Synthesis of carrier-transporting dendrimers with perylenebis(dicarboximide)s as a luminescent core

FULL PAPER

DOI: 10.1002/ejoc.200500642

Synthesis of Carrier-Transporting Dendrimers with Perylenebis(dicarboximide)s

as a Luminescent Core

Jianfeng Pan,^[a]Weihong Zhu,*^[a]Shangfeng Li,^[a]Jun Xu,^[a]and He Tian*^[a]

Keywords: Dendrimers / Luminescence / Perylenebis(dicarboximide)s / Synthesis

Well-defined, modular dendrimers enable processing tech-

niques and electronic properties to be tuned independently.

Moreover, the dendritic topology can isolate the core chro-

mophore, thus reducing or eliminating strong intermolecular

interactions. This paper presents the synthesis of three series

of flexible, dendron-functionalized dendrimers as red-light-

emitting materials by a convergent approach: (1) carbazole

(CZ) or oxadiazole (OXZ) terminated imide-type dendrimers,

(2) cascade energy-transferring imide-type dendrimers, and

(3) CZ-terminated perylene bay-type dendrimers. They all

techniques including ¹H and ¹³C NMR spectroscopy and

low/high-resolution mass spectrometry (ESI or MALDI-TOF).

The dendrimers are designed on the basis of the following

considerations: (1) dendron functionalization to incorporate

CZ or OXZ units to realize the carrier-injection adjustment,

(2) tuning or improving solubility, functionality, glass-transi-

tion temperature (T_g) with well-defined dendrons, and (3)

avoiding luminescence quenching with the help of high site-

isolation of dendrons to enhance core luminescence. DSC re-

sults indicate that the incorporation of Fréchet-type poly(aryl

consist of the luminescent core of perylenebis(dicarboximide)s ether) dendrons can improve the amorphous properties and

with specific functional groups of CZ or OXZ at the periphery

and are constructed from flexible Fréchet-type poly(aryl

ether) dendrons. The chemical structures of the dendrons

and dendrimers were determined by standard spectroscopic

increase T_g.

Germany, 2006)

dipole interactions or effective intermolecular π-stacking,

thus becoming either weakly emissive or nonemissive in the

solid state.^[14,15]For a practical application it is necessary

to develop highly promising host-emitting nondoped red

emitters, instead of the above-mentioned red dopant emit-

ters, to overcome the difficult reproducibility of the opti-

mum doping level in devices fabricated by vacuum deposi-

tion.^[6]

Introduction

Organic light-emitting diodes (OLEDs) have received a

huge amount of scientific and industrial attention since

their discovery in 1987 because of their potential applica-

tions in large-area, flat-panel displays.^[1–3]Although much

progress has been made over the past decades,^[4,5]full-color

OLEDs still remain to be improved in terms of efficiency,

color purity, durability, as well as manufacturing process

and cost, which, in turn, rely on the evolution of high per-

formance OLED materials, including RGB emitters. Of the

three primary colors required in a full-color device, green-

light-emitting materials have already been achieved with

high brightness and efficiency, while red- and blue-light-

emitting materials fully meeting the requirements for com-

mercial application are scarce.^[6,7]There are only a few red

dopant emitters, including pyran-containing com-

pounds,^[8,9]europium chelate complexes,^[10–12]and porphy-

rin compounds.^[13]However, all these fluorophores possess

a highly concentration-dependent emission, and have an in-

herent tendency to aggregate due to either attractive dipole–

In this regard, dendrimers^[16]should be a good alterna-

tive to overcome the attractive dipole–dipole interactions or

effective intermolecular π-stacking. Luminescent dendri-

mers consist of three main units: an emissive core, den-

drons, and terminal or peripheral groups. In general, well-

defined dendrimers have good amorphous properties and

high solubility, which makes the fabrication of thin films by

the spin-coating method easier. Such well-defined, modular

construction enables the processing and electronic proper-

ties to be tuned independently. Moreover, the dendritic top-

ology can isolate the core chromophore, thus reducing or

eliminating strong intermolecular interactions.^[17]A number

of dendrimers have been applied in OLEDs.^[18–20]Recently,

a class of rigid polyphenylene dendrimers based on the

chromophore of perylenebis(dicarboximide)s have been

studied by Müllen et al. Those dendrimers show good solu-

bility and film-forming properties, and display strong red-

orange photoluminescence with decreasing chromophore

interactions, although the efficiencies of devices fabricated

[a] Laboratory for Advanced Materials and Institute of Fine

Chemicals, East China University of Science & Technology,

Shanghai 200237, P. R. China

Fax: +86-21-6425-2288

E-mail: tianhe@ecust.edu.cn

whzhu@ecust.edu.cn

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with these materials were still low due to poor charge-trans- constructed by flexible Fréchet-type poly(aryl ether) den-

port through the dendritic shell.^[21,22]

drons. The incorporated CZ or OXZ units can play a major

We have previously reported a class of naphthalenedicar- role in improving both carrier-transport injection and light-

boximide dendrimers exhibiting specific light-harvesting harvesting for the core chromophores. Notably, by taking

and carrier injection-tuning properties,^[23]and herein we ex- advantage of the well-aligned energy level of carbazole–

tend this work to present the synthesis of three series of naphthalenedicarboximide–perylenebis(dicarboximide) flu-

flexible dendron-functionalized dendrimers as red-light- orophores, the naphthalenedicarboximide unit can play a

emitting materials by a convergent approach: (1) carbazole role in cascade energy-transfer from the carbazole to the

(CZ) or oxadiazole (OXZ) terminated imide-type dendri- core perylenebis(dicarboximide) unit. We expect that such

mers, (2) cascade energy-transferring imide-type dendri- a design strategy of using cascade energy-transfer, site-isola-

mers, and (3) CZ-terminated bay-type dendrimers (shown tion, and light-harvesting of the functionalized dendrons

in Schemes 1, 2, and 3, respectively). They are characteristic might conceptually lead to the development of novel prom-

of the luminescent core of perylenebis(dicarboximide)s with ising host-emitting nondoped red emitters based on per-

specific functional groups (CZ or OXZ) at the periphery ylenebis(dicarboximide)s for use in OLEDs.

Scheme 1. Chemical structures of CZ- or OXZ-terminated imide-type dendrimers.

Scheme 2. Chemical structure of cascade energy-transfer imide-type dendrimers.

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Scheme 3. Chemical structures of CZ-terminated bay-type dendrimers.

alkylation of phenolic hydroxy groups, and (2) conversion

of a benzylic alcohol into a benzylic bromide to generate a

reaction focus. In other words, the perylenebis(dicarboxim-

ide) core containing two hydroxy groups and poly(aryl

ether) dendrons bearing CZ or OXZ units were synthesized

separately and then assembled in the last step. The core

chromophore of perylenebis(dicarboximide)s was prepared

in four steps starting from 1,6,7,12-tetrachloro-3,4:9,10-per-

ylenebis(dicarboxylic anhydride).^[29]To increase the solubil-

ity in common organic solvents, phenoxy groups were intro-

duced into the parent structure of the perylenebis(dicarbox-

imide)s.

Facile functional-group manipulation at the periphery al-

lowed the attachment of specific units of carbazoles and

oxadiazoles, which are widely used in OLEDs as hole- and

electron-transporting units, respectively. The convergent as-

sembly of three different generation-dendrons containing

carrier-transporting units is outlined in Schemes 4 and 5.

Treatment of N-(4-bromobutyl)-9H-carbazole or 2-[4-

(bromomethyl)phenyl]-5-(4-tert-butylphenyl)-1,3,4-oxadi-

azole with ethyl 4-hydroxybenzoate in the presence of

K₂CO₃and 18-crown-6 in acetone under argon yielded

(CZ)₁-(G-1)-COOC₂H₅(13) or (OXZ)₁-(G-1)-COOC₂H₅

(14), whose hydrolysis gave the G-1 dendrons (CZ)₁-(G-1)-

COOH (15) or (OXZ)₁-(G-1)-COOH (16). Similarly, com-

pounds 17, 18, 21, and 22 were obtained in good yields

when N-(4-bromobutyl)-9H-carbazole or 2-[4-(bro-

momethyl)phenyl]-5-(4-tert-butylphenyl)-1,3,4-oxadiazole

was treated with methyl 3,5-dihydroxybenzoate or methyl

gallate in acetone at reflux. Subsequent hydrolysis of these

compounds resulted in G-1 dendrons (19, 20, 23, and 24;

Scheme 4). These G-1 dendrons contain one to three car-

rier-transporting units (CZ or OXZ). We used the phenolic

hydroxy groups of the initial benzoate to control the

number of carrier-transporting units introduced onto the

resulting G-1 dendrons.

Results and Discussion

Synthesis of CZ- or OXZ-Terminated Imide-Type

Dendrimers by a Convergent Approach

Dendrimers provide new opportunities for precisely plac-

ing charge-carrier transporting units by generations in a

three-dimensional, nanoscale construction. The dendritic

architecture can also be used to improve the solubility of

luminescent chromophores to form uniform films by the

spin-coating technique, thus overcoming the high cost of

the vacuum-deposition process. In spite of the impressive

control of solubility and amorphous form,^[23,24]the design

of modulating charge-carrier-transporting dendrimers for

OLED applications is so far rare.^[25]In line with our ongo-

ing efforts on studying multi-chromophoric emitters con-

taining a carrier-transporting unit as the EL active layer for

optimized device performance,^[23,26]we designed a series of

novel dendrimers with different generations by a convergent

synthetic approach on the basis of the following considera-

tions: (1) dendron functionalization, (2) incorporating CZ

or OXZ units to tune carrier injection, (3) tuning or im-

proving solubility, functionality, and glass-transition tem-

perature (T_g) with well-defined dendrons, and (4) avoiding

core luminescence quenching with the help of high dendron

site-isolation to enhance the core luminescence.

As shown in Scheme 1, the synthesized imide-type den-

drimers (1–9) contain CZ or OXZ units as specific func-

tional groups at the periphery, Fréchet-type poly(aryl ether)s

as the nonconjugated dendrons, and perylenebis(dicarbox-

imide)s as the chromophore core. Perylenebis(dicarbox-

imide)s are well-known red emitters with high fluorescence

quantum yields and outstanding chemical, thermal, and

photochemical stability, and their derivatives have been

widely applied in organic molecular electronics.^[27]The syn-

thesis of these dendrimers proceeded in a modular fashion

using the convergent approach originally reported by

Hawker and Fréchet.^[28]Two simple synthetic transforma-

tions were used for synthesizing the dendrons: (1) selective

Similarly, the G-2 dendrons 31 and 32 and G-3 dendron

36 can be obtained by repeating the alkylation of the phe-

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Scheme 4. Synthetic route to G-1 dendrons of imide-type dendrimers. Reagents and conditions: a) K₂CO₃, 18-crown-6, acetone, reflux,

60 h; b) KOH, THF/methanol, reflux, 10 h; c) 10% HCl; d) K₂CO₃, 18-crown-6, THF, reflux, 60 h; e) KOH, THF/methanol, reflux, 16 h.

Scheme 5. Synthetic route to G-2 and G-3 dendrons of imide-type dendrimers. Reagents and conditions: a) K₂CO₃, 18-crown-6, acetone,

reflux, 60 h; b) CBr₄/PPh₃, CH₂Cl₂; c) methyl 3,5-dihydroxybenzoate, K₂CO₃, 18-crown-6, THF, reflux, 60 h; d) KOH, THF/methanol,

reflux; e) 10% HCl.

nolic hydroxy groups and transformation of the benzylic temperature proceeded smoothly to afford the correspond-

alcohol into benzylic bromide (shown in Scheme 5). Bromi- ing bromide. In this step, the amount of CBr₄/PPh₃had

nation of the benzylic alcohol group by treatment with car- to be increased with each generation to ensure complete

bon tetrabromide/triphenylphosphane in CH₂Cl₂at room conversion. The dendritic structures of G-2 and G-3 are

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carrier-transporting-unit-terminated with the characteristic chromatography on silica gel and the purity was measured

Fréchet-type poly(aryl ether) dendrons based on the combi- by TLC and HPLC. However, the purification of these den-

nation of 3,5-aryl branching and ethereal connectivity.

As mentioned above, the perylenebis(dicarboximide) core

drimers became more complicated with each generation.

It should be pointed out that we also attempted to pre-

containing two hydroxy groups and the poly(aryl ether) pare the target dendrimers from the reaction between com-

dendrons of benzoic acid bearing CZ or OXZ units were pound 25 and compound 37 by conventional synthetic ester

synthesized separately and then assembled in the last step protocols and methods (Scheme 6). In the first route, a mix-

by esterification. The esterification of a carboxylic acid with ture of compound 25, compound 37, dicyclohexylcarbodi-

an alcohol can be accomplished only if a means is available imide (DCC), and 4-(dimethylamino)pyridine (DMAP) was

to drive the equilibrium towards the ester.^[30]In our synthe- dissolved in anhydrous DMF and stirred at room tempera-

sis, the removal of water by use of a dehydrating agent ture for 48 h. Secondly, we attempted to dehydrate a mix-

proved to be successful for the assembly of dendrons with ture of compounds 25 and 37 in anhydrous DMF, at

a perylenebis(dicarboximide) core. Thus, dehydration with 100 °C, by titration with fresh POCl₃. Finally, the tosylation

dicyclohexylcarbodiimide (DCC) and 4-(dimethylamino)- of compound 25 was attempted as this method has proved

pyridine (DMAP) proceeded in anhydrous CH₂Cl₂at room effective in our synthesis of dendrimers based on 1,8-naph-

temperature with esterification of the core intermediate thalenedicarboximide.^[23]Unfortunately, all these reactions

with the corresponding different generation dendrons to failed to afford the desired compound, probably because of

obtain the target dendrimers. They were purified by the poor solubility of compound 37 in DMF.

Scheme 6. Attempts to synthesize target imide-type dendrimers according to conventional synthetic ester protocols and tosylation.

Scheme 7. Synthetic route to target dendrimer 9. Reagents and conditions: a) DCC, DMAP, CH₂Cl₂, room temp., 24 h.

