed
from the pores but with water or hy-
firm 2.48 and 1.99 wt% total H2
uptake, respectively. The isosteric heats
of adsorption were estimated to be
III
Sc
metal–organic
frameworks
(DMF) -
1
{[Sc O(L )
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(H O) ]·Cl (OH)
A
H
U
T
E
N
N
3
3
2
3
0.5
0.5
4
1
ꢀ1
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(H O) } (1) (H L =1,4-benzene-dicar-
5.25 and 2.59 kJmol at zero surface
2
3
1
2
2
boxylic
acid)
and
{[Sc O(L ) -
coverage for 1a and 2a, respectively.
Treatment of 2 with acetone followed
by thermal desolvation in vacuo gener-
ated free metal coordination sites in a
new material 2b. Framework 2b shows
an enhanced BET surface area of
3
2
III
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(H O) ](OH)
H L =1,3,5-tris(4-carboxyphenyl)ben-
3
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(H O)
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(DMF)}
(2)
droxide remaining coordinated to Sc ,
2
3
2
5
1
2
(
show BET surface areas based upon N
uptake of 634 and 1233 m g , respec-
tively, and pore volumes calculated
2
2
ꢀ1
zene) have been synthesised and char-
acterised. The structures of both 1 and
2
incorporate the trinuclear trigonal
from the maximum N adsorption of
2
3
ꢀ1
3
ꢀ1
2
ꢀ1
ꢀ1
planar [Sc (O)(O CR) ] building block
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
0.25 cm g
and 0.62 cm g , respec-
1511 m g
and a pore volume of
3
2
III
6
3
featuring three Sc centres joined by a
central m -O donor. Each Sc centre
tively. At 20 bar and 78 K, the H iso-
0.76 cm g , with improved H uptake
2
2
2ꢀ
III
therms for desolvated 1a and 2a con-
capacity and a higher heat of H ad-
3
2
is further bound by four oxygen donors
from four different bridging carboxyl-
ate anions, and a molecule of water lo-
sorption. At 20 bar, H2 capacity in-
creases from 1.99 wt% in 2a to
Keywords: carboxylate ligands
coordination polymers · free metal
·
2.64 wt% for 2b, and the H adsorp-
2
2
ꢀ
cated trans to the m3-O
donor
tion enthalpy rises markedly from 2.59
coordination sites
scandium
· hydrogen ·
ꢀ
1
completes the six coordination at the
metal centre. Frameworks 1 and 2
to 6.90 kJmol .
Introduction
The development of coordination polymers in materials sci-
ence, crystal engineering and supramolecular chemistry is a
[1]
very timely area of research. The design and synthesis of
such networks is driven by diverse potential applications in
gas storage, catalysis, electrical conductivity, lumines-
[
a] I. A. Ibarra, Dr. X. Lin, S. Yang, Prof. Dr. A. J. Blake,
Prof. Dr. N. R. Champness, Dr. P. Hubberstey,
Prof. Dr. M. Schrçder
School of Chemistry, University of Nottingham
Nottingham NG7 2RD (UK)
Fax : (+44)115-951-3563
[2]
[3]
[4]
[5]
[6]
[7]
cence, magnetism and optics. Hydrogen has enormous
[8]
potential as a sustainable, clean and efficient fuel. Thus,
many industrial economies are investing in the hydrogen
economy as a major contribution to sustainability and for
use in the clean technologies of the future. There is, there-
fore, an enormous current interest in developing new metal–
[9]
E-mail: m.schroder@nottingham.ac.uk
[
b] Prof. Dr. G. S. Walker
School of Mechanical Materials & Manufacturing Engineering
University of Nottingham, Nottingham NG7 2RD (UK)
organic frameworks that show permanent porosity as H
2
[
c] Dr. S. A. Barnett, Dr. D. R. Allan
Diamond Light Source, Harwell Science and Innovation Campus
Didcot, Oxfordshire, OX11 0DE (UK)
[10]
storage materials.
A very important parameter used to
characterise this kind of material is the isosteric heat of ad-
[11]
sorption, which describes the H binding energy in porous
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201000926.
2
materials. The typical values of heat adsorption for a metal–
Chem. Eur. J. 2010, 16, 13671 – 13679
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
13671

III
organic frameworks (at 78 K) are between
5
and
block. Our approach to the synthesis of two Sc polymers
(1 and 2) is based on templating the trinuclear [Sc (m -O)-
ꢀ
1 [12–15]
8
kJmol ,
but higher values of isosteric heat adsorption
ACHTUNGTRENNUNG
3
3
ꢀ
1
[16]
(
15–20 kJmol ) are required for a H storage system that
ACHTUNGTNERNUN(G O CR) ] building blocks, which have the potential to give
2 6
2
functions at room temperature and within a pressure range
products of high thermal stability. We have also investigated
the importance and relevance of free metal coordination
sites generated by solvent exchange followed by thermal
treatment.
of 1.5–20 bar. In order to enhance the H binding energy in
2
these materials, strategies such as the formation of very
[14,15,17]
narrow pores
(in which overlapping potentials from
two or more pore walls increases the binding energy be-
tween the H and the framework), framework catenation/in-
2
[18]
terpenetration and doping of frameworks with light elec-
Results and Discussion
tron-donating non-transition-metal centres to increase H
2
[19]
uptake have been undertaken. In particular, access to ex-
Synthesis and Structure
posed metal sites can increase the affinity of H through
direct coordination to metal centres.
Solvothermal reaction of ScCl ·xH O with benzene-1,4-di-
2
3
2
[12,20,21]
1
carboxylic acid (H L : Scheme 1) in a slightly acidified mix-
2
Most of the porous coordination framework polymers re-
ported thus far have been based on divalent cations,
ture of N,N’-dimethylformamide, 1,4-dioxane and water af-
1
forded {[Sc O(L )
ScCl ·xH O and 1,3,5-tris(4-carboxyphenyl)benzene (H L :
3 2 3
A
H
U
G
R
N
U
G
A
H
U
G
R
N
U
G
A
H
U
G
R
N
U
(H O) } (1).
