An amphiphilic lutetium bisphthalocyanine: Lu[(PEO)4Pc] [(DodO)4Pc]

Article abstract of DOI:10.1021/jo990793b

The synthesis of an amphiphilic lutetium bisphthalocyanine is described. One phthalocyanine of the sandwich complex bears four hydrophobic chains (C₁₂H₂₅O = DodO), and the other bears four hydrophilic polyether groups (CH₃

Full text of DOI:10.1021/jo990793b

9046
J . Org. Chem. 1999, 64, 9046-9050
An Am p h ip h ilic Lu tetiu m Bisp h th a locya n in e:
Lu [(P EO)4P c][(Dod O)4P c]
C. Cadiou,† A. Pondaven,† M. L′Her,*,† P. J e´han,‡ and P. Guenot‡
UMR 6521 “Chimie, e´lectrochimie mole´culaires et chimie analytique”, Universite´ de Bretagne Occidentale,
Faculte´ des Sciences et Techniques, B.P. 809, 29285 Brest CEDEX, France, and
Centre Re´gional de Mesures Physiques de l’Ouest, Universite´ de Rennes I, Campus de Beaulieu,
35042 Rennes CEDEX, France
Received May 13, 1999
The synthesis of an amphiphilic lutetium bisphthalocyanine is described. One phthalocyanine of
the sandwich complex bears four hydrophobic chains (C12H25O ) DodO), and the other bears four
hydrophilic polyether groups (CH3(OCH2CH2)nO ) PEO). The molecule has been characterized by
1H NMR and ESI mass spectrometry. The mean value for n, the number of polyethyleneoxy units
in the starting PEOH, is 8 with a Gaussian distribution around that value; however, for the most
abundant lutetium bisphthalocyanine, 4n ) 26. On the spectrum, the peak corresponding to the
adduct with two Na+ is higher than the one of the singly charged ion, a result of the affinity of
polyethers for alkali ions.
In tr od u ction
(LnPc2) have been obtained;10-12 however, films of better
quality are expected from suitably substituted deriv-
atives.13-15 Up to the present work, no real amphiphilic
lanthanide bisphthalocyanine has been described. Simon
and co-workers have synthesized lutetium bisphthalo-
cyanines in which the two macrocycles are hydrophobic
and the ethyleneoxy side chains are hydrophilic. This is
not really convenient for the orientation at the water/air
interface and consequently for the formation of Lang-
muir-Blodgett films on solid substrates.16 The synthetic
path to unsymmetrically substituted Ln(III) sandwich
complexes developed in our group appears to be ap-
propriate.17 This article describes the synthesis and some
properties of a lutetium bisphthalocyanine in which one
of the two macrocycles is substituted by four hydrophilic
methoxypolyethyleneoxy (PEO) chains and the second
phthalocyanine bears four hydrophobic dodecyloxy (DodO)
groups; the subsituents are connected to the macrocycles
via an ether linkage (Figure 1).
Interest in the chemistry of the phthalocyanines and
their metallic complexes is due to remarkable electronic
properties that make them particularly attractive for the
design of molecular materials for electronics and opto-
electronics.1,2 Various methods have been used to order
them as multilayers, especially the Langmuir-Blodgett
technique.3,4 Amphiphilic molecules are best suited to the
formation of well-organized films as the interaction with
the aqueous subphase is strengthened. Amphiphilic
monophthalocyanines that have been used until now bear
hydrophilic substituents on one or two of the outer
benzene rings of the macrocycle and alkyl or alkoxy
groups on the others.3-9 The characteristics of the ordered
films thus obtained vary according to the nature of the
molecular units.4
Because of their peculiar electronic properties, building
Langmuir-Blodgett films of lanthanide bisphthalocya-
nines, which requires the synthesis of an amphiphilic
sandwich complex, appeared stimulating. Multilayers of
unsubstituted bisphthalocyanines of various lanthanides
Resu lts a n d Discu ssion
Preparation of the substituted phthalonitriles is the
first stage of the synthesis. This is done by reacting
4-nitrophthalonitrile with the appropriate long-chain
alcohol in dimethylformamide (DMF) in the presence of
* Tel: (+33) 2 98 01 61 45. Fax: (+33) 2 98 01 65 94. E-mail:
Maurice.LHer@univ-brest.fr.