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G-1 dendrimer 9, with both CZ and OXZ units incorpo- bis(dicarboximide) core, due to the smaller spectral overlap

rated simultaneously from the imide side, was synthesized between the luminescence spectra of the carbazole unit and

similarly. Thus, the core luminescent moiety as well as the the absorption of the perylenebis(dicarboximide) core. This

hole- and electron-transporting units are assembled to- system can be utilized to demonstrate that, with proper

gether in a single molecule of dendrimer 9, which can be chromophore selection, FRET can be more favorable in a

regarded as a bipolar emitter.^[31,32]Dendrimer 9 was ob- vectorial cascade process.

tained by two esterification steps in a poor 0.6% overall

yield (Scheme 7).

The preparation of dendrimer 10 is similar to that de-

scribed above. The convergent assemblies are outlined in

Scheme 8. Treatment of N-(4-bromobutyl)-9H-carbazole

and N-(4-bromobutyl)-4-(piperidin-1-yl)-1,8-naphthalene-

dicarboximide with methyl 3,5-dihydroxybenzoate in the

presence of K₂CO₃and 18-crown-6 in acetone under argon

yielded (CZ)₁-(NP)₁-(G-1)-COOCH₃(39), in 32.9% yield,

and hydrolysis of this compound gave the G-1 dendron

(CZ)₁-(NP)₁-(G-1)-COOH (40). This compound was then

coupled to the core intermediate by dehydration with DCC

and DMAP in anhydrous CH₂Cl₂at room temperature to

afford dendrimer 10.

Synthesis of Cascade Energy-Transferring Imide-Type

Dendrimers

Recently, systems capable of directional Förster reso-

nance energy transfer (FRET) and electron transfer be-

tween several chromophores have received much atten-

tion.^[33]As shown in Scheme 2, another dendrimer (10),

whose dendrons contain carrier-transporting carbazole

units and additional naphthalenedicarboximide units, was

designed and synthesized. Notably, by taking advantage of

the well-aligned energy level of carbazole–naphthalene-

Synthesis of CZ-Terminated Perylene Bay-Type

Dendrimers

dicarboximide–perylenebis(dicarboximide)

fluorophores

the naphthalenedicarboximide unit can play a role in cas-

cade energy-transfer from the carbazole to the core per-

Two notable and unique properties of functionalized

ylenebis(dicarboximide) unit because the absorption peak dendrimers are their light-harvesting and site-isolation ef-

of the naphthalenedicarboximide unit is located between fects. The site-isolation effect can control the intermolecular

that of the carbazole and perylenebis(dicarboximide) units. interactions and reduce or prevent the aggregation of the

A precondition for FRET is the overlap of the donor fluo- core unit, thus alleviating the aggregation problem that is

rescence with the acceptor absorption. Consistent with this, known to be detrimental to device efficiency. To receive a

FRET is favored from the carbazole unit to the naph- better site-isolation effect than that of imide-type dendri-

thalenedicarboximide unit, and then from the naphthalene- mers, we designed another two bay-type dendrimers whose

dicarboximide unit to the perylenebis(dicarboximide) core, dendrons are directly incorporated from the ring of the par-

instead of directly from the carbazole unit to the perylene- ent perylenebis(dicarboximide) (Scheme 3). The synthesis of

Scheme 8. Synthetic route to target dendrimer 10. Reagents and conditions: a) methyl 3,5-dihydroxybenzoate, K₂CO₃, 18-crown-6, THF,

reflux, 60 h; b) KOH, THF/methanol, reflux, 20 h; c) 10% HCl; d) N,NЈ-bis(2-hydroxyethyl)-1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-

perylenebis(dicarboximide), DCC, DMAP, CH₂Cl₂, room temp., 24 h.

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second-generation dendrons containing carbazole units is only two signals are observed for dendron 17, whereas five

outlined in Scheme 9. Treatment of an excess of benzene- different signals in the ratio 8:4:4:2:1 are observed in the

1,4-diol with the appropriate intermediates (molar ratio = case of 35. All integration ratios are exactly proportional to

10:1) in the presence of K₂CO₃and 18-crown-6 in acetone the number of hydrogen atoms. As shown in Figure 2, the

resulted in dendrons 41, 42, and 43. Notably, the synthesis ¹³C NMR spectrum of dendrimer 3 (Scheme 1) shows a

of the third-generation (G-3) bay-type dendrimers was not complicated peak pattern in the range δ = 115–160 ppm due

possible due to the increasing steric hindrance of the sub- to the different environments of the carbon atoms of the

stituents with each generation.

aromatic rings of the dendrimers. The signals labeled 1 and

2 at δ = 166.313 and 163.562 ppm are assigned to carbonyl

carbon atoms in the dendrimer and signals 23/24 and 25/26

are assigned to aliphatic carbon atoms connected to oxygen

and nitrogen atoms, respectively. Finally, the total number

of signals is well consistent with the number of carbon

atoms in the molecule.

Scheme 9. Synthetic route to dendrons 41, 42, and 43 for the bay-

type dendrimers. Reagents and conditions: a) N-(4-bromobutyl)-

9H-carbazole, K₂CO₃, 18-crown-6, acetone, reflux, 36 h; b) 27,

K₂CO₃, 18-crown-6, acetone, reflux, 60 h; c) 34, K₂CO₃, 18-crown-

6, acetone, reflux, 60 h.

Figure 1. ¹H NMR spectra of dendrons 17 (G-1), 29 (G-2), and 35

(G-3).

Structural Characterization

All the dendrimers obtained are well soluble in common

organic solvents such as chlorobenzene, THF, CHCl₃, and

CH₂Cl₂. They are stable during normal manipulation and

no special handling is required. The chemical structures of

the dendrons and dendrimers were determined by standard

spectroscopic techniques, including ¹H and ¹³C NMR spec-

troscopy and low/high-resolution mass spectrometry (ESI

or MALDI-TOF) (see Experimental Section). As an exam-

1

ple, Figure 1 shows the H NMR spectra (500 MHz) of the

Figure 2. ¹³C NMR spectrum of dendrimer 3.

intermediate dendrons 17 (G-1), 29 (G-2), and 35 (G-3) in

CDCl₃. Four characteristic signals of the aromatic hydrogen

Additional definitive evidence was obtained from the

atoms of the carbazole unit are observed at δ Ϸ 7.2– MALDI-TOF mass spectra. All dendrimers show the corre-

8.2 ppm. With increasing generations, the signals assigned sponding molecular ion peaks. For example, the molecular

to the phenyl protons (δ = 6.0–7.0 ppm) of the poly(aryl formula of dendrimer 3 is C₁₃₄H₁₁₀N₆O₁₆. The calculated

ether) dendrons become more complicated. For instance, average for the peak of the molecular ion [M⁺] is 2058 and

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we observed the corresponding [M⁺] peak centered at m/z change in the second heating process. Dendrimer 4 shows a

= 2058.94; the peaks centered at m/z = 2081.95 and 2097.93 slightly higher T_gat 152.7 °C. Thus, the thermal analysis

are ascribed to [M⁺+ Na] and [M⁺+ K], respectively. This results indicate that such dendron-functionalized lumines-

is similar to dendrimer 4, in whose MALDI-TOF mass cent materials have good thermal stability, which is essential

spectrum [M⁺] appears at m/z = 2336.96, with the peaks for for fabricating stable OLEDs.

[M⁺+ Na] and [M⁺+ K] at m/z = 2357.93 and 2373.91,

respectively (see Figure 3). In the MALDI-TOF mass spec-

trum of dendrimer 12 the peaks for [M⁺+ Na] and [M⁺+

K] appear at m/z = 3425.4 and 3438.4, respectively.

Absorption and Fluorescent Properties

These dendrimers show very similar absorption charac-

teristics both in solution and in solid film. In THF, the ab-

sorption peaks at 330 and 345 nm are attributed to the tran-

sition absorption of the carbazole unit, the absorption peak

at around 285 nm is attributed to the oxadiazole unit, and

the latter three peaks to the characteristic absorption of the

perylenebis(dicarboximide) core (Figure 5). Furthermore,

there is a linear increase in the relative absorbance of the

carbazole units (330, 345 nm) in these dendrimers (Fig-

ure 5).^[34]The absorbance of the peripheral CZ or OXZ

units is clearly proportional to their increased number in

each generation, which indirectly reflects the flawless or

perfect structures of the synthesized dendrimers. Notably,

there is no distinct spectral shift of the absorption band of

the peripheral CZ and OXZ units with increasing genera-

tion. The absorption intensity of the perylenebis(dicarboxi-

mide) core in THF does not change notably with increasing

generation but does exhibit a small bathochromic shift,

which is attributed to the micro-environment polarity of the

larger dendritic wedges. Moreover, with respect to the refer-

ence compounds, the absorption spectra of all perylenebis-

(dicarboximide)-core dendrimers are well matched by the

sum of the spectra of the relative constituent chromophores.

In all cases the dendron-functionalized backbone does not

appear to significantly perturb the electronic transition in

the ground state. This provides a window to selectively ex-

cite the dendron and the core to study the photoinduced

energy and electron transfers.

Figure 3. MALDI-TOF mass spectra of dendrimers 3 (top) and 4

(bottom).

Thermal Stability

Dendrimers are generally able to prevent spatial reorien-

tation of molecules, thus eliminating their tendency to

recrystallize and favorably increasing their glass-transition

temperature (T_g). In our dendrimers, compounds 3 and 4

(G-1) have a higher melting point than the other dendri-

mers. For instance, the curve of the DSC thermogram for

dendrimer 3 (Figure 4) reveals that T_gis at 110.2 °C in the

heating process. When the compound was cooled at a rate

of 10 °Cmin^–1from 260 to 30 °C no distinct crystallization

phase was observed. Broad exothermic peaks due to

crystallization were observed at around 162 and 192 °C for

the first and second heating, respectively, and T_gdid not

Figure 5. Normalized absorption spectra of dendrimers 1, 3, 5, and

7 in THF (2.0×10^–5). Inset: Plot of number of carbazole units

in dendrimer vs. absorbance at 345 nm.

All synthesized dendrimers 1–12 in THF show character-

Figure 4. DSC trace of dendrimer 3.

istic luminescence of the core perylenebis(dicarboximide)

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(peak at around 600 nm). Compared with their fluorescence generate a reaction focus. Esterification of the core interme-

in THF, the fluorescence of the dendrimers in the solid state diate with the corresponding different generation dendrons

is red-shifted; for example, the red-shifts of dendrimers 1, promoted by dehydration with dicyclohexylcarbodiimide

3, and 5 are 72, 60, and 51 nm, respectively (see Figure 6). (DCC) and 4-(dimethylamino)pyridine (DMAP) was easily

These results indicate that a higher-generation dendrimer achieved in anhydrous CH₂Cl₂at room temperature to ob-

has a relatively smaller Stokes shift than a lower-generation tain the target dendrimers. All dendrimers have good solu-

one, which is indicative of a certain degree of site isolation bility and thermal stability, and could be applied as promis-

or dendron dilution, which reduces or prevents the aggrega- ing active red luminescent emitters with carrier-transport

tion of the core.

ability in OLEDs.

Experimental Section

General Information: Commercially available reagents were used

without further purification unless noted otherwise. Solvents were

purified by common methods. The starting materials 2-[4-(bro-

momethyl)phenyl]-5-(4-tert-butylphenyl)-1,3,4-oxadiazole,^[35]N-(4-

bromobutyl)-9H-carbazole,^[36]and N-(4-bromobutyl)-4-(piperidin-

1-yl)-1,8-naphthalenedicarboximide^[37]were prepared according to

literature procedures. Melting points were measured with an X4

1

micro-melting point apparatus. H and ¹³C NMR spectra were re-

corded with a Bruker AM-500 spectrometer. Mass spectra were

recorded using the ESI or MALDI-TOF techniques with α-cyano-

4-hydroxycinnamic acid as matrix. HPLC was carried out with an

Agilent 1100 LC system. Glass-transition temperatures (T_g) were

measured with a differential scanning calorimeter (TA DSC 2910)

at a scan rate of 10 °Cmin^–1. Absorption and fluorescence spectra

were recorded with a Varian Cary 500 and a Varian Cary Eclipse

spectrometer, respectively.

Figure 6. Normalized fluorescence spectra of dendrimers 1, 3, and

5 in solid film excited at 460 nm.

The interactions between the peripheral units and the

perylenebis(dicarboximide) core in the dendrimers were

also studied by steady-state and time-resolved fluorescence

spectroscopy under both direct and indirect excitation. Be-

cause perylenebis(dicarboximide) derivatives have a high

electron affinity [3.9 eV for the LUMO energy of the core

perylenebis(dicarboximide)],^[27b]photo-induced electron

transfer (PIET) occurs from the low-oxidation-potential

units of the carbazole to the perylenebis(dicarboximide)

core. Preliminary results show that two different phenome-

nona exist: no enhanced core fluorescence for dendrimers

bearing carbazole units is observed because the energy

transfer or light-harvesting of the peripheral carbazole is

counteracted by PIET, while enhanced core fluorescence

arising from the energy transfer or light-harvesting of pe-

ripheral oxadiazole is observed for dendrimers bearing

these units as no PIET can take place because of the high

electron affinity of the oxadiazole and perylenebis(dicar-

boximide). Further studies of photoinduced energy and

electron transfers and EL device performances are now un-

derway, and will be reported elsewhere.

