Postsynthetic modification of dicarbene-derived metallacycles via photochemical [2 + 2] cycloaddition

Article abstract of DOI:10.1021/ja4032067

Molecular squares obtained from two olefin-bridged bis(NHC) ligands, NHC-Ar-C=C-Ar-NHC, and two Ag⁺ or Au⁺ ions undergo postsynthetic modifications via a UV-irradiation-initiated [2 + 2] cycloaddition reaction to yield the corresponding cyclobutane-bridged dinuclear tetrakis(NHC) complexes. The tetrakis(NHC) ligand can be liberated from the Ag^I complexes as the tetraimidazolium salt. For the Au^I complexes, the substituents at N3 and N3′ of the dicarbene ligands determine the outcome of the reaction in the solid state.

Full text of DOI:10.1021/ja4032067

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Communication
Postsynthetic Modification of Dicarbene-Derived
Metallacycles via Photochemical [2+2] Cycloaddition
Ying-Feng Han, Guo-Xin Jin, and F. Ekkehardt Hahn
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/ja4032067 • Publication Date (Web): 03 Jun 2013
Downloaded from http://pubs.acs.org on June 4, 2013
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Postsynthetic Modification of Dicarbene-Derived
Metallacycles via Photochemical [2+2] Cycloaddition
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YingꢀFeng Han,†,‡ GuoꢀXin Jin,‡ and F. Ekkehardt Hahn*,†
†Institut für Anorganische und Analytische Chemie, Westfälische WilhelmsꢀUniversität Münster, Corrensstraße 30, Dꢀ48149
Münster, Germany
‡Department of Chemistry, Fudan University, 220 Handan Road, 200433 Shanghai, P. R. China
Supporting Information Placeholder
In this contribution we report dinuclear AgI and AuI
molecular rectangles featuring olefin bridged dicarbene
ligands. These assemblies function as scaffolds for the
ABSTRACT: Molecular squares obtained from two olefin
substituted di(NHC) ligands NHC−Ar−C=C−Ar−NHC and
two Ag+ or Au+ ions undergo postsynthetic modifications via a
photodimerization of the olefinic bonds to yield cyclobutane
UVꢀirradiation initiated [2+2] cycloaddition reaction to yield
units within the molecular rectangles both in solution (AgI and
the cyclobutane bridged dinuclear tetra(NHC) complexes. The
AuI complexs) and in the solid state (AuI complexes) (Scheme
tetra(NHC) ligand can be liberated from the AgI complexes as
tetraimidazolium salt. For the AuI complexes, the N3,N3’
1). The alignment of the C=C double bonds and thus the speed
of the cycloaddition reaction in the solid state are influenced
substituents of the dicarbene ligands determine the outcome of
by the N3,N3’ꢀsubstituents of the dicarbene ligands.
the reaction in the solid state.
Scheme 1. Preparation and Reactions of Dicarbene-
Bridged Molecular Rectangles
Metalꢀligand directed assembly has led to a large number of
metalꢀorganic assemblies like metalꢀorganic frameworks
2 PF6
R
2 PF6
(MOFs) and different metalꢀorganic polyhedra. Until recently,
only molecular architectures build from Wernerꢀtype
complexes featuring oxygen or nitrogen donor atoms were
known.1 Recently Nꢀheterocyclic carbenes (NHCs)2 have been
2 PF6
R
R
R
R
N
N
N
N
N
Ag
Au
N
N
N
N
N
2 Ag2O, CH3CN
55 oC, 20 h
used for the generation
of organometallic molecular
Au(THT)Cl
transmetallation
2
assemblies featuring a framework of metal−carbon bonds.
