Multidentate pyridyl-based ligands in the coordination-driven self-assembly of palladium metallo-macrocycles

Article abstract of DOI:10.1002/ejoc.201001368

In the current study, a convenient way is presented to synthesize one ditopic and two tetratopic pyridine-based ligands, which are then used to construct metallo-supramolecular polygons. The tetratopic ligands offer two different metal-binding sites, one

Full text of DOI:10.1002/ejoc.201001368

FULL PAPER
DOI: 10.1002/ejoc.201001368
Multidentate Pyridyl-Based Ligands in the Coordination-Driven Self-Assembly
of Palladium Metallo-Macrocycles
Boris Brusilowskij[a] and Christoph A. Schalley*[a]
Keywords: Palladium / Self-assembly / Supramolecular chemistry / Metallo-supramolecular chemistry / Dynamic
combinatorial chemistry
In the current study, a convenient way is presented to synthe-
size one ditopic and two tetratopic pyridine-based ligands,
which are then used to construct metallo-supramolecular
polygons. The tetratopic ligands offer two different metal-
binding sites, one central 2,2Ј-bipyridine, which can act as a
chelate ligand, and two separate pyridine rings, which medi-
ate assembly formation. The three ligands differ with respect
to their conformational flexibility. While a biphenyl core al-
lows the ligand to adjust its conformation as needed, a bipyr-
idine core strongly prefers a divergent arrangement of the
additional pyridine binding sites, but can be fixed in a cisoid
conformation by metal complexation to the bipyridine.
Instead, a phenanthroline core already fixes the pyridinyl-
ethynyl substituents in a cisoid structure without any metal
coordinated to it. Upon mixing each one of the ligands sepa-
rately with the appropriate amount of dpppPdII triflate, dis-
crete self-assembled metallo-macrocycles are formed which
are characterized by 1H and 31P NMR spectroscopy and mass
spectrometry. Mixing all three ligands simultaneously with
the metal complex leads to the formation of a statistical dy-
namic combinatorial library (DCL) of all possible homo- and
heterodimeric metallo-supramolecular assemblies. This
underlines the conformational differences between the three
ligands not to impact significantly on the self-assembly pro-
cess.
Therefore, the three ligands 1–3 (Scheme 1) have been syn-
thesized, two of which (1 and 2) bear an additional chelat-
ing 2,2Ј-bipyridine or phenanthroline binding site, respec-
tively, for metal complexation. The biphenyl ligand may
serve as a control compound. These three ligands differ
with respect to their conformational flexibility: ligand 3 be-
ars a dihedral angle around the central aryl–aryl bond of
about 140° and can easily adjust to the requirements of
metallo-supramolecular assembly formation. Ligand 2 fixes
the two pyridylethynyl substituents in a cisoid arrangement.
Ligand 1, however, prefers the transoid coplanar structure
as shown in Scheme 1, but can rotate into the energetically
Introduction
Metallo-supramolecular chemistry[1] has evolved to a
high degree of sophistication and provides access to a broad
variety of supramolecular architecture such as grids,[2] hel-
icates,[3] polygons,[4] polyhedra and cages,[5] or interlocked
structures,[6] just to name a few. They exhibit remarkable
features when they for example undergo highly selective
self-sorting[7] or when they perform function[8] such as cata-
lyzing reactions in their cavities.[9] Interesting are also archi-
tectures, in which different metal binding sites are incorpo-
rated.[10] Earlier reports introduced 2,2Ј:4,4ЈЈ;4Ј,4ЈЈЈ-quater-
pyridine ligands to generate heterometallic macrocycles by
applying the “complex-as-ligand” approach. This strategy
is based on the formation of a kinetically inert complex of
a ligand with the first metal ion followed by the formation
of metallo-supramolecular macrocycles through coordina-
tion of the remaining binding sites to a kinetically labile
metal ion.[11] In these quaterpyridine-based macrocycles,
the inner cavities are rather small, even though extraction
studies have shown small aromatic molecules to bind inside
the cavities in water by the hydrophobic effect.[12]
The aim of the present study is to extend the cavity size
by inserting ethynylene spacers between the pyridine rings.
[a] Institut für Chemie und Biochemie and Center of
Supramolecular Interactions (CSI Berlin), Freien Universität,
Takustr. 3, 14195 Berlin, Germany
E-mail: christoph@schalley-lab.de
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201001368.
Scheme 1. Ligands and metal centre used in the studies.
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 469
Eur. J. Org. Chem. 2011, 469–477

B. Brusilowskij, C. A. Schalley
FULL PAPER
Scheme 2. Preparation of ligands 1, 2 and 3.
less favorable cisoid structure, if induced by the assembly bridge between the two pyridine rings in phenanthroline li-
formation. Upon metal-ion binding to its 2,2Ј-bipyridine gand 2 necessarily implies a fixed cisoid conformation in-
site, this orientation is again fixed.
stead. The two pyridyl binding sites are consequently ori-
Herein, we report the synthesis of the three ligands 1–3 ented to the same site of the phenanthroline core with an
(Scheme 2) and their self-assembly features when com- N–N distance of the pyridyl nitrogens of 13.19 Å. While 2
plexed to the (dppp)PdII triflate 4. The ancillary dppp Li- is fixed, bipyridine ligand 1 can be converted into a cisoid
gand [dppp = 1,3-bis(diphenylphosphanyl)propane] pro- conformation by metal complexation to the bipyridine site.
tects two coordination sites at the square-planar metal cen- Finally, two conformations exist for ligand 3. In one of
ters and thus dictates the two remaining binding sites to them, the aryl-aryl bond dihedral angle amounts to approx-
complex two ligands in a 90° arrangement. In order to as- imately 139° (conformer 3a). The second conformer 3b be-
sess potential conformational differences influencing the ars a smaller dihedral angle of ca. 40°. Both conformers are
outcome of the assemblies, different ligand mixtures were calculated to be energetically very close to each other (ΔE
subjected to self-assembly experiments. The resulting li- = 0.13 kJ/mol). Likely, the barrier for their mutual intercon-
brary compositions indicate, whether certain isomers are version is not very high. Ligand 3 is thus quite flexible with
energetically unfavorable.
respect to the relative orientation of the two terminal pyr-
idine binding sites and can adapt to different structural
requirements resulting from assembly formation.
Results and Discussion
Synthesis and Molecular Modeling of Ligands 1–3
The synthesis of the two tetratopic ligands 1 and 2 and
the ditopic analogue 3 is shown in Scheme 2. The key step
is the transformation of the dicarbaldehydes 5–7 to the cor-
responding acetylene moieties using Bestmann–Ohira[13]
conditions. This reaction step works with good to excellent
yields and simplifies the syntheses of the ethynyl-substituted
intermediates significantly, in particular in comparison to
an earlier literature-known route[14] describing bipyridine 8.
A second Pd-catalyzed Sonogashira cross-coupling step
concludes the ligand synthesis by attaching the pyridine
rings to the terminal alkynes.
Molecular modeling (MM2 force-field as implemented in
the CaCHE 5.0 program package)[15] was used to obtain
insight into the geometric features of the three ligands 1–3
(Figure 1). In ligand 1, the bipyridine site adopts an almost
coplanar transoid[16] conformation with the two pyridyl sites
pointing away from each other (N–N distance: 18.94 Å).
The corresponding cisoid conformation is predicted by the
simple force field calculation to be higher in energy by
8.4 kJ/mol. Likely, this value is somewhat too low and devi-
ates from the literature value (23.8 kJ/mol).[17] Nevertheless,
Figure 1. MM2-optimized[15] geometries of ligands 1, 2 and 3
shown in ball and stick representation. Lengths give the N–N dis-
the trend is in line with the literature data. The additional tances between the terminal pyridine nitrogen atoms.
