Two octanuclear gallium metallamacrocycles of topologically different connectivities

Article abstract of DOI:10.1039/b710531b

Two topologically different metallamacrocycles - S₈ symmetric octanuclear gallium(iii) metalladiazamacrocycle and pseudo-D₄ symmetric octanuclear gallium(iii) metalladiazamacrocycle - could be prepared using two similar heteroditopic bridging ligands having asymmetrical tridentate-bidentate binding residues. The Royal Society of Chemistry.

Full text of DOI:10.1039/b710531b

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PAPER
www.rsc.org/dalton | Dalton Transactions
Two octanuclear gallium metallamacrocycles of topologically different
connectivities†‡
a
a
a
a
b
a
Mira Park, Rohith P. John, Dohyun Moon, Kyungjin Lee, Ghyung Hwa Kim and Myoung Soo Lah*
Received 10th July 2007, Accepted 6th September 2007
First published as an Advance Article on the web 18th September 2007
DOI: 10.1039/b710531b
Two topologically different metallamacrocycles—S
8
symmetric octanuclear gallium(III)
metalladiazamacrocycle and pseudo-D symmetric octanuclear gallium(III)
4
metalladiazamacrocycle—could be prepared using two similar heteroditopic bridging ligands having
asymmetrical tridentate–bidentate binding residues.
Introduction
arising out of the asymmetrical nature of the bridging ligands
6,7
(
Scheme 1).
Self-assembled metal–organic architectures are of interest be-
cause of their potential as functional materials in areas such
1
2
3
4
as molecular recognition, delivery, catalysis and storage. To
prepare architectures with the desired structures and properties,
it is important to understand the delicate factors influencing
the formation of those systems. Even though metallamacrocycles
belong to one of the simplest forms of metal–organic clusters,
there are still many difficulties in predicting the self-assembled
products from the building blocks. The metallamacrocycles can
be self-assembled using diverse metal ions and rationally designed
organic ligands in an appropriate solvent, where the organic
5
ligands serve as ditopic linkers between ditopic metal centers. The
connectivity, nuclearity, and size of the final macrocyclic system
could be determined depending on the characteristics of the ring
components such as length, rigidity and bending angle of the
ligands, and the coordination geometry of the metal ions.
We have recently reported the preparation of metalla-
diazamacrocycles—diaza-bridged metallamacrocycles—via
a
combination of a distorted octahedral manganese(III) ion and
an asymmetrical bridging ligand, N-acyl salicylhydrazide, where
the size and nuclearity of the metalladiazamacrocycle could be
modulated by controlling the steric repulsions between the ligands
1
2
Scheme 1 Schematic diagram of the ligands, H
potential chelation modes around the metal center.
3 4
L and H L , and their
6
in the macrocyclic ring system. The metal ions and the ligands
serve as bent ditopic nodes and linear ditopic linkers, respectively.
Modification of the ligand part involved in the steric repulsion by
an introduction of sterically more demanding groups has led to
metallamacrocycles with diverse nuclearities ranging from 6 to 20
metal ions. Regardless of the size, nuclearity or stereochemistry
of the metalladiazamacrocycles, the binding mode of the ligands
around the metal centers and the connectivity of the ligands
between the metal centers are the same. This happens despite the
possibility of the formation of several different linkage isomers
Here, we investigate the effect of a minimal modification in the
bridging domain of the ligand on the formation of the metalla-
macrocyclic system. We prepared two heteroditopic pentadentate
ligands having very similar but not identical asymmetrical bridging
domains: one contains a 2-hydroxyl group at the bridging domain,
and the other contains a 2-amino group (Scheme 1).
6,7
Results and discussion
2
1
N -Cyclopentylcarbonyl-2-hydroxybenzoylhydrazide (H
3
L ) and
2
2
a
N -cyclopentylcarbonyl-2-aminobenzoylhydrazide (H L ) were
Department of Chemistry and Applied Chemistry, Hanyang Univer-
4
6
sity, Ansan, Kyunggi-do, 426-791, Korea. E-mail: mslah@hanyang.ac.kr;
Tel: +82 (0)31 400 5496; Fax: +82 (0)31 436 8100
prepared using similar procedures to those reported previously.