3
3
2
3
0.5
0.5
4
2
3
1
II
II
2
commonly those of late-transition-metals such as Zn , Cu
II
and Ni . In contrast, framework polymers derived from tri-
valent cations are less well known and are most commonly
Scheme 1) in acidified mixture of N,N’-dimethylformamide,
tetrahydrofuran, dichloromethane and water under solvo-
III [22,23]
III [24,25]
III[26,27]
III [28]
2
based upon Cr ,
Sc ,
V
and Fe . There is
thermal conditions produced {[Sc O(L )
A
H
U
G
R
N
N
(H O) ](OH)-
3
2
2
3
III
a growing interest in the use of Sc centres as components
of porous frameworks because scandium is lighter than late
divalent transitions metals, requires a higher ratio of ligands
that contain only low-atomic-weight elements, and can also
ACTHUNGERTNNUN(G H O)5 AHCTUNGTRENUNN(G DMF)} (2).
2 1
[29]
favour high coordination numbers. Relatively few exam-
III
ples of Sc coordination polymers have been reported in
[
24,25,30–34]
the literature,
but notable examples include
1
1
[24,30]
[
Sc (L ) ] (H L =benzene-1,4-dicarboxylic acid),
which
2
3
2
exhibits ScO6 octahedra linked to six other metal nodes
through bridging carboxylates. This material has a pore
3
ꢀ1
volume of 0.29 cm g and a H uptake capacity of 1.4 wt%
2
[24,30]
at 0.66 bar.
Of direct relevance to the work reported
herein, Dietzel and co-workers have synthesised the first
1
2
Scheme 1. H
2 3
L (1,4-benzene-dicarboxylic acid) and H L (1,3,5-tris(4-car-
[33]
boxyphenyl)benzene).
III
example of
a
m3-oxo bridged Sc
framework [Sc O-
3
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(H O) (L) X]
ACHTUNGTRENNUNG( DEF) (X=Cl, NO ) (H L=benzene-2,5-di-
2
3
3
4
3
2
hydroxy-1,4-dicarboxylic acid), which was found to decom-
A single-crystal X-ray structural determination confirms
pose at around 1408C upon removal of the solvent mole-
cules and showed no permanent porosity. Other related Sc
that 1 crystallises in the hexagonal space group P6 /mmc,
and has a structure based around the trinuclear building
block [Sc (O) ACHUTNRTGENNUNG( O CR) ] (Figure 1a and c), two of which are
3 2 6
3
III
[
32]
frameworks based upon methylphosphonates,
succi-
[25,31]
nates,
1,5- and 2,6-naphthalenedisulfonate frame-
works have also been reported and have been shown to
be active catalysts for acetylation and oxidation reac-
present in each unit cell. In each [Sc (O)
three Sc centres are joined by a central m -oxygen atom
A
H
U
G
R
N
N
(O CR) ] unit,
3
2
6
[35]
III
3
[ScꢀO 2.0254(8) ꢁ] and the unit adopts a trigonal planar ge-
[25,31]
tions
as well as selective bifunctional heterogeneous cat-
ometry and occupies a site of crystallographic D symmetry.
3
h
alysts in the epoxidation of linalool and the oxidation of sul-
Each pair of centres is bridged by two carboxylate groups
such that each metal centre is coordinated by four oxygen
[35]
phides.
Binuclear [M
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(O CR) ] and tetranuclear [M O
A
H
N
T
E
N
N
(O CR) ]
donors from different anions, and a molecule of water is lo-
2
2
4
4
2
6
III
clusters have been used as nodes in framework construc-
cated trans to the m -oxygen atom completing the Sc
3
[36]
tion. In comparison, fewer examples of coordination poly-
mers based on trinuclear clusters of the type [M3(m -O)-
(O CR) ] have been reported, although a range of metal
coordination sphere. Although this coordination is approxi-
mately octahedral, the metal occupies a site of lower crystal-
AHCTUNGTRENNUNG
3
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
lographic symmetry (C ). The main characteristic of the
2
6
2v
centres have been incorporated to give m -oxo bridged tri-
[Sc (O) ACHTUNGTRNENUG( O CR) ] building block is the junction of the three
3 2 6
3
III [26]
III [23,37]
III [28,38,39]
III [14,40]
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
nuclear clusters of V ,
Cr ,
Fe ,
In ,
octahedra by sharing a m -oxygen atom (Figure 1b). Each
3
III [41]
III[42]
II[39]
Al , Ga
and Ni
. We were interested in developing
trinuclear cluster is connected to six neighbouring clusters
through six benzene-1,4-dicarboxylates, and each trinuclear
III
the framework chemistry of Sc in parallel with our previ-
ous studies on the use of late-transition-metal centres as
nodes in coordination polymer construction, and targeted
cluster [Sc (O) CAHTUNGTRNEUN(G O CR) ] can be viewed as a node linked to
2 6
3
[43]
six nearby cluster nodes. Thus, the framework exhibits a
9
6
the rare m -oxo [Sc O] fragment as a potential building
three-dimensional network structure of 4 6 topology incor-
3
3
13672
www.chemeurj.org
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 13671 – 13679

Porous Sc Metal–Organic Frameworks
FULL PAPER
III
(
Figure 1a and d). Three Sc centres are joined by a central
m -oxygen atom, with ScꢀO bond lengths in the range
3
1
.991(3)–2.038(5) ꢁ, and they adopt a trigonal planar geom-
III
etry on a site of crystallographic C symmetry. Each Sc
s
centre is octahedrally bound to six oxygen atoms from four
different carboxylate groups, and a molecule of water is lo-
cated trans to the m -oxygen atom. Each trinuclear building
3
block is connected to twelve neighbouring building blocks
2
3ꢀ
through six ligands [L ] , and the pore diameter of this
framework calculated from the crystal structure is approxi-
mately 23 ꢁ (Figure 3a and b). The precise locations of
Figure 3. a) View of the three-dimensional framework 2 along the c axis,
which shows the channels of the structure; b) space-filling view along the
crystallographic c axis for 2 (Sc=blue, O=red and C=black and H=
grey).
Figure 1. a) Six-coordination of three scandium centres in approximately
octahedral geometry; b) polyhedral representation of the three octahedra
sharing a m -oxygen atom; c) trinuclear building block of 1 showing the
3
2ꢀ
1
ligand ([L ] ) coordinated to the three scandium centres; d) trinuclear
2
3ꢀ
building block of 2, which shows the ligand ([L ] ) coordinated to the
three scandium centres.
