Metal-Organic Frameworks Stabilize Mono(phosphine)-Metal Complexes for Broad-Scope Catalytic Reactions

Article abstract of DOI:10.1021/jacs.6b06239

Mono(phosphine)-M (M-PR₃; M = Rh and Ir) complexes selectively prepared by postsynthetic metalation of a porous triarylphosphine-based metal-organic framework (MOF) exhibited excellent activity in the hydrosilylation of ketones and alkenes, the hydrogenation of alkenes, and the C-H borylation of arenes. The recyclable and reusable MOF catalysts significantly outperformed their homogeneous counterparts, presumably via stabilizing M-PR₃ intermediates by preventing deleterious disproportionation reactions/ligand exchanges in the catalytic cycles.

Full text of DOI:10.1021/jacs.6b06239

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Communication
Metal-Organic Frameworks Stabilize Mono(phosphine)-
Metal Complexes for Broad-Scope Catalytic Reactions
Takahiro Sawano, Zekai Lin, Dean Boures, Bing An, Cheng Wang, and Wenbin Lin
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.6b06239 • Publication Date (Web): 25 Jul 2016
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MetalꢀOrganic Frameworks Stabilize Mono(phosphine)ꢀMetal
Complexes for BroadꢀScope Catalytic Reactions
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1,2,
Takahiro Sawano, Zekai Lin, Dean Boures, Bing An, Cheng Wang, and Wenbin Lin *
1
th
Department of Chemistry, University of Chicago, 929 E 57 St, Chicago, IL 60637, USA
2
Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid
Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005,
P. R. China
6
and drug delivery. MOFs provide a highly tunable platform for
ABSTRACT: Mono(phosphine)ꢀM (MꢀPR ; M = Rh and Ir)
3
designing singleꢀsite solid catalysts, for example, by incorporating
orthogonal ligands to MOFs. Herein we report the first selective
synthesis of (mono)phosphineꢀM complexes in MOFs (P1ꢀ
complexes selectively prepared by postsynthetic metalation of a
porous triarylphosphineꢀbased metalꢀorganic framework (MOF)
exhibited excellent activity in the hydrosilylation of ketones and
alkenes, the hydrogenation of alkenes, and the CꢀH borylation of
arenes. The recyclable and reusable MOF catalysts significantly
outperformed their homogeneous counterparts, presumably via
7
MOF•M, M = Rh and Ir) by taking advantage of the isolation of
phosphine sites. The resulting P ꢀMOF•M catalysts are highly
active in the hydrosilylation of ketones and alkenes, the hydroꢀ
genation of alkenes, and the CꢀH borylation of arenes.
1
stabilizing MꢀPR intermediates by preventing deleterious disproꢀ
3
portionation reactions/ligand exchanges in the catalytic cycles.
We targeted a new P ꢀMOF (I) with Zrꢀoxo SBUs and triꢀ
1
arylphosphineꢀderived tricarboxylate (L) linkers, due to the stabilꢀ
8
ity of Zrꢀcarboxylate bonds and the coordination incompatibility
4
+
9,10
of hard Zr ions and soft phosphine groups.
H L was syntheꢀ
3
1
1
Phosphine (PR )ꢀligated transition metal complexes have been
3
sized in a 55% overall yield according to Scheme 1. Heating a
essential to the development of organometallic chemistry and
homogeneous catalysis, as exemplified by Wilkinson’s catalyst
mixture of H L, ZrCl , and benzoic acid in DMF at 90 °C for 3
3
4
days afforded I in 34% yield as colorless needle crystals. Single
crystal diffractions of I with synchrotron radiation failed to afford
datasets of adequate resolution, presumably due to intrinsic disorꢀ
ders of the L ligands and framework distortion of I.