Ethyl 4-[4-(9H-Carbazol-9-yl)butoxy]benzoate [(CZ)₁-(G-1)-CO-

OC₂H₅, 13]: A mixture of 9-(4-bromobutyl)-9H-carbazole (1.0 g,

3.3 mmol), ethyl 4-hydroxybenzoate (0.6 g, 3.6 mmol), anhydrous

potassium carbonate (1.2 g, 8.7 mmol), and 18-crown-6 (0.4 g,

1.4 mmol) in anhydrous acetone (50 mL) was refluxed with vigor-

ous stirring under argon for 60 h. After cooling to room tempera-

ture, the mixture was concentrated to dryness under reduced pres-

sure. The residue was partitioned between CH₂Cl₂and H₂O and

the aqueous layer was extracted with CH₂Cl₂(3×30 mL). The

combined organic layers were dried with anhydrous MgSO₄and

the solvents evaporated. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂/CCl₄(2:1) to give

1

13 as a white solid (1.1 g, yield 85.9%). M.p. 84–85 °C. H NMR

(500 MHz, CDCl₃, 25 °C): δ = 1.45 (t, J = 7.2 Hz, 3 H, -CH₃), 1.88

(m, 2 H, -CH₂-), 2.10 (m, 2 H, -CH₂-), 3.95 (t, J = 6.1 Hz, 2 H,

-OCH₂-), 4.36 (m, 2 H, -OCH₂-), 4.40 (t, J = 7.0 Hz, 2 H,

-NCH₂-), 6.82 (d, J = 8.9 Hz, 2 H, Ph-H), 7.20 [t, J = 7.0 Hz, 2 H,

Ph-H (CZ)], 7.40–7.50 [td, J = 7.6, J = 8.0 Hz, 4 H, Ph-H (CZ)],

7.95 (d, J = 8.7 Hz, 2 H, Ph-H), 8.12 [d, J = 7.6 Hz, 2 H, Ph-H

(CZ)] ppm.

(OXZ)₁-(G-1)-COOC₂H₅(14): A mixture of 2-[4-(bromomethyl)-

phenyl]-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (1.5 g, 4.0 mmol),

ethyl 4-hydroxybenzoate (0.8 g, 4.8 mmol), anhydrous potassium

carbonate (1.6 g, 11.6 mmol), and 18-crown-6 (0.4 g, 1.4 mmol) in

anhydrous acetone (50 mL) was refluxed with vigorous stirring un-

der argon for 60 h. After cooling to room temperature, the mixture

was concentrated to dryness under reduced pressure. The residue

was partitioned between CH₂Cl₂and H₂O and the aqueous layer

was extracted with CH₂Cl₂(3×30 mL). The combined organic lay-

ers were dried with anhydrous MgSO₄and the solvents evaporated.

The product was purified by column chromatography on silica gel

Conclusions

Different generations of three novel series of dendrimers

for red-light emission that contain perylenebis(dicarbox-

imide) cores, Fréchet-type poly(aryl ether) dendrons, and

peripheral functional units such as carbazole or oxadiazole

have been designed and synthesized. Two simple synthetic

transformations have been used to synthesize the dendrons,

namely selective alkylation of phenolic hydroxy groups and

eluting with CH₂Cl₂/CCl₄(4:1) to give 14 as a white solid (1.6 g,

1

conversion of a benzylic alcohol into a benzylic bromide to yield 87.0%). M.p. 76–77 °C. H NMR (500 MHz, CDCl₃, 25 °C):

994

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Carrier-Transporting Dendrimers with a Luminescent Core

FULL PAPER

δ = 1.38 (m, 12 H, -CH₃), 4.30 (m, 2 H, -OCH₂-), 5.23 (s, 2 H, chromatography on silica gel eluting with CH₂Cl₂/CCl₄(4:1) to give

-OCH₂-), 7.07 (d, J = 8.7 Hz, 2 H, Ph-H), 7.58 [t, J = 8.4 Hz, 4 H, 18 as a white solid (5.2 g, yield 85.6%). M.p. 124–125 °C. ¹H NMR

Ph-H (OXZ)], 7.96 (d, J = 8.8 Hz, 2 H, Ph-H), 8.01 [d, J = 8.7 Hz,

2 H, Ph-H (OXZ)], 8.10 [d, J = 8.3 Hz, 2 H, Ph-H (OXZ)] ppm.

(500 MHz, CDCl₃, 25 °C): δ = 1.37 (s, 18 H, -CH₃), 3.90 (s, 3 H,

-OCH₃), 5.20 (s, 4 H, -OCH₂-), 6.77 (s, 1 H, Ph-H), 7.30 (s, 2 H,

Ph-H), 7.52–7.68 [dd, J = 8.0, J = 8.3 Hz, 8 H, Ph-H (OXZ)], 8.05

[d, J = 8.2 Hz, 4 H, Ph-H (OXZ)], 8.20 [d, J = 8.0 Hz, 4 H, Ph-H

(OXZ)] ppm.

4-[4-(9H-Carbazol-9-yl)butoxy]benzoic Acid [(CZ)₁-(G-1)-COOH,

15]: A mixture of compound 13 (1.1 g, 2.8 mmol) and KOH (3.8 g,

67.2 mmol) in tetrahydrofuran/methanol (15 mL/30 mL) was re-

fluxed with vigorous stirring for 10 h. After cooling to room tem-

perature, the mixture was concentrated to dryness under reduced

pressure. The residue was acidified with 10% aqueous HCl solution

(300 mL), then the precipitate was filtered and washed with ethanol

to give 15 as a white solid (1.0 g, yield 98.1%). The product was

used directly in the next reaction without further purification. M.p.

178–180 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.87 (m, 2

3,5-Bis[4-(9H-carbazol-9-yl)butoxy]benzoic Acid [(CZ)₂-(G-1)-

COOH, 19]: A mixture of compound 17 (4.1 g, 6.7 mmol) and

KOH (3.8 g, 67.2 mmol) in tetrahydrofuran/methanol (30 mL/

60 mL) was refluxed with vigorous stirring for 10 h. After cooling

to room temperature, the mixture was concentrated to dryness un-

der reduced pressure and the residue was acidified with 10% aque-

ous HCl solution (400 mL). The precipitate was filtered off and

H, -CH₂-), 2.10 (m, 2 H, -CH₂-), 3.90 (t, J = 6.1 Hz, 2 H, washed with ethanol to give 19 as a white solid (3.8 g, yield 95.9%).

-OCH₂-), 4.40 (t, J = 7.1 Hz, 2 H, -NCH₂-), 6.82 (d, J = 8.8 Hz, 2

H, Ph-H), 7.20 [t, J = 7.1 Hz, 2 H, Ph-H (CZ)], 7.40–7.50 [m, 4 H,

Ph-H (CZ)], 7.95 (d, J = 8.6 Hz, 2 H, Ph-H), 8.11 [d, J = 7.5 Hz,

2 H, Ph-H (CZ)] ppm.

The product was used directly in the next reaction without further

purification. M.p. 179–181 °C. ¹H NMR (500 MHz, CDCl₃,

25 °C): δ = 1.72 (m, 4 H, -CH₂-), 2.10 (m, 4 H, -CH₂-), 3.90 (t, J

= 6.0 Hz, 4 H, -OCH₂-), 4.40 (t, J = 7.0 Hz, 4 H, -NCH₂-), 6.54

(s, 1 H, Ph-H), 7.17 (s, 2 H, Ph-H), 7.22 [t, J = 6.9 Hz, 4 H, Ph-H

(CZ)], 7.38–7.50 [m, 8 H, Ph-H (CZ)], 8.10 [d, J = 7.4 Hz, 4 H,

Ph-H (CZ)] ppm.

(OXZ)₁-(G-1)-COOH (16): A mixture of compound 14 (1.6 g,

3.5 mmol) and KOH (2.5 g, 44.6 mmol) in tetrahydrofuran/meth-

anol (30 mL/15 mL) was refluxed with vigorous stirring for 10 h.

After cooling to room temperature, the mixture was concentrated

to dryness under reduced pressure and the residue was acidified

with 10% aqueous HCl solution (300 mL). The precipitate was fil-

tered off and washed with ethanol to give 16 as a white solid (1.4 g,

yield 93.4%). The product was used directly in the next reaction

without further purification. M.p. 158–160 °C. ¹H NMR

(OXZ)₂-(G-1)-COOH (20): A mixture of compound 18 (5.0 g,

6.7 mmol) and KOH (4.0 g, 71.4 mmol) in tetrahydrofuran/meth-

anol (80 mL/40 mL) was refluxed with vigorous stirring for 10 h.

After cooling to room temperature, the mixture was concentrated

to dryness under reduced pressure and the residue was acidified

with 10% aqueous HCl solution (400 mL). The precipitate was fil-

(500 MHz, CDCl₃, 25 °C): δ = 1.38 (s, 9 H, -CH₃), 5.25 (s, 2 H, tered off and washed with ethanol to give 20 as a white solid (4.4 g,

-OCH₂-), 7.07 (d, J = 8.6 Hz, 2 H, Ph-H), 7.58 [m, 4 H, Ph-H

(OXZ)], 7.96–8.02 [m, 4 H, Ph-H, Ph-H (OXZ)], 8.12 [d, J =

7.5 Hz, 2 H, Ph-H (OXZ)] ppm.

yield 89.2%). The product was used directly in the next reaction

without further purification. M.p. 138–140 °C. ¹H NMR

(500 MHz, CDCl₃, 25 °C): δ = 1.38 (s, 18 H, -CH₃), 5.19 (s, 4 H,

CH₂-), 6.89 (s, 1 H, Ph-H), 7.39 (s, 2 H, Ph-H), 7.54–7.63 [dd, J =

8.0, J = 8.3 Hz, 8 H, Ph-H (OXZ)], 8.05 [d, J = 8.2 Hz, 4 H, Ph-

H (OXZ)], 8.18 [d, J = 7.9 Hz, 4 H, Ph-H (OXZ)] ppm.

Methyl 3,5-Bis[4-(9H-carbazol-9-yl)butoxy]benzoate [(CZ)₂-(G-1)-

COOCH₃, 17]:

A mixture of N-(4-bromobutyl)-9H-carbazole

(5.0 g, 16.5 mmol), methyl 3,5-dihydroxybenzoate (1.2 g,

7.1 mmol), anhydrous potassium carbonate (5.9 g, 42.8 mmol), and

18-crown-6 (0.8 g, 2.8 mmol) in anhydrous acetone (50 mL) was

refluxed with vigorous stirring under argon for 60 h. After cooling

to room temperature, the mixture was concentrated to dryness un-

der reduced pressure. The residue was then partitioned between

CH₂Cl₂and H₂O and the aqueous layer was extracted with CH₂Cl₂

(3×40 mL). The combined organic layers were dried with anhy-

drous MgSO₄and the solvents evaporated. The product was puri-

fied by column chromatography on silica gel eluting with CH₂Cl₂/

CCl₄(2:1) to give 17 as a white solid (4.1 g, yield 94.2%). M.p.

140–142 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.87 (m, 4

Methyl 3,4,5-Tris[4-(9H-carbazol-9-yl)-butoxy]benzoate [(CZ)₃-(G-

1)-COOCH₃, 21]: A mixture of N-(4-bromobutyl)-9H-carbazole

(3.8 g, 12.6 mmol), methyl gallate (0.6 g, 3.3 mmol), anhydrous po-

tassium carbonate (3.0 g, 21.7 mmol), and 18-crown-6 (0.4 g,

1.4 mmol) in anhydrous THF (50 mL) was refluxed with vigorous

stirring under argon for 60 h. After cooling to room temperature,

the mixture was concentrated to dryness under reduced pressure

and the residue was partitioned between CH₂Cl₂and H₂O. The

aqueous layer was extracted with CH₂Cl₂(3×40 mL), the com-

bined organic layers were dried with anhydrous MgSO₄, and the

solvents evaporated. The product was purified by column

H, -CH₂-), 2.08 (m, 4 H, -CH₂-), 3.88 (s, 3 H, -OCH₃), 3.95 (t, J chromatography on silica gel eluting with CH₂Cl₂/CCl₄(2:1) to give

1

= 6.0 Hz, 4 H, -OCH₂-), 4.40 (t, J = 7.0 Hz, 4 H, -NCH₂-), 6.54

(s, 1 H, Ph-H), 7.13 (s, 2 H, Ph-H), 7.20 [t, J = 7.4 Hz, 4 H, Ph-H

(CZ)], 7.40–7.50 [td, J = 7.7, J = 8.1 Hz, 8 H, Ph-H (CZ)], 8.12 [d,

J = 7.8 Hz, 4 H, Ph-H (CZ)] ppm.

21 as a white solid (2.5 g, yield 89.4%). M.p. 89–91 °C. H NMR

(500 MHz, CDCl₃, 25 °C): δ = 1.67 (m, 2 H, -CH₂-), 1.72 (m, 4

H, -CH₂-), 1.97 (m, 6 H, -CH₂-), 3.86 (m, 5 H, -OCH₂-, -OCH₃),

3.92 (t, J = 6.1 Hz, 4 H, -OCH₂-), 4.12 (t, J = 7.3 Hz, 2 H,

-NCH₂-), 4.22 (t, J = 7.0 Hz, 4 H, -NCH₂-), 7.22 [m, 8 H, Ph-H,

Ph-H (CZ)], 7.25 [t, J = 7.4 Hz, 2 H, Ph-H (CZ)], 7.28 [d, J =

8.2 Hz, 4 H, Ph-H (CZ)], 7.38 [m, 6 H, Ph-H (CZ)], 8.10 [m, 6 H,

Ph-H (CZ)] ppm.

