A porous metal-organic cage constructed from dirhodium paddle-wheels: Synthesis, structure and catalysis

Article abstract of DOI:10.1039/c5ta05592j

Self-assembly of dirhodium(ii) tetraacetate (Rh₂(OAc)₄) with a dicarboxylic acid 3,3′-(1,3-phenylenebis(ethyne-2,1-diyl))dibenzoic acid (H₂pbeddb) gives rise to a metal-organic cage (MOC) containing Rh-Rh bonds with the formula of [Rh₄(pbeddb)₄(H₂O)₂(DMAC)₂] (MOC-Rh-1). Single-crystal X-ray diffraction analysis reveals that MOC-Rh-1 shows a lantern-type cage structure, in which a pair of Rh₂(CO₂)₄ paddlewheels is linked by four diacid ligands. The dimensions of the inner cavity of MOC-Rh-1 are 9.5 × 14.8 ?² (atom-to-atom distances across opposite metal and phenyl groups of pbeddb^2-). In the solid phase, the cages are aligned by π-π stacking to form one-dimensional channels (9.5 × 11.1 ?²) through cage windows. Therefore, the crystalline samples of MOC-Rh-1 are porous with the inner and outer cavities of the cages accessible under the heterogeneous condition. MOC-Rh-1 has been fully characterized by EA, TGA, PXRD, IR, UV-vis and XPS measurements. The catalytic tests disclose that activated MOC-Rh-1 is effective in the intramolecular C-H amination of vinyl, dienyl and biaryl azides, leading to the formation of indoles, pyrroles and carbazoles, respectively, and the porous catalyst can be recycled easily and used for at least nine runs without significant loss of activity. In the nine runs, the conversions were in the range of 93-99%, whereas in the tenth run, the conversion was reduced to 78%.

Full text of DOI:10.1039/c5ta05592j

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A Porous Metal‐Organic Cage Constructed from Dirhodium
Paddle‐Wheels: Synthesis, Structure and Catalysis
Lianfen Chen,a Tao Yang,a Hao Cui,a Tao Cai,a Li Zhang,*,a Cheng‐Yong Su*,a,b
Received 00th January 20xx,
Accepted 00th January 20xx
Self‐assembly of dirhodium(II) tetraacetate (Rh2(OAc)4) with a dicarboxylic acid 3,3'‐(1,3‐phenylenebis(ethyne‐2,1‐
diyl))dibenzoic acid (H2pbeddb) gives rise to a metal‐organic cage (MOC) containing Rh‐Rh bonds with the formula of
[Rh4(pbeddb)4(H2O)2(DMAC)2] (MOC‐Rh‐1). Single‐crystal X‐ray diffraction analysis reveals that MOC‐Rh‐1 shows a lantern‐
type cage structure, in which a pair of Rh2(CO2)4 paddlewheels are linked by four diacid ligands. The dimensions of the
inner cavity of MOC‐Rh‐1 are 9.514.8 Å2 (atom‐to‐atom distances across opposite metal and phenyl groups of pbeddb2‐).
In the solid phase, the cages are aligned by π‐π stacking to form one‐dimensional channels (9.5 × 11.1 Å2) through cage
windows. Therefore, the crystalline samples of MOC‐Rh‐1 are porous with the inner and outer cavities of the cages
accessible in the heterogeneous condition. MOC‐Rh‐1 has been fully characterized by EA, TGA, PXRD, IR, UV‐vis and XPS
measurements. The catalytic tests disclose that activated MOC‐Rh‐1 is effective in the intramolecular C‐H amination of
vinyl, dienyl and biaryl azides, leading to the formation of indoles, pyrroles and carbazoles, respectively, and the porous
catalyst can be recycled easily and used for at least nine runs without significant loss of activity. In the nine runs, the
conversions were in the range of 93‐99%, whereas in the tenth run, the conversion was reduced to 78%.
DOI: 10.1039/x0xx00000x
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reported a variety of porous octahedra and cuboctahedra
constructed from Cu2(CO2)4 paddle‐wheel building units.19
Zhou et al. developed a series of MOCs derived from dimetal
paddlewheel unis (Cu2, Mo2, and Ru2 units) and dipotic
carboxylate ligands with bridging angles of 0, 60, 90 and
120°.20‐22
1. INTRODUCTION
Metal‐organic cages (MOCs) have attracted significant
research interests in the past two decades,1 due to their
applications in storage of reactive species,2 drug delivery,3
selective recognition or separation of species from a mix‐
ture,4,5 catalysis,6‐10 etc. Most of the reported MOCs were
constructed from single metal ions and neutral organic
bridging ligands. The assembly of molecular architectures with
metal clusters acting as nodes has not been widely explored.
As a metal cluster node, the dinuclear paddle‐wheel unit has
emerged as a common four‐connected building block in the
synthesis of MOCs.11‐22 The introduction of metal‐metal
bonded clusters into molecular assemblies has not only
expanded the field but also added electrochemical and
Recently, porous materials based on MOCs have been
achieved and exhibited pre‐designed pore properties.1a For
example, the paddlewheel metal units used to form MOCs are
widely employed in the syntheses of metal‐organic
frameworks (MOFs) with infinite channels. Through rational
ligand design, novel porous MOF materials based on MOCs can
be prepared.23 Additionally, the crystal stacking of discrete
MOCs in a proper packing mode, infinite channels through
cage windows can be formed.15b,21b When these MOCs are
used as solid materials, they can be considered porous
materials, and therefore exhibit pore properties such as gas
adsorption. More importantly, such heterogeneous MOC
catalysts can promote both of the in‐cage and out‐cage
reactions with high efficiency, considering that the active
metal sites located in both of inner and outer surfaces can be
accessed other than the polymer‐supported catalysts with
catalytically active sites on the exteriors alone.
Despite the availability of many MOCs containing dimetal
units, only a limited number of them have been further
applied in catalysis.24 Whelan and coworker have utilized
molecular loops (Mo2)2L2 as catalysts for the polymerization of
norbornene.24a Zhou et al.24b and us24c have prepared lantern‐
type polyhedral (Cu2)2L4, which were then applied in
cyclopropanation reactions. Dastidar et al. have reported a
spectroscopic probes to the study of such clusters.11 Cotton
4+
and Murillo have employed dimetal units, especially Mo2
,
4+
Rh2 and Ru25+, in the construction of polygons such as
molecular loops, triangles and squares, as well as polyhedra
such as tetrahedron and octahedron.16‐18 Yaghi and co‐workers
a. MOE Laboratory of Bioinorganic and Synthetic Chemistry, Lehn Institute of
Functional Materials, School of Chemistry and Chemical Engineering, Sun Yat‐sen
University, Guangzhou 510275, China. E‐mail: zhli99@mail.sysu.edu.cn;
cesscy@mail.sysu.edu.cn
b. State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic
Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
† Electronic Supplementary Information (ESI) available: Syntheses of ligand and
azides, heterogeneous catalysis and recyclability, NMR spectra of pure products of
indoles, pyrroles and carbazoles, TOF‐MS spectra, single‐crystal and powder X‐ray
diffraction (PXRD) analyses, XPS spectra. CIF files giving crystallographic data. See
DOI: 10.1039/x0xx00000x
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collected with a Nicolet/Nexus‐670 FT‐IR spectrometer in the
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‐1
DOI: 10.1039/C5TA05592J
region of 4000‐400 cm . UV‐vis spectra were tested on a
Shimadzu/UV‐3600 spectrophotometer. H NMR spectra were
1
recorded on Varian/Mercury‐Plus 300MHz or on Bruker
AVANCE III 400MHz. Chemical shifts were quoted in parts per
million (ppm) referenced to the appropriate solvent peak or 0
ppm for TMS. PXRD patterns were recorded on SmartLab X‐ray
powder diffractometer (Rigaku Co.) at 40 kV and 30 mA with a
Cu target tube. Thermogravimetric (TG) analyses were