RhCl(PPh ) , Vaska’s complex IrCl(CO)(PPh ) , Crabtree’s cataꢀ
3
3
3 2
lyst [Ir(pyridine)(cod)(PCy) ]PF , and Grubb’s catalyst
3
6
1
(Ru(=CHPh)Cl (PCy ) ). The number of coordinating phosꢀ
2
3 2
phines control the metal’s catalytic activity and selectivity by
influencing its electronic and steric properties, as elegantly
demonstrated in Buchwald’s sterically hindered biarylꢀphosphines
which stabilize PdꢀPR complexes in CꢀX (X=C, N, O, etc) couꢀ
3
2
pling reactions. However, the number of phosphines on the metal
6
8
centers often changes during the d ꢀd catalytic cycles for Rh and
Ir catalysts because of their propensity to undergo disproportionaꢀ
tion reactions/ligand exchanges. We surmised that catalytic site
isolation in metalꢀorganic frameworks (MOFs) could prevent
Scheme 1. Synthesis of H L and P ꢀMOF (I). i) methylꢀ4ꢀ
3
1
boronobenzoate, PEPPSIꢀIPr, K CO , 1,4ꢀdioxane, 80 °C, 84%
deleterious
ligand
exchanges,
thus
stabilizing
the
2
3
yield; ii) HSiCl , TEA, mꢀxylene, 150 °C, 74% yield; iii) NaOH
mono(phosphine)ꢀM intermediates in catalytic cycles (Figure 1),
3
aq., THF, EtOH, 50 °C, 88% yield; iv) ZrCl , benzoic acid, DMF,
and constructed MOFs with MꢀPR complexes for the efficient
4
3
9
0
°C,
3
d, 34% yield. PEPPSIꢀIPr
=
[1,3ꢀBis(2,6ꢀ
catalysis of a broad range of organic reactions.
diisopropylphenyl)imidazolꢀ2ꢀylidene](3ꢀchloropyridyl)ꢀ
palladium(II) dichloride.
I has a solvent content of 83% by thermogravimetric analysis
2
and exhibits a BET surface area of 471 m /g by N sorption measꢀ
2
urements. Postsynthetic metalation of I with [RhCl(nbd)]2 or
[Ir(OMe)(cod)] afforded P ꢀMOFꢀRh (I•Rh) or P ꢀMOFꢀIr (I•Ir)
2
1
1
with controllable metal loadings. P ꢀMOFꢀM catalysts of low
1
metal loadings (14.9 mol% in I•Rh and 28.0 mol% in I•Ir), as
determined by ICPꢀMS of digested P ꢀMOFꢀM, were used for the
1
Figure 1. Catalytic site isolation stabilizes MꢀPR complexes in
MOFs by preventing disproportionation reactions/ligand exchangꢀ
es to significantly enhance their activities.
3
catalytic reactions to maintain large open channels in the MOFs
and facilitate diffusions of substrates and products. Powder Xꢀray
diffraction (PXRD) indicated that the crystallinity of I was mainꢀ
tained in both I•Rh and I•Ir (Figure 2c).
MOFs have emerged as a new class of porous molecular mateꢀ
rials for many potential applications such as gas storage, gas and
3
4
4a,5
liquid separations, chemical sensing, biomedical imaging,
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entry carbonyl
comꢀ
silane
catalyst
loading
time
(h)
yield
(%)
a
pound
(mol% Rh)
1
0.0005
20
36
I—Rh (after hydrogenation)
I—Rh (after hydrosilylation of alkenes)
I—Rh (after hydrosilylation of ketones)
I—Rh (pristine)
I—Ir (pristine)
I—Rh (simulated)
2
3
0.0005
0.05
140
5
93
95
0
b)
c)
HSiEt
3
b
4
0.0005
20
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
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9
0
1
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8
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0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
c
5
0.0005
0.005
20
60
0
6
HSiMe
2
Ph
90
5
10
15
20
2θ
6
3
0
3
6
8
4
d)
e)
7
8
9
HSiEt
HSiEt
HSiEt
HSiEt
3
3
3
0.05
0.01
0.01
80
140
60
85
90
95
94
0
-
-
|F.T. (Exp)|
|F.T. (Fit)|
Real (Exp)
Real (Fit)
-4
-8
|F.T. (Exp)|
|F.T. (Fit)|
Real (Exp)
Real (Fit)
0
2
4
6
0
2
4
6
R
(Å
)
R (Å)
Figure 2. a) Structures of I•Rh assembled from Zrꢀbased SBUs
and RhCl(nbd)(L) ligands. b) Graphic presentation of the
MCl(PR )(nbd) moieties in I•Rh as viewed along the (001) direcꢀ
tion c) PXRD patterns of I•Rh simulated from the CIF file
(black), freshly prepared I•Ir (red) and I•Rh (blue), and I•Rh
recovered from hydrosilylation of ketones (pink) and alkenes
green), hydrogenation of alkenes (violet). d) EXAFS spectra and
fits of I•Rh in R space showing the magnitude of Fourier Transꢀ
form (red hollow squares, red solid line) and real components
1
0
3
0.01
80
3
a
b
c
Isolated yield. RhCl(nbd)(PPh
norbornadiene.
