Multinuclear zinc pentafluorobenzene carboxylates: Synthesis, characterization, and hydrogen storage capability

Article abstract of DOI:10.1021/om100703c

Three zinc carboxylate complexes, [(C₆F₅Zn) ₄Zn(Ar¹)₆]?1.5toluene, [(C ₆F₅Zn)₄Zn(Ar²)₆] ?2toluene, and [(Ar³) ₆Zn₄

Full text of DOI:10.1021/om100703c

Organometallics 2010, 29, 6129–6132 6129
DOI: 10.1021/om100703c
Multinuclear Zinc Pentafluorobenzene Carboxylates: Synthesis,
Characterization, and Hydrogen Storage Capability
Carl Redshaw,*,† Surajit Jana,† Congxiao Shang,† Mark R. J. Elsegood,‡ Xuesong Lu,§ and
Zheng Xiao Guo§
†Energy Materials Laboratory, School of Chemistry and School of Environmental Sciences, The University
of East Anglia, NR4 7TJ, U.K., ‡Chemistry Department, Loughborough University, Loughborough,
Leicestershire, LE11 3TU, U.K., and Department of Chemistry, University College London, WC1H 0AJ, U.K.
§
Received July 16, 2010
Summary: Three zinc carboxylate complexes, [(C6F5Zn)4-
Zn(Ar1)6] 1.5toluene, [(C6F5Zn)4Zn(Ar2)6] 2toluene, and
groups enforce a low coordination number at the metal
centers, leading to dimeric [EtZn(μ2-O2CR)]2.9 Mitzel et al.
reported the pentanuclear zinc hydroxylamide cluster [(iPrZn)4-
Zn(ONMe2)6],10 comprising an octahedral-based structure
with all six O,N ligands O-bound to the central Zn2þ; similar
findings were observed in the cadmium hydroxylamide
cluster [(MeCd)4Cd(ONEt2)6].11 Lewinski et al. reported
the alkylzinc carboxylate [EtZn(O2CPh)]6, a precursor to
zinc oxocarboxylates [Zn4O(O2CPh)6] and the sulfido-
carboxylates [Zn3(μ3-S)(OOCPh)(thf)]2.12 The double tetra-
hedral core complex [Zn7O2(O2CMe)10(1-Meim)2] (1-Meim =
1-methylimidazole) has been isolated from the reaction of
3
3
[(Ar3)6Zn4(μ4-O)] MeCN (where Ar1=2-chlorobenzoic acid
3
(1), Ar2 = 2,4,6-trimethylbenzoic acid (2), and Ar3 = 3-
dimethylaminobenzoic acid (3)), have been prepared from the
reaction of (C6F5)2Zn toluene and the corresponding func-
3
tionalized benzoic acid. Complexes 1-3 were structurally
characterized and screened for hydrogen absorption (uptake
<0.3 wt %).
Zinc carboxylates are of great interest owing to their role
in biochemical systems, catalysis, and materials chemistry.
For instance, alkoxyzinc carboxylates are attracting atten-
tion owing to their importance as highly active catalysts
for the polymerization or copolymerization of a wide range
of organic monomers.1 Recently, they have been utilized as
structural units/nodes in metal-organic polymers (MOPs)
and frameworks (MOFs); such systems have shown promis-
ing adsorption behavior with a variety of small molecules
including methane, nitrogen, and hydrogen.2-4 A variety of
related alkylzinc complexes containing carboxylate-based
ligands have also been prepared, most notably alkyl(R)zinc
carbamato complexes, [RZn(O2CNR02)], and alkylzinc
carboxylates for which the carboxylate group contains a
second coordinating functionality, [RZn(O2CR0X)] (X = OH,
NH2, SH).5-8 The alkylzinc carbamato species, prepared by
CO2 insertion into Zn-N bonds, form discrete tetramers of
the type [MeZn(μ3-O2CNR02)]4, which become dimers of the
form [MeZn(μ2-O2CNR02)(py)]2 on the addition of pyridine
(py) (NR02 = N(iPr)2, N(iBu)2, and piperidinyl). Dickie et al.