performed under an N2 atmosphere at a heating rate of 10 C
min‐1 by using a NETZSCH TG 209 system. X‐ray photoelectron
spectroscopy (XPS) was performed on a ULVAC PHI Quantera
microprobe. Binding energies (BE) were calibrated by setting
the measured BE of C 1s to 284.65 eV. ICP spectroscopy was
conducted on a Spectro Ciros Vision ICP‐OES spectrometer
that is equipped with vacuum optics covering the spectral
range from 175‐777 nm, plasma power, 1300 w; coolant flow,
15.00 L/min; auxiliary flow, 0.80 L/min; nebulizer 0.70 L/min.
The sorption isotherms for N2 (77 K) and CO2 (195 K) gas were
measured with an Autosorb‐iQ2‐MP gas sorption analyzer
(Quantachrome, USA). The samples are vacuumed at 110 °C for
6 h before the sorption examination.
=
Scheme 1. MOC Synthesis.
truncated octahedron (Cu2)6L8 and examined its catalytic
activity in the oxidation of benzyl alcohol to benzaldehyde.24d
Cotton and Murillo have developed molecular triangles
(Rh2)3L3 and used them in asymmetric cyclopropanation.24
Meanwhile, dirhodium complexes are commonly used
catalyst due to their diverse catalytic reactivity, especially in
nitrene transfer reactions.25 The activation of C‐H bonds by
dirhodium(II) nitrenoids allows access to valuable carbocycles
and hetereocycles efficiently. Since azides are readily available
and the only byproduct is N2, the prospect of rhodium
nitrenoid generation from them is highly appealing. Driver
recently discovered that rhodium(II) carboxylates can catalyze
the intramolecular formation of C‐N bonds from vinyl, dienyl
and biaryl azides to provide indoles, pyrroles and carbazoles,
respectively.26
Cautions! Although we have not experienced any problem
in the handling of the azides (e.g. vinyl azides, dienyl azides
and biaryl azides), extreme care should be taken when
manipulating them due to their explosive nature.
2.2 Synthesis of [Rh4(pbeddb)4(H2O)2(DMAC)2] (MOC‐Rh‐1)
H2pbeddb (18.3 mg, 0.05 mmol), Rh2(OAc)4 (8.8 mg, 0.02
mmol), Na2CO3 (6.0 mg 0.057 mmol) and dimethylacetamide
(DMAC, 4 mL) were placed in a glass vial, which was then
sealed and heated to 100 °C in an oven. After 24 h, green block
crystals were obtained (11.2 mg, 54% yield based on
Rh2(OAc)4). Anal. Calcd. for C124H127N7O31Rh4 (MOC‐Rh‐
To the best of our knowledge, there were two reports of
MOCs based on dirhodium(II) paddlewheel units, but none of
them have been tested in nitrene transfer reactions.17b,c In this
work, a lantern‐type MOC of [Rh4(pbeddb)4(H2O)2(DMAC)2]
16H2O5DMAC): C, 56.78; H, 4.88, N, 3.74%; Found: C, 56.55;
H, 4.98; N, 3.85%. FTIR (KBr) ν 3431 (s, br), 2919 (w), 1625 (m),
1606 (w), 1462 (w), 1425(w), 1387 (m), 1343 (w), 1082 (m. br),
784 (w) cm‐1.
(MOC‐Rh‐1
) (pbeddb2‐ = 3,3'‐(1,3‐phenylenebis(ethyne‐2,1‐
2.3 X‐ray Crystallography
diyl))dibenzoate)) has been synthesized from the self‐assembly
of Rh2(OAc)4 and the rigid diacid H2pbeddb (Scheme 1), which
was then employed in C‐H amination reactions with azides.
The X‐ray diffraction data were collected with an Agilent
Technologies SuperNova X‐RAY diffractometer system for
MOC‐Rh‐1 equipped with Cuk radiation ( = 1.54178 Å). The

crystal was kept at 150.00(10) K during data collection. Using
Olex228, the structure was solved with the ShelXS‐9729
structure solution program using Direct Methods and refined
with the XL30 refinement package using Least Squares
minimization. The positions of the hydrogen atoms were
generated geometrically. A summary of the crystal structure
refinement data and selected bond angles and distances are
listed in Table 1 and Table S1. Crystallographic data for the
structure have been deposited in the Cambridge
Crystallographic Data Center with CCDC reference number
1057865.
2. EXPERIMENTAL SECTION
2.1 General
All the reagents in the present work were obtained from the
commercial source and used directly without further
purification. The ligand 3,3'‐[1,3‐phenylenebis(ethyne‐2,1‐
diyl)]dibenzoic acid (H2pbeddb) was synthesized according to
the literature.21b Vinyl azides, dienyl azides and biaryl azides
are prepared following the reported precedures.27 The
elemental analyses were performed with Perkin‐Elmer 240
elemental analyzer. HRESI‐MS was performed by using a
Bruker Daltonics ESI‐Q‐TOF maXis4G. The data analyses of ESI‐
TOF mass spectra were processed on Bruker Data Analysis sof‐
tware and the simulations were performed on Bruker Isotope
Pattern software. Infrared spectra on KBr pellets were
2.4 Typical Procedure for the Catalytic C‐H Bond Amination
Reactions
Toluene (0.75 mL) was added to the mixture of (Z)‐methyl 2‐
azido‐3‐phenylacrylate (2a, 30.4 mg, 0.15 mmol) and activated
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reduce the total volume to about 0.5 mL. AfVteierwwAratircdle,Ontlhinee
reaction mixture was added with nitric acid (6 mL) and
Table 1. Crystal data and structure refinement parameters
MOC‐Rh‐ 2H2O 3DMAC
DOI: 10.1039/C5TA05592J
1