† Universite´ de Bretagne Occidentale.
‡ Universite´ de Rennes I.
(1) Leznoff, C. C.; Lever, A. B. P. Phthalocyanines. Properties and
Applications; VCH: New York, Vol. 1, 1989; Vol. 2, 1993; Vol. 3, 1993;
Vol. 4, 1996.
(2) McKeown, N. B. Phthalocyanine Materials; Cambridge Univer-
sity Press: Cambridge, 1998.
(3) Tredgold, R. H. J . Mater. Chem. 1995, 5, 1095 and references
therein.
(4) Cook, M. J . J . Mater. Chem. 1996, 6, 677 and references therein.
(5) Cook, M. J .; Daniel, M. F.; Harrison, K. J .; McKeown, N. B.;
Thomson, A. J . J . Chem. Soc., Chem. Commun. 1987, 1148.
(6) McKeown, N. B.; Cook, M. J .; Thomson, A. J .; Harrison, K. J .;
Daniel, M. F.; Richardson, R. M.; Roser, S. J . Thin Solid Films 1988,
159, 469.
(7) Cook, M. J .; McKeown, N. B.; Simmons, J . M.; Thomson, A. J .;
Harrison, K. J .; Richardson, R. M.; Roser, S. J . J . Mater. Chem. 1991,
1, 121.
(10) Liu, Y.; Shigehara, K.; Yamada, A. Thin Solid Films 1989, 179,
303.
(11) Petty, M. J .; Lovett, D. R.; Townsend, P.; O’Connor, J . M.; Silver,
J . J . Phys. D: Appl. Phys. 1989, 22, 1604.
(12) Clavijo, R. E.; Battisti, D.; Aroca, R.; Kovacs, G. C.; J ennings,
C. A. Langmuir 1992, 8, 113.
(13) Liu, Y.; Shigehara, K.; Hara, M.; Yamada, A. J . Am. Chem. Soc.
1991, 113, 440.
(14) (a) Rodriguez-Me´ndez, M. L.; Aroca, R.; De Saja, J . A. Chem.
Mater. 1992, 4, 1017. (b) Gorbunova, Y.; Rodriguez-Me´ndez, M. L.;
Souto, J .; Tomilova, L.; De Saja, J . A. Chem. Mater. 1995, 7, 1443.
(15) J ones, R.; Hunter, R. A.; Davidson, K. Thin Solid Films 1994,
250, 249.
(16) (a) Toupance, T.; Ahsen, V.; Simon, J . J . Am. Chem. Soc. 1994,
116, 5352. (b) Toupance, T.; Bassoul, P.; Mineau, L.; Simon, J . J . Phys.
Chem. 1996, 100, 11704.
(8) Chambrier, I.; Cook, M. J .; Cracknell, S. J .; McMurdo, J . J .
Mater. Chem. 1993, 3, 841.
(9) Cook, M. J .; McMurdo, J .; Miles, D. A.; Poynter, R. H.; Simmons,
J . M.; Haslan, S. D.; Richardson, R. M.; Welford, K. J . Mater. Chem.
1994, 4, 1205.
(17) (a) Pondaven, A.; Cozien, Y.; L’Her, M. New J . Chem. 1991,
15, 515. (b) Pondaven, A.; Cozien, Y.; L’Her, M. New J . Chem. 1992,
16, 711.
10.1021/jo990793b CCC: $18.00 © 1999 American Chemical Society
Published on Web 11/23/1999

An Amphiphilic Lutetium Bisphthalocyanine
J . Org. Chem., Vol. 64, No. 25, 1999 9047
F igu r e 1. Lu[(PEO)4Pc][(DodO)4Pc] (7).
