Synthesis and Analysis of Telechelic Polyisobutylenes for Hydrogen-Bonded Supramolecular Pseudo-Block Copolymers

Article abstract of DOI:10.1021/ma034924t

New telechelic polyisobutylenes (PIB) with hydrogen-bonding motifs were prepared. Nucleobases such as thymine, uracil, and cytosine as well as chelate-type hydrogen-bonding donor-acceptors were affixed onto the end groups of the PIB. Starting with PIB of

Full text of DOI:10.1021/ma034924t

Macromolecules 2004, 37, 1749-1759
1749
Synthesis and Analysis of Telechelic Polyisobutylenes for
Hydrogen-Bonded Supramolecular Pseudo-Block Copolymers
Wolfga n g H. Bin d er ,*,† Mich a el J . Ku n z,† Ch r istia n Klu ger ,† Getr a u d Ha yn ,‡ a n d
Rober t Sa f‡
Institute of Applied Synthetic Chemistry, Vienna University of Technology, Division of Macromolecular
Chemistry, Getreidemarkt 9/ 163/ MC, A-1060 Wien, Austria, and Graz University of Technology,
Institute for Chemistry and Technology of Organic Materials, Stremayrgasse 16, A-8010 Graz
Received J uly 2, 2003; Revised Manuscript Received December 18, 2003
ABSTRACT: New telechelic polyisobutylenes (PIB) with hydrogen-bonding motifs were prepared.
Nucleobases such as thymine, uracil, and cytosine as well as chelate-type hydrogen-bonding donor-
acceptors were affixed onto the end groups of the PIB. Starting with PIB of defined molecular weight,
prepared by living cationic polymerization, hydroxyterminated PIB was generated, which subsequently
was transformed into the corresponding chloromethyl ether. Reaction with silylated nucleobases furnished
the final nucleobase-telechelic PIB in high yields. The chelate-type PIB was prepared by a sequence of
nucleophilic/addition reaction steps adapted to the low solubility of PIB polymers in polar solvents. The
structure of the PIB polymers was proven by 1H NMR, 13C NMR, and MALDI-TOF MS analysis proving
the complete conversion between the reaction steps in quantitative yields. The pure PIB polymers with
specific hydrogen bonding patterns will allow the investigation of supramolecular pseudo-block copolymers.
In tr od u ction
philic substitution methods derived from the well-known
chemistry of nucleosides are adapted to this purpose.
Critical for the attachment of nucleobases (such as
thymine, uracil, cytosine, or adenine) is the site specific
and regiospecific substitution due to the presence of
more than one nucleophilic site at the respective nucleo-
base appropriate for substitution.
The use of intermolecular interactions to organize the
threedimensional structure of polymers has attracted
increased attention during the past few years.1 Directed
hydrogen bonds2 have shown equally effective in com-
parison to “conventional” intermolecular bonds such as
metal complexes,3 π-π stacking,4 and ionic forces,5 since
they allow the tuning of binding constants between
several 1 M-1 up to 106 M-1 by use of a specific
hydrogen-bond matching pair.6 Additionally the ability
to select specific intermolecular bonding combinations
within several possibilites7 (i.e.: favoring A-B contact
over A-A or B-B binding) is unique to hydrogen bonds,
thus offering new types of supramolecular arrange-
ments. When affixed properly to small molecules8 or
polymers,9 hydrogen bonds can induce new types of
ordering and organization within materials, leading to
supramolecular polymers.10 The positioning of hydrogen
bonds at specific positions within polymer chains can
generate tunable materials with new properties such
as thermoplastic behavior11 and controlled rheological
properties12 as well as controlled molecular architec-
tures.13
A necessary requirement for the investigation of this
type of materials is the controlled synthesis of telechelic
polymers with appropriately positioned hydrogen donor/
acceptor moieties. Several direct methods such as
ROMP,14 Ziegler-Natta,15 ATRP,16 anionic,17 and free
radical polymerizations18 as well as efficient postmodi-
fication methods19 can be combined to generate telech-
elics with hydrogen bonding substituents, defined chain
lengths and low polydispersities. The synthesis of tel-
echelic polymers with hydrogen-bonding motifs derived
from nucleobase structures has been described by a
variety of authors.17,19,20 Usually, conventional nucleo-
The present publication reports on the synthesis and
analysis of telechelic poly(isobutylenes) “PIB” with
defined hydrogen-bonding motifs at their chain ends
(Scheme 1). The combination between the living polym-
erization of polyisobutylene with hydrogen bonding
motifs is attractive due to two reasons: On one hand,
the quasi-living polymerization of PIB21 allows the exact
tailoring of telechelics with defined chain lengths, low
polydispersity, and defined functionalization21d due to
the absence of chain transfer- and termination reactions.
On the other hand, PIB polymers are extremely flexible,
low-Tg polymers, allowing the study of the influence of
hydrogen-bonding structures in mixtures with comple-
menting stiff-rod systems (such as the poly(ether ke-
tones) recently described in our group22). Thus, phase
separation effects in dependence of hydrogen-bonding
strength yielding pseudo-block copolymers can be stud-
ied impressively.22c Therefore, two types of PIB polymers
were prepared: telechelic PIB with a thymine (1a ),
uracil (1b), or cytosine (1c) residue reminiscent of
bonding patterns in DNA, as well as chelate-type
bonding structures with multiple hydrogen bonding
arrays 1d derived from Lehn et al.23 There is a stability
difference of more than 103 between the triple hydrogen
bonds in 1a -1c (Kassn is approximately 1000 M-1
)
compared to the multiple hydrogen bonds in 1d (Kassn
>106 M-1).
The quasi-living cationic polymerization of polyisobu-
tylene (PIB) is not compatible with the polar nature of
hydrogen bonds. Additionally, there is a limited solubil-
ity of PIB in a variety of solvents normally appropriate
for the nucleophilic displacement chemistry useful for
the introduction of nucleobases. Thus, two main points
† Vienna University of Technology.
‡ Graz University of Technology.
* To whom correspndence should be addressed. E-mail: wbinder@
mail.zserv.tuwien.ac.at.
10.1021/ma034924t CCC: $27.50 © 2004 American Chemical Society
Published on Web 02/10/2004

1750 Binder et al.
Macromolecules, Vol. 37, No. 5, 2004
Sch em e 1
hydride and distilled in vacuo before use. n-Hexane was
refluxed over concentrated H2SO4 for 48 h in order to remove
olefins. The organic layer was washed with distilled water,
dried with MgSO4 and stored over CaH2. It was distilled under
a dry Ar atmosphere before use. THF was freshly distilled from
potassium before use. CH2Cl2, CHCl3, C2H4Cl2, and methanol
were dried and distilled over CaH2 under dry argon. DMF was
dried and distilled over BaO under dry argon. Isobutylene was
dried by passing the gas through a column packed with
potassium hydroxide.
have been investigated within this publication: the
development of a protocol for the postmodification
reaction yielding the telechelic polymers 1a -1d as well
as efficient reaction pathways for the complete attach-
ment of nucleobase structures onto the PIB backbone
together with the analysis of the end groups via NMR
spectroscopy and MALDI.
