Synthesis of [5]rotaxanes containing Bi- and tridentate coordination sites in the axis

Article abstract of DOI:10.1002/chem.201002220

A new example of a linear [5]rotaxane has been synthesized by using the traditional "gathering-and-threading" approach but based on an unusual axle incorporating a symmetrical bis(bidentate) chelating fragment built on a 4,7-phenanthroline core. The stopp

Full text of DOI:10.1002/chem.201002220

FULL PAPER
DOI: 10.1002/chem.201002220
Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites
in the Axis
[
a]
[a]
[a]
[a]
Jean-Paul Collin,* Stꢀphanie Durot,* Michel Keller, Jean-Pierre Sauvage,*
[
a]
[b]
[b]
Yann Trolez, Mario Cetina, and Kari Rissanen
Abstract: A new example of a linear
5]rotaxane has been synthesized by
dinating groups present in the frag-
ments to be interconnected (terpy and
bidentate chelating groups), thus inhib-
iting potential detrimental side reac-
tions during the copper-catalyzed stop-
pering reaction. Since the external
fragments and the central core of the
system contain tri- and bidentate che-
lating units, respectively, the axle of the
final [5]rotaxane incorporates two
types of coordinating units: two exter-
nal terpy groups (terpy: 2,2’:6’,2’’-ter-
pyridine) and two central bidentate li-
gands. Such a situation enables the
system to tidy two different metals cen-
ters, and to localize them in a priori
well-defined positions. This is what was
observed when mixing the free ligand
[
using the traditional “gathering-and-
threading” approach but based on an
unusual axle incorporating a symmetri-
cal bis(bidentate) chelating fragment
built on a 4,7-phenanthroline core. The
stoppering reaction is particularly note-
worthy since, instead of using a trivial
bulky stopper as precursor to the
blocking group, two semistoppered
copper-complexed [2]pseudorotaxanes
2
+
+
with a mixture of Zn and Li : the
zinc(II) ions were unambiguously
shown to occupy the external sites,
+
whereas the Li cations were found in
the central part of the [5]rotaxane. An
X-ray diffraction study carried out on a
[3]pseudorotaxane, the axis of which is
similar to the central part of the [5]ro-
2
+
taxane axle, demonstrates that Zn is
clearly five-coordinate, the fifth ligand
being a counterion, even when the co-
ordination site of the pseudorotaxane
is designed for four-coordinate metals,
which is in marked contrast with cop-
(
namely [2]semirotaxanes) are used,
which leads to the desired [5]rotaxane
in good yield. The efficiency of the
method relies on the use of “click”
chemistry, with its very mild conditions,
and on the protection by a transition-
metal (copper(I)) of the various coor-
Keywords: click chemistry · copper ·
lithium · rotaxanes · zinc
+
per(I) or Li .
Introduction
ties of which are indisputably nontrivial, from the beginning
[1]
of topological chemistry. The synthesis of such compounds
has experienced an explosive development since the intro-
duction of template strategies either based on transition
Although rotaxanes are not strictly speaking topologically
interesting molecules (their molecular graph is planar), they
have been associated with catenanes, the topological proper-
[2–17]
metals or by using organic building blocks.
An efficient
alternative approach was proposed long ago by Harrison. It
is based on the statistical threading process at high tempera-
ture of a stringlike fragment through a ring used as the sol-
vent, the string being end-functionalized by two bulky
groups. These groups were able to act as stoppers under
mild conditions but, at the same time, they could be thread-
ed through the ring cavity at high temperature. After high
[
a] Dr. J.-P. Collin, Dr. S. Durot, M. Keller, Prof. J.-P. Sauvage,
Dr. Y. Trolez
Laboratoire de Chimie Organo-Minꢀrale, Institut de Chimie
LC3 UMR 7177 du CNRS, Universitꢀ de Strasbourg
4
rue Blaise Pascal, 67070 Strasbourg Cedex (France)
Fax : (+33)368851368
E-mail: jpcollin@chimie.u-strasbg.fr
sdurot@chimie.u-strasbg.fr
sauvage@chimie.u-strasbg.fr
temperature threading, cooling down, and then freezing, the
[18]
[
2]rotaxane structure was obtained.
A related strategy,
[
b] M. Cetina, Prof. K. Rissanen
based on crown ethers, used as rings, and poly(ethylene gly-
cols), playing the role of threads, was also developed by
Department of Chemistry, Nanoscience Center
University of Jyvꢁskylꢁ, P.O.Box 35
[19]
Zilkha and co-workers in 1976. The first templated strat-
egy leading to [2]rotaxanes in good yields and following a
simple experimental protocol was reported by Ogino in
4
0014 Jyvꢁskylꢁ (Finland)
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem201002220.
Chem. Eur. J. 2011, 17, 947 – 957
ꢂ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
947

[
13]
1
981. It consists in threading a polymethylene fragment of
the a,w-diaminoalcane type through a cyclodextrin and, sub-
sequently, stoppering the systems by attaching cobalt(III)
nated to any protective ligand, the results were also disap-
pointing. It thus appeared necessary to use an ancillary
ligand, able to partially complex the catalytic copper(I)
center and protect it towards potentially coordinating frag-
ments of the compounds to be “clicked”. Two remarkable
examples of such protected catalysts have recently been de-
AHCTUNGTRENNUNG
complexes at both ends of the thread. Since this early work,
more than 1000 reports on rotaxanes have been published in
the literature. Poly- and multirotaxanes constitute a sub-
class of such compounds. These systems are important in re-
[20]
[72–74]
scribed,
which seem to solve the interference problem
[14,21–36]
lation to polymer chemistry
sophisticated molecular machines, such as molecular mus-
or for the elaboration of
between catalytic copper and functional groups belonging to
the substrates, making the catalyst substantially more stable
than without added ligand. We selected a modified tren, de-
[
22,37–47]
[48]
[6,35,49–53]
cles,
elevators, or receptors.
We would now
like to report the copper(I)-templated synthesis of [5]ro-
taxanes consisting of four identical rings threaded by a long
stringlike fragment. This thread contains two bidentate che-
lates and two tridentate coordinating units. The synthesis of
metal-free [5]rotaxane will be described. We will also discuss
some of the coordination properties of the free molecule
and, in particular, its ability to sort and arrange metal ions
noted tren’ ([Cu ACHTUNGTERNNUN(G tren’)]Br; tren: tris(2-aminoethyl)amine),
+
2+
with different coordination numbers, such as Li and Zn
.
I
Results and Discussion
as the stabilizing ligand for Cu , similar to Vincent and co-
[73]
workers. The efficiency of the catalyst turned out to be
dramatically improved, as discussed in the following sections
of the present report.
The incorporation of bidentate chelates of the 2,2’-bipyri-
dine (bipy) family and tridentate ligands, such as 2,2’:6’,2’’-
terpyridine (terpy), in the same axis is related to the dynam-
Strategy and design of the system: Among the various tem-
plate strategies proposed for making rotaxanes, the use of
transition metals able to induce the threading process of a
stringlike molecular fragment through a ring turned out to
be particularly efficient. This “gathering and threading” ap-
proach has been used extensively in our group for making
ic properties of rotaxanes behaving as molecular “shut-
[54]
[75–92]
catenanes and rotaxanes. The second step is the attach-
ment of bulky groups at both ends of the thread, so as to
tles”.
