Cyclic di[(o-polyethyleneglycoxy)phenyl]amine: New members in the crown ether family

Article abstract of DOI:10.1016/S0040-4039(00)00203-3

The synthesis of cyclic ethers based on polyethyleneglycol chains grafted on di(o-hydroxyphenyl)amine is described. The starting diarylamine is obtained from a melted salt procedure and coupled to the tosylated tri-, tetra- and pentaethyleneglycol. The X-ray crystal structure of the tetraethyleneglycol derivative was determined. For the triethyleneglycol compound, alkylation of the nitrogen atom with 5-bromomethyl-5'-methyl-2,2'- bipyridine (excess or 1 equiv.) led either to the quaternary ammonium salt or to the tertiary amine derivatives, respectively. The latter reacted with [Re(CO)₅Cl] to give the corresponding Re(I) complex in a facial configuration. (C) 2000 Elsevier Science Ltd.

Full text of DOI:10.1016/S0040-4039(00)00203-3

TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 41 (2000) 2373–2376
Cyclic di[(o-polyethyleneglycoxy)phenyl]amine: new members
in the crown ether family
Loïc J. Charbonnière and Raymond F. Ziessel ∗
Laboratoire de Chimie, d’Electronique et de Photonique Moléculaires, associé au CNRS, Ecole Chimie, Polymères,
Matériaux (ECPM), 25 rue Becquerel, 67087 Strasbourg, Cédex 02, France
Received 8 December 1999; accepted 23 January 2000
Abstract
The synthesis of cyclic ethers based on polyethyleneglycol chains grafted on di(o-hydroxyphenyl)amine is
described. The starting diarylamine is obtained from a melted salt procedure and coupled to the tosylated tri-, tetra-
and pentaethyleneglycol. The X-ray crystal structure of the tetraethyleneglycol derivative was determined. For
the triethyleneglycol compound, alkylation of the nitrogen atom with 5-bromomethyl-50-methyl-2,20-bipyridine
(excess or 1 equiv.) led either to the quaternary ammonium salt or to the tertiary amine derivatives, respectively.
The latter reacted with [Re(CO)5Cl] to give the corresponding Re(I) complex in a facial configuration. © 2000
Elsevier Science Ltd. All rights reserved.
During the development of crown ethers, cryptands, podands, coronands, calixcrowns and other
lariat ethers, polyethyleneglycol chains has proven to be highly effective for cation complexation and
recognition. A current tendency in their use as complexing agent is to graft these chelating chains directly
on fluorescent labels1 or in their close vicinity2 to obtain photoinduced electron transfer (PET) probes3
able to modulate their emissive properties in the presence of an adventitious cation.4
In this context, aminoaryl derivatives have found some interesting applications as luminophores,
but very often the aryl moieties appeared as pendent side arms and more rarely as a building part of
the complexing cavity.5,6 In an effort to produce a family of new complexing agents, we focused our
attention on the synthesis of crown ethers based on di(o-hydroxyphenyl)amines 1 as a starting synthon
(Scheme 1). Cyclization of the crown ring by the hydroxy functions on the one hand and the ability to
further functionalize the nitrogen atom on the other hand should lead to new molecules with potentially
interesting complexing properties.
The starting material 17 was obtained from o-aminophenol in a melted salt procedure under vacuum, in
the presence of hydrochloric acid (0.5 equiv.). As previously observed in other experimental conditions,8
its synthesis is accompanied by the formation of phenoxazine (8%). By treatment with 1.1 equiv. of
ditosylated tri-, tetra- and pentaethyleneglycol9 derivatives in acetonitrile containing Cs2CO3 as a base,
∗
Corresponding author. Fax: +33 3 88 13 68 95; e-mail: ziessel@chimie.u-strasbg.fr (R. F. Ziessel)
0040-4039/00/$ - see front matter © 2000 Elsevier Science Ltd. All rights reserved.
