Synthesis and cubic nonlinear optical behavior of phenyl and ferrocenyl-ended resorcinarene-based dendrimers

Article abstract of DOI:10.1016/j.tet.2008.02.050

Dendrimers were synthesized with phenyl and ferrocenyl-ended groups joined by vinyl moieties. All the dendrons used for dendrimers synthesis had showed trans configuration. This configuration as well as the 'cone' conformation of the resorcinarenes was preserved in the dendrimers, as it was shown by ¹H NMR spectroscopy. The chemical structure and purity of the synthesized dendrimers were confirmed by ¹H and ¹³C NMR, FAB+, MALDI-TOF, electrospray mass spectra, and elemental analysis. Cubic nonlinear optical behavior of this first generation of resorcinarene dendrimers was studied. The χ⁽³⁾ values estimated from the THG Maker-fringe technique for the phenyl and ferrocenyl-ended resorcinarene dendrimers dispersed in thin solid films are of the order of 10^-13 and 10^-12 esu, respectively.

Full text of DOI:10.1016/j.tet.2008.02.050

Available online at www.sciencedirect.com
Tetrahedron 64 (2008) 4460e4467
www.elsevier.com/locate/tet
Synthesis and cubic nonlinear optical behavior of phenyl and
ferrocenyl-ended resorcinarene-based dendrimers
a
Irina Victorovna-Lijanova , Maria I. Reyes-Valderrama , Jose-Luis Maldonado ,
a
b
´
´
b
Gabriel Ramos-Ortiz , Klimova Tatiana , Marcos Martınez-Garcıa
c
a,
*
´
a Instituto de Qu´ımica, UNAM, Cd. Universitaria, Circuito exterior, Coyoaca´n, C.P. 04510, Me´xico D.F., Mexico
b
´
Centro de Investigaciones en Optica, A.P. 1-948, 37000 Leo´n, Gto., Mexico
c Facultad de Qu´ımica, UNAM, Cd. Universitaria, Circuito interior, Coyoaca´n, C.P. 04510, Me´xico D.F., Mexico
Received 1 February 2008; received in revised form 12 February 2008; accepted 14 February 2008
Available online 20 February 2008
Abstract
Dendrimers were synthesized with phenyl and ferrocenyl-ended groups joined by vinyl moieties. All the dendrons used for dendrimers
synthesis had showed trans configuration. This configuration as well as the ‘cone’ conformation of the resorcinarenes was preserved in the den-
drimers, as it was shown by 1H NMR spectroscopy. The chemical structure and purity of the synthesized dendrimers were confirmed by 1H and
13C NMR, FABþ, MALDI-TOF, electrospray mass spectra, and elemental analysis. Cubic nonlinear optical behavior of this first generation of
resorcinarene dendrimers was studied. The c(3) values estimated from the THG Maker-fringe technique for the phenyl and ferrocenyl-ended
resorcinarene dendrimers dispersed in thin solid films are of the order of 10ꢀ13 and 10ꢀ12 esu, respectively.
Ó 2008 Elsevier Ltd. All rights reserved.
Keywords: Phenyl; Ferrocenyl; p-Conjugated systems; Resorcinarene; Dendrimers; Nonlinear optics
1. Introduction
absorption cross section and enabling efficient capture of
photons.6 Furthermore, both the peripheral chromophores
and the core are capable of contributing to the light absorption
properties of the entire macromolecule. Dendrimers provide
new opportunities for precisely placing some charge-carrier
transporting units in a three-dimensional nanoscale construc-
tion. Furthermore, recently the nonlinear optical (NLO) prop-
erties of several dendrimers have been reported.7e16 The use
of novel nanostructured dendrimeremetal composites for
electronic and optical applications is a very important issue
for the creation of new devices.7,8,10,12,15 These compounds
belong to the family of organometallic materials, which could
possess strong p-electron conjugation, i.e., extended electron
delocalization throughout the molecule. Since this is a crucial
factor in attaining high optical nonlinearities, it is of great in-
terest to identify and understand the structureeproperty rela-
tion of these compounds. This knowledge will contribute to
a rational design of new third-order NLO9e12,16 materials
based on low molecular weight molecules, macromolecules,
and polymers.
Luminescent and redox-active multichromophoric den-
drimers with a specific architecture are at the center of a large
interest for many reasons. They can be used to study photoin-
duced charge-separation processes and energy migration
patterns within the arrays, with the final aim of designing ef-
ficient supramolecular systems for energy conversion purposes
and/or light information devices.1 Among various luminescent
and redox-active macromolecules, p-conjugated dendrimers
and those containing organometallic fragments are particularly
attractive2e5 for the applications above because (i) their size
and architecture can be specifically controlled during the
synthesis,4 (ii) they have numerous peripheral end chains sur-
rounding a single core, (iii) the globular shape of dendrimers
provides a large surface area that can be decorated with chro-
mophores or organometallic species, thus resulting in a large
* Corresponding author.
E-mail address: margar@servidor.unam.mx (M. Martınez-Garcıa).
´
´
0040-4020/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2008.02.050

I. Victorovna-Lijanova et al. / Tetrahedron 64 (2008) 4460e4467
4461
Here we report the synthesis and cubic NLO behavior of
a novel series of ferrocenyl and phenyl ended resorcinarene-
based dendrimers with extended p-conjugated systems.
observed for all the p-conjugated systems pointing out their
trans configuration.