These rotaxanes with differentiated coordination
sites could also be of interest in terms of selective complexa-
tion of given ions, offering the possibility of incorporating
within the same compound metal centers with different co-
ordination numbers, these metals being located in precisely
defined coordination sites. The general synthesis principle is
depicted in Scheme 1.
The synthesis of copper(I)-complexed [2]rotaxanes and
[3]rotaxanes by means of click chemistry has already been
successfully achieved according to strategy a (Scheme 1a), in
“
“
freeze” the threaded structure of the compound. This
stoppering” reaction has been performed by using a large
[
13,15,17,55–61]
variety of reactions.
Presently, the rotaxane com-
the 1,3-dipolar cycloaddition of
[62–64]
munity seems to favor
an azide to a terminal alkyne affording a triazole (i.e., Huis-
for the uncatalyzed reaction and “click”
chemistry for the copper-catalyzed azide–alkyne cycloaddi-
(CuAAC)). Our group has also used click reactions
for making various rotaxanes, often with very high yields,
which is the reason why we also favored this
[
65]
gen reaction
[
66,67]
tion
[68]
which the axis bears either a bipy or a 2,9-diphenyl-1,10-
phenanthroline (dpp) fragment or strategy b (Scheme 1b),
in which the axle is a bis[3,8-(o-pyridyl)-4,7-phenanthroline]
[69]
[
52,53,68–71]
method.
The only potential difficulty inherent to
ACHTUNGTRENNUNG
[71]
the click conditions is the presence of copper. Copper(I) will
be at the same time the catalyst and the template element
so that it will be important to avoid any kind of interference
between the catalytic and templating functions of the metal,
in spite of the presence of various coordinating groups in
the molecules undergoing the click reaction. We recently at-
tempted to prepare multirotaxanes incorporating both
metal-complexed ligands and free ligands by means of click
chemistry. Unfortunately, the results were very disappoint-
ing and there were clear indications that the presence of
free ligands was detrimental to the formation of the desired
stoppered complexes. Another series of experiments turned
out to be negative but informative. When “normal” click
chemistry was tried with free ligand or copper(I)-complexed
coordinating fragments, “normal” meaning that the cop-
per(I) centers supposed to act as catalysts were not coordi-
bis(bidentate) unit. The isolated yields for the preparation
of these metallorotaxanes were good and click chemistry
seemed to be well adapted to the copper(I)-template synthe-
sis of interlocked molecules. The extension of CuAAC click
chemistry to terpy-containing axle [2]semirotaxane and
[5]rotaxane synthesis is reported here.
Synthesis of [2]semirotaxanes: A threadlike fragment 3,
consisting of a terpy, bearing azide functions at each end
(Scheme 2), was prepared in two steps from the previously
[93]
reported 5,5”-dimethyl-2,2’:6’,2’’-terpyridine (1). By using
controlled conditions regarding the number of NBS equiva-
lents, light, heat, and duration, the 5,5’’-di(bromomethyl)-
2,2’:6’,2’’-terpyridine (2) could be isolated with an acceptable
[38]
yield (48%). Easy and quantitative conversion to the dia-
zido derivative 3 was performed by addition of a slight
948
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Chem. Eur. J. 2011, 17, 947 – 957

Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites
FULL PAPER
6
1%. This is a good yield, con-
sidering that only one azide
function of the symmetric ter-
pyridine 3 has been converted.
It was achieved thanks to the
use of an excess of [Cu-
AHCTUNGTRENNUN(G CH CN) ] ACHUTNGTREUNNGN[ PF ] on one hand,
3 4 6
and of only 0.5 equivalent of
acetylenic compound 4 on the
other hand. Furthermore, non-
reacted 3 could be recycled.
The “gathering and thread-
ing” reaction between the cop-
per(I) (zinc(II), respectively)
complex of the 30-membered
ring 5 and the terpy string 3 led
quantitatively to the expected
+
2+
Scheme 1. Construction principle of multirotaxanes by copper(I)-driven “gathering and threading” followed by [2]semirotaxane
7
(8 , re-
stoppering; the coordinating fragments are represented by U-shaped (bidentate chelates) or M-shaped (triden-
spectively), as confirmed by
proton NMR spectroscopic
studies.
tate chelates) symbols; the small sphere is a copper(I) atom and the big one represents the stopper: a) syn-
thesis of a [2]rotaxane, b) synthesis of a [3]rotaxane, c) synthesis of a [4]rotaxane, d) synthesis of a [5]rotaxane.
1
The H NMR spectra were in
accordance with the postulated
+
2+
structures of 7 and 8 . In par-
1
ticular, the H NMR spectrum
of 7 was significantly different
+
from the spectra of both the
copper(I)-complexed-macrocy-
cle and the dissymmetric terpyr-
idine 6. This confirmed that
+
2+
compounds 7 (and 8 ) were
metalated semirotaxanes. The
phenyl protons (identified as d
and e, see Figure 1) of the mac-
rocycle component 5 undergo a
strong upfield shift by cop-
per(I)-induced threading of 6,
+
to afford 7 . The copper(I)–
+
[
2]semirotaxane 7 was subse-
quently used as a stopper for
the synthesis of a new linear
[
5]rotaxane.
Synthesis of [5]rotaxane: To
the best of our knowledge, very
few examples of linear [5]ro-
taxanes were reported in the lit-
[94–98]
erature.
The synthesis was
carried out by following the
classical CuAAC strategy but
an important difference with
previous cases should be
stressed: in the present case,
Scheme 2. Precursors and synthesis of terpy-containing [2]semirotaxanes by CuAAC click chemistry. NBS=N-
bromosuccinimide.
excess of sodium azide in a mixture of DMSO and water
(
2:1) at 408C.
the stopper precursor is a semirotaxane (copper(I)–[2]semi-
rotaxane 7 ) and not a trivial bulky compound. This semiro-
+
A dissymmetric terpyridine 6 with one azide function and
one bulky group was synthesized from compounds 3 and 4
by using a statistical “click chemistry” reaction in a yield of
taxane used as a stopper precursor is, itself, half-stoppered,
making the final product a complete rotaxane.
Chem. Eur. J. 2011, 17, 947 – 957
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949

J.-P. Collin, S. Durot, J.-P. Sauvage et al.
CuAAC reactions are per-
formed simultaneously by using
a highly functionalized stopper
precursor. Given that the deme-
talation process of such a rotax-
ane is generally quantitative,
this overall yield can be consid-
ered as the yield of the stopper-
ing reaction.
[
5]rotaxane 11 was character-
ized by mass spectrometry
ESMS) and 1D and 2D
(
1
H NMR spectroscopy (COSY,
ROESY) experiments. Particu-
larly noteworthy is the chemical
nonequivalence of two types of
macrocycles in this system: the
internal and the external ones.
The positions of these macrocy-
cles were unambiguously deter-
mined by interfragment NOE
1
+
Figure 1. H NMR spectra of a) macrocycle 5 (300 MHz), b) copper(I) [2]semirotaxane 7 (300 MHz), and interactions, for example, pro-
c) dissymmetric terpyridine 6 (500 MHz) in CD Cl
2
2
.
tons H-d’ (which belong to the
external macrocycles, see
Scheme 3) correlate to protons
of the external part of the axle (H-16, H-21, and H-23),
whereas protons H-d (which belong to the internal macrocy-
cles) correlate to protons of the internal part of the axle (H-
3, H-7, H-5, and H-10).
