Preparation and X-ray structures of trans-5,6-diaryl-5,6-dihydro-1,10- phenanthroline-5,6-diols: Formation of supramolecular rod by hydrogen bonds

Article abstract of DOI:10.1246/cl.2009.670

A series of X-ray analyses on the newly prepared title molecules have revealed that the one-dimensional rod-like structures are commonly present in the crystals of trans-dihydrophenanthrolinediols. The architecture is of interest from the viewpoint of sup

Full text of DOI:10.1246/cl.2009.670

670
Chemistry Letters Vol.38, No.7 (2009)
Preparation and X-ray Structures of trans-5,6-Diaryl-5,6-dihydro-1,10-phenanthroline-5,6-diols:
Formation of Supramolecular Rod by Hydrogen Bonds
Takanori Suzuki,ꢀ1 Youhei Miura,1 Ryuuichi Tamaki,1 Hidetoshi Kawai,1;2 and Kenshu Fujiwara1
1Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810
2PRESTO, Japan Science and Technology Agency
(Received April 14, 2009; CL-090363; E-mail: tak@sci.hokudai.ac.jp)
A series of X-ray analyses on the newly prepared title mole-
HO
Ar
OH
N
H
O
H
O
cules have revealed that the one-dimensional rod-like structures
are commonly present in the crystals of trans-dihydrophenan-
throlinediols. The architecture is of interest from the viewpoint
of supramolecular chirality because homochiral diol molecules
with the same sense of helicity are connected in a head-to-tail
fashion by a pair of NꢁꢁꢁH–O hydrogen bonds.
Ar
Ar
Ar
N
N
N
1: Ar = Ph
2: Ar = 4-PhC6H4
H
O
H
O
The hydrogen bond is one of the most important and effec-
tive tools to construct supramolecular architectures1 as has been
well established in the field of supramolecular polymers.2 Infin-
ite networks by hydrogen bonds are more frequently observed in
the designed crystal of organic solids.3 We have been interested
in constructing one-dimensional infinite rod-like structures with
a well-defined diameter from the viewpoint of possible applica-
tion to molecular wire4 in terms of molecular devices.5 We have
designed and prepared here the title diols 1 and 2 as promising
candidates to form the desired network by hydrogen bonds
(Scheme 1). Methyl ether 3 and phenanthrene derivative 4 are
also included in this study as references, in which the hydro-
gen-bond donating groups or accepting sites are missing, respec-
tively.
Ar
Ar
Me
O
Me
Ar
Ar
Ar
Ar
O
N
N
H
N
N
3: Ar = 4-PhC6H4
H
O
O
HO
Ar
OH
Ar
N
N
Double addition of PhMgBr to 1,10-phenanthroline-5,6-qui-
none6 in refluxing THF gave phenyl-diol 17 as colorless crystals
in 51% yield. No cis isomer was formed, which can be accounted
for by steric effects.8 By using 4-PhC6H4MgBr, biphenyl-diol 27
was obtained in 30% yield. Optical resolution of these racemic
diols were successfully conducted by using chiral HPLC (OA-
H H
4: Ar = 4-PhC6H4
diameter
Scheme 1.
2000 column, recycled 2–3 times, CH2Cl2 elution). Each of
D
the enantiomers obtained as the first fraction {(+)-1 (½ꢀꢂ
¼
D
þ340ꢃ, c ¼ 0:06); (+)-2 (½ꢀꢂ ¼ þ424ꢃ, c ¼ 0:26)} was later
proven to have R,R configuration for C5 and C6 asymmetric
centers.9
From biphenyl-diol (R,R)-(+)-2 was obtained biphenyl-
D
methyl ether (R,R)-(ꢄ)-37 (½ꢀꢂ ¼ ꢄ60:5ꢃ, c ¼ 0:21) in 67%
yield by successive treatment with NaH then MeI in THF at
room temperature. Another reference compound, phenan-
threne-type diol 4,7 was prepared in 66% yield by the reaction
of phenanthrenequinone with 4-PhC6H4Li in THF at ꢄ78 ꢃC.
Optically pure phenyl-diol (R,R)-(+)-1 crystallizes in a chi-
ral space group of P21212 (Z ¼ 4),10 with two crystallographi-
cally independent molecules on the 2-fold axis. One-dimension-
al rod-like networks are formed along the c axis as designed
Figure 1. Supramolecular rod structure in (R,R)-(+)-1 crystal.
equatorial positions, so that the dihydrophenanthroline skeleton
adopts P helicity (Scheme 2). This is the successful transmission
of point chirality to mobile helicity.11
Segregation of enantiomers is attained in the crystal of ra-
cemic phenyl-diol 1. Thus, the chiral supramolecular rods con-
sisting of only (P)-(R,R)-(+)-1 (P rod) or (M)-(S,S)-(ꢄ)-1 (M
rod) are also formed in the crystal of rac-1 (benzene solvate,
P42=n, Z ¼ 4)10 (Figure S1)7 as in the case of (R,R)-(+)-1 crys-
˚
(Figure 1), with a diameter of about 12 A. In this supramolecular
architecture, each molecule of (R,R)-(+)-1 is connected with two
neighbors in a head-to-tail fashion by a pair of hydrogen bonds
˚
˚
of NꢁꢁꢁH–O [d(NꢁꢁꢁH) = 2.0, 2.0 A, d(NꢁꢁꢁO) = 2.79, 3.09 A,
ꢁ(N–H–O) = 155, 173ꢃ]. The hydroxy groups, which are in-
volved in such intermolecular connection, occupy the pseudo
Copyright Ó 2009 The Chemical Society of Japan