PII: S0040-4039(00)00203-3
tetl 16483

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Scheme 1. (i) HCl 0.5 equiv., melted salt, 240°C; (ii) TsOCH2(CH2OCH2)nCH2OTS, Cs2CO3, acetonitrile, 80°C, n=2 (68%),
n=3 (55%), n=4 (22%)
the corresponding cyclic diarylamines 2n (n=2, 3 and 4, respectively), were obtained.10 Recrystallization
of 23 from acetonitrile afforded colorless crystals suitable for X-ray analysis. The structure showed
that the cyclic ether crystallized with a water molecule (Fig. 1). One of the aromatic ring (including
C1) forms a plane which contains the nitrogen atom with a pronounced delocalization of the aromatic
electrons and a marked sp2 character of the nitrogen atom,11 as evidenced by the three angles C1–N–C7,
C1–N–H and H–N–C7 close to 120° (123, 117 and 118°, respectively). The plane of the second aromatic
ring is twisted [ca. 55°] by rotation around the C7–N bond. The rest of the molecule is composed of
the tetraethyleneglycol chain joining the oxygen atoms in ortho position to the nitrogen atom. When
considering the ring formed by the six heteroatoms of the crown, a water molecule is localized at
the center of this ring, slightly out of this plane and roughly equidistant with the six heteroatoms
[dN–Owater=2.901 Å, dOring–Owater=2.902 (O4) to 2.987 Å (O1 and O2)]. The water molecule is held in
place by a strong hydrogen bond involving the NH function.
Fig. 1. Top view (left) and perpendicular view (right) of the 23 macrocycle. X-Ray data (monoclinic, P121/c1, a=11.841,
b=12.323, c=13.430 Å, β=103.493°, R=0.042, Rw=0.065). Hydrogen atoms except for NH have been omitted for the sake of
clarity
In the case of 22, the ability to further functionalize the nitrogen atom was carried out by alkylation with
5-bromomethyl-50-methyl-2,20-bipyridine12 which affords the tertiary amine 32 in 38% yield (Scheme
2).13 The quaternized ammonium bromide 414 was prepared when excess of alkylating agent is used.
The same alkylation protocol could be used to prepare the crown-ether 34 (7% yield). Surprisingly, the
analogous compound 33 decomposed during the purification step but no further attempts to identify
1
the resulting compounds have been carried out. One and two dimensional H NMR spectroscopy of
the ammonium salt 4 shows a set of signals for each bipy unit and a single set for the two aryl rings
with three signals for the methylene protons of the chain, indicating the presence of a symmetry plane

2375
passing through the nitrogen atom and transforming one aryl ring into the other. For one of the bipy set,
the important deshielding observed for the signals of the methylene bridge and the proton ortho to the
nitrogen atom of the neighboring pyridine (∆δ=1.47 and 1.42 ppm, respectively, comparing to the same
signals in 32) shows these protons to be greatly affected by the ring current of the aryl moieties. Reaction
of 3n with [Re(CO)5Cl]15 in degassed toluene afforded the corresponding rhenium complex 5n in 58 and
1
30% yield after chromatography, respectively, for n=2 and 4.16 The H NMR spectrum of complex 52
is very complicated, probably as a result of the presence of different conformers at room temperature in
CDCl3, as indicated by the three different singlets observed for the methyl of the bipyridine moiety.
Scheme 2. (iii) 5-Methyl-50-bromomethyl-2,20-bipyridine (1.1 equiv. for 32 and 34, 2.2-fold excess for 4), K2CO3, acetonitrile,
80°C; (iv) [Re(CO)5Cl] (1.2 equiv.) in toluene at 80°C
In conclusion, we have developed the synthesis of novel diarylamine crown ethers and some of their
tertiary amine and quaternary ammonium derivatives. Our efforts are now directed toward the study of the
complexing properties of the non-substituted crown ethers as well as of the bipyridine-grafted derivatives.
Preliminary results showed that detection of adventitious cations is made possible by the use of steady-
state luminescence techniques. Based on this information we surmized that these molecules can work
as potential PET sensors. Further understanding of how photoinduced electron transfer processes can
be affected upon complexation is carried out using time-resolved fluorescence measurements together
with transcient absorption spectroscopy. This set of results will give a clear insight into the mechanism
of luminescence amplification. The synthetic methodology, in turn, also provides a new and efficient
avenue to cyclic diarylamines.
References
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Perkin Trans. 2 1999, 199–204.