Even though all macrocycles are free to rotate around
and to translate along the axle, the two internal macrocycles
are more shielded than the external macrorings. Indeed,
each one is located between two other macrocycles and is
thus more exposed to the ring current effect of the various
The central complex was the symmetrical [3]pseudoro-
taxane synthesized quantitatively from the bis(bidentate)
chelate 9, two macrocycles 5, and two copper(I) ions accord-
[71]
ing to a previously published procedure.
Combining these two parts, 7 and 10 , allowed for the
synthesis of [5]rotaxane 11 by a double click chemistry reac-
.
+
2+
tion with catalyst [Cu ACHUTNGRNENGU( tren’)]Br and subsequent demetala-
tion by KCN (Scheme 3). [5]Rotaxane 11 was obtained in a
yield of 75%, which is excellent considering that two
Scheme 3. Synthesis of the [5]rotaxane 11.
950
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Chem. Eur. J. 2011, 17, 947 – 957

Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites
FULL PAPER
aromatic fragments belonging to the two surrounding rings.
The internal rings thus undergo a more important ring-cur-
rent effect than their external counterparts, the external
macrocycles being located between one macrocycle and a
stopper. This effect is particularly well illustrated by consid-
ering H-e and H-e’: d=6.42 ppm for the internal macrocy-
clic component and d=6.64 ppm for the external rings.
four ions are coordinated in precisely defined and symmetri-
cal positions. A Li NMR spectroscopic analysis showed just
7
one peak at d=5.33 ppm, confirming that there was just one
+
type of Li in the system, either at the internal or the exter-
nal position. From previous work, it has been established
2
+
that Zn “prefers” to be pentacoordinated and thus located
in the external site (consisting of a tridentate ligand, part of
the axle, and a bidentate chelating group, incorporated in
[
29]
+
Coordination chemistry studies: The coordination properties
of [5]rotaxane 11 were investigated. Actually, the ability of
the ring). By contrast, Li generally “prefers” to be tetra-
1
coordinated. H NMR spectroscopic observations undoubt-
2
+
+
+
this rotaxane to complex two metal ions, Zn and Li , was
edly indicated the positions of the two Li ions and of the
2
+
2+
studied. We first remetalated compound 11 with Zn . Four
equivalents of Zn(OTf) in
two Zn
ions (Figure 2). The most striking clue is the
AHCTUNGTRENNUNG
2
methanol were added to a solu-
tion of 11 in dichloromethane.
After workup, the desired
8
+
metalated compound 12 was
obtained in a yield of 92%.
This compound was character-
1
ized by H NMR spectroscopy
(
1D, COSY, NOESY) as well as
by mass spectrometry (ESMS).
It is noteworthy that CDCl as
3
an NMR solvent precluded the
possibility to obtain well-re-
solved peaks. The lithiated
counterpart of this rotaxane
was more difficult to obtain.
Indeed, eight equivalents of
1
8+
4+
6+
Figure 2. Aromatic part of the H NMR spectra (300 MHz) of [5]rotaxanes 11, 12 , 13 , and 14 ; the aster-
isk indicates residual CHCl for 11.
LiBF in methanol (with a few
4
3
drops of NEt to eliminate re-
3
sidual HBF ) were necessary to
4
obtain the desired four-lithiated
rotaxane 13 . No workup was possible because of the insta-
bility of the resulting complex, except for evaporation of sol-
4
+
2+
chemical shift of proton H-6, d
A
H
N
T
E
N
G
-
8
+
4
+
vents. However, this rotaxane 13 could be characterized
A
H
U
G
R
N
U
G
ACHTUNGTRENNUNG
1
7
+
4+
by H and Li NMR spectroscopy. As expected, two signals
7
2+
+
6+
of equal intensity were detected by Li NMR spectroscopy
and in the mixed Zn /Li [5]rotaxane 14 , it is much less
shielded at d(H-6)=7.16 and 7.20 ppm, respectively. This
observation indicates that in 14 the Zn ions are not co-
ordinated to bidentate units of the axle, but to the terpy
fragments of the axle, satisfying a pentacoordinated geome-
at d=5.33 and 4.63 ppm, which indicated that two types of
ACHTUNGTRENNUNG
+
6+
2+
magnetically nonequivalent Li were present in the system:
+
internal and external Li . Moreover, our attempts to com-
4
+
pletely characterize compound 13 by mass spectrometry
remained unsuccessful. We detected partly or totally decom-
plexed species, with no, one, or two Li ions incorporated in
+
try. The Li ions are, therefore, situated in the internal posi-
+
tions.
the system. Nevertheless, the NMR spectroscopic observa-
tions did not leave any doubt about the structure of com-
To understand the amazing chemical shift of proton H-6
8
+
in rotaxane 12 , a new pseudorotaxane incorporating the
4
+
2+
pound 13 . Once the ability of rotaxane 11 to complex
central part of the axle, Zn and the same macrocycles as
2
+
+
Zn and Li was demonstrated, we wondered whether this
rotaxane could be able to complex two equivalents of each
ion, leading to a single species with the ions located in well
defined coordination sites. Each ion could be either at an in-
ternal (four-coordinate) or an external (five-coordinate) po-
those of 11 was prepared. The central part of the axle was
synthesized from 3,8-bis(4-bromo-2’-pyridyl)-4,7-phenan-
throline (15), the synthesis of which has already been pub-
[99]
lished. Compound 15 was submitted to a double Sonoga-
shira coupling with trimethylsilylacetylene, [PdCl (PPh ) ],
ACHTUNGTRENNUNG
2
3 2
sition. Adding simultaneously two equivalents of Zn
A
H
U
G
R
N
N
(OTf)
and CuI in a mixture of DMF and NEt to give compound
2
3
and two equivalents of LiBF led to a well-resolved
16 (Scheme 5, yield: 31%). Compound 16 was then involved
in a threading reaction with two equivalents of macrocycle 5
4
1
H NMR spectrum with the same number of signals as ro-
8
+
4+
6+
taxanes 12 and 13 . The resulting product, 14 , thus has
and two equivalents of Zn ACHTUNGTRENNUNG( OTf) to afford the expected
2
8
+
4+
4+
the same symmetry as 12 and 13 and, therefore, the
[3]pseudorotaxane 17 in a quantitative yield. This [3]pseu-
Chem. Eur. J. 2011, 17, 947 – 957
ꢂ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
951

J.-P. Collin, S. Durot, J.-P. Sauvage et al.
8
+
4+
6+
Scheme 4. Syntheses of [5]rotaxanes 12 , 13 , and 14 by remetalation of compound 11. The figure is dealing with three independent experiments:
2
+
8+
+
4+
a) consists in adding four equivalents of Zn with formation of 12 , b) a large excess of Li was added to the free ligand 11; 13 was obtained, and
2
+
+
6+
c) two equivalents of a one-to-one mixture of Zn and Li was reacted with 11 to afford 14 quantitatively.
4
+
Scheme 5. Synthesis of [3]pseudorotaxane 17
.
4
+
1
dorotaxane 17 was characterized by H NMR spectrosco-
ular chemical shift of proton H-6 at d AHCTUNGTERNNUN(G H-6)=6.50 ppm. Con-
py (1D, COSY, NOESY) and mass spectrometry (ESMS).