470 Eur. J. Org. Chem. 2011, 469–477
www.eurjoc.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Self-Assembly of Palladium Metallo-Macrocycles
Self-Assembly of Metallo-Supramolecular Macrocycles
1843, 1866) and triply charged (m/z = 1179, 1195) ions are
observed, 13 appears in the mass spectra as a singly charged
quasimolecular ion (m/z = 2197). The isotope patterns agree
well with those calculated based on natural abundances.
Larger oligomers have not been found in the ESI mass spec-
tra. Some minor signals correspond to fragments and are
typical for many metallo-supramolecular assemblies.
In order to test whether the three ligands 1–3 assemble
with metal complex 4 into the expected well-defined
metallo-supramolecular macrocycles 11, 12 and 13 (Fig-
ure 2), each of them was stirred with the appropriate
amount of 4 (1:2 ratio for 1 and 2, 1:1 ratio for 3) in CD2Cl2
for 30 min at room temperature. Since (dppp)PdII pyridine
complexes equilibrates quite quickly,[18] the thermodynamic
equilibrium is reached after this time interval. No changes
in the NMR spectra have been observed after longer reac-
tion times.
Figure 2. Cartoon illustration of the formation of three different
metallo-macrocycles 11, 12 and 13 after reacting two tetratopic li-
gands 1, 2 and one ditopic ligand 3 separately with Pd metal centre
4. In all three cases, a ligand concentration of 4.9 mm was used.
In all three cases, the formation of discrete assemblies as
the only products is indeed confirmed by 1H and 31P NMR
spectroscopy and ESI mass spectrometry (Figure 3). In the
1H NMR spectra, only one set of signals is observed which
can be assigned unambiguously by 1H,1H COSY NMR
spectra. The pyHα protons show the expected small down-
field shifts relative to the free ligand, which are indicative
of the coordination to the Pd metal centers. The pyHβ, bi-
pyHα, phenHα, bipyHβ and phenHβ signals, however, shift
to higher field upon coordination to the Pd complex. These
signal shifts can be explained by the shielding effect of the
dppp phenyl groups, in whose anisotropy these protons are
located. In the 31P NMR, two quite sharp signals are ob-
served for each of the assemblies 11 and 12. Both are shifted
to higher field as compared to the free Pd metal complex
4. The signals at 14.89 (for 11) and 15.51 ppm (for 12) can
Figure 3. Partial 1H and 31P NMR spectra of 11 (a), 12 (b) and 13
(c). 1H NMR signals were assigned by 1H,1H COSY NMR experi-
ments. Insets on the left show the experimental and calculated iso-
tope patterns obtained from ESI-MS experiments.
The above-mentioned studies on quaterpyridine com-
be assigned to the P atoms of the (dppp)PdII centers com- plexes[11,12] reported that the 2,2Ј-bipyridine site is the first
plexed to the bidentate bipyridine or phenanthroline sites, one to complex to a given metal center. Afterwards, a sec-
respectively. The other signals at δ = 7.27 ppm for 11 and ond metal ion mediated the formation of the metallo-
7.48 ppm for 12 correspond to the (dppp)PdII coordinated macrocycles. Ligands 1 and 2 in the present study offer sim-
to the terminal pyridine nitrogen atoms. The fact that sing- ilar binding sites and based on the quaterpyridine studies,
lets are observed for all phosphorus atoms in the 31P NMR the coordination of the first (dppp)PdII metal complex to
spectra indicates both P atoms in each metal complex to be ligand 1 or 2 would be expected to occur at the bipyridine.
symmetry equivalent so that we can safely conclude highly Recent studies by Besenyei et al.[10] employing less closely
symmetrical assemblies to form. For 13, only one signal at related Schiff-base-type ligands however revealed the metal
δ = 7.04 ppm appears in the 31P NMR spectrum, support- to first coordinate at the terminal pyridyl group and only
ing the assignments of the 31P NMR signals of the other in a second step to the chelating bis-imine binding site. This
assemblies as discussed above. Electrospray ionization mass prompted us to titrate ligand 1 with metal complex 4 to
spectrometric analyses unambiguously confirm the exis- examine the sequence of binding events for 1 (Figure 4).
tence of the three assemblies. For 11 and 12, doubly (m/z = Upon mixing ligand 1 with 4 in a 1:1 ratio in CD2Cl2 and
Eur. J. Org. Chem. 2011, 469–477
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
471

B. Brusilowskij, C. A. Schalley
FULL PAPER
stirring for 30 min at room temperature, the most signifi- fer into the gas phase, charge repulsion adds to the lower
1
cant signal shifts in the H NMR spectra (again assigned stability and fragmentation occurs. As soon as a second
with the help of COSY NMR spectra) are observed for the metal has bound to the bipyridine site, the conformation of
pyHα and pyHβ protons, while the protons of the bipyridine 1 is fixed in a cisoid structure which can again nicely as-
binding site do not shift much. Similarly, in the 31P NMR semble. Consequently, 11 can easily be ionized as intact
spectrum, a signal appears at the position which was as- macrocycle.
signed to a (dppp)PdII complexed to two pyridines. The sec-
The fact that the first coordination occurs at the pyridine
ond signal for the bipyridine-coordinated metal complex is site implies that a 2:2 metallo-supramolecular macrocycle
missing completely. Again, the signals in the 31P NMR can be generated which can be switched in conformation by
spectra indicate a high symmetry of the complex which is metal coordination to the two bipyridine sites: Molecular
presumably the 2:2 metallo-macrocycle 14. Upon addition modeling predicts a chair-like conformation as the most
of a second equivalent of 4, also the bipyridine protons un- stable structure for 14 as well as its biphenyl analogue 13
dergo significant shifts and the second signal in the 31P (Figure 5, top). In this analogy to a cyclohexane ring, the
NMR assigned to the bipyridine-coordinated metal center cyclohexane carbon atoms are identified with the two metal
becomes visible. From these NMR results, we can conclude centers and the two aromatic rings of the two bipyridine/
that the (dppp)PdII metal center first complexes to the pyr- biphenyl aromatic rings. In this chair-like conformation,
idines and only in a second step forms complexes with the minimal torsional strain builds up along the aryl-aryl bonds
bipyridine site.
for the biphenyl ligands 3. Ligand 1 however has already
undergone a conformational change from the coplanar
transoid structure to a structure with a NCCN dihedral an-
gle of 143°. Upon coordination of metal centers to the two
bipyridine sites in 14, a second conformational change oc-
curs. The bipyridine needs to convert into the cisoid form
and the conformation of the assembly must thus change
into a boat-like conformation as realized also for the phen-
anthroline complex 12 (Figure 5, bottom).
Figure 5. A comparison of geometry-optimized structures (MM2
force field)[15] of 13 and 14 in their chair-like conformations (top)
and of 11 and 12 in their boat-like conformations. For clarity, the
dppp ligands were removed after geometry optimization. The metal
ions are depicted in space-filling representation.
Figure 4. Partial 1H and 31P NMR spectra of a) ligand 1, b) 1
(4.9 mm) mixed with 4 in a 1:1 ratio, and c) 1 (4.9 mm) and 4 mixed
in a 1:2 ratio (asterisks * indicate the formation of a 3:3 metallo-
macrocycle).