Sch em e 1. Syn th esis of th e Su bstitu ted
P h th a lon itr iles 1 a n d 2
Sch em e 2. Syn th esis of th e P h th a locya n in es 3-6
an insoluble base, K2CO3 (Scheme 1).18,19 The carbonate,
finely powdered, is added at once to the other reactants
to avoid the formation of the usually reported byproducts,
4-hydroxyphthalonitrile and 4,4′-oxybis(phthalonitrile).20
After evaporation of DMF, 1 is recovered with the
unreacted poly(ethylene glycol)monomethyl ether (PEOH),
which will be eliminated in the second stage of the
synthesis. The phthalonitrile 2 is purified by chromatog-
raphy on a silica gel column. The lithium phthalocyanine
and the metal-free phthalocyanine have been synthesized
following an already published procedure.21, 22
Sch em e 3. Syn th esis of th e Lu tetiu m
Bisp h th a locya n in es 7-9
The purification of the phthalocyanines is much easier
when they are protonated. The hydrophilic, water soluble
derivative 3 is separated from the low molecular weight
impurities, the poly(ethylene glycol)monomethyl ether
particularly, by ultrafiltration of its aqueous solution.
Being totally insoluble in acetone, 4 is purified by
washing in a Soxhlet apparatus. The pure lithium
phthalocyanines 5 and 6 are obtained by reaction of the
metal-free phthalocyanines (3 and 4) with lithium meth-
oxide in refluxing methanol, a procedure precedently
applied to naphthalocyanines (Scheme 2).23
The amphiphilic lutetium bisphthalocyanine 7 is pre-
pared by condensation of 1 equiv of each of the lithium
monophthalocyanines 5 and 6 with 1 equiv of lutetium
acetate, in quinoline, at high temperature (Scheme 3).
After evaporation of quinoline, the residue is chro-
matographed on silica gel. The symmetrical bisphthalo-
cyanine 8, with both macrocycles bearing four dodecyloxy
substituents, is isolated by elution with pure dichlo-
romethane (yield, 22%). From a second elution with
dichloromethane/methanol (90/10 to 60/40 by volume), a
mixture of 7 and 9 is obtained. These two compounds are
separated by another chromatography on silica gel, with
a ternary mixture of solvents, dichloromethane/ethyl
acetate/methanol (60/30/10).
The amphiphilic lutetium bisphthalocyanine 7 (Figure
1) has been characterized by physicochemical methods.
This compound is paramagnetic; however, its NMR study
is possible after solubilization in deuterated DMF and
addition of hydrazine hydrate. The molecular form of 7
bears one unpaired electron (Lu3+, Pc2-, Pc•-), but its
reduced form (Lu3+, Pc2-, Pc2-) is diamagnetic.17b
Each Pc macrocycle, substituted by either four dode-
cyloxy groups or four methoxypolyethyleneoxy groups,
has four regioisomers. Of course, the sandwich complex
has many more isomers; however, it is not possible to
identify them by NMR.2 The two kinds of substituents
are linked to the aromatic ring by the same OCH2CH2
unit, and thus the methylene protons near the Pc core
(18) Keller, T. M.; Price, T. R.; Griffith, J . R. Synthesis 1980, 613.
(19) Plakhtinskii, V. V.; Abramov, I. G.; Karriskii, P. S.; Yasinskii,
O. A.; Mironov, G. S. Kinet. Catal. 1993, 34, 890.
(20) Wo¨hrle, D.; Knothe, G. Synth. Comm. 1989, 19, 3231.
(21) Hanack, M.; Gu¨l, A.; Hirsch, A.; Mandal, B. K.; Subramanian,
L. R.; Witke, E. Mol. Cryst. Liq. Cryst. Sci. Technol. 1990, 187, 365.
(22) (a) McKeown, N. B.; Painter, J . J . Mater. Chem. 1994, 4, 1153.