The H NMR spectrum of this species confirmed the partic-
sequently, this observation is due to an intrinsic property of
the coordination of Zn to bidentate units of the axle. It
1
2+
952
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Chem. Eur. J. 2011, 17, 947 – 957

Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites
FULL PAPER
confirms the conclusions of the previously discussed
Table 1. Bond lengths [ꢃ] and angles [8] around the zinc ions.
1
H NMR spectroscopic study.
X-ray quality crystals of [17]
Zn1ꢀN9
2.041(7)
2.174(7)
2.041(8)
2.334(6)
N9-Zn1-N18
N9-Zn1-N49
N9-Zn1-O1A
N40-Zn1-N18
N49-Zn1-N18
N18-Zn1-O1A
N40-Zn1-N49
N40-Zn1-O1A
N49-Zn1-O1A
N28-Zn2-N82
N28-Zn2-N91
80.3(3)
146.4(3)
84.2(2)
115.0(3)
100.6(3)
160.1(2)
82.9(4)
84.4(3)
85.6(3)
127.7(3)
ꢀ
ꢀ
Zn1 N18
Zn1ꢀN49
Zn1ꢀO1A
A
H
U
G
E
N
N
[TfO ] were grown by slow
4
diffusion of diisopropylether into an acetone solution. The
X-ray structure (Figure 3) confirms the [3]pseudorotaxane
Zn2ꢀN28
Zn2ꢀN26
2.028(8)
2.140(7)
1
46.2(3)
Zn2ꢀN82
Zn2ꢀN91
Zn2ꢀO1B
2.029(9)
2.073(9)
2.263(6)
N28-Zn2-O1B
N26-Zn2-N28
N26-Zn2-N82
N26-Zn2-N91
N26-Zn2-O1B
N82-Zn2-N91
N82-Zn2-O1B
N91-Zn2-O1B
N26-Zn2-N91
83.0(3)
79.2(3)
118.4(3)
98.4(3)
153.1(3)
83.4(4)
88.5(3)
85.3(3)
98.4(3)
I
II
The change of the metal ions from tetrahedral Cu to Zn
ions leads to a dramatic modification of the overall structure
II
of the [3]rotaxane. Zn usually has a significantly different
I
chemistry than Cu in terms of geometry and coordination
number. This is well illustrated in the present study, since in
4
+
1
7
both Zn ions exhibit a similar penta-coordination
(
Table 1.), the fifth coordination sites are occupied with the
ꢀ
triflate anions, resulting in a [Zn (17)
A
H
U
G
R
N
N
(OTf) ]
A
H
N
T
N
U
G
2
2
2
ture. The two remaining triflate anions and the solvent mol-
ecules (1.5 acetone and one water) are located/trapped into
a V-shaped cleft induced by the penta-coordinated Zn ion
and subsequent reorientation of the phenanthroline-contain-
ing macrocycles with respect to the axle. In the correspond-
I
[71]
ing Cu -[3]rotaxane, the wheels are perpendicular due to
I
4+
the tetrahedral coordination of the Cu ions, whereas in 17
the wheels are titled towards each other, so that the phen
moieties are nearly touching each other, creating a triangle
between the axle and the two wheels (the angle between the
phen moieties is 598 and the angle between the axle and the
phen moieties 658, resulting is a nearly perfect triangle,
Figure 3). As a consequence the poly(ethyleneglycol) parts
of the wheel are widely separated (the distances between
the carbon atoms at the open-end of the V is >10 ꢃ). Thus
Figure 3. The ball and stick (top) and the CPK (bottom) representations
of [3]pseudorotaxanes: a) 17 and b) its Cu counterpart. The non-co-
ordinated triflate anions and solvent molecules are omitted for clarity.
4
+
I
[71]
4
+
the overall structure of 17 can be described by a slightly
modified letter A, namely,
Due to the different coordination geometry around the
.
structure of the compound. Due to the nature of the axle,
4
+
the Zn atoms reside on the same side of the axle (cis-rotax-
metal ion the phen wheels in 17 are not eclipsed as they
II
I
[71]
ane). The Zn ions show a distorted penta-coordination
are in the corresponding Cu analogue. The torsion angle
between the centroids of the phen wheels and the axle, de-
fined as phencen-Zn1-Zn2-phencent is 21.238. Also the metal
ion to metal ion distance is slightly different between the Zn
and Cu rotaxanes. The penta-coordination of the Zn ions re-
sults in a Zn···Zn distance of 8.2 ꢃ, whereas the Cu···Cu dis-
tance in the Cu analogue is 7.8 ꢃ.
with N-Zn-N and N-Zn-O bond angles between 80–1608 and
the bond lengths 2.03–2.17 ꢃ for ZnꢀN and 2.26–2.33 ꢃ for
the ZnꢀO bonds, respectively (Table 1). As in the corre-
I
[71]
sponding Cu -[3]rotaxane,
the long (Si···Si distance of
2.4 nm) axle is not linear, but is bent by the coordination to
the Zn ions so that the angle between the centroid of the
axle and the terminal Si atoms is 165.48, slightly more linear
than in the Cu rotaxane (1648).
The overall geometry of the [3]pseudorotaxane is to a
large extent dictated by the asymmetry of each bidentate
I
Chem. Eur. J. 2011, 17, 947 – 957
ꢂ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
953

J.-P. Collin, S. Durot, J.-P. Sauvage et al.
chelate belonging to the axle. The presence of a central
HC=CH group (H-6 positions of the central 4,7-phenanthro-
line nucleus) has a marked steric effect on each bidentate
chelating unit. The two positions a to the nitrogen atoms
are markedly different since one of them (the external one)
is not substituted (position numbered 5 in Scheme 3),
whereas the other bears a CH=CH substituent. Formation
of five-coordinate complexes will thus imply that the fifth
ligand (either solvent or counterion) be coordinated to the
complexed metal on the most accessible site and thus close
to the external nitrogen atoms. This is exactly what the X-
ray structure shows, with coordination of two triflate ions on
the nonsubstituted side of each bipylike fragment, thus forc-
ing the two rings to be tilted, with the back portion of each
ring-incorporated 1,10-phenanthroline being close to that of
the other ring. As a consequence, proton H-6 is in the
shielding cone of each ring-incorporated 1,10-phenanthro-
line, which explains the strong upfield shift observed for H-6
coupling constants in Hz if applicable, the number of protons implied,
and finally the assignment.
Mass spectra were obtained by using a Bruker MicroTOF spectrometer
(
ESMS).
5
,5’’-Di(azidomethyl)-2,2’:6’,2’’-terpyridine (3): NaN (0.676 g, 10.4 mmol)
3
and water (21 mL) were added to a suspension of di(bromomethyl)ter-
pyridine (2) (1.44 g, 3.44 mmol) in DMSO (30 mL). The white suspension
was heated at 408C overnight (with aluminum foil around the flask to
protect the mixture from light). The aqueous layer was five times extract-
ed with CH Cl and the organic phase dried over MgSO and then con-
2 2 4
centrated under vacuum. DMSO was removed by trap to trap distillation
at 408C or by filtration over alumina. A white solid product was obtained
1
quantitatively (1.19 g). M.p. 1028C; H NMR (300 MHz, CDCl , 258C):
3
4
3
d=8.64 (d, J=2.4 Hz, 2H; H-6,6’’), 8.62 (d, J=7.9 Hz, 2H; H-3,3’’),
.46 (d, J=7.9 Hz, 2H; H-3’,5’), 7.96 (t, J=7.9 Hz, 1H; H-4’), 7.82 (dd,
J=7.9, J=2.4 Hz, 2H; H-4,4’’), 4.46 ppm (s, 4H; H-1); MS (ES): m/z
3
3
8
3
4
+
+
(
%): calcd for [C17
Dissymmetric terpyridine (6): Di(azidomethyl)terpyridine (3) (0.440 g,
.28 mmol) was dissolved in distilled and degassed CH Cl (7.5 mL)
under argon. [Cu(CH CN) ][PF ] (0.692 g, 1.86 mmol) dissolved in de-
gassed CH CN (5 mL) was added to the above mixture under argon. The
dark-red solution was agitated for 0.5 h. Then, stopper (412 mg,
.76 mmol) and Na CO (62 mg, 0.58 mmol) were added under argon.
