Self-assembly of novel [3]- and [2]rotaxanes based on donor-acceptor and hydrogen-bonding interactions. Intensified inter-ring repulsion interaction and shuttling behavior

Article abstract of DOI:10.1021/jo026370i

Three novel hetero [3]rotaxanes, which comprise one neutral tetraamide cyclophane, one tetracationic cyclophane, and one linear component, have been assembled by utilizing hydrogen-bonding and donor-acceptor interactions, through three neutral [2]rotaxane

Full text of DOI:10.1021/jo026370i

Self-Assem bly of Novel [3]- a n d [2]Rota xa n es Ba sed on
Don or -Accep tor a n d Hyd r ogen -Bon d in g In ter a ction s. In ten sified
In ter -Rin g Rep u lsion In ter a ction a n d Sh u ttlin g Beh a vior
Lin Chen,† Xin Zhao,‡ Yan Chen,† Cheng-Xue Zhao,† Xi-Kui J iang,‡ and Zhan-Ting Li*,‡
School of Chemistry and Chemical Engineering, Shanghai J iaotong University,
800 Dongchuan Lu, Shanghai 200240, China, and Shanghai Institute of Organic Chemistry,
Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China
ztli@pub.sioc.ac.cn.
Received August 30, 2002
Three novel hetero[3]rotaxanes, which comprise one neutral tetraamide cyclophane, one tetracationic
cyclophane, and one linear component, have been assembled by utilizing hydrogen-bonding and
donor-acceptor interactions, through three neutral [2]rotaxanes as intermediates. Three tetraca-
tionic [2]rotaxanes are also prepared for property comparison. For all three linear components,
diamide subunits, the hydrogen-bonding templating moieties, are introduced at the center of the
molecules, while the electron-rich hydrogquinone subunits, the donor-acceptor interaction
templates, are incorporated between the diamides and the triphenylmethyl stoppers. Compared
with the reported [3]rotaxanes, the novel hetero[3]rotaxanes exhibit remarkably intensified spatial
1
interaction between the two ring components, which had been proved by H NMR and UV study.
For the first time, inter-ring NOEs are observed for interlocked [3]rotaxanes.
In tr od u ction
along the linear component, which might be controlled
by chemical,4 electrochemical5 or optical exciting6 meth-
ods. However, these studies have always focused on the
interactions between the linear component and the cyclic
component(s). Probably as a result of the lack of suitable
model structures, to our knowledge, investigations on the
Rotaxanes are one class of supramolecular structures
that have been investigated vigorously in the past
decade.1 These supramolecules not only have exhibited
great potential for applications in smart molecular
devices and materials science but also are optimal
supramolecular platforms for investigating novel rules
of noncovalent interactions.2 With the progress of syn-
thetic supramolecular chemistry, several general and
efficient methods have been developed, and consequently
a large number of [2]rotaxanes and [3]rotaxanes have
been self-assembled.3 Many of the [2]rotaxanes display
the unique shuttling movement of the cyclic components
(3) For some recent examples, see: (a) Asakawa, M.; Ashton, P. R.;
Ballardini, R.; Balzani, V.; Belohradsky, M.; Gandolfi, M. T.; Kocian,
O.; Prodi, L.; Raymo, F. M.; Stoddart, J . F.; Venturi, M. J . Am. Chem.
Soc. 1997, 119, 302. (b) Gong, C.; Gibson, H. W. Angew. Chem., Int.
Ed. 1998, 37, 310. (c) Clegg, W.; Gimenez-Saiz, C.; Leigh, D. A.;
Mruphy, A.; Slawin, A. M. Z.; Teat, S. J . J . Am. Chem. Soc. 1999, 121,
4124. (d) Easton, C. J .; Lincoln, S. F.; Meyer, A. G.; Onagi, H. J . Chem.
Soc., Perkin Trans. 1 1999, 2501. (e) Fabicon, R. M.; Parvez, M.; Richey,
H. G., J r. Organometallics 1999, 18, 5163. (f) Baer, A. J .; Macartney,
D. H. Inorg. Chem. 2000, 39, 1410. (g) Chichak, K.; Walsh, M. C.;
Branda, N. R. Chem. Commun. 2000, 847. (h) Buston, J . E. H.; Young,
J . R.; Anderson, H. L. Chem. Commun. 2000, 905. (i) Loeb. S. J .;
Wisner, J . A. Chem. Commun. 2000, 1939. (j) J eppesen, J . O.; Perkins,
J .; Becher, J .; Stoddart, J . F. Org. Lett. 2000, 2, 3547. (k) Shukla, R.;
Deetz, M. J .; Smith, B. D. Chem. Commun. 2000, 2397. (l) Linke, M.;
Chambron, J .-C.; Heitz, V.; Sauvage, J .-P.; Encinas, S.; Barigelletti,
F.; Flamigni, L. J . Am. Chem. Soc. 2000, 122, 11834.
(4) (a) Bissell, R. A.; Co´rdova, E.; Kaifer, A. E.; Stoddart, J . F. Nature
1994, 369, 133. (b) Mart´ınez-D´ıaz, M.-V.; Spencer, N.; Stoddart, J . F.
Angew. Chem., Int. Ed. Engl. 1997, 36, 1904. (c) Ashton, P. R.;
Ballardini, R.; Balzani, V.; Baxter, I.; Credi, A.; Fyfe, M. C. T.; Gandolfi,
M. T.; Go´mez-Lo´pez, M.; Mart´ınez-D´ıaz, M.-V.; Piersanti, A.; Spencer,
N.; Stoddart, J . F.; Venturi, M.; White, A. J . P.; Williams, D. J . J . Am.
Chem. Soc. 1998, 120, 11932.
(5) (a) Armaroli, N.; Balzani, V.; Collin, J .-P.; Gavin˜a, P.; Sauvage,
J .-P.; Ventura, B. J . Am. Chem. Soc. 1999, 121, 4397. (b) Collin, J .-P.;
Dietrich-Buchecker, C.; Gavin˜a, P.; J imenez-Molero, M. C.; Sauvage,
J .-P. Acc. Chem. Res. 2001, 34, 477.
(6) (a) Ashton, P. R.; Ballardini, R.; Balzani, V.; Credi, A.; Dress,
K. R.; Ishow, E.; Kleverlaan, C. J .; Kocian, O.; Preece, J . A.; Spencer,
N.; Stoddart, J . F.; Venturi, M.; Wenger, S. Chem. Eur. J . 2000, 6,
3558. (b) Wurpel, G. W. H.; Brouwer, A. M.; van Stokkum, I. H. M.;
Farran, A.; Leigh, D. A. J . Am. Chem. Soc. 2001, 123, 11327. (c)
Brouwer, A. M.; Frochot, C.; Gatti, F. G.; Leigh, D. A.; Mottier, L.;
Paolucci, F.; Roffia, S.; Wurpel, G. W. Science 2001, 291, 2124.