Among others, silver(I)ꢀNHC complexes played an important
role in this development based on their facile accessibility via
the Ag2O route, the stability of the Ag−CNHC bond and the
possibility to transmetalate the NHC ligand to other metal
N
N
N
N
N
Ag
Au
N
N
R
N
R
N
N
R
R
R
R = Et: [Au2(1)2](PF6)2
R = nBu: [Au2( )2](PF6)2
R = Et: H2-1(PF6)2
R = nBu: H2-2(PF6)2
R = Et: [Ag2(1)2](PF6)2
R = nBu: [Ag2(2)2](PF6)2
centers.3 Today,
a
number of molecular squares and
2
rectangles,4 cylinderꢀlike structures5 and organometallic
polymers6 held together by M−CNHC bonds is known.
solution
hv
solution
solid state
hv
365 nm
hv
365 nm
365 nm
4 PF6
The subsequent functionalization of organometallic
polyhedra obtained from poly(NHC) ligands has not been
described yet. Such postsynthetic modifications (PSM) have
been shown to be broadly applicable for the preparation of a
variety MOFs which would be difficult to obtain via other
synthetic protocols.7 In addition, various postꢀassembly
modification of discrete assemblies have also been reported.8
The photochemical induced [2+2] cycloaddition reaction
constitutes a classical PSM of metalꢀorganic polyhedra based
on Werner type ligands. This reaction, leading to cyclobutanes,
requires the presence of two properly aligned C=C double
bonds (parallel arrangement, separation less than 4.2 Å). It has
been performed in the solid state9 and in solution10 utilizing
inclusion,10 hydrogen bond11 or coordination driven12
molecular assemblies. The application of the [2+2]
cycloaddition for the PSM of NHC based assemblies has not
been demonstrated yet.
R
R
R
R
2 PF6
R
R
N
2 PF6
N
N
N
N
N
Au
Ag
N
N
N
N
N
N
1. NH4Cl
2. NH4PF6
Au(THT)Cl
transmetallation
N
N
N
N
N
N
Au
Ag
N
N
N
R
N
N
N
R
R
R
R
R
R = Et: H4-3(PF6)4
R = nBu: H4-4(PF6)4
R = Et: [Ag2(3)](PF6)2
R = nBu: [Ag2(4)](PF6)2
R = Et: [Au2(3)](PF6)2
R = nBu: [Au2(4)](PF6)2
We4c,13a and others13b−e have prepared dinuclear molecular
rectangles of type [M2(dicarbene)2]2+ (M = AgI, AuI). In case
of aryl bridged dicarbenes, transannular separations as short as
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3.6 Å13b have been observed, most likely caused by πꢁꢁꢁπ
stacking interactions. This type of ring positioning and the
M−CNHC bond lengths of about 2.0 Å indicate the suitability of
the [M2(dicarbene)2]2+ scaffold for an intramolecular [2+2]
cycloaddition provided a suitable olefin bridged dicarbene
ligand can be introduced.
The olefin complexes [Ag2(1)2](PF6)2 and [Ag2(2)2](PF6)2
can be isolated but attempts to characterize them by Xꢀray
diffraction failed as UVꢀirradiation in addition to the light
sensitivity of the compounds caused decomposition. This
sensitivity, which was not observed in solution, also prevented
us to study the singeꢀcrystal to singeꢀcrystal transformations
[Ag2(1)2](PF6)2 → [Ag2(3)](PF6)2 and [Ag2(2)2](PF6)2
[Ag2(4)](PF6)2 in detail.
→
To achieve this goal we have prepared the structurally
similar dimidazolium substituted stilbene derivatives H2ꢀ
1(PF6)2 and H2ꢀ2(PF6)2 from transꢀ4,4′ꢀdibromostilbene using
reported precedures.13 The reaction of equimolar amounts of
Ag2O and H2ꢀ1(PF6)2 or H2ꢀ2(PF6)2 in acetonitrile yielded the
dinuclear silver tetracarbene complexes [Ag2(1)2](PF6)2 and
[Ag2(2)2](PF6)2 in good yields of 92% and 90%, respectively.
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An Xꢀray diffraction analysis with crystals of
[Ag2(4)](PF6)2ꢁ2MeCN confirmed the cyclobutane formation
(Figure 2). The cation [Ag2(4)]2+ resides on a crystallographic
inversion center. The metric parameters (Ag−CNHC 2.082(3)
and 2.084(3) Å, CNHC−Ag−CNHC 177.09(10)o) fall in the ranges
previously observed for linearly coordinated di(NHC) silver
complexes.3,5a,5c,5d,5e,13 The cyclobutane ring features typical
single bond C−C distances but strongly distorted C−C−C
angles of about 90°.