(b) Clarkson, G. J .; McKeown, N. B.; Treacher, K. E. J . Chem. Soc.,
Perkin Trans. 1 1995, 1817. (c) Clarkson, G. J .; Cook, M. J .; McKeown,
N. B.; Ali-Adib, Z.; Treacher, K. E. Macromolecules 1996, 29, 913.
(23) Guyon, F.; Pondaven, A.; Kerbaol, J . M.; L’Her, M. Inorg. Chem.
1998, 37, 569.

9048 J . Org. Chem., Vol. 64, No. 25, 1999
Cadiou et al.
have identical shifts (4.70 ppm). The other protons of the
dodecyl chain appear at higher field, from 0.80 to 2.30
ppm. All the methylene protons of the ethyleneoxy units
are shifted between 3.20 and 4.20 ppm, depending on
their distance to the ring. The aromatic protons on each
of the two macrocycles have approximately the same
environment; however, their signals are broad owing to
the number of isomers. The outer protons of the macro-
cycle are more shielded than usually observed,17b
a
consequence of the adjacent electron-donating dodecyloxy
or ethyleneoxy groups. The chemical shift, toward lower
fields, of the two kinds of inner protons is due to the ring
current of the two macrocycles.
Molecular analysis cannot be used for the identification
of this compound as the poly(ethylene glycol)monomethyl
ether is a mixture of chains of various lengths, O(CH2-
CH2O)nCH3. Mass spectrometry is more appropriate to
the identification of such a molecule. In a previous work,
monophthalocyanine derivatives with side chains con-
taining about 10 ethyleneoxy subunits have been studied
by fast atom bombardment mass spectrometry (FAB-
MS).22c Electrospray ionization mass spectrometry (ESI-
MS) provides a fast, sensitive, and accurate method for
high molecular mass measurements. ESI-MS has already
been used to characterize lanthanide bisphthalocyanine.24
Compounds 3 and 7, as well as the starting material
poly(ethylene glycol)monomethyl ether (PEOH), have
been studied by ESI-MS; the m/z values of the sodium
adducts [M + Na]+ are presented in Figure 2. A small
amount of potassium adducts [M + K]+ is also observed.
The peak at m/z 1645.8 (Figure 2c), corresponding to [M
+ 2Na]2+, is higher than the one of the singly charged
ion (m/z ) 3224.7, Figure 2c). [M + 3Na]3+ is present in
the spectrum of compound 9, the symmetrical lutetium
bisphthalocyanine with four PEO chains on each of the
macrocycles (see Experimental Section). Triply charged
ions are seldom observed, but PEO derivatives are known
to form complexes with alkali cations.
The mass spectra of the compounds appear like series
of peaks separated by 44 mass units for singly charged
ions (CH2CH2O) and 22 mass units for doubly charged
ions, with a Gaussian distribution around a maximum.
From Figure 2 the terms n and Σni, corresponding to the
number of ethyleneoxy subunits, are deduced for each
compound. Figure 3 represents the relative abundance
of the (CH2CH2O) subunits in PEOH, 3, and 7.
For PEOH (CH3(OCH2CH2)nOH) (Figures 2a and 3) the
maximum abundance at m/z ) 407.2 corresponds to a
number of eight ethyleneoxy subunits; however, n varies
from 4 to 15. The spectrum of the metal-free phthalo-
cyanine H2[(PEO)4Pc] 3 (Figures 2b and 3) has a maxi-
F igu r e 2. ESI MS spectra: (a) PEOH ) CH3(OCH2CH2)nOH;
(b) H2[(PEO)4Pc] (3); (c) Lu[(PEO)4Pc][(DodO)4Pc] (7).
mass measurement confirms the molecular formula of the
molecular ion (less than 2 ppm between experimental and
theoretical values), which ascertains that 7 is the asym-
metrical bisphthalocyanine. From the 1H NMR (400
MHz) spectrum, the compound is estimated to be pure.