In order to investigate, whether the conformational pref-
ESI mass spectra of 14 obtained under conditions that erences of the ligands would affect the formation of the
were also used for the characterization of macrocycles 11– macrocycles, we mixed ligands 1–3 in all possible binary
13 only exhibit signals for 1:1 complexes, whose symmetry combinations with the appropriate amount of 4 in CD2Cl2.
is not in agreement with the NMR spectroscopic data. Con- In a first experiment, 1, 3 and 4 were thus mixed in a 1:1:3
1
sequently, we ascribe these signals to fragments. The appar- ratio. The H and 31P NMR spectra are shown in Figure 6
ent higher tendency of 14 to fragment upon ionization may (bottom trace). Similarly, 2, 3 and 4 (1:1:3) and 1, 2 and 4
be rationalized as follows: Ligand 1 prefers a coplanar (1:1:4) were mixed in a second and third experiment (Fig-
transoid conformation. Upon assembly formation, it must ure 6, two center traces). Finally, all ligands 1, 2, and 3 were
fold into a less favorable bent conformation higher in en- treated with 4 in a 1:1:1:5 ratio (Figure 6, top trace). Parts
ergy. While this is easily accomplished for ligand 3, which of the ESI mass spectra obtained from the last experiment
thus forms more stable ESI-MS-detectable metallo-macro- are shown in Figure 7. Our idea was that no significant de-
cycles 13, assembly 14 suffers from some strain. After trans- viations from statistical mixtures of the homo- and hetero-
472
www.eurjoc.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2011, 469–477

Self-Assembly of Palladium Metallo-Macrocycles
1
dimeric macrocycles would be observed when all ligands biguously assigned. The H and 31P NMR spectra thus re-
can adapt to the geometric requirements of the assemblies. veal the formation of statistically distributed small dynamic
Instead, if strain would build during the assembly forma- libraries of discrete metallo-macrocyles to form. All pos-
tion due to the conformational preferences of any one of sible homo- and heterodimers are present in the mixtures.
the ligands, one would expect certain heterodimers to be Mass spectrometric experiments with the most complex
energetically disfavored. Consequently, the formation of mixture containing all three ligands and complex 4 also
small dynamic libraries would provide some insight into the supports the formation of a statistical mixture of 11, 12, 13,
importance of conformational aspects for the assembly for- 15, 16, and 17 (Figure 7). Consequently, we can conclude
mation.
that the ligands 1 and 3 can adapt to structural require-
ments occurring during the assembly process. Ligand 2 of
course is fixed in its conformation, but since the other li-
gands can adjust their geometry this does not pose any
problems for the assembly process.
Conclusions
Besides making use of the quite efficiently working Best-
mann–Ohira reaction as a key step in the synthesis of the
ligands under study here, the data obtained shows discrete
2:2 and 2:4 metallo-macrocycles to form from 1–3 when
assembled with metal complex 4. A remarkable finding is
the order of coordination steps of 4 to ligand 1, which fol-
lows a reversed order than the literature data published on
very similar ligands. With the ethynylene spacers incorpo-
rated, the first two (dppp)PdII complexes coordinate to the
pyridine binding sites forming a 2:2 macrocycle. In the sec-
ond step, the bipyridine sites are occupied, when a second
equivalent of (dppp)PdII triflate is added. These two steps
proceed well separated from each other as becomes clear
from the NMR spectra, which hardly show any coordina-
tion to the bipyridine site after the addition of the first
equivalent of 4. Mixing experiments lead to the formation
of statistical mixtures of all possible assemblies and thus
underline the different conformational preferences of the li-
gands not to have visible effects on the self-assembly pro-
cess.
Figure 6. Partial 1H and 31P NMR spectra of a small DCL of three
to six discrete metallo-supramolecular assemblies 11, 12, 13, 15, 16
and 17 ([4] = 7.4 mm).
The interesting coordination sequence can be used to
construct heterometallic complexes in the future, maybe
even with metals which do not form kinetically inert com-
plexes. It will certainly be interesting to study a hetero-
metallic self-sorting during the assembly of metallo-supra-
molecular macrocycles from the ligands presented here.
Furthermore, the macrocycles under study have somewhat
larger cavities which may be useful for host-guest chemistry.
Through the different conformational features and the pos-
sibility to attach additional metal complexes to the bipyr-
idine sites, it should be feasible to tune the host properties
to some extent and thus to influence the host-guest proper-
ties.
Figure 7. Partial ESI mass spectra (top) and calculated isotopic
distributions (bottom) of a mixture of all three ligands 1, 2 and 3
with Pd complex 4 (1:1:1:5) sprayed from a DCM/acetone (1:1); [4]
= 98 μm. The spectrum contains signals for all expected metallo-
macrocycles 11, 12, 13, 15, 16 and 17 (asterisks * denote differences
between experimental and calculated patterns can be explained by
superposition with typical singly-charged fragment ions).
Experimental Section
General Remarks: All chemicals were of reagent grade quality and
used as obtained from commercial suppliers without further purifi-
cation. Solvents were used as received or – if necessary – dried
with 4 Å molecular sieve. 2,2Ј-Bipyridine-4,4Ј-dicarbaldehyde (5) is
1
With the help of H,1H COSY NMR spectra, the pyHα
signals of all macrocycles can be assigned (Supporting In-
formation). Similarly, all 31P NMR signals for the (dppp)-
PdII complexed to the bipyridine binding site can be unam- commercially available at HetCat Product List. Pd(dppp)OTf2,[19]
Eur. J. Org. Chem. 2011, 469–477
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
473

B. Brusilowskij, C. A. Schalley
FULL PAPER
1,1Ј-(1,10-phenanthroline-4,7-diyl)diethanone (6),[20] biphenyl-3,3Ј-
chromatography (silica gel, mobile phase: hexane); yield 60 mg,
dicarbaldehyde (7),[21] were prepared as described in the literature.
63%. 1H NMR (400 MHz, CD2Cl2): δ = 3.16 (s, 2 H, CϵH1), 7.43
1
3
3
4
1H, 13C NMR spectra of ligands 1–3, H,1H COSY NMR spectra (t, J = 7.7 Hz, 2 H, ArH3), 7.51 (dt, J = 7.7, J = 1.4 Hz, 2 H,
of metallo-macrocycles 11–13 and the DCL of 11–13 and 15–17
are provided in the Supporting Information
ArH4), 7.59 (dt, 3J = 7.8, 4J = 1.3 Hz, 2 H, ArH3), 7.74 (t, 4J =
1.4 Hz, 2 H, ArH5) ppm. 13C NMR (175 MHz, CD2Cl2): δ = 78.00,
83.84 (CϵCH), 128.15, 129.54, 131.26, 131.26 (CH), 123.25, 140.90
(Cq) ppm. MS (EI, 80 eV, 200 °C): m/z (%) = 202.1 (100)
[M + H]+, 99.8 (8) [M – C8H6]+, 72.1 (3) [M – C10H10]+, 46.1 (1)
[M – C12H12]+.
Instrumentation and Methods: 1H,31P and 1H,1H COSY NMR
spectra were recorded with Jeol ECX-400, Bruker AMX 500 or AV
700 instruments. All chemical shifts are reported in ppm with sol-
vent signals taken as internal standards; coupling constants are in
Hz. Silica gel for flash chromatography was Fluka Analytic 60. The
electrospray-ionization Fourier-transform ion-cyclotron-resonance
(ESI-FTICR) mass spectrometric experiments were performed with
a Varian/IonSpec QFT-7 FTICR mass spectrometer equipped with
a superconducting 7 Tesla magnet and a micromass Z-spray ESI
ion source utilizing a stainless steel capillary with a 0.65 mm inner
diameter. The sample solutions were introduced into the source
with a syringe pump (Harvard Apparatus) at a flow rate of ca.
4.0 μLmin–1. Parameters were adjusted as follows: source tempera-
ture: 45 °C; temperature of desolvation gas: 45 °C; parameters for
capillary voltage, sample and extractor cone voltages are optimized
for maximum intensities and minimal fragmentation. No nebulizer
gas was used for the experiments. The ions were accumulated in
the instrument’s hexapole for 2.5 to 4 s. Next, the ions were trans-
ferred into the FTICR analyzer cell by a quadrupole ion guide.