(OXZ)₂-(G-1)-COOCH₃(18): A mixture of 2-[4-(bromomethyl)-

phenyl]-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (6.6 g, 17.7 mmol),

methyl 3,5-dihydroxybenzoate (1.36 g, 8.1 mmol), anhydrous potas-

sium carbonate (5.0 g, 36.2 mmol), and 18-crown-6 (0.8 g,

2.8 mmol) in anhydrous acetone (50 mL) was refluxed with vigor-

ous stirring under argon for 60 h. After cooling to room tempera-

ture, the mixture was concentrated to dryness under reduced pres-

sure. The residue was partitioned between CH₂Cl₂and H₂O and

the aqueous layer was extracted with CH₂Cl₂(3×40 mL). The

combined organic layers were dried with anhydrous MgSO₄and

the solvents evaporated. The product was purified by column

(OXZ)₃-(G-1)-COOCH₃(22): A mixture of 2-[4-(bromomethyl)-

phenyl]-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (2.9 g, 7.8 mmol),

methyl gallate (0.45 g, 2.4 mmol), anhydrous potassium carbonate

(2.0 g, 14.5 mmol), and 18-crown-6 (0.4 g, 1.4 mmol) in anhydrous

THF (60 mL) was refluxed with vigorous stirring under argon for

60 h. After cooling to room temperature, the mixture was concen-

trated to dryness under reduced pressure, the residue was parti-

Eur. J. Org. Chem. 2006, 986–1001

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995

J. Pan, W. Zhu, S. Li, J. Xu, H. Tian

FULL PAPER

tioned between CH₂Cl₂and H₂O, and the aqueous layer was ex-

tracted with CH₂Cl₂(3×40 mL). The combined organic layers were

dried with anhydrous MgSO₄and the solvents evaporated. The

product was purified by column chromatography on silica gel elut-

ing with CH₂Cl₂/CCl₄(4:1) to give 22 as a white solid (1.2 g, yield

(OXZ)₂-(G-1)-CH₂OH (26): A mixture of 2-[4-(bromomethyl)

phenyl]-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (5.4 g, 14.5 mmol),

3,5-dihydroxybenzyl alcohol (1.0 g, 7.1 mmol), anhydrous potas-

sium carbonate (3.4 g, 24.6 mmol), and 18-crown-6 (0.4 g,

1.4 mmol) in anhydrous acetone (50 mL) was refluxed with vigor-

46.5%). M.p. 174–175 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ ous stirring under argon for 60 h. After cooling to room tempera-

= 1.33 (s, 9 H, -CH₃), 1.38 (s, 18 H, -CH₃), 3.90 (s, 3 H, -OCH₃), ture, the mixture was concentrated to dryness under reduced pres-

5.25 (s, 6 H, -OCH₂-), 7.43 (s, 2 H, Ph-H), 7.52 [d, J = 8.5 Hz, 2

H, Ph-H (OXZ)], 7.56 [d, J = 8.5 Hz, 4 H, Ph-H (OXZ)], 7.60 [t,

J = 8.5 Hz, 6 H, Ph-H (OXZ)], 8.01 [d, J = 8.4 Hz, 2 H, Ph-H

(OXZ)], 8.06 [d, J = 8.5 Hz, 6 H, Ph-H (OXZ)], 8.16 [d, J = 8.3 Hz,

4 H, Ph-H (OXZ)] ppm.

sure. The residue was partitioned between CH₂Cl₂and H₂O, and

the aqueous layer was extracted with CH₂Cl₂(3×40 mL). The

combined organic layers were dried with anhydrous MgSO₄and

the solvents evaporated. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂/CH₃COCH₃

(5:1) to give 26 as a white solid (4.2 g, yield 82.4%). M.p. 106–

108 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.37 (s, 18 H,

-CH₃), 4.70 (s, 2 H, -CH₂OH), 5.20 (s, 4 H, -OCH₂-), 6.57 (s, 1 H,

Ph-H), 6.78 (s, 2 H, Ph-H), 7.50 [d, J = 8.1 Hz, 4 H, Ph-H (OXZ)],

7.55 [d, J = 7.8 Hz, 4 H, Ph-H (OXZ)], 8.05 [d, J = 8.0 Hz, 4 H,

Ph-H (OXZ)], 8.15 [d, J = 7.8 Hz, 4 H, Ph-H (OXZ)] ppm.

3,4,5-Tris[4-(9H-carbazol-9-yl)butoxy]benzoic Acid [(CZ)₃-(G-1)-

COOH, 23]: A mixture of compound 21 (2.3 g, 2.7 mmol) and

KOH (4.0 g, 71.4 mmol) in tetrahydrofuran/methanol (20 mL/

40 mL) was refluxed with vigorous stirring for 16 h. After cooling

to room temperature, the mixture was concentrated to dryness un-

der reduced pressure and the residue was acidified with 10% aque-

ous HCl solution (400 mL). The precipitate was filtered off and

washed with ethanol to give 23 as a white solid (2.1 g, yield 94.7%).

The product was used directly in the next reaction without further

(CZ)₂-(G-1)-CH₂Br (27): Triphenylphosphane (0.4 g, 1.5 mmol)

was slowly added to a mixture of compound 25 (1.0 g, 1.72 mmol)

and carbon tetrabromide (0.44 g, 1.25 mmol) in the minimum

amount of anhydrous CH₂Cl₂required to dissolve these reagents.

1

purification. M.p. 85–86 °C. H NMR (500 MHz, CDCl₃, 25 °C):

δ = 1.58 (m, 2 H, -CH₂-), 1.76 (m, 4 H, -CH₂-), 1.97 (m, 6 H, After stirring under argon for 20 min, further carbon tetrabromide

-CH₂-), 3.88 (t, J = 6.0 Hz, 2 H, -OCH₂-), 3.92 (t, J = 6.0 Hz, 4 and triphenylphosphane were added in 1.25-equiv. amounts at 10-

H, -OCH₂-), 4.13 (t, J = 7.2 Hz, 2 H, -NCH₂-), 4.22 (t, J = 7.0 Hz,

4 H, -NCH₂-), 7.20 [m, 8 H, Ph-H, Ph-H (CZ)], 7.23 [m, 2 H, Ph-

H (CZ)], 7.29 [d, J = 8.1 Hz, 4 H, Ph-H (CZ)], 7.39 [m, 6 H, Ph-

min intervals until TLC showed no starting benzyl alcohol any-

more. The reaction mixture was then poured into water and ex-

tracted with CH₂Cl₂(3×20 mL), and the combined extracts were

H (CZ)], 8.08 [m, 6 H, Ph-H (CZ)] ppm. MS (ESI): m/z = 856.4 dried with MgSO₄and the solvents evaporated. The product was

[M⁺+ Na].

purified by column chromatography on silica gel eluting with

CH₂Cl₂to give 27 as a pale-yellow solid (1.02 g, yield 92.1%). M.p.

163–164 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.80 (m, 4

H, -CH₂-), 2.10 (m, 4 H, -CH₂-), 3.85 (t, J = 6.1 Hz, 4 H,

-OCH₂-), 4.20 (s, 2 H, -CH₂Br), 4.37 (t, J = 7.1 Hz, 4 H,

-NCH₂-), 6.30 (s, 1 H, Ph-H), 6.45 (s, 2 H, Ph-H), 7.20 [t, J =

7.3 Hz, 4 H, Ph-H (CZ)], 7.40–7.50 [td, J = 7.8, J = 8.0 Hz, 8 H,

Ph-H (CZ)], 8.20 [d, J = 7.8 Hz, 4 H, Ph-H (CZ)] ppm.

(OXZ)₃-(G-1)-COOH (24): A mixture of compound 22 (1.2 g,

1.1 mmol) and KOH (1.0 g, 17.9 mmol) in tetrahydrofuran/meth-

anol (40 mL/20 mL) was refluxed with vigorous stirring for 16 h.

After cooling to room temperature, the mixture was concentrated

to dryness under reduced pressure and the residue was acidified

with 10% aqueous HCl solution (150 mL). The precipitate was fil-

tered off and washed with ethanol to give 24 as a white solid (1.1 g,

yield 93.0%). The product was used directly in the next reaction

without further purification. M.p. 149–151 °C. ¹H NMR

(OXZ)₂-(G-1)-CH₂Br (28): Triphenylphosphane (0.4 g, 1.5 mmol)

was slowly added to a mixture of compound 26 (0.65 g, 0.90 mmol)

(500 MHz, CDCl₃, 25 °C): δ = 1.32 (s, 9 H, -CH₃), 1.38 (s, 18 H, and carbon tetrabromide (0.44 g, 1.25 mmol) in the minimum

-CH₃), 5.25 (s, 6 H, -OCH₂-), 7.43–7.56 [m, 8 H, Ph-H, Ph-H

(OXZ)], 7.60 [t, J = 7.5 Hz, 6 H, Ph-H (OXZ)], 8.01–8.06 [m, 8 H,

Ph-H (OXZ)], 8.16 [d, J = 7.8 Hz, 4 H, Ph-H (OXZ)] ppm. MS

(ESI): m/z = 1041.4 [M⁺].

amount of anhydrous CH₂Cl₂required to dissolve these reagents.

After stirring under argon for 20 min, further carbon tetrabromide

and triphenylphosphane were added in 1.25-equiv. amounts at 10-

min intervals until TLC showed no starting benzyl alcohol any-

more. The reaction mixture was then poured into water and ex-

tracted with CH₂Cl₂(3×20 mL), the combined extracts were dried

with MgSO₄, and the solvents evaporated. The product was puri-

fied by column chromatography on silica gel eluting with CH₂Cl₂/

CH₃COCH₃(10:1) to give 28 as a pale-yellow solid (0.29 g, yield

3,5-Bis{[4-(9H-carbazol-9-yl)butoxy]phenyl}methanol [(CZ)₂-(G-1)-

CH₂OH, 25]: A mixture of N-(4-bromobutyl)-9H-carbazole (4.4 g,

14.5 mmol), 3,5-dihydroxybenzyl alcohol (1.0 g, 7.1 mmol), anhy-

drous potassium carbonate (3.4 g, 24.6 mmol), and 18-crown-6

(0.8 g, 2.8 mmol) in anhydrous acetone (50 mL) was refluxed with

vigorous stirring under argon for 60 h. After cooling to room tem-

perature, the mixture was concentrated to dryness under reduced

pressure. The residue was partitioned between CH₂Cl₂and H₂O

and the aqueous layer was extracted with CH₂Cl₂(3×40 mL). The

combined organic layers were dried with anhydrous MgSO₄and

the solvents evaporated. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂to give 25 as a

white solid (3.44 g, yield 82.8%). M.p. 118–120 °C. ¹H NMR

1

41.3%). M.p. 97–98 °C. H NMR (500 MHz, CDCl₃, 25 °C): δ =

1.38 (s, 18 H, -CH₃), 4.43 (s, 2 H, -CH₂Br), 5.14 (s, 4 H, -OCH₂-),

6.57 (s, 1 H, Ph-H), 6.68 (s, 2 H, Ph-H), 7.56 [d, J = 8.2 Hz, 4 H,

Ph-H (OXZ)], 7.59 [d, J = 8.0 Hz, 4 H, Ph-H (OXZ)], 8.07 [d, J =

8.2 Hz, 4 H, Ph-H (OXZ)], 8.17 [d, J = 8.0 Hz, 4 H, Ph-H (OXZ)]

ppm.

(CZ)₄-(G-2)-COOCH₃(29): A mixture of compound 27 (1.4 g,

2.2 mmol), methyl 3,5-dihydroxybenzoate (0.17 g, 1.0 mmol), anhy-

(500 MHz, CDCl₃, 25 °C): δ = 1.80 (m, 4 H, -CH₂-), 2.10 (m, 4 drous potassium carbonate (1.2 g, 8.7 mmol), and 18-crown-6

H, -CH₂-), 3.85 (t, J = 6.1 Hz, 4 H, -OCH₂-), 4.37 (t, J = 7.1 Hz,

4 H, -NCH₂-), 4.70 (s, 2 H, -CH₂OH), 6.25 (s, 1 H, Ph-H), 6.50 (s,

2 H, Ph-H), 7.20 [t, J = 6.8 Hz, 4 H, Ph-H (CZ)], 7.40–7.50 [td, J

= 7.9, J = 8.0 Hz, 8 H, Ph-H (CZ)], 8.20 [d, J = 7.8 Hz, 4 H, Ph-

H (CZ)] ppm.

(0.4 g, 1.4 mmol) in anhydrous THF (50 mL) was refluxed with vig-

orous stirring under argon for 60 h. After cooling to room tempera-

ture, the mixture was concentrated to dryness under reduced pres-

sure, the residue was partitioned between CH₂Cl₂and H₂O, and

the aqueous layer was extracted with CH₂Cl₂(3×30 mL). The

996

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Eur. J. Org. Chem. 2006, 986–1001

Carrier-Transporting Dendrimers with a Luminescent Core

FULL PAPER

combined organic layers were dried with anhydrous MgSO₄and

the solvents evaporated. The product was purified by column

(0.38 g, 1.4 mmol) in anhydrous acetone (50 mL) was refluxed with

vigorous stirring under argon for 60 h. After cooling to room tem-

perature, the mixture was concentrated to dryness under reduced

chromatography on silica gel eluting with CH₂Cl₂/CCl₄(2:1) to give

1

29 as a white solid (1.2 g, yield 92.6%). M.p. 75–77 °C. H NMR pressure, the residue was partitioned between CH₂Cl₂and H₂O,

(500 MHz, CDCl₃, 25 °C): δ = 1.80 (m, 8 H, -CH₂-), 2.04 (m, 8 and the aqueous layer was extracted with CH₂Cl₂(3×40 mL). The

H, -CH₂-), 3.86 (s, 3 H, -OCH₃), 3.88 (m, 8 H, -OCH₂-), 4.35 (t, J

combined organic layers were dried with anhydrous MgSO₄and

= 6.7 Hz, 8 H, -NCH₂-), 4.90 (s, 4 H, -OCH₂-), 6.30 (s, 2 H, Ph- the solvents evaporated. The product was purified by column

H), 6.50 (s, 4 H, Ph-H), 6.75 (s, 1 H, Ph-H), 7.20 [t, J = 7.1 Hz, 8

chromatography on silica gel eluting with CH₂Cl₂to give 33 as a

H, Ph-H (CZ)], 7.25 (s, 2 H, Ph-H), 7.30–7.50 [td, J = 7.5, J = white solid (7.1 g, yield 79.2%). M.p. 96–98 °C. ¹H NMR

7.9 Hz, 16 H, Ph-H (CZ)], 8.10 [d, J = 7.6 Hz, 8 H, Ph-H (CZ)] (500 MHz, CDCl₃, 25 °C): δ = 1.80 (m, 8 H, -CH₂-), 2.05 (m, 8

ppm.

H, -CH₂-), 3.85 (t, J = 6.1 Hz, 8 H, -OCH₂-), 4.37 (t, J = 7.0 Hz,

8 H, -NCH₂-), 4.62 (s, 2 H, -CH₂OH), 4.90 (s, 4 H, -OCH₂-), 6.25

(s, 2 H, Ph-H), 6.42 (s, 5 H, Ph-H), 6.50 (s, 2 H, Ph-H), 7.20 [t, J

= 7.8 Hz, 8 H, Ph-H (CZ)], 7.40 [d, J = 7.9 Hz, 8 H, Ph-H (CZ)],

7.48 [t, J = 7.9 Hz, 8 H, Ph-H (CZ)], 8.20 [d, J = 7.7 Hz, 8 H, Ph-

H (CZ)] ppm.