Even if the two macrocycles of this sandwich complex
have different affinities for solvents, they are identical
from an electronic point of view because both bear OCH2-
CH2 substituents. Consequently this compound can be
considered as a symmetrical lutetium bisphthalocyanine,
formally a complex of Lu3+ with Pc2- and Pc•- (the oxi-
dized form of the phthalocyanine ring), where the un-
paired electron is delocalized over the two macrocycles.25
The UV-visible spectrum is very typical of this class of
compounds, with a Q-band maximum at 672 nm.26 The
redox potentials (CH2Cl2, 0.1 M, Bu4NPF6) of this mol-
mum m/z value at 1977.9, which indicates that Σnimax
)
30. The fact that Σnimax is not equal to 32 means that
the average distribution on the macrocyclic compound is
lower than that of PEOH, the starting material. This
could result from the purification of 3 by chromatography.
The lutetium bisphthalocyanine 7 has also been charac-
terized by ESI-MS; Σni varies for the different fractions
of 7 collected during chromatography, the highest abun-
dance for [M + Na]+ corresponding to Σni ) 26 (m/z )
3223.7, Figures 2c and 3). The experimental isotopic
distribution of the sodium adduct of 7 matches perfectly
the theoretical isotopic distribution (Figure 4). The exact
(24) J iang, J .; Liu, R. C. W.; Mak, T. C. W.; Chan, T. W. D.; Ng, D.
K. P. Polyhedron 1997, 16, 515.

An Amphiphilic Lutetium Bisphthalocyanine
J . Org. Chem., Vol. 64, No. 25, 1999 9049
This first amphiphilic lanthanide bisphthalocyanine,
7, which has been synthesized, purified, and fully char-
acterized, will be used to build up organized films at the
water-air interface and to transfer them on transparent
ITO electrodes by the technique of Langmuir-Blodgett.
Exp er im en ta l Section
Ma t er ia ls. 4-Nitrophthalonitrile was purchased from
ACROS, and 1-dodecanol and poly(ethylene glycol)monomethyl
ether 350 were purchased from Aldrich. Organic solvents were
distilled before use.
Syn th esis a n d Ch a r a cter iza tion . 4-Meth oxyp olyeth -
ylen eoxyp h th a lon itr ile (1). Finely grounded K2CO3 (2.1 g,
15.2 mmol) was added to a solution of poly(ethylene glycol)-
monomethyl ether (4.5 g, 11.7 mmol) and 4-nitrophthalonitrile
(2.0 g, 11.6 mmol) in DMF (30 mL) at 100 °C. The mixture
was stirred at this temperature for 24 h. After the mixture
cooled, distilled water (200 mL) was added, and the medium
was neutralized by a dilute aqueous solution of HCl. After
extraction by CH2Cl2 (3 times, total volume 150 mL), drying
over MgSO4, and solvent evaporation under vacuum, the
residue was purified by chromatography on a silica gel column
(70-230 mesh). The desired product was eluted by a mixture
of dichloromethane/methanol (99/1 v/v) to give 1 (2.1 g, 35%)
after solvent evaporation. It contained a small amount of
unreacted poly(ethylene glycol)monomethyl ether but it was
used in the preparation of compound 3 without further
purification: 1H NMR (400 MHz, CDCl3) δ 7.59 (d, J ) 8.8 Hz,
1H), 7.20 (d, J ) 2.4 Hz, 1H), 7.13 (dd, J ) 8.8, 2.4 Hz, 1H),
4.10 (t, J ) 4.5 Hz, 2H), 3.73 (t, J ) 4.5 Hz, 2H), 3.53 (t, J )
4.5 Hz, 2H), 3.45-3.50 (br, xH), 3.37 (t, J ) 4.5 Hz, 2H), 3.18
(s, 3H); IR (KBr) 2228, 1253, 1105 cm-1
.