Exp er im en ta l Section
Syn th eses of Allyl-Ter m in a ted P IB’s (2). A general
method for synthesis of allyl-terminated PIB’s is shown by the
synthesis of allyl-terminated PIB with Mn ) 2500 g mol-1
according to Ivan et al.21b,f Dichloromethane (160 mL), olefin-
free n-hexane (160 mL), DMA (1.96 mL), and DCCl (3.05 g,
10.61 mmol) were added to a 1 L three-necked flask equipped
with a septum, a mechanical stirrer, and a nitrogen inlet and
cooled to -80 °C. Condensated isobutylene (14 g, 250 mmol)
was charged into the reactor by a syringe. After 5 min of
stirring, a prechilled solution of TiCl4 (40.25 g, 212 mmol) and
2,6-di-tert-butylpyridine (0.2 mL) in methylenchloride (80 mL)
and olefin-free n-hexane (200 mL) was transferred to the
reactor by a transfer needle. The temperature was held at -80
°C during the whole polymerization procedure. After 10 min,
a second addition of isobutylene (9.82 g, 175 mmol) followed.
20 min later, the polymerization was terminated by the
addition of prechilled allyltrimethylsilane (6.7 g, 58.6 mmol).
After 30 min, the mixture was poured into a vigorously stirred
saturated aqueous NaHCO3 solution and filtered through
Hyflo. The organic layer was separated, washed 5 times with
distilled water, dried over MgSO4. The solvent was removed
by rotary evaporator. Then, the polymer was redissolved in a
small amount of n-hexane and precipitated 2 times into
acetone in order to remove excess allyltrimethylsilane. Finally
the colorless sticky polymer was dried under vacuum. Yield:
25.2 g (94%); 1H NMR (400 MHz, CDCl3): δ (ppm) 0.79 (s,
12H), 0.83-1.50 (m, 433H), 1.54 (s, 4H), 1.83 (s, 4H), 2.01 (d,
4H), 5.00 (t, 4H), 5.83 (m, 2H), 7.17 (s, 3H); 13C NMR (50 MHz,
CDCl3): δ(ppm) 28.70-31.60, 32.29, 34.75, 37.51-39.50, 50.29,
55.72, 58.00-60.00, 116.75, 120.06, 121.15, 136.08, 148.5,
148.93.
In str u m en ta tion . NMR spectra were obtained from a 200
MHz Bruker AC200 spectrometer, a 400 MHz Bruker Avance
DRX 400 and a 600 MHz Bruker DRX 600 in CDCl3 (liquid
NMR). GPC analysis was performed on a Hewlett-Packard
Chemstation 1100 system using Styragel linear columns in
THF at 40 °C. Polyisobutylene standards were used for
conventional external calibration using a Waters RI 2410
refractive index detector. DSC-measurements were done on a
Mettler DSC30 System TA4000. MALDI-TOF mass spectra
were performed on a Micromass TofSpec2E time-of-flight mass
spectrometer equipped with a nitrogen laser (λ ) 337 nm,
operated at 5 Hz) and a time-lag focusing unit. Ions were
generated by irradiation just above the threshold laser power.
The spectra were recorded in the reflectron mode with an
acceleration voltage of 20 kV and externally calibrated with a
suitable mixture of poly(ethylene glycol)s (PEG). Sample
solutions were prepared by mixing a solution of dithranol in
THF (c ) 10 mg/mL), a solution of the analyte (c ) 3 mg/mL),
and a solution of CF3COOAg (AgTFA, c ) 1 mg/mL) and
CF3COONa (NaTFA, c ) 1 mg/mL), respectively, in a ratio of
5:1:1 (v/v/v). Additionally, 5:1:1:0.1 dithranol-analyte-NaTFA-
AgTFA mixtures were applied, and 0.5 µL of the mixture was
deposited on the sample plate (stainless steel) and allowed to
dry under air. The spectra of 100-150 shots were averaged to
improve the signal-to-noise ratio.
Ma ter ia ls. All materials were obtained from Aldrich and
used without further purification if not mentioned otherwise.
2,6-Diaminopyridine was recrystallized from boiling chloro-
form. Silylated nucleobases were prepared according to Griengl
et al.24a 1-tert-Butyl-3,5-bis(1-chloro-1-methylethyl)benzene
(DCCl) was obtained according to Faust et al.21e N-(6-Ami-
nopyridine-2-yl)butyramide was obtained according to Lehn
et al.23 DMA (N,N-dimethylacetamide) was dried over calcium
Syn th eses of Hyd r oxy-Ter m in a ted P IB’s (6). A general
method for synthesis of hydroxy-terminated PIB’s is shown

Macromolecules, Vol. 37, No. 5, 2004
Telechelic Polyisobutylenes 1751
by the synthesis of hydroxyl-terminated PIB with Mn ) 2500
g mol-1 according to a modified protocol of Ivan et al.21c Allyl-
terminated PIB 2 (7.5 g, 3 mmol) was dissolved in THF (430
mL), freshly distilled over potassium. The solution was sparged
with argon for 5 min. A 0.5 M 9-BBN-solution in THF (75 mL,
37.5 mmol) was added dropwise under dry argon atmosphere
at room temperature. After 5 h of stirring the mixture was
cooled to 0 °C and methanol (2.1 mL) and m-chloroperoxyben-
zoic acid (47 g, 0.19 mol) were added carefully. The reaction
was allowed to react for 10-15 h, and then n-hexane (100 mL)
and distilled water (100 mL) were added. The aqueous phase
was saturated with potassium carbonate. The organic layer
was washed five times with 50% aqueous methanol and five
times with distilled water, separated, and dried with sodium
sulfate. After filtration the solvent was evaporated and the
product dried under vacuum at ambient temperature. Yield:
7.5 g (100%); 1H NMR (400 MHz, CDCl3): δ (ppm) 0.79 (s,
12H), 0.83-1.67 (m, 424H), 1.83 (s, 4H), 3.62 (t, 4H J ) 6.9
Hz), 7.17 (s, 3H). 13C NMR (50 MHz, CDCl3): δ (ppm) 27.75,
30.76-31.62, 32.28, 34.76, 37.81-38.93, 41.41, 55.57, 58.54-
59.50, 63.96, 120.06, 121.15, 148.5, 148.93.
quantitative conversion to 1-chloromethoxydodecane (4) was
proved by 1H NMR spectroscopy. After 15 min of flushing with
nitrogen, the reaction mixture was filtered into a 100 mL
round-bottom flask which contained the silylated thymine
(5.37 mmol). The clear solution was stirred for 3 h at room
temperature under nitrogen atmosphere. The volume of the
reaction mixture was reduced to 20 mL at the rotary evapora-
tor, 5 mL distilled water was added, and the reaction mixture
was stirred for 5 min to hydrolyze the product. Finally the
reaction mixture was evaporated to dryness and the raw
product purified by chromatography (SiO2, CHCl3:THF ) 60:
1). Yield: 1.6 g (92%). 1H NMR (400 MHz, CDCl3): δ (ppm)
0.86 (t, 3H J ) 6.8 Hz), 1.24 (s, 18H), 1.54 (m, 2H), 1.93 (s,
3H), 3.51 (t, 2H J ) 6.8 Hz), 5.12 (s, 2H), 7.14 (s, 1H), 9.36 (s,
1H). 13C NMR (50 MHz, CDCl3): δ (ppm) 12.20, 13.97, 22.53,
25.81, 29.20, 29.23, 29.42-29.47, 29.51, 31.76, 69.41, 76.14,
111.45, 138.80, 151.44, 164.51.
