Structure of supramolecular complex of flexible molecular tweezers and planar guest in solution

Article abstract of DOI:10.1016/S0040-4020(01)00848-1

Flexible molecular receptors having three aromatic chromophores can bind electron deficient planar guests both in the crystalline state and in solution. The crystalline complex has a triple-decker type donor-acceptor-donor sandwich arrangement in which the guest located between the two terminal aromatic chromophores of the host. Two orientations of the guest, parallel and cross, with respect to the phenanthrene ring of the host were predicted by a molecular mechanics calculation. The former structure was found in the crystalline state. Although the latter was predicted to be less stable, the observed complexation induced shift of the guest supports this orientation in solution. When the terminal naphthalene ring of the host was changed to a benzene ring, the stoichiometry of the crystalline complex changed either to 1:2 or 2:1 depending on the guest.

Full text of DOI:10.1016/S0040-4020(01)00848-1

TETRAHEDRON
Pergamon
Tetrahedron 57 <2001) 8667±8674
Structure of supramolecular complex of ¯exible molecular
tweezers and planar guest in solution
Hirotaka Kurebayashi,a Takeharu Haino,a Shuji Usuib and Yoshimasa Fukazawaa,p
aDepartment of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama Higashi, Hiroshima 739-0046, Japan
bDepartment of Clinical Radiology, Faculty of Health Sciences, Hiroshima International University, 555-36 Gakuendai, Kurose,
Hiroshima 724-0695, Japan
Received 16 July 2001; accepted 20 August 2001
AbstractÐFlexible molecular receptors having three aromatic chromophores can bind electron de®cient planar guests both in the crystalline
state and in solution. The crystalline complex has a triple-decker type donor±acceptor±donor sandwich arrangement in which the guest
located between the two terminal aromatic chromophores of the host. Two orientations of the guest, parallel and cross, with respect to the
phenanthrene ring of the host were predicted by a molecular mechanics calculation. The former structure was found in the crystalline state.
Although the latter was predicted to be less stable, the observed complexation induced shift of the guest supports this orientation in solution.
When the terminal naphthalene ring of the host was changed to a benzene ring, the stoichiometry of the crystalline complex changed either to
1:2 or 2:1 depending on the guest. q 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction
ment of the two aromatic rings as was found in Kagan's
ether9 is
a good building block for constructing
receptors10 that bind aromatic guests with both face-to-
face and face-to-edge interactions.11 Thus, the compound
26 having two units of the dioxa[2.2]orthocyclophane within
the molecule should be a good candidate for the molecular
tweezers because the distance between two terminal
Host±guest chemistry constitutes an important and rapidly
growing research area.1 Many structurally interesting hosts
have been synthesized for studying the nature of the binding
interactions between hosts and guests. Molecular tweezers,2
containing two aromatic chromophores connected by a
spacer are interesting host since they can bind a guest by
squeezing with their arms. On designing molecular tweezers
for uncharged planar p-guests, it is believed that pre-
organization and rigidity are important requisites since
p-stacking interactions3 in an organic solvent are generally
weak. The strong binding of the planar guests was reported
in the rigid molecular tweezers,4 and in some ¯exible
systems.5
Ê
aromatic rings is ideal <ca. 7 A) for p±p stacking with a
guest when it has a syn conformation.12 However, 2 did
not work as molecular tweezers for various electron
acceptors in solution and 2 itself has rod-like double
screw forms in the crystalline state. The cavity size of 2,
if it took the tweezers type syn conformation of the two
terminal benzenes in solution should be too small to bind
any guests. To expand the cavity size we synthesized
compound 3 in which one of the two terminal benzenes of
2 was replaced by the phenanthrene ring. Compound 4
having both the naphthalene and phenanthrene rings was
also prepared.
We have reported that a ¯exible molecular tweezers type
host can be constructed with the dioxa[2.2]orthocyclo-
phanes 1, <5,8-dihydro-1,4-dibenzo[b,f]dioxocine)6,7 as a
basic skeleton. This was known to have three important
conformers <twist-boat, screw, and chair) which are inter-
converting to each other quite rapidly in solution. In the
crystalline state, a derivative of 1 takes the twist-boat
conformation in which the two aromatic rings have a nearly
perpendicular arrangement.8 The perpendicular arrange-
Recently it was found that 4 can bind p-electron de®cient
guests such as tetracyanoquinodimethane 5 <TCNQ), pyro-
mellitic dianhydride 6 <PDA), tetracyanobenzene 7 <TCNB)
effectively to form a 1:1 complex both in solution and in the
crystalline state.13 It was also found that if one of the two
binding chromophores was as small as a benzene ring as in
3, a 1:1 complex formation was not observed in the crystal-
line state, hence, the cavity size of the tweezers plays an
important role in effective binding of the guest. In this paper
we reported the detailed mechanism of guest binding for
these hosts.
