A cyclic oligophenylene containing two 1,8-naphthalene units bridged by two face-to-face biphenyl linkages exhibiting unusual strain and π-π interaction

Article abstract of DOI:10.1021/ol0001012

equation presented Strong π-π interaction 1,8-[1,8-Naphthalenediylbis(4′,4-biphenyldiyl)]naphthalene, a very stable strained cyclophane, has been synthesized in moderate yield using the copper-catalyzed coupling of 1,8-bis(4-(tributylstannyl)phenyl)naphth

Full text of DOI:10.1021/ol0001012

ORGANIC
LETTERS
2000
Vol. 2, No. 14
2081-2083
A Cyclic Oligophenylene Containing
Two 1,8-Naphthalene Units Bridged by
Two Face-to-Face Biphenyl Linkages
Exhibiting Unusual Strain and π−π
Interaction
Masahiko Iyoda,* Terumasa Kondo, Kazumi Nakao, Kenji Hara,
Yoshiyuki Kuwatani, Masato Yoshida, and Haruo Matsuyama
Department of Chemistry, Graduate School of Science, Tokyo Metropolitan UniVersity,
Hachioji, Tokyo 192-0397, Japan
iyoda-masahiko@c.metro-u.ac.jp
Received April 20, 2000
ABSTRACT
1,8-[1,8-Naphthalenediylbis(4′,4-biphenyldiyl)]naphthalene, a very stable strained cyclophane, has been synthesized in moderate yield using
the copper-catalyzed coupling of 1,8-bis(4-(tributylstannyl)phenyl)naphthalene. The X-ray analysis of the titled compound discloses bent p,p′-
biphenylylene chains with splayed naphthalene rings, and the p,p′-biphenylylene chains located face-to-face indicate a fairly strong π−π
interaction.
Cyclophanes and cyclic oligophenylenes have attracted
considerable interest among experimental and theoretical
chemists,1,2 because of their unique structures, π-π interac-
tion, molecular strain, and aromaticity, and as substrates for
host-guest chemistry. Although 2,17-dithia[3,3](4,4′)-
biphenylophane 1b has been synthesized (Figure 1),3a the
(1) For general reviews of cyclophanes, see Weber, E., Ed. Cyclophanes.
In Topics in Current Chemistry; 1994; Vol. 172. Vo¨gtle, F. Cyclophane
Chemistry; Wiley: New York, 1993. Diederich, F. Cyclophanes; Mono-
graphs in Supramolecular Chemistry; The Royal Society of Chemistry:
London, 1991.
(2) For oligophenylenes, see, Staab, H. A.; Binnig, F. Chem. Ber. 1967,
100, 293. Irngartinger, H.; Leiserowitz, L.; Schmidt, G. M. J. Chem. Ber.
1970, 103, 1132. Wittig, G.; Ru¨mpler, K.-D. Liebigs Ann. 1971, 751, 1.
Fujioka, Y. Bull. Chem. Soc. Jpn. 1984, 57, 3494. Cram, D. J.; Kaneda, T.;
Helgeson, R. C.; Brown, S. B.; Knobler, C. B.; Maverick, E.; Trueblood,
K. N. J. Am. Chem. Soc. 1985, 107, 3645. Chan, C. W.; Wong, H. N. C.
J. Am. Chem. Soc. 1985, 107, 4790; 1988, 110, 462. Ko¨nig, B.; Heinze, J.;
Meerholz, K.; de Meijere, A. Angew. Chem., Int. Ed. Engl. 1991, 30, 1361.
Percec, V.; Okita, S. J. Polym. Sci. Polym. Chem. Ed. 1993, 31, 877. Wong,
T.; Yuen, M. S. M.; Mak, T. C. W.; Wong, H. N. C. J. Org. Chem. 1993,
58, 3118. Rajca, A.; Safronov, A.; Rajca, S.; Shoemaker, R. Angew. Chem.,
Int. Ed. Engl. 1997, 36, 488. Hensel, V.; Lu¨tzow, K.; Jacob, J.; Gessler,
K.; Saenger, W.; Schlu¨ter, A.-D. Angew. Chem., Int. Ed. Engl. 1997, 36,
2654. Kelly, T. R.; Lee, Y.-J.; Mears, R. J. J. Org. Chem. 1997, 62, 2774.
Hensel, V.; Schlu¨ter, A. D. Chem. Eur. J. 1999, 5, 421.