reported the reaction of diethylzinc with 2,6-bis(2,4,6-tri-
methylphenyl)benzoic acid, in which the bulky carboxylate
Zn(OAc)2 H2O and 1-methylimidazole in refluxing aceto-
3
nitrile.13 More recently, Shaffer and Williams et al. reported
the pentanuclear alkylzinc carboxylate [Zn5(O2CCH3)6(Et)4],
formed by the reaction of diethylzinc with zinc acetate.14
In zinc-based MOFs such as MOF-5 (derived from ter-
ephthalic acid and zinc(II) ions), there has been much
discussion as to where the hydrogen is adsorbed. For exam-
ple, neutron powder diffraction and first-principles calcula-
tions, backed up by other studies, revealed that the zinc oxide
node was primarily responsible for H2 uptake, with the organic
linker playing only a secondary role.15 Given the aforemen-
tioned utility of zinc carboxylate clusters as nodes in MOF
construction and the reports that the node was pivotal to H2
adsorption, we have embarked upon a program of synthesiz-
ing and screening potential new nodes. Here, we report three
new zinc carboxylate complexes, prepared via the reaction of
(C6F5)2Zn toluene with functionalized benzoic acids, namely,
3
2-chlorobenzoic acid, 2,4,6-trimethylbenzoic acid, and 3-di-
methylaminobenzoic acid. Crystal structure determinations
reveal, in the first two cases, rare pentanuclear structural
motifs (see Scheme 1), while in the latter case, the structure is
*Corresponding author. E-mail: carl.redshaw@uea.ac.uk.
(1) (a) Kuran, W. Principles of Coordination Polymerization; Wiley:
Chichester, 2001; Chapter 9. (b) Coates, W.; Moore, D. R. Angew. Chem.
2008, 116, 6784. Angew. Chem., Int. Ed. 2004, 43, 6618.
(2) Yaghi, O. M.; O’Keefe, M.; Ockwig, N. W.; Chae, H. K.;
Eddaoudi, M.; Kim, J. Nature 2003, 423, 705.
(9) Dickie, D. A.; Jennings, M. C.; Jenkins, H. A.; Clyburne, J. A.
Inorg. Chem. 2005, 44, 828.
(10) Ullrich, M.; Berger, R. J. F.; Lustig, C.; Frohlich, R.; Mitzel,
€
N. W. Eur. J. Inorg. Chem. 2006, 4219.
€
(11) Jana, S.; Frohlich, R.; Hepp, A.; Mitzel, N. W. Organometallics
(3) Kaye, S. S.; Dailly, A.; Yaghi, O. M.; Long, J. R. J. Am. Chem.
Soc. 2007, 129, 14176.
2008, 27, 1348.
(4) Huang, L.; Wang, H.; Chen, J.; Wang, Z.; Sun, J.; Zhao, D.; Yan,
Y. Microporous Mesoporous Mater. 2003, 58, 105.
(5) Redshaw, C.; Elsegood, M. R. J. Angew. Chem., Int. Ed. 2007, 46,
7453.
(12) Lewinski, J.; Bury, W.; Dutkiewicz, M.; Maurin, M.; Justyniak,
I.; Lipkowski, J. Angew. Chem., Int. Ed. 2008, 47, 573.
(13) Lalioti, N.; Raptopoulou, C. P.; Terzis, A.; Aliev, A. E.;
Perlepes, S. P.; Gerothanassis, I. P.; Manessi-Zoupa, E. Chem. Commun.
1998, 1513.
(6) Tang, Y.; Kassel, W. S.; Zakharov, L. N.; Rheingold, A. L.;
Kemp, R. A. Inorg. Chem. 2005, 44, 359.
(14) Orchard, K. L.; White, A. J. P.; Shaffer, M. S. P.; Williams, C. K.
Organometallics 2009, 28, 5828.