ꢀ
OH within the structure could not be determined by
ꢀ
single-crystal X-ray diffraction, but the presence of OH
porating pores of approximately 7.6 ꢁ diameter (Figure 2a)
as calculated from the crystal structure. This value is in good
agreement with the value of 8.0 ꢁ estimated from the N2
isotherm (see below). The channels are connected by
narrow windows of approximately 3.5 ꢁ diameter
was confirmed by elemental analysis and XPS. Although the
definition of protonation states of bound and in-pore H O,
2
ꢀ
2ꢀ
OH and O moieties can be problematic in this type of
system (see below), bond valence sum analysis confirms that
the trinuclear cluster in 1 and 2 comprises of Sc centres
III
ꢀ
ꢀ
2ꢀ
(
Figure 2b). The precise locations of Cl and OH within
with a central m -O donor (see the Supplementary Infor-
3
the structure could not be determined by single-crystal X-
ray diffraction, but the presence of Cl was confirmed by X-
ray photoelectron spectroscopy (XPS).
mation), and the terminal ScꢀO bond lengths, 2.102(4) ꢁ
ꢀ
for 1, and 2.137(7) and 2.155(5) ꢁ for 2, are consistent with
[33,44]
coordinated H O.
2
Thermogravimetric analysis of 1 and 2 under N shows
2
one main, continuous, weight loss of 21% (1) or 16% (2)
over temperature ranges of 25–2508C and 25–3408C, respec-
tively. Whereas compound 1 starts to decompose at 4908C, 2
reaches a plateau above 3408C with the structure decompos-
ing at 5208C, a very high decomposition temperature for a
metal–organic hybrid material. In situ variable-temperature
powder X-ray diffraction (PXRD) measurements on sam-
ples of 1 and 2 held under vacuum confirmed the retention
of crystallinity and overall structure of the frameworks up to
3508C, with a good fit observed between the experimental
PXRD data and that calculated from the single-crystal data.
In order to establish the fate of the water molecules
within these materials, FTIR spectra were recorded over a
range of temperatures under a flow of He gas. The FTIR
spectrum of 1 at 258C (Figure 4a) shows a broad absorption
Figure 2. a) View of the three-dimensional framework 1 along the c axis,
which shows the channels of the structure; b) view of 1 along the b axis,
which shows the windows that connect the framework channels (Sc=
blue, O=red and C black; H atoms are omitted for clarity).
The structure of 2, solved by single-crystal X-ray methods,
ꢀ
1
¯
crystallises in the hexagonal space group P62c and, as for 1,
is based around the trinuclear cluster node [Sc (O)(O CR) ]
band at 3490 cm , confirming the presence of water at
room temperature. A slight decrease in the intensity of this
AHCTUNGTRENNUNG
3
2
6
Chem. Eur. J. 2010, 16, 13671 – 13679
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
13673

M. Schrçder, N. R. Champness et al.
free water was observed, indicating that only uncoordinated
molecules are removed from the framework on heating.
The free solvent molecules in the pores in 1 can be readily
exchanged for other organic solvents such as acetone and
this promotes accessibility to solvent-free frameworks after
appropriate thermal treatment. The FTIR spectrum of the
acetone-exchanged sample 1 under a He flow clearly
showed the two relevant features: the broad absorption
band assigned to uncoordinated water and the sharp peak
assigned to coordinated water/hydroxide. At 258C the FTIR
spectrum of the acetone-exchanged sample 1 (Figure 5)
Figure 5. FTIR spectra of the acetone-exchanged sample 1 at various
temperatures under He flow, which shows the peak attributed to
coordinated water/hydroxide.
Figure 4. a) FTIR spectra of 1 at various temperatures (under He flow);
b) FTIR difference spectra of 1, which shows the peak attributed to
coordinated water/hydroxide.
ꢀ
1
showed a broad absorption band at 3490 cm , confirming
the presence of uncoordinated water in the framework. A
significant decrease in the intensity of this band is observed
on increasing the temperature from 25 to 508C. At 1008C
the band is lost from the spectra, indicating the removal of
free water from the framework but with retention of the
band is observed on raising the temperature from 25 to
508C under a flow of He gas, and a significant reduction in
ꢀ
1
the intensity is observed on heating to 1008C. At 3508C the
band has almost entirely disappeared, indicating the loss of
nearly all of the water from the framework. We were unable
characteristic sharp peak at 3680 cm that is assigned to
metal-coordinated water or hydroxide (Figure 5). Between
room temperature and 3508C this peak is retained in the
spectra, suggesting that the coordinated water is not re-
moved from the framework under these conditions and re-
ꢀ
1
to distinguish the sharp peak in the 3400–3700 cm region,
characteristic of coordinated water/hydroxide from the in-
tense broad band produced by uncoordinated water by
means of conventional FTIR spectroscopy (Figure 4a).
Therefore, difference spectroscopy was used to extract infor-
mation from changes in intensities of overlapping bands.
Thus, plotting differences between spectra at two tempera-
tures (Figure 4b) allows differentiation of the two contribu-
III
mains bound to Sc .
FTIR spectra of 2 at different temperatures were mea-
sured under a He flow. At 258C the broad absorption band
at 3410 cm that is characteristic of uncoordinated water
was observed, which was accompanied by a peak at
3680 cm (Figure 6). A continuous decrease in the intensity
of the band at 3410 cm is observed on raising the tempera-
ture from 25 to 2008C, suggesting the loss of free water
from the framework; meanwhile the intensity of the sharp
peak at 3680 cm remains unchanged. Upon increasing the
temperature from 200 to 2508C, the band at 3410 cm is
ꢀ
1
ꢀ
1
ꢀ
1
ꢀ1
tions. A sharp peak at 3680 cm attributed to coordinated
water or hydroxide is discernible in the difference spectrum.
ꢀ
1
Definitive assignment of the sharp peak at 3680 cm to
[
33,44,45]
ꢀ1
either bound water or hydroxide was problematic
in
ꢀ
1
ꢀ1
this case owing to overlapping bands in the 1600 cm
region from strong carboxylate stretches masking any dis-
tinctive H-O-H bending mode. At temperatures below
completely lost from the spectra, indicating removal of all of
the uncoordinated water from the framework pores. Inter-
estingly, and in contrast to compound 1, the sharp peak at
ꢀ
1
2508C, the broad band at 3490 cm that is characteristic of
13674
www.chemeurj.org
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 13671 – 13679

Porous Sc Metal–Organic Frameworks
FULL PAPER
ꢀ
10
1
708C and 10 bar for 12 h gave the fully desolvated
materials 1a and 2a that retained coordinated water with
optimised porosity. Acetone exchange of a sample 2 for 96 h
ꢀ
10
followed by degassing at 2508C and 10 bar for 12 h af-
forded the fully desolvated material 2b with coordinated
water/hydoxide removed. Heating of 1 and 2 in vacuo with-
out solvent exchange afforded materials of lower apparent
porosity that had lower gas-uptake capacity, possibly due to
framework degradation.