The FTICR cell was operated at pressures below 10–9 mbar, and
the ions detected by a standard excitation and detection sequence.
For each measurement, 2 to 4 scans were averaged to improve the
signal-to-noise ratio.
4,4Ј-Bis(pyridine-4-ylethynyl)-2,2Ј-bipyridine (1): 4,4Ј-Diethynyl-
2,2Ј-bipyridine (80 mg, 0.38 mmol) and 4-iodopyridine (176 mg,
0.86 mmol) were dissolved under argon atmosphere in 4 mL DMF.
After the addition of triethylamine (2 mL), PPh3 (19.8 mg,
0.08 mmol), CuI (7.2 mg, 0.04 mmol) and Pd(PPh3)2Cl2 (27.48 mg,
0.04 mmol), the reaction mixture was stirred for 12 h at room temp.
KCN (1.2 mg, 0.02 mmol) was added to the reactions mixture and
the solvent was evaporated under reduced pressure. The crude
product was purified by column chromatography (silica gel, mobile
phase: CH2Cl2/MeOH = 100:4); yield 83 mg, 58%. 1H NMR
(400 MHz, CD2Cl2): δ = 7.43 (AAЈXXЈ, J = 6.0 Hz, 4 H, pyHβ),
3
4
7.46 (dd, J = 6.5, J = 1.6 Hz, 2 H, bipyHβ), 8.59–8.58 (br., 2 H,
bipyHδ), 8.62 (AAЈXXЈ, J = 6.0 Hz, 4 H, pyHα) 8.69 (d, 3J =
5.0 Hz, 2 H, bipyHα) ppm. 13C NMR (176 MHz, CD2Cl2): δ =
91.15, 91.20 (CϵC), 123.66, 126.13, 126.30, 150.02, 150.59 (CH),
130.66, 131.18, 156.28 (Cq) ppm. ESI-MS: m/z (%) = 359.1 (100)
[M + H+]. HRMS (ESI) calculated mass 359.1291 (C24H14N4 [M
+ H]+); found 359.1279.
4,7-Bis(pyridin-4-ylethynyl)-1,10-phenanthroline (2): 4,7-Diethynyl-
1,10-phenanthroline (45 mg, 0.20 mmol) and 4-iodopyridine
(93 mg, 0.45 mmol) were dissolved under argon atmosphere in
5 mL DMF. After the addition of triethylamine (2 mL), PPh3
(5.6 mg, 0.06 mmol), CuI (10.4 mg, 0.04 mmol) and Pd(PPh3)2Cl2
(13.9 mg, 0.02 mmol), the reaction mixture was stirred for 12 h at
room temp. KCN (0.65 mg, 0.01 mmol) was added to the reactions
mixture and the solvent was evaporated under reduced pressure.
The crude product was purified by column chromatography (silica
4,4Ј-Diethynyl-2,2Ј-bipyridine (8):[22] 2,2Ј-Bipyridine-4,4Ј-dicarbal-
dehyde (200 mg, 0.94 mmol) and K2CO3 (520 mg, 1.88 mmol) were
dissolved in 15 mL MeOH. After the addition of dimethyl (1-diazo-
2-oxopropyl)phosphonate (434 mg, 2.26 mol) the reaction mixture
was stirred for 30 min at room temp. The solvent was evaporated
under reduced pressure and the crude product was purified by col-
umn chromatography (silica gel, mobile phase: CH2Cl2/MeOH =
97:3); yield 180.0 mg, 94%. 1H NMR (400 MHz, [D6]THF): δ =
3.99 (s, 2 H, CϵH1), 7.40 (dd, J = 6.5, J = 1.5 Hz, 2 H, Ar-H2),
8.51 (d, 4J = 1.3 Hz, 2 H, ArH4), 8.63 (d, 3J = 5.79 Hz, 2 H, ArH3)
ppm. 13C NMR (100 MHz, [D6]THF): δ = 82.14, 83.93 (CϵCH),
124.46, 127.12, 150.47 (CH), 132.48, 156.63 (Cq) ppm. ESI-MS:
m/z (%) = 205.1 (100) [M + H]+. HRMS (ESI) calculated mass
205.0760 (C14H8N2 [M + H]+); found 205.0776.
3
4
1
gel, mobile phase: CH2Cl2/MeOH = 100:4); yield 24 mg, 32%. H
NMR (400 MHz, CD2Cl2): δ = 7.56 (AAЈXXЈ, J = 6.0 Hz, 4 H,
pyHβ), 7.85 (d, 3J = 4.2 Hz, 2 H, phenHβ), 8.46 (s, 2 H, ArH5),
8.70 (AAЈXXЈ, J = 6.0 Hz, 4 H, pyHβ) 9.16–9.17 (br. s, 2 H,
phenHα) ppm. 13C NMR (175 MHz, CD2Cl2): δ = 89.16, 96.22
(CϵCH), 125.62, 126.10, 126.47, 150.41, 150.70 (CH), 128.79,
129.12, 130.48, 146.91 (Cq) ppm. ESI-MS: m/z (%) = 383.1 (100)
[M + H+]. HRMS (ESI) calculated mass 383.1291 (C26H15N4
[M + H]+); found 383.1305.
4,7-Diethynyl-1,10-phenanthroline (9): 1,10-Phenanthroline-4,7-di-
carbaldehyde (98.2 mg, 0.42 mmol) and K2CO3 (231.2 mg,
1.68 mmol) were dissolved in 15 mL MeOH. After the addition of
dimethyl (1-diazo-2-oxopropyl)phosphonate (193.7 mg, 1.10 mmol)
the reaction mixture was stirred for 2 h at room temp. The solvent
was evaporated under reduced pressure and the crude product was
purified by column chromatography (silica gel, mobile phase:
CH2Cl2/MeOH = 97:3); yield 56 mg, 58%. 1H NMR (400 MHz,
CDCl3): δ = 3.74 (s, 2 H, CϵH1), 7.78 (d, 3J = 7.2 Hz, 2 H, ArH2),
7.51 (s, 2 H, ArH4), 9.17 (d, 3J = 7.2 Hz, 2 H, ArH3) ppm. 13C
NMR (100 MHz, CD2Cl2): δ = 79.11, 86.96 (CϵCH), 124.96,
149.73 (CH), 126.36, 128.57, 128.74, 146.90 (Cq) ppm. ESI-MS:
m/z (%) = 229.0 (100) [M + H]+. HRMS (ESI) calculated mass
229.0760 (C16H9N2 [M + H]+); found 229.0760.