4-Dod ecyloxyp h th a lon itr ile (2). Compound 2 was syn-
thesized in the same way as compound 1, with 1-dodecanol
(2.2 g, 11.8 mmol) instead of PEOH. The residue obtained after
evaporation of the organic extracts was chromatographed on
silica gel, the eluant being a mixture of toluene/hexane (80/20
v/v), to give 2 (1.1 g, 30%): 1H NMR (300 MHz, CDCl3) δ 7.70
(d, J ) 8.7 Hz, 1H), 7.25 (d, J ) 2.6 Hz, 1H), 7.17 (dd, J ) 8.7,
2.6 Hz, 1H), 4.04 (t, J ) 6.5 Hz, 2H), 1.83 (m, J ) 6.5 Hz, 2H),
1.26-1.45 (br, 18H), 0.88 (t, J ) 6.5 Hz, 3H); IR (KBr) 2230,
1250, 1095 cm-1. Anal. Calcd for C20H28ON2: C, 76.88; H, 9.03;
N, 8.97. Found: C, 76.97; H, 9.10; N, 8.92.
F igu r e 3. ESI mass spectrometry; relative abundances of
ethyleneoxy subunits in PEOH, 3, and 7.
Me t a l-F r e e
Te t r a k is(m e t h oxyp olye t h yle n e oxy)-
p h th a locya n in e (3). Under an inert atmosphere, a large
excess of lithium metal (0.28 g, 40.3 mmol) was added to a
solution of 1 (2.1 g, 4.1 mmol) in dry pentanol (50 mL). After
the lithium pentanolate formation, the mixture was refluxed
for an additional 3 h. After it cooled, the solution was poured
into acetic acid (100 mL) and heated at 100 °C for 15 min.
The solvent was removed under vacuum, and the residue was
dissolved in dichloromethane (100 mL). The organic phase was
washed with acidified water and saturated brine solution,
dried over MgSO4, and evaporated to give a green residue. The
crude product, which contained the desired compound 3 and
the unreacted poly(ethylene glycol)monomethyl ether, was
purified by ultrafiltration through an Amicon YM1 membrane
1
(cutoff 1000 Da) to afford 3 (0.9 g, 45%): H NMR (300 MHz,
CDCl3) δ 8.70-8.50 (br, 4H), 8.15-7.90 (br, 4H), 7.55-7.35
(br, 4H), 4.60-4.50 (br, 8H), 4.30-4.20 (br, 8H), 4.00-3.50 (br,
104H), 3.40-3.35 (br, 12H); ESIMS m/z (rel intensity) 1537.8
(6), 1581.9 (7), 1625.9 (9), 1669.9 (16), 1713.8 (23), 1757.8 (27),
1801.8 (49), 1845.9 (68), 1889.9 (79), 1933.9 (95), 1977.9 (100),
2022.2 (98), 2066.1 (86), 2110.1 (58), 2154.1 (47), 2198.1 (38),
2242.0 (18), 2286.1 (12), 2330.1 (6), 2374.1 (3).
Meta l-F r ee Tetr a k is(d od ecyloxy)p h th a locya n in e (4).
Compound 2 (1.1 g, 3.5 mmol) reacted with lithium metal (0.24
g, 35 mmol) in pentanol (50 mL) to give 4, following the same
synthetic path used for 3. At room temperature the metal-
free phthalocyanine precipitated in the pentanol/acetic acid
mixture. The green powder was isolated by filtration, and the
impurities were removed by extraction with acetone (200 mL)
in a Soxhlet apparatus. Compound 4 (0.35 g, 35%) was
F igu r e 4. High-resolution ESIMS of 7 (Σni ) 26): (a)
experimental isotopic distribution; (b) theoretical isotopic
distribution.
ecule are influenced by the electron-donating substituents
on the macrocycles. They are shifted to more negative
values than those of LuPc2: E°red ) -0.55 V, E°ox ) -0.19
V (-0.42 V and -0.02 V for LuPc2 vs E° (Fc+/Fc)).
(25) Chang, A. T.; Marchon, J . C. Inorg. Chim. Acta 1981, 53, L241.