The mixture was stirred for 16 h 30 min under argon. KCN (1.478 g,
2.7 mmol) diluted in the minimum amount of distilled water was then
added and the mixture was stirred for 2 h 30 min. Then, distilled water
20 mL) was added and this layer was extracted with CH Cl . The organic
layer was dried over Na SO , the solvent evaporated, and the resulting
yellow residue was purified by alumina chromatography (elution ether)
13 9
H N H] : 344.14; found: 344.11 (100) [M+1H] .
1
2
2
A
H
U
G
R
N
N
3
4
ACHTUNGTRENNUNG
6
3
4
+
4
in the [3]pseudorotaxane 17 , and by extension, in [5]ro-
0
2
3
8
+
taxane 12
.
2
(
2
2
Conclusion
2
4
A new linear [5]rotaxane prepared according to the tradi-
tional template effect of copper(I) shows novel coordination
properties due to the presence of two types of coordinating
fragments in its axis. In particular, the metal-free molecule
1
to give pure 6 (411 mg, 0.464 mmol, 61%). H NMR (500 MHz, CD
258C): d=8.67 (d, J=2.1 Hz, 1H; H-6’’), 8.65 (d, J=2.1 Hz, 1H; H-6),
8.64 (d, J=8.1 Hz, 1H; H-3’’), 8.62 (d, J=8.1 Hz, 1H; H-3), 8.48 (2dd,
J=7.8, J=0.9 Hz, 2H; H-3’, H-5’), 7.97 (t, J=7.8 Hz, 1H; H-4’), 7.82
dd, J=8.1, J=2.1 Hz, 1H; H-4), 7.79 (dd, J=8.1, J=2.1 Hz, 1H; H-
’’), 7.68 (s, 1H; H-7), 7.26 (d, J=8.8 Hz, 6H; H-12), 7.15 (d, J=9.0 Hz,
H; H-10), 7.14 (d, J=8.8 Hz, 6H; H-11), 6.86 (d, J=9.0 Hz, 2H; H-9),
2
Cl
2
,
4
3
3
3
3
4
3
3
4
3
4
(
4
2
2
+
when reacted with a 1:1 mixture of a divalent metal (Zn ),
3
3
+
eager to be five-coordinate, and a monovalent cation (Li ),
3
3
which can easily be four-coordinate, affords a single species
quantitatively with the four metal centers at the right
5.64 (s, 2H; H-2), 5.16 (s, 2H; H-8), 4.48 (s, 2H; H-1), 1.29 ppm (s, 27H;
+
H-13); MS (ES): m/z (%): calcd for [C57
886.48 (100) [M+1H] .
59 9 1
H N O H] : 886.49; found:
+
2
+
+
places: two Zn cations at the periphery and two Li ions
coordinated with the central core of the [5]rotaxane. An at-
tractive X-ray structure of a dizinc [3]pseudorotaxane con-
The compound decomposes as a solid above 1708C. The melting point of
6
could thus not be measured.
I
Cu –[2]semirotaxane ([7]
A
H
U
G
R
N
U
G
6
]):
A
solution of [Cu
CN (0.4 mL) was added to a
degassed solution of macrocycle 5 (9.6 mg, 17 mmol) in dry CH Cl
3 4 6
ACTHUNGTNERNUN(G CH CN) ] ACHTUNGTRENNUNG[ PF ]
2
+
firms that Zn prefers to be five-coordinate even if the or-
ganic ligands offered to it are expected to lead to a four-co-
ordinate complex. In this case, each zinc(II) cation is coordi-
(
6.3 mg, 17 mmol) in dry and degassed CH
3
2
2
(0.4 mL) and it was stirred at room temperature over 15 min under an
inert atmosphere. degassed solution of dissymmetric terpyridine
15.0 mg, 17 mmol) in dry CH Cl (2.1 mL) was then added to this orange
ꢀ
A
nated to an additional ligand (OTf ) which satisfies its coor-
(
2
2
dination requirements. The synthesis of related compounds
containing a smaller number of threaded rings than coordi-
nation sites in the axle should lead to molecular systems for
which it will be possible to trigger translation motions of
given rings from one position to another on the axle.
solution by cannula. The mixture turned immediately intensely dark red
I
and was left to react for 30 min. After evaporation of the solvents, Cu –
[2]semirotaxane (29.6 mg, 17.0 mmol) was obtained quantitatively.
1
3
H NMR (300 MHz, CD
2
Cl
2
, 258C): d=8.47 (d, J=8.1 Hz, 2H; H-b),
3
8
2
(
.09–8.02 (m, 3H; H-3’, H-4’, H-5’), 8.02 (s, 2H; H-a), 7.91 (d, J=8.1 Hz,
H; H-c), 7.92–7.87 (m, 2H; H-3,3’’), 7.79 (d, J=1.3 Hz, 2H; H-6’’), 7.75
4
4
3
s, 1H; H-7), 7.66 (d, J=1.3 Hz, 2H; H-6), 7.47 (d, J=8.6 Hz, 4H; H-
3
d), 7.44 (d, 1H; H-4’’), 7.42 (d, 1H; H-4), 7.25 (d, J=8.9 Hz, 6H; H-12),
3
3
7
.19 (d, J=8.9 Hz, 2H; H-10), 7.13 (d, J=8.9 Hz, 6H; H-11), 6.92 (d,
J=8.9 Hz, 2H; H-9), 6.30 (d, J=8.6 Hz, 4H; H-e), 5.29 (s, 2H; H-2),
Experimental Section
3
3
5
.19 (s, 2H; H-8), 4.14 (s, 2H; H-1), 3.92–3.86 (m, 4H; H-a), 3.79 (s, 4H;
General methods: Dry CH
the drying agent and dry CH
tive column chromatography was carried out by using silica gel (Merck
Kieselgel, silica gel 60, 0.063–0.200 mm).
2
Cl
2 3 2
and CHCl were distilled from CaH as
H-e), 3.81–3.70 (m, 12H; H-b, H-g, H-d), 1.29 ppm (s, 27H; H-13).