NMR Ch a r a cter iza tion of 1-Dod ecyloxym eth yl-1H-
p yr im id in e-2,4-d ion e (5b). 1H NMR (400 MHz, CDCl3): δ
(ppm) 0.87 (t, 3H J ) 6.4 Hz), 1.24 (s, 18H), 1.56 (m, 2H), 3.52
(t, 2H J ) 6.8 Hz), 5.15 (s, 2H), 5.77 (d, 1H J ) 7.7 Hz), 7.31
(d, 1H J ) 7.67 Hz), 9.28 (s, 1H). 13C NMR (50 MHz, CDCl3):
δ (ppm) 14.09, 22.65, 25.90, 29.29-29.61, 31.87, 69.76, 76.60,
103.08, 142.96, 151.07, 163.55.
Syn th eses of Telech elic P IB’s 1a )1c. A general method
for synthesis of nucleoside telechelic PIB’s is shown by the
synthesis of thymine-telechelic PIB 1a (Mn ) 2700 g mol-1).
Gaseous HCl was introduced as a slow stream for 1 h into a
cold (0-4 °C) mixture of PIB-OH (6) (1.1 g, 0.4 mmol),
paraformaldehyde (50 mg, 1.6 mmol), and dry calcium chloride
(2 g, 18 mmol) in dry 1,2-dichlorethane (50 mL), while
maintaining the internal temperature below 15 °C. The
quantitative conversion to PIB-OCH2Cl (polymer 7) was
NMR Ch a r a cter iza tion of 4-Am in o-1-d od ecyloxym -
1
eth yl-1H-p yr im id in -2-on e 5c. H NMR (400 MHz, CDCl3):
δ (ppm) 0.88 (t, 3H J ) 5.9 Hz), 1.25 (s, 18H), 1.55 (m, 2H),
3.53 (t, 2H J ) 6.4 Hz), 5.20 (s, 2H), 5.80 (d, 3H J ) 7.0 Hz),
7.39 (d, 1H J ) 7.0 Hz). 13C NMR (50 MHz, CDCl3): δ (ppm)
14.12, 22.68, 25.97, 29.36-29.65, 31.91, 69.71, 76.48, 95.13,
144.31, 156.04, 165.29.
1
proven by H NMR spectroscopy. After 15 min flushing with
nitrogen, the reaction mixture was filtered into a 100 mL
round-bottom flask which contained the silylated thymine (8
mmol). The clear solution was stirred for 3 h at room temper-
ature under an atmosphere of nitrogen. After being gently
evaporated to dryness, the reaction mixture was hydrolyzed
by heating in water (20 mL)/ethanol (20 mL) under reflux for
30 min and dried under vacuum again. To remove the excess
of thymine the crude product was suspended in dry chloroform,
filtered and evaporated to dryness. Pure 1a was afforded by
chromatography (SiO2, CHCl3:THF ) 8:1). Yield: 0.98 g (89%).
1H NMR (400 MHz, CDCl3): δ (ppm) 0.79 (s, 12H), 0.92-1.61
(m, 539H), 1.83 (s, 4H), 1.95 (s, 6H), 3.49 (t, 4H J ) 6.6 Hz),
5.12 (s, 4H), 7.13 (s, 2H), 7.17 (s, 3H), 8.05 (s, 2H). 13C NMR
(50 MHz, CDCl3): δ (ppm) 12.36, 24.43, 28.67-31.60, 32.26,
34.72, 37.75-38.92, 41.55, 55.57, 58.53-59.50, 70.52, 77.05,
111.57, 120.05, 121.14, 138.84, 148.48, 148.92, 151.10, 163.97.
NMR Ch a r a cter iza tion of P IB 1b. 1H NMR (400 MHz,
CDCl3): δ (ppm) 0.79 (s, 12H), 0.88-1.61 (m, 437H), 1.83 (s,
4H), 3.50 (t, 4H J ) 6.6 Hz), 5.15 (s, 4H), 5.78 (d, 2H J ) 7.8
Hz), 7.16 (s, 3H), 7.31 (d, 2H J ) 7.8 Hz), 8.3-9.0 (bs, 2H).
13C NMR (50 MHz, CDCl3): δ (ppm) 24.42, 27.93-31.62, 32.26,
34.73, 37.32-38.93, 41.57, 56.60, 58.57-59.50, 70.70, 77.19,
103.11, 120.04, 121.14, 142.99, 148.48, 148.94, 151.06, 163.56.
NMR Ch a r a cter iza tion of P IB 1c. 1H NMR (400 MHz,
CDCl3): δ (ppm) 0.79 (s, 12H), 0.90-1.60 (m, 419H), 1.83 (s,
4H), 3.51 (t, 4H J ) 6.1 Hz), 5.20 (s, 4H), 5.81 (bs, 6H), 7.17
(s, 3H), 7.41 (d, 2H J ) 6.8 Hz). 13C NMR (50 MHz, CDCl3):
δ (ppm) 24.51, 29.27-31.61, 32.25, 34.72, 37.25-38.92, 41.63,
55.62, 59.68-59.68, 70.50, 77.20, 95.52, 120.03, 121.12, 144.01,
148.47, 148.93, 156.34, 165.69.
NMR Ch a r a cter iza tion of 1-Ch lor om eth oxyd od eca n e
(4). H NMR (400 MHz, CDCl3): δ (ppm) 0.87 (t, 3H J ) 5.6
1
Hz), 1.25 (s, 18H), 1.60 (m, 2H), 3.66 (t, 2H J ) 6.7 Hz), 5.49
(s, 2H). 13C NMR (50 MHz, CDCl3): δ (ppm) 14.04, 22.65,
25.92, 28.88, 29.28, 29.33, 29.51-29.62, 31.89, 70.62, 83.25.
1,6-Bis[3,5-bis(m eth oxyca r bon yl)p h en oxy]h exa n e (10).
A mixture of 5-hydroxyisophthalic acid dimethyl ester (1.198
g, 5.7 mmol), 1,6-dibromohexane (8) (0.732 g, 3.0 mmol),
potassium carbonate (1.330 g, 9.6 mmol), and 18-crown-6
(0.220 g, 0.8 mmol) in dry THF (25 mL) was refluxed for 48 h.
The mixture was evaporated to dryness, dissolved in chloro-
form, and washed twice with water and once with brine. The
organic layer was dried with magnesium sulfate, filtered, and
evaporated to dryness. The crude product was purified by
chromatography (SiO2, hexane/ethyl acetate 6:1) in order to
afford pure 10. Yield: 1.182 g (78%). 1H NMR (200 MHz,
CDCl3): δ (ppm) 8.26 (s, 2H), 7.74 (s, 4H), 4.06 (t, 4H), 3.95
(s, 12H), 1.85 (m, 4H), 1.59 (m, 4H). 13C NMR (50 MHz,
CDCl3): δ (ppm) 166.2, 159.1, 131.6, 122.8, 119.7, 68.3, 52.4,
29.0, 25.7.
1,12-Bis[3,5-bis(m eth oxyca r bon yl)p h en oxy]d od eca n e
(11). Compound 11 was prepared analogous to product 10
using 1,12-dibromododecane (9) (0.656 g, 2.0 mmol) as starting
material. Yield: 1.006 g (85%). 1H NMR (200 MHz, CDCl3):
δ(ppm) 8.25 (s, 2H), 7.73 (s, 4H), 4.03 (t, 4H), 3.93 (s, 12H),
1.81 (m, 4H), 1.60-1.20 (m, 16H). 13C NMR (50 MHz, CDCl3):
δ (ppm) 166.2, 159.2, 131.6, 122.7, 119.8, 68.6, 52.4, 29.5, 29.3,
29.0, 25.9.