Resorcinarenes 10e12 were obtained from the condensa-
tion reaction of resorcinol with three different aldehydes:
hydrocinnamaldehyde, hexanal, and dodecanal (Scheme 2).
2. Results and discussion
1
Their chemical structures were confirmed by H, 13C NMR,
and FABþ mass spectrometry. The resorcinarenes showed
a well resolved triplet at dH 4.36, which is attributed to the
rccc conformation.18
2.1. Synthesis and chemical characterization of dendrons and
dendrimers
The synthesis of the two series of dendrimers with vinyl
ferrocene and stilbene was carried out applying the convergent
Frechet approach17 that consists in three steps. The first one is
´
HO
OH
HO
OH
H
HCl
Ethanol
+
C
O
R1
4
the synthesis of the two conjugated dendrons, which is fol-
lowed by the selective formation of resorcinarenes bearing
three different solubilizing groups and finally the alkylation
of the dendrons to the resorcinarenes. Under this order,
dendrons containing styryl and ferrocenylvinyl groups were
prepared starting from a Heck reaction coupling of the com-
mercially available 3,5-dibromo-benzaldehyde 3 with styrene
1 or vinyl ferrocene 2 in dimethylformamide/triethylamine
(1:0.25) using palladium acetate as catalyst (Scheme 1).
Both compounds 4 and 5 were obtained in 60% yield. They
have E-configuration as it was evidenced by the high value
(ca. 16 Hz) of the coupling constant for the AB system of
the vinylic protons. Aldehydes 4 and 5 were reduced with
LiAlH4 in THF to give alcohols 6 and 7 in 90 and 99% yield,
respectively, which were converted into chlorides 8 and 9 upon
treatment with thionyl chloride and pyridine in dichlorome-
thane. Dendrons 8 and 9 are the first generation dendrons of
the stilbene and vinylferrocenyl families (Scheme 1).
R1
R1= -(CH2)2-C6H5 (10)
-(CH2)4-CH3 (11)
-(CH2)10-CH3 (12)
Scheme 2. Synthesis of resorcinarenes 10e12.
The iterative convergent strategy used for the synthesis of
functionalized dendrimers is depicted in Scheme 3. The syn-
thesis of dendrimers involves only one step, an O-alkylation
between dendrons 8 or 9 and resorcinarenes 10e12. The reac-
tion was carried out in acetone and K2CO3 at reflux for 7 days
and the dendrimers were obtained in good yields.
The 1H NMR spectra of the dendrimers 13e15 showed one
triplet at dH 5.10, 4.93 and 5.32, respectively, assigned to the
methine proton at the resorcinarene bridges. These triplets
confirm that the resorcinarene dendrimers have an rccc confor-
mation, while that ascribed to the eCH2eO protons appears as
a broad signal at dH 4.75, 4.63, and 4.76. For all dendrimers
13e15, the vinylic protons give two doublets, at dH 6.79 and
6.89 both with a couplet constant J¼16.2 Hz (Fig. 1a) for den-
drimer 13, at dH 6.80 and 6.89 with a couplet constants J¼16.2
and 16.1 Hz, respectively, for dendrimer 14, at dH 7.05 and
7.14 with a couplet constants J¼16.2 and 16.5 Hz, respec-
tively, for dendrimer 15. In all cases a broad peak is also
observed at dH 7.15e7.52 assigned to the aromatic protons.
1
The structure of dendrons 8 and 9 was confirmed by H
NMR spectroscopy. Signals at dH 4.63 (dendron 8) and 4.61
(dendron 9) corresponded to the methylene protons
AreCH2eCl. Compound 9 showed three signals at dH 4.17,
4.32, and 4.59 due to the ferrocenyl groups. The vinylic pro-
tons were observed as two doublets at dH 7.13 and 7.15 for
compound 8 and at dH 6.69 and 6.94 for compound 9. The
broad signals for the aromatic protons appear at dH 7.23e
7.58. The coupling constants of ca. J¼15.4e16.8 Hz were
1
The H NMR spectra of dendrimers 16e18 showed the char-
acteristic signals due to the ferrocenyl groups at dH 4.13, 4.14,
Cl
OH
O
O
c
a
b
+
Br
Br
3
8
6
4
1
Cl
OH
O
O
c
a
b
+
Br
Br
9
5
3
7
Fe
Fe
Fe
Fe
Fe
Fe
Fe
2
Scheme 1. Synthesis of dendrons 8 and 9: (a) Pd(OAc)2/tri-o-tolylphosphine, DMF/Et3N, 120 ꢁC, 24 h; (b) THF, LiAlH4, 0 ꢁC, 4 h; (c) Py, CH2Cl2,
SOCl2, ꢀ10 ꢁC, 7 h.

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I. Victorovna-Lijanova et al. / Tetrahedron 64 (2008) 4460e4467
Cl
Dendrimers
Acetone, reflux
OH
R1
K2CO3, 18-C-6
HO
13, 14, 15
8
Cl
+
4
Acetone, reflux
K2CO3, 18-C-6
R1= -(CH2)2-C6H5 (10)
-(CH2)4-CH3 (11)
-(CH2)10-CH3 (12)
Dendrimers
16, 17, 18
Fe
Fe
9
Fe
Fe
Fe
Fe
Fe
Fe
O
O
O
O
Fe
O
O
O
O
O
Fe
Fe
O
O
O
Fe
O
O
O
O
Fe
Fe
Fe
Fe
Fe
Fe
16
13
Scheme 3. Synthesis of resorcinarene dendrimers 13e18.
and 4.47 and due to the CH2eO at dH 4.14. One broad signal at
dH 4.70 was assigned to the methine groups CH, and two broad
signals at dH 7.07e7.46 were assigned to the aromatic protons.