Keywords: molecular tweezer; host±guest chemistry; molecular
mechanics; X-ray analysis; chemical shift simulation.
Corresponding author. Tel.: 181-824-24-7427; fax: 181-824-24-0724;
e-mail: fukazawa@sci.hiroshima-u.ac.jp
p
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020<01)00848-1

8668
H. Kurebayashi et al. / Tetrahedron 57 02001) 8667±8674
Scheme 1. a) 1,2,4,5-tetrakis<bromomethyl)benzene, Cs2CO3, acetone, for 12: Arˆbenzene, 32% for 13: Arˆnaphthalene 28%. b) 9,10-dihydroxyphenan-
threne, Cs2CO3, acetone, for 3: Arˆbenzene, 53% for 4: Arˆnaphthalene 37%.
2. Result and discussion
phores lie parallel with each other. The distances between
the least-squares plane of the two aromatic arms of 4´5 is
Ê
6.54 A. The guest is suitably positioned with stacking inter-
2.1. Synthesis
actions to the terminal chromophores and an edge-to-face
interaction to the central durene bridge. The distances
between the least-squares plane of the two aromatic arms
The receptors <3,4) were synthesized by the successive
coupling of 1,2,4,5-tetrakis<bromomethyl)benzene with
the corresponding aromatic diols and with 9,10-dihydroxy-
phenanthrene using Cs2CO3 in acetone <Scheme 1).
Ê
and the guest of 4´5 are 3.31 A <from naphthalene) and
Ê
3.24 A <from phenanthrene), respectively. Two hydrogens
of 5 are pointing to the central durene ring at distances of
Ê
2.74 and 2.70 A, suggesting a favorable distance for the
2.2. X-Ray study of the host±guest complexes
attractive interaction between the hydrogen of the guest
and the durene ring of 4.
X-Ray crystallographic analyses were carried out in order to
know the precise structures of these complexes. As
expected, the host clearly has a tweezers type conformation
with face-to-face syn arrangement of the two terminal
aromatic rings in 4´5 <Fig. 1). The two terminal chromo-
Quite similar stacking mode between 4 and 6 was observed
in the crystal of complex 4´6. It has almost the same face-to-
Ê
face interactions <interplanar distances of 3.32, 3.33 A
between phenenthrene, naphtharene and guest, respectively)
and edge-to-face interaction <a hydrogen of the guest point-
ing at nearly centroid of the durene unit at a distance of
Ê
2.78 A).
In spite of the close similarity of the structures in 4´5 and
4´6, relative arrangement of the two terminal aromatic rings
in these complexes is quite different. As can be seen in Fig.
2, the two terminal arenes of the complex 4´6 are rotated
with each other in opposite direction around the axis
connecting the two centroids of the two oxygen carrying
six-membered rings. In accord with this rotation, the central
durene also rotates to have inclination of the line connecting
Figure 1. Ortep drawing of <a) 4´5 and <b) 4´6.

H. Kurebayashi et al. / Tetrahedron 57 02001) 8667±8674
8669
Figure 4. Ortep drawing of 3´62.
both by the face-to-face and face-to-edge interactions to
form 1:2 crystalline complex.
The crystallographic study of the host±guest complexes has
disclosed that at least one perpendicular arrangement of the
neighboring chromophores should be a prerequisite for the
ef®cient binding of the planar guest. Both the charge transfer
type p±p stacking interaction between the terminal
aromatic chromophore<s) and a guest and CH-p type face-
to-edge interactions14 should be the main contributor for the
ef®cient guest binding.
Figure 2. Front <a,c) and top <b,d) views of 4´5 <a,b) and 4´6 <c,d).
the two unsubustituted carbons of the durene ring with
respect to the least-squares plane of the phenanthrene ring
by ca. 128 <Fig. 2c). On the other hand, the two terminal
aromatic rings of 4´5 do not rotate and the two oxygen
carrying six-membered rings of the arenes are superimposed
when viewed along the perpendicular direction of one of the
two terminal arenes <Fig. 2b). Accordingly, no rotation of
the central durene moiety was observed.
2.3. Binding behavior in solution
Simple aromatics such as benzene and naphthalene showed
no propensity for binding, while p electron de®cient
systems such as 5±7 were complexed in solution, hence
electron donor±acceptor interaction plays an important
role in the binding. New broad charge transfer bands15
were observed <for 4; 520 <5), 520 <6), 460 <7) nm, respec-
tively) in CHCl3. A 1:1 stoichiometry of the complex was
determined by a continuous variation method using the
CT-band in all cases.