3
) was used. RhCl(PPh
3
)
3
was used. nbd
=
I•Rh and I•Ir demonstrated excellent activity for several cataꢀ
lytic reactions. We first tested I•Rh for the hydrosilylation of
(
14,15
ketones with silanes (Table 1).
.5 eq. of triethylsilane in the presence of 0.0005 mol% I•Rh at r.t.
for 20 h gave (cyclohexyloxy)triethylsilane in 36% yield (TOF =
Reacting cyclohexanone and
1
(
hollow squares, dashed line). The fitting range is 1.2–5.2 Å in R
space (within the dashed lines). e) EXAFS spectra and fits of I•Ir
in R space showing the magnitude of Fourier Transform (red holꢀ
low squares, red solid line) and real components (hollow squares,
dashed line). The fitting range is 1.1–5.1 Å in R space (within the
dashed lines).
ꢀ1
16
3,600 h , entry 1, Table 1). Prolonging the reaction to 140 h
afforded the addition product in 93% yield, with a TON of
1
86,000 (entry 2, Table 1). A shorter reaction time (5 h) was
needed when the catalyst loading increased to 0.05 mol% (entry 3,
Table 1) In contrast, neither RhCl(nbd)(PPh ) nor Wilkinson’s
3
Interestingly, fully metalated I•Rh and I•Ir gave satisfactory
single crystal Xꢀray diffraction datasets under synchrotron radiaꢀ
tion. Both I•Rh and I•Ir crystallize in the triclinic space group P1
and adopt the llj topology by connecting the Zr (µ ꢀO) (µ ꢀOH)
4
SBU with 12 carboxylates from three L ligands. Unlike the UiO
structure, in which all carboxylates bridge Zr atoms, here, 10 of
2 carboxylates are bridging while the remaining two are monoꢀ
dentate, leaving each Zrꢀoxo SBU coordinating to two H O moleꢀ
cules. The void space was calculated to be 51.7% by PLATON.
Rh coordinates to one Cl, one nbd, and one phosphine ligand in
I•Rh (Figure 2a). The Ir coordination environment of I•Ir could
not be determined from Xꢀray diffractiondue to severe disorder.
catalyst as a homogeneous control gave any product under the
same conditions (entries 4 and 5, Table 1). We believe that the
site isolation of active catalysts in I•Rh is responsible for its highꢀ
er catalytic activity because only one ligand coordinates to the Rh
during the course of the reaction. Hydrosilylation proceeded for
several kinds of silanes and ketones that we tested. We found that
dimethylphenylsilane can be used for hydrosilylation (entry 6,
Table 1). Hydrosilylation of acetophenone gave the corresponding
alcohol in high yield (entry 7, Table 1). I•Rh also showed good
activity for deriving primary alcohols from aldehydes (entry 8,
Table 1). Sterically hindered ketones, such as diisopropyl ketone
and diꢀtertꢀbutyl ketone, could also be used in hydrosilylation,
probably due to the open environment around the monophosꢀ
phineꢀligated Rh center (entries 9 and 10, Table 1).
ꢀ
6
3
4
3
8
1
2
We also investigated the metal coordination environments in
I•Rh and I•Ir using Xꢀray absorption fine structure (XAFS) specꢀ
troscopy. We successfully used the crystal structure of
RhCl(nbd)(PPh ) to fit the EXAFS spectra of I•Rh and
RhCl(nbd)(PPh ) (Figure 2d). We used a model of Ir coordinatꢀ
ing to one methoxy, one bidentate cod, and one phosphine to fit
the XAFS spectra of I•Ir and Ir(OMe)(cod)(PPh ) (Figure 2e).