(26) (a) Orti, E.; Bre´das, J . L.; Clarisse, C. J . Chem. Phys. 1990, 92,
1228. (b) Ishikawa, N.; Ohno, O.; Kaizu, Y. Chem. Phys. Lett. 1991,
180, 51.

9050 J . Org. Chem., Vol. 64, No. 25, 1999
Cadiou et al.
obtained as a green powder: 1H NMR (300 MHz, CDCl3) δ
8.25-8.00 (br, 4H), 7.70-7.40 (br, 4H), 7.20-7.00 (br, 4H),
4.30-4.10 (br, 8H), 2.10-2.00 (br, 8H), 1.80-1.30 (br, 72H),
1.00-0.90 (br, 12H). Anal. Calcd for C80H114O4N8: C, 76.76;
H, 9.18; N, 8.95. Found: C, 76.58; H, 9.29; N, 8.87.
[Tetr a k is(m eth oxyp olyeth ylen eoxy)p h th a locya n in e]-
[tetr a k is(d od ecyloxy)p h th a locya n in e] lu tetiu m (7): 1H
NMR (400 MHz, DMF-d7 + hydrazine monohydrate (1%)) δ
8.90-8.70 (br, 8H), 8.55-8.30 (br, 8H), 7.90-7.60 (br, 8H),
4.80-4.50 (br, 16H), 4.30-4.20 (br, 8H), 4.00-3.35 (br, xH),
3.30-3.20 (br, 12H), 2.30-1.25 (br, 80H), 0.90-0.85 (br, 12H);
ESIMS m/z (rel intensity) 1535.3 (26), 1557.3 (28), 1579.3 (66),
1601.3 (68), 1623.3 (90), 1645.3 (100), 1667.3 (96), 1689.4 (90),
1711.4 (76), 1733.4 (64), 1755.4 (38), 1777.4 (26), 2959.5 (9),
3003.6 (15), 3047.6 (28), 3091.6 (49), 3135.7 (58), 3179.7 (65),
3223.8 (71), 3267.8 (56), 3311.8 (46), 3355.8 (35), 3399.8 (25),
The dilithium phthalocyanines were synthesized according
to Linstead’s method with some modifications.23,27
[Tetr a k is(m eth oxyp olyeth ylen eoxy)p h th a locya n in e]
Lith iu m (5). Under an atmosphere of N2, to a stirred solution
of compound 3 (0.9 g, 0.5 mmol) in methanol (50 mL) was
added lithium metal (0.1 g, 14.4 mmol) at room temperature.
Then, after 3 h of reflux, the solvent was removed under
vacuum, and the green residue was separated from LiOH by
extraction with acetone (200 mL) in a Soxhlet apparatus. The
solution obtained was evaporated, and compound 5 (0.7 g, 80%)
was isolated as a green paste after drying under vacuum
during 24 h (50-100 °C): 1H NMR (400 MHz, acetone-d6) δ
9.25-9.15 (br, 4H), 9.00-8.80 (br, 4H), 7.60-7.50 (br, 4H),
4.60-3.45 (br, 120H), 3.30-3.20 (br, 12H).
[Tetr a k is(d od ecyloxy)p h th a locya n in e] Lith iu m (6).
The same procedure was applied to compound 4 (0.35 g, 0.3
mmol), which reacted with lithium metal (0.06 g, 8.6 mmol)
to give 6 in a good yield (0.30 g, 85%): 1H NMR (300 MHz,
acetone-d6) δ 9.30-9.05 (br, 4H), 8.95-8.70 (br, 4H), 7.60-
7.45 (br, 4H), 4.55-4.35 (br, 8H), 2.00-1.20 (br, 80 H), 0.95-
0.85 (br, 12H).