Gas adsorption analysis
Both N adsorption analyses for 1a and 2a show typical
2
Type I isotherm characteristics of microporous materials,
which verifies the retention of the microporosity on removal
of free solvents within the framework. The observed hyster-
Figure 6. FTIR spectra of 2 at various temperatures under He flow show-
ing the peak attributed to coordinated water/hydroxide.
AHCTUNGTRENNUGNe sis loop in the isotherm for 1a (Figure 8a) with a step in
the profile for N adsorption–desorption is evidence for a ki-
2
netic trap consistent with the charged nature of the micro-
porous framework that is modulated by the presence of
ꢀ
1
[46]
3
680 cm is also lost from the spectra. On heating the
anions in the pores.
The overall shape of the isotherm
sample from 250 up to 3508C there is no further significant
change in the spectra. Similar changes in the IR spectrum of
the acetone-exchanged sample 2 (Figure 7) are observed
plot for 2a (Figure 8b) suggests a two-step adsorption al-
though the N adsorption analysis shows a Type I isotherm.
2
Non-local density functional theory (NLDFT) analysis of
the isotherm data for 2a (Figure 8c) confirms a pore diame-
ter of 23.3 ꢁ, consistent with the value determined from the
crystal structure of 2. The Brunauer–Emmett–Teller (BET)
surface areas and pore volumes calculated from the maxi-
mum N adsorption for 1a and 2a were estimated to be
2
ꢀ1
2
3
ꢀ1
2
ꢀ1
3
ꢀ1
6
34 m g /0.25 cm g and 1233 m g /0.62 cm g , respec-
tively.
Gravimetric H adsorption isotherms were measured for
2
these materials from 0–20 bar at 78 K and 88 K (Table 1).
All data were strictly corrected for the buoyancy of the
system, samples and absorbates. All H sorption isotherms
2
showed good reversibility characteristic of microporous
materials (Figure 8d, e and f). The values for the total H2
uptake for the samples 1a and 2a are 2.48 and 1.99 wt%, re-
spectively, at 20 bar. Significantly, solvent exchange repre-
sents a fundamental treatment step to enable formation of a
fully solvent-free material. Materials 1 and 2 that were pre-
Figure 7. FTIR spectra of the acetone-exchanged sample 2 at various
temperatures under He flow showing the peak attributed to coordinated
water/hydroxide.
pared without acetone exchange but with degassing at
ꢀ10
1
708C and 10 bar for 36 h gave lower overall total H up-
2
takes of 1.62 and 1.33 wt%, respectively, at 20 bar, confirm-
ing the importance of acetone-exchange treatment prior to
any gas-adsorption experiment.
with removal of uncoordinated water by 1508C and
coordinated water by 2508C. Thus, the FTIR results suggest
that in the acetone-exchanged sample 1 it is possible to
remove the uncoordinated water at 1008C and the
The H adsorption enthalpy was determined by recording
2
isotherms at 78 and 88 K from 0–20 bar, and the data were
[47]
analysed by using a virial-type equation.
The isosteric
III
coordinated water/hydroxide remains bound to Sc even at
heats of adsorption were estimated to be 5.25 and
ꢀ
1
3508C. However, in the acetone-exchanged sample 2 the un-
2.59 kJmol at zero surface coverage for 1a and 2a, respec-
tively, (Figure 9). These values decrease with increasing H2
loading as expected. These are relatively low values relative
to the systems that incorporate free metal coordination sites
coordinated water is removed at 1508C and the coordinated
water/hydroxide can be removed at 2508C.
A range of experiments was conducted on the desolvation
of 1 and 2 under a range of conditions (various desolvation
and activation temperatures and times) to optimise the po-
rosity of the resultant materials 1a, 2a and 2b. Treatment of
in which interaction between H and metal centres can be
2
[11,21]
maximised.
For sample 2a the isosteric heat of adsorp-
tion is even lower than 1a owing to the large pore size of 2a
1
and 2 with acetone for 96 h followed by degassing at
(ꢁ23 ꢁ); thus, the overall interaction between H and the
2
Chem. Eur. J. 2010, 16, 13671 – 13679
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
13675

M. Schrçder, N. R. Champness et al.
Figure 8. a) N
c) pore-size distribution for compounds 2a and 2b; d) H
0 bar at 78 and 88 K for 2a; f) H adsorption isotherms up to 20 bar at 78 and 88 K for 2b.
2
adsorption isotherm and pore-size distribution for compound 1a; b) N
2
adsorption isotherms for compounds 2a and 2b, respectively;
2
adsorption isotherms up to 20 bar at 78 and 88 K for 1a; e) H
2
adsorption isotherms up to
2
2
III
Table 1. Gas-adsorption data for 1a, 2a and 2b.
high binding energy between H and a vacant site on Sc
2
would be expected within a porous hybrid solid. Taking the
reverse argument, the relatively low value of the isosteric
1
a
2a
2b
free metal coordination sites
pore diameter [ꢁ]
no
8.0
no
yes
23.3
0.62
1233
0.91
1.99
2.59
25.8
0.76
1511
1.01
2.64
6.90
heat for H adsorption in 1a is consistent with the absence
2
3
ꢀ1
pore volume [cm g
BET surface area [m g
]
0.25
634
0.94
2.44
5.25
of free metal coordination sites supported by in situ infrared
spectroscopy measurements, which confirmed the retention
of the coordinated water/hydroxide at the metal site when
the sample is heated up to 3508C.
