Synthesis and structural analysis of some podands with C 3 symmetry

Article abstract of DOI:10.1080/00397911.2011.585732

The multistep syntheses of C₃-symmetrical tripodands with terminal triple bonds or azide groups exhibiting 1,3,5-triarylbenzene and 2,4,6-triaryl-1,3,5-triazine cores are reported herein. The structures of the newly synthesized compounds are su

Full text of DOI:10.1080/00397911.2011.585732

This article was downloaded by: [Georgetown University]
On: 21 August 2013, At: 00:46
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered
office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthetic Communications: An
International Journal for Rapid
Communication of Synthetic Organic
Chemistry
Publication details, including instructions for authors and
subscription information:
http://www.tandfonline.com/loi/lsyc20
Synthesis and Structural Analysis of
Some Podands with C3 Symmetry
Adrian Woiczechowski-Pop a , Ioana L. Dobra a , Gheorghe D. Roiban
a , Anamaria Terec a & Ion Grosu a
a Organic Chemistry Department, Faculty of Chemistry and Chemical
Engineering, Babeş Bolyai University, Cluj-Napoca, Romania
Accepted author version posted online: 20 Jan 2012.Published
online: 20 Aug 2012.
To cite this article: Adrian Woiczechowski-Pop , Ioana L. Dobra , Gheorghe D. Roiban , Anamaria
Terec & Ion Grosu (2012) Synthesis and Structural Analysis of Some Podands with C3 Symmetry,
Synthetic Communications: An International Journal for Rapid Communication of Synthetic Organic
Chemistry, 42:24, 3579-3588, DOI: 10.1080/00397911.2011.585732
To link to this article: http://dx.doi.org/10.1080/00397911.2011.585732
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the
“Content”) contained in the publications on our platform. However, Taylor & Francis,
our agents, and our licensors make no representations or warranties whatsoever as to
the accuracy, completeness, or suitability for any purpose of the Content. Any opinions
and views expressed in this publication are the opinions and views of the authors,
and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content
should not be relied upon and should be independently verified with primary sources
of information. Taylor and Francis shall not be liable for any losses, actions, claims,
proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or
howsoever caused arising directly or indirectly in connection with, in relation to or arising
out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any
substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,
systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &

Conditions of access and use can be found at http://www.tandfonline.com/page/terms-
and-conditions

Synthetic Communications1, 42: 3579–3588, 2012
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397911.2011.585732
SYNTHESIS AND STRUCTURAL ANALYSIS OF SOME
PODANDS WITH C3 SYMMETRY
Adrian Woiczechowski-Pop, Ioana L. Dobra,
Gheorghe D. Roiban, Anamaria Terec, and Ion Grosu
Organic Chemistry Department, Faculty of Chemistry and Chemical
Engineering, Babes¸ Bolyai University, Cluj-Napoca, Romania
GRAPHICAL ABSTRACT
Abstract The multistep syntheses of C3-symmetrical tripodands with terminal triple bonds
or azide groups exhibiting 1,3,5-triarylbenzene and 2,4,6-triaryl-1,3,5-triazine cores are
reported herein. The structures of the newly synthesized compounds are supported by
NMR investigations.
Keywords Click reactions; cryptands; triarylbenzene; triaryltriazine; tripodands
INTRODUCTION
Three-dimensionally bridged cage molecules have proven a high capacity to act
as molecular hosts and represent a challenging target for investigations in supramol-
ecular chemistry.[1] The structurally well-defined cryptands cavities ensure highly
specific interactions with anionic, cationic, or neutral guests and support the forma-
tion of regio- and stereoselective supramolecular host–guest entities.[2] In addition,
the exciting properties of these supramolecular devices having various sized cavities
can be exploited in applications such as storage, delivery, molecular recognition, and
catalysis.[3] Therefore, the preparation of these molecules and of their intermediates
is of high importance. In particular, we were interested in developing synthetic pro-
cedures for tripodands with C3 symmetry and either triple bonds or azide groups
at the ends of their chains, which are suitable for ring closure using the click reac-
tion strategy.[4] In recent years interest has increased in the copper(I)-catalyzed
azido-alkyne cycloaddition (click reaction), and many applications of this reaction
Received April 17, 2011.
Address correspondence to Ion Grosu, Organic Chemistry Department, Faculty of Chemistry and
Chemical Engineering, Babes¸ Bolyai University, Arany Janos 11, 400028, Cluj-Napoca, Romania. E-mail:
igrosu@chem.ubbcluj.ro
3579