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3. De Silva, A. P.; Gunaratne, H. Q. N.; Gunnlaugssonn, T.; Huxley, A. J. M.; McCoy, C. P.; Rademacher, J. T.; Rice, T. E.
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1
7. H NMR (CDCl3) for 1: δ 5.42 (s, 2H, OH), 5.51 (s, 1H, NH), 6.80–6.94 (m, 8H, Haro); 13C NMR (CDCl3/CD3OD, 1/1) δ
114.3, 116.6, 119.4, 120.4, 131.5, 146.6; EI/MS: m/z=201.1 (M=201.2 g mol−1 for C12H11NO2). Anal. calcd for C12H11NO2:
C, 71.62; H, 5.52; N, 6.97. Found: C, 71.34; H, 5.30; N, 6.63.
8. De Antoni, J. Bull. Soc. Chim. Fr. 1963, 2871–2873.
9. Ouchi, M.; Inoue, Y.; Kanzaki, T.; Hakushi, T. J. Org. Chem. 1984, 49, 1408–1412.
1
10. H NMR (CDCl3) for 22: δ 3.74 (s, 4H, O-CH2), 3.87–3.91 (m, 4H, O-CH2), 4.15–4.19 (m, 4H, O-CH2), 6.75–6.97 (m,
6H, Haro), 7.25 (s, br, 1H, NH), 7.47–7.51 (m, 2H, Haro). 13C NMR (CDCl3) δ 67.9, 69.5, 70.0, 111.7, 114.1, 119.4, 121.1,
133.1, 147.8. EI/MS: m/z=315.2 (M=315.4 g mol−1 for C18H21NO4). Anal. calcd for C18H21NO4: C, 68.54; H, 6.72; N, 4.44.
Found: C, 68.30; H, 6.60; N, 4.11. 1H NMR (CDCl3) for 23: δ 3.75 (s, 8H, O-CH2), 3.91–3.95 (m, 4H, O-CH2), 4.16–4.21
(m, 4H, O-CH2), 6.72 (s, br, 1H, NH), 6.80–6.89 (m, 6H, Haro), 7.37–7.43 (m, 2H, Haro). 13C NMR (CDCl3) δ 68.0, 69.9,
70.9, 71.2, 111.7, 115.8, 112.0, 120.9, 133.0, 148.4. Anal. calcd for C20H25NO5: C, 66.82; H, 7.02; N, 3.90. Found: C,
66.60; H, 6.74; N, 3.62. 1H NMR (CDCl3) for 24: δ 3.68 (s, 4H, O-CH2), 3.75 (s, 8H, O-CH2), 3.91–3.98 (m, 4H, O-CH2),
4.16–4.22 (m, 4H, O-CH2), 6.67 (s, br, 1H, NH), 6.78–6.95 (m, 6H, Haro), 7.35–7.40 (m, 2H, Haro). 13C NMR (CDCl3) δ
68.6, 70.0, 71.0, 71.2 (2C), 112.2, 116.0, 120.2, 121.2, 133.0, 148.4.
11. Andersen, K. V.; Larsen, S.; Alhede, B.; Gelting, N.; Buchardt, O. J. Chem. Soc., Perkin Trans. 2 1989, 1443–1447; Krishna
Murthy, H. M.; Bhat, T. N.; Vijayan, M. Acta Crystallogr. 1982, B38, 315–317.