We found that I•Rh is also highly active in the hydrosilylation
of alkenes, a reaction frequently used in the industrial production
3
1
2
17
of consumer goods and fine chemicals. Hydrosilylation of 1ꢀ
3
octene with triethylsilane in the presence of 0.0001 mol% I•Rh at
13
r.t. for 20 h selectively gave the antiꢀMarkovnikovꢀtype addition
3
ꢀ
1
product in 34% yield (TOF = 17,000 h , entry 1, Table 2). Proꢀ
longing the reaction to 72 h afforded the addition product in 82%
yield (TON = 820,000, entry 2, Table 2). The reaction time can be
shortened to 4 h by increasing the catalyst loading to 0.05 mol%
Table 1. Hydrosilylation of carbonyls catalyzed by I•Rh
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(
entry 3, Table 2). The advantage of I•Rh over homogeneous
Many RhꢀPR3 compounds, including Wilkinson’s catalyst,
have been used to catalyze the hydrogenation of alkenes, but our
MOF more effectively catalyzed hydrogenation of substituted
alkenes at r.t. (Table 3). At 0.00005 mol% I•Rh loading, hydroꢀ
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
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5
5
5
6
controls was again demonstrated by comparison with
RhCl(nbd)(PPh ) or RhCl(PPh ) ; neither of which afforded any
3
3 3
product under the same conditions (entries 4 and 5, Table 2).
I•Rhꢀcatalyzed hydrosilylation reactions work well for various
silanes and alkenes. The hydrosilylation of 1ꢀoctene with dimeꢀ
thylphenylsilane and triethoxysilane gave 82% and 84% of the
addition product, respectively (entries 6 and 7, Table 2). We could
also hydrosilylate 1ꢀdecene and 6ꢀchloroꢀ1ꢀhexene with I•Rh
genation of 1ꢀoctene under 40 bar of H yielded 22% of octane,
2
ꢀ
1
giving a high TON of 440,000 (TOF = 17,000 h , entry 1, Table
3). Under the same conditions, hydrogenation with Wilkinson’s
catalyst afforded no conversion (entry 2, Table 3). At 0.0005
mol% catalyst loadings, I•Rh afforded the reduction product in a
quantitative yield (entry 3, Table 3). The reaction was completed
in 6 h at a higher catalyst loading of 0.01 mol% (entry 4, Table 3).
(entries 8 and 9, Table 2).
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
The hydrogenation of alkenes by I•Rh has a broad substrate
scope. With 0.0005 mol% catalyst loading, I•Rh converted styꢀ
rene and cyclohexene to the corresponding alkanes in almost
quantitative yields (entries 5 and 6, Table 3). Disubstituted alꢀ
kenes, such as αꢀmethyl styrene, were also good substrates (entry
7, Table 3). For the trisubstituted αꢀmethyl stilbene, 0.1 mol% of
I•Rh was needed to afford the reduction product in comparable
yields, which might be due to slow diffusion of the large substrate
through MOF channels (entry 8, Table 3). I•Rh displayed good
activity for a tetraꢀsubstituted alkene (entry 9, Table 3), while
Table 2. Hydrosilylation of alkenes catalyzed by I•Rh
entry
alkene
silane
catalyst
loading
time
(h)
yield
(%)
a
(mol% Rh)
1
2
3
0.0001
0.0001
0.05
20
72
4
34
82
81
HSiEt
3
18
Wilkinson’s catalyst showed no activity under the same reaction
conditions (entry 10, Table 3).