For the dendrimers 16e18 in all the cases four sets of signals
for the vinylic protons were observed: at dH 6.56, 6.68, 6.87,
6.91 with a couplet constants J¼15.6, 15.9, 15.6, 16.2 Hz for
the dendrimer 16, at dH 6.69, 6.71, 6.90, 6.94 with a couplet
constants J¼16.5, 15.9, 15.6, 15.6 Hz for the dendrimer 17
(Fig. 1b), at 6.69, 6.73, 6.87, 6.91 with a couplet constants
J¼16.2, 15.9, 15.6, 15.9 Hz for the dendrimer 18. The four
set of signals two small and two bigger for the vinylic protons
in the ferrocenyl terminating dendrimers could be due to the
presence two types of conformations the boat C2v and the
crown C4v symmetry and their slow interconvertion. This re-
sorcinarene dendrimers behavior also was reported by Ueda
and co-workers.18 Similar results were observed in the 1H
NMR spectra of resorcinarene when it has bulky substituents.18
The structures of dendrimers 13e18 were also confirmed
by 13C NMR, IR, and electrospray, MALDI-TOF mass spec-
trometry. It was found that all the dendrimers have an expected
molecular weight. The MALDI-TOF mass spectra of
dendrimer 15 and electrospray mass spectra of 18 are shown
in Figure 2.
2.2. Linear and third-order nonlinear optical
characterization
In this work, the cubic NLO response for the series of
phenyl and ferrocenyl-ended resorcinarene dendrimers (com-
pounds 13e18) was estimated through the use of third-har-
monic generation (THG) Maker-fringes technique.19 This
technique was chosen to measure c(3) because it allows mea-
suring pure electronic NLO effects (important for high band-
width photonic applications). Figure 3 shows the linear

I. Victorovna-Lijanova et al. / Tetrahedron 64 (2008) 4460e4467
4463
Figure 1. Aromatic portion of the 1H NMR spectrum of dendrimers 13 (a) and
17 (b) in CDCl3 at room temperature. The vinylc groups are indicated by stars.
absorption (absorption coefficient) of the dendrimers doped
into solid polystyrene (PS) films at a loading level of
30 wt % (weight percent). Sample thickness was between
140 nm and 1.6 mm.
Figure 2. MALDI-TOF and electrospray mass spectra of phenyl 15 (a) and
ferrocenyl 18 (b) ended resorcinarene dendrimers.
The films show a broad absorption band with maxima
around 300e312 nm. These compounds exhibit high transpar-
ency in the visible and IR wavelength regions. Figure 4 shows
the so called THG Maker-fringe patterns for the compound 16
doped into PS film (sample thickness: 144 nm). As reference,
the figure also includes the THG patterns measured from the
fused silica substrate alone (thickness: 1 mm). These data
were obtained at the fundamental near infrared wavelength
of 1200 nm (THG signal at 400 nm). From these data it is
estimated that the third-order nonlinear susceptibility of the
polymer film doped with compound 16 is of the order of
10ꢀ12 esu at such fundamental wavelength. Table 1 shows
c(3) values for the compounds studied. We could not prepare
good quality samples with dendrimer 15 and so, the corre-
sponding c(3) value is not reported.
From our measurements it is evident that for this series of
dendrimers, the cubic susceptibilities c(3) are clearly improved
with the addition of the ferrocenyl-ended group 16e18. Previ-
ously, c(3) values of the order of 10ꢀ10e10ꢀ12 esu were re-
ported for some others dendrimers.12,14 However, in these
works12,14 different NLO techniques were used such as degen-
erate four wave mixing (DFWM),12 Z-scan, and self-phase
modulation.14 Also, in the last reference, samples were tested
in solution and a femtosecond laser system was used for the
excitation. For some particular dendrimers with CdS quantum
Figure 3. Optical linear absorption coefficient of polymer films doped with
phenyl and ferrocenyl-ended resorcinarene dendrimers; 13 (filled squares),
14 (filled circles), 15 (filled stars), 16 (open circles), 17 (open squares), and
18 (open stars). The inset shows the transparency of these films in the visible
and infrared wavelength region.

4464
I. Victorovna-Lijanova et al. / Tetrahedron 64 (2008) 4460e4467
preserved in the dendrimers, as well as the cone conformation
of the resorcinarene core as it was observed by 1H NMR
spectroscopy. The chemical structure and purity of the synthe-
1
sized dendrimers have been confirmed by H and 13C NMR,
FABþ, MALDI-TOF and electrospray mass spectra, and
elemental analysis. The c(3) values estimated from the THG
Maker-fringe technique for our synthesized molecules are of
the order of 0.5ꢂ10ꢀ12 esu for the phenyl ended resorcinarene
dendrimers and this nonlinearity is increased in about a factor
of five when the phenyl group is substituted by a ferrocenyl
group.