The binding behavior of the host is quite different if one of
the two binding chromophores was as small as benzene ring.
Unexpectedly, the 1:1 complex formation was not observed
in the crystalline state and the conformer of the host is
different from the tweezers form. It gave 2:1 complex, and
the conformation of host 3 in the crystalline complex 32´5 is
`L' character type conformation, <Fig. 3) in which the
phenanthrene and central durene are perpendicular with
each other. In the complex, the two phenanthrene chromo-
phores fold the guest with the triple-decker sandwich type
arrangement, in which the two hosts grasp the guest both by
face-to-face and face-to-edge interactions. While the two
arenes <phenenthrene and durene) of 3 contribute signi®-
cantly for holding the guest, the terminal benzene does not.
The stoichiometry of the complex was further supported by
1H NMR measurement in CHCl3. By titrating a solution of
guest with that of a host using the complexation induced
shift <CIS) of the guest, a standard hyperbolic curve could
be constructed. The association constants were determined
by the direct ®tting using a nonlinear least squares pro-
cedure with damping Gauss±Newton algorithm.16 They
are shown in Table 1 together with those of the reference
The same host holds guest 6 in 1:2 fashion in the crystalline
state <Fig. 4). In this complex, host 3 takes `Z' character
form in which three aromatic chromophores form two
perpendicular corners. Each corner can hold the guest
Table 1. Association constants in CDCl3 at 268C
3
4
8
9
10
11
5
6
7
35<3)
60<7)
73<2)
130<2)
1000<100)
1000<110)
190<70)
95<13)
41<11)
56<4)
34<2)
27<4)
±
±
46<11)
12<3)
1.4<5)
10<1)
Table 2. Complexation induced shift of fully bound guest <ppm)
3
4
8
9
10
11
5
6
7
1.34<6)
1.10<4)
1.07<1)
1.64<2)
1.30<3)
1.35<6)
0.28<1)
0.43<1)
0.46<1)
0.24<6)
0.36<1)
0.70<6)
±
±
0.10<3)
0.33<1)
0.46<1)
0.27<1)
Figure 3. Ortep drawing of 32´5.

8670
H. Kurebayashi et al. / Tetrahedron 57 02001) 8667±8674
hosts. The same ®tting procedure also gave the CIS value of
the fully bound guest <Table 2).
The association constants of 4 are all larger than that for 3,
re¯ecting the better donor±acceptor interaction between the
host and guest, because the former has larger terminal
aromatic chromophore than 3 has. The association constants
of host 3 with 6 and 7 are almost identical to those of
reference host 8. The host of 32´5 in the crystalline state
has L character form and the terminal benzene ring does
not contribute in the guest binding. Hence, the similarity
of the association constants suggested that the terminal
benzene ring of 3 does not contribute for the guest binding
also in solution. However, the structure of these complexes
in solution should be quite different with each other, because
the CIS values of 3´6 and 3´7 are far larger than that of 8´6
and 8´7, respectively. Since the binding constants of
reference host 9 toward 6 and 7 are not so different from
that of host 8, it suggested that the 9,10-dioxyphenenthrene
ring itself is the main contributor for the guest binding in
host 3. The binding constants of reference host 10 toward 6
and 7 are also not so different to that of host 9. It is
interesting that the product of the two binding constants
<ka9´6 ´ ka10´6) is close to that of host 4. This might be an
evidence for the cooperative contribution of both of the
terminal aromatic chromophores, phenanthrene and
naphthalene, for the guest binding of 4 in solution. The
same is true for the binding of 7, though the product of
the two binding constants is one third of that for 4.
It is known that the association constant of ¯exible
molecular tweezers and an electron de®cient guest is solvent
dependent. In order to know the solvent effect for the host±
1
Figure 5. Calculated structures of 4´6.
guest complexation, H NMR titration was carried out in
3 nor 4 showed any
acetone-d6, however, neither
propensity for binding any guests. This result showed that
the polarity of the solvent has a very important role in the
guest binding.
difference is the orientation of the guest. The guest of c3 was
rotated 908 from c1. Since the cleft of the host is not so deep
that the guest is not fully buried in this cleft and almost one
third of it is exposed outside. In this orientation the contact
area between the host and guest is smaller than that of the
parallel orientation and hence, it is less stable than the fully
buried one. Again the eclipsed arrangement of the two
terminal chromophores in c4 <7.4 kcal mol21 from c1) is
less stable than c3, but the structural characteristics are
very similar. The two terminal chromophores of c5
<8.0 kcal mol21 from c1) are not parallel to each other and
phenanthrene unit bent outward. In this structure, the guest
stacks on the phenanthrene unit with the perpendicular
arrangement, as was found in c3 and c4. The guest rotated
908 in c6 <9.0 kcal mol21 from c1) structure.