2
ꢀ1
]
H
H
2
at 78 K and 1 bar [wt%]
at 78 K and 20 bar [wt%]
2
ꢀ
1
Heat of adsorption [kJmol
]
The shape of the isotherm for 2b (Figure 8b) shows a
two-step adsorption although, like the N isotherm for 2a,
2
pore are concluded to be weaker in 2a. Sun et al. have
shown by using ab initio calculations based on DFT that a
the N adsorption analysis shows a Type I isotherm. NLDFT
analysis for 2b shows a pore diameter of 25.8 ꢁ. The BET
2
[48]
13676
www.chemeurj.org
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 13671 – 13679

Porous Sc Metal–Organic Frameworks
FULL PAPER
Experimental Section
2
Synthesis of H
carbonylphenylboronic acid (2.22 g, 11.4 mmol) and
3.8 mmol) were mixed in 1,4-dioxane (80 mL) and the mixture was de-
gassed under argon for 10 min. [Pd(PPh ] (0.03 g, 0.031 mmol) was
3
L : 1,3,5-Tribromobenzene (1.00 g, 3.1 mmol), 4-ethoxy-
K
3
PO (5.06 g,
4
2
A
H
U
G
R
N
U
G
3 4
)
added to the reaction mixture with stirring and the mixture was heated
to 858C for 4 days under argon. The solution was evaporated to dryness
and the residue was extracted with chloroform. The final product H L
3
was obtained by hydrolysing the crude product with 2m aqueous NaOH,
1
followed by acidification with concentrated HCl (1.18 g, 85%). H NMR
(
DMSO, 300.13 MHz, 298 K): d=8.05 (6H, d; Ar-H), 7.78 (6H, d; Ar-
1
3
H), 7.57 ppm(3H, s; Ar-H); C NMR (DMSO, 300.13 MHz, 298 K): d=
1
1
3
69.1, 140.9, 136.7, 129.4, 127.7, 125.1 ppm; C NMR changed to 1 d.p.,
ꢀ
+
MS (ESI ): m/z: 437.1037 [MꢀH] ; elemental analysis calcd (%) for
27 18 6
C H O
: C 73.97; H 4.14; found: C 74.06; H 4.56.
2
Figure 9. Variation of adsorption enthalpy at low loading of H for 1a
Synthesis of 1: Scandium trichloride hydrate (0.065 g, 0.429 mmol) and
benzene-1,4-dicarboxylic acid (0.020 g, 0.120 mmol) were mixed in N,N’-
dimethylformamide (7.50 mL), 1,4-dioxane (3.75 mL), water (3.75 mL)
and hydrochloric acid (36.5%, 2 drops) and sealed in a pressure tube.
The tube was heated to 808C in an oil bath and then maintained at this
temperature for 3 days. Finally the tube was cooled to room temperature
over a period of 12 h. The colourless crystalline product was separated by
filtration, washed with DMF (5.00 mL) and dried briefly in air (60%
(
red), 2a (black) and 2b (blue).
surface area and pore volume for 2b were estimated to be
2
ꢀ1
3
ꢀ1
1
511 m g and 0.76 cm g , respectively. Gravimetric H
2
adsorption data were recorded on 2b (Figure 8 f) over the
range 0–20 bar at 78 K to give a total H2 uptake of
yield based on the ligand). Elemental analytical data corresponds to
[
47]
2
6
.64 wt% at 20 bar with
a
heat of adsorption
of
1
{
[Sc
3
O(L )
3
A
H
U
G
R
N
U
G
2
O)
3
].Cl0.5OH0.5
A
H
N
R
N
N
(C
3
H
7
NO)
4
A
H
U
G
R
N
U
(H
2
O)
3
}
1
:
elemental analysis
ꢀ
1
.90 kJmol (Figure 9). Thus, the BET surface area and the
calcd (%) for M =1069.93: C 40.07; H 4.86; N 5.19; found: C 39.57; H
r
pore volume are enhanced on going from 2a to 2b (i.e., on
4.11; N 5.42%.
2
ꢀ1
3
ꢀ1
removal of coordinated water) from 1233 m g /0.62 cm g
Synthesis of 2: Scandium trichloride hydrate (0.027 g, 0.135 mmol) and
2
ꢀ1
3
ꢀ1
H L (0.020 g, 0.045 mmol) were mixed and dispersed in a mixture of di-
3
and 1511 m g /0.76 cm g , respectively. Also, the H ad-
2
methylformamide (3.0 mL), tetrahydrofuran (4.0 mL), dichloromethane
sorption isotherms at 78 K show a corresponding improve-
ment in total storage capacity on going from 2a to 2b. At
(
3.0 mL), water (3.0 mL) and concentrated nitric acid (68%, 3 drops).
The reaction mixture was sealed and heated in a pressure tube to 1208C
for 48 h. The tube was cooled to room temperature over a period of 12 h.
The colourless crystalline product was separated by filtration, washed
with DMF (5.00 mL) and dried briefly in air (71% yield based on the
2
0 bar, H capacity increases by one quarter from 1.99 wt%
2
to 2.64 wt%, and the H adsorption enthalpy also increases
2
ꢀ
1
from 2.59 to 6.90 kJmol . Thus, from the IR analyses and
the N and H adsorption data, the generation of free metal
ligand). Elemental analytical data corresponds to {[Sc
(H O) (DMF)} : elemental analysis calcd (%) for M =1254.88: C 54.51;
H 4.33; N 1.12; found: C 54.87; H 4.78; N 1.15%.
3 2 2 3
O(L) ACHTUNTGRENNUNG( H O) ]OH-
2
2
A
H
U
G
R
N
U
G
2
5
A
H
U
G
R
N
U
G
1
r
coordination sites on 2 after an appropriate solvation and
thermal treatment provides a material with higher surface
area, pore volume, H uptake and H heat of adsorption.
X-ray crystallography: Intensity data for 1 were collected at 150(2) K on
a Bruker SMART APEX CCD area-detector diffractometer using graph-
ite-monochromated MoKa radiation. A colourless crystal was mounted in
a film of Fomblin YR1800 perfluoropolyether (Lancaster) on a dual-
stage glass fibre immediately after removal from the mother liquid.
2
2
Conclusion
Crystal data for 1: Sc
3 23.5 36 4 r
O C H52.5Cl0.5N ; M =1069.93; hexagonal; space
group P6 /mmc (No. 194); a=b=14.056(2), c=18.099(4) ꢁ; V=
3
III
We have synthesised two Sc metal–organic frameworks in-
corporating the same trinuclear [Sc (O)(O CR) ] building
3
ꢀ3
ꢀ1
3
096.8(9) ꢁ ; Z=2; Dcalcd =1.147 gcm ; m=0.407 mm ; of 18126 reflec-
tions collected, 1382 were independent with Rint =0.121 and 1084 reflec-
tions with [I>2s(I)] and final R [I>2s(I)]=0.0592; wR (all data)=
AHCTUNGTRENNUNG
3
2
6
block. This work represents the first examples of the use of
a m -oxo bridged trinuclear Sc building block to construct
frameworks that exhibit permanent porosity and H adsorp-
1
2
III
0.158; goodness of fit=0.96. The structure was solved by direct methods
3
and subsequent difference Fourier synthesis, and was refined by using the
2
[49]
SHELXTL software package. The ligand H atoms were placed in ide-
tion properties. After an appropriate thermal treatment on
the acetone-exchanged sample 2, the generation of free
metal coordination sites has been achieved thus enhancing
alised positions and refined by using a riding model. The H atoms of the
coordinated H O molecules were located in a difference Fourier map. It
2
was not possible to localise either chloride anions (derived from the start-
3 2
ing material, ScCl ·xH O) or hydroxide anions, although their presence is
H uptake and heat of adsorption. Although 1 and 2 are
2
[50]
required to achieve charge neutrality. PLATON/SQUEEZE was used
to calculate the diffraction contributions of the solvent molecules in
order to produce a set of solvent-free diffraction intensities. The final for-
based upon the same metal cluster, only in the case of
framework 2 is it possible, in our hands, to access free metal
coordination sites. We suggest that this is linked to the dif-
ference in pore size between the two frameworks and the
more hydrophobic environment within framework 2.