(15) (a) Yildirim, T.; Hartman, M. R. Phys. Rev. Lett. 2005, 95,
215504. (b) Roswell, J. L. C.; Spencer, E. C.; Eckert, J.; Howard, J. A. K.;
Yaghi, O. Science 2005, 309, 1350.
(7) Hursthouse, M. B.; Malik, M. A.; Motevalli, M.; O’Brien, P.
J. Chem. Soc., Chem. Commun. 1991, 1690.
(8) Boyle, T. J.; Pratt, H. D. I.; Alam, T. M.; Headley, T.; Rodriguez,
M. A. Eur. J. Inorg. Chem. 2009, 855.
r
2010 American Chemical Society
Published on Web 10/19/2010
pubs.acs.org/Organometallics

6130 Organometallics, Vol. 29, No. 22, 2010
Redshaw et al.
Scheme 1
akin to the Zn4(μ4-O) building block that has been employed
to great effect by Yaghi and others.2-4
A diagram of the core (for 1) is shown in Figure 1 and
reveals how the peripheral zinc atoms form a tetrahedron.
Each of these zinc centers is four-coordinate and possesses
a C6F5 group. The six carboxylate groups link the four zinc
ions approximately along the edges of the tetrahedron. For
each of the carboxylate groups, one oxygen bonds to only
one of Zn(2)-Zn(5), while the other oxygen bridges one of
Zn(2)-Zn(5) plus the central, pseudo-octahedral, zinc (Zn(1))
˚
center. The Zn-O bonds in 1 [1.975(3)-2.135(2) A] are simi-
lar to those reported in [Zn5(OAc)6(Et)4] [1.997(2)-2.1695(17)
14
10
˚
˚
A] and [(iPrZn)4Zn(ONMe2)6] (1.974(2)-2.205(2) A),
˚
Figure 1. (a) Core structure of 1 highlighting the approximately
tetrahedral arrangement of the peripheral zinc atoms {note:
thick black lines are not bonds}. Ellipsoids are drawn at the 50%
probability level. (b) Packing of 1.
with those to the central Zn(1) [2.061(2)-2.135(2) A] being
generally longer than those to the four-coordinate zinc ions
[1.975(3)-2.099(2) A]. There are four significant pairwise
intramolecular π-π interactions involving a C6F5 ring with
˚
a chlorobenzene ring with significant C C separations in
˚
the range 3.25 to 3.60 A. There are also a number of inter-
molecular π-π interactions, parallel to the b axis, whereby the
aforementioned intramolecular π-π stacked rings form ex-
tendedstacks, effectively linking the structure intoa 3D supra-
3 3 3
and so the reaction stoichiometry was changed in favor of
excess zinc. Following a similar workup, a complex possess-
ing only four zinc centers was isolated in good yield as small
colorless crystals suitable for an X-ray crystallographic study
using synchrotron radiation. Interestingly, the core resem-
bled that found in 1 and 2, except that the central pseudo-
octahedral zinc was now missing (Figure 3), and instead the
position is occupied by a μ4-O2-. This central oxo group is
thought to result from trace water in the reaction solvent.
The Zn-O bonds to the central oxygen atom (O(1)) [1.925(2)-
molecular network. There are also two significant F
interactions between molecules, namely, F(11) F(17)
F
3 3 3
3 3 3
˚
˚
[2.825 A] and F(3) F(12) [2.756 A]. Two types of solvent-
3 3 3
filled voids are present between the clusters. In the first void, there
are two well-defined toluene molecules, which were modeled as
point atoms. Half a toluene molecule per cluster was dis-
ordered across a center of symmetry and was poorly resolved,
so it was modeled with the Platon Squeeze procedure.16 Over-
all, therefore, there are 1.5 molecules of toluene per zinc cluster.