aqueous hydrogen dioxide (30 wt%, 1 mL), stayed at room
temperature for 3 h, and then concentrated to 0.5 mL. The
digestion procedure was repeated twice. The resulted
colourless solution was diluted volumetrically with an aqueous
solution of nitric acid (2%) to 10 mL, which was then evaluated
by inductively coupled plasma optical emission spectrometer
(ICP‐OES) for Rh contents. The Rh contents were measured in
ppm based on calibration curves obtained with a series of
calibration standard solutions doped with different amount of
Rh. The measured Rh content was 2.037 ppm (0.02037 mg),
and the leached Rh% should be 0.8%, using the calculation
Formula
C121H110N7O28Rh4
2521.80
Fw
T/K
150
Crystal system
triclinic
Space group
P‐1
a/Å
14.3649(9)
15.5751(10)
16.3871(12)
72.966(7)
73.450(6)
68.665(6)
3199.2(4)
1
b/Å
c/Å
α/°
equation “100%
 (0.02037 mg / 2.460 mg)”.
β/°
2.7 Hot Filtration Experiment
γ/°
Volume/Å3
Two parallel C‐H amination reactions of 2a (60.0 mg, 0.30
mmol) in the presence of 2 mol% of activated MOC‐Rh‐1 (12.0
mg) were heated in toluene (1.5 mL) at 60°C. After 6 h, a group
of reaction mixture was filtrated with filtration membrane
(0.45 μm), and the filtrate was allowed to stand at 60°C for
another 10 h. The other group of reaction mixture stayed with
catalyst for further reaction without any treatment. The
conversions of the reactions were monitored by 1H NMR.
Z
ρ
calcg/cm3
1.309
μ/mm‐1
4.685
F(000)
1289.0
Total/Unique
Rint
20800 / 10596
0.0417
Goodness‐of‐fit on F2
R1, wR2 [I>=2σ (I)]
R1, wR2 [all data]
1.036
3. RESULTS AND DISCUSSION
3.1 Design of MOC Catalysts with Rh‐Rh Bonds
0.0591, 0.1697
0.0905, 0.1986
Tetracarboxylate Rh dimers, while are stable to many
conditions, including strong acid, participate freely in ligand
exchange reactions. It was hypothesized that carboxylate
detachment from the dinuclear Rh core was responsible for
catalyst degradation. To prevent the ligands from dissociating
from the metal centers, bridged dirhodium complexes, which
were based on bridging diacid ligands, have been developed.31
The well‐designed bridged dirhodium carboxylates have been
widely used in carbene and nitrene transfer reactions,
exhibiting superior performances in terms of turnover number
and reaction efficiency. We are interested in an alternative
strategy for improving the kinetic stability of dirhodium(II)
complexes through connecting two and more dimetal untis
(Rh24+) with dicarboxylates to form higher order structures
such as polyhedra.17b Taking account of more interactions
existing in these polyhedra, we hypothesize that they were
less prone to ligand exchange than other simple
tetracarboxylate systems (e.g. Rh2(OAc)4) derived from
MOC‐Rh‐1 (6.0 mg, 0.003 mmol, 2 mol%), then the whole
suspension was heated to 60°C for 16h before cooled to room
temperature. The catalyst was removed through
centrifugation, and washed with ethyl acetate (5 mL × 2). The
combined supernatant was evaporated to dryness. The
1
conversion of the reaction was monitored by H NMR (400
MHz) spectroscopy. After that, the reaction mixture was
separated by flash chromatography (1:20 EtOAc: hexanes) to
obtain pure product methyl 1H‐indole‐2‐carboxylate (3a) as
white solid (24.7 mg, 94%).
2.5 Procedure for Recycling Study
A mixture of 2a (101.5 mg, 0.50 mmol) and activated MOC‐Rh‐
1
(40.0 mg, 4 mol%) in toluene (2.5 mL) was heated at 85°C for
8 h. The catalyst was separated by centrifugation, washed with
ethyl acetate (5 mL × 3), dried under vacuum at 110 °C for 6 h
and reused in the consecutive run. The conversion of the
reaction was monitored by 1H NMR spectroscopy.
2.6 ICP Spectrometric Evaluation
monocarboxylic
acids.
The
ligand
3,3'‐[1,3‐
phenylenebis(ethyne‐2,1‐diyl)]dibenzoic acid (H2pbeddb) was
chosen for our MOC catalyst design. As shown in Scheme 1,
A mixture of 2a (60.9 mg, 0.30 mmol) and activated MOC‐Rh‐
1
the anion pbeddb2‐ has a bridging angle of 0
 and a long
(12.0 mg, 2 mol%; containing ca 2.460 mg of Rh) in toluene
(1.5 mL) was heated at 60°C for 16 h. After cooled to room
temperature, the reaction mixture was passed through a sand
core funnel (G5) with a pad of celite, and washed with ethyl
acetate (5 mL × 3). The combined solvent was treated with
nitric acid (2 mL) and hydrochloric acid (6 mL) after
concentrated to about 0.5 mL. The whole mixture was allowed
bridging spacer spanning 11.3 Å, and is useful for the
construction of large porous MOCs. Zhou et. al. and Lah et al.
have previously prepared MOCs, derived from dimetal
paddlewheel units (Mo2 and Cu2 units) and H2pbeddb.15b,21b
The crystal structures of the lantern‐type MOCs of
Mo4(pbeddb)4(S)x (S represents for solvents) and
°
to stay at room temperature for 3 h and heated at 150 C to
Cu4(pbeddb)4(S)x possess internal cavities of 9.7
 15.4 and
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wheel moieties. Each paddle‐wheel moietyViewisArticfluerOtnhliener
coordinated with two molecules in the axDiaOlIp: 1o0s.i1t0io39n/sC,5eTiAt0h5e5r9o2Jf
H2O for the inner Rh(II) atom or DMAC for the exterior Rh(II)
atom. As a result, the axial coordinated solvents might be
removed, leaving both the inner and the outer Rh(II) metal
sites for catalysis. The Rh‐Rh distance in each dirhodium
moieties is 2.39 Å, which is in accordance with the reported
values for the Rh–Rh bond length in Rh‐carboxylate complexes,
and this bond length is generally in the range of 2.34‐2.41 Å.11
The dimensions of the cage excluding coordinated solvents are
approximately 1.4 nm in height (Rh…Rh) and 2.0 nm in
diameter (Ph…Ph between two opposite ligands). The window
of the cage formed by two pbeddb2‐ ligands is about 9.6 Å high,
11.1 Å wide for the larger ones and 10.0 Å for the smaller ones
(Figure S1). The dimensions of the inner cavity of the MOC are
Figure 1. Ball and stick diagram of MOC‐Rh‐1. The insert
picture is the photograph of the single crystals. The bright
green polygon only serves to guide visualization, not to
represent the actual size of the cavity. Rh (Sea green), O (red),
C (gray). All hydrogen atoms and solvent molecules including
those coordinated to Rh‐Rh units are omitted for clarity.
9.5