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Formation of the molecular rectangles was confirmed by H
and 13C{1H} NMR spectroscopy
[Ag2(1)2](PF6)2 and 180.30 for [Ag2(2)2](PF6)2) and by ESI or
(
δNCN
= 178.21 for
MALDIꢀTOF mass spectrometry [Scheme 1;
Supporting Information (SI)].
see the
The metallacycles [Ag2(1)2](PF6)2 and [Ag2(2)2](PF6)2 were
tested for postsynthetic modification via a photochemical
induced [2+2] cycloaddition reaction. Irradiation (Hg lamp,
365 nm) of [Ag2(1)2](PF6)2 in DMSOꢀd6 and [Ag2(2)2](PF6)2 in
CD3CN result in a rapid conversion into the corresponding
dinuclear rcttꢀcyclobutane silver complexes [Ag2(3)](PF6)2
and [Ag2(4)](PF6)2. The [2+2] cycloadditions were completed
after 2.5 h, and the conversions were essentially quantitative
and stereospecific, as judged from 1H and 13C{1H} NMR
spectroscopy (Figure 1; see also SI).
Figure 2. Molecular structure of the dication [Ag2(4)]2+ (50%
probability ellipsoids, hydrogen atoms have been omitted for
clarity, the cation resides on a crystallographic inversion
center). Selected bond lengths (Å) and angles (deg): Ag−C1
2.082(3), Ag−C15 2.084(3), N1−C1 1.357(3), N2−C1
1.353(3), N3−C15 1.359(3), N4−C15 1.349(3), C14−C28
1.551(3), C14−C28* 1.583(4); C1−Ag−C15 177.09(10),
N1−C1−N2 104.1(2), N3−C15−N4 104.0(2), C28−C14−C28*
89.4(2), C14−C28−C14* 90.6(2).
Since the [2+2] cycloaddition could not be studied in the
solid state with the silver olefin complexes [Ag2(1)2](PF6)2 and
[Ag2(2)2](PF6)2, we searched for more stable molecular
rectangles bridged by the olefin functionalized di(NHC)
ligands 1 or 2. The dinuclear silver complexes [Ag2(1)2](PF6)2
and [Ag2(2)2](PF6)2, like many other silverꢀNHC complexes,
undergo transmetalation with [Au(THT)Cl] (THT
=
tetrahydrothiophene)5d,e to give the corresponding gold
complexes with retention of the twoꢀdimensional structure in
75% and 68% yield respectively (Scheme 1; see also SI). The
gold(I) complexes [Au2(1)2](PF6)2 and [Au2(2)2](PF6)2 were
fully characterized by NMR spectroscopy and mass
spectrometry. A subsequent photolysis reactions in CD3CN
Figure 1. Section of the 1H NMR spectra (400 MHz, 300K) of
[Ag2(2)2](PF6)2 in CD3CN before (a) and after (b) UVꢀ
irradiation and of [Ag2(1)2](PF6)2 in DMSOꢀd6 before (c) and
after (d) UVꢀirradiation.
1
The HNMR spectra of [Ag2(3)](PF6)2 and [Ag2(4)](PF6)2
solution (UV,
λ = 365 nm) produced the desired dinuclear
displayed sharp singlets at 4.74 and 4.73 ppm corresponding
to a single cyclobutane environment (Figure 1) instead of the
resonances for the olefinic protons at 7.35 and 7.10 ppm,
respectively. This observation is consistent with a previous
report on the related tetra(pyridine)ꢀsubstituted cyclobutane
ligand 4,4′ꢀtpcb (where 4,4′ꢀtpcb = rcttꢀtetrakisꢀ(4ꢀpyridyl)ꢀ
cyclobutane).12c The 13C{1H} NMR spectra of [Ag2(3)](PF6)2
and [Ag2(4)](PF6)2 also feature the typical signals12c for the
cyclobutane carbon atoms at 43.89 and 45.54 ppm (see also
SI).
rcttꢀcyclobutane gold(I) complexes [Au2(3)](PF6)2 and
[Au2(4)](PF6)2 in quantitatively yields as established by NMR
spectroscopy (Scheme 1; see also SI). Alternatively,
complexes [Au2(3)](PF6)2 and [Au2(4)](PF6)2 can be obtained
from the silver(I) complexes [Ag2(3)](PF6)2 and [Ag2(4)](PF6)2
by a transmetalation reaction in acetonitrile. Yields of about
90% and retention of the metallosupramolcular scaffold were
observed in these transmetalation reactions.