The reaction of Ga(NO
metal to ligand ratio of 1 : 1 in MeOH–EtOH mixed solvent. Slow
diffusion of acetonitrile into the solution produced colorless crys-
tals suitable for single-crystal X-ray diffraction study.† The crys-
tallographic analysis revealed that the complex is a 24-membered
1
3
)
3
·6H
2
O with H
3
L was carried out with a
b
Pohang Accelerator Laboratory, Pohang, Kyungbook, 790-784, Korea
†
CCDC reference numbers 298633–298635. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/b710531b
Electronic supplementary information (ESI) available: ORTEP diagrams
with the numbering for the heteroatoms. See DOI: 10.1039/b710531b
‡
5
412 | Dalton Trans., 2007, 5412–5418
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Fig. 1 (a) An ORTEP diagram of the S
8
symmetric 24-membered octanuclear gallium(III) metallamacrocycle 1. (b) An ORTEP diagram of the D
4
symmetric 24-membered octanuclear gallium(III) metallamacrocycle 2.
1
octanuclear metallamacrocycle, [Ga
8
(L )
8
(H
2
O)
2
(MeOH)
6
]
1,
molecule. The formation of an octanuclear gallium(III) metalla-
macrocycle is not expected, because other similar ligands having
Ca-substituted steric domains of comparable or even smaller steric
volumes lead to metalladiazamacrocycles with higher nuclearity
which is isostructural with other octanuclear manganese or iron
metalladiazamacrocycle (Fig. 1a and Fig. S1 in the ESI‡).
6
b,7b
The pentadentate ligand bridges the metal ions using the diaza
group via simultaneous tridentate and bidentate bindings on both
sides of the bridging domain. The 24-membered macrocyclic ring
system is formed by eight cyclic repeats of the -[Ga(III)–N–N]-
unit, where the ligand serves as a trianion and the resulting
macrocycle is neutral with the tricationic gallium(III) ion as a
ring metal. This kind of back-to-back binding mode results in
6b
on combination with manganese(III) ions. The strain caused by
the repulsive interaction between the steric domains of the ligands
in the metalladiazamacrocycles could be released by an expansion
of the macrocyclic ring system with the expense of the increased
strain around the metal center caused by the ring expansion. The
lower nuclearity in the gallium(III) metallamacrocycle than in the
corresponding manganese(III) metallamacrocycle might be caused
by the larger force constants in the bond distances and angles
around the regular octahedral gallium(III) metal centers than those
around the Jahn–Teller elongated hexa-coordinate manganese(III)
centers.
an S symmetric octanuclear metalladiazamacrocycle, 1, with
8
metal centers in an alternating · · · (DK)(DK) · · · chiral sequence,
where the D or K chirality of the metal center was induced by
simultaneous tridentate and bidentate bindings around the metal
center (Fig. 2). The sixth coordination site of the octahedral
gallium ion in the metallamacrocycle is occupied by a solvent
The substitution of the hydroxyl group attached to the aromatic
ring of the ligand by an amino group while keeping all other
parts of the ligand the same may change the protonation state
of the ligand in the complex because of the difference in the
pK values of the residues. It may also alter the binding mode
a
around the metal center, which might lead to the formation of
a cationic metallamacrocycle in different binding modes around
the metal centers. To test this, we prepared another ligand
2
(
H
4
L ), in which the hydroxyl group in the bridging domain
is replaced by an amino group. Colorless crystals of 2/3 were
obtained from methanol with 1 : 1 ratio of ligand to metal.
The crystals are in two different morphologies, the major form
in a block-shaped morphology and the minor form in a plate-
shaped morphology. The crystallographic analysis† revealed that
2
the block-shaped crystal is [Ga
8
(H
2
L )
8
(MeOH)5.5(H
2
O)2.5](NO
3
)
8
,
2
(Fig. 1b and Fig. S2 in the ESI‡), and the plate-shaped crys-
2
2
tal is [Ga
8
2
(H
2
L )
8
(MeOH)
(NO
6
(H
)](NO
2
O)
2
]
2
[Ga
8
(H
2
L )
8
(MeOH)
4
(H O)
2
4
]
[
Ga
4
(H
2
L )
4
(MeOH)
3
3
3
)
27·24MeOH·2H
2
O, 3 (Fig. S3
in the ESI‡). All five crystallographically different macrocyclic
complexes in both crystals are very similar to each other. The
binding modes of the ligands in metallamacrocycle 2/3 are exactly
the same; the only difference is in the kinds and number of the
Fig. 2 A schematic diagram showing the D and K configurations for the
metal center of the propeller bidentate/tridentate binding mode, observed
in 1.