CN was purchased from Aldrich. Prepara-
II
I
3
Zn –[2]semirotaxane ([8]
A
H
U
G
R
N
U
G
): Same procedure as for Cu –[2]semiro-
2
]
2
+
taxane
(CH CN)
quantitatively as a yellow solid. H NMR (300 MHz, CD
8.87 (d, J=8.3 Hz, 2H; H-b), 8.83 (m, 1H; H-4’), 8.60–8.50 (m, 3H; H-3,
H-3’, H-5’), 8.38 (d, J=8.2 Hz, 1H; H-3’’), 8.32 (s, 2H; H-a), 8.32 (dd,
7
by using [Zn
A
H
U
G
R
N
N
(6.2 mg, 17 mmol) instead of [Cu-
II
A
H
U
G
R
N
U
G
3
4
]
A
H
U
G
R
N
U
G
6
1
NMR spectra were acquired on Bruker AVANCE 300, 400, or 500 spec-
, 258C): d=
3
trometers. The spectra were referenced to residual proton-solvent refer-
1
3
ences ( H, CD
2
Cl
2
at d=5.32 ppm, CDCl
3
at d=7.26 ppm, CD
3
CN at d=
3
4
1
.94 ppm). In the assignments, the chemical shift (in ppm) is given first,
J=8.2, J=1.4 Hz, 1H; H-4’’), 8.16 (dd, J=8.2, J=1.4 Hz, 1H; H-4),
8.07 (d, J=8.3 Hz, 2H; H-c), 8.06 (s, 1H; H-7), 7.79 (d, J=1.4 Hz, 1H;
3
followed, in brackets, by the multiplicity of the signal (s, singlet; d, dou-
blet; t, triplet; dd, doublet of doublets; m, multiplet), the value of the
4
H-6’’), 7.35 (d, J=1.4 Hz, 1H; H-6), 7.26 (d, J=8.8 Hz, 6H; H-12), 7.20
954
www.chemeurj.org
ꢂ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2011, 17, 947 – 957

Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites
FULL PAPER
3
3
3
(
8
d, J=8.8 Hz, 2H; H-10), 7.16 (d, J=8.8 Hz, 6H; H-11), 6.89 (d, J=
were subsequently evaporated to give a white residue. The desired com-
pound was directly characterized by NMR spectroscopy without any fur-
ther purification. The yield is quantitative according to the NMR spec-
3
3
.8 Hz, 2H; H-9), 6.86 (d, J=8.7 Hz, 4H; H-d), 6.23 (d, J=8.7 Hz, 4H;
H-e), 5.59 (s, 2H; H-2), 5.10 (s, 2H; H-8), 4.33 (s, 2H; H-1), 3.86–3.66
m, 20H; H-a, H-b, H-g, H-d, H-e), 1.29 ppm (s, 27H, H-13); MS (ES):
m/z (%): calcd for [C91
1
3
(
trum. H NMR (500 MHz, CD
2
Cl
2
, 258C): d=9.52 (d, J=8.9 Hz, 2H;
2
+
3
H
93
N
11
O
7
Zn] /2: 757.83; found: 758.75 (42)
H-1), 8.70 (d, J=9.0 Hz, 2H; H-2), 8.55 (m, 12H; H-3, H-4, H-5, H-7,
2
+
3
3
[
Mꢀ2OTf] /2.
H-b’), 8.46 (d, J=8.3 Hz, 4H; H-b), 8.38 (t, J=8.0 Hz, 2H; H-13), 8.10
(m, 4H; H-12, H-14), 8.03 (s, 4H; H-a’), 8.01 (s, 4H; H-a), 7.97 (m, 4H;
+
Demetalated [5]rotaxane (11): Terpyridinic [2]semirotaxane 7 (198 mg,
3
3
ꢀ
4
ꢀ5
I
H-9), 7.94 (d, J=8.1 Hz, 2H; H-15), 7.87 (d, J=8.2 Hz, 4H; H-c), 7.80
1
(
.19ꢄ10 mol), Na
33.6 mg, 1.86ꢄ10 mol), sodium ascorbate (14.6 mg, 7.37ꢄ10 mol),
and [3]pseudorotaxane 9 (76 mg, 3.9ꢄ10 mol) were introduced in dis-
tilled and degassed CH Cl (6 mL) and degassed anhydrous CH CN
3 mL). The mixture was stirred for 5 days and the solvents subsequently
evaporated. The resulting residue was then dissolved in a mixture of
2
5
CO
3
(3.9 mg, 3.7ꢄ10 mol), tren’-Br Cu catalyst
3
4
3
ꢀ
ꢀ5
(dd, J=8.3, J=2.1 Hz, 2H; H-16), 7.75 (d, J=8.2 Hz, 4H; H-c’), 7.59
4
3
2
+
ꢀ5
(m, 4H; H-10, H-19), 7.46 (d, J=1.7 Hz, 2H; H-17), 7.24 (d, J=8.7 Hz,
3
1
2H; H-24), 7.19 (d, J=9.0 Hz, 4H; H-22), 7.16 (s, 2H; H-6), 7.14 (d,
2
2
3
3
3
3
J=8.4 Hz, 8H; H-d), 7.13 (d, J=8.7 Hz, 12H; H-23), 7.04 (d, J=
(
3
3
8
.6 Hz, 8H), 6.91 (d, J=8.9 Hz, 4H; H-21), 6.11 (d, J=8.6 Hz, 8H; H-
3
ꢀ3
e), 6.07 (d, J=8.5 Hz, 8H; H-e’), 5.38 (s, 4H; H-8), 5.25 (s, 4H; H-18),
.16 (s, 4H; H-20), 3.95–3.60 (m, 80H; H-a, H-a’, H-b, H-b’, H-g, H-g’,
CH
was then added. The mixture was stirred for 4 h. Then, distilled water
20 mL) was added and this layer was extracted with CH Cl . The solvent
was then evaporated and the resulting brown residue was purified by alu-
2 2 3 2
Cl /CH CN/H O (2:1:1, 8 mL), and KCN (300 mg, 4.61ꢄ10 mol)
5
7
H-d, H-d’, H-e, H-e’), 1.28 ppm (s, 54H; H-25); Li NMR (500 MHz,
CD Cl , 258C): d=5.33, 4.63 ppm.
(
2
2
2
2
6
+
mina chromatography. A gradient of elution (CH
7:3) gave pure [5]rotaxane (130 mg, 2.94ꢄ10 mol, 75%). H NMR
400 MHz, CD
2
Cl
2
/MeOH 100:0 !
Li/Zn–[5]rotaxane (14 ): Demetalated [5]rotaxane 11 (7.7 mg, 1.7ꢄ
ꢀ5
1
ꢀ6
9
(
9
10 mol) was diluted with CH
2
Cl
2
(1 mL) and then a solution of LiBF
4
4
3
ꢀ6
2
Cl
2
, 258C): d=9.22 (d, J=1.7 Hz, 2H; H-5), 9.20 (d, J=
(0.45 mL, 0.36 mg, 3.8ꢄ10 mol) in MeOH with few drops of NEt
3
3
ꢀ3
ꢀ1
.1 Hz, 2H; H-1), 9.04 (s, 2H; H-7), 8.76 (d, J=8.5 Hz, 2H; H-2), 8.74
(8.53ꢄ10 molL ) and a solution of Zn
A
H
U
G
R
N
U
G
2
(1.9 mL, 1.28 mg, 3.52ꢄ
3
4
3
ꢀ6
ꢀ3
ꢀ1
(
d, J=8.4 Hz, 2H; H-3), 8.41 (d, J=1.8 Hz, 2H; H-9), 8.35 (dd, J=8.3,
10 mol) in MeOH (c=1.9ꢄ10 molL ) were added. The solution was
4
3
J=2.1 Hz, 2H; H-4), 8.32 (s, 2H; H-19), 8.31 (t, J=4.3 Hz, 2H; H-13),
stirred overnight and the solvents were evaporated. Heterodinuclear
3
ꢀ6
8
(
8
.26 (d, J=7.7 Hz, 2H; H-11), 8.25 (s, 2H; H-6), 8.25 (s, 2H; H-17), 8.24
[5]rotaxane was obtained in a quantitative yield (9.3 mg, 1.7ꢄ10 mol).