4. Experimental section
4.1. Materials and equipments
Solvents and reagents were purchased as reagent grade and
used without further purification. Acetone was distilled over
calcium chloride. Tetrahydrofuran was distilled from sodium
Figure 4. THG Maker-fringe patterns for 144-nm thin polymer film doped with
30 wt % of compound 16 (solid line) and for a 1-mm thick substrate without
a film deposited on it (open circles). The fundamental wavelength is 1200 nm.
and benzophenone. Column chromatography was performed
on Merck silica gel 60 A (70e230 mesh). H and 13C NMR
1
˚
were recorded on a Varian-Unity-300 MHz with tetramethylsi-
lane (TMS) as an internal reference. Infrared (IR) spectra were
measured on a spectrophotometer Nicolet FT-SSX. Elemental
analysis was determined by Galbraith Laboratories, INC
Knoxville. FABþ mass spectra were taken on a JEOL JMS
AX505 HA instrument. Electrospray mass spectra were taken
on a Bruker Daltonic, Esquire 6000. MALDI-TOF mass spec-
tra were taken on a Bruker Omni FLEX. The nonlinear optical
measurements were performed in solid state (solid films) using
the guest (molecule)ehost (polymer) approach. Mixtures of
polystyrene (PS) and dendrimer 70:30 wt % ratio, respectively,
were dissolved in dichloromethane. The solid films were
deposited on fused silica substrates (1 mm-thick) by using
the spin coating technique. The prepared films had typical
thickness between 100 and 500 nm with good optical quality.
Absorption spectra of spin-coated films were obtained with
a spectrophotometer (PerkineElmer Lambda 900). Sample
thickness was measured by using a Dektak 6M profiler.
Table 1
c(3) values for dendrimers 13e18
Sample (30 wt % into PS)
(10ꢀ12 esu)a
13
14
15
16
17
18
0.55
0.50
d
2.6
2.3
1.9
Fundamental wavelength: 1200 nm.
c(3) for fused silica¼3.1ꢂ10ꢀ14 esu.
a
dots, c(3) of the order of 10ꢀ9 esu was obtained by Z-scan
technique with a picosecond laser system.16
Because of the above reasons it is difficult to compare the
c(3) absolute values obtained in the present work employing
the THG Maker-fringe technique for solid dendrimers-con-
taining polymer films with others reported in the literature.
However, the results obtained in the present study for the
two series of resorcinarene dendrimers (Table 1) clearly
show a great improvement in c(3) values when adding the
phenyl and ferrocenyl-ended dendrimers with the ethylphenyl
resorcinarene cores 13 and 16, respectively, showed for the
series of ferrocenyl ended dendrimers in comparison with
phenyl ended ones. In addition, for both series studied, the
best c(3) values inside each series this were obtained for the
dendrimers with the ethylphenyl resorcinarene cores (13 and
16, respectively). This could be due the presence of four
more phenyl group in these dendrimers.
4.2. Synthesis of dendrons
A mixture of 1 or 2 (3.8 mmol), 3 (1.89 mol), Pd(OAc)2
(1.3 mmol), and tri-o-tolylphosphine POT (3.28 mmol) in
Et3N/DMF 1:5 (120 mL) was stirred under N2 at 120 ꢁC for
24 h. After cooling, the resulting mixture was filtered and
the solvents evaporated. The crude product was purified by
column chromatography (SiO2, hexane).
4.2.1. (E)-3,5-Distyrylbenzaldehyde 4
Yield 5.4 g (60%), white powder, mp 125e127 ꢁC, UV
CH2Cl2 (nm): 242, 311. IR (KBr, cmꢀ1): 3443, 3025, 2809,
2738, 1695 (C]O), 1590, 1449, 1143, 966, 884, 743, 694,
528. 1H NMR (300 MHz, CDCl3) dH (ppm): 7.13 (d, 2H,
CH], J¼16.5 Hz), 7.23 (d, 2H, CH], J¼16.5 Hz), 7.27e
7.45 (m, 4H, Ar), 7.35 (t, 2H, Ar, J¼1.6 Hz), 7.54e7.60 (m,
4H, Ar), 7.87 (t, 2H, Ar, J¼2.0 Hz), 7.92 (s, 1H, Ar), 10.09
3. Conclusions
The first generation of resorcinarene dendrimers with phe-
nyl and ferrocenyl-ended groups joined by vinyl moieties was
synthesized by convergent building method with good yields.
All dendrons showed trans configuration, and this was

I. Victorovna-Lijanova et al. / Tetrahedron 64 (2008) 4460e4467
4465
(s, 1H, HC]O). 13C NMR (75 MHz, CDCl3) dC (ppm): 126.2
(CH]), 126.7 (Ar), 127.0 (CH]), 128.2 (Ar), 128.8 (Ar),
130.2 (Ar), 130.7 (Ar), 136.6 (Aripso), 137.2 (Aripso), 138.7
(Ar), 192.2 (C]O). MS (m/z): 310. Anal. Calcd for
C23H18O: C, 89.00; H, 5.85%. Found: C, 89.10; H, 5.86%.
Compound 6 or 7 (14.0 mmol), pyridine 1 mL (14.0 mmol),
and 1.45 mL (14.0 mmol) of SOCl2 were dissolved in 100 mL
of dry CH2Cl2, then this mixture was cooled to ꢀ10 ꢁC. The
reaction was carried out in nitrogen atmosphere in ice bath
for 7 h. After this period, the solvent was evaporated and the
resulting oil was dry supported and purified in a silica gel
(60e240 pore size) column using a mixture of hexane/
dichloromethane (2:1) as eluent.