† Shanghai J iaotong University.
‡ Shanghai Institute of Organic Chemistry.
(1) (a) Hoss, R.; Vo¨gtle, F. Angew. Chem., Int. Ed. Engl. 1994, 33,
375. (b) J ohnston, A. G.; Leigh, D. A.; Pritchard, R. J .; Deegan, M. D.
Angew. Chem., Int. Ed. Engl. 1995, 34, 1209. (c) Gibson, H. W. In Large
Ring Molecules; Semlyen, J . A., Eds.; J ohn Wiley & Sons: New York,
1996; pp 191-262. (d) Philp, D.; Stoddart, J . F. Angew. Chem., Int.
Ed. Engl. 1996, 35, 1155. (e) Catenanes, Rotaxanes and Knots; Sauvage,
J .-P., Dietrich-Buchecker, C. O., Eds.; Wiley-VCH: Weinheim, 1999.
(f) Lindoy, L. F.; Atkinson, I. M. Self-Asembly in Supramolecular
Systems; Royal Society of Chemistry: Cambridge, 2000. (g) Breault,
G. A.; Hunter, C. A.; Mayers, P. C. Tetrahedron 1999, 55, 5265. (h)
Raymo, F. M.; Stoddart, J . F. Chem. Rev. 1999, 99, 1643. (i) Hubin, T.
J .; Busch, D. H. Coord. Chem. Rev. 2000, 200, 5. (j) Reuter, C.;
Schmieder, R.; Vo¨gtle, F. Pure Appl. Chem. 2000, 72, 2233. (k) Cantrill,
S. J .; Pease, A. R.; Stoddart, J . F. J . Chem. Soc., Dalton Trans. 2000,
3715. (l) Mahan, E.; Gibson, H. W. In Cyclic Polymers; Semlyen, J . A.,
Ed.; Kluwer Publishers: Dordrecht, 2000; pp 415-560. (m) Raehm,
L.; Sauvage, J .-P. Struct. Bonding 2001, 99, 55.
(2) (a) Balzani, V.; Go´mez-Lo´pez, M.; Stoddart, J . F. Acc. Chem. Res.
1998, 31, 405. (b) Kaifer, A. E. Acc. Chem. Res. 1999, 32, 62. (c) Collier,
C. P.; Wong, E. W.; Belohradsky´, M.; Raymo, F. M.; Stoddart, J . F.;
Kuekes, P. J .; Williams, R. S.; Heath, J . R. Science 1999, 285, 391. (d)
Brouwer, A. M.; Frochot, C.; Gatti, F. G.; Leigh, D. A.; Mottier, L.;
Paolucci, F.; Roffia, S.; Wurpel, G. W. H. Science 2001, 291, 2124.
10.1021/jo026370i CCC: $25.00 © 2003 American Chemical Society
Published on Web 02/21/2003
2704
J . Org. Chem. 2003, 68, 2704-2712

Novel [3]- and [2]Rotaxanes
CHART 1
inter-ring interactions of more complex [3]rotaxanes have
never been reported, although such investigations are
potentially useful for exploring new principles to control
the relative orientation of components within supramol-
ecules and for further developing new generation of
supramolecular systems.
quinone subunits, to induce the generation of the tetra-
cationic macrocycle,9 are incorporated between the amides
and the stoppers. It is expected that, within the new
hetero[3]rotaxnes assembled based on them, the inter-
molecular hydrogen bonding between the neutral mac-
rocycle and the central amides of the linear compounds,
if any, would impose greater spatial repulsion on the
tetracationic cyclophane and consequently affect the
shuttling behavior of the tetracationic cyclophane along
the linear components, as shown in Figure 1.
We recently reported a general approach to assembling
hetero[3]rotaxane (1), which consists of a dipyridinium
tetracationic cyclophane, a neutral tetraamide cyclo-
phane, and a linear template, by combining the well-
established donor-acceptor interaction and intermolecu-
lar hydrogen-bonding principles.7 This novel type of
hetero[3]rotaxanes not only represents a new class of
rotaxane hybrids but also exhibits novel unique dynamic
properties, which are not available in homo[3]rotaxanes.
For example, the activation energy for the shuttling of
the tetracationic cyclophane along the linear component
was substantially lowered as a result of the presence of
the neutral cyclophane. Moreover, the autorotation of the
dipyridinium within the tetracationic cyclophane was
also revealed because of the asymmetry of the [3]-
rotaxanes. However, direct evidence could not be ob-
served for the possible spatial interaction between the
two different ring components. To more systematically
study this possible inter-ring interaction and also to
investigate the scope and limitation of the self-assembly
of this novel kind of [3]rotaxanes, we had designed a new
series of linear molecules, in which the hydrogen-bonding
templating subunits are incorporated between two hyd-
roquinone subunits at the center of the molecules. We
herein report the self-assembly of nine new hetero[3]-
rotaxanes and [2]rotaxanes from these linear templating
molecules and a detailed investigation of their dynamic
behavior.
F IGURE 1. Cartoon showing the inter-ring interactions
within the new hetero[3]rotaxanes. The neutral and tetraca-
tionic cyclophanes are represented by the hexagon and tet-
ragon, respectively.
Compound 10 was synthesized as described in Scheme
1. Compound 2 reacted with an excess of dibromide 3 in
refluxed acetonitrile in the presence of potassium carbon-
ate to afford bromide 4 in good yield, which further
coupled with phenol 5 to afford compound 6. Compound
6 was then hydrogenated in ethanol in the presence of
Pd-C to produce phenol 7 in quantitative yield. Com-
pound 7 was further converted to 8, which was hydro-
lyzed to afford 9. Compound 9 was then treated with
ethylenediamine in the presence of DCC and HOBt in
ethyl acetate to generate the first template, 10.
The synthesis of template compounds 14a and 14b is
shown in Scheme 2. Compound 4 was first alkylated with
bromide 11 to give compound 12, which was hydrolyzed
with hydrazine to produce amine 13. Treatment of
compound 13 with malonic acid or succinic acid in the
presence of DCC afforded compounds 14a and 14b,
respectively. For all three molecules 10, 14a , and 14b,
the triphenylmethylphenol group was chosen as the
stopper for its synthetic convenience.
Resu lts a n d Discu ssion
Syn th esis a n d Self-Assem bly. Three linear tem-
plates, 10, 14a , and 14b, were designed and synthesized.