3,3Ј-Bis(pyridin-4-ylethynyl)biphenyl (3): 3,3Ј-Diethylnylbiphenyl
(60 mg, 0.30 mmol) and 4-iodopyridine (139.8 mg, 0.68 mmol)
were dissolved under argon atmosphere in 5 mL DMF. After the
addition of triethylamine (2 mL), PPh3 (15.6 mg, 0.06 mmol), CuI
(8.5 mg, 0.04 mmol) and Pd(PPh3)2Cl2 (20.8 mg, 0.03 mmol), the
reaction mixture was stirred for 12 h at r.t and the solvent was
evaporated under reduced pressure. The crude product was purified
by column chromatography (silica gel, mobile phase: CH2Cl2
Ǟ
CH2Cl2/EE = 1:1); yield 48 mg, 45%. 1H NMR (400 MHz,
3
CD2Cl2): δ = 7.42 (AAЈXXЈ, J = 4.4 Hz, 4 H, pyHβ), 7.51 (t, J =
3
7.6 Hz, 2 H, ArH4), 7.59 (br. t, J = 7.6 Hz, 2 H, ArH5), 7.63 (br.
3,3Ј-Diethylnylbiphenyl (10): Biphenyl-3,3Ј-dicarbaldehyde (100 mg,
0.48 mmol) and K2CO3 (138 mg, 1.90 mmol) were dissolved in
15 mL MeOH. After the addition of dimethyl (1-diazo-2-oxopro-
pyl)phosphonate (219 mg, 1.14 mmol) the reaction mixture was
stirred for 2 h at room temp. The solvent was evaporated under
reduced pressure and the crude product was purified by column
t, 3J = 7.8 Hz, 2 H, ArH3), 7.84 (s, ArH6), 8.60 (AAЈXXЈ, J =
4.4 Hz, 4 H, pyHα) ppm. 13C NMR (125 MHz, CD2Cl2): δ = 87.37,
93.95 (CϵCH), 125.81, 128.39, 129.61, 130.87, 131.62 150.46 (CH),
130.87 123.22, 141.03 (Cq) ppm. ESI-MS: m/z (%) = 357.1 (100)
[M + H]+. HRMS (ESI) calculated mass 357.1386 (C26H17N2 [M
+ H]+); found 357.1385.
474
www.eurjoc.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2011, 469–477

Self-Assembly of Palladium Metallo-Macrocycles
Metallo-Macrocycle 11: Ligand (0.44 mg, 0.0012 mmol) in 7.89–7.98 (m, 24 H, Hdppp), 8.33 [s, 2 H, ArH5phen(16)], 8.34 [s, 4 H,
1
CD2Cl2 (0.25 mL) was added to a suspension of Pd(dppp)OTf2 4
(2.00 mg, 0.0024 mmol) in CD2Cl2 (0.25 mL). The mixture was
stirred at room temp. for 30 min. The yellowish solution was trans-
ferred into an NMR tube for analysis. 1H NMR (400 MHz,
ArH5phen(12)], 8.86–8.92 [m, 12 H, py3Hα(13)(16)], 8.95–9.10 [m, 12
H, py2Hα(12)(16)] ppm. 31P NMR (162 MHz, CD2Cl2): δ = 6.78 (s),
6.99 (s), 7.06 (s), 7.30 (s) 7.43 (s) 14.83 (s), 15.51 (s) ppm. ESI-MS:
m/z (%) = 1024.1 (100) [13 – 2OTf]2+, 1195.0 (80) [12 – 3OTf]3+
,
CD2Cl2): δ = 2.25–2.29 (m, 8 H, Hdppp), 2.67–2.70 (br. s, 8 H, 1445.6 (10) [16 – 2OTf]2+, 2197.2 (5) [13 – OTf]+.
Hdppp), 3.18–3.20 (br. s, 8 H, Hdppp), 6.94 (dd, 3J = 7.5, 4J = 1.5 Hz,
Ligand 1 (0.44 mg, 0.0012 mmol), ligand 3 (0.44 mg, 0.0012 mmol)
were dissolved in CD2Cl2 (0.25 mL) and simultaneously added to
a suspension of Pd(dppp)OTf2 4 (3.00 mg, 0.0037 mmol) in CD2Cl2
(0.25 mL). The mixture was stirred at room temp. for 24 h. The
yellowish solution was transferred into an NMR tube for analysis.
1H NMR (400 MHz, CD2Cl2): δ = 2.28–2.32 (m, 18 H, Hdppp),
2.78–2.81 (m, 16 H, Hdppp), 3.21–3.24 (m, 24 H, Hdppp), 6.96 [two
overlapped dd, 3J = 6.0, 4J = 1.6 Hz, 6 H, bipyHβ (11)(15)], 7.10–
7.13 [br. d, 12 H, py3Hβ(13)(15)], 7.21–7.24 [m, 12 H, py1Hβ(11)(15)],
3
4 H, bipyHβ), 7.21 (d, J = 5.5 Hz, 8 H, pyHβ), 7.34–7.70 (m, 64H
+ 4 H, Hdppp, bipyHα), 7.88 (m, 16 H, Hdppp), 8.33–8.36 (br., 4 H,
bipyHδ), 8.94 (d, 3J = 5.6 Hz, 8 H, pyHα) ppm. 31P NMR
(162 MHz, CD2Cl2): δ = 7.27 (s), 14.89 (s) ppm. ESI-MS: m/z =
1843.0 (100) [11 – 2OTf]2+, 1179.0 (55) [11 – 3OTf]3+
.
Metallo-Macrocycle 12: Ligand
2 (0.44 mg, 0.0012 mmol) in
CD2Cl2 (0.25 mL) was added to a suspension of Pd(dppp)OTf2 4
(2.00 mg, 0.0024 mmol) in CD2Cl2 (0.25 mL). The mixture was
stirred at room temp. for 30 min. The yellowish solution was trans-
ferred into an NMR tube for analysis. 1H NMR (400 MHz,
CD2Cl2): δ = 2.26–2.33 (m, 8 H, Hdppp), 2.68–2.71 (br. s, 8 H,
Hdppp), 3.22–3.24 (br. s, 8 H, Hdppp), 7.32–7.80 (m, 8 H, 4H, 64 H,
pyHβ, phenHβ, Hdppp), 7.77–7.79 (m, 4 H, phenHα) 7.98 (m, 16 H,
7.35–7.70 [m, 156 H, 6H, 6H, 6H, 6H, 6 H, Hdppp, bipyHα(11)(15)
,
ArH3(13)(15), ArH4(13)(15), ArH5(13)(15), ArH6(13)(15)], 7.88–7.94 (m, 24
H, Hdppp), 8.26–8.28 [br. s, 2 H, bipyHδ(15)], 8.37–8.39 [br. s, 4 H,
bipyHδ(11)], 8.86–8.89 [m, 12 H, py3Hα(13)(15)], 8.95–8.98 [m, 8 H, 4
H, py1Hα(11), py1Hα(15)] ppm. 31P NMR (202 MHz, CD2Cl2): δ =
7.01 (s), 7.17 (s), 7. 26 (s), 7.42 (s), 7.56 (s), 14.53 (s), 14.88 (s) ppm.
ESI-MS: m/z (%) = 1843.1 (100) [11 – 2OTf2+], 1179.0 (25) [11 –
3OTf3+], 1433.6 (10) [15 – 2OTf2+]. 2197.2 (5) [13 – OTf+].
3
Hdppp), 8.35 (s, 4 H, ArH5), 9.08 (d, J = 5.2 Hz, 8 H, pyHα) ppm.
31P NMR (162 MHz, CD2Cl2): δ = 7.48 (s), 15.51 (s) ppm. ESI-
MS: m/z = 1866.0 (100) [12 – 2OTf]2+, 1195.0 (20) [12 – 3OTf]3+
.
Ligand
1
(0.26 mg, 0.00073 mmol), ligand
2
(0.26 mg,
Metallo-Supramolecular Assembly 13: Ligand
3
(0.87 mg,
0.00073 mmol) and ligand 3 (0.28 mg, 0.0073 mmol) were dissolved
in CD2Cl2 (0.25 mL) and simultaneously added to a suspension of
Pd(dppp)OTf2 4 (3.00 mg, 0.0037 mmol) in CD2Cl2 (0.25 mL). The
mixture was stirred at room temp. for 24 h. The yellowish-green
0.0024 mmol) in CD2Cl2 (0.25 mL) was added to a suspension of
Pd(dppp)OTf2 4 (2.00 mg, 0.0024 mmol) in CD2Cl2 (0.25 mL). The
mixture was stirred at room temp. for 30 min. The yellowish solu-
tion was transferred into an NMR tube for analysis. 1H NMR
(500 MHz, CD2Cl2): δ = 2.25–2.34 (m, 4 H, Hdppp), 3.21–3.23 (br.