14.8 Å2 (atom‐to‐atom distances across opposite metal
and phenyl groups of pbeddb2‐).
Three different types of inter‐cage
‐ stacking interactions
between the phenyl groups of the ligands have been observed
(Figure S2 and Table S2). The interactions lead to honeycomb
shape solvent‐filled channels (9.5 × 11.1 Å2) with an overall
49.4% solvent‐accessible volume calculated using the
PLATON32 (Figure 2). One interesting feature of these channels
is that they pass through the windows of the discrete cages. As
a result, both of inner‐cage and outer‐cage metal sites of the
dirhodium metal units in its desolvated form can be accessible
to the incoming guests.
9.0

14.8 Å2 (atom‐to‐atom distances across opposite metal
and phenyl groups of pbeddb2‐), respectively. The crystal
packing patterns of these MOCs are also interesting. Both of
Mo4(pbeddb)4 and Cu4(pbeddb)4 are crystallized in P‐1, and
the inter‐cage
‐ stacking interactions lead to infinite
channels with the dimensions of 9.7 × 10.7 and 9.0 × 11.1 Å2,
respectively. The structure rationale of the above MOCs
assembled from pbeddb2‐ and dimetal units suggested that the
metal centers located in both of inner and outer surfaces were
accessible to the substrates, which might highly increase the
reaction efficiency. We herein desire to develop MOCs with
Rh‐Rh bonds derived from H2pbeddb, which have not been
reported previously.
Control experiments revealed that the alkali Na2CO3 was
essential for the syntheses of crystals suitable for single‐crystal
X‐ray diffraction. Excess (larger than 1.5 eq. relative to the
ligand H2pbeddb) caused precipitation, however. We also
found that the solvents play an important role. When a mixed
solvent of dimethylformamide (DMF) and H2O (v/v=4/1) was
in used instead of DMAC, purple crystals were obtained. Single
3.2 Synthesis and Crystal Structure
The
reaction
of
H2pbeddb
with
Rh2(OAc)4
dimethylacetamide (DMAC) in the presence of Na2CO3 gave crystal structure analysis disclosed that the structure was
rise to green block crystals of [Rh4(pbeddb)4(H2O)2(DMAC)2] almost the same with MOC‐Rh‐ except for the solvents
2H2O 3DMAC (MOC‐Rh‐ 2H2O 3DMAC) (Figure 1). Single‐ coordinated to the outer Rh(II) atoms. Unfortunately, we can
crystal X‐ray diffraction analysis revealed that it crystallizes in not determine the axial solvents based on its single X‐ray
the triclinic centro symmetric space group P‐1. MOC‐Rh‐ is crystal data. We speculate that they were nitrogen‐containing
1


1

1
composed of discrete lantern‐type cages, and each cage
contains four dicarboxylic ligands and two Rh2(COO)4 paddle‐
Figure 2. Solid‐packing of MOC‐Rh‐
1 in the crystal lattice. Left: 1D channels formed through cage windows; Middle and right: the
accessible voids viewed from different directions. Solvent molecules are omitted for clarity. Rh (sea green), O (red), C (gray).
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molecules, which might come from the decomposition of DMF.
On the basis of the study of Johnson et al. and Jessop et al. on
the coordination effects of solvents, dirhodium(II) complexes
with oxygen‐containing solvents (e.g. H2O, THF) in the axial
position were usually in green, whereas those with nitrogen‐
containing solvents (e.g. DMF, MeCN, NEt3) were often in
purple.33
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DOI: 10.1039/C5TA05592J
3.3 Physical Characterizations
To investigate the phase purity of bulk sample, MOC‐Rh‐1 was
subjected to powder X‐ray diffraction (PXRD) test. In air, the
crystals are apt to effloresce probably due to the escape of
lattice solvents. When measured in a sealed capillary tube with
the solvent, the PXRD patterns show comparable diffraction
profile with the simulated one based on the single crystal
(Figure S3), while some peaks are slightly shifted probably
owing to the exchange of solvent molecules.
Figure 4. Solid UV‐vis spectra of as‐synthesized and activated
sample of MOC‐Rh‐1.
of the higher energy band (453 nm) is uncertain, although it
has been attributed to a π*(Rh‐O)→σ*(Rh‐O) transition.35 The
lower energy band is assigned to the HOMO‐LUMO
(π*(Rh2)→σ*(Rh2)) transition, which is strongly affected by the
axial solvents.36 The max for the lower energy peak shifts to
longer wavelengths by only 8 nm (Table S3) after the as‐
Thermogravimetric analysis (TGA) of the as‐synthesized
MOC‐Rh‐1 sample showed a total weight loss of 28.6% in the
range of 30‐210 °C, corresponding to the escape of lattice and
coordinated solvent molecules (expected 28.7%, Figure 3).
Above 350 °C, an abrupt weight loss appears, indicative of the
decomposition of the cages. To examine whether the solvents
could be removed prior to further applications such as gas
adsorption and catalysis, the as‐synthesized sample of MOC‐

synthesized sample was activated under vacuum at 110 C for
6 h. On the basis of the data, we speculated that most of the
coordinated solvents remained on the metal sites under our
activation process. Nevertheless, activated MOC‐Rh‐1 could be
used for catalysis, considering that the coming substrates
could replace these coordinated solvents due to larger affinity
between the former and the Rh(II) metal sites.
To evaluate the porosity and storage capability of MOC‐Rh‐1,
the adsorption isotherms of N2 at 77 K as well as CO2 at 195 K
have been studied (Figure 5). Before the measurements, the
Rh‐
6 h. As shown in the TG curve of activated MOC‐Rh‐
of weight loss occurred below 350 C, suggesting that most of
the solvents have been removed.
1
has been activated by heating at 110 °C under vacuum for
, only 6.3%
1
°
The infrared spectrum of MOC‐Rh‐1 is similar to that of
reported dirhodium(II) tetracarboxylates.33a The asymmetric
stretching vibrations (νas(COO)) and symmetric stretching
vibrations (νs(COO)) of the coordinate carboxylate groups are
observed at 1625 and 1462 cm‐1, respectively. The splitting Δ
value of 163 between these two bands (ΔCOO= νas (COO) ‐ νs
(COO)) might indicate the carboxylate groups in bridging
bidentade coordination mode,34 which is in consistent with the
single‐crystal X‐ray diffraction analyses.
bulk samples of MOC‐Rh‐
110 °C under vacuum for 6 h. The N2 sorption isotherm of
activated MOC‐Rh‐ at 77K does not show any appreciable
1 were activated through heating at
1
amount of adsorption. However, at 195 K and 1 atm, the
uptake of CO2 is 33.9 cm2g‐1, corresponding to about 3 CO2
molecules adsorbed per MOC‐Rh‐
CO2 adsorption isotherm a 195 K, the BET surface area of
MOC‐Rh‐
is calculated to be about 95 m2g‐1. The selective gas
1 molecule. Based on the
1
adsorption for CO2 over N2 have been observed in other
lantern‐type MOCs such as activated Cu4(pbeddb)4(S)x and
Cu4(nddb)4(S)x (H2nddb = 3,3’‐(naphthalene‐2,7‐diyl)dibenzoic
acid).15b,23b
The solid UV‐vis spectrum of the as‐synthesized MOC‐Rh‐
1
sample was shown in Figure 4, which displayed two principal
bands at 453 and 587 nm. These two bands are characteristic
of the dirhodium paddle‐wheel structure, which is absent in
the absorption spectrum of the organic ligand. The assignment
Figure 5. Gas adsorption/desorption isotherms of N2 (77K) and
Figure 3. The TG curves of as‐synthesized and activated MOC‐
Rh‐1.
CO2 (195K) of activated MOC‐Rh‐
open symbols, desorption.
1. Solid symbols, adsorption;
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Journal Name
3.4 Catalytic Performances
Table 2. Substrate Scope of Catalytic C‐H Aminationa
View Article Online
DOI: 10.1039/C5TA05592J
C‐H amination in the homogeneous phase has been greatly
enhanced due to improved methods of the synthesis of
rhodium nitrene intermediates.25 MOC‐Rh‐
1 isn’t dissolved in
common organic solvents, such as toluene, DMSO, DMF, H2O,
acetone and acetonitrile, which indicates that it might act as a
heterogeneous catalyst. It is noted that MOC‐Rh‐
large inner and outer cavities, whose sizes are 9.5
and 9.5
11.1 Å2, respectively, suggesting that the catalytic
reactions might occur both on the internal and external
surfaces of the crystal catalysts.
1
possesses