Different from the previously reported templates, in
which the glycine moieties are directly connected to the
stoppers,7 all three compounds 10, 14a , and 14b are
incorporated with two unnatural amide moieties as
hydrogen-bonding assembling templates at the center of
the molecules. In addition, the two amide moieties are
connected by very short aliphatic linkers, to facilitate
their ability to cooperatively template the formation of
the neutral tetraamide cyclophane,8 and two hydro-
Two [2]rotaxanes and one [3]rotaxane were then as-
sembled from the template molecule 10, as shown in
Scheme 3. Thus, treatment of compound 10 with dica-
tionic salt 15‚2PF6 and dibromide 16 in DMF at room
temperature for 10 days afforded tetracationic [2]rotax-
ane 17‚4Cl in 34% yield after column chromatography,
whereas the reaction of 1,3-phthaloyl dichloride 18 and
diamine 19 in chloroform in the presence of 10 at room
(9) Anelli, P. L.; Ashton, P. R.; Ballardini, R.; Balzani, V.; Delgado,
M.; Gandolfi, M. T.; Goodnow, T. T.; Kaifer, A. E.; Philp, D.; Pietrasz-
kiewicz, M.; Prodi, L.; Redington, M. V.; Slawin, A. M. Z.; Spencer, N.;
Stoddart, J . F.; Vicent, C.; Williams, D. J . J . Am. Chem. Soc. 1992,
114, 193.
(7) Zhao, X.; J iang, X.-K., Shi, S.; Yu, Y.-H.; Xia, W.; Li, Z.-T. J .
Org. Chem. 2001, 66, 7035.
(8) J ohnston, A. G.; Leigh, D. A.; Nezhat, L.; Smart, J . P.; Deegan,
M. D. Angew. Chem., Int. Ed. Engl. 1995, 34, 1212.
J . Org. Chem, Vol. 68, No. 7, 2003 2705

Chen et al.
SCHEME 1
SCHEME 2
temperature led to the formation of neutral [2]rotaxane
20 in 24% yield. In the presence of [2]rotaxane 20, the
reaction of 15‚2PF6 with 16 in DMF at room temperature
for 10 days gave the hetero[3]rotaxane 21‚4Cl in 31%
yield.
With compounds 14a and 14b as templates, the
reactions of dication 15‚2PF6 with dibromide 16 in DMF
gave another two ionic [2]rotaxanes 22a ‚4Cl and 22b‚
4Cl, and the reactions of compound 18 with diamine 19
afforded neutral [2]rotaxanes 23a and 23b, respectively.
These two neutral [2]rotaxanes were further utilized as
templates to assemble tetracationic [3]rotaxanes 24a ‚4Cl
and 24b‚4Cl after column chromatography, as shown in
Scheme 4.
For all reactions to assemble [3]rotaxanes, no [4]-
rotaxanes with two tetracationic rings were detected. It
was reported that the ability of amide derivatives to
template the formation of [2]rotaxanes varies greatly
depending on their structures.8,10 The present three linear
compounds 10 and 14a ,b exhibit comparable templating
ability, although the incorporated amide subunits are
quite different. As had been observed in a previous
report,7 the assembly yields of all of the hetero[3]-
rotaxanes are higher than those for the neutral [2]-
rotaxanes.
1H NMR Sp ectr oscop y a n d Sh u ttlin g P r op er ties.
The structures of the [2]- and [3]rotaxanes have been
characterized by 1H NMR and MS spectra and elemental
analysis. Significant upfield shifts were observed for
aliphatic protons of the linear part of all rotaxanes as a
result of the shielding of the ring components. The shut-
tling properties of the three tetracationic [2]rotaxanes
were first investigated by variable temperature 1H NMR,
and the activation energies for the shuttling processes
of the ionic cyclophane between the hydroquinone sta-
tions, obtained with the coalescence method,11 are listed
in Table 1. It can be seen that the values for these new
[2]rotaxanes are comparable to those of the previously
reported [2]rotaxanes,7,12 in which two hydroquinone
subunits are connected with a tetra(ethyleneoxyl) chain
in the linear components. The results reveal that in
(11) Sandstroom, J . In Dynamic NMR Spectroscopy; Academic
Press: New York, 1982; Chapter 6.
(12) Anelli, P.-L.; Asakawa, M.; Ashton, P. R.; Bissell, R. A.; Clavier,
G.; Go´rski, R.; Kaifer, A. E.; Langford, S. J .; Mattersteig, G.; Menzer,
S.; Philp, D.; Slawin, A. M. Z.; Spencer, N.; Stoddart, J . F.; Tolley, M.
S.; Williams, D. J . Chem. Eur. J . 1997, 3, 1113.
(10) Gatti, F. G.; Leigh, D. A.; Nepogodiev, S. A.; Slawin, A. M. Z.;
Teat, S. J .; Wong, J . K. Y. J . Am. Chem. Soc. 2001, 123, 5983.
2706 J . Org. Chem., Vol. 68, No. 7, 2003

Novel [3]- and [2]Rotaxanes
SCHEME 3
highly polar solvents, there are no substantial interaction
between the tetracationic cyclophane and the centrally
located amide moieties of the linear components.
show NOEs between the ring and linear components for
the three neutral [2]rotaxanes. This observation is quite
different from that reported by Leigh13 and may be
attributed to the existence of many ethyleneoxyl groups
in the linear components. These ethylene-linked oxygens
may compete with the CO oxygens in the linear compo-
nents to bind the NH protons in the ring component by
hydrogen bonding, making it impossible for selective
positioning of the ring component around the central
amide subunits.
Within the temperature range from 210 to 298 K, no
shuttling behavior was observed for neutral [2]rotaxanes
20, 23a , and 23b in chloroform-d. This may be attributed
to the fact that the two amides in all three linear
components are very close and the macrocyclic component
may be positioned in a conformation such as to be able
to form hydrogen bonds with both amides of the linear
molecules simultaneously, which means that there is
actually no shuttling behavior of the cyclophane between
the two amide stations.13 Since no further splitting was
observed for all the proton signals of the cyclophane in
[2]rotaxanes 20, 23a , and 23b within the above temper-
ature range, the two chairlike conformations observed
in the solid-state structures of several related [2]rotax-
anes should, if any, undergo fast exchange on the 1H
NMR time scale.10 2D-NOESY and COSY spectra did not
[3]Rotaxanes 21‚4Cl, 24a ‚4Cl, and 24b‚4Cl are asym-
metric because they comprise two different rings and
1
therefore display much more complicated H NMR spec-
tra. The 1H NMR signals of these [3]rotaxanes have been
assigned on the basis of 2D-NOESY and COSY tech-
niques. The methylene protons of the neutral rings of all
three [3]rotaxanes exhibit two sets of doublets. However,
the xylene protons give only one singlet even at the low
temperature of 210 K, showing that the benzenes always
rotate quickly around the methylenes-built axis on the
1H NMR time scale. Generally, NOEs were observed
between both R- and â-protons of the cyclophane pyri-
(13) (a) Lane, A. S.; Leigh, D. A.; Murphy, A. J . Am. Chem. Soc.
1997, 119, 11092. (b) Leigh, D. A.; Murphy, A.; Smart, J . P.; Slawin,
A. M. Z. Angew. Chem., Int. Ed. Engl. 1997, 36, 728.
J . Org. Chem, Vol. 68, No. 7, 2003 2707

Chen et al.