2.4. Modeling study of complex 4´6
In order to know the structure of the complex in solution, the
modeling study of 4´6 was carried out with AMBERp force
®eld using GB/SA chloroform solvation model17 in the
program package of Macromodel V6.5.18 Since the low
mode search algorithm19 is known to be ef®cient to generate
all the possible structures of a host±guest complex we
applied the method to obtain the most probable structures
of the complex. The 5000 initial structures of the complex
were generated and then optimized. The structures thus
obtained are shown in Fig. 5.
It is noteworthy that the relative stability of these structures
mainly comes from the difference of the van der Waals
interaction and Coulomb interaction of the partial charge
of the individual atom in the binding partners. Charge
transfer type interaction between the electron donor and
acceptor should be operative in the actual case, however,
such type of interaction cannot be included in the force ®eld
calculations. Hence, the relative stability of the structures
predicted in this calculation not always corresponds to the
actual stability in solution.
The most stable structure <c1) predicted by this calculation
is almost identical to that found in the crystalline state. The
two terminal arenes of the host rotated with each other
around the axis connecting the two controids of the two
oxygen carrying six-membered rings. The long axis of the
guest is parallel to that of phenanthrene ring. The second
stable structure <c2) has eclipsed orientation of the two
terminal chromophores of the host as is found in the crystal-
line structure of 4´5. The energy difference of the two is
2.7 kcal mol21. Following to these two is the structure <c3,
5.6 kcal mol21 from c1) similar to the most stable one. The
Using these structures, the theoretical CIS of the guest was

H. Kurebayashi et al. / Tetrahedron 57 02001) 8667±8674
8671
estimated. The CIS value of the individual structures was
calculated with magnetic anisotropy due to the ring current
effect of the three aromatic rings. The calculated up-®eld
shifts of these structures are 3.58, 3.75, 1.65, 1.71, and
1.36 ppm for c1, c2, c3, c4, and c5, respectively.
of the molecule is left shielded from the binding arms of
the host. The exposed part is the one of the two polar
moieties <acid anhydride moiety) of the guest and the
solvent molecules can interact to this moiety.21 This
solvation of the guest should be stabilizing interaction. In
other words, both c3 and c4 have extra solvation energy of
the entrapped guest when compared to the cases of the fully
buried guest <c1 and c2). Thus, it is not unreasonable to
assume that the latter two are more stable than the former
structures due to the extra solvation of the guest. It is rather
dif®cult to verify the reversal of the relative stability of these
structures in solution. However, the close similarity to the
observed CIS value <1.30 ppm) to that of the calculated one
<1.65 and 1.71 ppm for c3 and c4, respectively) is a good
experimental proof to the reversal of the relative stability of
the calculated structures.
2.5. Structure of the complexes in solution
The essential aspect of molecular recognition is to under-
stand nature of the interaction of molecules. Presumably,
there should be a speci®c arrangement of the two molecules
at which the energy is lower than any other orientations.
Hence, it is very important to elucidate the precise structures
of a host±guest complex in solution to understand the nature
of the interaction between the binding partners. However,
the structure elucidation of the host±guest complex is rather
elusive because the structure found in the crystalline state
does not always correspond to that in solution. Solvent
molecules play an important role in controlling the relative
arrangement of the interacting pair. We have found that
NMR chemical shift simulation method20 is very ef®cient
and reliable to know the relative population of dynamically
equilibrating conformational change of a ¯exible macro-
cyclic compound.
The reversal of the stability for the perpendicular guest <c3
and c4) with respect to the parallel <c1 and c2) in chloroform
solution is thus explained by the difference of the extent of
solvation on the buried guest in the host cavity. The fact that
both 3 and 4 did not show any propensity to form supra-
molecular complex with any of these acceptor in acetone is
the further experimental proof that the solvation/desolvation
play a very important role not only in the binding strength
but also the relative arrangement between the host and
guest.
From the binding study it was ascertained that the three
aromatic chromophores in the hosts worked cooperatively,
since the binding constant of 4 toward 6 is nearly equal to
the product of that for 9 and 10. Moreover, the modeling
study suggested that the tweezers form of the host is the
most favorable for binding a guest. Actually, the molecular
mechanics calculations predicted that the most stable
structure of the complex is c1 and the second one is c2.