For 2, there is one zinc complex and two molecules of
toluene in the asymmetric unit. The pentanuclear core is
closely related to that in 1, although in this case, the Zn-O
˚
1.940(2) A] are similar in length to the Zn-O bonds involv-
ꢀ
ing the carboxylate groups. We note that Palinko et al. have
recently prepared a range of Zn4O(acid)6 complexes using
ZnO, acid, and water.17
The zinc complexes were screened for hydrogen uptake at
the isothermal temperature of 90 K. MOF-5 was employed
as the reference material and was prepared according to the
method of Deng et al.18 The isothermal adsorptions of
hydrogen on materials 1-3 and MOF-5 were tested as a
function of pressure (P); see Figure 4. For all three complexes
(Figure 4b), there was a near linear increase in uptake with
increasing pressure. At 90 K and 9 bar, the hydrogen uptake
of freshly prepared MOF-5 was found to be 2.82 wt %, which
˚
bonds to the central zinc ion (Zn(1)) [2.092(2)-2.191(2) A]
are significantly longer than those to the four-coordinate
˚
zinc centers [1.971(3)-2.086(2) A]. There are four significant
groups of intramolecular interactions involving the aromatic
rings, which either pair up or in threes and align in almost
C
parallel fashion via π-π interactions with closest C
separations in the range 3.22 to 3.60 A (see Figure 2).
3 3 3
˚
In the case of 3-dimethylaminobenzoic acid, repeated reac-
tions under similar conditions failed to yield clean products,
€
(17) Otvos, S. B.; Berkesi, O.; Kortve’lyesi, T.; Palinko, I. Inorg.
€
€
ꢀ
Chem. 2010, 49, 4620.
(18) Saha, D.; Wei, Z.; Deng, S. Sep. Purif. Technol. 2009, 64, 280.
(16) Spek, A. L. Acta Crystallogr. 1990, A46, C34.

Note
Organometallics, Vol. 29, No. 22, 2010 6131
Figure 2. Molecular structure of 2 with ellipsoids drawn at the
40% probability level.
Figure 3. Molecular structure of 3 with ellipsoids drawn at the
40% probability level.
is comparable with the literature,19 while the absorption for 1
was 0.27 wt %, 2 was 0.07 wt %, and 3 was 0.02 wt %; see
Table 1. Although the hydrogen uptake of the prepared zinc
complexes is somewhat lower than that of MOF-5, it is
promising for this group of structures that hydrogen uptake
can be improved substantially through modification of
peripheral functional groups. For example, the performance
of the zinc complex 1, bearing the electronegative Cl on the
substituents, versus 2 and 3 is an order of magnitude higher
(0.27 wt % for 1 versus 0.07 wt % uptake for 2) under the
conditions employed (90 K/9 bar). We note that fluorinated
MOFs have been shown to exhibit favorable electrostatic
interactions with gases.20
In summary, complexes 1 and 2 are rare examples of
pentanuclear zinc complexes and the first to be derived from
arylcarboxylate ligands to adopt such a core. Complex 3 is a
member of the Zn4O family, which are attracting great
attention as building blocks for MOF construction. Screening
for hydrogen storage using the zinc clusters 1-3 as hosts
indicated that uptake is not very promising (<0.3 wt % uptake),
compared with a complete MOF structure (MOF-5 uptake
2.82 wt %), but can be controlled by ligand modification. The
results suggest that the hydrogen is more likely to be adsorbed
along the MOF cavities, rather than on specific binding sites.
chemical shifts are referenced to the residual protio impurity
of the deuterated solvent. IR spectra (Nujol mulls, KBr/CsI
windows) were obtained on Perkin-Elmer 577 and 457 grating
spectrophotometers. (C6F5)2Zn toluene was prepared by the
3
method of Bochmann.21 All other chemicals were obtained
commercially and used as received unless stated otherwise.