Chemistry Letters Vol.38, No.7 (2009)
671
yl ether 3,10 molecules are rather isolated from each other with-
out any special intermolecular interactions (Figure S4).7 Lack of
inter/intramolecular hydrogen bonds may be the reason for the
change in helicity preference of 3, in which methoxy groups at
C5 and C6 occupy the pseudo axial positions.13 Such switching
in helicity would be also related to the ꢂ–ꢂ interaction between
two biphenyl groups of the pseudogauche arrangement.
In summary, we have found here that the title diols can serve
as reliable motif for the supramolecular rod. Since the homochi-
ral diols aggregate to form the one-dimensional network, the rod
structure is also chiral, thus providing the chance to further study
its supramolecular chirality.14 Studies in this vein are now in
progress and will be reported in due course along with detailed
chiroptical properties of diols 1 and 2 in solution.
(eq)HO
OH(eq)
Ar
N
Ar
N
Ar
Ar
OH(ax)
(ax)HO
5 6
5 6
N
N
(P)-(R,R)-diol
(M)-(R,R)-diol
Scheme 2.
References and Notes
1
Nanomaterials and Supramolecular Structures, ed. by A. P. Shpak,
P. P. Gorbyk, Springer, 2009.
2
a) J. M. Lehn, Makromol. Chem. Macromol. Symp. 1993, 69, 1. b) L.
Brunsveld, B. J. B. Folmer, E. W. Meijer, R. P. Sijbesma, Chem.
Rev. 2001, 101, 4071.
3
4
Design of Organic Solids, ed. by E. Weber, Springer, 1998.
F. J. M. Hoeben, P. Jonkheijm, E. W. Meijer, A. P. H. J. Schenning,
Chem. Rev. 2005, 105, 1491.
5
6
7
Chemistry of Nanomolecular Systems: Toward the Realization of
Nanomolecular Devices, ed. by T. Nakamura, T. Matsumoto, H. Tada,
K. Sugiura, Springer, 2003.
a) J. E. Dickeson, L. A. Summers, Aust. J. Chem. 1970, 23, 1023.
b) J. Frey, T. Kraus, V. Heitz, J.-P. Sauvage, Chem.—Eur. J. 2007,
13, 7584.
Figure 2. Supramolecular rod structure in (R,R)-(+)-2 crystal
(perspective view along the c axis).
Supporting Information is available electronically on the CSJ-Journal
Web site, http://www.csj.jp/journals/chem-lett/index.html.
C. Conn, R. Shimmon, Chem. Lett. 2004, 33, 78.
8
9
tal. The P and M rods are extended along the c axis and packed in
a side-by-side fashion on the ab plane. Crystallization solvent
(benzene) is clathrated in the void formed between the rod struc-
tures.
Not only phenyl-diol 1 but also biphenyl-diol 2 was proven
to form similar supramolecular rod structures as shown by the
X-ray analysis of (R,R)-(+)-2 (P21212, Z ¼ 8, two independent
molecules)10 (Figure 2). The long axis of biphenyl substituents is
nearly perpendicular to the rod direction, thus expanding the di-
Dimethyl ether (ꢄ)-3 obtained from diol (+)-2 reacted with 1,3-diio-
dopropane to give the diiodide salt of bis(quaternary) dication. Its ab-
solute configuration at C5 and C6 was successfully determined to be
R,R by the X-ray analysis using anomalous dispersion. The detail will
be reported elsewhere.
10 Selected crystal data are as follows (ref. 7). (R,R)-(+)-1: C24H18N2O2,