entry
1
product
entry
product
91%
14.8 Å2

2
The evaluation of the heterogeneous catalytic capabilities of
activated MOC‐Rh‐1 was carried out using C‐H amination of
94%
vinyl azides. The homogeneous protocol has been successfully
elaborated by Driver et al. and has transformed vinyl azides
(e.g. (Z)‐methyl 2‐azido‐3‐arylacrylate) into indoles in high
yields, using rhodium(II) perfluorobutyrate (Rh2(O2CC3F7)4) as
the catalyst.26a As can be seen in Table 2, the reaction of (Z)‐
methyl 2‐azido‐3‐phenylacrylate (2a) as well as (Z)‐methyl 2‐
azido‐3‐(4‐methoxyphenyl)acrylate (2b) in the presence of 2
3
5
4
6
64% (90%b)
44% (62%c)
32% (86%d)
54% (92%d)
28% (78%d)
mol% of activated MOC‐Rh‐1 was accomplished with larger

than 99% conversion after 16 h at 60 C, leading to the
formation of the indoles 3a and 3b in 94% and 91% yield,
respectively (entries 1 and 2). By contrast, the yields for (Z)‐
methyl 2‐azido‐3‐(p‐tolyl)acrylate (2c) and (Z)‐methyl 2‐azido‐
3‐(1,1’‐biphenyl)acrylate (2d) were reduced to 64% and 44%,
7
8
88%

respectively, under the same reaction conditions at 60 C
(entries 3 and 4). Increasing the reaction temperature to 85 C
could significantly improve the yields with up to 90% for 3c
and 62% for 3d in 3 h and 24 h, respectively. Halogen
substituted azides 2e‐g showed much poorer performances,
and the corresponding indoles 3e‐g were obtained in less than
9
10
98%e
92%f
a

Reaction conditions: 2 mol% of the catalyst, 60 C, 16 h,
toluene. The yields are isolated yields. b85 C, 3 h. c85 C, 24

60% yields when the catalytic reactions were heated at 60 C
for 16 h (entries 5‐7). Similarly, 3e‐g can be prepared in much
d
e
f


h. 85 C, 5 h. 0.5 mol% of the catalyst load, 85 C, 2 h. 3
mol% of the catalyst load, DME, 85 C, 16 h.
higher yields at a higher temperature, and the isolated yields

were 92%, 86% and 78%, respectively, at 85 C in 5 h. In
formation of rhodium nitrenoid and the C‐N bond formation
addition to indoles, aromatic N‐heterocycles such as 3h can be
accessed from 1‐substituted naphthalene vinyl azide (entry 8).
Driver et al. have also showed that pyrroles and carbazoles
could be produced from the similar intramolecular C‐H
amination of dienyl azides and biaryl azides, respectively.26b,d
On the basis of their homogeneous protocols, we further
occurs through a 4
‐electron‐5‐atom electrocyclization.26l In
this mechanism, 3‐methoxy group in (Z)‐methyl 2‐azido‐3‐(3‐
methoxyphenyl)acrylate (2i) acts as an inductive electron‐
withdrawing group and slows down the formation of rhodium
nitrenoid. We have examined the reaction of 3‐methoxy
substituted azide 2i in the presence of 2 mol% MOC‐Rh‐1 and
heating at 60 C for 16 h. The reaction was very messy, and a
1:1 mixture of 5‐ and 7‐regioisomers was obtained in less than
30% yield. The data indicate that the MOC‐Rh‐
bond formation reaction occurs through a similar 4
5‐atom electrocyclization as the Driver’s protocol.
To verify the reactions were heterogeneous but not
catalyzed by dissociated Rh species that were leached into the
reaction solutions, we carried out a hot filtration experiment
(Figure 6). At the 26% conversion of intramolecular the C‐H
amination reaction of 2a in the presence of activated MOC‐Rh‐
tested the catalytic capability of activated MOC‐Rh‐
syntheses of pyrroles and carbazoles. Methyl 5‐phenyl‐1H‐
pyrrole‐2‐carboxylate ( ) and 9H‐carbazole ( ) can be obtained
in high yields under optimized reaction conditions in the
presence of activated MOC‐Rh‐ (entries 9 and 10). We have
1 in the