1,6-Bis[3,5-bis(car boxy)ph en oxy]h exan e (12). Tetraester
10 (0.750 g, 1.5 mmol) was suspended in methanol (20 mL)
and was heated to reflux. A solution of NaOH (0.216 g, 5.4
mmol) in water (1.3 mL) was added, and the solution was
stirred at that temperature for 12 h. The mixture was
evaporated to dryness, dissolved in water and treated with
concentrated HCl. The precipitate was collected by filtration,
washed twice with cold water and dried under vacuo to afford
NMR Ch a r a cter iza tion of P IB 7. 1H NMR (400 MHz,
CDCl3): δ (ppm) 0.79 (s, 12H), 0.95-1.50 (m, 426H), 1.83 (s,
4H), 3.65 (t, 4H J ) 6.6 Hz), 5.51 (s, 4H), 7.17 (s, 3H). 13C
NMR (50 MHz, CDCl3): δ (ppm) 23.92, 29.30-31.58, 32.23,
34.72, 37.72-38.90, 41.49, 55.54, 58.50-59.50, 71.53, 83.32,
120.03, 121.12, 148.47, 148.91.
Syn th eses of Mod el Com p ou n d s 5a )5c. A general
method for the synthesis of model compounds is shown by the
synthesis of 1-dodecyloxymethyl-5-methyl-1H-pyrimidine-2,4-
dione (5a ). Gaseous HCl was introduced as a slow stream for
1 h into a cold (0-4 °C) mixture of dodecane-1-ol (3) (1 g, 5.37
mmol), paraformaldehyde (0.18 mg, 5.9 mmol), and dry
calcium chloride (5 g, 45 mmol) in dry 1,2-dichlorethane (50
mL), maintaining the internal temperature below 15 °C. The
1
12. Yield: 0.588 (88%). H NMR (200 MHz, DMSO): δ (ppm)
8.10 (s, 2H), 7.66 (s, 4H), 4.12 (t, 4H), 1.81 (m, 4H), 1.54 (m,
4H). 13C NMR (50 MHz, DMSO): δ (ppm) 167.1, 159.0, 133.6,
122.5, 119.8, 68.3, 28.8, 25.5.
1,12-Bis[3,5-bis(ca r boxy)p h en oxy]d od eca n e (13). Com-
pound 13 was synthesized analogous to product 12 starting
with tetraester 11 (0.701 g, 1.19 mmol). Yield: 0.525 (83%).
1H NMR (200 MHz, DMSO): δ (ppm) 13.26 (s, 4H), 8.05 (s,

1752 Binder et al.
Macromolecules, Vol. 37, No. 5, 2004
2H), 7.61 (s, 4H), 4.04 (t, 4H), 1.71 (m, 4H), 1.39 (m, 4H), 1.24
(m, 16H). 13C NMR (50 MHz, DMSO): δ (ppm) 166.4, 158.7,
132.5, 122.0, 118.9, 68.0, 28.9, 28.6, 28.4, 25.35.
complished for PIB with Mn ) 10 000 (g mol-1), for which the
same reaction conditions can be applied as for Mn ) 3000 (g
mol-1). A solution of 2,6-diaminopyridine (0.872 g, 8 mmol) in
dry THF (150 mL) was prepared under argon atmosphere and
cooled to -78 °C. A 2.5 M solution of buthyllithium in hexane
(2.88 mL, 7.2 mmol) was added dropwise to this mixture and
was stirred for 20 min. A mixture of 18 (0.400 g, 0.04 mmol)
in dry THF was added slowly to the reaction, which was stirred
for another 8 h at a constant temperature of -78 °C. The
mixture was allowed to reach room temperature and was
stirred at that temperature for 10 h. A solution of 1 M aqueous
NaHCO3 (40 mL) was added in order to quench the reaction
and the mixture was distributed between chloroform and
water. The aqueous layer was extracted three times with
chloroform,and the combined organic layer was washed with
brine, dried over magnesium sulfate, filtrated, and evaporated
under vacuo. To obtain pure monoacylated PIB 19, the crude
product was precipitated twice from chlorofrom in methanol
to afford 19. Yield: 0.364 g (91%). 1H NMR (200 MHz,
CDCl3): δ (ppm) 8.76 (s, 4H), 7.89 (s, 2H), 7.68 (d, 8H), 7.57
(s, 4H), 7.45 (t, 4H), 7.18 (s, 3H), 6.25 (d, 4H), 4.51 (s, 8H),
3.93 (t, 4H), 1.83 (m, 4H), 1.55-0.83 (m, 1480H), 0.79 (s, 12H).
13C NMR (50 MHz, CDCl3): δ (ppm) 164.5, 159.8, 157.2, 149.8,
148.9, 148.5, 140.1, 136.1, 121.1, 120.0, 117.1, 104.8, 103.7,
69.4, 59.5-58.5, 55.5, 52.4, 41.5, 38.8-37.8, 34.8, 31.9-30.7,
29.4, 24.2, 14.2.
Bis[3,5-bis[6-(bu tyr yla m in o)p yr id in -2-yl-ca r ba m oyl]-
p h en oxy]-Ter m in a ted P IB (1d ). The presented synthesis
was accomplished for PIB with Mn ) 10 000 (g mol-1); the same
reaction conditions were applied for Mn ) 3000 (g mol-1). A
solution of 19 (0.36 g, 0.036 mmol) and triethylamine (0.85
mL, 6 mmol) in dry THF (40 mL) was cooled to 0 °C, and a
solution of butyryl chloride (0.32 mL, 3 mmol) in dry THF (5
mL) was added dropwise. The mixture was allowed to reach
room temperature, at which it was stirred for another 2 h. The
solvent was removed under high vacuo and the residue was
suspended in chloroform. The organic layer was washed twice
with a saturated NaHCO3 solution and once with brine, dried
over magnesium sulfate, filtered, and evaporated under
diminished pressure. The product was precipitated three times
from chloroform in methanol to afford pure title compound 1d .
Yield: 0.335 g (93%). 1H NMR (200 MHz, CDCl3): δ (ppm)
8.56 (s, 4H), 8.10-7.85 (m, 14H), 7.73 (t, 4H), 7.62 (s, 4H),
7.18 (s, 3H), 4.01 (t, 4H), 2.37 (t, 8H), 1.90-1.65 (m, 12H),
0.83-1.50 (m, 1560H), 0.79 (s, 12H). 13C NMR (50 MHz,
CDCl3): δ (ppm) 171.6, 164.3, 160.0, 149.7, 149.3, 148.9, 148.5,
140.9, 136.0, 121.1, 120.0, 117.1, 110.1, 109.6, 69.4, 59.5-58.5,
55.5, 52.4, 41.5, 38.8-37.8, 34.8, 31.9-30.7, 29.4, 24.2, 14.2.
1,6-Bis[3,5-bis[6-(bu tyr ylam in o)pyr idin -2-yl-car bam oyl]-
p h en oxy]h exa n e (14). Tetraacid 12 (0.230 g, 0.52 mmol) was
suspended in thionyl chloride (10 mL), and a drop of dry DMF
was added. The solution was heated to reflux and stirred for
18 h. The excess SOCl2 was distilled off at normal pressure,
and the residue was dried under high vacuum for 2 h. This
tetraacid chloride was used without any further purification.