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Surprisingly, the intramolecular [2+2] cycloaddition
3(PF4)4] and 8.76 ppm [H4ꢀ4 (PF6)4] for the four imidazolium
C2ꢀH protons and at 4.80 ppm for the four cyclobutane
protons. ESIꢀMS spectrometry provided further evidence for
the formation of the tetraimidazolium salts (see also SI).
The silver(I) complexes [Ag2(1)](PF6)2−[Ag2(2)](PF6)2, but
not the analogous gold(I) complexes are sensitive to light. In
no case have we observed retrocyclization. The cyclobutaneꢀ
bridged silver(I) and gold(I) complexes are stable in
acetonitrile solution for weeks (under exclusion of light for the
silver(I) complexes) and such solutions can be heated up to
60 °C without any sign of retrocyclization. The same is true
for the cyclobutaneꢀlinked tetraimidazolium salts H4ꢀ3(PF6)4
and H4ꢀ4(PF6)4 which are stable for weeks in MeOH or DMSO
solution or in the solid state without any signs of
retrocyclization.
In summary, we have demonstrated that photochemical [2+2]
cycloaddition reactions can be effectively used to modify
metallacycles with bridging dicarbene ligands featuring
internal olefin groups. Both the olefine bridged dicarbene
ligands as well as the cyclobutane bridged tetracarbene ligands
can be transmetalated from AgI to AuI, a feature which is
generally not available for polydentate Werner type ligands
bridged by olefins or cyclobutane. After the [2+2]
cycloaddition, the generated cyclobutane bridged tetracarbene
ligands can be liberated from the silver(I) complexes as
tetraimidazolium salts and this type of reaction might find
applications in organic synthesis for the preparation of
polyimidazolium salts. Finally, we have demonstrated that the
N3,N3’ substitution pattern of the olefinꢀbridged NHCs can
influence the outcome of the [2+2] cycloaddition in the solid
state. Work in progress is directed to expand this approach to
more than two reaction centers and higher dimensional olefins.
reaction of [Au2(1)2](PF6)2 and [Au2(2)2](PF6)2 in the solid
state proceeded with different results. When a powdered
crystalline sample of [Au2(1)2](PF6)2 was irradiated with a
mercury lamp (λ = 365 nm) for 12 h, the [2+2] cycloaddition
readily proceeded and the cyclobutane derivative
[Au2(3)](PF6)2 was obtained in quantitative yield. NMR
spectroscopy confirmed that no byproducts were formed (see
SI, Figure S65). In contrast to this, the [2+2] cycloaddition of
the Nꢀbutyl substituted derivative [Au2(2)2](PF6)2 in the solid
states was quite slow and only 25% of [Au2(4)](PF6)2 together
with unreacted [Au2(2)2](PF6)2 were obtained after UV
irradiation of a powdered crystalline sample of [Au2(2)2](PF6)2
for 72 h. This low yield indicated that the alignment of the
C=C double bonds in [Au2(2)2](PF6)2 in the solid state might
not be suitable for the cycloaddition reaction. An Xꢀray
diffraction study with crystals of [Au2(2)2](PF6)2 (Figure 3, top)
revealed that interactions of the Nꢀbutyl substituents of the
NHC donors enforced a rotation of one {Au(NHC)2} unit
relative to the other one. As a consequence, the two C=C
double bonds in cation [Au2(2)2]2+ are oriented almost
perpendicular to each other (Figure 3, bottom left) while the
C=C bonds in the sterically less encumbered cation [Au2(1)2]2+
(for full details of the molecular structure determination of
[Au2(1)2](ClO4)2 see SI) are oriented in a parallel fashion thus
enabling the observed rapid [2+2] cycloaddition.