3580
A. WOICZECHOWSKI-POP ET AL.
Chart 1.
for the obtaining of host macrocycles were reported.[5] Despite the high interest for
the applications of the click reaction, the first synthesis of a cryptand using this reac-
tion was reported in 2008[6] and was followed by only a few other publications on
this subject.[7] The synthesis of new intermediates would therefore broaden the range
of available substrates and open the way for new interesting macrocyles. We con-
sidered developing synthetic methodologies to obtain the access to new podands (I
and II, Chart 1) exhibiting central benzene or triazine units and bearing terminal
alkyne or azide groups in the arms.
RESULTS AND DISCUSSION
The synthesis of podands bearing terminal triple bonds with tris(phenyl)-
benzene and tris(phenyl)triazine cores was carried out in several steps starting from
m-bromoacetophenone and p-hydroxybenzonitrile. The general synthetic strategy
for the preparation of podands with central phenyl units is depicted in Scheme 1
and follows two pathways.
Both synthetic methodologies required compound 2, which was obtained in
good yield by a trimerization reaction of m-bromoacetophenone in acidic conditions,
according to literature data for similar intermediates.[8]
The first pathway is the synthesis of compound 5 in a multistep reaction meth-
odology. Tris(biphenyl)benzene 3, obtained from tribromosubstituted derivative 2
by a Suzuki coupling reaction,[9] was used in a demethylation transformation with
pyridine hydrochloride at 200 ꢀC to afford derivative 4 in 76% yields.[10]
The NMR spectroscopy confirmed the C3 symmetry of compound 4. The aro-
matic region of 1H NMR spectrum of 4 exhibits the expected number and pattern of
resonances, with the singlet recorded for the central 1,3,5-trisubstituted benzene ring
and the AB system attributed to protons on the p-substituted phenyl rings being con-
sidered as key elements. The formation of the triphenolic form 4 was proven by the
presence in NMR spectrum of the new singlet attributed to the three hydroxyl
groups. Mass spectrometry (MALDI-TOF ESþ) revealed the molecular peak at
m=z 583.230.
The final step toward obtaining tripodand 5 was the phase-transfer reaction[11]
of triphenol 4 with propargyl bromide at room temperature in dichloromethane,
using 50% aqueous solution of NaOH and tributylammonium bromide. The propar-
gyl group was inserted on all three sites in fair yields (17%). The symmetrical struc-
1
ture of 5 was confirmed by NMR spectra. The H NMR spectrum exhibits in the
aromatic region the characteristic singlet for the central trisubstituted benzene core,

PODANDS WITH C3 SYMMETRY
3581
Scheme 1. Reagents and conditions: (i) F3CSO3H, toluene, reflux, 30 h; (ii) H3COPhB(OH)2, Pd(PPh3)4,
aqueous Na2CO3, THF–toluene 1:1, 90 ꢀC, Ar; (iii) HCl, pyridine, reflux, water, rt; (iv) 50% NaOH,
TBAB, propargyl bromide, rt; (v) n BuLi 1.6 M, dry THF, ꢁ78 ꢀC, dry DMF; (vi) NaBH4, H2O, THF,
rt; and (vii) 50% NaOH, TBAB, propargyl bromide, rt.

3582
A. WOICZECHOWSKI-POP ET AL.
and in the aliphatic region two signals are revealed, a doublet assigned for OCH2
protons and a triplet corresponding to CH protons from the propargyl groups.
In the second strategy, alcohols are used as precursors in the synthesis of
alkyne ligands. To this goal the synthesis of trisaldehyde 6 was performed, with
the chosen synthetic methodology representing an improved (90% yield) and less
toxic route (n-BuLi and dimethylformamide) than those found in literature[12] for
the synthesis of trisubstituted compounds with formyl group. Reduction of aldehyde
6 in (tetrahydrofurane) with solution of NaBH4 in H2O[13] led to the formation of
trisalcohol 7 in quantitative yields (98%). The advantages of this synthetic route
are the short reaction time and simple purification method. Compound 7 was sub-
jected to a similar reaction presented for the synthesis of 5. The greater yield of 8
(40%) compared to 5 can be explained by the greater reactivity of the anion of hydro-
xymethyl groups compared to the anions of phenol ones.
Symmetrical (C3) 1,3,5-triazine derivatives are playing an important role in
chemically selective processes and in supramolecular chemistry. They exhibit a high
ability to form hydrogen bonds, favor p–p contacts, and can be involved in different
anion–p interactions. Therefore the synthesis of some 1,3,5-tris(phenyl)-2,4,6-
triazine derivatives is of interest.[14,15b]
One of the target compounds, tripodand 11 (Scheme 2) was prepared in a
two-step reaction. First triphenol 10[15] was synthesized by a trimerization reaction
from commercially available p-hydroxybenzonitrile 9 and then the phenol was trans-
formed in trialkyne 11. Initially, a phase-transfer reaction was performed at room
temperature, using propargyl bromide in dichloromethane, 50% aqueous solution
of NaOH, and tributylammonium bromide. This reaction proved to be inefficient,
considering the poor yield obtained after workup (8%). The yield of the reaction
was substantially improved (42%) by an alternative reaction (K2CO3 in acetone at
reflux).[16]
1H NMR spectrum of 11 is in concordance with the proposed symmetric struc-
ture, the two types of protons of the p-disubstituted phenyl ring being assigned as an
AB system. The protons corresponding to propargyl groups are exhibited in ali-
phatic region of the spectrum as a doublet signal for methylene group and a more
shielded triplet signal for protons of the terminal triple bonds.
The synthesis of 13 was achieved by a trimerization reaction of compound 12
under argon, at room temperature using triflic acid in excess as solvent (90%) by a
similar procedure to that used in the case of triazine derivative 10. The triazide 14
Scheme 2. Reagents and conditions: (i) F3CSO3H, dry CHCl3, 0 ꢀC (2 h), rt (12 h); and (ii) propargyl
bromide, K2CO3, acetone, reflux.