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◦
solvent molecules or anions coordinated to the macrocycles.§ The
ligand is in a doubly deprotonated dianionic state, [H L ] , in
contrast to the other ligand, which is in a triply deprotonated
tridentate-tridentate coordination mode, and 111(2) associated
2
2−
2
with a propeller bidentate–bidentate coordination mode; hence the
overall shape of metallamacrocycle 1 is like a square disc. Both the
meridional tridentate–tridentate binding mode around the metal
center and the propeller bidentate–bidentate binding mode around
the other metal center (Fig. 3) induce a chirality in the metal center,
as in the metal center with tridentate–bidentate binding mode in
complex 1 (Fig. 2). These two binding modes result in a chiral
pseudo-D symmetric octanuclear metalladiazamacrocycle, 2 and
3. The metallamacrocycles have two chemically different metal
centers with different kinds of chiral configurations, C (clockwise)
for the meridional tridentate–tridentate binding metal center and
1
3−
2
2−
trianionic state, [L ] . The ligand, [H L ] , still behaves as a
2
bridging pentadentate ligand. The tridentate coordination on one
side and bidentate coordination on the other side bridge two
1
3−
metal centers as [L ] in complex 1. The eight successions of the
diaza bridged -[Ga(III)–N–N]- unit lead to a metallamacrocyclic
structure. However, two different kinds of metal centers are
observed in 2/3, in contrast to one kind of metal center in complex
4
8
1
. The difference occurs because of the two different binding modes
2
2−
of the dianionic [H
2
L ] ligand around the metal centers, merid-
ional tridentate–tridentate coordination and propeller bidentate–
bidentate coordination, which originate from the asymmetric
nature of the bridging ligand (Fig. 3). The average M · · · M
distance in metallamacrocycle 2/3 is very similar to that in 1.
However, the M · · · M · · · M angles in 2/3 are quite different from
D for the propeller bidentate–bidentate binding metal center, where
the metal centers are in the · · · (C
A
D
B
)(C
A
D
B
) · · · chiral sequence.
Having the same bridging mode between the metal centers but
different binding modes around the metal centers led to metalla-
diazamacrocycles with two topologically different connectivities.
While the ligand connectivity in metallamacrocycle 1 can be
◦
those in 1. All angles in 1 are in the narrow range, 127–133 ,
◦
with the average value of about 131(2) and hence the overall
represented as a cyclic –
that in 2 and 3 can be represented as alternating –
–M
of the heteroditopic bridging ligands around the metal centers
have led to two topologically different octanuclear gallium(III)
metallamacrocyclic systems.
T
L
B
–M–
T
L
B
–M–
T
L
B
– linkage (Fig. 4a),
shape of metallamacrocycle 1 is like a circular disc. However, two
different binding modes around the metal centers in 2/3 led to two
B
L
T
–M –
A
T
L
B
B
–
B
L
T
– linkages (Fig. 4b).¶ These different connectivities
◦
different M · · · M · · · M angles, 158(2) associated with meridional
§
In complex 2, the solvent coordination sites of the gallium ions are
occupied by methanol, water, or statistically disordered methanol/water
molecules. In complex 3, three crystallographically independent octanu-
clear metallamacrocycles, and a half of one octanuclear metallamacrocycle
in the crystallographic C
coordination sites of the gallium ions are occupied by either methanol or
water molecules; however, in the metallamacrocycle in the crystallographic
2
axis were identified. As in 2, the solvent
¶ For convenience of representation, the asymmetric bridging ligand in the
T B
macrocycle was symbolized as L and the connectivity was represented
as an arrow, where the bidentate binding region of the ligand designated
using the subscript B is the head part of an arrow and the tridentate binding
region designated using the subscript T is the tail part (Fig. 4).
C
2
axis, a nitrate anion is ligated at the sixth coordination site of the gallium
ion per crystallographic asymmetric unit (Fig. S2 and S3 in the ESI‡).
Fig. 3 Schematic diagrams for two different types of chiral configurations around the metal centers: C/A for metal center of meridional
tridentate–tridentate binding mode and D/K for the metal center of propeller bidentate–bidentate binding mode, observed in 2.
5
414 | Dalton Trans., 2007, 5412–5418
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Fig. 4 Comparison of two octanuclear gallium(III) metallamacrocycles having topologically different connectivities. The asymmetrical heteroditopic
ligand was represented using an arrow. (a) Schematic diagram of the S
8
T B T B T B
symmetric metallamacrocycle with the cyclic – L –M– L –M– L – linkage.
(
b) Schematic diagram of the D symmetric metallamacrocycle with the alternating –
4
T
L
B
–M– –M– – linkage.
T
L
B
T B
L
Conclusions
Experimental
We were able to synthesize two topologically different gallium(III)
metalladiazamacrocycles via a controlled modification of the
building blocks. The minimal modification in the bridging domain
of the potential pentadentate ligand, while keeping all the remain-
ing part of the ligand the same, has led to different chelation modes
around the macrocyclic ring metal centers. When trianionic ligand
Materials
All reagents and solvents for syntheses were purchased from the
commercial sources and used as received.