Syn th esis of th e lu tetiu m bisp h th a locya n in es 7-9. An
excess of lutetium acetate tetrahydrate (0.014 g, 0.033 mmol)
was added to a stirred mixture of 5 (0.050 g, 0.025 mmol) and
6 (0.032 g, 0.025 mmol) in freshly distilled quinoline (40 mL)
at 240 °C under nitrogen. The mixture was left for 24 h at
this temperature. After it cooled, the solution was poured on
top of a silica gel column, and elution with pure dichlo-
romethane separated compound 8 in association with quino-
line. After evaporation of quinoline, 8 (0.015 g, 22%) was
obtained pure. A second fraction eluted with dichloromethane/
methanol (from 90/10 to 60/40 v/v) gave a mixture of com-
pounds 7 and 9. This mixture was chromatographed on a
second silica gel column; the ternary mixture dichloromethane/
ethyl acetate/methanol (60/30/10 v/v/v) gave desired compound
7 (0.038 g, 47%). Finally, compound 9 (0.025 g, 27%) was eluted
from the column by dichloromethane/methanol (80/20 v/v).
3443.8 (17), 3487.9 (14); HRESIMS calcd for [C168H240N16O34
-
Na175Lu]+ 3223.6848, found 3223.6897; HRESIMS calcd for
[C170H244N16O35Na175Lu]+ 3267.7111, found 3267.7073; HRES-
IMS calcd for [C172H248N16O36Na175Lu]+ 3311.7373, found
3311.7415.
Bis[tetr a k is(d od ecyloxy)p h th a locya n in e] lu tetiu m (8):
1H NMR (300 MHz, DMF-d7 + hydrazine monohydrate (1%))
δ 8.90-8.70 (br, 8H), 8.50-8.35 (br, 8H), 7.85-7.65 (br, 8H),
4.70-4.50 (br, 16H), 2.20-1.20 (br, 160H), 0.90-0.85 (br, 24H);
HRESIMS calcd for [C160H224N16O8175Lu]+ 2672.7021, found
2672.7023.
B i s [t e t r a k i s (m e t h o x y p o ly e t h y le n e o x y )p h t h a lo -
cya n in e] lu tetiu m (9): 1H NMR (400 MHz, DMF-d7 + hy-
drazine monohydrate (1%)) δ 8.95-8.80 (br, 8H), 8.60-8.50
(br, 8H), 8.00-7.80 (br, 8H), 4.60-3.40 (br, 208H), 3.30-3.20
(br, 24H); ESIMS m/z (rel intensity) 1236.6 (17), 1251.3 (20),
1265.9 (13), 1280.6 (18), 1295.3 (29), 1309.9 (34), 1324.6
(22), 1339.3 (19), 1353.9 (18), 1368.6 (20), 1383.3 (15), 1397.9
(10), 1667.2 (18), 1689.2 (25), 1711.2 (32), 1733.3 (41), 1755.3
(52), 1777.3 (48), 1799.3 (62), 1821.2 (68), 1843.3 (72), 1865.3
(90), 1887.3 (100), 1909.3 (84), 1931.4 (72), 1953.4 (80), 1975.3
(62), 1997.4 (44), 2019.4 (42), 2041.4 (40), 2063.4 (28), 2085.4
175
(16), 2107.5 (10); HRESIMS calcd for [C170H244N16O57Na2
-
Lu]2+ 1821.2945, found 1821.2798; HRESIMS calcd for
[C172H248N16O58Na2175Lu]2+ 1843.3076, found 1843.3084; HRES-
IMS calcd for [C174H252N16O59Na2175Lu]2+ 1865.3207, found
1865.3255; HRESIMS calcd for [C176H256N16O60Na2175Lu]2+
1887.3338, found 1887.3329; HRESIMS calcd for [C178H260
-
N
16O61Na2175Lu]2+ 1909.3469, found 1909.3340; HRESIMS
calcd for [C180H264N16O62Na2175Lu]2+ 1931.3600, found
1931.3612; HRESIMS calcd for [C182H268N16O63Na2175Lu]2+
1953.3731, found 1953.3693; HRESIMS calcd for [C184H272
16O64Na2175Lu]2+ 1975.3862, found 1975.3825.
-
N
(27) Barret, P. A.; Frye, D. A.; Linstead, R. P. J . Chem. Soc. 1938,
1157.
J O990793B