SCHEME 4
TABLE 1. Kin etic a n d Th er m od yn a m ic P a r a m eter s of
Ion ic [2]Rota xa n es in Meth a n ol-d Ba sed on th e
Tem p er a tu r e-Dep en d en t 1H NMR Meth od
∆ν
kc
Tc
rotaxanes probe
(Hz)a
(s-1
)
(K)b ∆Gq (kcal-1 mol-1
)
17‚4Cl
R-CHc 51 ( 4 113 ( 9
268
268
13.1 ( 0.2
13.1 ( 0.2
13.1 ( 0.2
13.1 ( 0.2
12.9 ( 0.2
17‚4Cl
â-CHd 58 ( 4 129 ( 9
22a ‚4Cl
22b‚4Cl
22b‚4Cl
R-CH 53 ( 5 117 ( 11 268
R-CHc 56 ( 4 124 ( 9
â-CHd 40 ( 4 189 ( 9
268
263
a
The errors represent the deviations from the average values
of three experiments. With an error of (5 °C. c CH R to the
b
F IGURE 2. NOEs observed between the protons of the two
ring components of [3]rotaxanes 21‚4Cl. The linear component
is represented by cartoon for clarity.
d
pyridine N of the tetracationic ring. CH â to the pyridine N of
the tetracationic ring.
diniums and many ethyleneoxy protons of the linear
components in methanol-d. A number of NOEs were also
detected between the neutral and ionic ring components,
and the results obtained for [3]rotaxanes 21‚4Cl is
presented in Figure 2 as an example. This observation
provides direct evidence to support that there are sig-
nificant spatial repulsion between the two ring compo-
nents. To our knowledge, this is the first observation of
inter-ring NOEs for [3]rotaxanes. In principle, spatial
repulsion always exists between ring components of
[3]rotaxanes. However, such spatial interaction could
not be measured by the NOE technique for homo[3]-
rotaxanes, since it is impossible to determine if such
possible NOEs come from intra-ring or inter-ring interac-
tions for homo[3]rotaxanes. It is noteworthy that no
similar NOEs had ever detected for previously reported
hetero[3]rotaxanes.7 Therefore, this observation indicates
that inter-ring interaction could be improved by simple
2708 J . Org. Chem., Vol. 68, No. 7, 2003

Novel [3]- and [2]Rotaxanes
TABLE 3. Da ta Associa ted w ith [3]Rota xa n es
Associa ted w ith Sh u ttlin g Beh a vior of Tetr a ca tion ic
Cyclop h a n e in [3]Rota xa n es in Meth a n ol-d , Ba sed on th e
1H NMR Meth od
∆ν
kc
Tc
rotaxanes probea
(Hz)b
(s-1
)
(K)c ∆Gq (kcal-1 mol-1
)
21‚4Cl
R-CH 216 ( 10 477 ( 22 288
â-CH 204 ( 12 452 ( 26 275
R-CH 251 ( 12 556 ( 26 283
â-CH 250 ( 15 553 ( 30 288
R-CH 229 ( 20 506 ( 44 278
â-CH 258 ( 14 571 ( 31 283
13.3 ( 0.1
12.7 ( 0.1
13.0 ( 0.1
13.2 ( 0.2
12.8 ( 0.2
12.9 ( 0.1
21‚4Cl
24a ‚4Cl
24a ‚4Cl
24b‚4Cl
24b‚4Cl
a
b
The pyridine CHs of the tetracationic ring. The errors
represent the deviations from the average values of three experi-
ments. c With an error of (5 °C.
shuttling process of the ionic cyclophane are fast on the
NMR time scale. With the lowering of the temperature,
these signals gradually split into two and then four
separated signals. This observation may be rationalized
by considering that the corresponding rotation and
shuttling processes mentioned above are lowered and
finally stopped on the NMR time scale at reduced
temperature. On the basis of the previously reported
work,7 the second splitting process was ascribed as the
result of the shuttling process of the tetracationic cyclo-
phane. The free energies of activation associated with this
shuttling process of the [3]rotaxanes can be derived with
the coalescence method and are presented in Table 3.15
Considering the error of the coalescence method, the
values are actually comparable, showing that the change
of the center-positioned amides have no substantial effect
on the shuttling process. The results also support the
opinion that, as had been observed in several related
hetero[3]rotaxanes,7 the neutral cyclophane in these new
hetero[3]rotaxanes also always imposed repelling on the
tetracationic cyclophane and remarkably affected the
later’s shuttling behavior as shown in Figure 1.
F IGURE 3. Partial variable temperature 1H NMR spectra
(400 HMz, DMSO-d6) of 24b‚4Cl at (a) 293, (b) 303, (c) 313,
(d) 323, (e) 333 K, and (f) 343 K, showing that the separated
signals gradually combine to afford a new singlet for both R-
and â-pyridinium protons.
TABLE 2. Kin etic a n d Th er m od yn a m ic P a r a m eter s for
Rota tion of Dip yr id in iu m Un its a r ou n d th e
Meth ylen es-Bu ilt Axis in [3]Rota xa n es in DMSO-d 6,
Ba sed on 1H NMR Sp ectr a
∆ν
kc
Tc
rotaxane probea
(Hz)b
(s-1
)
(K)c ∆Gq (kcal-1 mol-1
)
21‚4Cl
21‚4Cl
R-CH 117 ( 10 259 ( 22 335
â-CH 132 ( 6 293 ( 13 340
16.0 ( 0.3
16.2 ( 0.2
15.8 ( 0.2
15.7 ( 0.2
15.8 ( 0.1
16.0 ( 0.1
24a ‚4Cl R-CH 136 ( 8 301 ( 18 333
24a ‚4Cl â-CH
82 ( 8 182 ( 18 325
24b‚4Cl R-CH 156 ( 5 346 ( 11 333
24b‚4Cl â-CH
72 ( 5 160 ( 11 328
a
b
The pyridine CHs of the tetracationic ring. The errors
represent the deviations from the average values of three experi-
ments. c With an error of (5 °C.
re-location of the templating moieties of the linear
components.
Electr on ic Absor p tion Sp ectr a . The UV-vis prop-
erties of all of the linear compounds, [2]- and [3]rotax-
anes, were investigated in methanol. A summary of the
absorption data is presented in Table 4. The absorption
bands observed for 10, 14a , and 14b, all with maxima
at 286 nm, are ascribed to the hydroquinone units.