Instrumentation
1
3−
[
L ] was used as a bridging ligand between the metal centers,
the cyclic repeat of the same tridentate–bidentate chelation mode
at the metal center led to an achiral S symmetric octanuclear
Elemental analyses (C, H, and N) were performed at the Elemental
Analysis Laboratory of the Korean Basic Science Institute on a CE
Flash EA 1112 series elemental analyzer. Melting points of well-
ground solid samples were measured using a SANYO Gallenkamp
PLC melting point apparatus. Infrared spectra were recorded as
8
metalladiazamacrocycle, which has the same topological connec-
tivity as that reported in other metalladiazamacrocycles prepared
using the same types of ligands. However, when dianionic ligand
−1
KBr pellets in the range 4000–600 cm on a BioRad FT-IR
spectrometer. ESI mass spectra were obtained using an HP Agilent
2
2−
[
H L ] was used as a bridging ligand between the metal centers,
2
the occurrence of alternate tridentate–tridentate and bidentate–
bidentate chelation modes at the metal centers led to a chiral
1
100 MSD mass spectrometer. NMR spectra were obtained using
a Varian-300 spectrometer.
pseudo-D symmetric octanuclear metalladiazamacrocycle with a
4
different connection topology. The different connectivities around
the metal centers come from the asymmetric nature of the triden-
tate and bidentate binding modes of the heteroditopic bridging
ligands.
Ligand synthesis
2
1
N -Cyclopentylcarbonyl-2-hydroxybenzohydrazide
(H
3
L ).
2.51 mL (20.2 mmol) of trimethylacetyl chloride was added
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◦
to 30 mL of chloroform solution at 0 C, containing 2.95 mL
21.0 mmol) of triethylamine and 2.25 g (20.4 mmol) of
2962(m), 2872(m), 1604(m), 1583(m), 1551(m), 1514(s), 1473(m),
1413(m), 1326(m), 1261(m), 1246(m), 1154(m), 1096(w), 1048(w),
932(w), 854(m), 758(m), 701(w), 676(w), 652(w), 485(w). X-Ray
(
cyclopentanecarboxylic acid, over a 5 min period with stirring.
The solution was slowly brought to ambient temperature. An
equivalent amount of salicylhydrazide (3.08 g, 20.0 mmol) was
added to the solution and refluxed for a day. The white precipitate
obtained was filtered and washed with small quantities of cold
quality crystals were obtained by acetonitrile vapor diffusion into
1
a solution of Ga(NO
3
)
3
·6H
2
O (37.5 mg, 0.103 mmol) and H L
3
(25.4 mg, 0.102 mmol) in methanol and ethanol (1.0 mL : 0.7 mL)
over a period of 10 d. Because a single batch yielded only a few
countable crystals, it was not possible to isolate the entire product
as crystals. The identities of the bulk isolate and the crystalline
product were confirmed to be the same by elemental and IR
spectral examination.
chloroform followed by water. Yield 3.78 g (75.9%). Mp =
◦
1
89–191 C. Anal. calc. for C13
H
16
N
2
O : C 62.89, H 6.50, N
3
1
1.28; found C 63.03, H 6.17, N 11.47%; ESI mass spectrum:
+
1
m/z of [C13
H
18
N
2
O
3
+ H] , 249.1; H-NMR (DMSO-d , d ppm)
6
1
1.92 (bs, 1H, NH) 10.56 (bs, 1H, NH), 10.11 (s, 1H, OH), 7.87
2
2
[
Ga
MeOH)
MeOH)
8
( H
2
L )
8
( MeOH )5.5( H
2
2
O )2.5]( NO
3
)
8
, 2 and [ Ga
(H O) ][Ga
(NO )](NO
8
( H
(H
2
L )
8
8
-
-
(
d, 1H, ArH), 7.43 (t, 1H, ArH), 6.94 (m, 2H, ArH), 2.71 (m,
2
(
(
6
(H
2
O)
2
][Ga
8
(H
2
2
L )
8
(MeOH)
4
2
4
8
2
L )
1
3
1
H, -CH–(CH
2
)
4
), 1.53–1.82 (m, 8H, -CH-(CH
2
) ); C-NMR
4
6
(H O)
2
2
][Ga
4
(H
2
L )
4
(MeOH)
3
3
3
)
27·24MeOH·
(
DMSO-d
6
, d ppm) 174.4, 166.0, 159.2, 134.1, 128.3, 119.1, 117.4,
2
2
H
2
O, 3. 25.2 mg (0.102 mmol) of H L was dissolved in
5 mL of MeOH in a 20 mL vial and 41.7 mg (0.115 mmol) of
4
−
1
114.6, 42.1, 30.1, 25.8. IR (KBr, cm ) 3334(m), 3313(m), 3062(m),
3017(m), 2941(m), 2865(m), 2737(m), 2589(w), 1673(m), 1636(m),
1606(s), 1548(m), 1488(s), 1457(m), 1402(m), 1385(m), 1317(w),
1317(w), 1266(m), 1240(w), 1214(m), 1156(w), 1104(m), 1062(w),
1024(w), 961(m), 876(m), 826(w), 756(m), 570(m), 530(m),
490(m).