Figure 1. 3,3-Biphenylophanes.
π-π interaction between two biphenyl rings seems to be
not very large due to release of strain energy by bending
10.1021/ol0001012 CCC: $19.00 © 2000 American Chemical Society
Published on Web 06/09/2000

the 2-thiapropano bridges. In contrast, cyclic oligophenylene
2 with a [3.3]biphenylophane framework like 1a can be
expected to have a conformationally rigid structure with a
face-to-face arranged 1,8-diphenylnaphthalene system which
has been investigated extensively over the last several
decades.4 We now report here the first synthesis of the cyclic
oligophenylene 2 using the copper-catalyzed coupling of 1,8-
bis(4-(tributylstannyl)phenyl)naphthalene.
of 7 with transition metal catalysts were unsuccessful, the
coupling reaction of 1,8-bis(4-(tributylstannyl)phenyl)naph-
thalene 8 with Cu(NO3)2‚3H2O (2.2 equiv) in THF resulted
in the formation of 2 in moderate yield. Thus, the reaction
of 7 with butyllithium (3.2 equiv), followed by treatment
with chlorotributyltin(IV) (3.5 equiv) gave 8 in 76% yield.
The reaction of 8 with Cu(NO3)2‚3H2O (2.2 equiv) in THF
at room temperature for 1 h produced 2 in 41% yield,
together with 9 (9%) and 10 (5%). To clarify the properties
of the face-to-face arranged biphenyl units in 2, the open
chain analogue 126 was synthesized in 50% yield by the
palladium-catalyzed cross-coupling reaction of 5 with 11.
Recrystallization of 2 from chlorobenzene gave single
crystals, and the crystal structure of 2 was determined by
X-ray diffraction method.7 As shown in Figure 2, the two
Compound 2 was synthesized according to the reaction
sequence outlined in Scheme 1. The arylzinc reagent 4 was
Scheme 1. Syntheses of 2 and Related Compounds
Figure 2. The molecular structure of 2.
p,p′-biphenylylene chains are located face-to-face. The
intramolecular distances between two phenyl carbons are
2.99-3.66 Å (C11-C42, 3.03 Å; C20-C33, 2.99 Å; C14-
prepared from 3 in THF by successive treatment with
butyllithium (1.2 equiv) and zinc chloride (1.3 equiv). The
reaction of 1,8-diiodonaphthalene 5 with 4 (4 equiv) in the
presence of Pd(PPh3)4 (10 mol %) in THF at room temper-
ature for 15 h proceeded smoothly to give 65 in 60% yield.
Treatment of 6 with ICl (2.0 equiv) in CCl4 at -20 to +50
°C produced 7 in 74% yield. Although attempted couplings
(3) For biphenylophanes, see (a) Staab, H. A.; Haenel, M. Chem. Ber.
1973, 106, 2190. (b) Thulin, B.; Wennerstro¨m, O.; Somfai, I.; Chmielarz,
B. Acta Chem. Scand. 1977, B31, 135. (c) Nishimura, J.; Doi, H.; Ueda,
E.; Ohbayashi, A.; Oku, A. J. Am. Chem. Soc. 1987, 109, 5293. (d) Tani,
K.; Seo, H.; Maeda, M.; Imagawa, K.; Nishiwaki, N.; Ariga, M.; Tohda,
Y.; Higuchi, H.; Kuma, H. Tetrahedron Lett. 1995, 36, 1883. (e) van Eis,
M. J.; de Kanter, F. J. J.; de Wolf, W. H.; Bickelhaupt, F. J. Am. Chem.
Soc. 1998, 120, 3371.