b
4
0.0001
0.0001
20
20
0
0
c
5
I•Rh could be recovered and reused at 9 to 19 times without
any loss of activity in each of the above reactions (Scheme S1, S3,
and S4, SI). We conducted several tests to demonstrate the heterꢀ
ogeneity of I•Rh. First, we showed that the PXRD of I•Rh recovꢀ
ered from each of the above reactions remained the same as that
of freshly prepared I•Rh (Figure 2c). Second, we used ICPꢀMS to
show that the amounts of Rh and Zr leaching into the supernatant
during the hydrosilylation of cyclohexanone and 1ꢀoctene and
hydrogenation of 1ꢀoctene were less than 1.3%/0.1%,
6
7
8
9
HSiMe
2
Ph
0.0005
0.005
40
40
40
40
82
84
84
HSi(OEt)
3
HSiEt
HSiMe
3
0.0005
2
Ph
0.0005
83
1
.1%/0.03%, and 2.0%/0.17%, respectively. Finally, we observed
a
b
c
Isolated yield. RhCl(nbd)(PPh
3
) was used. RhCl(PPh
3
)
3
was used.
that the removal of I•Rh from the reaction mixture after several
hours stopped the hydrosilylation of cyclohexanone and the hyꢀ
drogenation of 1ꢀoctene (Scheme S2 and S5, SI).
Table 3. Hydrogenation of alkenes by I•Rh
Table 4. CꢀH active borylation of arenes by I•Ir
a
catalyst
loading
entry
alkene
catalyst
yield
entry
arene
product
catalyst loading
yield
(%)
(mol% Rh)
a
(mol% Ir)
b
1
2
3
I•Rh
RhCl(PPh
I•Rh
0.00005
0.00005
0.0005
0.01
22
1
2
0.1
0.2
4
84
3
)
3
0
123
118
13
b
100
100
3
c
c
4
I•Rh
4
0.1
5
6
I•Rh
I•Rh
0.0005
0.0005
98
99
5
0.2
0.2
0.2
120
(o:m:p
=
=
9
:63:28)
6
7
114
o:m:p
81:11:8)
(
7
I•Rh
I•Rh
0.0005
0.1
99
99
117 (3:4
= 74:26)
8
9
a
b
c
Isolated yield based on B
2
(pin)
2
.
3 h. Ir(OMe)(cod)(PPh
3
) was used.
I•Rh
0.001
0.001
81
0
pin = pinacolate, cod = 1,5ꢀcyclooctadiene.
1
0
3 3
RhCl(PPh )
a
b
c
Isolated yield. NMR yield based on CH
3
NO
2
as an internal standard.
6
Direct CꢀH borylation of arenes is a powerful method for obꢀ
taining arylboronates, useful synthons for accessing a broad range
h.
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1
9
of compounds, directly from arenes. We tested I•Ir for the
Research Collaborative Access Team (MRCAT) and Sector 20.
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
borylation reaction with B Pin . In the presence of 0.1 mol% of
MRCAT operations are supported by the DOE and the MRCAT
member institutions. Sector 20 operations are supported by the US
Department of Energy and the Canadian Light Source. Use of the
APS, an Office of Science User Facility operated for the U.S.
Department of Energy (DOE) Office of Science by ANL, was
supported by the U.S. DOE (DEꢀAC02ꢀ06CH11357).
2
2
I•Ir, benzene was borylated to give PhBPin in 84% yield at 90 °C
2
0
for 40 h (TOF = 21, entry 1, Table 4). The borylated product
was obtained in 123% isolated yield with 0.2 mol% catalyst (entry
21
2
, Table 4,) Increasing the catalyst loading to 4 mol% shortened
the reaction time to 3 h (entry 3, Table 4). The homogeneous
control, Ir(OMe)(cod)(PPh ), gave only 13% yield under identical
3
conditions (entry 4, Table 4). We also tested I•Ir as a catalyst for
the borylation of several kinds of substituted arenes. 0.2 mol% of
I•Ir catalyzed the borylation of toluene to afford a mixture of
borylated products in 120% yield (o:m:p = 9:63:28, entry 5, Table
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(2) Martin, R.; Buchwald, S. L. Acc. Chem. Res. 2008, 41, 1461ꢀ1473.
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5
6
7
8
9
0
4
). The orthoꢀselective arene borylation was achieved using an
arene with the carboxylate directing group (entry 6, Table 4). We
found that the borylation of 1,2ꢀdichlorobenzene occurred preferꢀ
entially at the 3 positions (entry 7, Table 4). We then investigated
the nature of Ir species involved in CꢀH borylation. EXAFS studꢀ
ies indicated the formation of fiveꢀcoordinate Ir(PPh )(Bpin) (η ꢀ
2
012, 112, 782ꢀ835. (b) Dincă, M.; Long, J. R. Angew. Chem., Int. Ed.