˚
orthorhombic, P21212, a ¼ 14:748ð2Þ, b ¼ 8:731ð1Þ, c ¼ 14:255ð2Þ A,
3
˚
V ¼ 1835:7ð8Þ A , Z ¼ 4, CCDC-725934. rac-1 benzene solvate:
˚
C
30H24N2O2, tetragonal P42=n, a ¼ b ¼ 12:196ð3Þ, c ¼ 14:114ð3Þ A,
3
˚
˚
V ¼ 2099:5ð8Þ A , Z ¼ 4, CCDC-725936. (R,R)-(+)-2: C36H26N2O2,
ameter to ca. 20 A. In the case of racemic crystal (Ibca, Z ¼ 8,
orthorhombic, P21212, a ¼ 26:610ð5Þ, b ¼ 15:281ð3Þ, c ¼ 14:146ð2Þ
molecule on the two fold axis), molecules of 2 are again connect-
ed to form the rod-like structure although homogeneity of chiral
sense in the rod is not well demonstrated due to the disorder
around the C5–C6 bond in the crystal structure (Figure S2).7
The above crystallographic data clearly show that the supra-
molecular rod-structure is commonly present in those crystals ir-
respective to the aryl groups at C5 and C6.12 Since their crystal
structures are nonisomorphic, the observed structural motif is
intrinsic to 5,6-diaryldihydrophenanthroline-5,6-diol skeleton
having two hydrogen-bond donating groups (OH) on one side
and two hydrogen-bond accepting sites (pyridine-N) on the other
side.
3
˚
˚
A, V ¼ 5752ð1Þ A , Z ¼ 8, CCDC-725935. rac-2: C36H26N2O2, ortho-
˚
rhombic, Ibca, a ¼ 24:369ð9Þ, b ¼ 15:423ð6Þ, c ¼ 14:127ð5Þ A,
3
˚
V ¼ 5309ð3Þ A , Z ¼ 8, CCDC-725937. rac-3 methanol solvate:
C40H38N2O4, monoclinic, P21=c, a ¼ 12:355ð2Þ, b ¼ 12:289ð1Þ, c ¼
ꢃ
3
˚
˚
22:113ð3Þ A, ꢃ ¼ 105:1531ð5Þ , V ¼ 3240:5ð7Þ A , Z ¼ 4, CCDC-
725938. rac-4 dichloromethane solvate: C38:5H29ClO2, monoclinic,
˚
P21=n, a ¼ 16:303ð4Þ, b ¼ 9:419ð2Þ, c ¼ 17:912ð5Þ A, ꢃ ¼
ꢃ
3
˚
91:368ð2Þ , V ¼ 2749:7ð1Þ A , Z ¼ 4, CCDC-725939.
11 a) T. Mizutani, N. Sakai, S. Yagi, T. Takagishi, S. Kitagawa, H.
Ogoshi, J. Am. Chem. Soc. 2000, 122, 748. b) T. Suzuki, S. Tanaka,
H. Kawai, K. Fujiwara, Chem. Asian J. 2007, 2, 171. c) R. Katoono,
H. Kawai, K. Fujiwara, T. Suzuki, Chem. Commun. 2008, 4906.
12 Diols with two 4-alkoxyphenyl groups at C5 and C6 positions were
also prepared. Preliminary studies on their crystal structures showed
the presence of similar supramolecular rod structure although difficulty
in obtaining a sufficiently sized single crystal hampered full analyses.
13 H. Kato, K. Ohmori, K. Suzuki, Chirality 2000, 12, 548.
14 a) G. A. Hembury, V. V. Borovkov, Y. Inoue, Chem. Rev. 2008, 108, 1.
b) A. R. A. Palmans, E. W. Meijer, Angew. Chem., Int. Ed. 2007, 46,
8948.
In fact, phenanthrene-type diol 4 without pyridine-N sites
cannot form the rod structure in the crystal although its molecu-
lar structure closely resembles that of 2: the OH groups occupy
the pseudo equatorial positions, and the R,R point chiralities are
transmitted to P helicity of dihydrophenanthrene unit. Only the
head-to-head centrosymmetric dyad is formed by the hydrogen
bond in the crystal of rac-410 (Figure S3).7 In the crystal of meth-
Published on the web (Advance View) May 30, 2009; doi:10.1246/cl.2009.670