4.2.2. (E)-3,5-(Divinylferrocenyl)benzaldehyde 5
Yield 0.8 g (60%), red powder, mp 159e162 ꢁC, UV
CHCl3 (nm): 458, 314, 248. IR (KBr, cmꢀ1): 3085, 2928,
2806, 1693, 1632, 1589, 1303, 1103, 962, 813, 487. 1H
NMR (300 MHz, CDCl3) dH (ppm): 4.16 (s, 10H, C5H5),
4.32 (s, 4H, C5H4), 4.50 (s, 4H, C5H4), 6.75 (d, 2H, ]CH,
J¼16.2 Hz), 7.02 (d, 2H, ]CH, J¼15.9 Hz), 7.65 (s, 2H,
Ar), 7.79 (s, 1H, Ar), 10.05 (s, 1H, O]CeH). 13C NMR
(75 MHz, CDCl3) dC (ppm): 67.0 (C5H4), 69.2 (C5H5), 69.3
(C5H4), 82.5 (Aripso), 124.3 (Ar), 124.6 (]CH), 128.9 (Ar),
129.1 (]CH), 137.1 (Aripso), 139.1 (Aripso), 192.6 (O]Ce
H). MS (m/z): 526. Anal. Calcd for C31H26Fe2O: C, 70.72;
H, 4.94; Fe, 21.29%. Found: C, 70.72; H, 4.49; Fe, 21.27%.
Lithium aluminum hydride (97%, 15.2 mmol) was dis-
solved in 50 mL of dry THF. To this emulsion, 6.4 mmol of
4 or 5 dissolved in 15 mL of dry THF was added dropwise us-
ing an addition funnel. The reaction was carried at 0 ꢁC for
4 h. After this time, 10 mL of water was added and the reac-
tion mixture was filtered in CeliteÒ. The solvent was evapo-
rated and the residue was dissolved in dichloromethane. The
resulting solution was dried with sodium sulfate, filtered and
the product was vacuum dried, and purified by column chro-
matography (Al2O3, hexane).
4.2.5. (E)-1-(Chloromethyl)-3,5-distyrylbenzene 8
Yield 4.1 g (95%), yellow-brown powder, mp 106e108 ꢁC,
UV CHCl3 (nm): 242, 302. IR (KBr, cmꢀ1): 3026, 2924, 2953,
1596, 1493, 1450, 1261, 1155, 960, 750, 691. 1H NMR
(300 MHz, CDCl3) dH (ppm): 4.63 (s, 2H, CH2eCl), 7.13
(d, 2H, CH], J¼16.4 Hz), 7.15 (d, 2H, CH], J¼16.6 Hz),
7.23e7.52 (m, 10H, Ar), 7.55 (t, 2H, Ar, J¼2.5 Hz), 7.58 (t,
1H, Ar J¼1.5 Hz). 13C NMR (75 MHz, CDCl3) dC (ppm):
46.1 (CH2eCl), 124.7 (Ar), 125.6 (Ar), 126.5 (Ar), 127.8
(CH]), 129.6 (Ar), 136.9 (Aripso), 138.1 (Aripso), 138.2
(Ar). MS (m/z): 330. Anal. Calcd for C23H19Cl: C, 83.50; H,
5.79%. Found: C, 83.56; H, 5.78%.
4.2.6. (E)-1-(Chloromethyl)-3,5-divinyl-diferrocenyl-
benzene 9
Yield 2.9 g (39%) as a red powder, Tdecomp. 178e190 ꢁC, UV
CHCl3 (nm): 447, 312, 272, 242. IR (KBr, cmꢀ1): 3360, 3059,
3010, 2925, 1707, 1567, 1448, 1216, 1167, 1106, 1138, 810,
1
757. H NMR (300 MHz, CDCl3) dH (ppm): 4.17 (s, 10H,
C5H5), 4.32 (s, 4H, C5H4), 4.59 (s, 4H, C5H4), 4.61 (s, 2H,
CH2eCl), 6.69 (d, 2H, ]CH, J¼15.5 Hz), 6.93 (d, 2H, ]CH,
J¼15.4 Hz), 7.33 (s, 2H, Ar), 7.42 (s, 1H, Ar). 13C NMR
(75 MHz, CDCl3) dC (ppm): 46.2 (H2CeCl), 66.8 (C5H5),
69.1 (C5H4), 69.2 (C5H4), 83.1 (Aripso), 122.7 (Ar), 125.27
(]CH), 125.5 (Ar), 127.7 (]CH), 132.8 (Aripso), 143.3
(Aripso). MS (m/z): 547. Anal. Calcd for C31H27ClFe2: C, 68.13;
H, 4.94; Fe, 20.51%. Found: C, 68.13; H, 4.94; Fe, 20.48%.
The resorcinarenes were obtained in agreement with
reference.8
4.2.3. (E)-3,5-(Distyrylphenyl)methanol 6
Yield 1.8 g (90%), white powder, mp 130e132 ꢁC, UV
CH2Cl2 (nm): 241, 302. IR (KBr, cmꢀ1): 3370, 3025, 2883,
1
1595, 1493, 1449, 1029, 961, 750, 693. H NMR (300 MHz,
CDCl3) dH (ppm): 4.75 (s, 2H, CH2), 5.18 (s, 1H, OH), 7.15
(s, 2H, CH]), 7.16 (s, 2H, CH]), 7.23e7.44 (m, 10H, Ar),
7.51 (d, 2H, Ar, J¼1.5 Hz), 7.55 (t, 1H, Ar, J¼1.5 Hz). 13C
NMR (75 MHz, CDCl3) dC (ppm): 65.2 (CH2eOH), 124.0
(Ar), 124.2 (Ar), 126.5 (Ar), 127.7 (CH]), 128.1 (CH]),
128.7 (Ar), 129.2 (Ar), 137.1 (Aripso), 138.0 (Aripso), 141.6
(Ar). MS (m/z): 312. Anal. Calcd for C23H20O: C, 88.46; H,
6.41%. Found: C, 88.49; H, 6.38%.