Although they differ in the relative arrangement of the
two terminal chromophores <skewed and eclipse), they are
essentially identical with respect to the orientation of the
guest. Actually, the calculated CIS values of the guest
are quite similar <3.58 ppm for c1, 3.75 ppm for c2).
Re¯ecting the perpendicular arrangement of the guest,
the calculated CIS values of c3 and c4 are small
<1.65 ppm for c3 and 1.71 ppm for c4) when compared to
the former cases.
3. Conclusion
Flexible molecular receptors <3,4) having three aromatic
chromophores can bind electron de®cient p-system such
as 5 or 6 both in the crystalline state and in solution. The
crystallographic analysis disclosed that both complexes 4´5
and 4´6 have a triple-decker type donor±acceptor±donor
sandwich arrangement in which the guest located between
the two terminal aromatic chromophores of the host. When
the terminal aromatics naphthalene ring of 4 was changed to
a benzene ring, the stoichiometry of the crystalline host±
gust complex changed either to 1:2 or 2:1 depending on the
guest. In the 1:2 complex <3´62) the host has Z character
conformation. The host of its form has two perpendicular
corners and each corner can hold the guest to form 1:2
complex in the crystalline state. On the other hand, in the
2:1 complex <32´5), the host has L character conformation.
Combination of the two L character hosts makes the box
type cavity in which the guest was encapsulated with both
face-to-face and face-to-edge interactions. Two orientations
of the guest, parallel and cross, with respect to the
phenanthrene ring of the host were predicted in the triple-
decker complex 4´6 by a molecular mechanics calculation.
The former structure was found in the crystalline state and
predicted to be more stable than that of the cross orientation.
Since the depth of the cavity of the receptor is not enough
for the cross arrangement, a part of the guest was not
covered by the two terminal chromophores of the host.
Although the latter was predicted to be less stable, the
observed complexation shift of the guest supports this
orientation in solution. The solvation to the exposed part
of the guest should give extra stabilization of the complex
in solution.
It is well known that the stability of supramolecular
complexes depends on attractive interactions between the
host and guest and on solvation of the binding partners.
Since the host and guest were separately solvated in solu-
tion, the desolvation of the host and guest is requisite in the
association process. The desolvation process should be
energetically up-hill and hence, an association took place
only when the energy gain between the host and guest inter-
action exceeds this unfavorable energy. Thus, the extent of
solvation and desolvation of the binding partners play an
important role in the structure of the supramolecular
complex.
Both in structures c1 and c2, the guest was fully buried in
the cleft of the host, since the molecular size of the guest is
almost identical to that of one of the terminal chromophores
of the host, and hence, the guest was completely shielded
from the solvent molecules. On the other hand, in
structure c3 and c4, the depth of the cleft is not enough
for the perpendicularly arranged guest, and hence, a part

8672
H. Kurebayashi et al. / Tetrahedron 57 02001) 8667±8674
4. Experimental
<%): 496 <10). IR <KBr); C34H24O4 <496.2): calcd C 82.24,
H 4.87. found: C 82.32, H 5.09.
Melting points are uncorrected. 1H NMR spectra were
recorded at 270 and 500 MHz, and 13C NMR spectra were
4.1.3. 5,6,7,8-Tetrahydro-1,4-90,100-phenanthro[b]dioxo-
cin 69). A mixture of phenanthrenequinone <500 mg,
2.40 mmol) and a catalytic amount of palladium±carbon
in 5 ml of THF was stirred under H2 for one day at room
temperature. The reaction mixture was ®ltered under Ar
and the ®ltrate was added dropwise to a mixture of 1,4-
dibromoburane <550 mg, 2.54 mmol) and cesium carbonate
<1.90 g, 5.85 mmol) in 100 ml of acetone at re¯uxed
temperature. The mixture was re¯uxed for 3 h and was
®ltered. The solvent was removed under reduced pressure,
residue was puri®ed by silicagel column chromatography
<CHCl3) and then by GPC <CHCl3) to afford 400 mg <63%
yield) of 9; colorless powder, mp 100±1028C; IR <KBr)
1
recorded at 67.5 and 125 MHz. H and 13C chemical shifts
were measured in ppm relative to internal Me4Si, and
coupling constants are expressed in Hz.
4.1. Titration
NMR titrations were performed at 500 MHz on a JEOL
Lamda500 instrument at ambient temperature <approxi-
mately 268C) by treating 500 mL of guest <1 mM in
CDCl3) with aliquots of host <15 mM in CDCl3) and moni-
toring the changes in the chemical shift. Nonlinear least
squares regression curve ®tting was used to determine the
binding constants, along with the ®nal chemical shift of each
of the monitored protons.