1
solution was transferred into an NMR tube for analysis. H NMR
3
(500 MHz, CD2Cl2): δ = 2.31–2.34 (m, 46 H, Hdppp), 2.73–2.76
(m, 34 H, Hdppp), 3.22–3.25 (m, 40 H, Hdppp), 6.93–6.96 [m, 8 H,
bipyHβ(11)(15)(17)], 7.11–7.15 [m, 16 H, py3Hβ(13)(15)(16)], 7.21–7.26
[m, 16 H, py1Hβ(11)(15)(17)], 7.34–7.75 [m, 16 H, 270H, 10H, 8H,
s, 8 H, Hdppp), 7.12 (d, J = 6.4 Hz, 8 H, pyHβ), 7.34–7.70 (m, 20
H, 4H, 4 H, Hdppp, ArH4, ArH5), 7.68–7.70 (m, 20 H, 4 H, Hdppp
,
ArH6), 8.87 (d, 3J = 8.1 Hz, 8 H, pyHα) ppm. 31P NMR (162 MHz,
CD2Cl2):
δ = 7.04 (s) ppm. ESI-MS: m/z = 2197.2 (100)
[13-OTf]+.
8H, 8 H, py2Hβ(12)(16)(17), Hdppp, ArH3(13)(15)(16), ArH4(13)(15)(16)
,
ArH5(13)(15)(16), ArH6(13)(15)(16)], 7.78–7.82 [m, 8 H, phenHα(12)(16)(17)],
7.88–7-92 (m, 30 H, Hdppp), 7.96–8.00 (m, 30 H, Hdppp), 8.26–8.28
[br. s, 2 H, bipyHδ(15)], 8.29–8.30 [br. s, 2 H, bipyHδ(17)], 8.33 [s, 2
H, phenH5(16)], 8.35 [s, 2 H, phenH5(17)], 8.37–8.39 [br. s, 4 H, 4 H,
Synthesis of a Dynamic Combinatorial Library (DCL) of 2-D
Metallo-Supramolecular Assemblies: Ligand (0.44 mg,
1
0.0012 mmol), ligand 2 (0.47 mg, 0.0012 mmol) were dissolved in
CD2Cl2 (0.25 mL) and simultaneously added to a suspension of
Pd(dppp)OTf2 4 (4.00 mg, 0.0049 mmol) in CD2Cl2 (0.25 mL). The
mixture was stirred at room temp. for 24 h. The yellowish-green
solution was transferred into an NMR tube for analysis. 1H NMR
(500 MHz, CD2Cl2): δ = 2.32–2.36 (m, 28 H, Hdppp), 2.73–2.75
(m, 20 H, Hdppp), 3.23–3.25 (m, 24 H, Hdppp), 6.93–6.96 [m, 6 H,
bipyHβ(11)(17)], 7.21–7.25 [m, 12 H, py1Hβ(11)(17)], 7.34–7.70 [m, 12
H, 192H, 6 H, py2Hβ(11)(17), Hdppp, phenHβ(12)(17)], 7.78–7.82 [m, 6
H, phenHα(12)(17)], 7.88–7-92 (m, 24 H, Hdppp) 7.93–7.98 (m, 24 H,
Hdppp), 8.26–8.30 [br., 2 H, bipyHδ(17)], 8.36 [s, 4 H, ArH5(17)], 8.37–
8.39 [br., 4 H, 4 H, ArH5(12), bipyHδ(11)], 8.97–9.00 [m, 8 H, 4 H,
py1Hα(11), py1Hα(17)], 9.05 [m, 8 H, 4 H, py2Hα(11), py2Hα(17)] ppm.
31P NMR (202 MHz, CD2Cl2): δ = 7.38 (s), 7.42 (s), 7.49 (s), 7.54
(s), 7.61 (s) ppm. ESI-MS: m/z = 1842.6 (18) [11 – 2OTf]2+, 1855.0
phenH5(12), bipyHδ(11)], 8.89–9.10 [m, 48 H, py1py2py3Hα(11)(12)(13)
]
ppm. 31P NMR (202 MHz, CD2Cl2): δ = 6.96 (s), 7.12 (s) 7.20 (s),
7.34 (s), 7.39 (s), 7.45 (s), 7.51 (s), 7.57(s), 14.48 (s), 14.80 (s), 14.88
(s), 15.01 (s), 15.43 (s), 15.50 (s) ppm. ESI-MS: m/z (%) = 1024.1
(100) [13 – 2OTf2+], 1179.0 (10) [11 – 3OTf3+],1187.0 (80) [17 –
3OTf3+], 1195.0 (25) [12 – 3OTf3+], 1433.6 (5) [15 – 2OTf2+], 1445.6
(5) [16 – 2OTf2+], 1842.6 (8) [11 – 2OTf2+], 1855.0 (5) [17 – 2OTf2+],
1866.5 (3) [12 – 2OTf2+].
Supporting Information (see also the footnote on the first page of
this article): 1H and 13C NMR spectra of ligands 1–3 and H,H-
COSY NMR spectra of the metallo-macrocycles.
Acknowledgments
(100) [17 – 2OTf]2+, 1866.5 (25) [12 – 2OTf]2+
.
This work was supported by the Deutsche Forschungsgemeinschaft
(DFG) (SFB 765, Multivalency) and the Fonds der Chemischen
Industrie (FCI). We gratefully acknowledge Dr. Huan Cheng for
his helpful suggestion to synthesize ligand 1–3 utilizing the Best-
mann–Ohira reaction.
Ligand 2 (0.44 mg, 0.0012 mmol), ligand 3 (0.47 mg, 0.0012 mmol)
were dissolved in CD2Cl2 (0.25 mL) and simultaneously added to
a suspension of Pd(dppp)OTf2 4 (3.00 mg, 0.0037 mmol) in CD2Cl2
(0.25 mL). The mixture was stirred at room temp. for 24 h. The
yellowish-green solution was transferred into an NMR tube for
analysis. 1H NMR (400 MHz, CD2Cl2): δ = 2.28–2.31 (m, 18 H,
Hdppp), 2.75–2.77 (m, 16 H, Hdppp), 3.21–3.24 (m, 24 H, Hdppp),
7.12–7.14 [m, 12 H, py3Hβ (13)(16)], 7.30–7.70 [m, 12 H, 156H, 6H,
[1] For a selection of recently published reviews, see: a) S. Lein-
inger, B. Olenyuk, P. J. Stang, Chem. Rev. 2000, 100, 853–908;
b) B. J. Holliday, C. A. Mirkin, Angew. Chem. Int. Ed. 2001,
40, 2022–2043; c) C. H. M. Amijs, G. P. M. Klink, G. Koten,
6H, 6H,
6 H, py2Hβ(12)(16), Hdppp, ArH3(13)(16), ArH4(13)(16),
ArH5biaryl(13)(16), ArH6(13)(16)], 7.78–7.82 [m, 6 H, phenHα(12)(16)],
Eur. J. Org. Chem. 2011, 469–477
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
475

B. Brusilowskij, C. A. Schalley
FULL PAPER
Dalton Trans. 2006, 308–327; d) C. R. K. Glasson, L. F. Lin-
doy, G. V. Meehana, Coord. Chem. Rev. 2008, 252, 940–963; e)
A. Kumara, S.-S. Suna, A. J. Lees, Coord. Chem. Rev. 2008,
252, 922–939; f) P. J. Lusby, Annu. Rep. Prog. Chem. Sect. A:
Inorg. Chem. 2009, 105, 323–347; g) C. Piguet, Chem. Commun.
2010, 46, 6209–6231.