2082
Org. Lett., Vol. 2, No. 14, 2000

C39, 3.66 Å; C17-C36, 3.65 Å). Thus, the benzene rings
thalenoparacyclophanes are known as π-acids and can be
reduced chemically and electrochemically to produce the
corresponding radical anions and dianions,11,12 [3.3]paracy-
clophane behaves as a π-base to form the CT-complex with
tetracyanoethylene (TCNE) in solution and in the solid
state.13 The cyclic oligophenylene 2, like [3.3]paracyclo-
phane, forms CT-complexes with TCNE (λmax ) 638 nm)
and DDQ (λmax ) 790 nm) in CH2Cl2. Interestingly, the
oxidation potential of 2 measured by cyclic voltammetry is
fairly low (E1/2(1) ) 0.85 V vs Fc/Fc+),14 whereas 9, 10, and
12 show no oxidation peak under similar conditions.
stand nearly parallel in contrast to 1,8-diphenylnaphthalene
8
2
2
9. Each benzene carbon’s Csp -Csp contact is 2-12% shorter
than the sum of the van der Waals radii (3.40 Å). On the
other hand, the naphthalene parts indicate a splayed structure,
and the intramolecular distances (C4-C5 and C26-C27) are
2.44 and 2.45 Å, respectively, whereas the C1-C8 and C23-
C30 distances are 2.59 and 2.58 Å, respectively. Therefore,
the structure of the naphthalene parts is almost the same as
that of 3-bromo-1,8-dimethylnaphthalene.9 Noteworthy is the
high coplanarity of the benzene rings, the maximum atomic
deviations from the least-squares planes of the four benzene
rings being 0.02-0.05 Å. In contrast, the X-ray analyses of
[2.2]- and [3.3]paracyclophanes revealed bending of the
benzene rings.10 Therefore, the ring strain in 2 is mainly
released by bending six pivot bonds. The out-of-plane
deformation angles of the C-C bonds between the two
phenyl rings of the biphenyl chains have an average value
of 4.1°, and those between the phenyl and naphthalene groups
have an average value of 2.2° to the phenyl rings. Thus, 2
can be regarded as a very stable strained molecule, melting
at 460-462 °C without decomposition.
The title compound 2 and related compounds (9, 10, and
12) show strong fluorescence in solution and in the solid
state. UV and fluorescence spectra of 2, 9, 10, and 12 in
benzene are summarized in Table 1. The absorption maxima
Table 1. Fluorescence Quantum Yields and Absorption
Coefficients of 2, 9, 10, and 12
UV
fluorescence
compound
λmax/nm
ꢀ 104/M-1 cm-1
λ
max/nm
Φfa
9
12
10
2
302
304
315
313
1.23
4.30
3.49
5.67
377
389
393
427
0.11
0.34
0.41
0.12
Although strained cyclophanes and oligophenylenes such
as 1,2:9,10-dibenzo[2.2]paracyclophane-1,9-diene and naph-
(4) For general reviews, see (a) Balasubramaniyan, V. Chem. ReV. 1966,
66, 567. (b) Ko¨nig, P. Topics Curr. Chem. 1998; 196, 91.
a The quantum yield was calculated in benzene by using a 0.5 M solution
of quinine sulfate as a standard (Φf ) 0.546).
(5) All new compounds were fully characterized by spectroscopic
analyses. The selected data are as follows: 2, colorless cryst, mp 460-462
°C, EI-MS m/z 556 (M+); 1H NMR (CDCl3) δ 6.928 (8H, d, J ) 7.7 Hz),
7.104 (8H, d, J ) 7.7), 7.548 (4H, dd, J ) 7.2 and 1.3), 7.605 (4H, dd, J
) 7.8 and 7.2), 7.985 (4H, dd, J ) 7.8 and 1.3); 13C NMR (CS2:CDCl3 )
3:1) δ 124.99, 125.58, 129.03, 129.08, 130.06, 130.55, 135.35, 138.15,
139.65, 140.97; HRMS m/z calcd for C44H28 556.2191, found 556.2185.
10: colorless cryst, mp 239-240 °C, EI-MS m/z 558 (M+); 1H NMR
(CDCl3) δ 6.939-7.008 (10H, m), 6.973 (4H, d, J ) 8.3), 7.000 (4H, d, J
) 8.3), 7.456 (2H, dd, J ) 7.0 and 1.5), 7.500 (2H, dd, J ) 7.0 and 1.5),
7.580 (2H, dd, J ) 8.0 and 7.0), 7.591 (2H, dd, J ) 8.0 and 7.0), 7.981
(2H, dd, J ) 8.0 and 1.5), 7.984 (2H, dd, J ) 8.0 and 1.5); 13C NMR
(CDCl3) δ 125.14, 125.42, 125.76, 127.08, 128.33, 128.64, 128.66, 129.45,
129.96, 130.10, 130.73, 131.03, 135.44, 138.61, 140.16, 140.51, 141.80,
143.16; HRMS m/z calcd for C44H30 558.2348, found 558.2322.