(OXZ)₄-(G-2)-COOCH₃(30): A mixture of compound 28 (2.0 g,

2.6 mmol), methyl 3,5-dihydroxybenzoate (0.195 g, 1.2 mmol), an-

hydrous potassium carbonate (1.2 g, 8.7 mmol), and 18-crown-6

(0.4 g, 1.4 mmol) in anhydrous THF (50 mL) was refluxed with vig-

orous stirring under argon for 60 h. After cooling to room tempera-

ture, the mixture was concentrated to dryness under reduced pres-

sure. The residue was partitioned between CH₂Cl₂and H₂O, and

the aqueous layer was extracted with CH₂Cl₂(3×30 mL). The

combined organic layers were dried with anhydrous MgSO₄and

the solvents evaporated. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂/CH₃COCH₃

(10:1) to give 30 as a white solid (1.0 g, yield 54.8%). M.p. 111–

113 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.37 (s, 36 H,

-CH₃), 3.89 (s, 3 H, -OCH₃), 5.04 (s, 4 H, -OCH₂-), 5.14 (s, 8 H,

-OCH₂-), 6.59 (s, 2 H, Ph-H), 6.70 (s, 4 H, Ph-H), 6.75 (s, 1 H, Ph-

H), 7.20 (s, 2 H, Ph-H), 7.56 [m, 16 H, Ph-H (OXZ)], 8.05 [d, J =

8.2 Hz, 8 H, Ph-H (OXZ)], 8.14 [d, J = 8.1 Hz, 8 H, Ph-H (OXZ)]

ppm.

(CZ)₄-(G-2)-CH₂Br (34): Triphenylphosphane (1.2 g, 4.5 mmol)

was slowly added to a mixture of compound 33 (4.0 g, 3.15 mmol)

and carbon tetrabromide (1.5 g, 4.26 mmol) in the minimum

amount of anhydrous CH₂Cl₂required to dissolve these reagents.

After stirring under argon for 20 min, further carbon tetrabromide

and triphenylphosphane were added in 1.25-equiv. amounts at 10-

min intervals until TLC showed no starting benzyl alcohol any-

more. The reaction mixture was then poured into water and ex-

tracted with CH₂Cl₂(3×20 mL), the combined extracts were dried

with MgSO₄, and the solvents evaporated. The product was puri-

fied by column chromatography on silica gel eluting with CH₂Cl₂

to give 34 as a pale-yellow solid (3.46 g, yield 82.4%). M.p. 64–

65 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.80 (m, 8 H,

-CH₂-), 2.07 (m, 8 H, -CH₂-), 3.88 (t, J = 6.1 Hz, 8 H, -OCH₂-),

4.36 (m, 10 H, -NCH₂-, -CH₂Br), 4.89 (s, 4 H, -OCH₂-), 6.30 (s, 2

H, Ph-H), 6.48 (s, 5 H, Ph-H), 6.60 (s, 2 H, Ph-H), 7.21 [t, J =

7.0 Hz, 8 H, Ph-H (CZ)], 7.40 [d, J = 8.1 Hz, 8 H, Ph-H (CZ)],

7.44 [t, J = 7.2 Hz, 8 H, Ph-H (CZ)], 8.10 [d, J = 7.7 Hz, 8 H, Ph-

H (CZ)] ppm.

(CZ)₄-(G-2)-COOH (31): A mixture of compound 29 (1.3 g,

1.0 mmol) and KOH (3.0 g, 53.6 mmol) in tetrahydrofuran/meth-

anol (20 mL/40 mL) was refluxed with vigorous stirring for 30 h.

After cooling to room temperature, the mixture was concentrated

to dryness under reduced pressure and the residue was acidified

with 10% aqueous HCl solution (400 mL). The precipitate was fil-

tered off and washed with ethanol to give 31 as a white solid (1.1 g,

yield 85.8%). The product was used directly in the next reaction

(CZ)₈-(G-3)-COOCH₃(35): A mixture of compound 34 (3.0 g,

2.2 mmol), methyl 3,5-dihydroxybenzoate (0.17 g, 1.0 mmol), anhy-

drous potassium carbonate (1.2 g, 8.7 mmol), and 18-crown-6

(0.4 g, 1.4 mmol) in anhydrous THF (50 mL) was refluxed with vig-

orous stirring under argon for 60 h. After cooling to room tempera-

ture, the mixture was concentrated to dryness under reduced pres-

sure, the residue was partitioned between CH₂Cl₂and H₂O, and

the aqueous layer was extracted with CH₂Cl₂(3×30 mL). The

combined organic layers were dried with anhydrous MgSO₄and

the solvents evaporated. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂/CCl₄(2:1) to give

1

without further purification. M.p. 94–96 °C. H NMR (500 MHz,

CDCl₃, 25 °C): δ = 1.80 (m, 8 H, -CH₂-), 2.06 (m, 8 H, -CH₂-),

3.90 (t, J = 6.0 Hz, 8 H, -OCH₂-), 4.40 (t, J = 6.7 Hz, 8 H,

-NCH₂-), 4.92 (s, 4 H, -OCH₂-), 6.32 (s, 2 H, Ph-H), 6.50 (s, 4 H,

Ph-H), 6.75 (s, 1 H, Ph-H), 7.20 [t, J = 7.1 Hz, 8 H, Ph-H (CZ)],

7.25 (s, 2 H, Ph-H), 7.30–7.50 [m, 16 H, Ph-H (CZ)], 8.12 [d, J =

7.6 Hz, 8 H, Ph-H (CZ)] ppm. MS (ESI): m/z = 1321.5 [M⁺+ K].

(OXZ)₄-(G-2)-COOH (32): A mixture of compound 30 (1.0 g,

0.64 mmol) and KOH (1.0 g, 17.9 mmol) in tetrahydrofuran/meth-

anol (40 mL/20 mL) was refluxed with vigorous stirring for 30 h.

After cooling to room temperature, the mixture was concentrated

to dryness under reduced pressure and the residue was acidified

with 10% aqueous HCl solution (400 mL). The precipitate was fil-

tered off and washed with ethanol to give 32 as a white solid

(0.85 g, yield 85.8%). The product was used directly in the next

1

35 as a white solid (2.26 g, yield 84.7%). M.p. 76–78 °C. H NMR

(500 MHz, CDCl₃, 25 °C): δ = 1.75 (m, 16 H, -CH₂-), 2.00 (m, 16

H, -CH₂-), 3.62 (s, 3 H, -OCH₃), 3.85 (m, 16 H, -OCH₂-), 4.31 (t,

J = 6.7 Hz, 16 H, -NCH₂-), 4.89 (s, 8 H, -OCH₂-), 4.93 (s, 4 H,

-OCH₂-), 6.30–6.73 (19 H, Ph-H), 7.19 [m, 18 H, Ph-H, Ph-H

(CZ)], 7.35–7.50 [td, J = 7.0, J = 8.0 Hz, 32 H, Ph-H (CZ)], 8.06

[d, J = 7.6 Hz, 16 H, Ph-H (CZ)] ppm. MS (MALDI-TOF): m/z =

2709.3 [M⁺+ K].

1

reaction without further purification. M.p. 146–148 °C. H NMR

(500 MHz, CDCl₃, 25 °C): δ = 1.38 (s, 36 H, -CH₃), 5.05 (s, 4 H,

-OCH₂-), 5.16 (s, 8 H, -OCH₂-), 6.59 (s, 2 H, Ph-H), 6.71 (s, 4 H,

Ph-H), 6.75 (s, 1 H, Ph-H), 7.20 (s, 2 H, Ph-H), 7.58 [m, 16 H, Ph-

H (OXZ)], 8.08 [d, J = 8.2 Hz, 8 H, Ph-H (OXZ)], 8.17 [d, J =

8.1 Hz, 8 H, Ph-H (OXZ)] ppm. MS (MALDI-TOF): m/z = 1559.2

[M⁺].

(CZ)₈-(G-3)-COOH (36): A mixture of compound 35 (3.4 g,

1.3 mmol) and KOH (1.0 g, 17.9 mmol) in tetrahydrofuran/meth-

anol (30 mL/30 mL) was refluxed with vigorous stirring for 30 h.

After cooling to room temperature, the mixture was concentrated

to dryness under reduced pressure and the residue was acidified

with 10% aqueous HCl solution (400 mL). The precipitate was fil-

tered off and washed with ethanol to give 36 as a white solid (2.7 g,

(CZ)₄-(G-2)-CH₂OH (33): A mixture of compound 27 (8.3 g,

14.5 mmol), 3,5-dihydroxybenzyl alcohol (1.0 g, 7.1 mmol), anhy-

drous potassium carbonate (3.4 g, 24.6 mmol), and 18-crown-6 yield 78.3%). The product was used directly in the next reaction

Eur. J. Org. Chem. 2006, 986–1001

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997

J. Pan, W. Zhu, S. Li, J. Xu, H. Tian

FULL PAPER

without further purification. M.p. 121–123 °C. ¹H NMR

2 H, -NCH₂), 6.62 (s, 1 H, Ph-H), 7.12–7.20 (m, 3 H, Ph-H, naph-

(500 MHz, CDCl₃, 25 °C): δ = 1.78 (m, 16 H, -CH₂-), 2.04 (m, 16 thalene-H), 7.22 [t, J = 7.3 Hz, 2 H, Ph-H (CZ)], 7.40–7.50 [td, J

H, -CH₂-), 3.85 (m, 16 H, -OCH₂-), 4.31 (t, J = 6.7 Hz, 16 H, = 7.5, J = 7.8 Hz, 4 H, Ph-H (CZ)], 7.68 (t, J = 7.9 Hz, 1 H,

-NCH₂-), 4.85–4.95 (s, 12 H, -OCH₂-), 6.32–6.75 (m, 19 H, Ph-H), naphthalene-H), 8.10 [d, J = 7.7 Hz, 2 H, Ph-H (CZ)], 8.39 (d, J =

7.19 [m, 18 H, Ph-H, Ph-H (CZ)], 7.35–7.50 [m, 32 H, Ph-H (CZ)],

8.06 [d, J = 7.6 Hz, 16 H, Ph-H (CZ)] ppm. MS (MALDI-TOF):

m/z = 2695.3 [M⁺+ K].

8.3 Hz, 1 H, naphthalene-H), 8.49 (d, J = 8.1 Hz, 1 H, naphtha-

lene-H), 8.58 (d, J = 7.2 Hz, 1 H, naphthalene-H) ppm. MS (ESI):

m/z = 732.3 [M⁺+ Na].

(CZ)₁-(G-1)-OH (41): A mixture of 9-(4-bromobutyl)-9H-carba-

zole (2.0 g, 6.62 mmol), benzene-1,4-diol (3.5 g, 31.8 mmol), anhy-

drous potassium carbonate (1.0 g, 7.25 mmol), and 18-crown-6

(0.4 g, 1.4 mmol) in anhydrous acetone (70 mL) was refluxed with

vigorous stirring under argon for 36 h. After cooling to room tem-

perature, the mixture was concentrated to dryness under reduced

pressure. The residue was partitioned between CH₂Cl₂and H₂O

and the aqueous layer was extracted with CH₂Cl₂(3×30 mL). The

combined organic layers were dried with anhydrous MgSO₄and

the solvents evaporated. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂to give 41 as a

white solid (1.31 g, yield 59.3 %). M.p. 130–131 °C. ¹H NMR

(500 MHz, CDCl₃, 25 °C): δ = 1.82 (m, 2 H, -CH₂-), 2.08 (m, 2

H, -CH₂-), 3.88 (t, J = 6.1 Hz, 2 H, -OCH₂-), 4.40 (m, 3 H,

-NCH₂-, HO-Ph), 6.73 (s, 4 H, Ph-H), 7.23 [t, J = 7.0 Hz, 2 H, Ph-

H (CZ)], 7.40–7.48 [td, J = 7.2, J = 8.1 Hz, 4 H, Ph-H (CZ)], 8.10

[d, J = 7.7 Hz, 2 H, Ph-H (CZ)] ppm.

(CZ)₂-PTCDI-CH₂OH (38): A mixture of N,NЈ-bis(2-hydroxy-

ethyl)-1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis-

(dicarboximide) (0.25 g, 0.28 mmol), compound 19 (0.17 g,

0.28 mmol), DCC (0.5 g, 2.4 mmol), and 4-(dimethylamino)pyri-

dine (DMAP; 0.2 g, 1.6 mmol) in anhydrous CH₂Cl₂(30 mL) was

stirred at room temperature for 24 h. The mixture was then concen-

trated to dryness and the product was purified by column

chromatography on silica gel eluting with CH₂Cl₂/CH₃COCH₃

(20:1) to give 38 as a dark-red solid (16 mg, yield 3.9%). M.p. Ͼ

280 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.76 (m, 4 H,

-CH₂-), 1.98 (m, 4 H, -CH₂-), 2.26 (s, 6 H, -CH₃), 2.31 (s, 6 H,

-CH₃), 3.88 (t, J = 6.1 Hz, 4 H, -OCH₂-), 3.91 (t, J = 5.3 Hz, 2 H,

HOCH₂-), 4.30 (t, J = 7.1 Hz, 4 H, -NCH₂-), 4.37 (m, 2 H,

-NCH₂-), 4.56 (s, 4 H, -OCH₂, -NCH₂-), 6.50 (s, 1 H, Ph-H), 6.78

(d, J = 7.6 Hz, 8 H, Ph-H), 7.00 (d, J = 8.3 Hz, 4 H, Ph-H), 7.05

(d, J = 8.3 Hz, 4 H, Ph-H), 7.08 (s, 2 H, Ph-H), 7.18 [t, J = 7.3 Hz,

4 H, Ph-H (CZ)], 7.35–7.45 [td, J = 7.3, J = 8.1 Hz, 8 H, Ph-H

(CZ)], 8.06 [d, J = 7.8 Hz, 4 H, Ph-H (CZ)], 8.09 (s, 2 H, perylene-

H), 8.13 (s, 2 H, perylene-H) ppm.