1
Ga(NO
3
)
3
·6H
2
O was slowly added. The solution was allowed to
◦
stand for 5 days at 0 C in the refrigerator and gave colorless
crystals of at least two different morphologies: one of block-
shaped complex 2 as the major form and the other of plate-
shaped complex 3 as the minor form. The product was filtered
and freeze-dried before elemental analysis. (18.2 mg, 52.8% yield).
2
2
N -Cyclopentylcarbonyl-2-aminobenzohydrazide
(H
4
L ).
1
.27 mL (10.2 mmol) of trimethylacetyl chloride was added
Analysis data for a mixture of complex 2 and 3. Elemental
◦
2
to 40 mL of chloroform solution at 0 C, containing 1.48 mL
analysis, [Ga
8
(H
2
L )
8
(H
2
O)
8
](NO
3
)
8
·16H
2
O (C104
H
168
N
32
O
64Ga ,
8
−
1
(
10.5 mmol) of triethylamine and 1.12 mL (10.2 mmol) of
fw = 3448.41 g mol ) calc.: C 36.22, H 4.91, N 13.00%; found:
−1
cyclopentanecarboxylic acid, over a 5 min period with stirring.
The solution was slowly brought to ambient temperature. An
equivalent amount of 2-aminobenzhydrazide (1.53 g, 10.0 mmol)
was added to the solution and refluxed for a day. The white
precipitate obtained was filtered and washed with chloroform and
C 35.81, H 4.51, N 12.92%. IR (KBr pellet, cm ): 3419(br),
2960(m), 2872(w), 1602(m), 1518(m), 1499(w), 1384(s), 1086(m),
1
822(w), 758(m), 703(w), 671(w). H NMR spectrum (DMSO-d
6
,
d ppm): 9.93, 9.67, 8.04, 7.90, 7.72, 7.60, 7.52, 7.42, 7.27, 7.16,
7.06, 6.93, 6.81, 6.71, 6.50, 6.38, 5.68, 4.28, 3.16, 2.66, 1.53–1.81,
◦
1
water. Yield 1.47 g (61.2%). Mp = 188–190 C. Anal. calc. for
1.23, 1.01. H NMR spectrum (DMF-d
7
, d ppm): 9.93, 9.68, 8.10,
C
13
H
17
N
3
O
2
1
: C 63.14, H 6.93, N 16.97%, found C 63.41, H 6.89,
7.70, 7.63, 7.61, 7.46, 7.20, 6.82, 6.54, 1.80, 1.14, 0.95, 0.68.
N 16.97%; H NMR spectrum (DMSO-d
6
, d ppm): 9.93 (bs, 1H,
NH), 9.70 (bs, 1H, NH), 7.52 (d, 1H, ArH), 7.16 (t, 1H, ArH),
.71 (d, 1H, ArH), 6.50 (t, 1H, ArH), 6.40 (bs, 2H, NH ), 2.66
); C NMR
, d ppm) 175.7, 168.7, 150.5, 132.9, 128.8,
Crystallographic studies†
6
2
The crystals were coated with paratone oil because they lose
crystallinityonexposure toair. The diffractiondatawere measured
1
3
(
m, 1H, -CH–(CH
2
)
4
), 1.50–1.84 (m, 8H, -CH-(CH
)
2 4
spectrum (DMSO-d
6
˚
at 100 K with synchrotron radiation (k = 0.70000 A) on a 4AMXW
−
1
1
3
1
17.0, 115.2, 113.2, 42.8, 30.6, 26.4. IR spectrum (KBr, cm )
406(s), 3256(s), 2951(m), 2864(w), 1692(s), 1646(s), 1618(m),
521(m), 1233(m), 903(w), 744(m).
ADSC Quantum-210 detector with a Pt-coated Si double crystal
monochromator at the Pohang Accelerator Laboratory, Korea.
9
The HKL2000 (Ver. 0.98.694) was used for data collection, cell
refinement, reduction and absorption correction.