The residue was dissolved in dry THF (2 mL) and injected into
a previously prepared solution of N-(6-aminopyridin-2-yl)-
butyramide (0.395 g, 2.20 mmol) and triethylamine (0.223 g,
2.20 mmol) in dry THF (10 mL) at 0 °C. The mixture was
heated to room temperature and stirred for 1 h after which
the solvent was removed under diminished pressure. The
residue was digested in water at 40 °C for 30 min; the crude
product was filtered and digested in methanol at 40 °C for
another 30 min in order to afford 14. Yield: 0.280 g (50%). 1H
NMR (400 MHz, DMSO): δ (ppm) 10.51 (s, 4H), 10.14 (s, 4H),
8.16 (s, 2H), 7.87 (m, 8H), 7.82 (t, 4H), 7.75 (s, 4H), 4.21 (t,
4H), 2.42 (t, 8H), 1.88 (m, 4H), 1.70-1.55 (m, 12H), 0.94 (t,
12H). 13C NMR (50 MHz, DMSO): δ (ppm) 172.4, 165.3, 159.0,
150.9, 150.4, 140.4, 135.9, 120.0, 117.5, 110.9, 110.3, 68.4, 38.3,
28.9, 25.6, 18.8, 13.9.
1,12-Bis[3,5-bis[6-(bu tyr yla m in o)p yr id in -2-yl-ca r ba m -
oyl]p h en oxy]d od eca n e (15). The synthesis was performed
analogously to that of product 14 using tetraacid 13 (0.500 g,
0.95 mmol) as the starting material. The crude product was
purified by chromatography (SiO2, chloroform/methanol 30:1)
in order to afford 15. Yield: 0.798 g (72%). 1H NMR (400 MHz,
DMSO): δ (ppm) 10.51 (s, 4H), 10.14 (s, 4H), 8.15 (s, 2H), 7.87
(m, 8H), 7.82 (t, 4H), 7.73 (s, 4H), 4.16 (t, 4H), 2.42 (t, 8H),
1.82 (m, 4H), 1.64 (m, 8H), 1.48 (m, 4H), 1.4-1.3 (m, 12H),
0.94 (t, 12H). 13C NMR (50 MHz, DMSO): δ (ppm) 171.9, 164.8,
158.6, 150.5, 150.0, 139.9, 133.5, 119.5, 117.1, 110.4, 109.9,
68.1, 38.0, 30.6, 29.0, 28.7, 28.5, 25.4, 18.3, 13.5.
Br om o-Ter m in a ted Telech elic P IB (17). The presented
synthesis was accomplished for PIB with Mn ) 10 000 (g
mol-1), for which the same reaction conditions can be applied
as for Mn ) 3000 (g mol-1). To a mixture of hydroxy-terminated
PIB 16 (9.33 g, 0.93 mmol) and CBr4 (3.56 g, 10.73 mmol) in
dry CH2Cl2 (250 mL) was added dropwise a solution of
triphenylphosphine (2.45 g, 9.33 mmol) in dry CH2Cl2 (10 mL)
at 0 °C. The mixture was allowed to reach room temperature
and was stirred for 12 h. The solvent was completely removed
under vacuo, suspended in hexane, and filtered. The solvent
was removed again, and the crude product was purified by
chromatography (SiO2, hexane/ethyl acetate 50:1) to afford 17.
Yield: 8.79 g (94%). 1H NMR (200 MHz, CDCl3): δ (ppm) 7.17
(s, 3H), 3.37 (t, 4H), 1.83 (m, 4H), 0.83-1.50 (m, 1580H), 0.79
(s, 12H). 13C NMR (50 MHz, CDCl3): δ(ppm) 149.0, 148.5,
58.5-59.5, 55.7, 44.1, 38.8-37.8, 34.9, 32.3, 31.9-30.7, 29.1,
28.1, 24.2.
Resu lts a n d Discu ssion .
Syn th esis of P IB Telech elics w ith Nu cleoba se
Moieties. The synthesis of polymers 1a -1c starts with
the corresponding telechelic hydroxyterminated PIB-
OH (2) (Mn ) 2500 (PD ) 1.17)), prepared by cationic
polymerization according to ref 21c) (Scheme 2). Initial
attempts to use direct nucleophilic substitution reac-
tions with silylated nucleobases (Vorbru¨ggen method24
on halo-terminated PIB) were not successful because of
the limited solubility of PIB in dipolar aprotic solvents.
We therefore changed our synthetic strategy to the more
activated chloromethyl ethers which are more prone to
nucleophilic reactivity toward nucleobases such as
thymine, uracil, and cytosine.25 This strategy was tested
using short chain models with alkyl moieties instead of
PIB moieties (Scheme 2a). The transformation from the
alcohol 3 into the chloromethyl ether 4 went cleanly in
a variety of solvents including dichloromethane, chlo-
roform and 1,2-dichloroethane by use of paraformalde-
hyde (trioxane). Critical for the avoidance of side
reaction was to keep the temperature below 15 °C under
a permanent stream of dry hydrogen chloride. The
reaction was checked permanently by 1H NMR spec-
Bis[3,5-bis(m eth oxycar bon yl)ph en oxy]-Ter m in ated P IB
(18). The presented synthesis was accomplished for PIB with
Mn ) 10 000 (g mol-1), same reaction conditions can be applied
for Mn ) 3000 (g mol-1). A mixture of bromo-terminated PIB
17 (4.82 g, 0.48 mmol), potassium carbonate (1.18 g, 8.68
mmol), 18-crown-6 (0.50 g, 1.89 mmol), and 5-hydroxyisoph-
thalic acid dimethylester (2.03 g, 9.64 mmol) in dry THF (150
mL) was stirred under reflux for 3 d. THF was removed under
low pressure, and the residue was suspended in hexane. The
organic layer was washed twice with water and once with
brine, dried over magnesium sulfate, filtered, and dried in
vacuo. The crude product was purified by chromatography
(SiO2, hexane/ethyl acetate 40:1) in order to afford 18. Yield:
4.09 g (85%). 1H NMR (200 MHz, CDCl3): δ (ppm) 8.27 (s, 2H),
7.74 (s, 4H), 7.17 (s, 3H), 4.01 (t, 4H), 3.94 (s, 12H), 1.83 (m,
4H), 0.83-1.50 (m, 1530H), 0.79 (s, 12H). 13C NMR (50 MHz,
CDCl3): δ (ppm) 166.2, 159.2, 148.9, 148.5, 131.7, 122.8, 121.2,
120.1, 119.8, 69.4, 59.5-58.5, 55.5, 52.4, 41.5, 38.8-37.8, 34.8,
32.3, 31.9-30.7, 29.4, 24.2.
Bis[3,5-bis[6-a m in op yr id in -2-yl-ca r ba m oyl]p h en oxy]-
Ter m in a t ed P IB (19). The presented synthesis was ac-

Macromolecules, Vol. 37, No. 5, 2004
Telechelic Polyisobutylenes 1753
F igu r e 1. 13C NMR spectra of polymers 7, 1a , 1b, and 1c.
Sch em e 2
troscopy and found to be complete after 60 min. Shorter
reaction times lead to the formation of side products,
in particular the methylene-1,1-bis(alkyl ether) visible
via resonances at 4.65 ppm (singlet, O-CH2-O moiety)
and 3.50 ppm (triplet, CH2-O-CH2-O-CH2- moi-
ety).26 After evaporation of the solvent, the final chlo-
romethyl ether 4 was obtained in quantitative yield.