Similar absorption bands are also observed for the
neutral [2]rotaxanes 20, 23a , and 23b with the same
absorption maxima, indicating that the neutral cyclo-
phane in these [2]rotaxanes have no significant influence
on the electronic property of the hydroquinone units. As
expected, intense charge-transfer absorption bands were
observed for all the ionic [2]- and [3]rotaxanes, as s result
of the donor-acceptor interaction between the bipyri-
dinium and hydroquinone units.7,9
At room temperature, both the R- and â-protons of the
dipyridiniums of the tetracationic cyclophane of all [3]-
rotaxanes 21‚4Cl, 24a ‚4Cl, and 24b‚4Cl in DMSO-d6
display two separated signals, indicating that the rotation
of the dipyridinium subunits around the axis of the two
1
linked methylene groups are slow on the H NMR time
scale.7 With the increase of the temperature, both R- and
â-proton signals gradually combine and generate a new
broad signal, respectively, as shown in Figure 3 for 24b‚
4Cl. The values of the activation energy ∆Gq for this
rotating processed are obtained by using the coalescence
method and are presented in Table 2.14
Variable temperature 1H NMR study reveals that
hetero[3]rotaxanes 21‚4Cl, 24a ‚4Cl, and 24b‚4Cl also
display significant temperature dependence at reduced
temperature. For example, both the R- and â-pyridinium
protons of 24b‚4Cl exhibit a broad signal, respectively,
in methanol-d at room temperature, indicating that both
the rotation of the pyridiniums described above and the
It is found that the values of the [3]rotaxanes are
obviously reduced compared with those of reported [3]-
rotaxanes (1),7 in which the amide subunits are incor-
porated between the center-positioned hydroquinone
(15) In principle, the populations of the two exchange states of the
tetracationic cyclophane may be different in these new hetero[3]-
rotaxanes as a result of the repelling effect of the neutral cyclophane
in these hetero[3]rotaxanes. However, no quantitative results could
be obtained from these and previously reported (see ref 7) hetero[3]-
rotaxanes because of the reduced resolution of their 1H NMR at low
temperature. We thank one of the referees for reminding us to pay
more attention to this point.
(14) A series of [2]rotaxanes had been reported in which the
dipyridinium units rotate around their nitrogen-nitrogen axis as a
result of the different environments imposed by the 1,5-dioxynaph-
thalene unit in the linear components: Bravo, J . A.; Raymo, F. M.;
Stoddart, J . F.; White, A. J . P.; Williams, D. J . Eur. J . Org. Chem.
1998, 2565. We thank one of the referees for reminding us of this work.
J . Org. Chem, Vol. 68, No. 7, 2003 2709

Chen et al.
TABLE 4. Ma xim u m a n d Ch a r ge-Tr a n sfer Absor p tion s of Tem p la tes a n d Rota xa n es, Recor d ed in Meth a n ol a t Am bien t
Tem p er a tu r e
compounds
λmax (nm)
log ꢀ (M-1 cm-1
)
compounds
λmax (nm)
log ꢀ (M-1 cm-1
)
λCT (nm)
log ꢀ (M-1 cm-1
)
10
286
286
286
287
286
286
3.85
3.83
3.92
4.06
3.96
3.91
17‚4Cl
262
263
263
263
263
263
4.46
4.24
4.46
4.44
4.47
4.37
462
467
465
464
464
468
2.59
2.58
2.60
2.42
2.45
2.34
14a
14b
20
23a
23b
22a ‚4Cl
22b‚4Cl
21‚4Cl
24a ‚4Cl
24b‚4Cl
was added dibromide 317 (6.63 g, 240 mmol). The mixture was
then refluxed for 48 h and the solid was filtered off. The
solution was concentrated and the remaining residue tritu-
rated in dichloromethane (300 mL). The solution was washed
with water (2 × 50 mL) and brine (100 mL) and dried over
sodium sulfate. After the solvent was removed, the residue
was chromatographed (ethyl acetate/light petroleum, 1:4), to
afford compound 4 as a white solid (7.32 g, 46%). Mp: 106-
subunits and the stoppers. Moreover, it can also be found
that the values for all the [3]rotaxanes are remarkably
lower than those of [2]rotaxaens. These results also
support that greater spatial repulsions are imposed upon
the tetracationic cyclophane by the neutral cyclophane
in the present [3]rotaxanes, which lead to decreased
donor-acceptor interaction between the pyridinium and
hydroquinone subunits.
1
107 °C [lit. 102-104 °C18]. H NMR (CDCl3): δ 7.27-7.18 (m,
15 H), 7.10 (m, 2 H), 6.80 (m, 2 H), 4.12 (m, 2 H), 3.87-3.79
(m, 4 H), 3.71 (m, 4 H), 3.46 (t, 2 H, J ) 6.3 Hz). MS (EI): m/z
530 [M]+.
Lu m in escen ce P r op er ties. Irradiation of the maxi-
mum absorption bands at 287 nm for the three linear
molecules 10, 14a , and 14b leads to emission bands with
maximum at 325 nm. With the same irradiation light,
emission bands are observed for neutral [2]rotaxanes 20,
23a , and 23b at 326, 325, and 327 nm. However, the
emission intensity of the [2]rotaxanes is remarkably
reduced (50%) compared with that of the corresponding
linear precursor molecules under the same measurement
conditions. This quenching effect may be attributed to
the result of weak interaction between the excited
hydroquinone and the neutral cyclophane. Under similar
conditions, no emission is detected for the hydroquinone
subunits of the ionic [2]- and [3]rotaxanes because of the
efficient quenching of the charge-transfer interactions.7,9
In summary, we have reported self-assembly and
characterization of three novel hetero[3]rotaxanes, con-
sisting of neutral and tetracationic ring components, by
utilizing both intermolecular hydrogen bonding and
donor-acceptor interactions. The dynamic investigation
reveals that the spatial interaction between the neutral
and cationic ring components of these [3]rotaxanes has
been substantially increased as a result of simple reloca-
tion of the amides subunits to the central part of the
linear components, which have been proved by first direct
observations of NOEs between the two ring components
and the reduced donor-acceptor interaction within the
[3]rotaxanes. We are now using different noncovalent
assembling principles to construct new functional su-
pramolecular hybrids, which will be reported in due
course.
Com p ou n d 6. A suspension of compound 4 (4.70 g, 8.87
mmol), 4-benzoxyphenol 5 (1.80 g, 8.90 mmol), and K2CO3 (11.4
g, 82.6 mmol) in acetonitrile (150 mL) was refluxed for 24 h.
After cooling to room temperature, the solid was filtered off
and the solvent was removed. The resulting residue was
worked up in a normal way and then purified by column
chromatography (EtOAc/light petroleum ether, 1:3). Compound
6 was obtained as a white solid (4.48 g, 78%). Mp: 84-85 °C.
1H NMR (CDCl3): δ 7.43-7.37 (m, 6 H), 7.30-7.19 (m, 18 H),
7.11 (m, 2 H), 6.89-6.80 (m, 6 H), 5.02 (s, 2 H), 4.11 (m, 4 H),
3.86 (m, 4 H), 3.77 (m, 4 H). MS (EI): m/z 650 [M]+. Anal.
Calcd for C44H42O5: C, 81.20; H, 6.50. Found: C, 80.74; H,
6.31.