Synthesis of 1. 2-Chlorobenzoic acid (0.38 g, 2.43 mmol) and
(C6F5)2Zn toluene (1.00 g, 2.03 mmol) were heated at 80 °C for
3
12 h in toluene (30 mL). Following removal of volatiles in vacuo,
the residue was extracted into hot toluene (20 mL). The colorless
solution was stored at -20 °C to afford colorless block-shaped
crystals of 1. Yield: 0.65 g (80%). 1H NMR (CDCl3, 298 K): δ
7.98-7.04 (m, aryl H). 13C{1H} NMR (CDCl3, 100.6 MHz, 298
K): δ 133.2, 131.6, 131.4, 131.2, 130.9, 130.0, 129.5, 125.3, 125.1
(s, aryl C). 19F NMR (CDCl3, 298 K): δ -139.9 (m, 8 F, o-F),
-154.8 (triplet of triplet, 3JFF = 17.7 Hz, 4JFF = 2.5 Hz, 4 F,
p-F,), -163.2 (m, 8 F, m-F). IR (Nujol mull): ν 629 (vs), 1563 (s),
1506 (vs), 1265 (s), 1158 (s), 1072 (s), 1055 (s), 954 (vs), 863 (w),
795 (w), 754 (s) cm-1. Anal. Calcd for C66H24Cl6F20O12Zn5
(sample dried in vacuo for 12 h, - 1.5 toluene): C 41.10, H 1.25.
Found: C 40.74, H 1.08. MS: 1438 (Mþ - 2C6F5 - ClC6H4-
CO2H), 1373 (Mþ - 2C6F5 - ClC6H4CO2H - Zn).
Synthesis of 2. 2,4,6-Trimethylbenzoic acid (0.44 g, 2.68 mmol)
and (C6F5)2Zn toluene (1.10 g, 2.23 mmol) were heated at 80 °C
3
for 12 h in toluene (30 mL). Following removal of volatiles
in vacuo, the residue was extracted into hot toluene (20 mL). The
colorless solution was stored at -20 °C to afford crystals of 2.
Yield: 0.72 g (75%). 1H NMR (CDCl3, 298 K): δ 7.20-6.49 (m,
17 H, aryl H þ aryl Htoluene), 2.31 (brs, 30 H, aryl Ho-Me), 2.26 (brs,
6 H, aryl Ho-Me), 1.93 (s, 6 H, aryl HMe þ aryl Htoluene), 1.19 (brs,
Experimental Section
General Procedures. All manipulations involving zinc were
carried out under an atmosphere of nitrogen using standard
Schlenk and cannula techniques or in a conventional nitrogen-
filled glovebox. Solvents were refluxed over an appropriate
drying agent and distilled and degassed prior to use. Elemental
analyses were performed by the microanalytical services of the
School of Chemistry at The University of East Anglia. NMR
spectra were recorded on a Varian VXR 400 S spectrometer at
400 or a Gemini at 300 MHz (1H) and 282.4 MHz (19F) at 298 K;
15 H, aryl HMe). 19F NMR (CDCl3, 298 K): δ -116.1 (d, 3JFF
=
21.3 Hz, 8 F, o-F), -159.6 (t, 3JFF = 19.4 Hz, 4 F, p-F,), -164.7
(m, 8 F, m-F). IR (Nujol mull): ν 1617 (br), 1566 (s), 1505 (vs),
1263 (s), 1182 (s), 1110 (s), 1057 (s), 954 (vs), 848 (w), 791 (w), 735
(s) cm-1. Anal. Calcd for C98H82F20O12Zn5: C 54.53, H 3.83.
Found: C 54.40, H 3.84. MS: 1413 (Mþ - C6F5 - 2Me3C6H2CO2
- Zn), 1282 (Mþ - C6F5 - 2Me3C6H2CO2 - 3Zn).
Synthesis of 3. 3-Dimethylaminobenzoic acid (0.23 g, 1.38
mmol) and (C6F5)2Zn toluene (1.10 g, 2.23 mmol) were heated
3
(19) Collins, D. J.; Zhou, H.-C. J. Mater. Chem. 2007, 17, 3154.
(20) (a) Yang, C.; Wang, X. P.; Omary, M. A. J. Am. Chem. Soc.
2007, 129, 15454. (b) Yang, C.; Wang, X. P.; Omary, M. A. Angew. Chem.,
Int. Ed. 2009, 48, 2500. (c) Liu, Z. Q.; Stern, C. L.; Lambert, J. B.