(6) Ibuki, E.; Ozasa, S.; Fujioka, Y.; Mizutani, H. Bull. Chem. Soc. Jpn.
1982, 55, 845.
of 2, 9, 10, and 12 are similar, whereas 2 shows the largest
Stokes shift (114 nm), presumably due to the dimerized
structure. It is worth noting that 2 shows much lower
fluorescence quantum yield as compared to 10, although the
conformational mobility of 2 seems to be smaller than that
of 10. Further studies on the electronic structure and
properties of 2 are now under way.
Acknowledgment. We thank Dr. Hiroyuki Matsuzaka for
the measurement of X-ray analysis, Mr. Masaki Sugita, and
Prof. Haruo Inoue for the determination of fluorescence
quantum yields. Financial support by a Grant-in-Aid for
Scientific Research on Priority Areas from the Ministry of
Education, Science and Culture, Japan (11119256) is grate-
fully acknowledged.
(7) X-ray intensity data were measured on a Rigaku RAXIS-RAPID
Imaging Plate diffractometer with Mo KR radiations using a crystal with
the dimension of 0.20 × 0.40 × 0.05 mm. A total of 6571 reflections were
collected up to 2θ ) 55.0°, of which 6565 had I > -10.00σ(I), and were
used in the refinement. The crystal structure was solved by a direct method
(SIR92), expanded using Fourier techniques (DIRDIF94), and refined by
the full matrix least-squares method. All the non-hydrogen atoms were
refined anisotropically, and the hydrogen atoms were included but not
refined. Crystal data for 2: C44H28, FW ) 556.71, orthorhombic, space
group Pbca (#61), a ) 24.1982(5) Å, b ) 30.3055(7) Å, c ) 7.8559(2) Å,
V ) 5761.0(2) Å3, Z ) 8, dcalcd ) 1.284 g cm-3, R1 ) 0.044 and wR2 )
0.118 for 397 variables, GOF ) 0.62.
OL0001012
(11) de Meijere, A.; Gerson, F.; Ko¨nig, B.; Reiser, O.; Wellauer, T. J.
Am. Chem. Soc. 1990, 112, 6827; Gerson, F.; Scholz, M.; de Meijere, A.;
Ko¨nig, B.; Heinze, J.; Meerholz, K. HelV. Chim. Acta 1992, 75, 2307.
(12) Bieber, W.; Vo¨gtle, F. Angew. Chem., Int. Ed. Engl. 1977, 16, 175.
Gerson, F.; Heckendorn, R.; Mo¨ckel, R.; Vo¨gtle, F. HelV. Chim. Acta 1985,
68, 1923.
(8) House, H. O.; Koepsell, D. G.; Campbell, W. J. J. Org. Chem. 1972,
37, 1003; Vo¨gtle, F.; Papkalla, T.; Koch, H.; Nieger, M. Chem. Ber. 1990,
123, 1097.
(9) Jameson, M. B.; Penfold, B. R. J. Chem. Soc. 1965, 528.
(10) Brown, C. J. J. Chem. Soc. 1953, 3265; Lonsdale, D. K.; Milledge,
H. J.; Rao, K. V. K. Proc. R. Soc. 1960, A255, 82; Gantzel, P. K.; Trueblood,
K. N. Acta Crystallogr. 1965, 18, 958; Hope, H.; Bernstein, J.; Trueblood,
K. N. Acta Crystallogr. 1972, B28, 1733.
(13) Sheehan, M.; Cram, D. J. J. Am. Chem. Soc. 1969, 91, 3553.
(14) Cyclic voltammetric analysis: 1,2-dichlorobenzene, 0.05 M Bu4-
NPF6, glassy carbon working, Pt counter, and Ag/Ag+ reference electrodes,
298 K.
Org. Lett., Vol. 2, No. 14, 2000
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