[50]
mula was calculated from the SQUEEZE results combined with ele-
mental analysis and XPS data. Diffraction data for 2 were collected at
1
20(2) K on Beamline I19 of the synchrotron at the Diamond Light
Source using a Rigaku Saturn 724+ area-detector diffractometer: a
colourless crystal was mounted in a loop by using Fomblin after removal
from the mother liquid.
AHCTUNGTRENNUNG
Crystal data for 2: Sc
P62c (No. 190); a=b=31.470(4), c=16.843(3) ꢁ; V=14446(4) ꢁ ; Z=6;
3
O
23
C
57
H
54N, MW =1254.88; hexagonal; space group
¯
3
Chem. Eur. J. 2010, 16, 13671 – 13679
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
13677

M. Schrçder, N. R. Champness et al.
ꢀ
3
ꢀ1
D
calcd =0.865 gcm ; m=0.255 mm ; of 26384 reflections collected, 8207
were independent with Rint =0.120 and 5027 reflections with [I>2s(I)]
and final R [I> 2s(I)]=0.0852; wR (all data)=0.215, goodness of fit=
.004. The details for data collection are included are included in CIF
[6] a) R. Q. Zhong, R. Q. Zou, M. Du, L. Jiang, T. Yamada, G. Maruta,
S. Takeda, Q. Xu, CrystEngComm 2008, 10, 605; b) D. Maspoch, D.
Ruiz-Molina, J. Veciana, Chem. Soc. Rev. 2007, 36, 770.
[7] L. Zhang, Y. Y. Qin, Z. J. Li, Q. P. Lin, J. K. Cheng, J. Zhang, Y. G.
Yao, Inorg. Chem. 2008, 47, 8286.
[8] C. J. Winter, Int. J. Hydrogen Energy 2005, 30, 681.
[9] A. Midilli, M. Ay, I. Dincer, M. A. Rosen, Renewable Sustainable
Energy Rev. 2005, 9, 255.
1
2
1
files in Supplementary Information. The structure was solved by direct
methods and developed by difference Fourier techniques by using the
SHELXTL software package. The H atoms on the ligand were placed
in idealised positions and were refined by using a riding model. It was
not possible to localise any hydroxide anions, although their presence is
required to achieve charge neutrality. We employed PLATON/
[47]
[10] X. Lin, J. Jia, P. Hubberstey, M. Schrçder, N. R. Champness, Cryst-
AHCTUNGTRENNUNGE ngComm 2007, 9, 438.
[
50]
SQUEEZE
to calculate the contribution to the diffraction from the
solvent molecules and thereby produced a set of solvent-free diffraction
[11] a) M. Dinc a˘ , J. R. Long, Angew. Chem. 2008, 120, 6870; Angew.
Chem. Int. Ed. 2008, 47, 6766; b) X. Lin, I. Telepeni, A. J. Blake, A.
Dailly, C. M. Brown, J. M. Simmons, M. Zoppi, G. S. Walker, K. M.
Thomas, T. J. Mays, P. Hubberstey, N. R. Champness, M. Schrçder, J.
Am. Chem. Soc. 2009, 131, 2159.
[12] a) M. Dinc a˘ , W. S. Han, Y. Liu, A. Dailly, C. M. Brown, J. R. Long,
Angew. Chem. 2007, 119, 1441; Angew. Chem. Int. Ed. 2007, 46,
1419; b) M. Dinc a˘ , J. R. Long, J. Am. Chem. Soc. 2007, 129, 11172.
[13] a) M. Dinc a˘ , J. R. Long, J. Am. Chem. Soc. 2005, 127, 9376; S. S.
Kaye, J. R. Long, J. Am. Chem. Soc. 2005, 127, 6506; b) Y. Liu, H.
Kabbour, C. M. Brown, D. A. Neumann, C. C. Ahn, Langmuir 2008,
24, 4772; c) J. L. C. Rowsell, O. M. Yaghi, J. Am. Chem. Soc. 2006,
128, 1304.
[
50]
intensities. The final formula was calculated from the SQUEEZE re-
sults combined with elemental analysis and XPS data. CCDC-769527 (1)
and 769528 (2) 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.
Gas adsorption measurements: Hydrogen and nitrogen absorption was
measured in a Hiden Isochema Intelligent Gravimetric Analyser (IGA-
03), which is an ultra-high-vacuum, clean instrument with a diaphragm
and turbo pumping system, and is equipped with a micro-gram balance,
and 2 mbar, 100 mbar and 20 bar pressure transducers. A liquid nitrogen
Dewar vessel was employed for measurements at low temperature. IG-
ASwin systems software v.1.03.143 (Hiden Isochema, 2004) were used to
fit all isotherm data points by using a linear driving force model when
0
[14] Y. L. Liu, J. F. Eubank, A. J. Cairns, J. Eckert, V. C. Kravtsov, R.
Luebke, M. Eddaoudi, Angew. Chem. 2007, 119, 3342; Angew.
Chem. Int. Ed. 2007, 46, 3278.
>
98% equilibration had been reached. All changes in the sample weight
were corrected for buoyancy effects. Hydrogen was purified by using cal-
cium aluminosilicate and activated carbon adsorbents in order to remove
impurities and trace amounts of water.
[15] W. Yang, X. Lin, J. Jia, A. J. Blake, C. Wilson, P. Hubberstey, N. R.
Champness, M. Schrçder, Chem. Commun. 2008, 359.
[16] S. K. Bhatia, A. L. Myers, Langmuir 2006, 22, 1688.
[
[
[
[
17] H. Chun, D. N. Dybtsev, H. Kim, K. Kim, Chem. Eur. J. 2005, 11,
3
521.
18] B. L. Chen, M. Eddaoudi, S. T. Hyde, M. OꢃKeeffe, O. M. Yaghi, Sci-
ence 2001, 291, 1021.