Preparation of gallium metallamacrocycles
1
Crystal structure determination for [Ga
8
L
8
(EtOH)2.5
-
1
1
[Ga
8
(L )
8
(H
2
O)
2
(MeOH)
6
], 1. 0.253 g (1.02 mmol) of H
3
L
(
N
MeOH)5.5
]
2
·5.5EtOH·12MeOH, 1. Crystal data: Ga16
C
252
H
363
-
and 0.382 g (1.05 mmol) of Ga(NO
3
)
3
·6H O were dissolved in a
2
−
1
32
O81.5, M = 6260.26 g mol , monoclinic, space group Cc,
mixture of 1.5 mL of methanol and 0.5 mL of ethanol, which
became a clear solution in 15 min on stirring. Acetonitrile was
then allowed to diffuse into this solution by vapor diffusion. A
pale orange-colored product was obtained from the reaction vial
over a period of two days. The product was filtered, washed with
small quantities of DMF, plenty of methanol, and then water, and
◦
˚
a = 49.314(10), b = 19.934(4), c = 36.554(7) A, b = 127.10(3) ,
3
˚
V = 28660(10) A , T = 90(2) K, Z = 4, l(synchrotron, k =
−
1
˚
.70000 A) 1.563 mm . 74658 reflections were collected, 74658
0
were unique. The structure of complex 1 was solved by direct
methods as the noncentrosymmetric space group Cc and could
be refined by full-matrix least-squares calculations with racemic
twin option using the SHELXTL-PLUS software package. All
attempts to solve the structure as the centrosymmetric space
was freeze-dried before elemental analysis. (0.1680 g, 58.3% yield).
10
1
Elemental data for [Ga
8
(L )
8
(H
2
O)
8
]·12H
2
O (C104
H
144
N
16
O
44Ga ,
8
−
1
fw = 2880.13 g mol ) calc.: C 43.37, H 5.04, N 7.78%; found:
−
1
C 43.37, H 4.86, N 7.57%.ꢀ IR (KBr pellet, cm ): 3436(br),
original contents of the crystals, despite several attempts. The complexes
were found to lose the solvent molecules during freeze-drying and exposure
to air and were subsequently replaced by water molecules in air. These
results are also consistent with the TGA data of complex 1 and mixture of
complex 2 and 3.
ꢀ
Even though the crystal structure analyses of complexes 1–3 suggest
that the crystals contained several solvent molecules, as either ligating or
structural solvents, the elemental analyses were not consistent with the
5
416 | Dalton Trans., 2007, 5412–5418
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View Article Online
group C2/c failed. Two octanuclear metallamacrocycles and at
least 16 non-coordinating structural solvent sites were identified
as an asymmetric unit. All non-hydrogen atoms except the atoms
of disordered groups were refined anisotropically; hydrogen atoms
except those attached to some of the disordered solvent molecules
were assigned isotropic displacement coefficients U(H) = 1.2U,
and their coordinates were allowed to ride on their respective
atoms. Several cyclopentyl parts of the ligands are statically
disordered and were refined with geometry restraints during
the least squares refinement. All sixth coordination sites of the
gallium centers are occupied by ethanol, methanol, or statistically
disordered ethanol/methanol molecules. In addition, six ethanol
and twelve methanol (or partially identified ethanol) sites per
asymmetric unit were identified and included in the least squares
refinement. Refinement of the structure converged at a final R1 =
except those attached to the solvent molecules were assigned
isotropic displacement coefficients U(H) = 1.2U (C, N), and their
coordinates were allowed to ride on their respective atoms. One
cyclopentyl group of bad geometry was refined with geometry
restraints during the least squares refinement. The solvent co-
ordination sites of the gallium ions are occupied by methanol,
water, or statistically disordered methanol/water molecules. In
addition, seven methanol and five water (or partially identified
methanol) sites per asymmetric unit were identified and included
in the least-squares refinement. The refinement converged to a final
R1 = 0.0677 and wR2 = 0.1860 for 22816 reflections of I > 2r(I).
Further structure refinement was performed after modification of
the data for the non-coordinate lattice solvent molecules with the
SQUEEZE routine of PLATON (after removing lattice solvent
11
molecules), which led to better refinement and data convergence.
Refinement of the structure converged at a final R1 = 0.0437,
wR2 = 0.1036 for 22670 reflections with I > 2r(I), R1 = 0.0653,
wR2 = 0.1098, GOF = 0.936 for all 31273 reflections. The largest
0
.0550, wR2 = 0.1484 for 57095 reflections with I > 2r(I), R1 =
.0732, wR2 = 0.1607, GOF = 0.986 for all 74658 reflections.