2008, 47, 6766ꢀ6779. (c) Rowsell, J. L. C.; Yaghi, O. M. Angew. Chem.,
Int. Ed. 2005, 44, 4670ꢀ4679.
3
3
2
(4) (a) Liu, D.; Lu, K.; Poon, C.; Lin, W. Inorg. Chem. 2014, 53, 1916ꢀ
COD) species upon treating I•Ir with excess of B (pin) , suggestꢀ
2
2
1924. (b) Kreno, L. E.; Leong, K.; Farha, O. K.; Allendorf, M.; Van
Duyne R. P.; Hupp, J. T. Chem. Rev. 2012, 112, 1105ꢀ1125. (c) Cui, Y.;
Yue, Y.; Qian G.; Chen, B. Chem. Rev. 2012, 112, 1126ꢀ1162.
ing the ability to maintain mono(phosphine) coordination on the Ir
center during the catalytic cycle (Figure S10, Table S4). We
demonstrated the heterogeneity of I•Ir with a reuse experiment
(
5) Lin, W.; Rieter, W. J.; Taylor, K. M. L. Angew. Chem., Int. Ed.
009, 48, 650ꢀ658.
6) Rocca, J. D.; Liu, D.; Lin, W. Acc. Chem. Res. 2011, 44, 957ꢀ968.
(7) (a) Gascon, J.; Corma, A.; Kapteijn, F.; Llabrés i Xamena, F. X.;
2
(Scheme S6, SI), the similarity of PXRD patterns of I•Ir before
(
and after borylation (Figure S14, SI), and by measuring the very
low leaching of Ir (0.9%) and Zr (0.007%) during the borylation
reaction.
ACS Catal. 2014, 4, 361ꢀ378. (b) Zhao, M.; Ou, S.; Wu, C.ꢀD. Acc. Chem.
Res. 2014, 47, 1199ꢀ1207. (c) Yoon, M.; Srirambalaji, R.; Kim, K. Chem.
Rev. 2012, 112, 1196ꢀ1231. (d) Ma, L.; Abney, C.; Lin, W. Chem. Soc.
Rev. 2009, 38, 1248ꢀ1256. (e) Lee, J.; Farha, O. K.; Roberts, J.; Scheidt,
K. A.; Nguyen, S. Hupp, T.; J. T. Chem. Soc. Rev. 2009, 38, 1450ꢀ1459.
In summary, we report the first example of a porous and crysꢀ
talline ZrꢀMOF based on a triarylphosphineꢀderived tricarboxylate
linker, and its postsynthetic metalation with Rh and Ir to afford
singleꢀsite mono(phosphine)ꢀM catalysts for the hydrosilylation of
ketones and alkenes, the hydrogenation of alkenes, and the CꢀH
borylation of arenes. The MOF catalysts not only showed superior
activity to the corresponding homogeneous controls but can also
be reused multiple times without any loss of catalytic activity. We
believe that the ability to maintain mono(phosphine) coordination
during the catalytic cycle in MOFs should afford interesting opꢀ
portunities for the design of other highly active and selective cataꢀ
lysts for a broad range of organic reactions.
(
8) Cavka, J. H.; Jakobsen, S.; Olsbye, U.; Guillou, N.; Lamberti, C.;
Bordiga, S.; Lillerud, K. P. J. Am. Chem. Soc. 2008, 130, 13850ꢀ13851.
9) (a) Nuñez, A. J.; Shear, L. N.; Dahal, N.; Ibarra, I. A.; Yoon, J.;
(
Hwang, Y. K.; Chang, J.ꢀS.; Humphrey, S. M. Chem. Commun. 2011, 47,
11855ꢀ11857. (b) Redondo, A. B.; Morel, F. L.; Ranocchiari, M.; van
Bokhoven, J. A. ACS Catal. 2015, 5, 7099ꢀ7103.
(10) (a) Bohnsack, A. M.; Ibarra, I. A.; Bakhmutov, V. I.; Lynch, V.