Lett. 2006, 8, 3991–3994; h) D. K. Chand, K. Biradha, M. Ka-
wano, S. Sakamoto, K. Yamaguchi, M. Fujita, Chem. Asian J.
2006, 1, 82–90; i) H. B. Yang, K. Ghosh, B. H. Northrop, P. J.
Stang, Org. Lett. 2007, 9, 1561–1564; j) K. Ono, M. Yoshizawa,
T. Kato, K. Watanabe, M. Fujita, Angew. Chem. Int. Ed. 2007,
46, 1803–1806; k) J. Vacek, D. C. Caskey, D. Horinek, R. K.
Shoemaker, P. J. Stang, J. Michl, J. Am. Chem. Soc. 2008, 130,
7629–7638; l) Y. R. Zheng, H. B. Yang, B. H. Northrop, K.
Ghosh, P. J. Stang, Inorg. Chem. 2008, 47, 4706–4711; m) D. J.
Tranchemontagne, Z. Ni, M. O. Keeffe, O. M. Yaghi, Angew.
Chem. Int. Ed. 2008, 47, 5136–5147; n) S. J. Dalgarno, N. P.
Power, J. L. Atwood, Coord. Chem. Rev. 2008, 252, 825–841; o)
M. J. Prakash, M. S. Lah, Chem. Commun. 2009, 3326–3341.
a) Molecular Catenanes, Rotaxanes and Knots (Eds.: J.-P. Sauv-
age, C. O. Dietrich-Buchecker), Wiley-VCH, Weinheim, Ger-
many, 1999; b) M. Fujita, Acc. Chem. Res. 1999, 32, 53–61;
c) A. Rang, C. A. Schalley in: Encyclopedia of Supramolecular
Chemistry (Eds.: J. L. Atwood, J. W. Steed); Dekker, New York,
2004, p. 206–213; d) M. S. Vickers, P. D. Beer, Chem. Soc. Rev.
2007, 36, 211–225; e) J. F. Stoddart, H. M. Colquhoun, Tetra-
hedron 2008, 64, 8231–8263; f) J. F. Stoddart, Chem. Soc. Rev.
2009, 38, 1521–1529; g) J. F. Stoddart, Chem. Soc. Rev. 2009,
38, 1802–1820.
a) D. L. Caulder, K. N. Raymond, Angew. Chem. Int. Ed. Engl.
1997, 36, 1439–1442; b) E. J. Enemark, T. D. P. Stack, Angew.
Chem. Int. Ed. 1998, 37, 932–935; c) M. Fujita, N. Fujita, K.
Ogura, K. Yamaguchi, Nature 1999, 400, 52–55; d) S. Lein-
inger, B. Olenyuk, P. J. Stang, Chem. Rev. 2000, 100, 853–908;
e) G. F. Swiegers, T. J. Malefetse, Chem. Rev. 2000, 100, 3483–
3537; f) R. Pinalli, V. Cristini, V. Sottili, S. Geremia, M. Cam-
pagnolo, A. Caneschi, E. Dalcanale, J. Am. Chem. Soc. 2004,
126, 6516–6517; g) C. Addicott, N. Das, P. J. Stang, Inorg.
Chem. 2004, 43, 5335–5338; h) T. Kamada, N. Aratani, T.
Ikeda, N. Shibata, Y. Higuchi, A. Wakamiya, S. Yamaguchi,
K. S. Kim, Z. S. Yoon, D. Kim, A. Osuka, J. Am. Chem. Soc.
2006, 128, 7670–7678; i) Y.-M. Legrand, A. Lee, M. Barboiu,
Inorg. Chem. 2007, 46, 9540–9547; j) S. Ghosh, D. R. Turner,
S. R. Batten, P. S. Mukherjee, Dalton Trans. 2007, 1869–1871;
k) E. Zangrando, M. Casanova, E. Alessio, Chem. Rev. 2008,
108, 4979–5013; l) A. Rang, M. Nieger, M. Engeser, A. Lützen,
C. A. Schalley, Chem. Commun. 2008, 4789–4791; m) Y.-R.
Zheng, H.-B. Yang, B. H. Northrop, K. Ghosh, P. J. Stang, In-
org. Chem. 2008, 47, 4706–4711; n) B. H. Northrop, H.-B.
Yang, P. J. Stang, Inorg. Chem. 2008, 47, 11257–11268; o) B. H.
Northrop, H.-B. Yang, P. Stang, Chem. Commun. 2008, 5896–
5908; p) M. Schmittel, K. Mahata, Inorg. Chem. 2009, 48, 822–
824; q) A. K. Bar, R. Chakrabarty, K.-W. Chi, S. R. Batten,
P. S. Mukherjee, Dalton Trans. 2009, 3222–3229; r) B. H. Nor-
throp, Y.-R. Zheng, K.-W. Chi, P. J. Stang, Acc. Chem. Res.
2009, 42, 1554–1563.
a) F. Würthner, C.-C. You, C. Saha-Möller, Chem. Soc. Rev.
2004, 33, 133–146; b) E. R. Kay, D. A. Leigh, F. Zerbetto, An-
gew. Chem. Int. Ed. 2007, 46, 72–191; c) B. H. Northrop, H.-
B. Yang, P. Stang, Chem. Commun. 2008, 5896–5908; d) K.
Suzuki, S. Sato, M. Fujita, Nat. Chem. 2010, 2, 25–29.
a) S. J. Lee, A. Hu, W. Lin, J. Am. Chem. Soc. 2002, 124,
12948–12949; A. J. Sandee, J. N. H. Reek, Dalton Trans. 2006,
3385–3391; b) A. W. Kleij, J. N. H. Reek, Chem. Eur. J. 2006,
12, 4218–4227; c) S. J. Lee, S.-H. Cho, K. L. Mulfort, D. M.
Tiede, J. T. Hupp, S. T. Nguyen, J. Am. Chem. Soc. 2008, 130,
16828–16829; d) M. D. Pluth, R. G. Bergman, K. N. Raymond,
Acc. Chem. Res. 2009, 42, 1650–1659; e) M. Yoshizawa, J. K.
Klosterman, M. Fujita, Angew. Chem. Int. Ed. 2009, 48, 3418–
3438.
a) E. Holló-Sitkei, G. Szalontai, I. Lois, Á. Gömöry, F. Pollre-
isz, L. Pákányi, H. Jude, G. Besenyei, Chem. Eur. J. 2009, 15,
10620–10633; b) S.-S. Sun, A. J. Lees, Inorg. Chem. 2001, 40,
3154–3160.
a) P. De Wolf, S. l. Heath, J. A. Thomas, Inorg. Chim. Acta
2003, 355, 280–285; b) P. de Wolf, P. Waywell, M. Hanson, S. L.
[2]
a) M. Ruben, J. Rojo, F. J. Romero-Salguero, L. H. Uppadine,
J.-M. Lehn, Angew. Chem. Int. Ed. 2004, 43, 3644–3662; b)
L. K. Thompsona, O. Waldmann, Z. Xu, Coord. Chem. Rev.
2005, 249, 2677–2690; c) M. Ruben, U. Ziener, J.-M. Lehn, V.
Ksenofontov, P. Gütlich, G. B. M. Vaughan, Chem. Eur. J.
2005, 11, 94–100; d) N. Giuseppone, J.-L. Schmitt, J.-M. Lehn,
J. Am. Chem. Soc. 2006, 126, 16748–16763; e) X.-Y. Cao, J.
Harrowfield, J. Nitschke, J. Ramírez, A.-M. Stadler, N. Kyrit-
sakas-Gruber, A. Madalan, K. Rissanen, L. Russo, G.
Vaughan, J.-M. Lehn, Eur. J. Inorg. Chem. 2007, 2944–2965; f)
L. N. Dawe, L. K. Thompson, Dalton Trans. 2008, 3610–3618;
g) L. N. Dawe, K. V. Shuvaev, L. K. Thompson, Inorg. Chem.