4
5
1
catalyzed C‐N
‐electron‐

1
also tested the catalytic activity of the Cu4(pbeddb)4, Rh2(OAc)4
and RhCl3 in the C‐H intramolecular amination of 2a (Table S4).
No reaction occurs in the presence of Cu4(pbeddb)4 or RhCl3.
The conversion in the presence of Rh2(OAc)4 is 11%. Our MOC
catalyst, MOC‐Rh‐1, shows obvious advantages over them.
In Rh2(O2CC3F7)4‐catalyzed intramolecular C‐H amination of
azides, it is proposed that the reaction proceeds through the
rhodium nitrenoid intermediate, the electronic donation by
the 4‐substituted group (e.g. 4‐OMe) accelerates the
1
for 6 h, the reaction mixture was filtrated with filtration
membrane (0.45 μm), and the filtrate was allowed to stand for
another 10 h. The conversion of the supernatant rose to 36%
6 | J. Name., 2012, 00, 1‐3
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ARTICLE
peaks at 313.9 and 309.2 eV assigned to Rh 3d3/2 and Rh 3d5/2
,
View Article Online
DOI: 10.1039/C5TA05592J
indicative of the +2 valence nature of Rh. According to the
literatures, the 3d5/2 binding energy of oxidized Rh2+ is in the
range of 308.4 and 309.3 eV.37
4. CONCLUSION
A reproducible synthesis of a lantern‐type metal‐organic cage
(MOC‐Rh‐1) consisting of two dirhodium units joined by four
ditopic dicarboxylic ligands has been established. The well‐
designed MOC catalyst possesses more active Rh(II) sites than
the general polymer‐supported heterogeneous Rh(II)
complexes with the active metal sites on the external surfaces
alone. Depending on the crystal structures, the MOC possesses
large windows (9.6 × 11.1 Å2), and provide a platform to carry
out reactions in its cavities. Additionally, the large channels
(9.5 × 11.1 Å2) formed by the crystal stacking of discrete MOCs
make it possible that the catalytic reactions occur within the
channels. Catalytic tests show that it can efficiently promote
the intramolecular C‐H amination of azides, and the catalyst
can be recycled easily and used for at least nine runs without
significant loss of activity. These catalytic results are quite
encouraging and we are currently pursuing the design and
synthesis of more MOC catalysts with Rh‐Rh bonds.
Figure 6. Filtration experiment for activated MOC‐Rh‐
Conversions are given as a function of time. The full square (
represents the reaction with MOC‐Rh‐
cycle (●) represents the reacꢀon aꢁer removal of catalyst
MOC‐Rh‐ at (26%) conversion.
1
.
■)
1
as a catalyst. The full
1
with 10% increase. In contrast, control experiments show that
a parallel reaction with the catalyst reached around 100%
conversion after the same reaction time. Based on the
filtration experiment, we believe that the reaction is basically
heterogeneous, and we ascribe the additional 10% conversion
to the leached Rh during the reaction. Inductively coupled
plasma optical emission spectrometer analysis of the reaction
filtrate indicated that the amount of the rhodium leaching into
the reaction mixture was 0.8% of the total Rh content in MOC‐
ACKNOWLEDGMENT
This work was supported by the 973 Program (2012CB821701)
and the NSFC Projects (21373278, 21102186, 91222201,
21173272, 21450110063), the NSF of Guangdong Province
(S2013030013474) and the RFDP of Higher Education of China
(20120171130006).
Rh‐1.
One remarkable feature of this C‐H amination catalysis is
that the MOC catalyst can be easily isolated by centrifugation
and can be reused at least nine times without significant loss
of activity (Figure 7, Table S4). In the nine runs, the
conversions of 2a were in the range of 93‐99%, whereas in the
tenth run, the conversion was reduced to 78%. To verify the
valence states of the Rh in the recycled catalyst, X‐ray
photoelectron spectroscopy (XPS) has been carried out. As
shown in Figure S4, the XPS spectrum displayed two intense
Notes and references
1
(a) T. R. Cook, Y.‐R. Zheng and P. J. Stang, Chem. Rev., 2013,
113, 734‐777. (b) M. M. J. Smulders, I. A. Riddell, C. Browne
and J. R. Nitschke, Chem. Soc. Rev., 2013, 42, 1728‐1754. (c)
H. Amouri, C. Desmarets and J. Moussa, Chem. Rev., 2012,
112, 2015‐2041. (d) M. Yoshizawa, J. K. Klosterman and M.
Fujita, Angew. Chem., Int. Ed., 2009, 48, 3418‐3438. (e) C. G.
Oliveri, P. A. Ulmann, M. J. Wiester and C. A. Mirkin, Acc.
Chem. Res., 2008, 41, 1618‐1629. (f) D. Fiedler, D. H. Leung,
R. G. Bergman and K. N. Raymond, Acc. Chem. Res., 2005, 38
,
351‐360. (g) J. Liu, L. Chen, H. Cui, J. Zhang, L. Zhang and C.‐Y.
Su, Chem. Soc. Rev., 2014, 43, 6011‐6061.
2
(a) J. W. Leeland, F. J. White and J. B. Love, J. Am. Chem. Soc.,
2011, 133, 7320‐7323. (b) P. Mal, B. Breiner, K. Rissanen and
J. R. Nitschke, Science, 2009, 324, 1697‐1699. (c) K. Li, L. Y.
Zhang, C. Yan, S. C. Wei, M. Pan, L. Zhang and C. Y. Su, J. Am.
Chem. Soc., 2014, 136, 4456‐4459.
3
4
J. E. M. Lewis, E. L. Gavey, S. A. Cameron and J. D. Crowley,
Chem. Sci., 2012, 3, 778‐784.
(a) S. Tashiro and M. Fujita, Bull. Chem. Soc. Jpn., 2006, 79
833‐837. (b) Y. R. Hristova, M. M. J. Smulders, J. K. Clegg, B.