Com p ou n d 7. Compound 6 (5.90 g, 9.08 mmol) was
dissolved in methanol/methylene chloride (100 mL, 4:1), and
10% Pd-C (0.12 g) was added. The resulting mixture is stirred
with bubbling of hydrogen at a pressure of 16 psi for 5 h. The
catalyst was then filtered off, and the solvent was evaporated
in vacuo. The crude product is purified by flash column
chromatography (chloroform/methanol, 10:1). Compound 7
(4.88 g) was obtained as a white solid in 96% yield, which is
1
recrystallized from methanol for analysis. Mp: 96-97 °C. H
NMR (CDCl3): δ 7.25-7.20 (m, 15 H), 7.17 (m, 2 H), 6.78-
6.71 (m, 6 H), 4.7 (b, 1 H), 4.07 (m, 4 H), 3.84 (m, 4 H), 3.80
(m, 4 H). MS (EI): m/z 560 [M]+. Anal. Calcd for C37H36O5: C,
79.26; H, 6.47. Found: C, 79.18; H, 6.51.
Com p ou n d 8. A suspension of phenol 7 (4.48 g, 8.00 mmol),
methyl 4-bromobutyrate (1.44 g, 8.00 mmol), and potassium
carbonate (2.24 g, 16.0 mmol) in acetonitrile (250 mL) was
heated under reflux for 48 h. After cooling to room tempera-
ture, the reaction mixture was filtered. The filtrate was
concentrated and the resulting residue was triturated with
methylene chloride (300 mL). The resulting organic phase was
washed with 2 M sodium carbonate solution (2 × 60 mL),
water (60 mL), and brine (60 mL) and dried over sodium
sulfate. After the solvent was removed under reduced pressure,
the resulting residue was purified by chromatography (ethyl
acetate/hexane, 2:3). Compound 8 was obtained as a white
solid (3.44 g, 65%). Mp: 103-105 °C. 1H NMR (CDCl3): δ
7.15-7.26 (m, 15 H), 7.09 (d, 2 H), 6.77-6.85 (m, 6 H), 4.05-
4.12 (m, 4 H), 3.93 (t, 2 H, J ) 6.0 Hz), 3.81-3.86 (m, 4 H),
3.74 (s, 4 H), 3.68 (s, 3 H), 2.51 (t, 2 H; J ) 7.2 Hz), 2.05-2.10
(m, 2 H). MS (EI): m/z 660 [M]+. Anal. Calcd for C42H44O7: C,
76.34; H, 6.71. Found: C, 76.10; H, 6.75.
Exp er im en ta l Section
Meth od s a n d Ma ter ia ls. Melting points are uncorrected.
1H NMR spectra were recorded on a 400 or 300 MHz spec-
trometer with Me4Si as internal standard. Mass spectra were
recorded in EI or ESI mode. Elemental analysis was carried
out at the SIOC analytical center. Absorption spectra were
recorded 20 °C. Fluorescence spectra were obtained at 20 °C.
Unless stated otherwise, all reagents were obtained from
commercial sources and used without further purification. The
solvents have been purified by standard procedures before use.
Silica gel was used for column chromatography. All reactions
were carried out under an atmosphere of nitrogen.
Com p ou n d 9. This compound was obtained quantitatively
as a white solid by hydrolysis of compound 9 with sodium
Com p ou n d 4. To a suspension of phenol 216 (10.0 g, 10.0
mmol) and K2CO3 (16.6 g, 40.0 mmol) in acetonitrile (150 mL)
(17) Hammond, P. J .; Bell, A. P.; Hall, C. D. J . Chem. Soc., Perkin
Trans. 1 1983, 707.
(18) Li, Z.-T.; Stein, P. C.; Becher, J .; J ensen, D.; Mørk, P.;
Svenstrup, N. Chem. Eur. J . 1996, 2, 624.
(16) Hart, C. J . Am. Chem. Soc. 1954, 76, 1634.
2710 J . Org. Chem., Vol. 68, No. 7, 2003

Novel [3]- and [2]Rotaxanes
hydroxide in aqueous THF at room temperature. Mp: 79-81
°C. 1H NMR (CDCl3): δ 7.17-7.27 (m, 15 H), 7.09 (d, 2 H),
6.77-6.85 (m, 6 H), 4.05-4.11 (m, 4 H), 3.94 (t, 2 H, J ) 6.0
Hz), 3.82-3.86 (m, 4 H), 3.74 (s, 4 H), 2.56 (t, 2 H; J ) 7.2
Hz), 2.05-2.10 (m, 2 H). MS (EI): m/z 646 [M]+. Anal. Calcd
for C41H42O7: C, 76.14; H, 6.55. Found: C, 75.89; H, 6.50.
Com p ou n d 10. A solution of DCC (0.89 g, 4.3 mmol), HOBt
(0.58 g, 4.3 mmol), compound 9 (2.80 g, 4.30 mmol), and
ethylenediamine (0.13 g, 2.2 mmol) in chloroform (150 mL)
was stirred at 0 °C for 24 h. The solid was filtered off and the
filtrate evaporated to give a solid residue. After workup, the
resulting residue was purified by chromatography (methylene
chloride/ethanol, 20:1) to give compound 10 (2.38 g, 81%) as a
white powder. Mp: 112-114 °C. 1H NMR (CDCl3): δ 7.31-
7.19 (m, 30 H), 7.10-7.07 (m, 4 H), 6.80-6.86 (m, 12 H), 6.25
(br, 2 H), 4.05-4.10 (m, 8 H), 3.83-3.89 (m, 12 H), 3.73 (m, 8
H), 3.36 (s, 4 H), 2.34 (s, 4 H), 2.05 (s, 4 H). MS (ESI): m/z
1340 [M + Na]+. Anal. Calcd for C84H88N2O12: C, 76.57; H,
6.73; N, 2.13. Found: C, 76.12; H, 6.46; N, 2.22.
Com p ou n d 12. This compound was prepared as a white
solid in 94% yield from the reaction of phenol 4 and N-(3-
bromopropyl) phthalimide 1119 according to the procedure
described above for preparing compound 12. Mp: 41-42 °C.
1H NMR (CDCl3): δ 7.84 (m, 2 H), 7.71 (m, 2 H), 7.28-7.19
(m, 15 H), 7.09 (m, 2 H), 6.80 (m, 2 H), 6.79 (d, 2 H), 6.72 (m,
2 H), 4.08 (m, 4 H), 3.96 (m, 2 H), 3.87 (m, 4 H), 3.83 (m, 2 H),
3.74 (m, 4 H), 2.15 (m, 2 H). MS (EI): m/z 747 [M]+. Anal.
Calcd for C48H45NO7: C, 77.09; H, 6.06; N, 1.87. Found: C,
76.70; H, 6.19; N, 2.14.
further by recrystallization from MeOH. Mp: 204-208 °C
(dec). 1H NMR (CD3OD): δ 9.28 (s, 8 H,), 8.23 (s, 8 H), 7.93 (s,
8 H), 6.92-7.20 (m, 34 H), 6.40-6.78 (m, 8 H), 5.82 (s, 8 H),
3.30-4.07 (m, 28 H), 2.50 (m, 4 H), 2.07 (m, 4 H), 1.29 (s, 4
H). MS (ESI): m/z 955 [M - 2Cl]2+, 1285 [2M - 3Cl]3+. Anal.