1
1259 cm21; H NMR <270 MHz CDCl3): d 8.62±8.20 <m,
2H), 8.27±8.23 <m, 2H), 7.63±7.56 <m, 4H), 4.60 <bs, 4H),
2.04 <bs, 4H); 13C NMR <67.5 MHz CDCl3): d 139.665,
129.019, 128.005, 126.654, 125.304, 122.427, 122.175,
72.354, 27.453; MS <70 eV, EI): m/z <%): 264 <27) [M1];
HRMS <EI) for C18H16O2: m/z <calcd) M1ˆ264.1150; m/z
<obsd) ˆ264.1146.
4.1.1. 9,13,18,22-Tetraoxa-9,10,12,13,18,19,21,22-octa-
hydrobenzo-90,100-phenanthro[e,e0]benzo[1,2-a:4,5-a0]-
dicyclooctene 63). A mixture of phenanthrenequinone
<280 mg, 1.34 mmol) and a catalytic amount of palla-
dium±carbon in 5 ml of THF was stirred under H2 for one
day at room temperature. The reaction mixture was ®ltered
under Ar and the ®ltrate was added dropwise to a mixture of
12 <470 mg, 1.18 mmol) and cesium carbonate <1.2 g,
3.69 mmol) in 350 ml of acetone at re¯uxed temperature.
The mixture was re¯uxed for 2 h and was ®ltered. The
solvent was removed under reduced pressure, residue was
puri®ed by silicagel column chromatography <CHCl3) and
then by GPC <CHCl3) to afford 280 mg <53% yield) of 3;
colorless powder, mp 216±2178C; IR <KBr): 1280
4.1.4. 5,8-Dihydro-1,4-20,30-naphthobenzo[b]dioxocin 610).
A
mixture of 1,2-bis<bromomethyl)benzene <500 mg,
1.89 mmol), 2,3-dihydroxynaphthalene <300 mg, 1.88
mmol) in 30 ml of acetone was added dropwise to a suspen-
sion of cesium carbonate <1.52 g, 4.68 mmol) in 100 ml of
acetone at re¯uxed temperature. The mixture was re¯uxed
for 1 h and was ®ltered. The solvent was removed under
reduced pressure, residue was puri®ed by silicagel column
chromatography <10% ethylacetate/hexane) to afford
130 mg <26% yield) of 10; colorless powder, mp 178±
1240 cm21; H NMR <270 MHz CDCl3): d 8.59±8.55 <m,
1
1
1798C; IR <KBr) 1260 cm21; H NMR <270 MHz CDCl3):
2H), 8.27±8.23 <m, 2H), 7.64±7.25 <m, 4H), 7.04 <s, 2H),
6.91±6.87 <m, 4H), 5.63 <s, 4H), 5.33 <s, 4H); 13C NMR
<67.5 MHz CDCl3): d 149.587, 140.344, 136.096, 136.066,
129.618, 128.595, 127.983, 126.761, 125.539, 123.706,
122.483, 121.918, 74.892, 674. 47; MS <70 eV, EI): m/z
<%): 446 <8) [M1]; C30H22O4 <446.1): calcd C 80.70, H
4.97. found: C 80.57, H 5.00.
d 7.68±7.65 <m, 2H), 7.44 <s, 2H), 7.34±7.30 <m, 2H),
7.28±7.22 <m, 4H), 5.46 <s, 4H); 13C NMR <67.5 MHz
CDCl3): d 150.175, 135.827, 130.663, 128.921, 128.524,
126.675, 124.780, 118.118, 75.487; MS <70 eV, EI): m/z
<%): 262 <33) [M1]; HRMS <EI) for C18H14O2: m/z <calcd)
M1ˆ262.0994; m/z <obsd) ˆ262.0993.
4.1.5. 5,6,7,8-Tetrahydro-1,4-20,30-naphtho[b]dioxocin 611).
A mixture of 1,4-dibromobutane <130 mg, 0.60 mmol), 2,3-
dihydroxynaphthalene <100 mg, 0.63 mmol) in 30 ml of
acetone was added dropwise to a suspension of cesium car-
bonate <500 mg, 1.53 mmol) in 30 ml of acetone at re¯uxed
temperature. The mixture was re¯uxed for 2 h and was
®ltered. The solvent was removed under reduced pressure,
residue was puri®ed by silicagel column chromatography
<CHCl3) to afford 120 mg <90% yield) of 11; colorless oil;
IR <KBr) 1225 cm21; 1H NMR <270 MHz CDCl3): d 7.68±
7.65 <m, 2H), 7.33±7.30 <m, 2H), 7.16 <s, 2H), 4.19 <bs, 4H),
2.16 <bs, 4H); 13C NMR <67.5 MHz CDCl3): d 150.146,
129.538, 126.273, 124.029, 109.403, 69.248, 26.173; MS
<70 eV, EI): m/z <%): 214 <100) [M1]; HRMS <EI) for
C14H14O2: m/z <calcd) M1ˆ214.0994; m/z <obsd)ˆ
214.0986.