Organometallics 2009, 28, 84. (d) Fernandez, C. A.; Thallapally, P. K.;
Motkuri, R. K.; Nune, S. K.; Sumrak, J. C.; Tian, J.; Liu, J. Cryst. Growth
Des. 2010, 10, 1037.
under reflux in toluene (30 mL) for 4 h. Following removal of
volatiles in vacuo, the residue was extracted into acetonitrile
(21) Walker, D. A.; Woodman, T. J.; Hughes, D. L.; Bochmann, M.
Organometallics 2001, 20, 3772.

6132 Organometallics, Vol. 29, No. 22, 2010
Redshaw et al.
Figure 4. H2 uptake of samples at 90 K: (a) MOF-5; (b) zinc nodes 1, 2, and 3.
Crystal data for 3: C56H63N7O13Zn4, M = 1303.61, triclinic,
˚
Table 1. Maximum Hydrogen Uptakes of MOFs in wt % at 9 bar
˚
˚
P1, a = 10.635(3) A, b = 12.927(4) A, c = 21.656(6) A, R =
calcd
H2 uptake/ temperature/ pressure/ density/
3
˚
81.727(3)°, β = 84.749(3)°, γ = 77.053(3)°, V = 2865.9(14) A ,
Z = 2, Dc = 1.511 g cm-3, λ = 0.6889 A, μ = 1.589 mm-1, T =
˚
material
wt%
K
bar
g/cm3
equipment
120(2) K, colorless plate; 37 270 reflections measured on Station
I19 at the Diamond Light Source using a Rigaku Saturn 724þ
detector on a Crystal Logics diffractometer; 9917 indepen-
dent (Rint = 0.0342), data corrected as above (min. and max.
transmission factors: 0.832, 0.992), structure solved by direct
methods, F2 refinement, R1 = 0.0333 for 8350 data with F2 >
2σ(F2), wR2 = 0.0976 for all data, 787 parameters. Atoms C(30),
C(31), C(32), C(35), C(36), and N(4) were modeled as disordered
over two sets of positions with major occupancy = 58.6(5)%.
Geometric and displacement parameter restraints were applied
to help model this group.
Hydrogen Absorption Analysis. The hydrogen uptake method
was referred to in ref 22. The hydrogen sorption was measured
from 0 to 10 bar at the isothermal temperature of 90 K for all
the materials, using a gas sorption analyzer, IGA-003 (Hiden
Isochema, Warrington, UK). Static mode was applied for
all the measurements. The buoyancy effect was corrected
according to the hydogen and sample densities. The Peng-
Robinson gas-state equation was used.23 MOF-5 has been
studied in the past for hydrogen uptake by other research
groups.24 Here it was prepared and tested in our laborotory
as reference sample to compare with other materials for
hydrogen storage.
MOF-5
2.82
0.27
0.07
0.02
90
90
90
90
9
9
9
9
1.92 IGA-003, static
1.80 IGA-003, static
1.56 IGA-003, static
1.75 IGA-003, static
zinc node 1
zinc node 2
zinc node 3
(20 mL). The yellowish solution was allowed to stand at -20 °C,
affording crystals of 3. Yield: 0.23 g (77%, based on acid). H
1
NMR (CDCl3, 298 K): δ 7.54 (m, 12H, arylH), 7.24 (m, 6H,
arylH), 6.86 (m, 6H, arylH), 2.96 (s, 36H, NMe2), 1.98 (s, 3H,
MeCN). IR(Nujolmull):ν 1626 (m), 1603 (w), 1588 (m), 1574 (m),
1505 (m), 1403 (s), 1261 (s), 1234 (w), 1182 (w), 1094 (bs), 1072 (s),
1051 (s), 1020 (s), 953 (m), 867 (w), 801 (s), 760 (m), 722 (w), 684
(w), 670 (w) cm-1. Anal. Calcd for C56H63N7O13Zn4: C 51.59, H
4.87, N 7.52. Found: C 51.41, H 4.83, N 7.38. MS ((EI): 1262 (Mþ),
1096 (Mþ - NMe2C6H4CO2), 932 (Mþ - 2NMe2C6H4CO2).