Breiner and J. R. Nitschke, Chem. Sci., 2011, , 638‐641. (c) S.
,
2
Turega, M. Whitehead, B. R. Hall, M. F. Haddow, C. A. Hunter
and M. D. Ward, Chem. Commun., 2012, 48, 2752‐2754.
(a) T. F. Liu, Y. Liu, W. M. Xuan and Y. Cui, Angew. Chem., Int.
Ed., 2010, 49, 4121‐4124. (b) W. M. Xuan, M. N. Zhang, Y. Liu,
5
Figure 7. Recycling experiments.
This journal is © The Royal Society of Chemistry 20xx
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Please do not adjust margins
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Page 8 of 9
ARTICLE
Z. J. Chen and Y. Cui, J. Am. Chem. Soc., 2012, 134, 6904‐
Journal Name
Am. Chem. Soc., 2005, 127, 12752‐12753. (c) H. Furukawa, J.
Kim, K. E. Plass and O. M. Yaghi, J. Am.DCOhIe: m10..1S0o3Vci9e./w,C2A5r0TtiA0cl06e5,O51n9l2i2n8Je
8398‐8399. (d) H. Furukawa, J. Kim, N. W. Ockwig, M.
6907. (c) J. Dong, Y. Zhou, F. Zhang and Y. Cui, Chem. Eur. J.,
2014, 20, 6455‐6461.
(a) M. Yoshizawa, T. Kusukawa, M. Fujita and K. Yamaguchi, J.
Am. Chem. Soc., 2000, 122, 6311‐6312. (b) M. Yoshizawa, S.
,
6
O'Keeffe and O. M. Yaghi, J. Am. Chem. Soc., 2008, 130
,
11650‐11661.
Miyagi, M. Kawano, K. Ishiguro and M. Fujita, J. Am. Chem. 20 (a) J. R. Li and H. C. Zhou, Angew. Chem., Int. Ed., 2009, 48
,
Soc., 2004, 126, 9172‐9173. (c) Y. Nishioka, T. Yamaguchi, M.
Kawano and M. Fujita, J. Am. Chem. Soc., 2008, 130, 8160‐
8161.
8465‐8468. (b) J. R. Li, D. J. Timmons and H. C. Zhou, J. Am.
Chem. Soc., 2009, 131, 6368‐6369. (c) D. Zhao, D. Q. Yuan, R.
Krishna, J. M. van Baten and H. C. Zhou, Chem. Commun.,
2010, 46, 7352‐7354. (d) J. R. Li and H. C. Zhou, Nat. Chem.,
2010, 2, 893‐898. (e) D. Zhao, S. W. Tan, D. Q. Yuan, W. G. Lu,
Y. H. Rezenom, H. L. Jiang, L. Q. Wang and H. C. Zhou, Adv.
7
(a) M. D. Pluth, R. G. Bergman and K. N. Raymond, Angew.
Chem., Int. Ed., 2007, 46, 8587‐8589. (b) M. D. Pluth, R. G.
Bergman and K. N. Raymond, Science, 2007, 316, 85‐88. (c) C.
J. Brown, R. G. Bergman and K. N. Raymond, J. Am. Chem.
Soc., 2009, 131, 17530‐17531. (d) C. J. Hastings, M. D. Pluth,
R. G. Bergman and K. N. Raymond, J. Am. Chem. Soc., 2010,
132, 6938‐6940. (e) C. J. Brown, G. M. Miller, M. W. Johnson,
R. G. Bergman and K. N. Raymond, J. Am. Chem. Soc., 2011,
133, 11964‐11966. (f) C. Zhao, Q. F. Sun, W. M. Hart‐Cooper,
Mater., 2011, 23, 90‐93. (f) T. F. Liu, Y. P. Chen, A. A.
Yakovenko and H. C. Zhou, J. Am. Chem. Soc., 2012, 134
,
17358‐17361. (g) J. Park, L. B. Sun, Y. P. Chen, Z. Perry and H.
C. Zhou, Angew. Chem., Int. Ed., 2014, 53, 5842‐5846. (h) J.
Park, Y. P. Chen, Z. Perry, J. R. Li and H. C. Zhou, J. Am. Chem.
Soc., 2014, 136, 16895‐16901.
A. G. Dipasquale, F. D. Toste, R. G. Bergman and K. N. 21 (a) Y. X. Ke, D. J. Collins and H. C. Zhou, Inorg. Chem., 2005,
Raymond, J. Am. Chem. Soc., 2013, 135, 18802‐18805.
(a) D. H. Wang, B. G. Zhang, C. He, P. Y. Wu and C. Y. Duan,
Chem. Commun., 2010, 46, 4728‐4730. (b) X. Wu, Z. H. Lin, C.
He and C. Y. Duan, New. J. Chem., 2012, 36, 161‐167. (c) Y. 22 M. D. Young, Q. Zhang and H. C. Zhou, Inorg. Chem. Acta,
Jiao, J. Wang, P. Y. Wu, L. Zhao, C. He, J. Zhang and C. Y. Duan, 2015, 424, 216‐220.
Chem. Eur. J., 2014, 20, 2224‐2231. (d) J. Zhang, H. Yu, C. X. 23 (a) Y. Zou, M. Park, S. Hong and M. S. Lah, Chem. Commun.,
44, 4154‐4156. (b) J. R. Li, A. A. Yakovenko, W. G. Lu, D. J.
Timmons, W. J. Zhuang, D. Q. Yuan and H. C. Zhou, J. Am.
Chem. Soc., 2010, 132, 17599‐17610.
8
9
Zhang, C. He and C. Y. Duan, New. J. Chem., 2014, 38, 3137‐
3145.
2008, 2340‐2342. (b) Z. J. Zhang, W. Shi, Z. Niu, H. H. Li, B.
Zhao, P. Cheng, D. Z. Liao and S. P. Yan, Chem. Commun.,
2011, 47, 6425‐6427. (c) J. R. Li, J. M. Yu, W. G. Lu, L. B. Sun, J.
Sculley, P. B. Balbuena and H. C. Zhou, Nat. Commun., 2013,
J. L. Bolliger, A. M. Belenguer and J. R. Nitschke, Angew.
Chem., Int. Ed., 2013, 52, 7958‐7962.
10 (a) Q. T. He, X. P. Li, L. F. Chen, L. Zhang, W. Wang and C. Y.
4, 1538‐1545.
Su, ACS Catal., 2013, , 1‐9. (b) Y. Huang, Z. Lin and R. Cao, 24 (a) E. Whelan, M. Devereux, M. McCann and V. McKee, Chem.
3
Chem. Eur. J., 2011, 17, 12706‐12712. (c) Y. Huang, T. Ma, P.
Commun., 1997, 427‐428. (b) W. G. Lu, D. Q. Yuan, A.
Yakovenko and H. C. Zhou, Chem. Commun., 2011, 47, 4968‐
4970. (c) L. Chen, J. Kang, H. Cui, Y. Wang, L. Liu, L. Zhang and
C.‐Y. Su, Dalton Trans., 2015, 44, 12180‐12188. (d) M. Paul, N.
Huang, D. Wu, Z. Lin and R. Cao, ChemCatChem, 2013, 5,
1877‐1883.
11 (a) M. H. Chisholm, Coord. Chem. Rev., 2013, 257, 1576‐1583.
(b) F. A. Cotton, C. A. Murillo and R. A. Walton, Multiple
Bonds Between Metal Atoms, Springer Science and Business
Media, Inc. 2005. (c) F. A. Cotton, C. Lin and C. A. Murillo, Acc.
Chem. Res., 2001, 34, 759‐771.
N. Adarsh and P. Dastidar, Cryst. Growth Des., 2014, 14
,
1331‐1337 (e) F. A. Cotton, C. A. Murillo, S. E. Stiriba, X. P.
Wang and R. M. Yu, Inorg. Chem., 2005, 44, 8223‐8233.
25 (a) P. Muller and C. Fruit, Chem. Rev., 2003, 103, 2905‐2919.
(b) G. Dequirez, V. Pons and P. Dauban, Angew. Chem., Int.
