Self-assembly of rectangles via building units bearing salen and oxazoline ligands

Article abstract of DOI:10.1016/j.jorganchem.2006.09.063

Rigid spacer-chelator with the framework of 3 has been prepared. Building units with two parallel coordination sites such as salen and oxazoline units have also been synthesized. The spacer-chelators, 11 and 15, readily self-assembled with metal complexes

Full text of DOI:10.1016/j.jorganchem.2006.09.063

Journal of Organometallic Chemistry 691 (2006) 5946–5954
www.elsevier.com/locate/jorganchem
Self-assembly of rectangles via building units bearing salen
and oxazoline ligands
*
*
Duckhyun Kim, Il Jung, Kyu Ho Song, Sang Ook Kang , Jaejung Ko
Department of Chemistry, Korea University, Jochiwon, Chungnam 339-700, Republic of Korea
Received 22 August 2006; received in revised form 26 September 2006; accepted 28 September 2006
Available online 12 October 2006
Abstract
Rigid spacer-chelator with the framework of 3 has been prepared. Building units with two parallel coordination sites such as salen and
oxazoline units have also been synthesized. The spacer-chelators, 11 and 15, readily self-assembled with metal complexes such as Zn++
and Co++ to form molecular rectangles. The overall dimensions of the rectangles, 13 and 17, are 6.2 A · 23.5 A. The characterization of
the supramolecules by NMR, mass spectroscopy, and X-ray crystal structures is also reported.
ꢀ 2006 Elsevier B.V. All rights reserved.
˚
˚
Keywords: Self-assembly; Rectangle; Salen; Oxazoline; Molecular clip; Rigid spacer-chelator
1. Introduction
by several flexible binucleating ligands [10], the rigid
building units such as 1, 2, and 3 provides a cavity of
well-defined size and shape.
The metal-directed self-assembly of supramolecular
entities from discrete molecular ensembles has received
considerable attention [1]. The interest in these macrocy-
cles arises from their size- and shape-selective properties
with potential applications in catalysis and sensing
devices [2]. The directed assembly of supramolecules
has proven to be very effective for construction of well-
defined supramolecular entities such as squares [1,3], tri-
angles [4], hexagons [5], and cubes [6]. As lower symme-
try hosts can be expected to show enhanced guest
selectivity [7], rectangles represent a crucial geometrical
model in the development of this area. Despite their rel-
ative simplicity, molecular rectangles are much less com-
mon [8]. The difficulty in the construction of rectangles
lies in the necessity of designing a building unit with
two parallel coordination sites facing in the same direc-
tion [9]. Although the molecular rectangles were formed
R
N
1
2
3
The spacer, 1, incorporating two acetylacetonate or
dithiocarbamate chelators was found by Maverick [11]
and Beer [12] groups to give the Cu++ cofacial complexes.
Stang and co-workers [13] have described the self-assem-
bly reactions of a molecular‘clip’, 4, as an efficient entry
into the rectangular shape with the antracene framework
(2). Bosnich and co-workers [14] have reported the molec-
ular recognition and self-assembly using rigid spacer-che-
*
Corresponding authors. Tel.: +82 41 860 1337; fax: +82 41 867 5396
(J. Ko and S.O. Kang).
E-mail address: jko@korea.ac.kr (J. Ko).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.09.063

D. Kim et al. / Journal of Organometallic Chemistry 691 (2006) 5946–5954
5947
lator, 5, bearing cofacial terpyridyl palladium(II)
complexes.
Herein, we describe the metal-directed self-assembly
reactions and characterization of the members of a family
of molecular rectangles via a new type of subunit.
N
PEt3
Pt ONO2
PEt3
2. Results and discussion
N
N
2.1. Synthesis of spacer-chelator (11)
R
N
PEt3
N
N
Our strategy for the synthesis of self-assembled supra-
molecules of molecular rectangles utilizes the building unit
with two parallel coordination sites facing in the same
direction. The synthesis of spacer-chelator, 11, followed
many of the procedures described previously for analogous
compounds [15,16]. The synthetic steps are outlined in
Scheme 1.
Pt ONO2
PEt3
N
4
5
Recently, we [15] have reported the self-assembly of rect-
angles via a molecular ‘‘clip’’, 6, as shown. Accordingly, we
envisioned that if we could incorporate coordinating
groups such as salen and oxazoline units into the rigid
framework, 3, such a subunit would offer another entry
into new rectangles for catalysis and guest substrate.
The synthesis of 11 is conveniently prepared in four
steps from the 2,12-dibromo-[7-(3,5-di-tert-butylphenyl)-
5,6,8,9-tetrahydrodibenzo[c, h]acridine] (7). The spacer, 7,
is efficiently oxidized to the all-aromatic compound, 8,
with DDQ in dioxane in 67% yield. The Sonogashira cou-
pling of 8 with 3 equiv. of trimethylsilylacetylene followed
by basic hydrolysis yielded 9 in 84% yield. The palladium
catalyzed cross-coupling of 3 equiv. of 3-tert-butyl-2-
hydroxy-5-iodobenzaldehyde [17] with 9 afforded 10 in
87% yield. The mass spectrum of 10 showed a molecular
ion at m/z 868. A low-field resonance due to the aldehyde
proton and alcohol were detected at 9.61 and 11.88 ppm in
PEt3
Pt ONO2
PEt3
N
PEt3
Pt ONO2
PEt3
1
the H NMR spectrum, respectively. The spacer-chelator,
11, was readily synthesized by the reaction of 10 with
(R,R)-diaminocyclohexane tartrate salt and potassium
carbonate.
6
Br
Br
H
H
Br
(b)
(a)
N
N
N
Br
8
9
7
H
O
OH
N
OH
(d)
(c)
N
N
H
N
H
O
O
OH
OH
OH
H3N
O2C
NH3
CO2
I
HO
OH
11
10
Scheme 1. aKey: (a) DDQ, 1,4-dioxane; (b) (i) trimethylsilylacetylene, Pd(PPh3)4, CuI, NEt3, (ii) MeOH, NaOH, THF; (c) Pd(PPh3)4, CuI, NEt3;
(d) K2CO3, H2O, THF.