4.3. Synthesis of dendrimers
A mixture of 1 mmol of the respective dendron 8 or 9,
potassium carbonate (21.2 mmol), and 18-crown-6 (0.56 g,
2.12 mmol) in dry acetone (80 mL) was heated to reflux and
stirred vigorously in nitrogen atmosphere for 20 min. The
compounds 10e12 (0.0125 mmol) dissolved in dry acetone
(40 mL) were added dropwise and the reaction was continued
for 7 days. The mixture was allowed to cool and the precipitate
was filtered. The filtrate was evaporated to dryness under
reduced pressure. The residue dissolved in diethyl ether was
washed with an aqueous solution of 5% Na2CO3 (three times).
The organic layer was dried and evaporated to dryness and the
dendrimers were purified using the following procedure: the
dendrimer was dissolved in CH2Cl2, then methanol was added
producing the precipitation of the dendrimer back. This proce-
dure was repeated three times.
4.2.4. (E)-3,5-((Divinylferrocenyl)phenyl)methanol 7
Yield 3.3 g (99%), red powder, mp 173e175 ꢁC, UV
CHCl3 (nm): 455, 312, 265, 243. IR (KBr, cmꢀ1): 3329,
2926, 1592, 1451, 1169, 1136, 808, 718, 690. 1H NMR
(300 MHz, CDCl3) dH (ppm): 2.49 (s, 1H, eOH), 4.17 (s,
10H, C5H5), 4.32 (s, 4H, C5H4), 4.51 (s, 4H, C5H4), 4.73 (s,
2H, CeOH), 6.69 (d, 2H, ]CH, J¼15.5 Hz), 6.93 (d, 2H,
]CH, J¼15.4 Hz), 7.33 (s, 2H, Ar), 7.42 (s, 1H, Ar). 13C
NMR (75 MHz, CDCl3) dC (ppm): 65.4 (CeOH), 67.0
(C5H5), 69.3 (C5H4), 69.5 (C5H4), 83.1 (Aripso), 122.7 (Ar),
125.4 (]CH), 125.9 (Ar), 127.5 (]CH), 132.9 (Aripso),
143.6 (Aripso). MS (m/z): 528. Anal. Calcd for C31H28Fe2O:
C, 70.45; H, 5.30; Fe, 21.21%. Found: C, 70.43; H, 5.33;
Fe, 21.19%.

4466
I. Victorovna-Lijanova et al. / Tetrahedron 64 (2008) 4460e4467
4.3.1. Dendrimer 13
32H, C5H4), 4.47 (s, 32H, C5H4), 4.68 (br, 4H, CH), 6.56 (s,
4H, Ar), 6.68 (d, 8H, ]CH, J¼15.9 Hz), 6.71 (d, 8H, ]CH,
J¼15.9 Hz), 6.85 (s, 4H, Ar), 6.91 (d, 8H, ]CH, J¼16.2 Hz),
7.30 (br, 36H, Ar), 7.46 (br, 8H, Ar). 13C NMR (75 MHz,
CDCl3) dC (ppm): 29.1 (eCH2), 66.8 (C5H4), 69.1 (C5H5),
69.9 (OeCH2), 83.1 (Cipso), 122.5 (Ar), 124.1 (Ar), 125.6
(CH]), 127.1 (CH]), 127.3 (Ar), 128.8 (Aripso), 138.3
(Aripso), 141.6 (Aripso). Electrospray (m/z): 4984. Anal. Calcd
for C308H246Fe16O8: C, 74.15; H, 5.29; Fe, 17.97%. Found: C,
74.16; H, 5.27; Fe, 17.99%.
Yield 0.40 g (91%), brown-red powder, mp >300 ꢁC, UVe
vis CH2Cl2 (nm): 241.5, 301.5. IR (KBr, cmꢀ1): 3429, 3025,
2925, 2861, 1943, 1798, 1597, 1494, 1452, 1376, 1294, 1180,
1
1105, 959, 749, 692, 534. H NMR (300 MHz, CDCl3) dH
(ppm): 2.38 (br, 8H, CH2), 2.77 (br, 8H, CH2), 4.75 (m, 16H,
CH2eO), 4.78 (t, 4H, CH, J¼7.0 Hz), 6.64 (s, 4H, Ar), 6.79
(d, 16H, CH], J¼16.2 Hz), 6.89 (d, 16H, CH], J¼16.2 Hz),
6.99 (s, 4H, Ar), 7.14e7.52 (m, 124H, Ar). 13C NMR
(75 MHz, CDCl3) dC (ppm): 35.0 (CH), 36.3 (CH2), 37.1
(CH2), 70.0 (CH2eO), 70.8 (CH2eO), 123.5 (Ar), 124.7 (Ar),
125.3 (Ar), 126.5 (CH]), 127.0 (Ar), 127.5 (Ar), 128.1 (Ar),
128.2 (Ar), 128.6 (Ar), 128.8 (Ar), 129.2 (Ar), 137.0 (Aripso),
137.4 (Aripso), 137.9 (Ar), 142.5 (Aripso), 155.2 (AreO). Elec-
trospray (m/z): 3260. Anal. Calcd for C244H200O8: C, 89.89;
H, 6.18%. Found: C, 89.90; H, 6.17%.