2009, 48, 3323–3341; h) A.-M. Stadler, Eur. J. Inorg. Chem.
2009, 4751–4770; i) A. R. Stefankiewicz, J.-M. Lehn, Chem.
Eur. J. 2009, 15, 2500–2503; j) N.-F. She, M. Gao, X.-G. Meng,
G.-F. Yang, J. A. A. W. Elemans, A.-X. Wu, L. Isaacs, J. Am.
Chem. Soc. 2009, 131, 11695–11697.
a) R. Kramer, J.-M. Lehn, A. M. Rigault, Proc. Natl. Acad.
Sci. USA 1993, 90, 5394–5398; b) D. L. Caulder, K. N. Ray-
mond, Angew. Chem. Int. Ed. Engl. 1997, 36, 1439–1442; c) M.
Albrecht, Chem. Soc. Rev. 1998, 27, 281–287; d) R. Stiller, J.-
M. Lehn, Eur. J. Inorg. Chem. 1998, 7, 977–982; e) M. Al-
brecht, M. Schneider, H. Röttele, Angew. Chem. Int. Ed. 1999,
38, 557–559; f) M. Albrecht, Chem. Rev. 2001, 101, 3457–3498;
g) M. J. Hannon, L. J. Childs, Supramol. Chem. 2004, 16, 7–22;
h) M. Albrecht, Top. Curr. Chem. 2004, 248, 105–139; i) G.
Seeber, B. E. F. Tiedemann, K. N. Raymond, Top. Curr. Chem.
2006, 265, 147–183; j) J. R. Nitschke, Acc. Chem. Res. 2007,
40, 103–112.
a) P. J. Stang, B. Olenyuk, Acc. Chem. Res. 1997, 30, 502–518;
b) Yamamoto, A. M. Arif, P. J. Stang, J. Am. Chem. Soc. 2003,
125, 12309–12317; c) S.-S. Sun, C. L. Stern, S. T. Nguyen, J. T.
Hupp, J. Am. Chem. Soc. 2004, 126, 6314–6326; d) H.-B. Yang,
N. Das, F. Huang, A. M. Hawkridge, D. C. Muddiman, P. J.
Stang, J. Am. Chem. Soc. 2006, 128, 10014–10015; e) H.-B.
Yang, A. M. Hawkridge, S. D. Huang, N. Das, S. D. Bunge,
D. C. Muddiman, P. J. Stang, J. Am. Chem. Soc. 2007, 129,
2120–2129; f) H.-B. Yang, K. Ghosh, B. H. Northrop, Y.-R.
Zheng, M. M. Lyndon, D. C. Muddiman, P. J. Stang, J. Am.
Chem. Soc. 2007, 129,14187–14189; g) M. Ferrer, A. Gutirrez,
M. Mounir, O. Rossell, E. Ruiz, A. Rang, M. Engeser, Inorg.
Chem. 2007, 46, 3395–3406; h) L. Zhao, B. H. Northrop, P. J.
Stang, J. Am. Chem. Soc. 2008, 130, 11886–11888; i) H.-B.
Yang, K. Ghosh, Y. Zhao, B. H. Northrop, M. M. Lyndon,
D. C. Muddiman, H. S. White, P. J. Stang, J. Am. Chem. Soc.
2008, 130, 839–841; .-B. Yang, K. Ghosh, Y. Zhao, B. H. Nor-
throp, M. M. Lyndon, D. C. Muddiman, H. S. White, P. J.
Stang, J. Am. Chem. Soc. 2008, 130, 11886–11888; j) K. Ghosh,
H.-B. Yang, B. H. Northrop, M. M. Lyndon, Y.-R. Zheng,
D. C. Muddiman, P. J. Stang, J. Am. Chem. Soc. 2008, 130,
5320–5334; k) Y.-R. Zheng, P. J. Stang, J. Am. Chem. Soc. 2009,
131, 3487–3489; l) K. Ghosh, J. Hu, H.-B. Yang, B. H. Nor-
throp, H. S. White, P. J. Stang, J. Org. Chem. 2009, 74, 4828–
4833; m) S.-S. Li, B. H. Northrop, Q.-H. Yuan, L.-J. Wan, P. J.
Stang, Acc. Chem. Res. 2009, 42, 249–259.
[6]
[7]
[3]
[4]
[8]
[9]
[5]
a) M. Fujita, N. Fujita, K. Ogura, K. Yamaguchi, Nature 1999,
400, 52–55; b) B. Olenyuk, J. A. Whiteford, A. Fechtenkötter,
P. J. Stang, Nature 1999, 398, 796–799; c) U. Radhakrishnan,
M. Schweiger, P. J. Stang, Org. Lett. 2001, 3, 3141–3143; d) M.
Fujita, K. Umemoto, M. Yoshizawa, N. Fujita, T. Kusukawa,
K. Biradha, Chem. Commun. 2001, 509–518; e) S. R. Seidel,
P. J. Stang, Acc. Chem. Res. 2002, 35, 972–983; f) M. Fujita,
M. Tominaga, A. Hori, B. Therrien, Acc. Chem. Res. 2005, 38,
371–380; g) H. B. Yang, K. Ghosh, N. Das, P. J. Stang, Org.
[10]
[11]
476
www.eurjoc.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2011, 469–477

Self-Assembly of Palladium Metallo-Macrocycles
Heath, A. J. H. M. Meijer, S. J. Teat, J. A. Thomas, Chem. Eur.
J. 2006, 12, 2188–2195.
[12] P. de Wolf, S. l. Heath, J. A. Thomas, Chem. Commun. 2002,
2540–2541.
[18] a) Z. Qin, M. C. Jennings, R. J. Puddephatt, Inorg. Chem. 2003,
42, 1956–1965; b) A. Kaiser, P. Bäuerle, Top. Curr. Chem. 2005,
249, 127–201; c) T. Weilandt, R. W. Troff, H. Saxell, K. Ris-
sanen, C. A. Schalley, Inorg. Chem. 2008, 47, 7588–7598.
[19] P. J. Stang, D. H. Cao, J. Am. Chem. Soc. 1994, 116, 4981–
4982.
[13] S. Müller, B. Liepold, G. J. Roth, H. J. Bestmann, Synlett 1996,
521–522.
[14] a) M. C. Haberecht, J. M. Schnorr, E. V. Andreitchenko, C. G.
Clark, M. Wagner, K. Müllen, Angew. Chem. Int. Ed. 2008, 47,
1662–1667; b) R. Ziessel, F. Suffert, M.-T. Youinou, J. Org.
Chem. 1996, 61, 6535–6546.
[15] Cache Program Package, Fujitsu Ltd., Krakow, Poland.
[16] a) M.-F. Ng, S. Yokojima, D. Zhou, G. Chen, Chem. Phys.
Lett. 2000, 327, 374–380; b) A. H. Göller, U.-W. Grummt,
Chem. Phys. Lett. 2002, 345, 233–242.
[20] X. Yu, H. Lin, Z. Cai, H. Lin, Tetrahedron Lett. 2007, 48,
8615–8618.
[21] G. W. Kabalka, L. Wang, Tetrahedron Lett. 2002, 43, 3067–
3068.
[22] This bipyridine derivative has been synthesized in literature by
a relatively complicated five step procedure[14a] or through a
two step procedure[14b] with an intermediate, which is hard to
purify.
[17] M. A. Balbo, C. Kaiser, A. Khan, S. Hecht, Top. Curr. Chem.
2005, 245, 89–150.
Received: October 4, 2010
Published Online: December 1, 2010
Eur. J. Org. Chem. 2011, 469–477
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
477