PODANDS WITH C3 SYMMETRY
3583
Scheme 3. Reagents and conditions: (i) F3CSO3H, 0 ꢀC, rt (24 h) and (ii) NaN3, DMSO, rt.
was obtained in good yields (81%) by the reaction of 13 with NaN3 in dimethylsulf-
oxide, following a typical procedure (Scheme 3).[17]
1
The H NMR spectrum shows in the aromatic region an AB system for pro-
tons of the p-disubstituted ring and a singlet signal in aliphatic region corresponding
to protons of the methylene groups.
CONCLUSIONS
In summary, we have synthesized and structurally characterized several
podands with C3 symmetry by combining different synthetic methodologies. The
advantage of these building blocks is conferred by the extended aromatic units, which
assure rigidity to the cage molecules and are suitable for the formation of p-stacking
interactions with other aromatic derivatives. The structure of the compounds was
determined using NMR spectroscopy, mass spectrometry, and elemental analysis.
EXPERIMENTAL
Solvents were dried and distilled under argon using standard procedures before
use. Chemicals of commercial grade were used without further purification.
1H NMR, 13C NMR, correlation spectroscopy (COSY) and heteronuclear
multiple quantum correlation (HMQC) spectra were recorded at room temperature
using CDCl3 and dimethylsulfoxide (DMSO-d6) as solvents in 5-mm tubes on
Brucker 250 (operating at 250 MHz for protons and 60 MHz for carbon atoms), Bru-
ker Avance 300 (operating at 300 MHz for protons and 75 MHz for carbon atoms),
and Brucker AM 400 (operating at 400 MHz for protons and 100 MHz for carbon
atoms) instruments. Electrospray ionization instruments. (ESIþ) mass spectra were
recorded using an Esquire 3000 ion-trap mass spectrometer (Bruker Daltonic
GmbH) equipped with a standard ESI=APCI source, and an Agilent 6320 ionic trap
mass spectrometer equipped with a ESI=APCI source: The mass spectra (MALDIþ)
were recorded from CHCl3 solutions on a MALDI-TOF Microflex (Bruker)
spectrometer [2-[(2E)-3(4-tert-butylphenyl)-2-methylprop-2-enylidene]malononitrile
(DCTB) as matrix]. Thin-layer chromatography (TLC) was carried out on aluminum
sheets coated with silica gel 60 F254 using ultraviolet (UV) visualization. Preparative
column chromatography was performed using PharmPrep 60 CC (40–63 mm) silica
gel purchased from Merck. Elemental analyses were carried out on a Perkin-Elmer
2400-B microanalyzer.