4.3.5. Dendrimer 17
Yield 0.50 g (78%), brown powder, mp >300 ꢁC, UV
CHCl3 (nm): 449, 311, 246. IR (KBr, cmꢀ1): 3358, 3094,
3010, 2924, 2858, 1707, 1633, 1593, 1499, 1468, 1454,
1410, 1376, 1351, 1285, 1248, 1218, 1173, 1108, 1043,
1
1026, 1001, 961, 931, 835, 819, 754. H NMR (300 MHz,
4.3.2. Dendrimer 14
CDCl3) dH (ppm): 0.87 (br, 12H, CH3), 1.25 (br, 32H, CH2),
4.14 (br, 80H, C5H5, 16H, CH2eO), 4.29 (br, 64H, C5H4),
4.73 (br, 4H, CH), 6.62 (br, 4H, Ar), 6.69 (d, 8H, ]CH,
J¼16.5 Hz), 6.71 (d, 8H, ]CH, J¼15.9 Hz), 6.90 (d, 8H,
Ar, J¼15.6 Hz), 6.94 (d, 8H, Ar, J¼15.6 Hz), 7.29 (br, 4H,
Ar), 7.35e7.64 (br, 16H, Ar), 7.46 (br, 8H, Ar). 13C NMR
(75 MHz, CDCl3) dC (ppm): 14.1 (CH3), 22.6 (CH2), 28.0
(CH2), 32.1 (eCH2), 66.9 (C5H4), 69.2 (C5H5), 70.0
(OeCH2), 83.2 (Fcipso), 122.5 (Ar), 124.1 (Ar), 125.7 (Ar),
127.4 (CH]), 127.2 (Ar), 129.3 (CH]), 131.9 (Aripso),
138.5 (Cipso), 140.5 (Aripso). Electrospray (m/z): 4849. Anal.
Calcd for C296H272Fe16O8: C, 73.25; H, 5.60; Fe, 18.47%.
Found: C, 73.25; H, 5.62; Fe, 18.46%.
Yield 0.60 g (91%), brown powder, mp >300 ꢁC, UVevis
CH2Cl2 (nm): 242.5, 302, 391. IR (KBr, cmꢀ1): 3430, 3026,
2924, 2853, 1780, 1703, 1596, 1494, 1456, 1173, 1107, 961,
750, 694. 1H NMR (300 MHz, CDCl3) dH (ppm): 0.68 (t,
12H, CH3, J¼4.5 Hz), 1.23 (br, 16H, CH2), 2.02 (br, 16H,
CH2), 4.63e4.87 (m, 16H, CH2eO), 4.93 (m, 4H, CH), 6.65
(s, 4H, Ar), 6.80 (d, 16H, CH], J¼16.2 Hz), 6.89 (d, 16H,
CH], J¼16.1 Hz), 6.96 (s, 4H, Ar), 7.15e7.5 (br, 104H,
Ar). 13C NMR (75 MHz, CDCl3) dC (ppm): 14.0 (CH3), 22.7
(CH2), 32.3 (CH2), 34.6 (CH), 69.9 (CH2eO), 123.5 (Ar),
124.0 (Ar), 124.7 (Ar), 126.5 (Ar), 127.5 (CH]), 128.2
(Ar), 128.5 (Ar), 137.1 (Aripso), 137.4 (Aripso), 138.0 (Aripso),
155.1 (AreO). Electrospray (m/z): 3121. Anal. Calcd for
C
232H208O8: C, 89.19; H, 6.71%. Found: C, 89.20; H, 6.71%.
4.3.6. Dendrimer 18
Yield 0.56 g (83%), brown powder, mp >300 ꢁC, UV
CHCl3 (nm): 453, 311, 235. IR (KBr, cmꢀ1): 3380, 3090,
3027, 2920, 2855, 1706, 1631, 1591, 1497, 1459, 1410, 1352,
4.3.3. Dendrimer 15
Yield 0.36 g (85%), brown powder, mp >300 ꢁC, UVevis
CH2Cl2 (nm): 242.5, 301.5. IR (KBr, cmꢀ1): 3446, 3055,
3025, 2860, 1623, 1596, 1495, 1453, 1400, 1279, 1180, 1110,
1
1287, 1246, 1183, 1107, 1047, 1001, 958, 819, 697, 488. H
NMR (300 MHz, CDCl3) dH (ppm): 0.85 (br, 12H, CH3),
1.22 (br, 56H, CH2), 1.25 (br, 8H, CH2), 2.18 (br, 8H, CH2),
2.63 (br, 8H, CH2), 4.10 (br, 80H, C5H5, 16H, OeCH2), 4.29
(br, 32H, C5H4), 4.46 (br, 32H, C5H4), 4.74 (br, 4H, CH),
6.60 (br, 4H, Ar), 6.69 (d, 8H, ]CH, J¼16.2 Hz), 6.73 (d,
8H, ]CH, J¼15.9 Hz), 6.87 (d, 8H, Ar, J¼15.6 Hz), 6.91 (d,
8H, ]CH, J¼15.9 Hz), 7.09 (br, 4H, Ar), 7.33 (br, 16H, Ar),
7.38 (br, 8H, Ar). 13C NMR (75 MHz, CDCl3) dC (ppm):
14.1 (CH3), 22.6 (CH2), 29.7 (CH2), 31.9 (CH2), 66.8
(C5H4), 69.2 (C5H5), 70.0 (OeCH2), 83.1 (Fcipso), 122.5
(Ar), 122.8 (Ar), 125.6 (Ar), 127.0 (Ar), 127.4 (C]), 131.3
(C]), 131.9 (Aripso), 138.5 (Aripso), 145.5 (Aripso). Electro-
spray (m/z): 5185. Anal. Calcd for C320H320Fe16O8: C, 74.05;
H, 6.17; Fe, 17.28%. Found: C, 74.03; H, 6.19; Fe, 17.30%.