0
−
3
˚
The largest difference peak and hole, 1.386 and −1.127 e A
−
3
˚
respectively, were observed in the vicinities of the metal centers.
A summary of the crystal and intensity data is given in Table 1.
difference peak and hole were 0.564 and −0.547 e A , respectively.
A summary of the crystal and intensity data is given in Table 1.
2
2
Crystal structure determination for [Ga
8
(H
2
L )
8
(MeOH)5.5
-
Crystal structure determination for [Ga
8
(H
2
L )
8
(MeOH)
6
-
-
2
2
(
3
H
2
O)2.5](NO
3
−
)
8
1
, 2. Crystal data: Ga
8
C
109.5
H
146
N
31
O45, M =
(H
2
O)
2
][Ga
8
(H
2
2
L )
8
(MeOH)
(NO
193, M = 12114.25 g mol , mon-
oclinic, space group C2/c, a = 73.383(15), b = 37.028(7), c =
4
(H
2
O)
4
][Ga
8
(H
2
L )
8
(MeOH)
6
174.33 g mol , orthorhombic, space group Pna2
1
, a = 24.973(5),
(H
2
O)
2
][Ga (H
4
2
L )
4
(MeOH)
3
3
)](NO
3
)
27·24MeOH·2H
2
−1
O, 3.
3
˚
˚
b = 26.951(5), c = 27.543(6) A, V = 18538(6) A , T = 100(2) K,
Crystal data: Ga28
C
407
H
612
112
N O
−
1
˚
Z = 4, l(synchrotron, k = 0.70000 A) 1.213 mm , 56405 reflec-
tions were collected, 31273 were unique [Rint = 0.0537]. The crystal
structure of complex 2 was solved by direct methods and refined
by full-matrix least-squares calculations with the SHELXTL-
◦
3
˚
˚
40.988(8) A, b = 110.56(3) , V = 104279(36) A , T = 100(2)
−
1
˚
K, Z = 8, l(synchrotron, k = 0.70000 A) 1.522 mm , 186273
reflections were collected, 105910 were unique [Rint = 0.0480].
The crystal structure of complex 3 was solved by direct methods
and refined by full-matrix least-squares calculations with the
10
PLUS software package. An octanuclear metallamacrocycle,
seven nitrate anions and at least 12 non-coordinating structural
solvent sites were identified as an asymmetric unit. All non-
hydrogen atoms except those of the non-coordinating structural
solvent molecules were refined anisotropically; hydrogen atoms
10
SHELXTL-PLUS software package. Three crystallographically
independent octanuclear metallamacrocycles, half of one octanu-
clear metallamacrocycle in the crystallographic C
2
axis, one nitrate
Table 1 Crystallographic data for complexes 1–3
Complex
1
2
3
Empirical formula
M/g mol−
Ga16
6260.26
90(2)
C
252
H
363
N
32
O
81.5
Ga
3174.33
100(2)
8
C
109.5
H
146
N
31
O
45
Ga28
12114.25
90(2)
C
407
H
612
N
112
O
193
1
T/K
Wavelength/A˚
0.70000
0.70000
0.70000
Crystal system
Space group
A/A˚
Monoclinic
Cc
49.314(10)
19.934(4)
36.554(7)
90
127.10(3)
90
28660(10)
4
Orthorhombic
Pna2
Monoclinic
C2/c
1
a = 24.973(5)
a = 73.383(15)
b = 37.028(7)
c = 40.988(8)
90
110.56(3)
90
104279(36)
8
1.543
B/A˚
C/A˚
b = 26.951(5)
c = 27.543(6)
◦
a/
b/
90
◦
90
90
18538(6)
4
1.137
1.213
◦
c /
Volume/A˚
3
Z
−
−
3
Density (calculated)/Mg m
Absorption coefficient/mm
1.451
1.563
1
1.522
3
Crystal size/mm
Absorption correction
0.30 × 0.30 × 0.25
0.20 × 0.10 × 0.10
0.30 × 0.20 × 0.15
Empirical
Empirical
Empirical
Data/restraints/parameters
Goodness-of-fit on F
74658/272/3511
31273/11/1748
0.936
R1 = 0.0437, wR2 = 0.1036
R1 = 0.0653, wR2 = 0.1098
0.564 and −0.547
105910/13/6774
1.083
R1 = 0.0614, wR2 = 0.1745
R1 = 0.1061, wR2 = 0.1984
2.539 and −1.652
2
0.986
a
b
Final R indices [I > 2r(I)]
R1 = 0.0550, wR2 = 0.1484
R1 = 0.0732, wR2 = 0.1607
1.386 and −1.127
R indices (all data)
Largest diff. peak and hole/e A˚
−3
a
b
2
2
2
2
2
1/2
R1 = [RꢀF
o
|–|F
c
ꢀ]/[R|F
o
|]. wR2 = {[Rw(F
o
–F
c
) ]/[Rw(F
o
) ]}
.