3584
A. WOICZECHOWSKI-POP ET AL.
Synthesis of 4
Concentrated hydrochloric acid (55 mL) was added with vigorous stirring to
pyridine (60 mL), cooled to 0 ꢀC. After the addition was complete, the mixture
was heated and water distilled off until the internal temperature reached 200 ꢀC
(around 30 mL). The resulting pyridinium chloride was cooled to 140 ꢀC, and 3
(0.60 g, 0.96 mmol) was added in one portion. An immediate color change to red
occurred and heating to reflux was resumed for 4 h. The mixture was then allowed
to cool to 100 ꢀC, when water (100 mL) was added, and the mixture stirred for
12 h at room temperature. The brown precipitate that resulted was collected by fil-
tration, washed with plenty of water and chloroform, and dried under vacuum to
1
give 4 as a brown solid (0.43 g, 77%). H NMR (300 MHz, DMSO-d6) d ppm:
3
0
0
9.57 (s, 3H, OH), 8.03 (s, 3H, H2), 8.00 (s, 3H, H2 ), 7.79 (d, 3H, H6 , J ¼ 7.5 Hz),
3
00
0
00
0
7.65–7.61 (overlapped signals, 9H, H2 , H4 , H6 ), 7.54 (t, 3H, H5 , J ¼ 7.5 Hz), 6.86
(d, 6H, H3 , H5 , 3J ¼ 7.8 Hz). 13C NMR (75 MHz, DMSO-d6) d ppm: 157.25,
141.95, 140.95, 130.92, 129.41, 128.16, 125.56, 125.02, 115.70. MS (MALDI-TOF
ESþ) [M þ H]þ m=z 583.230. Anal. calcd. for C42H30O3 (582.69): C, 86.57; H,
5.19. Found: C, 86.76; H, 5.34.
00
00
Synthesis of 5
A 50% aqueous solution of NaOH (0.248 g, 36 equiv., 6.18 mmol) was added to
a solution of 4 (0.100 g, 1 equiv., 0.172 mmol) in 6 mL dichloromethane. After cool-
ing to 0 ꢀC, TBAB (0.042 g, 0.75 equiv., 0.128 mmol) was added. The mixture was
stirred for half an hour at this temperature, and then propargyl bromide 80% in tolu-
ene (0.092 g, 3.6 equiv., 0.618 mmol) was added. The mixture was allowed to stir
overnight at room temperature. The resulted suspension was extracted with dichlor-
omethane (DCM). Combined organic phases were washed with water and brine,
dried over Na2SO4, and filtered, and the solvent was removed under reduced press-
ure. The crude product was purified by column chromatography on silica gel (eluent
1
AcOEt–pentane 1:3) to obtain compound 5 (0.020 g, 17%). H NMR (400 MHz,
0
CDCl3) d ppm: 7.89 (s, 3H, H2), 7.87 (s, 3H, H2 ), 7.67–7.52 (overlapped signals,
3
4
00
15H, Harom), 7.08 (d, 6H, J ¼ 8.4 Hz, H3 ), 4.75 (d, 6H, J ¼ 2.4 Hz, OCH2), 2.55
(t, 3H, J ¼ 2.4 Hz, C ꢂ CH). 13C NMR (100 MHz, CDCl3) d ppm: 157.21, 142.48,
4
141.62, 141.36, 134.50, 129.90, 128.33, 126.10, 125.97, 125.91, 125.45, 115.24,
78.48, 75.64, 55.88. Anal. calcd. for C51H36O3 (696.83): C, 87.90; H, 5.21. Found:
C, 88.08; H, 5.32.
Synthesis of 6
1,3,5-Tris-(3-bromophenyl)benzene (2) (1.80 g, 1 equiv., 3.31 mmol) was dis-
solved in anhydrous tetrahydrofuran (THF) in a two-necked round bottom flask
under argon atmosphere. After cooling to ꢁ78 ꢀC, nBuLi 1.6 M (10.36 mL, 5 equiv.,
16.57 mmol) was added dropwise with a syringe. The lithiated intermediate was kept
approximately 30 min at ꢁ78 ꢀC and anhydrous DMF (2.58 mL, 10 equiv.,
33.14 mmol) was added dropwise to the solution. The mixture was left to reach room
temperature and then HCl 0.1 M and H2O were added until the solution clarified.