Calcd for C120H120Cl4N6O12: C, 72.79; H, 6.11; N, 4.24. Found:
C, 72.41; H, 6.09; N, 4.18.
[2]Rota xa n e 20. To a stirred solution of compound 10 (1.32
g, 1.00 mmol) and triethylamine (2.76 mL, 20.0 mmol) in
chloroform (50 mL) were added with stirring a solution of
m-phthaloyl dicholoride 18 (0.20 g, 1.00 mmol) in chloroform
(50 mL) and a solution of p-xylylene diamine 19 (0.14 g, 1.00
mmol) in chloroform (50 mL) at room temperature simulta-
neously over 5 h. The mixture was then stirred at room
temperature for another 12 h. The solid was filtered off. The
filtrate was washed with 1 N HCl solution (3 × 10 mL), 5%
NaHCO3 solution (3 × 10 mL), water (10 mL), and brine (10
mL) and then dried over sodium sulfate. The solvent was
evaporated in vacuo, and the resulting residue was purified
by flash chromatography (CHCl3/MeOH, 20:1). [2]Rotaxane 20
(0.63 g, 34%) was obtained as a white solid. Mp: 144-145 °C.
1H NMR (CDCl3): δ 8.16 (s, 2 H), 8.07 (d, 4 H, J ) 7.5 Hz),
7.56 (br, 4 H), 7.47 (t, 2 H, J ) 7.5 Hz), 7.27-7.14 (m, 40 H),
7.05 (d, 2 H, J ) 8.7 Hz), 6.71-6.52 (m, 12 H), 4.50 (s, 8 H),
3.97-3.99 (m, 8 H), 3.73-3.69 (s, 20 H), 3.10 (s, 4 H), 1.95 (s,
4 H), 1.69 (s, 4 H). Anal. Calcd for C115H114N6O16‚H2O: C,
74.49; H, 6.31; N, 4.53. Found: C, 74.79; H, 6.74; N, 4.38.
[3]Rota xa n e 21‚4Cl. This [3]rotaxane was prepared in 31%
yield as a red solid from the reaction of compounds 15‚2PF6
and 16 in the presence of [2]rotaxane 20 by using a similar
procedure as described for preparing 17‚4Cl. Mp: 220-225
°C (decom.). 1H NMR (DMSO-d6): δ 9.91 (s, 4 H), 9.85 (s, 4
H), 9.62 (s, 4 H), 8.83 (s, 4 H), 8.50 (s, 4 H), 8.16 (s, 2 H), 8.11
(m, 4 H), 8.03 (s, 8 H), 7.64 (m, 2 H), 6.78-7.34 (m, 50 H),
5.85-6.06 (m, 8 H), 4.92-4.97 (m, 4 H), 4.24-4.27 (m, 4 H),
3.30-4.03 (m, 28 H), 2.87-3.01 (m, 4 H), 2.30 (s, 4 H), 2.12 (s,
4 H), 1.91 (s, 4 H). MS (ESI): m/z 592 [M - 4Cl]4+, 802 [M -
Com p ou n d 13. A mixture of phthalimide 12 (2.64 g, 3.50
mmol), benzyltriethylammonium chloride (0.80 g, 3.5 mmol),
85% hydrazine hydrate (10 mL), and chloroform (20 mL) was
stirred at room temperature for 24 h and then diluted with
CHCl3 (200 mL). The mixture was washed with 5% aqueous
NaOH solution (2 × 30 mL). After workup, the crude product
was purified by flash chromatography to afford compound 13
1
as a white powder (1.58 g, 71%). Mp: 106-108 °C. H NMR
3Cl]3+, 1221 [M - 2Cl]2+. Anal. Calcd for C152H148Cl4N10O16
‚
(CDCl3): δ 7.26-7.17 (m, 17 H), 6.80 (m, 6 H), 4.11-3.73 (m,
14 H), 2.97 (m, 2 H), 1.98 (m, 2 H). MS (EI): m/z 617 [M]+.
Anal. Calcd for C40H43NO5‚0.5H2O: C, 76.71; H, 7.08; N, 2.23.
Found: C, 76.48; H, 7.05; N, 2.27.
4H2O: C, 70.63; H, 6.08; N, 5.42. Found: C, 70.63; H, 6.53; N,
4.99.
[2]Rota xa n e 22a ‚4Cl was prepared in 37% yield as a red
solid from the reaction of compounds 15‚2PF6 and 16 in the
presence of 14a by using a similar procedure as described
Com p ou n d s 14a and 14b were prepared as white solids
from the reactions of amine 13 with malonic acid or succinic
acid, respectively, according to the method described above for
preparing compound 10. Da ta for 14a . Yield: 92%. Mp: 84-
85 °C. 1H NMR (CDCl3): δ 7.26-7.14 (m, 30 H), 7.10-7.07
(m, 4 H), 6.84-6.76 (m, 12 H), 4.11-4.04 (m, 8 H), 3.94-3.89
(m, 4 H), 3.86-3.78 (m, 8 H), 3.73 (m, 8 H), 3.45 (s, 4 H), 3.17
(s, 1 H), 2.22 (s, 1 H), 1.94 (s, 4 H). MS (ESI): m/z 1303 (M+).
Anal. Calcd for C83H86N2O12‚H2O: C, 75.43; H, 6.71; N, 2.12.
Found: C, 75.56; H, 6.70; N, 2.13. 1Da ta for 4b. Yield: 89%.
Mp: 112-113 °C. 1H NMR (CDCl3): δ 7.26-7.17 (m, 30 H),
7.10-7.07 (m, 4 H), 6.84-6.76 (m, 12 H), 4.11-4.04 (m, 8 H),
3.95-3.91 (m, 4 H), 3.86-3.80 (m, 8 H), 3.74 (m, 8 H), 3.41
(m, 4 H), 2.51 (s, 4 H), 1.94 (s, 4 H). MS (ESI): m/z 1339 [M +
Na]+. Anal. Calcd for C84H88N2O12‚H2O: C, 75.54; H, 6.79; N,
2.10. Found: C, 75.77; H, 6.68; N, 2.07.
1
above for preparing 17‚4Cl. Mp: 168-170 °C. H NMR (CD3-
OD): δ 9.24 (s, 8 H), 8.23 (s, 8 H), 7.23-6.92 (m, 34 H), 6.42-
6.77 (m, 8 H), 4.90-5.85 (m, 8 H), 3.30-4.09 (m, 34 H), 2.12
(s, 2 H), 1.79 (s, 2 H), 1.27 (s, 4 H), 0.89 (s, 2 H). MS (ESI):
m/z 456 [M - 4Cl]4+, 619 [M - 3Cl]3+, 947 [M - 2Cl]2+. Anal.