4.1.2. 9,13,20,24-Tetraoxa-9,10,12,13,20,21,23,24-octa-
hydro-30,40-naphtho-90,100-phenanthro[e,e0]benzo[1,2-a:
4,5-a0]dicyclooctene 64). A mixture of phenanthrene-
quinone <110 mg, 0.52 mmol) and a catalytic amount of
palladium±carbon in 5 ml of THF was stirred under H2
for one day at room temperature. The reaction mixture
was ®ltered under Ar and the ®ltrate was added dropwise
to a mixture of 13 <120 mg, 0.28 mmol) and cesium car-
bonate <400 mg, 1.23 mmol) in 150 ml of acetone at
re¯uxed temperature. The mixture was re¯uxed for 3 h
and was ®ltered. The solvent was removed under reduced
pressure, residue was puri®ed by silicagel column chroma-
tography <CHCl3) and then by GPC <CHCl3) to afford 50 mg
<37% yield) of 4; colorless powder, mp 262±2638C; IR
1
<KBr) 1286, 1240 cm21; H NMR <270 MHz CDCl3): d
8.59±8.55 <m, 2H), 8.26±8.23 <m, 2H), 7.69±7.53 <m,
6H), 7.41 <s, 2H), 7.33±7.30 <m, 2H), 7.07 <s, 2H), 5.43
<s, 4H), 5.37 <s, 4H); 13C NMR <67.5 MHz CDCl3): d
149.931, 140.243, 136.148, 130.663, 129.563, 128.585,
128.004, 126.751, 126.675, 125.529, 124.857, 122.488,
121.908, 118.164, 74.891, 74.800; MS <70 eV, EI): m/z
4.1.6. 2,3-Bis6bromomethyl)-6,11-dioxa-5,12-dihydro-
benzo[e]benzo[1,2-e]cyclooctene 612).
A mixture of
1,2,4,5-tetrakis<bromomethyl)benzene <1 g, 2.2 mmol),
catechol <0.24 g, 2.1 mmol) and cesium carbonate <1.8 g,

H. Kurebayashi et al. / Tetrahedron 57 02001) 8667±8674
8673
5.3 mmol) in 500 ml of acetone was stirred for a day and
was ®ltered. The solvent was removed under reduced
pressure, residue was puri®ed by silicagel column chroma-
tography <CHCl3) and then by GPC <CHCl3) to afford 0.29 g
<32% yield) of 12; colorless powder, mp 87±898C; IR
to a maximum 2u of 1108. Of 5135 total unique re¯ections,
4242 were considered observed at the level of uFou .
2:0suFou: The structure was solved by the direct method
<Sir97). All non-hydrogen atoms were located on the initial
E synthesis. Hydrogen atoms were found from the
difference fourier map and included in the further calcula-
tions. Full matrix least squares re®nements with anisotropic
88 non-hydrogen atoms and 54 isotropic hydrogens
converged to a conventional Rˆ0.049, w2Rˆ0.173.
1
<KBr): 1248 cm21; H NMR <270 MHz CDCl3): d 7.19 <s,
2H), 7.04±6.92 <m, 4H), 5.36 <s, 4H), 4.60 <s, 4H); 13C
NMR <67.5 MHz CDCl3): d 149.885, 136.515, 161.557,
126.744, 123.779, 74.139, 29.136; MS <70 eV, EI): m/z
<%): 396 <22) [M221], 398 <43) [M1], 400 <21) [M121].
C16H14O279Br2: calcd 395.9361, found 395.9334,
C16H14O279Br81Br: calcd 397.9341, found 397.9341,
C16H14O281Br2: calcd 399.9323, found 399.9290 <MS).