(CZ)₂-(G-1)-OH (42): A mixture of benzene-1,4-diol (4.6 g,

41.8 mmol), compound 27 (2.7 g, 4.18 mmol), anhydrous potas-

sium carbonate (0.65 g, 4.71 mmol), and 18-crown-6 (0.4 g,

1.4 mmol) in anhydrous acetone (70 mL) was refluxed with vigor-

ous stirring under argon for 60 h. After cooling to room tempera-

ture, the mixture was concentrated to dryness under reduced pres-

sure. The residue was partitioned between CH₂Cl₂and H₂O and

the aqueous layer was extracted with CH₂Cl₂(3 ×30 mL). The

combined organic layers were dried with anhydrous MgSO₄and

the solvents evaporated. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂to give 42 as a

white solid (2.30 g, yield 81.6 %). M.p. 151–152 °C. ¹H NMR

(500 MHz, CDCl₃, 25 °C): δ = 1.82 (m, 4 H, -CH₂-), 2.07 (m, 4

H, -CH₂-), 3.91 (t, J = 6.1 Hz, 4 H, -OCH₂-), 4.39 (t, J = 7.1 Hz,

4 H, -NCH₂-), 4.89 (s, 2 H, -OCH₂-), 6.31 (s, 1 H, Ph-H), 6.51 (s,

2 H, Ph-H), 6.72 (d, J = 8.8 Hz, 2 H, Ph-H), 6.82 (d, J = 8.8 Hz,

2 H, Ph-H), 7.22 [t, J = 7.0 Hz, 4 H, Ph-H (CZ)], 7.40–7.48 [td, J

= 7.3, J = 8.1 Hz, 8 H, Ph-H (CZ)], 8.10 [d, J = 7.6 Hz, 4 H, Ph-

H (CZ)] ppm.

(CZ)₁-(NP)₁-(G-1)-COOCH₃(39): A mixture of N-(4-bromobu-

tyl)-9H-carbazole (0.73 g, 2.4 mmol), N-(4-bromobutyl)-4-(piperi-

din-1-yl)-1,8-naphthalenedicarboximide (1.0 g, 2.4 mmol), methyl

3,5-dihydroxybenzoate (0.4 g, 2.4 mmol), anhydrous potassium car-

bonate (2.0 g, 14.5 mmol), and 18-crown-6 (0.4 g, 1.4 mmol) in an-

hydrous THF (50 mL) was refluxed with vigorous stirring under

argon for 60 h. After cooling to room temperature, the mixture was

concentrated to dryness under reduced pressure. The residue was

partitioned between CH₂Cl₂and water and the aqueous layer was

extracted with CH₂Cl₂(3×40 mL). The combined organic layers

were dried with anhydrous MgSO₄and the solvents evaporated.

The product was purified by column chromatography on silica gel

eluting with CH₂Cl₂/CCl₄(1:3) to give 39 as a yellow solid (0.57 g,

1

yield 32.9%). M.p. 66–67 °C. H NMR (500 MHz, CDCl₃, 25 °C):

δ = 1.76–1.98 (m, 12 H, -CH₂), 2.12 (m, 2 H, -CH₂), 3.25 (s, 4 H,

-NCH₂), 3.88 (s, 3 H, -OCH₃), 3.98 (t, J = 6.0 Hz, 2 H, -OCH₂),

4.02 (t, J = 5.1 Hz, 2 H, -OCH₂), 4.25 (t, J = 6.5 Hz, 2 H, -NCH₂),

4.38 (t, J = 7.0 Hz, 2 H, -NCH₂), 6.60 (s, 1 H, Ph-H), 7.10–7.20

(m, 3 H, Ph-H, naphthalene-H), 7.23 [t, J = 7.2 Hz, 2 H, Ph-H

(CZ)], 7.40–7.50 [td, J = 7.6, J = 8.0 Hz, 4 H, Ph-H (CZ)], 7.68 (t,

J = 8.0 Hz, 1 H, naphthalene-H), 8.10 [d, J = 7.7 Hz, 2 H, Ph-H

(CZ)], 8.38 (d, J = 8.4 Hz, 1 H, naphthalene-H), 8.50 (d, J =

8.3 Hz, 1 H, naphthalene-H), 8.58 (d, J = 7.2 Hz, 1 H, naphtha-

lene-H) ppm.

(CZ)₄-(G-2)-OH (43): A mixture of benzene-1,4-diol (5.0 g,

45.5 mmol), compound 34 (4.0 g, 3.0 mmol), anhydrous potassium

carbonate (0.5 g, 3.62 mmol), and 18-crown-6 (0.4 g, 1.4 mmol) in

anhydrous acetone (70 mL) was refluxed with vigorous stirring un-

der argon for 60 h. After cooling to room temperature, the mixture

was concentrated to dryness under reduced pressure. The residue

was partitioned between CH₂Cl₂and H₂O and the aqueous layer

was extracted with CH₂Cl₂(3×30 mL). The combined organic lay-

ers were dried with anhydrous MgSO₄and the solvents evaporated.

The product was purified by column chromatography on silica gel

(CZ)₁-(NP)₁-(G-1)-COOH (40): A mixture of compound 39

(0.57 g, 0.8 mmol) and KOH (3.0 g, 53.6 mmol) in tetrahydrofuran/

methanol (40 mL/20 mL) was refluxed with vigorous stirring for eluting with CH₂Cl₂to give 43 as a white solid (2.80 g, yield

1

20 h. After cooling to room temperature, the mixture was concen-

trated to dryness under reduced pressure and the residue was acidi-

fied with 10% aqueous HCl solution (300 mL). The precipitate was

filtered off and washed with ethanol to give 40 as a yellow solid

(0.45 g, yield 80.7%). The product was used directly in the next

68.6%). M.p. 61–63 °C. H NMR (500 MHz, CDCl₃, 25 °C): δ =

1.80 (m, 8 H, -CH₂-), 2.05 (m, 8 H, -CH₂-), 3.88 (t, J = 6.0 Hz, 8

H, -OCH₂-), 4.32 (s, 1 H, HO-Ph), 4.37 (t, J = 7.0 Hz, 8 H,

-NCH₂-), 4.88 (s, 2 H, -OCH₂-), 4.90 (s, 4 H, -OCH₂-), 6.30 (s, 2

H, Ph-H), 6.49 (s, 4 H, Ph-H), 6.51 (s, 1 H, Ph-H), 6.62 (s, 2 H,

Ph-H), 6.67 (d, J = 8.9 Hz, 2 H, Ph-H), 6.76 (d, J = 8.9 Hz, 2 H,

Ph-H), 7.21 [t, J = 7.1 Hz, 8 H, Ph-H (CZ)], 7.40–7.50 [td, J = 7.5,

1

reaction without further purification. M.p. 110–111 °C. H NMR

(500 MHz, CDCl₃, 25 °C): δ = 1.76–2.12 (m, 14 H, -CH₂), 3.20 (s,

4 H, -NCH₂), 3.98 (t, J = 5.3 Hz, 2 H, -OCH₂), 4.02 (t, J = 5.1 Hz, J = 8.0 Hz, 16 H, Ph-H (CZ)], 8.09 [d, J = 7.7 Hz, 8 H, Ph-H (CZ)]

2 H, -OCH₂), 4.25 (t, J = 6.2 Hz, 2 H, -NCH₂), 4.39 (t, J = 6.8 Hz, ppm.

998

www.eurjoc.org

Eur. J. Org. Chem. 2006, 986–1001

Carrier-Transporting Dendrimers with a Luminescent Core

FULL PAPER

Preparation of CZ- or OXZ-Terminated Imide-Type Dendrimers

oximide) (0.25 g, 0.28 mmol), compound 20 (0.8 g, 1.1 mmol),

DCC (0.5 g, 2.4 mmol), and DMAP (0.2 g, 1.6 mmol) in anhydrous

CH₂Cl₂(30 mL) was stirred at room temperature for 24 h. During

this time more DCC and DMAP were added, as required, until

TLC showed no remaining starting materials. The mixture was then

concentrated to dryness. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂/CH₃COCH₃

(20:1) to give dendrimer 4 as a dark-red solid (0.29 g, yield 44.3%).

2CZ-(G-1)-PTCDI (1): A mixture of N,NЈ-bis(2-hydroxyethyl)-

1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis(dicarb-

oximide) (0.3 g, 0.33 mmol), compound 15 (0.48 g, 1.3 mmol),

DCC (0.5 g, 2.4 mmol), and DMAP (0.2 g, 1.6 mmol) in anhydrous

CH₂Cl₂(25 mL) was stirred at room temperature for 24 h. During

this time more DCC and DMAP were added, as required, until

TLC showed no remaining starting materials. The mixture was then

concentrated to dryness and the product was purified by column

chromatography on silica gel eluting with CH₂Cl₂to give den-

drimer 1 as a dark-red solid (0.34 g, yield 64.2%). M.p. 136–137 °C.

¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.85 (m, 4 H, -CH₂-), 2.10

(m, 4 H, -CH₂-), 2.30 (s, 12 H, -CH₃), 3.90 (t, J = 6.1 Hz, 4 H,

-OCH₂-), 4.40 (t, J = 7.0 Hz, 4 H, -NCH₂-), 4.70 (s, 8 H,

-OCH₂-, -NCH₂-), 6.75 (d, J = 7.0 Hz, 4 H, Ph-H), 6.80 (d, J =

8.4 Hz, 8 H, Ph-H), 7.06 (d, J = 8.4 Hz, 8 H, Ph-H), 7.20 [t, J =

7.7 Hz, 4 H, Ph-H (CZ)], 7.40–7.50 [td, J = 7.8, J = 8.2 Hz, 8 H,

Ph-H (CZ)], 7.80 (d, J = 9.0 Hz, 4 H, Ph-H), 8.10 [d, J = 7.8 Hz,

4 H, Ph-H (CZ)], 8.12 (s, 4 H, perylene-H) ppm. MS (ESI): m/z =

1608.6 [M⁺+ Na].

1

M.p. 179–180 °C. H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.38 (s,

36 H, -CH₃), 2.25 (s, 12 H, -CH₃), 4.55 (s, 8 H, -CH₂-), 5.03 (s, 8

H, -OCH₂-), 6.76 (m, 10 H, Ph-H), 7.02 (d, J = 8.3 Hz, 8 H, Ph-

H), 7.21 (s, 4 H, Ph-H), 7.50 [d, J = 8.2 Hz, 8 H, Ph-H (OXZ)],

7.55 [d, J = 8.4 Hz, 8 H, Ph-H (OXZ)], 8.05 [m, 16 H, Ph-H

(OXZ)], 8.13 (s, 4 H, perylene-H) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 20.99, 31.35, 34.16, 35.34, 69.56, 108.47, 119.54,

119.93, 120.08, 120.56, 121.19, 122.43, 123.75, 126.31, 127.00,

127.27, 128.02, 130.74, 132.23, 133.01, 134.56, 140.44, 153.08,

155.64, 156.41, 159.55, 163.56, 164.27, 164.92, 166.00 ppm. MS

(MALDI-TOF): m/z = 2357.9 [M⁺+ Na].

6CZ-(G-1)-PTCDI (5): A mixture of N,NЈ-bis(2-hydroxyethyl)-

2OXZ-(G-1)-PTCDI (2): A mixture of N,NЈ-bis(2-hydroxyethyl)- 1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis(dicarb-

1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis(dicarb-

oximide) (0.2 g, 0.22 mmol), compound 16 (0.4 g, 0.93 mmol),

DCC (0.5 g, 2.4 mmol), and DMAP (0.2 g, 1.6 mmol) in anhydrous

oximide) (0.2 g, 0.22 mmol), compound 23 (0.6 g, 0.72 mmol),

DCC (0.5 g, 2.4 mmol), and DMAP (0.2 g, 1.6 mmol) in anhydrous

CH₂Cl₂(30 mL) was stirred at room temperature for 24 h. During

CH₂Cl₂(40 mL) was stirred at room temperature for 24 h. During this time more DCC and DMAP were added, as required, until

this time more DCC and DMAP were added, as required, until

TLC showed no remaining starting materials. The mixture was then

concentrated to dryness. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂/CH₃COCH₃

TLC showed no remaining starting materials. The mixture was then

concentrated to dryness. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂/CH₃COCH₃

(200:1) to give dendrimer 5 as a dark-red solid (0.27 g, yield

49.3%). M.p. 120–122 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ

(20:1) to give dendrimer 2 as a dark-red solid (0.21 g, yield 55.4%).

1

M.p. 153–155 °C. H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.38 (s, = 1.53 (m, 4 H, -CH₂-), 1.65 (m, 8 H, -CH₂-), 1.85 (m, 12 H,

18 H, -CH₃), 2.30 (s, 12 H, -CH₃), 4.55 (s, 8 H, -CH₂-), 5.15 (s, 4

H, -OCH₂-), 6.85 (d, J = 8.4 Hz, 8 H, Ph-H), 6.91 (d, J = 8.4 Hz,

4 H, Ph-H), 7.08 (d, J = 8.3 Hz, 8 H, Ph-H), 7.58 [t, J = 8.6 Hz, 8

H, Ph-H (OXZ)], 7.90 (d, J = 8.7 Hz, 4 H, Ph-H), 8.07 [d, J =

-CH₂-), 2.20 (s, 12 H, -CH₃), 3.80 (m, 12 H, -OCH₂-), 4.05 (t, J =

7.2 Hz, 4 H, -NCH₂-), 4.15 (t, J = 7.1 Hz, 8 H, -NCH₂-), 4.51 (s,

8 H, -OCH₂-, -NCH₂-), 6.67 (d, J = 8.4 Hz, 8 H, Ph-H), 6.90 (d,

J = 8.3 Hz, 8 H, Ph-H), 7.10–7.20 [m, 20 H, Ph-H, Ph-H (CZ)],

8.4 Hz, 4 H, Ph-H (OXZ)], 8.16 [m, 8 H, perylene-H, Ph-H (OXZ)] 7.25 [m, 8 H, Ph-H (CZ)], 7.33 [t, J = 7.5 Hz, 12 H, Ph-H (CZ)],

ppm. MS (ESI): m/z = 1746.3 [M⁺+ Na].