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ASSOCIATED CONTENT
Supporting Information. Experimental details for the
synthesis of all compounds and Xꢀray crystallographic files for
compounds [Ag2(4)](PF6)2ꢁ2CH3CN, [Au2(1)2](ClO4)2, and
[Ag2(2)2](PF6)2ꢁCH3CN in CIF format. This material is available
free of charge via the Internet at http://pubs.acs.org.
Figure 3. Molecular structure of the dication [Au2(2)2]2+ (top,
hydrogen atoms have been omitted for clarity) and view of the
arrangement of the C=C double bonds in cations [Au2(2)2]2+
(bottom left) and [Au2(1)2]2+ (bottom right). Selected bond
lengths (Å) and angles (deg): Au1−C1 2.022(5), Au1−C15
2.027(5), Au2−C29 2.025(5), Au2−C43 2.020(5), N1−C1
1.357(6), N2−C1 1.347(6), N3−C15 1.351(7), N4−C15
1.354(6), N5−C29 1.341(6), N6−C29 1.361(6), N7−C43
1.343(6), N8−C43 1.356(7); C1−Au1−C15 174.2(2),
C29−Au2−C43 173.8(2), N1−C1−N2 104.7(4), N3−C15−N4
104.5(4), N5−C29−N6 105.0(4), N7−C43−N8 104.4(4).
AUTHOR INFORMATION
Coresponding Author
fehahn@uniꢀmuenster.
ACKNOWLEDGEMENT
The authors thank the Deutsche Forschungsgemeinschaft (SFB
858) for financial support. YFH thanks the Alexander von
Humboldt Foundation for financial support.
REFERENCES
(1) (a) Leininger, S.; Olenyuk, B.; Stang, P. J. Chem. Rev. 2000, 100,
853−908. (b) Swiegers, G. F.; Malefetse, T. J. Chem. Rev. 2000, 100,
3483−3537. (c) Fujita, M.; Tominaga, M.; Hori, A.; Therrien, B. Acc.
Chem. Res. 2005, 38, 369−380. (d) Gianneschi, N. C.; Masar III, M. S.;
Mirkin, C. A. Acc. Chem. Res. 2005, 38, 825−837. (e) Pluth, M. D.;
Raymond, K. N. Chem. Soc. Rev. 2007, 36, 161−171. (f) Kreickmann, T.;
Hahn, F. E. Chem. Commun. 2007, 1111−120. (g) Han, Y.ꢀF.; Jia, W.ꢀG.;
Yu, W.ꢀB.; Jin, G.ꢀX. Chem. Soc. Rev. 2009, 38, 3419−3434. (h)
Northrop, B. H.; Zheng, Y.ꢀR.; Chi, K.ꢀW.; Stang, P. J. Acc. Chem. Res.
2009, 42, 1554−1563. (i) Han, Y.ꢀF.; Li, H.; Jin, G.ꢀX. Chem. Commun.
2010, 46, 6879−6890. (j) Chakrabarty, R.; Mukherjee, P. S.; Stang, P. J.
The cyclobutaneꢀbridged tetacarbene ligands from the silver
complexes [Ag2(3)](PF6)2 and [Ag2(4)](PF6)2 can be liberated
as the tetrakis(imidazolium) salts by reaction of the complexes
with NH4Cl in MeOH. The initially formed chloride salts have
been converted into H4ꢀ3(PF6)4 and H4ꢀ4(PF6)4 by reactions of
with NH4PF6 in MeOH (total yield 705 and 68% respectively).
In both cases, only one tetrakis(imidazolium) salt was
observed which was confirmed by NMR spectroscopy. The 1H
NMR spectra feature sharp singlets (ratio 1:1) at 8.77 [H4ꢀ
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2
3
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7
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9
Chem. Rev. 2011, 111, 6810−6918.
1239−1248. (b) MacGillivray, L. R.; Papaefstathiou, G. S.; Friščić, T.;
(2) (a) Mata, J. A.; Poyatos, M.; Peris, E. Coord. Chem. Rev. 2007, 251,
841−859. (b) Hahn, F. E.; Jahnke, M. C. Angew. Chem., Int. Ed. 2008, 47,
3122−3172. (c) Poyatos, M.; Mata, J. A.; Peris, E. Chem. Rev. 2009, 109,
3677−3707. (d) Mercs, L.; Albrecht, M. Chem. Soc. Rev. 2010, 39,
1903−1912. (e) Melaimi, M.; Soleilhavoup, M.; Bertrand, G. Angew.