4.2.3. X-Ray diffraction analysis of 4´6 complex. The
crystal data for 4´6 complex are as follows; Monoclinic,
space group P21/a with aˆ22.801 <3), bˆ14.767 <2),
Ê
Ê 3
cˆ10.859 <1) A, bˆ91.86 <1)8, Vˆ3654.5 <8) A , and
Zˆ4. The empirical formula is <C34H22O4)2<C10H2O6)3,
molecular weight is 1646, and calculated density is
1.49 g cm23. The three-dimensional intensity data were
collected by the use of graphite-monochromated Cu-Ka
4.1.7. 2,3-Bis6bromomethyl)-6,13-dioxa-5,14-dihydro-20,30-
naphtho[e]benzo[1,2-e]cyclooctene 613). A mixture of
1,2,4,5-tetrakis<bromomethyl)benzene
<200 mg,
0.24
mmol), and 2,3-dihydroxynaphthalene <26 mg, 0.16 mmol)
and cesium carbonate <170 mg, 0.52 mmol) in 100 ml of
acetone was stirred for a day and was ®ltered. The solvent
was removed under reduced pressure, residue was puri®ed
by silicagel column chromatography <CHCl3) and then by
GPC <CHCl3) to afford 23 mg <28% yield) of 13; colorless
Ê
radiation <lˆ1.54178 A) on a Rigaku AFC-4 automatic
four-circle diffractometer up to a maximum 2u of 1108 Of
5135 total unique re¯ections, 4242 were considered
observed at the level of uFou . 2:0suFou: The structure was
solved by the direct method <Sir97). All non-hydrogen
atoms were located on the initial E synthesis. Hydrogen
atoms were found from the difference fourier map and
included in the further calculations. Full matrix least squares
re®nements with anisotropic 116 non-hydrogen atoms and
54 isotropic hydrogens converged to a conventional R factor
of 0.0652.
1
powder, mp 188±1898C; IR <KBr): 1247 cm21; H NMR
<270 MHz CDCl3): d 7.70±7.65 <m, 2H), 7.46 <s, 2H),
7.30±7.35 <m, 2H), 7.20 <s, 2H), 5.40 <s, 4H), 4.60 <s,
4H); 13C NMR <67.5 MHz CDCl3): d 150.091, 137.302,
136.591, 131.435, 130.648, 126.744, 125.002, 118.149,
74.853, 29.098; MS <70 eV, EI): m/z <%): 446 <3)
[M221], 448 <7) [M1], 450 <3) [M121]. C20H16O2Br2
<447.9): calcd C 53.60, H 3.60. found: C 53.57, H 3.78.
4.2.4. X-Ray diffraction analysis of 4´5 complex. The
crystal data for 4´5 complex are as follows; Orthorhombic,
space group Pc21/n with aˆ17.212<2), bˆ37.939 <2),
4.2. Crystal structure determinations
Ê
Ê 3
cˆ15.462 <1) A, Vˆ10096<4) A , and Zˆ12. The empirical
formula is <C34H22O4)<C12H4N4), molecular weight is 700,
. The three-
4.2.1. X-Ray diffraction analysis of 3´6 complex. The
crystal data for 3´6 complex are as follows; Monoclinic,
space group P21 with aˆ8.284 <4), bˆ30.644 <5),
and calculated density is 1.38 g cm23
dimensional intensity data were collected by the use of
Ê
Ê
Ê 3
graphite-monochromated Cu-Ka radiation <lˆ1.54178 A)
cˆ7.823 <5) A, bˆ98.859 <5)8, Vˆ1962 <2) A , and Zˆ4.
The empirical formula is <C30H22O4)<C10H2O6)2, molecular
weight is 882, and calculated density is 1.49 g cm23. The
three-dimensional intensity data were collected by the use
of graphite-monochromated Cu-Ka radiation <lˆ
on a Rigaku AFC-4 automatic four-circle diffractometer up
to a maximum 2u of 1108 Of 5339 total unique re¯ections,
3682 were considered observed at the level of uFou .
2:0suFou: The structure was solved by the direct method
<Sir97). All non-hydrogen atoms were located on the initial
E synthesis. Hydrogen atoms were found from the
difference fourier map and included in the further calcula-
tions. Full matrix least squares re®nements with anisotropic
54 non-hydrogen atoms and 28 isotropic hydrogens
converged to a conventional Rˆ0.054, w2Rˆ0.175.
Ê
1.54178 A) on a Rigaku AFC-4 automatic four-circle
diffractometer up to a maximum 2u of 1108. Of 2089 total
unique re¯ections, 1580 were considered observed at the
level of uFou . 2:0suFou: The structure was solved by the
direct method <Sir97).22 All non-hydrogen atoms were
located on the initial E synthesis. Hydrogen atoms were
found from the difference fourier map and included in the
further calculations. Full matrix least squares re®nements
with anisotropic 66 non-hydrogen atoms and 26 isotropic
hydrogens converged to a conventional R factor of 0.032.
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Ê
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