19] Y. W. Li, R. T. Yang, J. Am. Chem. Soc. 2006, 128, 8136; K. L. Mul-
fort, J. T. Hupp, J. Am. Chem. Soc. 2007, 129, 9604.
20] M. Dinc a˘ , A. Dailly, Y. Liu, C. M. Brown, D. A. Neumann, J. R.
Long, J. Am. Chem. Soc. 2006, 128, 16876.
Acknowledgements
We thank the EPSRC and the University of Nottingham for support and
funding, and Diamond Light Source for access to Beamline I19. M.S.
gratefully acknowledges receipt of a Royal Society Wolfson Merit Award
and an ERC Advanced Grant. I.A.I. thanks CONACyT Mexico for
scholarship funding.
[21] a) X. Lin, J. Jia, X. B. Zhao, K. M. Thomas, A. J. Blake, G. S.
Walker, N. R. Champness, P. Hubberstey, M. Schrçder, Angew.
Chem. 2006, 118, 7518; Angew. Chem. Int. Ed. 2006, 45, 7358; b) Y.
Yan, I. Telepeni, S. Yang, X. Lin, W. Kockelmann, A. Dailly, A. J.
Blake, W. Lewis, G. S. Walker, D. R. Allan, S. A. Barnett, N. R.
Champness, M. Schrçder, J. Am. Chem. Soc. 2010, 132, 4092.
[
22] C. Serre, F. Millange, C. Thouvenot, M. Nogues, G. Marsolier, D.
Louer, G. Fꢂrey, J. Am. Chem. Soc. 2002, 124, 13519.
23] G. Fꢂrey, Science 2005, 310, 1119.
[
1] a) N. R. Champness, M. Schrçder, Curr. Opin. Solid State Mater. Sci.
1
1
998, 3, 419; P. J. Hagrman, D. Hagrman, J. Zubieta, Angew. Chem.
999, 111, 2798; Angew. Chem. Int. Ed. 1999, 38, 2639; b) A. K.
[
[
24] S. R. Miller, P. A. Wright, C. Serre, T. Loiseau, J. Marrot, G. Fꢂrey,
Chem. Commun. 2005, 3850.
Cheetham, G. Fꢂrey, T. Loiseau, Angew. Chem. 1999, 111, 3466;
Angew. Chem. Int. Ed. 1999, 38, 3268; c) M. E. Davis, Nature 2002,
[
25] J. Perles, M. Iglesias, C. Ruiz-Valero, N. Snejko, Chem. Commun.
4
17, 813; d) C. Janiak, Dalton Trans. 2003, 2781; e) S. L. James,
2
003, 346.
Chem. Soc. Rev. 2003, 32, 276; f) R. J. Hill, D. L. Long, P. Hubber-
stey, M. Schrçder, N. R. Champness, J. Solid State Chem. 2005, 178,
[26] K. Barthelet, D. Riou, G. Fꢂrey, Chem. Commun. 2002, 1492.
[27] K. Barthelet, D. Riou, M. Nogues, G. Fꢂrey, Inorg. Chem. 2003, 42,
1739.
2
414; g) B. Panella, M. Hirscher, Adv. Mater. 2005, 17, 538; h) R. J.
Hill, D.-L. Long, N. R. Champness, P. Hubberstey, M. Schrçder,
Acc. Chem. Res. 2005, 38, 335; i) M. W. Hosseini, Acc. Chem. Res.
[28] a) A. C. Sudik, A. P. Cꢄtꢂ, O. M. Yaghi, Inorg. Chem. 2005, 44, 2998;
b) P. Horcajada, S. Surblꢂ, C. Serre, D. Y. Hong, Y. K. Seo, J. S.
Chang, J. M. Greneche, I. Margiolaki, G. Fꢂrey, Chem. Commun.
2007, 2820.
[29] S. A. Cotton, Polyhedron 1999, 18, 1691.
[30] J. Perles, M. Iglesias, M. A. Martin-Luengo, M. A. Monge, C. Ruiz-
Valero, N. Snejko, Chem. Mater. 2005, 17, 5837.
2
4
005, 38, 313; j) S. Natarajan, S. Mandal, Angew. Chem. 2008, 120,
876; Angew. Chem. Int. Ed. 2008, 47, 4798; k) J. Lee, O. K. Farha,
J. Roberts, K. A. Scheidt, S. T. Nguyen, J. T. Hupp, Chem. Soc. Rev.
009, 38, 1450;l) X. Lin, N. R. Champness, M. Schrçder in Topics in
Current Chemistry, (Ed.: M. Schrçder), Springer, Heidelberg, 2010,
93, pp. 35–76.
2
2
[
2] a) R. E. Morris, P. S. Wheatley, Angew. Chem. 2008, 120, 5044;
Angew. Chem. Int. Ed. 2008, 47, 4966; b) J. R. Li, R. J. Kuppler,
H. C. Zhou, Chem. Soc. Rev. 2009, 38, 1477.
[31] J. Perles, M. Iglesias, C. Ruiz-Valero, N. Snejko, J. Mater. Chem.
2004, 14, 2683.
[32] S. R. Miller, E. Lear, J. Gonzalez, A. M. Z. Slawin, P. A. Wright, N.
Guillou, G. Fꢂrey, Dalton Trans. 2005, 3319.
[33] P. D. C. Dietzel, R. Blom, H. Fjellvag, Dalton Trans. 2006, 2055.
[34] F. Gꢅndara, B. Gomez-Lor, M. Iglesias, N. Snejko, E. Gutierrez-
Puebla, A. Monge, Chem. Commun. 2009, 2393.
[35] J. Perles, N. Snejko, M. Iglesias, M. A. Monge, J. Mater. Chem. 2009,
19, 6504.
[
[
[
3] A. Henschel, K. Gedrich, R. Kraehnert, S. Kaskel, Chem. Commun.
2
008, 4192.
4] M. Alvaro, E. Carbonell, B. Ferrer, F. Xamena, H. Garcia, Chem.
Eur. J. 2007, 13, 5106.
5] P. Ren, M. L. Liu, J. Zhang, W. Shi, P. Cheng, D. Z. Liao, S. P. Yan,
Dalton Trans. 2008, 4711.
13678
www.chemeurj.org
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 13671 – 13679

Porous Sc Metal–Organic Frameworks
FULL PAPER
[
36] a) B. Moulton, J. J. Lu, R. Hajndl, S. Hariharan, M. J. Zaworotko,
[44] a) Y. Tateyama, Y. Ohki, Y. Suzuki, A. Ouchi, Bull. Chem. Soc. Jpn.