3
3
3
1
3
d, J=7.9 Hz, 2H; H-15), 8.11 (d, J=8.4 Hz, 4H; H-b’), 8.03 (d, J=
H NMR (500 MHz, CD
2
Cl
2
, 258C): d=9.55 (d, J=8.9 Hz, 2H; H-1),
3
3
3
3
.4 Hz, 4H; H-b), 7.94 (d, J=8.8 Hz, 8H; H-d’), 7.89 (d, J=8.8 Hz, 8H;
8.85 (t, J=7.9 Hz, 2H; H-13), 8.78 (d, J=8.4 Hz, 4H; H-b’), 8.73 (d,
3
3
H-d), 7.88–7.84 (m, 4H; H-12, H-14), 7.80 (d, J=8.3 Hz, 8H; H-c’), 7.74
J=8.9 Hz, 2H; H-2), 8.59 (s, 2H; H-7), 8.57–8.51 (m, 10H; H-b, H-3, H-
3
3
3
(
d, J=8.2 Hz, 8H; H-c), 7.66 (s, 4H; H-a’), 7.52 (s, 4H; H-a), 7.42 (dd,
4, H-5), 8.49 (d, J=7.6 Hz, 2H; H-14), 8.48 (d, J=7.7 Hz, 2H; H-12),
8.39 (d, J=8.5 Hz, 2H; H-15), 8.31 (d, J=8.4 Hz, 2H; H-11), 8.23 (m,
4H; H-10, H-16), 8.22 (s, 4H; H-a’), 8.02 (s, 4H; H-a), 7.97 (s, 2H; H-
3
4
3
4
3
3
J=8.4, J=2.1 Hz, 2H; H-10), 7.25 (dd, J=8.3, J=2.1 Hz, 2H; H-16),
.21 (d, J=8.6 Hz, 12H; H-24), 7.11 (d, J=8.7 Hz, 12H; H-23), 7.06 (d,
J=8.9 Hz, 4H; H-22), 6.89 (d, J=8.9 Hz, 4H; H-21), 6.64 (d, J=
.8 Hz, 8H; H-e’), 6.42 (d, J=8.7 Hz, 8H; H-e), 5.29 (s, 4H; H-8), 5.20
s, 4H; H-18), 5.06 (s, 4H; H-20), 3.90 (m, 8H; H-a’), 3.75 (t, J=6.1 Hz,
H; H-a), 3.67 (s, 8H; H-e), 3.60–3.40 (m, 56H; H-b, H-b’, H-g, H-g’, H-
d, H-d’, H-e’), 1.27 ppm (s, 56H; H-25); MS (ES): m/z: calcd for
3
3
7
3
3
3
3
3
19), 7.96 (d, J=8.6 Hz, 4H; H-c’), 7.87 (d, J=8.2 Hz, 4H; H-c), 7.64 (d,
3
4
4
3
8
(
8
J=1.6 Hz, 2H; H-17), 7.60 (d, J=1.5 Hz, 2H; H-9), 7.25 (d, J=8.6 Hz,
3
3
12H; H-24), 7.20 (d, J=8.9 Hz, 4H; H-22), 7.20 (s, 2H; H-6), 7.15 (d,
3
3
3
J=8.5 Hz, 12H; H-23), 7.15 (d, J=8.6 Hz, 8H; H-d), 6.93 (d, J=
3
3
8.9 Hz, 4H; H-21), 6.78 (d, J=8.7 Hz, 8H; H-d’), 6.18 (d, J=8.6 Hz,
8H; H-e’), 6.08 (d, J=8.5 Hz, 8H; H-e), 5.56 (s, 4H; H-8), 5.51 (s, 4H;
4
+
3+
3
[
[
C
C
276
276
H
H
268
268
N
N
30
30
O
O
26
H
4
]
/4: 1106.274, [C276
/3: 1482.023, [C276
H
H
268
N
30
O
26
H
3
]
/3: 1474.696,
/2: 2211.504;
3
+
2+
26NaH
2
]
268
N
30
O
26
H
2
]
H-18), 5.14 (s, 4H; H-20), 3.95–3.65 (m, 80H; H-a, H-a’, H-b, H-b’, H-g,
4
+
3+
7
found: 1106.265 [M+4H] /4, 1474.684 [M+3H] /3, 1482.012 [M
Na+2H] /3, 2211.541 [M+2H] /2.
H-g’, H-d, H-d’, H-e, H-e’), 1.29 ppm (s, 54H; H-25); Li NMR
3
+
2+
+
(500 MHz, CD
2 2
Cl , 258C): d=5.33 ppm.
8
+
Zn–[5]rotaxane (12 ): Demetalated [5]rotaxane 11 (6.3 mg, 1.4ꢄ
TMS axle (16): Anhydrous DMF (8 mL) and distilled NEt (1 mL) were
3
ꢀ
6
1
0
mol) was diluted in CH
in MeOH (3.4 mL, 6.3ꢄ10 mol; 1.86ꢄ10 molL ) was added. The so-
lution was stirred for 1 h and the solvents were subsequently evaporated.
2
Cl
2
(3 mL) and then a solution of Zn
A
H
U
G
R
N
U
G
2
introduced into an oven-dried flask. The mixture was degassed for
25 min with argon. Trimethylsilyacetylene (0.15 mL, 104 mg, 1.1ꢄ
ꢀ
6
ꢀ3
ꢀ1
ꢀ
3
ꢀ4
10 mol), compound 15 (99 mg, 2.0ꢄ10 mol), CuI (8.5 mg, 4.5ꢄ
ꢀ
5
ꢀ5
The resulting precipitate was then redissolved in CH
2
Cl
2
and filtered to
2 3 2
10 mol), and [PdCl AHCTUNRTGNEG(NU PPh ) ] (20 mg, 2.8ꢄ10 mol) were subsequently
get rid off the excess of inorganic salts. Metalated [5]rotaxane was thus
added. The solution was then heated up to 1008C under an argon atmos-
phere and then stirred for 2 h. The reaction mixture was cooled to room
temperature and the solvents evaporated. The product was purified by
alumina chromatography with chloroform. The product was then washed
with acetone, n-pentane, and diethyl ether. A beige powder was obtained
ꢀ
6
1
obtained (7.7 mg, 1.32ꢄ10 mol, 92%). H NMR (300 MHz, CD
3
CN,
3
3
2
8
8
58C): d=9.62 (d, J=9.0 Hz, 2H; H-1), 9.02 (d, J=8.4 Hz, 4H; H-b’),
.99 (d, J=8.3 Hz, 4H; H-b), 8.95 (dd, J=8.5, J=2.0 Hz, 2H; H-4),
3
3
4
.88–8.78 (m, 8H; H-2, H-3, H-12, H-14), 8.48–8.42 (m, 12H; H-13, H-15,
3
3
ꢀ5
1
H-a, H-a’), 8.38 (d, J=8.3 Hz, 2H; H-16), 8.37 (s, 2H; H-7), 8.34 (d, J=
(33 mg, 6.27ꢄ10 mol, 31%). M.p.