12. Ziessel, R.; Hissler, M.; Ulrich, G. Synthesis 1998, 1339–1346.
1
13. H NMR (CDCl3) for 32: δ 2.37 (s, 3H, CH3), 3.63–3.71 (m, 4H, O-CH2), 3.71 (s, 4H, O-CH2), 4.10–4.16 (m, 4H, O-CH2),
3
4
4.82 (s, 2H, CH2bipy), 6.74–6.98 (m, 8H, Haro), 7.57 (dd, 1Hbipy, J=8.4 Hz, J=2.2 Hz), 8.12–8.22 (m, 3H, Hbipy), 8.46 (s,
br, 1Hbipy), 8.66 (s, br, 1Hbipy). 13C NMR (CDCl3) δ 18.4, 53.3, 67.9, 70.1, 70.6, 113.6, 120.6, 120.6, 120.8, 123.3, 123.3,
133.1, 135.5, 137.2, 137.5, 138.7, 141.7, 148.6, 149.6, 150.3, 152.7. 1H NMR (CDCl3) for 34: 2.36 (s, 3H), 3.48–3.72 (m,
3
4
3
4
16H), 4.05–4.12 (m, 4H), 5.02 (s, 2H), 6.70–6.97 (m, 8H), 7.57 (dd, 1H, J=8 Hz, J=2 Hz), 8.02 (dd, 1H, J=8 Hz, J=2
Hz), 8.21 (dd, 2H, 3J=8 Hz, 4J=2 Hz), 8.45 (s, 1H, br), 8.78 (s, 1H, br). 13C NMR (CDCl3): 18.4, 52.6, 68.3, 69.7, 70.8, 70.9,
71.1, 113.7, 120.2, 120.4, 120.5, 121.3, 123.3, 123.7, 133.1, 135.9, 137.1, 137.5, 138.3, 149.1, 149.6, 152.5, 153.7.
1
14. H NMR (CDCl3) for 4: δ 2.39 (s, 3H, CH3bipy), 2.42 (s, 3H, CH3bipy), 3.60 (s, 4H, O-CH2), 3.60–3.64 (m, 4H, O-CH2),
3.99–4.03 (m, 4H, O-CH2), 5.25 (s, 2H, CH2bipy), 6.38 (s, 2H, CH2bipy), 6.75–6.88 (m, 4Haro+1Hbipy), 6.97–7.12 (m, 4Haro),
7.54–7.63 (m, 3Hbipy), 7.81 (d, 1Hbipy, 4J=1.9 Hz), 7.99 (d, 1Hbipy, 3J=8.2 Hz), 8.11 (d, 1Hbipy, 3J=8.2 Hz), 8.26 (d, 1Hbipy
,
3J=8.0 Hz), 8.49 (m, 2Hbipy), 9.21 (dd, 1Hbipy, 3J=8.3 Hz, 4J=1.6 Hz), 9.89 (s, br, 1Hbipy). 13C NMR (CDCl3) δ 18.5, 18.7,
53.3, 59.1, 65.8, 67.7, 68.1, 111.7, 111.8, 120.7, 120.8, 121.1, 124.2, 124.5, 126.0, 129.4, 130.7, 134.1, 135.4, 136.4, 136.6,
137.7, 138.8, 142.7, 147.1, 147.7, 147.9, 149.7, 150.1, 150.2, 152.4, 152.4, 156.3. FAB/MS m/z=680 [M−Br]+. Anal. calcd
for C42H42BrN5O4: C, 66.30; H, 5.58; N, 9.21. Found: C, 66.19; H, 5.31; N, 8.91.
15. Juris, A.; Campagna, S.; Bidd, I.; Lehn, J.-M.; Ziessel, R. Inorg. Chem. 1988, 27, 4007–4011.
16. FAB/MS for 52: m/z=803.2 (M+.), 768.2 ([M−Cl]+), 315.1 ([Re(CO)3Cl]+.). IR (KBr Pellet, cm−1): 2952, 2852 (νCH2),
2021, 1905 (νCO), 1637, 1616 (νC_C, νC_N). 1H NMR (CDCl3) for 54: 2.45 (s, 3H), 3.62–3.80 (m, 16H), 4.12–4.24 (m, 4H),
3
3
5.34 (s, 2H), 6.70–6.98 (m, 6H), 7.33–7.41 (m, 2H), 7.67 (d, br, 1H, J=8 Hz), 7.96 (d, br, 2H, J=8 Hz), 8.42 (d, br, 1H,
3J=8 Hz), 8.80 (s, br, 1H), 9.33 (s, br, 1H). 13C NMR (CDCl3): 18.5, 51.6, 67.7, 69.7, 70.6, 70.7, 70.8, 112.6, 121.4, 121.7,
122.1, 123.9, 126.5, 137.1, 137.3, 139.2, 140.1, 142.0, 152.7, 153.0, 153.1, 153.8, 154.0, 197.3, 197.7 (br).]+.). IR (KBr
Pellet, cm−1): 2919, 2870 (νCH2), 2015, 1904, 1887 (νCO), 1605 (νC_C, νC_N). FAB/MS: m/z=891 (M+.), 856 ([M−Cl]+).