This can be transformed into the respective nucleobase-
terminal methyl ethers by direct reactions with silylated
nucleobases in 1,2-dichloroethane as solvent in quan-
titative yield. After quenching of the reaction with water
(to destroy the excess of silylated nucleobase) and
purification by chromatography over silica (which re-
moves the excess nucleobase) the final products 5a -5c
are obtained in yields above 90%.
hyde in dry dichloroethane and gaseous HCl. PIB-OH
was obtained by a modified procedure from Ivan et al.21c
via a hydroboration/oxidation strategy from the PIB-
allyl 2. To achieve homogeneous reaction conditions, we
changed to m-chloroperoxybenoic acid instead of hydro-
gen peroxide as oxidant. During the formation of the
chloromethyl ether 7 a reaction temperature below 15
°C and a permanent check of the reaction progress by
NMR spectroscopy is required. The side reaction toward
a bridged (or cyclic) methylene-1,1-bis(alkyl ether) was
not observed by NMR spectroscopy, presumably due to
the low concentration of the CH2-OH end group.
Subsequent reaction of the PIB-chloromethyl ether 7
with silylated nucleobases furnishes the final telechelic
PIB 1a -1c after column-chromatography in quantita-
tive yield. The transformation efficiency is quantitative
The reaction worked equally well when applied to
PIB: thus the PIB-chloromethyl ether 7 was prepared
directly by reaction of PIB-OH (6) with paraformalde-
1
as judged via H and 13C NMR spectroscopy as shown
in Figures 1 and 2. The chemical structure of the end

1754 Binder et al.
Macromolecules, Vol. 37, No. 5, 2004
F igu r e 2. 1H NMR spectra of polymers 7, 1a , 1b, and 1c.
Ta ble 1. Molecu la r Weigh ts a n d Molecu la r Weigh t Distr ibu tion s of P IB P olym er s
entry
polymer
Mn(theor)
Mn(GPC)
Mw/Mn(GPC)
Mn(MALDI)
Mw/Mn(MALDI)
1
2
3
4
1a
1b
1c
1d
2700
2850
2700
3000
10 000
2500
2760
3200
2850
3720
10 300
2650
1.17
1.14
1.14
1.22
1.19
1.17
1.15
1.2
1.20
1.17
1.23
1.15
2189
2483
2207
3539
n.d.a
2048
1994
n.d.
n.d.
n.d.
3315
n.d.
1.11
1.05
1.08
1.03
n.d.
1.11
1.09
n.d.
n.d.
n.d.
1.04
n.d.
5
6
7
8
9
2
6
16
17
18
19
2500
2760
10 000
10 000
10 000
3000
10 100
10 100
10 800
3740
10
10 000
10 200
a
n.d.: not determined.
groups can be assigned in the corresponding spectra
clearly due to the presence of the nucleobase resonances.
A critical point in this reaction is the molecular weight of
the PIB: whereas, with molecular weights up to 3000 Da,
the solubility of PIB in 1,2-dichloroethane is sufficient
to promote the reaction between the chloromethyl ether
7 and the silylated nucleobase, at higher molecular
weights (above 10 000), the solubility of PIB in the sol-
vent is insufficient to achieve a complete reaction. Thus,
this method proceeds well with low molecular weight
PIB, but not with high molecular PIB. The use of alter-
native solvents (such as dichloromethane, chloroform,
or tetrahydrofuran) did not lead to improved results.
Syn th esis of P IB-Telech elics w ith Mu ltip le Hy-
d r ogen -Bon d in g Moieties. Fixation of multiple hy-
drogen bonds onto the PIB is attractive, since the
binding constant of this moiety is a factor 103 M-1
higher than those of the nucleobase moieties. This
hydrogen bonding motive resembles those of a cleft and
was introduced by Lehn et al.23 representing strong
binding toward barbituric acid and cyanuric acid de-
rivatives. Initially we have investigated the synthesis
of alkyl-type model systems in order to optimize the
synthetic strategy to achieve 100% transformation ef-
ficiencies within nonpolymeric substrates (Scheme 3a).
Thus, 1,6-dibromohexane (8) and 1,12-dibromododecane
(9) were used as starting points of the nucleophilic
substitution reaction with 5-hydroxyisophthalic acid
dimethyl ester yielding the corresponding esters 10 and
11. Dipolar aprotic solvents (such as N,N-dimethylfor-
mamide23), which are conventionally used for this type
of reaction had to be avoided due to the poor solubility
of PIB within these type of solvents. Instead, after
optimization, the combination of K2CO3/18-crown-6 in
tetrahydrofuran (THF) was successful in achieving a
complete conversion without side reaction such as
elimination reactions. Cleavage of the ester groups
yielded the tetraacids 12 and 13, which were readily
converted into the corresponding tetraacid chlorides
using thionyl chloride reaction with N-(6-aminopyridin-
2-yl)butyramide and triethylamine23 yielded the title
compounds 14 and 15.
The synthesis of the chelate-type PIB 1d starts from
the corresponding PIB-OH 16 (Mn ) 10 100 (PD ) 1.20)
as well as a PIB with Mn ) 3000 (PD ) 1.22)which is
converted to the dibromide PIB-Br 17 in quantitative
27
yield using triphenylphosphine/CBr4 (Scheme 3b).
Analogous to the small molecular alkyl derivative 12
this can be quantitatively substituted with 5-hydroxy-
isophthalic acid dimethyl ester by a SN2-type nucleo-
philic reaction in the presence of 18-crown-6 in tetrahy-
drofuran yielding the PIB-ester 18. Reaction of the
PIB-tetraester 18 with butyllithium/2,6-diaminopyri-
dine furnishes PIB 19, which can be transformed into

Macromolecules, Vol. 37, No. 5, 2004
Telechelic Polyisobutylenes 1755
Sch em e 3
the final chelate-type PIB 1d by reaction with butyryl
chloride in THF. The reactions steps proceed with yields
above 95%, which is the detection limit of 1H NMR
spectroscopy for the higher molecular weight polymers
(Figure 3).
lithium favored the exchange reaction and thus the
dimerization of the PIB chains. Experiments to verify
these results via MALDI-TOF MS failed until this
point, probably due to the low concentration. However,
the side reaction could be diminished by use of a
moderate excess of 2,6-diaminopyridine over butyl-
lithium together with high dilution conditions of the
reaction medium.
Str u ctu r a l An a lysis by MALDI)TOF MS. Se-
lected samples of the nucleoside telechelic PIB’s 1a -
1c and the chelate-type PIB 1d as well as the corre-
sponding precursors 2, 6, and 19 were investigated by
means of MALDI-TOF MS. Generally, it has to be
mentioned that a rather strong influence of the end
groups of the PIB’s on the ionization behavior was
observed. For polymers 2 and 6 the best spectra were
obtained by ionization with silver ions (matrix: dithra-
nol/AgTFA). The structure of the telechelic PIB’s 1a and
A critical point within the synthetic pathway con-
cerned the transformation of the PIB-phthalate 18 into
the amine 19 via the lithiated 2,6-diaminopyridine. By
use of very high excess of the nucleophilic reagents,
dimerization into bridged PIB derivatives in the amount
of approximately 15% was observed (Scheme 4). The
formation of the dimerization product was proven by
GPC-analysis clearly showing the product with the
doubled molecular weight. This can be explained by an
exchange reaction between the monolithium salt of 2,6-
diaminopyridine with the already formed product 19.