>
3008C; H NMR (300 MHz,
3
4
4
3
4
5
8
1
.3 Hz, 2H; H-11), 8.16 (dd, J=8.3, J=2.0 Hz, 2H; H-10), 8.14 (d, J=
.7 Hz, 2H; H-5), 8.11 (d, J=8.5 Hz, 4H; H-c’), 8.09 (d, J=8.4 Hz, 4H;
CDCl
3
, 258C): d=9.06 (d, J=8.8 Hz, 2H; H-1), 8.81 (dd, J=2.1, J=
3
3
3
3
5
0.6 Hz, 2H; H-5), 8.78 (d, J=8.6 Hz, 2H; H-2), 8.69 (dd, J=8.3, J=
4
4
3
4
H-c), 7.80 (s, 2H; H-19), 7.71 (d, J=1.4 Hz, 2H; H-9), 7.39 (d, J=
0.6 Hz, 2H; H-3), 8.32 (s, 2H; H-6), 7.95 (dd, J=8.2, J=2.0 Hz, 2H; H-
3
3
13
1
.4 Hz, 2H; H-17), 7.27 (d, J=8.6 Hz, 12H; H-24), 7.16 (d, J=9.0 Hz,
3
4), 0.31 ppm (s, 18H; H-TMS); C NMR (300 MHz, CDCl , 258C): d=
3
3
4
H; H-22), 7.12 (d, J=8.5 Hz, 12H; H-23), 7.04 (d, J=8.6 Hz, 8H; H-
155.62, 154.57, 152.11, 147.59, 139.83, 132.56, 131.73, 124.81, 120.82,
3
3
d), 6.95 (d, J=9.0 Hz, 4H; H-21), 6.80 (d, J=8.8 Hz, 8H; H-d’), 6.58
120.65, 119.64, 101.80, 99.63, ꢀ0.14 ppm; MS (ES): m/z: calcd
3
3
+
+
(
2H, s; H-6), 6.27 (d, J=8.5 Hz, 8H; H-e), 6.20 (d, J=8.6 Hz, 8H; H-
[C32
H
30
N
4
Si
2
+H] : 527.208, [C32
H
30
N
4
Si
2
+Li] : 533.217; found: 527.239
+
+
e’), 5.53 (4H, s; H-8), 5.40 (4H, s; H-18), 5.13 (4H, s; H-20), 3.90–3.55
[M+H] , 533.248 [M+Li] .
(
(
1
80H, m; H-a, H-a’, H-b, H-b’, H-g, H-g’, H-d, H-d’, H-e, H-e’), 1.26 ppm
4+
ꢀ5
Zn–[3]pseudorotaxane (17 ): Zn
CH
A
H
U
G
R
N
U
G
2
(6.9 mg, 1.9ꢄ10 mol) in
3
+
54H, s; H-25); MS (ES): m/z: calcd for [C276
268 30 4 5
H N O26Zn ACTHNTGURNENGU( OTf) ] /3:
3
ꢀ5
OH (1 mL) was added to a solution of macrocycle 5 (10.9 mg, 1.92ꢄ
Cl (2 mL). This solution was added to a solution of axle
2 2
6 (5.0 mg, 9.5ꢄ10 mol) in CH Cl (2 mL) and the mixture was reacted
4
+
809.178, [C276
H
268
N
30
O
26Zn
4
A
T
G
R
N
U
G
4
]
O
/4: 1319.146, [C276
H
268
N
30
O
26Zn
4
-
1
1
0
mol) in CH
5
+
6+
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(OTf)
3
]
/5: 1025.719, [C276
H
26Zn
4
A
H
U
G
R
N
U
G
2
]
/6: 830.113; found:
ꢀ6
2 2
3
+
4+
5+
1
809.176 [Mꢀ3OTf] /3, 1319.146 [Mꢀ4OTf] /4, 1025.719 [Mꢀ5OTf]
4+
overnight. After evaporation of the solvents, the [3]pseudorotaxane 17
6
+
/5, 830.106 [Mꢀ6OTf] /6.
ꢀ6
1
was obtained (22.2 mg, 9.30ꢄ10 mol, 98%). H NMR (300 MHz,
4
+
3
3
Li–[5]rotaxane (13 ): Demetalated [5]rotaxane 11 (6.7 mg, 1.5ꢄ
CD
2 2
Cl , 258C): d=9.67 (d, J=8.9 Hz, 2H; H-1), 8.93 (d, J=8.5 Hz,
ꢀ
ꢀ
6
3
3
1
1
0
0
mol) was dissolved in CH
2
Cl
2
(1 mL). A solution (1.4 mL, 1.2ꢄ
in MeOH
4H; H-b), 8.79 (d, J=9.0 Hz, 2H; H-2), 8.68 (d, J=8.4 Hz, 2H; H-3),
8.56 (dd, J=8.4, J=1.7 Hz; H-4), 8.36 (s, 4H; H-a), 8.25 (d, J=1.7 Hz,
2H; H-5), 8.05 (d, J=8.4 Hz, 4H; H-c), 7.07 (d, J=8.6 Hz, 8H; H-d),
5
3
4
4
mol) containing LiBF (8 mg) and two drops of NEt
4
3
3
3
(
10 mL) was added and the resulting solution stirred overnight. Solvents
Chem. Eur. J. 2011, 17, 947 – 957
ꢂ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
955

J.-P. Collin, S. Durot, J.-P. Sauvage et al.
3
6
.51 (s, 2H; H-6), 6.34 (d, J=8.8 Hz, 8H; H-e), 4.10–3.70 (m, 40H; H-a,
[23] L. Fang, M. A. Olson, D. Benitez, E. Tkatchouk, W. A. Goddard III,
J. F. Stoddart, Chem. Soc. Rev. 2010, 39, 17.
H-b, H-g, H-d, H-e), 0.30 ppm (s, 18H; H-TMS); MS (ES): the ESMS
spectrum of the complex could not be obtained; however, loss of a TMS
[24] A. Harada, A. Hashidzume, H. Yamaguchi, Y. Takashima, Chem.
Rev. 2009, 109, 5974.
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875.
2
+
group was observed: m/z (%): calcd: [C99
90 8 2 2 6
H N O18SiZn S F ] /2:
+
2
1
008.203; found: 1008.260 (100) [Mꢀ2OTfꢀTMS+H] /2; crystal data
ꢀ
for [17]
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
[TfO ]
4
: M=2492.20.91; pale-yellow plates/prisms; 0.10ꢄ0.40ꢄ
3
0
.40 mm ; monoclinic; space group P2
1
/c; a=13.8452(6), b=28.0649(14),
[26] F. Huang, H. W. Gibson, Progr. Polym. Sci. 2005, 30, 982.
3
c=30.6242(13) ꢃ; b=102.344(2)8; V=11624.4(9) ꢃ ; Z=4;
1
calcd
=
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ꢀ
3
ꢀ1
1
1
.424 gcm ; F000 =5152; m=2.190 mm ; T=123(2) K; 2qmax =127.08;
8823 reflections used, 11156 with I > 2s(I ), Rint =0.1769, 1402 parame-
>2s(I )], wR=0.4088 (all
o
o
ters, 36 restraints, GoF=1.451, R=0.1317 [I
o
o
3
reflections), 1.717<D1<ꢀ1.422 eꢃ .
[
[
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Chem. Eur. J. 2011, 17, 947 – 957
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