Calcd for C119H118Cl4N6O12‚2H2O: C, 71.39; H, 6.14; N, 4.20.
Found: C, 71.16; H, 6.23; N, 4.13.
[2]Rota xa n e 22b‚4Cl was prepared in 33% yield as a red
solid from the reaction of compounds 15‚2PF6 and 16 in the
presence of 14b by using a similar procedure as described
1
above for preparing 17‚4Cl. Mp: 202-207 °C (dec). H NMR
(CD3OD): δ 9.25 (s, 8 H), 8.23 (s, 8 H), 7.20-6.92 (m, 34 H),
6.43-6.78 (m, 8 H), 5.81 (m, 8 H), 3.21-4.09 (m, 36 H), 2.63
(s, 4 H), 2.09 (s, 2 H), 1.79 (s, 2 H), 1.27 (s, 2 H). MS (ESI):
m/z 955 [M - 2Cl]2+. Anal. Calcd for C120H120Cl4N6O12‚2H2O:
C, 71.49; H, 6.20; N, 4.17. Found: C, 71.14; H, 6.27; N, 4.14.
[2]Rota xa n e 17‚4Cl. Compound 10 (0.70 g, 0.50 mmol),
9
dicationic compound 15‚2PF6 (0.12 g, 0.17 mmol), dibromide
16 (0.044 g, 0.17 mmol), and KI (20 mg) were added to DMF
(30 mL). The suspension was stirred at ambient temperature
for 10 days. After the solvent was removed under reduced
pressure, and the residue was washed with ether and then
subjected to column chromatography. CHCl3/EtOH (10:1) was
first used as eluent to elute the neutral compounds, and then
MeOH/MeNO2/NH4Cl (2 N aqueous solution) (7:1:2) was used
as eluent. The orange fractions were collected and combined.
The solvent was removed under reduced pressure. The residue
was washed with cold water completely to give [2]rotaxane
17‚4Cl (0.34 g, 34%) as a orange solid, which was purified
[2]Rota xa n es 23a a n d 23b were prepared as white solids
in 26% and 28% yields, respectively, from the reaction of 18
with 19 in the presence of 14a or 14b by using a similar
procedure as described for preparing [2]rotaxane 20. Da ta for
1
23a . Mp: 103-105 °C. H NMR (CDCl3): δ 8.41 (s, 2 H), 8.24
(d, 4 H, J ) 6.7), 7.65 (m, 6 H), 7.17-7.63 (m, 42 H), 6.75-
6.88 (m, 12 H), 4.60 (s, 8 H), 4.07-4.16 (s, 8 H), 3.76-3.92 (s,
20 H), 3.31 (s, 4 H), 2.33 (s, 2 H), 1.90 (s, 4 H). MS (ESI): m/z
1837 [M]+. Anal. Calcd for C115H114N6O16‚H2O: C, 74.49; H,
6.31; N, 4.53. Found: C, 74.29; H, 6.32; N, 4.39. Da ta for 23b.
1
Mp: 144-146 °C. H NMR (CDCl3): δ 8.36 (s, 2 H), 8.16 (d, 4
H, J ) 7.2), 7.65 (br, 4 H), 7.56 (t, 2 H), 7.06-7.28 (m, 42 H),
6.66-6.76 (m, 12 H), 4.49 (s, 8H), 3.68-4.14 (s, 28H), 3.29 (s,
(19) Amundsen, S. Org. Synth. 1944, 24, 46.
J . Org. Chem, Vol. 68, No. 7, 2003 2711

Chen et al.
4H), 1.90 (s, 4H), 1.35 (s, 4H). MS (ESI): m/z 1850 [M]+. Anal.
Calcd for C116H116N6O16‚H2O: C, 75.30; H, 6.32; N, 4.54.
Found: C, 75.07; H, 6.42; N, 4.46.
8.00 (s, 8 H), 7.66 (m, 2 H), 6.65-7.33 (m, 50 H), 5.93 (s, 8 H),
4.93-4.96 (m, 4 H), 4.23-4.26 (m, 4 H), 3.30-4.03 (m, 28 H),
2.89-2.99 (m, 4 H), 2.73 (s, 2 H), 2.18 (s, 4 H), 1.89 (s, 2 H),
[3]Rota xa n es 24a ‚4Cl a n d 24b‚4Cl were prepared as red
solids in 41% and 40% yields, respectively, from the reactions
of 15‚2PF6 with 16 in the presence of [2]rotaxanes 23a or 23b
by using a similar procedure as described for preparing 17‚
4Cl. Da ta for 24a ‚4Cl. Mp: 213-217 °C (dec). 1H NMR
(DMSO-d6): δ 9.89 (s, 4 H), 9.85 (s, 4 H), 9.55 (s, 4 H), 8.80 (s,
4 H), 8.63 (s, 4 H), 8.21 (s, 2 H), 8.50 (m, 4 H), 8.00 (s, 8 H),
7.66 (m, 2 H), 6.65-7.32 (m, 50 H), 5.93 (s, 8 H), 4.93-4.96
(m, 4 H), 4.23-4.26 (m, 4 H), 3.31-4.02 (m, 28 H), 2.89-2.99
(m, 4 H), 2.67 (s, 2 H), 2.12 (s, 4 H), 1.82 (s, 2 H), 1.23 (s, 4 H).
MS (ESI): m/z 797 [M - 3Cl]3+, 1214 [M - 2Cl]2+. Anal. Calcd
1.53 (s, 4 H). MS (ESI): m/z 593 [M - 4Cl]4+, 802 [M - 3Cl]3+
,
1221 [M - 2Cl]2+. Anal. Calcd for C152H148Cl4N10O16‚2H2O: C,
71.62; H, 6.02; N, 5.50. Found: C, 71.24; H, 5.83; N, 5.27.
Ack n ow led gm en t. This work was financially sup-
ported by the NSFC and the Ministry of Science and
Technology of China. We thank Professors J i-Liang Shi
and Min Shi for beneficial discussions.
Su p p or tin g In for m a tion Ava ila ble: Temperature de-
pendent 1H NMR spectra of compounds 17‚4Cl, 21‚4Cl, 22a ‚
4Cl, 22b‚4Cl, 24a ‚4Cl, and 24b‚4Cl. This material is available
free of charge via the Internet at http://pubs.acs.org.
for
C151H146Cl4N10O16‚4H2O: C, 70.55; H, 6.04; N, 5.45.
Found: C, 70.78; H, 6.12; N, 5.57. 24b‚4Cl. Mp: 226-229 °C
1
(dec). H NMR (DMSO-d6): δ 9.86 (s, 4 H), 9.84 (s, 4 H), 9.53
(s, 4 H), 8.80 (s, 4 H), 8.62 (s, 4 H), 8.22 (s, 2 H), 8.50 (m, 4 H),
J O026370I
2712 J . Org. Chem., Vol. 68, No. 7, 2003