8.0–8.05 [m, 12 H, Ph-H (CZ)], 8.10 (s, 4 H, perylene-H) ppm. ¹³C

NMR (100 MHz, CDCl₃): δ = 20.62, 25.61, 26.80, 27.74, 39.23,

42.42, 42.53, 62.54, 68.39, 72.66, 108.00, 108.53, 108.67, 118.75,

118.79, 119.32, 119.68, 120.29, 120.35, 122.21, 122.79, 124.67,

125.53, 125.56, 130.42, 132.77, 134.18, 140.24, 140.29, 141.68,

152.29, 152.88, 156.01, 163.28, 165.94 ppm. MS (MALDI-TOF):

m/z = 2558.3 [M⁺+ Na].

4CZ-(G-1)-PTCDI (3): A mixture of N,NЈ-bis(2-hydroxyethyl)-

1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis(dicarb-

oximide) (0.2 g, 0.22 mmol), compound 19 (0.5 g, 0.84 mmol),

DCC (0.5 g, 2.4 mmol), and DMAP (0.2 g, 1.6 mmol) in anhydrous

CH₂Cl₂(30 mL) was stirred at room temperature for 24 h. During

this time more DCC and DMAP were added, as required, until

TLC showed no remaining starting materials. The mixture was then

concentrated to dryness. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂to give den-

drimer 3 as a dark-red solid (0.24 g, yield 52.5%). M.p. 230–233 °C.

¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.65 (m, 8 H, -CH₂-), 1.90

(m, 8 H, -CH₂-), 2.15 (s, 12 H, -CH₃), 3.80 (t, J = 6.1 Hz, 8 H,

-OCH₂-), 4.20 (t, J = 7.1 Hz, 8 H, -NCH₂-), 4.48 (s, 8 H,

-OCH₂-, -NCH₂-), 6.40 (s, 2 H, Ph-H), 6.64 (d, J = 8.4 Hz, 8 H,

Ph-H), 6.88 (d, J = 8.4 Hz, 8 H, Ph-H), 7.05 (s, 4 H, Ph-H), 7.10

[t, J = 7.6 Hz, 8 H, Ph-H (CZ)], 7.25–7.35 [td, J = 7.4, J = 8.0 Hz,

16 H, Ph-H (CZ)], 7.95 [d, J = 7.7 Hz, 8 H, Ph-H (CZ)], 8.05 (s, 4

H, perylene-H) ppm. ¹³C NMR (100 MHz, CDCl₃): δ = 20.96,

25.92, 26.98, 39.40, 42.82, 62.66, 67.88, 107.31, 107.82, 108.80,

119.03, 119.56, 119.98, 120.57, 120.61, 120.61, 122.40, 123.02,

125.85, 130.69, 131.92, 132.98, 134.42, 140.48, 153.15, 156.25,

159.98, 163.56, 166.31 ppm. MS (MALDI-TOF): m/z = 2058.9 [M⁺

+ 1].

6OXZ-(G-1)-PTCDI (6): A mixture of N,NЈ-bis(2-hydroxyethyl)-

1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis(dicarb-

oximide) (0.3 g, 0.33 mmol), compound 24 (1.0 g, 0.96 mmol),

DCC (0.5 g, 2.4 mmol), and DMAP (0.2 g, 1.6 mmol) in anhydrous

CH₂Cl₂(50 mL) was stirred at room temperature for 24 h. During

this time more DCC and DMAP were added, as required, until

TLC showed no remaining starting materials. The mixture was then

concentrated to dryness. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂/CH₃COCH₃

(20:1) to give dendrimer 6 as a dark-red solid (0.36 g, yield 37.0%).

1

M.p. 191–193 °C. H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.36 (s,

54 H, -CH₃), 2.25 (s, 12 H, -CH₃), 4.50 (s, 8 H, -CH₂-), 5.00 (s, 8

H, -OCH₂-), 5.20 (s, 4 H, -OCH₂-), 6.75 (d, J = 8.3 Hz, 8 H, Ph-

H), 7.00 (d, J = 8.4 Hz, 8 H, Ph-H), 7.32 (s, 4 H, Ph-H), 7.45–7.55

[m, 24 H, Ph-H (OXZ)], 8.00 [m, 24 H, Ph-H (OXZ)], 8.10 (s, 4 H,

perylene-H) ppm. ¹³C NMR (100 MHz, CDCl₃): δ = 21.36, 31.76,

35.72, 39.75, 63.05, 70.86, 75.29, 109.57, 120.29, 120.47, 120.98,

4OXZ-(G-1)-PTCDI (4): A mixture of N,NЈ-bis(2-hydroxyethyl)- 121.63, 122.90, 124.24, 124.30, 126.68, 127.39, 127.42, 127.62,

1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis(dicarb- 128.51, 129.17, 131.16, 135.02, 140.78, 141.88, 152.72, 153.48,

Eur. J. Org. Chem. 2006, 986–1001

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999

J. Pan, W. Zhu, S. Li, J. Xu, H. Tian

FULL PAPER

155.92, 155.99, 156.85, 163.95, 164.62, 164.76, 165.34 ppm. MS 24 h. During this time more DCC and DMAP were added, as re-

(MALDI-TOF): m/z = 2950.0 [M⁺].

quired, until TLC showed no remaining starting materials. The

mixture was then concentrated to dryness. The product was puri-

fied by column chromatography on silica gel eluting with CH₂Cl₂/

CH₃COCH₃(200:1) to give 10 as a dark-red solid (75 mg, yield

29.9%). M.p. 139–140 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ

= 1.70–1.88 (m, 24 H, -CH₂), 1.97 (m, 4 H, -CH₂), 2.25 (s, 12 H,

-CH₃), 3.20 (s, 8 H, -NCH₂), 3.87 (m, 8 H, -OCH₂), 4.13 (s, 4 H,

-NCH₂), 4.30 (t, J = 7.1 Hz, 4 H, -NCH₂), 4.52 (s, 8 H, -CH₂),

6.52 (s, 2 H, Ph-H), 6.75 (d, J = 8.4 Hz, 8 H, Ph-H), 7.00 (d, J =

8.4 Hz, 8 H, Ph-H), 7.08 (s, 4 H, Ph-H), 7.12 (d, J = 8.1 Hz, 2 H,

naphthalene-H), 7.18 [t, J = 7.5 Hz, 4 H, Ph-H (CZ)], 7.35–7.45

[td, J = 7.6, J = 8.1 Hz, 8 H, Ph-H (CZ)], 7.63 (t, J = 8.2 Hz, 2 H,

naphthalene-H), 8.05 [m, 8 H, perylene-H, Ph-H (CZ)], 8.32 (d, J

= 8.0 Hz, 2 H, naphthalene-H), 8.38 (d, J = 8.2 Hz, 2 H, naphtha-

lene-H), 8.50 (d, J = 7.3 Hz, 2 H, naphthalene-H) ppm. ¹³C NMR

(100 MHz, CDCl₃): δ = 21.35, 24.96, 25.35, 26.30, 26.84, 27.39,

39.79, 40.34, 43.24, 55.13, 62.86, 68.26, 68.41, 108.25, 108.32,

109.21, 115.25, 119.40, 120.32, 120.46, 120.90, 121.00, 122.76,

123.43, 123.65, 125.93, 126.24, 130.44, 131.08, 131.55, 132.25,

133.21, 134.78, 140.91, 153.60, 156.69, 157.81, 160.32, 160.54,

163.90, 164.59, 165.09, 166.72 ppm. MS (MALDI-TOF): m/z =

2286.1 [M⁺].

8CZ-(G-2)-PTCDI (7): A mixture of N,NЈ-bis(2-hydroxyethyl)-

1,6,7,12-tetrakis4-methylphenoxy)-3,4:9,10-perylenebis(dicarb-

oximide) (0.2 g, 0.22 mmol), compound 31 (0.8 g, 0.62 mmol),

DCC (0.5 g, 2.4 mmol), and DMAP (0.2 g, 1.6 mmol) in anhydrous

CH₂Cl₂(30 mL) was stirred at room temperature for 24 h. During

this time more DCC and DMAP were added, as required, until

TLC showed no remaining starting materials. The mixture was then

concentrated to dryness. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂to give den-

drimer 7 as a violet-red solid (0.19 g, yield 25.2 %). M.p. 115–

117 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.70 (m, 16 H,

-CH₂-), 2.00 (m, 16 H, -CH₂-), 2.18 (s, 12 H, -CH₃), 3.80 (tt, J =

6.1, J = 6.1 Hz, 16 H, -OCH₂-), 4.30 (tt, J = 7.1, J = 7.0 Hz, 16

H, -NCH₂-), 4.44 (s, 4 H, -CH₂-), 4.45 (s, 4 H, -CH₂-), 4.80 (s, 8

H, -OCH₂-, -NCH₂-), 6.20 (s, 4 H, Ph-H), 6.40 (s, 8 H, Ph-H), 6.65

(s, 2 H, Ph-H), 6.72 (d, J = 8.4 Hz, 8 H, Ph-H), 6.90 (d, J = 8.4 Hz,

8 H, Ph-H), 7.18 [m, 20 H, Ph-H, Ph-H (CZ)], 7.30–7.40 [m, 32

H, Ph-H (CZ)], 8.05 [m, 20 H, Ph-H (CZ), perylene-H] ppm. MS

(MALDI-TOF): m/z = 3457.4 [M⁺+ Na].

8OXZ-(G-2)-PTCDI (8): A mixture of N,NЈ-bis(2-hydroxyethyl)-

1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis(dicarb-

oximide) (0.2 g, 0.22 mmol), compound 32 (2.0 g, 1.28 mmol),

DCC (0.5 g, 2.4 mmol), and DMAP (0.2 g, 1.6 mmol) in anhydrous

CH₂Cl₂(40 mL) was stirred at room temperature for 24 h. During

this time more DCC and DMAP were added, as required, until

TLC showed no remaining starting materials. The mixture was then

concentrated to dryness. The product was purified by column

chromatography on silica gel eluting with CH₂Cl₂/CH₃COCH₃

(10:1) to give dendrimer 8 as a dark-red solid (0.12 g, yield 13.7%).

Preparation of CZ-Terminated Bay-Type Dendrimers

4CZ-(G-1)-PTCDI (11): A mixture of N,NЈ-bis(2-hydroxyethyl)-

1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis(dicarb-

oximide) (0.85 g, 1.0 mmol), compound 41 (1.65 g, 5.0 mmol), and

anhydrous potassium carbonate (6.7 g, 48.6 mmol) in anhydrous

DMF (40 mL) was stirred vigorously at 140 °C under argon for

24 h. After cooling to room temperature, the mixture was added to

H₂O (200 mL). The precipitate was filtered off and dried. The prod-

uct was purified by column chromatography on silica gel eluting

with CH₂Cl₂to give 11 as a dark-red solid (0.34 g, yield 16.8%).

M.p. 154–156 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.12 (d,

J = 6.6 Hz, 24 H, -CH₃), 1.77 (m, 8 H, -CH₂-), 2.04 (m, 8 H,

-CH₂-), 2.68 (m, 4 H, -CH-), 3.83 (t, J = 6.0 Hz, 8 H, -OCH₂-),

4.37 (t, J = 7.0 Hz, 8 H, -NCH₂-), 6.74 (d, J = 9.0 Hz, 8 H, Ph-

H), 6.89 (d, J = 8.9 Hz, 8 H, Ph-H), 7.23 [t, J = 7.4 Hz, 8 H, Ph-

H (CZ)], 7.27 (s, 4 H, Ph-H), 7.28 (s, 2 H, Ph-H), 7.38–7.48 [td, J

= 7.4, J = 8.2 Hz, 16 H, Ph-H (CZ)], 8.09 [d, J = 7.8 Hz, 8 H, Ph-

H (CZ)], 8.16 (s, 4 H, perylene-H) ppm. MS (MALDI-TOF): m/z

= 2028.3 [M⁺].

1

M.p. 156–158 °C. H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.35 (s,

72 H, -CH₃), 2.21 (s, 12 H, -CH₃), 4.55 (s, 8 H, -CH₂-), 4.98 (s, 24

H, -OCH₂-), 6.42 (s, 4 H, Ph-H), 6.50–6.8 (m, 26 H, Ph-H), 7.11

(s, 4 H, Ph-H), 7.55 [m, 32 H, Ph-H (OXZ)], 8.00–8.10 [m, 36 H,

Ph-H (OXZ), perylene-H] ppm. MS (MALDI-TOF): m/z = 3972.4

[M⁺].

2CZ-2OXZ-(G-1)-PTCDI (9): A mixture of 38 (0.034 g,

0.023 mmol), 20 (0.10 g, 0.14 mmol), DCC (0.25 g, 1.2 mmol), and

DMAP (0.1 g, 0.8 mmol) in anhydrous CH₂Cl₂(20 mL) was stirred

at room temperature for 24 h. During this time more DCC and

DMAP were added, as required, until TLC showed no remaining

starting materials. The mixture was then concentrated to dryness.

The product was purified by column chromatography on silica gel

eluting with CH₂Cl₂/CH₃COCH₃(20:1) to give 9 as a dark-red so-

lid (8 mg, yield 15.8 %). M.p. 142–143 °C. ¹H NMR (500 MHz,

CDCl₃, 25 °C): δ = 1.36 (s, 18 H, -CH₃), 1.75 (m, 4 H, -CH₂), 1.95

(m, 4 H, -CH₂), 2.25 (2×s, 12 H, -CH₃), 3.87 (t, J = 6.0 Hz, 4 H,

-OCH₂), 4.30 (t, J = 6.0 Hz, 4 H, -NCH₂), 4.57 (s, 8 H, -CH₂), 5.05

(s, 4 H, -OCH₂), 6.50 (s, 1 H, Ph-H), 6.75 (m, 8 H, Ph-H), 6.80 (s,

1 H, Ph-H), 6.97 (m, 8 H, Ph-H), 7.10 (s, 2 H, Ph-H), 7.15 [t, J =

7.3 Hz, 4 H, Ph-H (CZ)], 7.20 (s, 2 H, Ph-H), 7.35–7.45 [td, J =

7.0, J = 8.1 Hz, 8 H, Ph-H (CZ)], 7.48 [d, J = 7.7 Hz, 4 H, Ph-H

(OXZ)], 7.55 [d, J = 8.5 Hz, 4 H, Ph-H (OXZ)], 8.05 [m, 12 H,

Ph-H (OXZ), Ph-H (CZ)], 8.10 (2×s, 4 H, perylene-H) ppm. MS

(MALDI-TOF): m/z = 2197.9 [M⁺].