Since the pKa values of the amino groups are compa-
rable, the high excess of 2,6-diaminopyridine/butyl-

1756 Binder et al.
Macromolecules, Vol. 37, No. 5, 2004
F igu r e 3. 1H NMR (b) and 13C NMR spectra (a) of polymer 1d .
1b could be verified using dithranol/AgTFA/NaTFA as
matrix (Figure 4). Both spectra show the expected ions
[M‚Ag]+ and [M‚Na]+, respectively. In contrast to these
results, an unusual behavior of the two polymers was
detected when dithranol/AgTFA was applied. Figure 5
gives an expanded view of a corresponding spectrum of
polymer 1a . The spectrum shows only one important
series of ions which were separated by 56 Da, the mass
of the repeating unit. However, the m/z values of the
observed signals do not correspond to pseudo-molecular
ions [M‚Ag]+ that were expected due to the addition of
AgTFA. For example, polymer 1a with a degree of
polymerization n of 28 ionized by attachment of Ag+
would have a monoisotopic mass of 2287.0 Da, a value
where no significant signal was detected. Ionization of
polymer 1a with protons or sodium ions would lead to
ions [M‚H]+ and [M‚Na]+, respectively, that have dif-
ferent masses too. It is important to note that compa-
rable results were obtained for polymer 1b when
investigated from dithranol/AgTFA (Figure 5). Again the
observed signals could not be assigned to simple pseudo-
molecular ions like [M‚Ag]+. But it is important to note
that a mass difference of 28 Da was observed between
corresponding signals in the two spectra of polymer 1a
and 1b, respectively. This difference has to be observed
due to the additional CH3 groups of the thymine end
groups of polymer 1a in comparison to the uracile end
groups of polymer 1b. Consequently, an unusual be-
havior during the MALDI process was considered. On
the basis of the observed isotope pattern, and the results
of exact mass measurements where silver clusters
(compare Figure 5) were used for internal calibration,
the signals observed in these MALDI spectra of the
polymers 1a and 1b are interpreted as ions containing
three silver atoms. Assuming replacement of the acidic
CO-NH-CO protons of the thymine or uracile groups
by silver ionsse.g., during the sample preparation for
MALDI or during the irradiation with laser lightsand

Macromolecules, Vol. 37, No. 5, 2004
Telechelic Polyisobutylenes 1757
F igu r e 4. MALDI-TOF mass spectra of the telechelic PIB’s 1a , 1b (matrix, dithranol/NaTFA/AgTFA; major series, [M‚Ag]+;
minor series, [M‚Na]+), and 1c, 1d (matrix, dithranol/NaTFA; ions, [M‚Na]+).
Sch em e 4
subsequent ionization with an additional Ag+ would
lead to singly charged ions having masses that agree
to the measured signals with errors <15 ppm. For
example, a species [C130H240N4O6Ag2‚Ag]+ could be
formed via this way from polymer 1a with n ) 24. The
theoretical m/z value of the most intense peak of the
isotope distribution of this species is 2278.579 Da, a
value that agrees excellently with the signal at 2278.606
(Figure 5a). The interpretation is also supported by the
observation, that this unusual behavior was not ob-
served for polymer 1c, a product with a very similar
chemical structure of the end groups but without acidic
protons. Furthermore, reduction of the silver concentra-
tion and simultaneous addition of NaTFA lead to
suppression of the phenomenon as already shown with
the spectra in Figure 4.
Ionization with sodium ions (matrix: dithranol/
NaTFA) was found to be preferable for the products 1c,
1d and 19. The MALDI spectra of the polymers 1c and
1d (Figure 4) showed the expected ions [M‚Na]+.
The number-average molecular weights Mn and poly-
dispersities PD (PD ) Mw/Mn) calculated from the

1758 Binder et al.
Macromolecules, Vol. 37, No. 5, 2004
MALDI-TOF mass spectra of polymers 1a , 1b, 1c, 1d , 2, 6,
and 19, and DSC traces of polymers 1a , 1b, 1c, and 6 as well
as GPC traces of polymers 1a , 1b, 1c, 1d , 6, and 17 and a
comparision of GPC traces. This material is available free of
charge via the Internet at http://pubs.acs.org.
Refer en ces a n d Notes
(1) Ikkala, O.; ten Brinke, G. Science 2002, 295, 2407-2409.
(2) (a) Ky Hirschberg, J .; Brunsveld, L.; Ramzi, A.; Vekemans,
J . A. J .; Sijbesma, R. P.; Meijer, E. W. Nature (London) 2000,
38, 2870-2872. (b) Sartorius, J .; Schneider, H.-J . Chem.s
Eur. J . 1996, 11, 1446-1452.
(3) Schubert, U. S.; Eschbaumer, C. Angew. Chem., Int. Ed. Engl.
2002, 41, 2892-2926.
(4) Meyer, E.; Castellano, R. K.; Diederich, F. Angew. Chem., Int.
Ed. Engl. 2003, 42, 1210-1250.
(5) Bergbreiter, D. E. Angew. Chem., Int. Ed. 1999, 38, 2870-
2872.
F igu r e 5. Expanded view of the MALDI-TOF mass spectra
of the polymers 1a and 1b (matrix, dithranol/AgTFA; ions, [(M
- 2H + 2Ag)‚Ag]+; for discussion see text).
(6) Sherrington, D. C.; Taskinen, K. A. Chem. Soc. Rev. 2001,
30, 83-93.
(7) Paleos, C.; Tsiourvas, D. Adv. Mater. 1997, 9, 695-710.
(8) Prins, L. J .; Reinhoudt, D. N.; Timmermann, P. Angew. Chem.
2001, 113, 2446-2492.
(9) (a) Mu¨ller, M.; Seidel, U.; Stadler, R. Polymer 1995, 36, 3143-
3150. (b) Ky Hirschberg, J . H. K.; Ramzi, A.; Sijbesma, R.
P.; Meijer, E. W. Macromolecules 2003, 36, 1429-1432.
(10) Brunsveld, L.; Folmer, B. J . B.; Meijer, E. W. MRS Bull. 2000,
49-53.
MALDI spectra correlated systematically with the
results obtained by GPC (Table 1). In all cases the
values of Mn calculated from the MALDI spectra were
approximately 500-700 Da lower than those obtained
by GPC. Possible reasons are for example the fact that
the GPC was calibrated with polyisobutylene standards
that do not contain the rigid central aromatic segment
of the PIB’s investigated in this work and the fact that
the different end groups will have a significant influence
on the hydrodynamic volumes too, especially since the
molecular weight range of the products investigated
here was only a few kilodaltons. Furthermore, it is well-
known that mass discrimination during MALDI experi-
ments can lead to somewhat lower values of Mn.
Analysis of MALDI spectra that were acquired in the
linear mode gave values of Mn that were approximately
100 Da higher than the reflectron data presented in
Table 1.
However, the MALDI results obtained for different
PIB’s which were prepared from the same batch cor-
related satisfactory. For example, PIB-chelate 1d
(Mn,MALDI ) 3539) was synthesized from polymer 19
(Mn,MALDI ) 3315) (compare Scheme 3b). Thus, an
increase of Mn of 224 Da was detected. The deviation
from the theoretically predicted increase (280 Da) is
acceptable.