PODANDS WITH C3 SYMMETRY
3585
The solution was concentrated until the THF was removed. The precipitate was
filtered and recrystallized from acetone to afford 6 as a white solid (1.16 g, 90%).
1H NMR (300 MHz, CDCl3) d ppm: 10.14 (s, 3H, CHO), 8.23 (pseudotriplet, 3H,
4
4
3
4
4
0
0
H2 , J ¼ J’ ¼ 1.5 Hz), 7.99 (overlapped dd, 3H, H4 , J ¼ 7.5 Hz, J ¼ J’ ¼ 1.8 Hz),
3
4
4
0
7.94 (overlapped dd, 3H, H6 , J ¼ 7.5 Hz, J ¼ J’ ¼ 1.2 Hz), 7.89 (s, 3H, H2), 7.70
(t, 3H, H5 , 3J ¼ 7.5 Hz). 13C NMR (75 MHz, CDCl3) d ppm: 192.29, 141.59,
0
137.14, 133.38, 129.86, 129.59, 128.19, 125.83. Anal. calcd. for C27H18O3 (390.43):
C, 83.06; H, 4.65. Found: C, 82.88; H, 4.80.
Synthesis of 7
A solution of sodium borohydride (0.39 g, 15 equiv., 10.37 mmol) in 2.50 mL
water was added dropwise to 6 (0.27 g, 1 equiv., 0.69 mmol) dissolved in 10 mL
THF. The mixture was allowed to stir at room temperature for 1 h and then washed
with ethyl acetate. The organic layer was dried over Na2SO4 and evaporated under
1
vacuum to afford compound 7 as white powder (0.27 g, 98%). H NMR (300 MHz,
3
0
0
DMSO-d6) d ppm: 7.87 (s, 3H, H2), 7.78 (s, 3H, H2 ), 7.73 (d, 3H, H4 , J ¼ 7.2 Hz),
7.48 (t, 3H, H5 , J ¼ 7.5 Hz), 7.38 (d, 3H, H6 , 3J ¼ 7.5 Hz), 5.28 (t, 3H, OH,
3J ¼ 5.7 Hz), 4.61 (d, 6H, CH2, 3J ¼ 5.7 Hz). 13C NMR (75 MHz, DMSO-d6) d
ppm: 143.18, 141.64, 139.74, 128.62, 125.75, 125.36, 125.02, 124.13, 62.76. MS
(APCIþ) m=z ¼ 418.895 [M þ Na]þ, m=z ¼ 815.814 [2M þ Na]þ. Anal. calcd. for
C27H24O3 (396.48): C, 81.79; H, 6.10. Found: C, 81.63; H, 5.89.
3
0
0
Synthesis of 8
A 50% aqueous solution of NaOH (0.671 g, 36 equiv., 16.8 mmol) was added to
a solution of 7 (0.185 g, 1 equiv., 0.466 mmol) in 6 mL CH2Cl2. After cooling to 0 ꢀC,
TBAB (0.113 g, 0.75 equiv., 0.350 mmol) was added. The mixture was stirred for half
an hour at this temperature and then propargyl bromide 80% in toluene (0.25 g, 3.6
equiv., 1.68 mmol) was added. The mixture was allowed to stir overnight at room
temperature. The resulting suspension was extracted with CH2Cl2. Combined
organic phases were washed with water and brine, dried over Na2SO4, and filtered,
and the solvent was removed under reduced pressure. The crude product was puri-
fied by column chromatography on silica gel (eluent AcOEt–pentane 1:3) to obtain
1
the pure compound 8 (0.094 g, 40%). H NMR (250 MHz, CDCl3) d ppm: 7.79 (s,
3
0
0
0
3H, H2), 7.70 (s, 3H, H2 ), 7.64 (d, 3H, H4 , J ¼ 7.5 Hz), 7.48 (t, 3H, H5 ,
J ¼ 7.5 Hz), 7.39 (d, 3H, H6 , 3J ¼ 7.5 Hz), 4.71 (s, 6H, CH2O), 4.25 (d, 6H,
3
0
OCH2, J ¼ 2.5 Hz), 2.50 (t, 3H, CH, J ¼ 2.5 Hz). 13C NMR (100 MHz, CDCl3) d
ppm: 142.09, 141.26, 137.91, 128.97, 127.29, 127.05, 126.94, 125.27, 79.57, 74.79,
71.50, 57.23. Anal. calcd. for C36H30O3 (510.62): C, 84.68; H, 5.92. Found: C, 84.84;
H, 5.68.
3
3
Synthesis of 11
Compound 10 (0.100 g, 1 equiv., 0.28 mmol) and propargyl bromide 80% in
toluene (0.15 g, 3.6 equiv., 1.01 mmol) were allowed to reflux overnight in acetone
in the presence of K2CO3(0.58 g, 15 equiv., 4.20 mmol). The mixture was partitioned