Chem., Int. Ed. 2010, 49, 8810−8849.
Hamilton, T. D.; Bucăr, D.ꢀK.; Chu, Q.; Varshney, D. B.; Georgiev, I. G.
Acc. Chem. Res. 2008, 41, 280−291. (c) Nagarathinam, M.; Peedikakkal,
A. M. P.; Vittal, J. J. Chem. Commun. 2008, 5277−5288.
(10) (a) Pattabiraman, M.; Natarajan, A.; Kaanumalle, L. S.;
Ramamurthy, V. Org. Lett. 2005, 7, 529−532. (b) Nishioka, Y.;
Yamaguchi, T.; Yoshizawa, M.; Fujita, M. J. Am. Chem. Soc. 2007, 129,
7000−7001. (c) Maddipatla, M. V. S. N.; Kaanumalle, L. S.; Natarajan,
A.; Pattabiraman, M.; Ramamurthy, V. Langmuir 2007, 23, 7545−7554.
(11) (a) Caronna, T.; Liantonio, R.; Logothetis, T. A.; Metrangolo, P.;
Pilati, T.; Resnati, G. J. Am. Chem. Soc. 2004, 126, 4500−4501. (b)
MacGillivray, L. R. J. Org. Chem. 2008, 73, 3311−3317.
(12) (a) Chu, Q.; Swenson, D. C.; MacGillivray, L. R. Angew. Chem.,
Int. Ed. 2005, 44, 3569−3572. (b) Eubank, J. F.; Kravtsov, V. C.;
Eddaoudi, M. J. Am. Chem. Soc. 2007, 129, 5820−5821. (c) Han, Y.ꢀF.;
Lin, Y.ꢀJ.; Jia, W.ꢀG.; Wang, G.ꢀL.; Jin, G.ꢀX. Chem. Commun. 2008,
1807−1809. (d) Santra, R.; Biradha, K. Cryst. Growth Des. 2010, 10,
3315−3320. (e) Zhang, W.ꢀZ.; Han, Y.ꢀF.; Lin, Y.ꢀJ.; Jin, G.ꢀX.
Organometallics 2010, 29, 2842−2849. (f) Liu, D.; Ren, Z.ꢀG.; Li, H.ꢀX.;
Lang, J.ꢀP.; Li, N.ꢀY.; Abrahams, B. F. Angew. Chem., Int. Ed. 2010, 49,
4767−4770. (g) Mir, M. H.; Koh, L. L.; Tan, G. K.; Vittal, J. J. Angew.
Chem., Int. Ed. 2010, 49, 390−393. (h) Yu, W.ꢀB.; Han, Y.ꢀF.; Lin, Y.ꢀJ.;
(3) (a) Garrison, J. C.; Youngs, W. J. Chem. Rev. 2005, 105,
3978−4008. (b) Lin, I. J. B.; Vasam, C. S. Coord. Chem. Rev. 2007, 251,
642−670. (c) Lin, J. C. Y.; Huang, R. T. W.; Lee, C. S.; Bhattacharyya,
A.; Hwang, W. S.; Lin, I. J. B. Chem. Rev. 2009, 109, 3561−3598.
(4) (a) Hahn, F. E.; Radloff, C.; Pape, T.; Hepp, A. Organometallics
2008, 27, 6408−6410. (b) Radloff, C.; Hahn, F. E.; Pape, T.; Fröhlich, R.
Dalton Trans. 2009, 7215−7222. (c) Radloff, C.; Weigand, J. J.; Hahn, F.
E. Dalton Trans. 2009, 9392−9394. (d) Conrady, F. M.; Fröhlich, R.;
Schulte to Brinke, C.; Pape, T.; Hahn, F. E. J. Am. Chem. Soc. 2011, 133,
11496−11499. (e) Schmidtendorf, M.; Pape, T.; Hahn, F. E. Angew.