1988, 61, 2214; b) H. R. Webb, M. J. Hardie, C. L. Raston, Chem.
Eur. J. 2001, 7, 3616; c) D.-L. Long, R. J. Hill, A. J. Blake, N. R.
Champness, P. Hubberstey, C. Wilson, M. Schrçder, Chem. Eur. J.
2005, 11, 1384.
Angew. Chem. 2002, 114, 2945; Angew. Chem. Int. Ed. 2002, 41,
2
821; b) M. Eddaoudi, J. Kim, D. Vodak, A. Sudik, J. Wachter, M.
OꢃKeeffe, O. M. Yaghi, Proc. Natl. Acad. Sci. USA 2002, 99, 4900;
c) H. Li, M. Eddaoudi, M. OꢃKeeffe, O. M. Yaghi, Nature 1999, 402,
2
76.
[45] a) J. D. Ayala, G. Vicentini, G. Bombieri, J. Alloys Compd. 1995,
225, 357; b) W. Yi, S. Xudong and Q. Guanming, J. Rare Earths
2007, 25, 68.
[46] a) X. B. Zhao, B. Xiao, A. J. Fletcher, K. M. Thomas, D. Bradshaw,
M. J. Rosseinsky, Science 2004, 306, 1012; b) H. J. Choi, M. Dinc a˘ ,
J. R. Long, J. Am. Chem. Soc. 2008, 130, 7848; c) S. Yang, X. Lin,
A. J. Blake, G. S. Walker, P. Hubberstey, N. R. Champness, M.
Schrçder, Nature Chem. 2009, 1, 487.
[
37] a) G. Fꢂrey, C. Serre, C. Mellot-Draznieks, F. Millange, S. Surblꢂ, J.
Dutour, I. Margiolaki, Angew. Chem. 2004, 116, 6456; Angew.
Chem. Int. Ed. 2004, 43, 6296; b) S. Surblꢂ, F. Millange, C. Serre, T.
Duren, M. Latroche, S. Bourrelly, P. L. Llewellyn, G. Fꢂrey, J. Am.
Chem. Soc. 2006, 128, 14889.
[
[
38] C. Serre, F. Millange, S. Surblꢂ, G. Fꢂrey, Angew. Chem. 2004, 116,
6
445; Angew. Chem. Int. Ed. 2004, 43, 6285.
39] J. Jia, X. Lin, C. Wilson, A. J. Blake, N. R. Champness, P. Hubber-
[47] a) L. Czepirski, J. Jagiello, Chem. Eng. Sci. 1989, 44, 797; J. Jagiello,
T. J. Bandosz, J. A. Schwarz, Langmuir 1996, 12, 2837; b) A. Anson,
J. Jagiello, J. B. Parra, M. L. Sanjuan, A. M. Benito, W. K. Maser,
M. T. Martinez, J. Phys. Chem. B 2004, 108, 15820; c) X. B. Zhao, S.
Villar-Rodil, A. J. Fletcher, K. M. Thomas, J. Phys. Chem. B 2006,
110, 9947; d) X. B. Zhao, B. Xiao, A. J. Fletcher, K. M. Thomas, J.
Phys. Chem. B 2005, 109, 8880; e) J. H. Cole, D. H. Everett, C. T.
Marshall, A. R. Paniego, J. C. Powl, F. Rodrigue, J. Chem. Soc.
Chem. Soc. Faraday Trans. I 1974, 70, 2154; f) I. P. O’koye, M.
Benham, K. M. Thomas, Langmuir 1997, 13, 4054; g) C. R. Reid,
I. P. OꢃKoye, K. M. Thomas, Langmuir 1998, 14, 2415; h) C. R. Reid,
K. M. Thomas, Langmuir 1999, 15, 3206; i) C. R. Reid, K. M.
Thomas, J. Phys. Chem. B 2001, 105, 10619.
stey, G. Walker, E. J. Cussen, M. Schrçder, Chem. Commun. 2007,
8
40.
[
[
40] C. Volkringer, T. Loiseau, Mater. Res. Bull. 2006, 41, 948.
41] T. Loiseau, L. Lecroq, C. Volkringer, J. Marrot, G. Fꢂrey, M.
Haouas, F. Taulelle, S. Bourrelly, P. L. Llewellyn, M. Latroche, J.
Am. Chem. Soc. 2006, 128, 10223.
[
[
42] C. Volkringer, T. Loiseau, G. Fꢂrey, C. M. Morais, F. Taulelle, V.
Montouillout, D. Massiot, Microporous Mesoporous Mater. 2007,
1
05, 111.
43] a) A. J. Blake, N. R. Champness, P. Hubberstey, W.-S. Li, M. A.
Withersby, M. Schrçder, Coord. Chem. Rev. 1999, 183, 117; b) M. A.
Withersby, A. J. Blake, N. R. Champness, P. A. Cooke, P. Hubber-
stey, A. L. Realf, S. J. Teat, M. Schrçder, J. Chem. Soc. Dalton Trans.
[48] Y. Y. Sun, Y. H. Kim, S. B. Zhang, J. Am. Chem. Soc. 2007, 129,
12606.
2
000, 3261; c) A. J. Blake, N. R. Brooks, N. R. Champness, M. Crew,
L. R. Hanton, P. Hubberstey, P. C. Simon, M. Schrçder, J. Chem.
Soc. Dalton Trans. 1999, 2813; d) D. L. Long, A. J. Blake, N. R.
Champness, M. Schrçder, Chem. Commun. 2000, 2273; e) A. J.
Blake, F. A. Devillanova, R. O. Gould, W. S. Li, V. Lippolis, S. Par-
sons, C. Radek, M. Schrçder, Chem. Soc. Rev. 1998, 27, 195; f) A. N.
Khlobystov, M. T. Brett, A. J. Blake, N. R. Champness, P. M. W. Gill,
D. P. OꢃNeill, S. J. Teat, C. Wilson, M. Schrçder, J. Am. Chem. Soc.
[49] G. M. Sheldrick, Acta Crystallogr. Sect. A 2008, 64, 112.
[50] a) P. v der Sluis, A. L. Spek, Acta Crystallogr. Sect. A 1990, 46, 194;
b) A. L. Spek, J. Appl. Crystallogr. 2003, 36, 7.
Received: April 13, 2010
2
003, 125, 6753.
Published online: October 19, 2010
Chem. Eur. J. 2010, 16, 13671 – 13679
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
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