3586
A. WOICZECHOWSKI-POP ET AL.
between water and ethyl acetate. Combined organic fractions were dried over
MgSO4, and the solvent was removed. Purification by column chromatography (elu-
1
ent AcOEt–pentane 1:5) furnished compound 11 as a white solid (0.055 g, 42%). H
3
0
0
0
NMR (250 MHz, CDCl3) d ppm: 8.72 (d, 6H, H2 , H6 , J ¼ 7.5 Hz), 7.14 (d, 6H, H3 ,
3
3
3
0
H5 , J ¼ 7.5 Hz), 4.82 (d, 6H, OCH2, J ¼ 2.5 Hz), 2.58 (t, 3H, CꢂCH, J ¼ 2.5 Hz).
13C NMR (125 MHz, CDCl3) d ppm: 170.79, 161.11, 130.82, 129.98, 114.87, 78.24,
76.10, 56.01. MS (ESIþ) m=z ¼ 472.2 [M þ H]þ. Anal. calcd. for C30H21N3O3
(471.51): C, 76.42; H, 4.49; N, 8.91. Found: C, 76.68; H, 4.71; N, 8.82.
Synthesis of 14
NaN3 (0,080 g, 3.6 equiv., 1.22 mmol) was added to a stirred solution of com-
pound 13 (0.2 g, 1 equiv., 0.34 mmol) in DMSO (10 mL). The solution was allowed to
stir at room temperature overnight. The mixture was washed with ethyl acetate
(3 ꢃ 25 mL). The reunited organic phases were dried over Na2SO4, and the solvent
was evaporated in vacuo. The purification by column chromatography on silica
gel (eluent CH2Cl2–pentane 1:2) gave the pure compound 14 as a straw-colored
1
oil, which solidifies in the refrigerator (0.130 g, 81%). H NMR (250 MHz, CDCl3)
3
3
0
0
0
0
d ppm: 8.54 (d, 6H, H2 , H6 , J ¼ 7.5 Hz), 7.36 (d, 6H, H3 , H5 , J ¼ 7.5 Hz), 4.34
(s, 6H, CH2N3). 13C NMR (125 MHz, CDCl3) d ppm: 140.63, 132.25, 128.25,
118.22, 111.62, 53.60. Anal. calcd. for C24H18N12 (474.48): C, 60.75; H, 3.82; N,
35.42. Found: C, 60.49; H, 3.89; N, 35.21.
REFERENCES
1. (a) Gleiter, R.; Hopf, H. Modern Cyclophane Chemistry; Wiley: Weinheim; VCH Verlag
GmbH & Co. KGaA Ed.; 2004; (b) Steed, J. W.; Atwood, J. L. Supramolecular Chemistry,
Second Edition; Wiley: Wiltshire; John Wiley & Sons Ed.; 2009; (c) Diedrich, F.; Stang,
P. J.; Tykwinski, R. R. Modern Supramolecular Chemistry: Strategies for Macrocycle
Synthesis, Wiley: Weinheim; VCH Verlag GmbH & Co. KGaA Ed; 2008; (d) Lehn,
J. -M. Supramolecular Chemistry: Concepts and Perspectives, Wiley: Weinheim; VCH
Verlagsgesellschaft mbH Ed.; 1995.
2. (a) Tos¸a, N.; Bende, A.; Varga, R. A.; Terec, A.; Bratu, I.; Grosu, I. H-Bond-Driven
Supramolecular Architectures of the Syn and Anti Isomers of the Dioxime of
Bicyclo[3.3.1]nonane-3,7-dione. J. Org. Chem. 2009, 74, 3944–3947; (b) Wang, F.; Zhou,
Q.; Zhu, K.; Li, S.; Wang, C.; Liu, M.; Li, N.; Fronczek, F. R.; Huang, F. Efficient synth-
eses of bis(m-phenylene)-26-crown-8-based cryptand=paraquat derivative [2]rotaxanes by
immediate solvent evaporation method. Tetrahedron 2009, 65, 1488–1494; (c) Bond, A. D.;
Fleming, A.; Gaire, J.; Kelleher, F.; McGinley, J.; McKee, V. First X-ray structural
characterisation of host–guest interactions in tetra-tetrazole macrocycles. Tetrahedron
2009, 65, 7942–7947; (d) Muller, T. Splendid Isolation for a Nonmetallic Dication. Angew.
¨
Chem. Int. Ed. 2009, 48, 3740–3743; (e) Menand, M.; Leroy, A.; Marrot, J.; Luhmer, M.;
´
Jabin, I. Induced-Fit Encapsulation by a 1,3,5-Alternate Calix[6]arene. Angew. Chem. Int.
Ed. 2009, 48, 5509–5512; (f) Park, J. S.; Karnas, E.; Ohkubo, K.; Chen, P.; Kadish, K. M.;
Fukuzumi, S.; Bielawski, C. W.; Hudnall, T. W.; Lynch, V. M.; Sessler, J. L. Ion-
Mediated Electron Transfer in a Supramolecular Donor-Acceptor Ensemble. Science
2010, 329, 1324–1327; (g) He, Q. -T.; Li, X. -P.; Liu, Y.; Yu, Z. -Q.; Wang, W.; Su, C.
-Y. Copper(I) Cuboctahedral Coordination Cages: Host-Guest Dependent Redox