Chem., Int. Ed. 2012, 51, 2195−2198. (f) Viciano, M.; Sanaú, M.; Peris, E.
Organometallics 2007, 26, 6050−6054.
(5) (a) Hahn, F. E.; Radloff, C.; Pape, T.; Hepp, A. Chem.
2008, 14, 10900−10904. (b) Radloff, C.; Gong, H.ꢀY.; Schulte to Brinke,
C.; Pape, T.; Lynch, V. M.; Sessler, J.; Hahn, F. E. Chem. Eur. J. 2010,
16, 13077−13081. (c) Wang, D.; Zhang, B.; He, C.; Wu, P.; Duan, C.
Chem. Commun. 2010, 46, 4728−4730. (d) Rit, A.; Pape, T.; Hahn, F. E.
J. Am. Chem. Soc. 2010, 132, 4572−4573. (e) Rit, A.; Pape, T.; Hepp, A.;
Hahn, F. E. Organometallics 2011, 30, 334−347.
(6) (a) Boydston, A. J.; Bielawski, C. W. Dalton Trans. 2006,
4073−4077. (b) Williams, K. A.; Boydston, A. J.; Bielawski, C. W. Chem.
Soc. Rev. 2007, 36, 729−744. (c) Neilson, B. M.; Tennyson, A. G.;
Bielawski, C. W. J. Phys. Org. Chem. 2012, 25, 531−543.
(7) (a) Song, Y.ꢀF.; Cronin, L. Angew. Chem., Int. Ed. 2008, 47,
4635−4637. (b) Gadzikwa, T.; Farha, O. K.; Malliakas, C. D.; Kanatzidis,
M. G.; Hupp, J. T.; Nguyen, S. T. J. Am. Chem. Soc. 2009, 131,
13613−13613. (c) Shultz, A. M.; Sarjeant, A. A.; Farha, O. K.; Hupp, J.
T.; Nguyen, S. T. J. Am. Chem. Soc. 2011, 133, 13252−13255. (d) Cohen,
S. M. Chem. Rev. 2012, 112, 970−1000.
(8) (a) Sun, S.ꢀS.; Stern, C. L.; Nguyen, S. T.; Hupp, J. T. J. Am. Chem.
Soc. 2004, 126, 6314−6326. (b) Zheng, Y.ꢀR.; Lan, W.ꢀJ.; Wang, M.;
Cook, T. R.; Stang, P. J. J. Am. Chem. Soc. 2011, 133, 17045−17055. (c)
Chakrabarty, R.; Stang, P. J. J. Am. Chem. Soc. 2012, 134, 14738−14741.
(9) (a) Georgiev, I. G.; MacGillivray, L. R. Chem. Soc. Rev. 2007, 36,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
−Eur. J.
−
Jin, G.ꢀX. Chem.− Eur. J. 2011, 17, 1863−1871. (i) Kole, G. K.; Tan, G.
K.; Vittal, J. J. Cryst. Growth Des. 2012, 12, 326−332. (j) Lu, Z.ꢀZ.; Lee,
C.ꢀC.; Velayudham, M.; Lee, L.ꢀW.; Wu, J.ꢀY.; Kuo, T.ꢀS.; Lu, K.ꢀL.
Chem.− Eur. J. 2012, 18, 15714−15721.
(13) (a) Rit, A.; Pape, T.; Hahn, F. E. Organometallics 2011, 30,
6393−6401. (b) Liu, Q.ꢀX.; Yao, Z.ꢀQ.; Zhao, X.ꢀJ.; Chen, A.ꢀH.; Yang,
X.ꢀQ.; Liu, S.ꢀW.; Wang, X.ꢀG. Organometallics 2011, 30, 3732−3739.
(c) Saito, S.; Saika, M.; Yamasaki, R.; Azumaya, I.; Masu, H.
Organometallics 2011, 30, 1366−1373. (d) Cure, J.; Poteau, R.; Gerber, I.
C.; Gornitzka, H.; Hemmert, C. Organometallics 2012, 31, 619−626. (e)
Gierz, V.; MaichleꢀMössmer, C.; Kunz, D. Organometallics 2012, 31,
739−747.
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