This journal is © The Royal Society of Chemistry 2007
Dalton Trans., 2007, 5412–5418 | 5417

View Article Online
anion as coordinate ligand, 27 nitrate counter anions including
one partially identified, 27 coordinating solvent molecules, and
at least 26 additional non-coordinating structural solvent sites
were identified as an asymmetric unit. All non-hydrogen atoms
except those of the solvent molecules were refined anisotropically;
hydrogen atoms except those attached to the solvent molecules
were assigned isotropic displacement coefficients U(H) = 1.2U
2 (a) P. Horcajada, C. Serre, M. Vallet-Reg ´ı , M. Sebban, F. Taulelle and
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2
007, 19, 2679.
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Bergman and K. N. Raymond, Science, 2007, 316, 85.
4 (a) M. Eddaoudi, J. Kim, N. Rosi, D. Vodak, J. Wachter, M. O’Keeffe
and O. M. Yaghi, Science, 2002, 295, 469; (b) M. Dinc a˘ , A. Dailly,
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8227.
(
C, N), and their coordinates were allowed to ride on their
respective atoms. Several cyclopentyl parts of the ligands were
refined with statically disordered models. The solvent coordination
sites of the gallium ions are occupied by methanol, water, or
nitrate anions. An additional 24 methanol molecules, and two
water (or partially identified methanol), per asymmetric unit were
identified and included in the least-squares refinement. A couple of
nitrate anions and methanol molecules were refined with geometry
restraints during the least-squares refinement. Refinement of the
structure converged at a final R1 = 0.0614, wR2 = 0.1745 for
5 (a) S. Leininger, B. Olenyuk and P. J. Stang, Chem. Rev., 2000, 100,
8
53; (b) B. Moulton and M. J. Zaworotko, Chem. Rev., 2001, 101, 1629;
(
2
c) B. J. Holliday and C. A. Mirkin, Angew. Chem., Int. Ed., 2001, 40,
6
7823 reflections with I > 2r(I), R1 = 0.1061, wR2 = 0.1984,
022; (d) J. J. Bodwin, A. D. Cutland, R. G. Malkani and V. L. Pecoraro,
GOF = 1.083 for all 105910 reflections. The largest difference
Coord. Chem. Rev., 2001, 216–217, 489; (e) K. Severin, Chem. Commun.,
2006, 3859.
−
3
˚
peak and hole, 2.539 and −1.652 e A respectively, were observed
in the vicinities of the metal centers. A summary of the crystal and
intensity data is given in Table 1.†
6
(a) B. Kwak, H. Rhee, S. Park and M. S. Lah, Inorg. Chem., 1998, 37,
3
599; (b) R. P. John, K. Lee, B. J. Kim, B. J. Suh, H. Rhee and M. S.
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R. P. John, G. H. Kim, B. J. Suh and M. S. Lah, Inorg. Chem., 2006,
Acknowledgements
4
5, 7991.
This work was supported by KRF (KRF-2005-070-C00068),
KOSEF (R01-2007-000-10167-0) and CBMH. The authors also
acknowledge PAL for beam line use (2007-1041-08).
7
(a) S. Lin, S.-X. Liu, J.-Q. Huang and C.-C. Lin, J. Chem. Soc., Dalton
Trans., 2002, 1595; (b) S. Lin, S.-X. Liu, Z. Chen, B.-Z. Lin and S. Gao,
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and J.-Q. Huang, Angew. Chem., Int. Ed., 2001, 40, 1084.
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pp. 307.
8
9
Notes and references
1
(a) M. Yoshizawa, M. Tamura and M. Fujita, J. Am. Chem. Soc., 2004,
1
26, 6846; (b) M. Fujita, Chem. Soc. Rev., 1998, 27, 417; (c) J. M. C. A.
Kerchoffs, F. W. B. van Leeuwen, A. L. Spek, H. Kooijman, M.
10 G. M. Sheldrick, SHELXTL-PLUS, Crystal Structure Analysis Pack-
Crego-Calama and D. N. Reinhoudt, Angew. Chem., Int. Ed., 2003, 42,
age, Bruker Analytical X-ray, Madison, WI, 1997.
5
717.
11 Platon program: A. L. Spek, Acta Crystallogr., Sect. A, 1990, 46, 194.
5
418 | Dalton Trans., 2007, 5412–5418
This journal is © The Royal Society of Chemistry 2007