PODANDS WITH C3 SYMMETRY
3587
Activity. Angew. Chem. Int. Ed. 2009, 48, 6156–6159; (h) Brotin, T.; Dutasta, J. -P. Cryp-
tophanes and Their Complexes-Present and Future. Chem. Rev. 2009, 109, 88–130; (i)
Das, M. C.; Ghosh, S. K.; Bharadwaj, P. K. Diversity of binding of sulfate and nitrate
anions with laterally asymmetric aza cryptands. Cryst. Eng. Comm. 2010, 12, 413–419;
(j) Saeed, M. A.; Fronczek, F. R.; Hossain, M. A. Encapsulated chloride coordinating
with two in-in protons of bridgehead amines in an octaprotonated azacryptand. Chem.
Commun. 2009, 6409–6411; (k) Foster, J. A.; Steed, J. W. Exploiting Cavities in Supramol-
ecular Gels. Angew. Chem. Int. Ed. 2010, 49, 6718–6724.
3. (a) Chang, K. -J.; Moon, D.; Lah, M. S.; Jeong, K. -S. Indole-Based Macrocycles as a
Class of Receptors for Anions. Angew. Chem. Int. Ed. 2005, 44, 7926–7929; (b) Rebek,
J. Jr. Simultaneous Encapsulation: Molecules Held at Close Range. Angew. Chem. Int.
Ed. 2005, 44, 2068–2078; (c) Jin, Y.; Voss, B. A.; Noble, R. D.; Zhang, W. A Shape-
Persistent Organic Molecular Cage with High Selectivity for the Adsorption of CO2 over
N2. Angew. Chem. Int. Ed. 2010, 49, 6348–6351; (d) Badjic
Silvi, S.; Stoddart, J. F. A Molecular Elevator. Science 2004, 303, 1845–1849; (e) Badjic
´
´
, J. D.; Balzani, V.; Credi, A.;
,
J. D.; Nelson, A.; Cantrill, S. J.; Turnbull, W. B.; Stoddart, J. F. Multivalency and
Cooperativity in Supramolecular Chemistry. Acc. Chem. Res. 2005, 38, 723–732; (f)
Sessler, J. L.; Davis, J. M. Sapphyrins: Versatile Anion Binding Agents. Acc. Chem.
Res. 2001, 34, 989–997.
4. (a) Lahann, J. Click Chemistry for Biotechnology and Materials Science; Wiley: John Wiley
& Sons Ltd. Ed.; 2009; (b) Hein, C. D.; Liu, X. -M.; Wang, D. Click Chemistry, A Power-
ful Tool for Pharmaceutical Sciences. Pharm. Res. 2008, 25, 2216–2230; (c) Kolb, H. C.;
Finn, M. G.; Sharpless, K. B. Click Chemistry: Diverse Chemical Function from a Few
Good Reactions. Angew. Chem. Int. Ed. 2001, 40, 2004–2021; (d) Moses, J. E.;
Moorhouse, A. D. The growing applications of click chemistry. Chem. Soc. Rev. 2007,
36, 1249–1262; (e) Iha, R. K.; Wooley, K. L.; Nystro¨m, A. M.; Burke, D. J.; Kade, M.
J.; Hawker, C. J. Applications of Orthogonal ‘‘Click’’ Chemistries in the Synthesis of
Functional Soft Materials. Chem. Rev. 2009, 109, 5620–5686; (f) Amblard, F.; Cho, J.
H.; Schinazi, R. F. Cu(I)-Catalyzed Huisgen AzideꢁAlkyne 1,3-Dipolar Cycloaddition
Reaction in Nucleoside, Nucleotide, and Oligonucleotide Chemistry. Chem. Rev. 2009,
109, 4207–4220.
5. (a) Moni, L.; Rossetti, S.; Scoponi, M.; Marra, A.; Dondoni, A. Immobilization of
calix[4]arene-based glycoclusters on TiO2 nanoparticles via click Cu(I)-catalyzed azide-
alkyne coupling. Chem. Commun. 2010, 46, 475–477; (b) Morales-Sanfrutos, J.;
˜
Ortega-Munoz, M.; Lopez-Jaramillo, J.; Hernandez-Mateo, F.; Santoyo-Gonzalez, F.
Synthesis of Calixarene-Based Cavitands and Nanotubes by Click Chemistry. J. Org.
Chem. 2008, 73, 7768–7771; (c) Chang, K. -C.; Su, I. -H.; Wang, Y. -Y.; Chung, W. -S.
A Bifunctional Chromogenic Calix[4]arene Chemosensor for Both Cations and Anions:
A Potential Ca2þ and F– Switched INHIBIT Logic Gate with a YES Logic Function.
Eur. J. Org. Chem. 2010, 24, 4700–4704.
6. Morales-Sanfrutos, J.; Ortega-Mun˜oz, M.; Lopez-Jaramillo, J.; Hernandez-Mateo, F.;
Santoyo-Gonzalez, F. Synthesis of Molecular Nanocages by Click Chemistry. J. Org.
Chem. 2008, 73, 7772–7774.
7. (a) Steinmetz, V.; Couty, F.; David, O. R. P. One-step synthesis of chiral cages. Chem.
Commun. 2009, 343–345; (b) Couty, F.; David, O. R. P. Synthesis of an ovoid chiral cage.
Synlett. 2009, 1945–1948.
8. (a) Weber, E.; Hecker, M.; Koepp, E.; Orlia, W.; Czugler, M.; Cso¨regh, I. New trigonal
lattice hosts: stoicheiometric crystal inclusions of laterally trisubstituted benzenes—X-ray
crystal structure of 1,3,5-tris-(4-carboxyphenyl)benzene ꢄ dimethylformamide. J. Chem.
Soc., Perkin Trans. 2 1988, 1251–1257; (b) Wallon, A.;Werner, U.; Muller, W. M.; Vo¨gtle,
¨
F.; Nieger, M. Pentamakrocyclische Tris-Kronen – Selektive Bindung von Kationen,