(11) (a) Stadler, R. Kautschuk Kunstoff Gummi 1993, 46, 619-
628. (b) Mu¨ller, M.; Dardin, A.; Seidel, U.; Balsamo, V.; Ivan,
B.; Spiess, H. W.; Stadler, R. Macromolecules, 1996, 29,
2577-2583.
(12) Lange, R. F. M.; van Gurp, M.; Meijer, E. W. J . Polym. Sci.,
Part A: Polym. Chem. 1999, 37, 3657-3670.
(13) Lehn, J .-M.; Fouquey, C.; Levelut, A.-M. Adv. Mater. 1990,
2, 254-257.
(14) Stubbs, L. P.; Weck, M. Chem.sEur. J . 2003, 9, 992-999.
Bazzi, H. S.; Sleimann, H. F. J . Am. Chem. Soc. 2002, 35,
9617-9620.
(15) Rieth, L. R.; Eaton, R. F.; Coates, G. W. Angew. Chem. 2001,
113, 2211-2214.
(16) Yamauchi, K.; Long, T. E. Polym. Prepr. 2002, 43 (1), 698-
699.
(17) Marsh, A.; Khan, A.; Haddleton, D. M.; Hannon, M. J .
Macromolecules 1999, 32, 8725-8731.
(18) Asanuma, H.; Ban, T.; Gotoh, S.; Hishiya, T.; Komiyama, M.
Macromolecules 1998, 31, 371-377.
(19) (a) Yamauchi, K.; Lizotte, J . R.; Long, T. E. Macromolecules
2003, 36, 1083-1088. (b) Deans, R.; Ilhan, F.; Rotello, V. M.
Macromolecules 1999, 32, 4956-4960. (c) Farnik, D.; Kluger,
C.; Kunz, M.; Machl, D.; Petraru, L.; Binder, W. H. Macromol.
Symp. 2004, in press.
(20) (a) Bazzi, H. S.; Sleiman, H. F. Macromolecules 2002, 35,
9617-9620. (b) Stubbs, L. P.; Weck, M. Chem.sEur. J . 2003,
9, 992-999. (c) Drechsler, U.; Thibault, R. J .; Rotello, V. M.
Macromolecules 2002, 35, 9621-9623. (d) Ilhan, F.; Gray, M.;
Rotello, V. M. Macromolecules 2001, 34, 2597-2601. (e) Ilhan,
F.; Boal, A. K.; Rotello, V. M. Polym. Prepr. 2000, 41 (2),
1348-1349. (f) Asanuma, H.; Ban, T.; Gotoh, S.; Hishiya, T.;
Komiyama, M. Macromolecules 1998, 31, 371-377. (g) Lind-
sell, W. E.; Murray, C.; Preston, P. N.; Woodman, A. J .
Tetrahedron 2000, 56, 1233-1245.
(21) (a) Puskas, J . E.; Kaszas, G. Prog. Polym. Sci. 2000, 25, 403-
452. (b) Ivan, B.; Kennedy, J . P. J . Polym. Sci., Polmy. Chem.
Ed. 1990, 28, 89-104. (c) Ivan, B.; Kennedy, J . P.; Chiang,
V. S. C. J . Polym. Sci., Polmy. Chem. Ed. 1980, 18, 3177-
3191. (d) Mishra, M. K.; Kennedy, J . P. In Desk Reference
Functional Polymers; American Chemical Society: Washing-
ton, DC, 1997; pp 57-72. (e) Gyor, M.; Wang, H. C.; Faust,
R. J . Macromol. Sci.sPure Appl. Chem. 1992, 29, 639-653.
(f) Feldthusen, J .; Ivan, B.; Mu¨ller, A. H. E.; Macromolecules
1998, 31, 578-585.
(22) (a) Kunz, M. J .; Machl, D.; Binder, W. H. Polym. Prepr. 2002,
43 (2), 410-411. (b) Kunz, M. J .; Hayn, G.; Saf, R.; Binder,
W. H. J . Polym. Sci., Part A: Chem. 2004, 661-674. (c)
Binder, W. H.; Kunz, M. J .; Ingolic, E. J . Polym. Sci.: Part
A: Chem. 2004, 162-172.
Con clu sion
We have demonstrated two highly efficient synthetic
pathways for the preparation of telechelic hydrogen-
bonded polyisobutylenes. Starting from hydroxy-tele-
chelic polyisobutylenes (PIB-OH, 3) the nucleoside
telechelic PIB’s 1a -1c as well as the chelate-type PIB
1d , with a multiple binding hydrogen motive, were
prepared in quantitative yields and high efficiency. The
identities of the products were characterized via 1H
NMR and 13C NMR spectroscopy as well as MALDI.
Altogether the synthesis of the telechelic PIB’s 1a -1d
demonstrates an excellent tool for the construction of
supramolecular polymers opening way to pseudo-block
copolymers as described in a forthcoming publication.22c
Ack n ow led gm en t. We thank the Austrian Science
Fund (FWF, Projects 14844-CHE and 13962-CHE) for
financial support. Dr. H. P. Ka¨hlig is thanked for
(23) (a) Berl, V.; Schmutz, M.; Krische, M. J .; Khoury, R. G.; Lehn,
J .-M. Chem.sEur. J . 2002, 8, 1227-1244. (b) Berl, V.;
Krische, M. J .; Huc, I.; Lehn, J . M.; Schmutz, M. Chem.s
Eur. J . 2000, 6, 1938-1946. (c) Berl, V.; Huc, I.; Lehn, J . M.;
DeCian, A.; Fischer, J . Eur. J . Org. Chem.. 1999, 3089-3094.
1
providing a 600 MHz H NMR instrument.
Su p p or tin g In for m a tion Ava ila ble: Figures showing
NMR spectra of polymers 1a , 1b, 1c, 1d , 6, 7, 17, 18, and 19,

Macromolecules, Vol. 37, No. 5, 2004
Telechelic Polyisobutylenes 1759
(d) Chang, S. K.; Hamilton, A. D. J . Am. Chem. Soc. 1988,
110, 1318-1319.
(26) Gazizova, L. B.; Imashev, U. B.; Musavirov, R. S.; Kantor,
E. A.; Zlotskii, S. S. J . Org. Chem. USSR 1981, 226-231.
(24) (a) Griengl, H.; Hyden, W.; Schindler, E.; Wanek, E. Arch.
Pharm. 1983, 316, 146-153. (b) Vorbru¨ggen, H.; Ha¨fle, G.
Angew. Chem. 1972, 347-349.
(27) Hamilton, G. S.; Wu, Y.-Q.; Limburg, D. C.; Wilkinson, D.
E.; Vaal, M. J .; Li, J .-H.; Thomas, C.; Huang, W.; Sauer, H.;
Ross, D. T.; Soni, R.; Chen, Y.; Guo, H.; Howorth, P.;
Valentine, H.; Liang, S.; Spicer, D.; Fuller, M.; Steiner, J . P.
J . Med. Chem. 2002, 45, 3549-3557.
(25) (a) Warshawsky, A.; Deshe, A. J . Polym. Sci. 1985, 23, 1839-
1841. (b) Danle, K.; Larsen, E.; Pedersen, E. B.; Vestergaard,
B. F.; Nielsen, C. J . Med. Chem. 1996, 39, 2427-2431. (c)
Benhilda, R.; Aubertin, A.-M.; Grierson, D. S.; Monneret, C.
Tetrahedron Lett. 1996, 37, 1031-1034.
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