1
1020, 959, 832, 749, 692. H NMR (300 MHz, CDCl3) dH
(ppm): 0.87 (br, 12H, CH3), 1.23 (br, 56H, CH2), 1.68 (s, 8H,
CH2), 2.07 (m, 16H, CH2), 4.76e5.25 (m, 16H, CH2eO),
4.72 (s, 4H, CH), 6.42 (br, 4H, Ar), 7.05 (d, 16H, CH], J¼
16.2 Hz), 7.13 (br, 4H, Ar), 7.14 (d, 16H, CH], J¼16.5 Hz),
7.27e7.61 (m, 104H, Ar). 13C NMR (75 MHz, CDCl3) dC
(ppm): 14.0 (CH3), 22.6 (CH2), 29.3 (CH2), 29.7 (CH2), 31.9
(CH), 70.0 (CH2eO), 112.0 (Ar), 118.0 (Ar), 124.3 (Ar),
126.5 (CH]), 127.5 (Ar), 127.7 (Ar), 128.0 (Ar), 128.6 (Ar),
130.2 (Ar), 136.8 (Aripso), 137.1 (Aripso), 138.1 (Ar), 138.8
(Aripso), 155.3 (AreO). Electrospray (m/z): 3458. Anal. Calcd
for C256H256O8: C, 88.85; H, 7.46. Found: C, 88.85; H, 7.44%.
4.3.4. Dendrimer 16
Yield 0.33 g (92%), brown powder, mp >300 ꢁC, UV CHCl3
(nm): 454, 311, 233. IR (KBr, cmꢀ1): 3368, 3090, 3025, 2894,
1702, 1631, 1591, 1497, 1452, 1408, 1351, 1284, 1246, 1185,
1107, 1048, 1000, 959, 830, 756, 696, 488. 1H NMR
(300 MHz, CDCl3) dH (ppm): 2.47 (br, 8H, CH2), 2.6 (br, 8H,
CH2), 4.13 (br, 16H, CH2eOe), 4.14 (s, 80H, C5H5), 4.47 (s,
4.4. THG Maker-fringe measurements
The nonlinear optical behavior of the synthesized dendrimers
was studied in solid state (solid films) using the guest (mole-
cule)ehost (polymer) approach. Ratios of 70:30 wt % of poly-
styrene (PS) and the dendrimers were dissolved in chloroform.

I. Victorovna-Lijanova et al. / Tetrahedron 64 (2008) 4460e4467
4467
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The entire experiment was computer-controlled.
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In the Maker-fringes technique, the third-harmonic peak
intensity I3u from the substrateefilm structure is compared to
one produced from the substrate alone. Then, the nonlinear
susceptibility c(3) in a film of thickness Lf is determined from:22
9. Samoc, M.; Samoc, A.; Luther-Davies, B.; Humphrey, M. G.; Wong, M. S.
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!
1=2
ꢀ
ꢁ
2 Lc;s
If3u
Is3u
cð3Þ ¼ cðs3Þ
ð1Þ
12. Wang, Y.; Xie, X. B.; Goodson, T., III. Nano Lett. 2005, 5, 2379.
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Chem. B 2000, 104, 179.
p
Lf
where cðs3Þ and Lc,s are the nonlinear susceptibility and co-
herence length, respectively, for the substrate at the fundamental
wavelength. In our calculation we considered csð3Þ
¼
15. West, R.; Wang, Y.; Goodson, T., III. J. Phys. Chem. B 2003, 107,
3419.
3:1 ꢂ 10ꢀ14 esu and Lc,s¼9 mm for the fused silica sub-
strate.20,21 In any case, our samples satisfied the condition
LfꢃLc,s in which the Eq. 1 is valid.
16. Etienne, M.; Biney, A.; Walser, A. D.; Dorsinville, R.; Bauer, D. L. V.;
Balogh-Nair, V. Appl. Phys. Lett. 2005, 87 181913/1.
´
17. Hawker, C. J.; Frechet, J. M. J. J. Am. Chem. Soc. 1990, 112, 7638.
´
18. (a) Garcıa, M. A.; Klimova, E.; Klimova, T.; Flores, P. B.; Romero, A. M.;
´
Acknowledgements
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This work was supported by the DGAPA (IN209106). We
would also like to thank Nieves Z.S.M., Rios O.H., Velasco
Chem. Soc. Jpn. 1998, 71, 2979; (c) Hogberg, A. G. J. Org. Chem.
¨
1980, 45, 4498; (d) Timmerman, P.; Verboon, W.; Reinhoudt, N. D.
Tetrahedron 1996, 52, 2663.
~
~
L., Huerta S.E., Patino M.M.R., and Pena Gonzalez M.A.,
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for technical assistance.
´
´
Garcıa, O.; Olmos-Lopez, M.; Cha, M. Opt. Mater. 2007, 29, 636.
References and notes
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