3588
A. WOICZECHOWSKI-POP ET AL.
Anionen und Neutralverbindungen. Chem. Ber. 1990, 123, 859–867; (c) Kim, Y. H.;
Beckerbauer, R. Role of End Groups on the Glass Transition of Hyperbranched Polyphe-
nylene and Triphenylbenzene Derivatives. Macromolecules 1994, 27, 1968–1971; (d)
Brunel, J.; Jutand, A.; Ledoux, I.; Zyss, J.; Blanchard-Desce, M. Boomerang-shaped octu-
polar molecules derived from triphenylbenzene. Synth. Met. 2001, 124, 195–199.
9. Kotha, S.; Kashinath, D.; Lahiri, K.; Sunoj, R. B. Synthesis of C3-Symmetric Nano-Sized
Polyaromatic Compounds by Trimerization and Suzuki-Miyaura Cross-Coupling Reac-
tions. Eur. J. Org. Chem. 2004, 4003–4013.
10. Constable, E. C.; Housecroft, C. E.; Neuburger, M.; Poleschak, I.; Zehnder, M. Functio-
nalised 2,20-bipyridine ligands for the preparation of metallostars; X-ray structures of free
ligands and preparation of copper(I) and silver(I) complexes. Polyhedron 2003, 22, 93–108.
11. Bogdan, N. D.; Matache, M.; Meier, V. M.; Dobrota, C.; Dumitru, I.; Roiban, G. D.;
Funeriu, D. P. Protein-Inorganic Array Construction: Design and Synthesis of the
Building Blocks. Chem. Eur. J. 2010, 16, 2170–2180.
12. (a) Brunel, J.; Mongin, O.; Jutand, A.; Ledoux, I.; Zyss, J., Blanchard-Desce, M.
Propeller-Shaped Octupolar Molecules Derived from Triphenylbenzene for Nonlinear
Optics: Synthesis and Optical Studies. Chem. Mater. 2003, 15, 4139–4148; (b) Brunel,
J.; Ledoux, I.; Zyss, J.; Blanchard-Desce, M. Propeller-shaped molecules with giant
off-resonance optical nonlinearities. Chem. Commun. 2001, 923–924; (c) Rajakumar, P.,
Swaroop, M. G., Jayavelu, S., Murugesan, K. Synthesis, complexation studies and bio-
logical applications of some novel stilbenophanes, indolophanes and bisindolostilbeno-
phanes via McMurry coupling. Tetrahedron 2006, 62, 12041–12050; (d) Mongin, O.,
Brunel, J., Porres, L., Blanchard-Desce, M. Synthesis and two-photon absorption of
triphenylbenzene-cored dendritic chromophores. Tetrahedron Lett. 2003, 44, 2813–2816;
(e) Porres, L., Mongin, O., Blanchard-Desce, M. Synthesis, fluorescence and two-photon
absorption properties of multichromophoric boron-dipyrromethene fluorophores for
two-photon-excited fluorescence applications. Tetrahedron Lett. 2006, 47, 1913–1917.
´
13. Badjic, J. D.; Cantrill, S. J.; Stoddart, J. F. Can Multivalency Be Expressed Kinetically?
The Answer Is Yes. J. Am. Chem. Soc. 2004, 126, 2288–2289.
´
´
´
14. Garcıa, A.; Insuasty, B.; Herranz, M. A.; Martınez-Alvarez, R.; Martın, N. New Building
Block for C3 Symmetry Molecules: Synthesis of s-Triazine-Based Redox Active Chromo-
phores. Org. Lett. 2009, 11, 5398–5401.
15. (a) Lee, C. -H.; Yamamoto, T. Synthesis and characterization of a new class of
liquid-crystalline, highly luminescent molecules containing a 2,4,6-triphenyl-1,3,5-triazine
unit. Tetrahedron Lett. 2001, 42, 3993–3996; (b) Ranganathan, A.; Heisen, B. C.; Dix, I.;
Meyer, F. A triazine-based three-directional rigid-rod tecton forms a novel 1D channel
structure. Chem. Commun. 2007, 3637–3639.
16. Kim, S. H.; Choi, H. S.; Kim, J.; Lee, S. J.; Quang, D. T.; Kim, J. S. Novel Optical=
Electrochemical Selective 1,2,3-Triazole Ring-Appended Chemosensor for the Al3þ Ion.
Org. Lett. 2010, 12, 560–563.
17. Sinha, J.; Sahoo, R.; Kumar, A. Processable, Regioregular, and ‘‘Click’’able Monomer
and Polymers Based on 3,4-Propylenedioxythiophene with Tunable Solubility. Macro-
molecules 2009, 42, 2015–2022.