X-ray Structure Analysis. All crystals were transferred from
Schlenk tubes under an inert atmosphere into an inert oil and
mounted onto a glass fiber using the oil drop technique. All were
solvent dependent.
Crystal data for 1: C76.5H36Cl6F20O12Zn5, M = 2066.60,
˚
monoclinic, P21/c, a = 23.311(2) A, b = 13.5883(12) A, c =
˚
3
˚
˚
25.442(2) A, β = 102.7617(13)°, V = 7859.9(11) A , Z = 4,
Dc = 1.746 g cm-3, μ(Mo KR) = 1.816 mm-1, T = 150(2) K,
colorless block; 72 086 reflections measured on a Bruker APEX
2 CCD diffractometer, of which 17 393 were independent
(Rint = 0.0482), data corrected for absorption on the basis of
symmetry equivalent and repeated data (min. and max. transmis-
sion factors: 0.603, 0.839) and Lp effects, structure solved by direct
methods, F2 refinement, R1 = 0.0473 for 12 397 data with F2 >
2σ(F2), wR2 = 0.1370 for all data, 1046 parameters. One toluene
molecule per Zn5 cluster well defined and modeled with point atoms,
half a toluene molecule per cluster badly disordered, so modeled as a
diffuse region of electron density by the Platon Squeeze procedure.16
Acknowledgment. We thank the EPSRC (grants EP/
F062443/1, EP/F06120X/1, and EP/E040071/1 (SUPERGEN
SHEC Consortium)) and The University of East Anglia for
support. Ms. Mi Tian in the School of Environmental Sciences
at UEA is thanked for assistance with hydrogen uptake
measurements. The EPSRC Mass Spectrometry Service Cen-
tre Swansea is thanked for data. The UK EPSRC X-ray
Crystallography Service is thanked for collecting data for 3 on
Station I19 at the Diamond Light Source.
3
˚
Squeeze recovered ca. 47 electrons in a void of ca. 225 A , which is
consistent with 50 electrons in one toluene molecule.
Crystal data for 2: C98H82F20O12Zn5, M = 2158.48, triclinic,
Supporting Information Available: 40% ellipsoid plot for 1,
selected bond lengths and angles for 1-3, and CIF files are
available free of charge via the Internet at http://pubs.acs.org.
˚
P1, a = 14.3253(9) A, b = 16.3138(10) A, c = 25.7460(14) A,
˚
˚
R = 106.5017(10)°, β = 98.0313(10)°, γ = 110.5396(10)°, V =
4600.0(5) A , Z = 2, Dc = 1.558 g cm-3, μ(Mo KR) = 1.387
3
˚
mm-1, T = 150(2) K, colorless block; 43 221 reflections mea-
sured as above; 20 247 independent (Rint = 0.0548), data
corrected as above (min. and max. transmission factors: 0.779,
0.809), structure solved by direct methods, F2 refinement, R1 =
0.0467 for 12 167 data with F2> 2σ(F2), wR2 = 0.1092 for all
data, 1237 parameters.
(22) Anson, A.; Benham, M.; Jagiello, J.; Callejas, M. A.; Benito,
A. M.; Maser, W. K.; Zuttel, Z; Marinez, M. T. Nanotechnology 2004,
15, 1503.
(23) Peng, D. Y.; Robinson, D. B. Ind. Eng. Chem. 1976, 15, 59.
(24) See for example: (a) Rowsell, J. L. C.; Millward, A. R.; Park,
K. S.; Yaghi, O. M. J. Am. Chem. Soc. 2004, 126, 5666. (b) Kaye, S. S.;
Daily, A.; Yaghi, O. M.; Long, J. R. J. Am. Chem. Soc. 2007, 129, 14176.