8CZ-(G-2)-PTCDI (12): A mixture of N,NЈ-bis(2-hydroxyethyl)-

1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis(dicarb-

oximide) (0.53 g, 0.63 mmol), compound 42 (2.3 g, 3.4 mmol), and

anhydrous potassium carbonate (1.5 g, 10.9 mmol) in anhydrous

DMF (40 mL) was stirred vigorously at 140 °C under argon for

24 h. After cooling to room temperature, the mixture was added to

H₂O (200 mL). The precipitate was filtered off and dried. The prod-

uct was purified by column chromatography on silica gel eluting

with CH₂Cl₂to give 12 as a dark-red solid (0.45 g, yield 21.0%).

M.p. 104–106 °C. ¹H NMR (500 MHz, CDCl₃, 25 °C): δ = 1.12 (d,

J = 6.2 Hz, 24 H, -CH₃), 1.78 (m, 16 H, -CH₂-), 2.03 (m, 16 H,

-CH₂-), 2.70 (m, 4 H, -CH-), 3.87 (t, J = 6.0 Hz, 16 H, -OCH₂-),

4.33 (t, J = 7.0 Hz, 16 H, -NCH₂-), 4.89 (s, 8 H, -OCH₂-), 6.31 (s,

4 H, Ph-H), 6.51 (s, 8 H, Ph-H), 6.88 (d, J = 9.0 Hz, 8 H, Ph-H),

6.94 (d, J = 9.0 Hz, 8 H, Ph-H), 7.21 [t, J = 7.3 Hz, 16 H, Ph-H

Preparation of Cascade Energy-Transfer Imide-Type Dendrimers

2CZ-2NP-(G-1)-PTCDI (10): A mixture of N,NЈ-bis(2-hydroxy- (CZ)], 7.27 (s, 4 H, Ph-H), 7.28 (s, 2 H, Ph-H), 7.38–7.48 [td, J =

ethyl)-1,6,7,12-tetrakis(4-methylphenoxy)-3,4:9,10-perylenebis-

(dicarboximide) (0.1 g, 0.11 mmol), compound 40 (0.2 g,

0.28 mmol), DCC (0.5 g, 2.4 mmol), and DMAP (0.2 g, 1.6 mmol)

in anhydrous CH₂Cl₂(30 mL) was stirred at room temperature for

7.5, J = 8.1 Hz, 32 H, Ph-H (CZ)], 8.08 [d, J = 7.7 Hz, 16 H,

Ph-H (CZ)], 8.18 (s, 4 H, perylene-H) ppm. ¹³C NMR (100 MHz,

CDCl₃): δ = 24.76, 26.51, 27.62, 29.80, 43.34, 68.26, 71.23, 101.63,

106.56, 109.36, 116.93, 119.54, 120.11, 120.67, 120.94, 121.06,

1000

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Eur. J. Org. Chem. 2006, 986–1001

Carrier-Transporting Dendrimers with a Luminescent Core

FULL PAPER

sky, U. M. Wiesler, T. Vosch, J. Hofkens, F. C. D. Schryver, K.

Müllen, Chem. Eur. J. 2001, 7, 4844–4853.

[22] J. Qu, N. G. Pschirer, D. Liu, A. Stefan, F. C. Schryver, K.

Müllen, Chem. Eur. J. 2004, 10, 528–537.

122.09, 123.43, 123.56, 124.57, 126.35, 139.86, 141.06, 146.38,

149.46, 156.59, 157.30, 160.98, 164.01 ppm. MS (MALDI-TOF):

m/z = 3425.4 [M⁺+ Na].

[23] P. Du, W. H. Zhu, Y. Q. Xie, F. Zhao, C. F. Ku, Y. Cao, C. P.

Chang, H. Tian, Macromolecules 2004, 37, 4387–4398.

[24] P. Furuta, J. M. J. Fréchet, J. Am. Chem. Soc. 2003, 125,

13173–13181.

[25] a) S. K. Grayson, J. M. J. Fréchet, Chem. Rev. 2001, 101, 3819–

3867; b) D. A. Tomalia, J. M. J. Fréchet, Prog. Polym. Sci.

2005, 30, 217–219; c) S. F. Li, G. Zhong, W. H. Zhu, F. Y. Li,

J. F. Pan, W. Huang, H. Tian, J. Mater. Chem. 2005, 15, 3221–

3228; d) S. A. Soomro, R. Benmouna, R. Berger, H. Meier, Eur.

J. Org. Chem. 2005, 3586–3593.

Acknowledgments

This study was partly supported by the Natural Science Foundation

of China, the Education Committee of Shanghai, and the Scientific

Committee of Shanghai. W. H. Z. thanks the Foundation for

National Excellent Dissertation of the P. R. China (project no.

200143).

[26] a) W. H. Zhu, Y. S. Xu, Y. Zhang, J. P. Shen, H. Tian, Bull.

Chem. Soc. Jpn. 2005, 78, 1362–1367; b) W. H. Zhu, M. Hu,

R. Yao, H. Tian, J. Photochem. Photobiol. A 2003, 154, 169–

177; c) W. H. Zhu, H. Tian, A. Elschner, Chem. Lett. 1999,

501–502; d) W. H. Zhu, C. Hu, K. C. Chen, H. Tian, Synth.

Met. 1998, 96, 151–154; e) H. Tian, W. H. Zhu, K. C. Chen,

Synth. Met. 1997, 91, 229–231.

[1] C. W. Tang, S. A. VanSlyke, Appl. Phys. Lett. 1987, 52, 913–

915.

[2] C. Devadoss, P. Bharathi, J. S. Moore, J. Am. Chem. Soc. 1996,

118, 9635–9644.

[3] T. W. Kwon, M. M. Alam, S. A. Jenekhe, Chem. Mater. 2004,

16, 4657–4666.

[4] U. Mitschke, P. Bäuerle, J. Mater. Chem. 2000, 10, 1471–1507.

[5] a) A. Kraft, A. C. Grimsdale, A. B. Holmes, Angew. Chem. Int.

Ed. 1998, 37, 402–428; b) D. Neher, Macromol. Rapid Com-

mun. 2001, 22, 1365–1385.

[6] C. T. Chen, Chem. Mater. 2004, 16, 4389–4400.

[7] X. Mi, Z. Q. Gao, M. W. Liu, K. Y. Chan, H. L. Kwong, N. B.

Wong, C. S. Lee, L. S. Hung, S. T. Lee, J. Mater. Chem. 2002,

12, 1307–1310.

[8] a) C. H. Chen, C. W. Tang, J. Shi, K. P. Klubek, Macromol.

Symp. 1997, 125, 49–58; b) C. H. Chen, C. W. Tang, J. Shi,

K. P. Klubek, Thin Solid Films 2000, 363, 327–331.

[9] X. H. Zhang, B. J. Chen, X. Q. Lin, Q. Y. Wong, C. S. Lee,

H. L. Kwong, S. T. Lee, S. K. Wu, Chem. Mater. 2001, 13,

1565–1569.

[27] a) A. Prodi, C. Chiorboli, F. Scandola, E. Iengo, E. Alessio,

R. Dobrawa, F. Würthner, J. Am. Chem. Soc. 2005, 127, 1454–

1462; b) E. H. A. Beckers, S. C. J. Meskers, A. P. H. J.

Schenning, Z. J. Chen, F. Würthner, R. A. J. Janssen, J. Phys.

Chem. A 2004, 108, 6933 –6937; c) J. S. Park, C. W. Lee, M. S.

Gong, Synth. Met. 2003, 132, 177–184; d) H. Tian, P. H. Liu,

W. H. Zhu, E. Q. Gao, D. J. Wu, S. M. Cai, J. Mater. Chem.

2000, 10, 2708–2715; e) K. Sugiyasu, N. Fujita, S. Shinkai, An-

gew. Chem. Int. Ed. 2004, 43, 1229–1233.

[28] C. J. Hawker, J. M. J. Fréchet, J. Am. Chem. Soc. 1990, 112,

7638–7647.

[29] a) J. S. Park, C. W. Lee, M. S. Gong, Synth. Met. 2003, 132,

177–184; b) F. Würthner, C. Thalacker, A. Sautter, Adv. Mater.

1999, 11, 754–758.

[10] H. Xin, F. Y. Li, M. Shi, Z. Q. Bian, C. H. Huang, J. Am.

Chem. Soc. 2003, 125, 7166–7167.

[11] J. Kido, Y. Okamoto, Chem. Rev. 2002, 102, 2357–2368.

[12] S. F. Li, G. Y. Zhong, W. H. Zhu, F. Y. Li, J. F. Pan, W. Huang,

H. Tian, Chem. Lett. 2005, 34, 688–689.

[30] J. March, Advanced Organic Chemistry, 3rd ed., John Wiley &

Sons, Inc., New York, 1985, p. 348.

[31] a) H. Doi, M. Kinoshita, K. Okumoto, Y. Shirota, Chem. Ma-

ter. 2003, 15, 1080–1089; b) M. S. Wong, Z. H. Li, Y. Tao, M.

D’Iorio, Chem. Mater. 2003, 15, 1198–1203.

[13] a) M. A. Baldo, D. F. O’Brien, Y. You, A. Shoustikov, S. Stib-

ley, M. E. Thompson, S. R. Forrest, Nature 1998, 395, 151–

154; b) D. F. O’Brien, M. A. Baldo, M. E. Thompson, S. R.

Forrest, Appl. Phys. Lett. 1999, 74, 442–444; c) M. D.

McGehee, T. Bergstedt, C. Zhang, A. P. Saab, M. B. O’Rega,

G. C. Bazan, V. I. Sradanov, A. J. Heeger, Adv. Mater. 1999, 11,

1349–1354.

[32] a) Y. J. Bing, L. M. Leung, G. Menglian, Tetrahedron Lett.

2004, 45, 6361–6363; b) Z. Liu, Y. G. Zhang, Y. F. Hu, G. P.

Su, D. G. Ma, L. X. Wang, X. B. Jing, F. S. Wang, J. Polym.

Sci., Part A: Polym. Chem. 2002, 40, 1122–1126; c) Y. G.

Zhang, Y. F. Hu, H. C. Li, L. X. Wang, X. B. Jing, F. S. Wang,

D. G. Ma, J. Mater. Chem. 2003, 13, 773–777.

[33] a) A. Sautter, B. K. Kaletas¸, D. G. Schmid, R. Dobrawa, M.

Zimine, G. Jung, I. H. M. van Stokkum, L. De Cola, R. M.

Williams, F. Würthner, J. Am. Chem. Soc. 2005, 127, 6719–

6729; b) J. M. Serin, D. W. Brousmiche, J. M. J. Fréchet, Chem.

Commun. 2002, 2605–2607; c) A. Adronov, P. R. L. Malenfant,

J. M. J. Fréchet, Chem. Mater. 2000, 12, 1463–1472; d) P. Fu-

ruta, J. Brooks, M. E. Thompson, J. M. J. Fréchet, J. Am.

Chem. Soc. 2003, 125, 13165–13172; e) S. L. Gilat, A. Adronov,

J. M. J. Fréchet, Angew. Chem. Int. Ed. 1999, 38, 1422–1427.

[34] K. R. Thomas, A. L. Thompson, A. V. Sivakumar, C. J.

Bardeen, S. Thayumanavan, J. Am. Chem. Soc. 2005, 127, 373–

383.

[14] K. R. J. Thomas, J. T. Lin, Y. T. Tao, C. H. Chuen, Adv. Mater.

2002, 14, 822–826.

[15] B. S. Li, J. Li, Y. Q. Fu, Z. S. Bo, J. Am. Chem. Soc. 2004, 126,

3430–3431.

[16] a) M. C. Daniel, D. Astruc, Chem. Rev. 2004, 104, 293–346; b)

G. R. Newkome, C. N. Moorefield, J. D. Epperson, Eur. J. Org.

Chem. 2003, 3666–3672; c) J. Ropponen, J. Tamminen, M. Lah-

tinen, J. Linnanto, K. Rissanen, E. Kolehmainen, Eur. J. Org.

Chem. 2005, 73–84.

[17] M. Kawa, J. M. J. Fréchet, Chem. Mater. 1998, 10, 286–296.

[18] P. W. Wang, Y. J. Liu, C. Devadoss, P. Bharathi, J. S. Moore,

Adv. Mater. 1996, 8, 237–241.

[35] B. Verheyde, W. Dehaen, J. Org. Chem. 2001, 66, 4062–4064.

[36] Z. H. Bo, W. K. Zhang, X. Zhang, C. M. Zhang, J. C. Shen,

Macromol. Chem. Phys. 1998, 199, 1323–1327.

[19] A. Freeman, J. Fréchet, S. Koene, M. Thompson, Macromol.

Symp. 2000, 154, 163–169.

[20] A. Kimoto, J. S. Cho, M. Higuchi, K. Yamamoto, Macromole-

cules 2004, 37, 5531–5537.

[21] a) J. Qu, J. Zhang, A. C. Grimsdale, K. Müllen, Macromole-

cules 2004, 37, 8297–8306; b) A. Herrmann, T. Weil, V. Siniger-

[37] Q. C. Wang, D. H. Qu, J. Ren, L. H. Xu, M. Y. Liu, H. Tian,

Dyes Pigm. 2003, 59, 163–171.

Received: August 24, 2005

Published Online: December 13, 2005

Eur. J. Org. Chem. 2006, 986–1001

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Synthesis of carrier-transporting dendrimers with perylenebis(dicarboximide)s as a luminescent core

DOI: 10.1002/ejoc.200500642

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