Ed., 2012, 51, 7384‐7395. (c) J. L. Roizen, M. E. Harvey and J.
Du Bois, Acc. Chem. Res., 2012, 45, 911‐922.
12 M. J. Byrnes, M. H. Chisholm and N. J. Patmore, Inorg. Chem.,
2005, 44, 9347‐9352.
13 (a) R. P. Bonar‐Law, T. D. McGrath, N. Singh, J. F. Bickley and
A. Steiner, Chem. Commun., 1999, 2457‐2458. (b) R. P. 26 (a) B. J. Stokes, H. J. Dong, B. E. Leslie, A. L. Pumphrey and T.
Bonar‐Law, J. F. Bickley, C. Femoni and A. Steiner, J. Chem.
Soc., Dalton Trans., 2000, 4244‐4246.
G. Driver, J. Am. Chem. Soc., 2007, 129, 7500‐7501. (b) H.
Dong, M. Shen, J. E. Redford, B. J. Stokes, A. L. Pumphrey and
14 B. Moulton, J. J. Lu, A. Mondal and M. J. Zaworotko, Chem.
Commun., 2001, 863‐864.
15 (a) M. J. Prakash, Y. Zou, S. Hong, M. Park, M.‐P. N. Bui, G. H.
Seong and M. S. Lah, Inorg. Chem., 2009, 48, 1281‐1283. (b)
M. J. Prakash, M. Oh, X. Liu, K. N. Han, G. H. Seong and M. S.
Lah, Chem. Commun., 2010, 46, 2049‐2051.
16 (a) F. A. Cotton, L. M. Daniels, C. Lin and C. A. Murillo, Chem.
Commun., 1999, 841‐842. (b) F. A. Cotton, C. Lin and C. A.
Murillo, Inorg. Chem., 2001, 40, 472‐477. (c) F. A. Cotton, C.
Lin and C. A. Murillo, Inorg. Chem., 2001, 40, 478‐484. (d) F.
T. G. Driver, Org. Lett., 2007, 9, 5191‐5194. (c) M. H. Shen, B.
E. Leslie and T. G. Driver, Angew. Chem., Int. Ed., 2008, 47
5056‐5059. (d) B. J. Stokes, B. Jovanovic, H. J. Dong, K. J.
Richert, R. D. Riell and T. G. Driver, J. Org. Chem., 2009, 74
,
,
3225‐3228. (e) K. Sun, S. Liu, P. M. Bec and T. G. Driver,
Angew. Chem., Int. Ed., 2011, 50, 1702‐1706. (f) B. J. Stokes,
S. Liu and T. G. Driver, J. Am. Chem. Soc., 2011, 133, 4702‐
4705. (g) A. L. Pumphrey, H. J. Dong and T. G. Driver, Angew.
Chem., Int. Ed., 2012, 51, 5920‐5923. (h) Q. Nguyen, K. Sun
and T. G. Driver, J. Am. Chem. Soc., 2012, 134, 7262‐7265. (i)
C. Kong, N. Jana and T. G. Driver, Org. Lett., 2013, 15, 824‐
827. (j) C. Jones, Q. Nguyen and T. G. Driver, Angew. Chem.,
Int. Ed., 2014, 53, 785‐788. (k) C. Jones, D. Boudinet, Y. Xia,
M. Denti, A. Das, A. Facchetti and T. G. Driver, Chem. Eur. J.,
2014, 20, 5938‐5945. (l) B. J. Stokes, K. J. Richert and T. G.
Driver, J. Org. Chem., 2009, 74, 6442‐6451.
A. Cotton, C. Lin and C. A. Murillo, Inorg. Chem., 2001, 40
575‐577.
,
17 (a) F. A. Cotton, L. M. Daniels, C. Lin, C. A. Murillo and S. Y. Yu,
J. Chem. Soc., Dalton Trans., 2001, 502‐504. (b) F. A. Cotton,
C. Lin and C. A. Murillo, Inorg. Chem., 2001, 40, 6413‐6417. (c)
F. A. Cotton, C. A. Murillo, X. P. Wang and R. M. Yu, Inorg.
Chem., 2004, 43, 8394‐8403. (d) F. A. Cotton, C. A. Murillo 27 W. G. Shou, J. Li, T. Guo, Z. Lin and G. Jia, Organometallics,
and R. M. Yu, Inorg. Chem., 2005, 44, 8211‐8215. 2009, 28, 6847‐6854.
18 P. Angaridis, J. F. Berry, F. A. Cotton, C. A. Murillo and X. P. 28 O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K. Howard
Wang, J. Am. Chem. Soc., 2003, 125, 10327‐10334. and H. Puschmann, J. Appl. Cryst., 2009, 42, 339‐341.
19 (a) M. Eddaoudi, J. Kim, J. B. Wachter, H. K. Chae, M. 29 G. M. Sheldrick, SHELX 97, Program for Crystal Structure
O'Keeffe and O. M. Yaghi, J. Am. Chem. Soc., 2001, 123 Solution and Refinement, Göttingen University, 1997
4368‐4369. (b) Z. Ni, A. Yassar, T. Antoun and O. M. Yaghi, J. 30 G. M. Sheldrick, Acta Cryst., 2008, A64, 112‐122.
,
8 | J. Name., 2012, 00, 1‐3
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31 (a) Taber, D. F.; Meagley, R. P.; Louey, J. P.; Rheingold, A. L.
View Article Online
DOI: 10.1039/C5TA05592J
Inorg. Chem. Acta, 1995, 239, 25‐28. (b) H. M. L. Davies and C.
Venkataramani, Org. Lett., 2003,
5, 1403‐1406. (c) C. G.
Espino, K. W. Fiori, M. Kim and J. Du Bois, J. Am. Chem. Soc.,
2004, 126, 15378‐15379. (d) J. Du Bois, Chemtracts‐Org.
Chem., 2005, 18, 1‐13. (e) D. N. Zalatan and J. Du Bois, J. Am.
Chem. Soc., 2009, 131, 7558‐7559.
32 A. L. Spek, J. Appl. Crystallogr, 2003, 36, 7‐13.
33 (a) S. A. Johnson, H. R. Hunt and H. M. Neumann, Inorg.
Chem., 1963, 2, 960‐962. (b) D. C. Wynne, M. M. Olmstead
and P. G. Jessop, J. Am. Chem. Soc., 2000, 122, 7638‐7647.
34 a) K. Tan, N. Nijem, P. Canepa, Q. Gong, J. Li, T. Thonhauser
and Y. J. Chabal, Chem. Mater., 2012, 24, 3153‐3167. (b) A.
Doyle, J. Felcman, M. T. D. Gambardella, C. N. Verani and M.
L. B. Tristão, Polyhedron, 2000, 19, 2621‐2627.
35 F. A. Cotton, E. A. Hillard and C. A. Murillo, J. Am. Chem. Soc.,
2002, 124, 5658‐5660.
36 (a) K. M. Kadish, D. Lancon, A. M. Dennis and J. L. Bear, Inorg.
Chem., 1982, 21, 2987‐2992. (b) A. M. Dennis, J. D. Korp, I.
Bernal, R. A. Howard and J. L. Bear, Inorg. Chem., 1983, 22
,
1522‐1529. (c) T. P. Zhu, M. Q. Ahsan, T. Malinski, K. M.
Kadish and J. L. Bear, Inorg. Chem., 1984, 23, 2‐3.
37 (a) M. Q. Ahsan, I. Bernal and J. L. Bear, Inorg. Chem., 1986,
25, 260‐265. (b) J. F. Múnera, S. Irusta, L. M. Cornaglia, E. A.
Lombardo, D. V. Cesar and M. Schmal, J. Catal., 2007, 245
,
25‐34. (c) V. Abdelsayed, D. Shekhawat, J. A. Poston and J.
Spivey, J. Catal. Today, 2013, 207, 65‐73.
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