M.; Humphrey, S. M. J. Am. Chem. Soc. 2013, 135, 16038ꢀ16041. (b)
Falkowski, J. M.; Sawano, T.; Zhang, T.; Tsun, G.; Chen, Y.; Lockard, J.
V.; Lin, W. J. Am. Chem. Soc. 2014, 136, 5213ꢀ5216. (c) Sawano, T.;
Thacker, N. C.; Lin, Z.; McIsaac, A. R.; Lin, W. J. Am. Chem. Soc. 2015,
1
37, 12241ꢀ12248. (d) Burgess, S. A.; Kassie, A.; Baranowski, S. A.;
ASSOCIATED CONTENT
Fritzsching, K. J.; SchmidtꢀRohr, K.; Brown, C. M.; Wade, C. R. J. Am.
Chem. Soc. 2016, 138, 1780ꢀ1783.
Supporting Information
(
11) Václavík, J.; Servalli, M.; Lothschütz, C.; Szlachetko, J.;
Ranocchiari, M.; van Bokhoven, J. A. ChemCatChem 2013, 5, 692ꢀ696.
12) Sparkes, H. A.; Brayshaw, S. K.; Weller, A. S.; Howard, J. A. K.,
General experimental section; synthesis and characterization of
(
ligands, and P ꢀMOF; crystal structure figure and crystallographic
1
Acta Cryst. 2008, B64, 550ꢀ557.
(13) The model is derived from two crystal structures. (CCDC number:
data of I•Rh (CIF); details of the XAFS experiments, fitting
method and model; procedures for MOFꢀcatalyzed reactions. This
material is available free of charge via the Internet at
http://pubs.acs.org.
7
5
00005 and 1155618).
14) DíezꢀGonzález, S.; Nolan, S. P. Org. Prep. Proc. Int. 2007, 39,
23ꢀ559.
15) Hamasaka, G.; Kawamorita, S.; Ochida, A.; Akiyama, R.; Hara,
(
(
AUTHOR INFORMATION
K.; Fukuoka, A.; Asakura, K.; Chun, W. J.; Ohmiya, H.; Sawamura, M.
Organometallics 2008, 27, 6495ꢀ6506.
Corresponding Author
(
16) I•Rh with 56 mol% Rh loading (relative to phosphine equivalents)
gave 24% yield under the same reaction conditions.
17) (a) Marciniec, B. Coord. Chem. Rev. 2005, 249, 2374ꢀ2390. (b)
wenbinlin@uchicago.edu
(
Marciniec, B.; Guliński, J.; Urbaniak, W.; Kornetka, Z. W.
Comprehensive Handbook on Hydrosilylation; Pergamon: Oxford, 2002.
Notes
The authors declare no competing financial interest.
(c) Roy, A. K. Adv. Organomet. Chem. 2007, 55, 1ꢀ59.
(18) Crabtree, R. Acc. Chem. Res. 1979, 12, 331ꢀ337.
ACKNOWLEDGMENT
(19) Mkhalid, I. A. I.; Barnard, J. H.; Marder, T. B.; Murphy, J. M.;
Hartwig, J. F. Chem. Rev. 2010, 110, 890ꢀ931.
(20) Kawamorita, S.; Ohmiya, H.; Hara, K.; Fukuoka, A.; Sawamura,
M. J. Am. Chem. Soc. 2009, 131, 5058ꢀ5059.
We thank NSF (CHEꢀ1464941) for financial support and C. Poon
for experimental help. Single crystal diffraction studies were perꢀ
formed at ChemMatCARS (Sector 15), APS, Argonne National
Laboratory (ANL). ChemMatCARS is principally supported by
NSF/CHEꢀ1346572 from the NSF Divisions of Chemistry (CHE)
and Materials Research (DMR). XAFS data were collected at the
APS at ANL on Beamline 10BMꢀB, supported by the Materials
(21) Over 100% yield of the borylated product is attributed to some
reactivity of I•Ir to HBpin generated as byproduct during the borylation
reaction. With 0.2 mol% Ir of I•Ir, the CꢀH active borylation with HB(pin)
gave 13% yield.
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