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D. Kim et al. / Journal of Organometallic Chemistry 691 (2006) 5946–5954
2.2. Synthesis of complexes (12 and 13)
N
N
The synthetic methodology using the metal directional
approach for molecular self-assembly has been well docu-
mented [19]. We had already demonstrated the formation
of molecular rectangles using a molecular clip in combina-
tion with 4,40-bipyridyl and isocyanide donor ligands [15].
To diversify the synthetic approach to the previous strat-
egy, we have selected the ligand (11) as a rigid organic clip
in combination with the 3d-metal acetate as linear linker.
Recently, many research groups [20] have reported a family
of metal complexes having two phenoxy-imine chelate
ligands for olefin polymerization. However, coordination-
driven self-assembly of discrete molecular entities using
phenoxy-imine chelate ligand has never been explored.
Zn(II) and Co(II) acetates were successfully reacted with
ligand 11 in an 1:1 ratio, resulting in the formation of dime-
tallic rectangular products as shown.
HO
OH
N
N
HO
N
OH
N
A
Initially we expected the bis(salen) ligand, A, as a prod-
uct with two parallel sites facing in the same direction
through the reaction of 11 and (R,R)-aminocyclohexane.
The initial indication of an unexpected formulation for
11 stemmed from the observation of a parent ion in the
1
mass spectrum at m/z 946. H NMR signals ascribable to
O
N
N
O
O
N
N
O
the alcohol and imine protons were observed at 14.17
and 8.41 ppm, respectively. The alcohol signal in 11 had
clearly shifted from 11.88 ppm in 10 to 14.17 ppm due to
the hydrogen bonding between the imine and alcohol.
The value is comparable to that observed for the salen che-
lator ligand [18]. Judged from above spectroscopic data
and elemental analysis, the structure of 11 can be reason-
ably assigned.
M
M
N
N
M = Co ( 12 ), Zn ( 13 )
Fig. 1. (a) ORTEP drawing [28] of rectangle 12 with thermal ellipsoids drawn at the 30% probability level. Hydrogen atoms and solvent molecules are
omitted for clarity. (b) Packing diagram of 12 in the molecular layer.

D. Kim et al. / Journal of Organometallic Chemistry 691 (2006) 5946–5954
5949
To provide structural information for one of the new
compounds prepared, a single-crystal X-ray diffraction
study of the cobalt product 12 was undertaken. The molec-
ular structure and packing diagram of 12 are shown in
Fig. 1. A summary of cell constants and data collection
parameters is appeared in the reference [21].
proton. The two resonances can be attributed to the envi-
ronmental difference of two imines.
2.3. Synthesis of spacer-chelator (15)
The synthesis of 15 is given in Scheme 2. The 2-(4,4-dim-
ethyloxazolin-2-yl)-4-iodophenol (14) was obtained by the
condensation reaction of 5-iodosalicylic acid with 2-
amino-2-methyl-1-propanol in 90% yield. 2,12-Bis[3-(4,
4-dimethyloxazolin-2-yl)-4-hydroxyphenylethynyl]-[7-(3,5-
di-tert-butyl)phenyl]dibenzo[c,h]acridine (15) was synthe-
sized by the cross-coupling of 14 and 9. All of the new
compounds were fully characterized with spectroscopic
The X-ray crystal structure of 12 confirmed the presence
of a discrete neutral rectangular molecule. The structure
consists of a dicobalt motif and two organic connectors
per formula unit. Two cobalt atoms, Co(1) and Co(2), have
the usual four-coordinate tetrahedral cobalt coordination.
The Co(1) atom is coordinated by two phenoxy-imine che-
lated atoms. The dinuclear cobalt compound in 12 may be
attributed to the strong tendency to form a stable four-
coordinate configuration. The environment of two cobalts,
Co(1) and Co(2), is slightly different due to the presence of
diaminocyclohexyl group exhibiting the chiral characteris-
1
techniques, including H and 13C NMR spectroscopy and
high-resolution mass spectroscopy. The 13C NMR spec-
trum of 15 reveals the expected 21 lines in the aromatic
region. 1H NMR signal assigned as the alcohol was
observed at 12.53 ppm. The mass spectrum of 15 showed
a molecular ion at m/z 894.
˚
tics. Therefore, the bond distances of O1–O1_3 (3.111 A),
˚
˚
N1–N1_3 (3.581 A) in Co(1) and O2–O2_3 (3.349 A),
˚
N2–N2_3 (3.149 A) in Co(2) are different. The packing dia-
gram of 12 exhibits a characteristic p–pstacking between
two dibenzoacridine units of different molecules. The inter-
molecular distance is 3.45 A. The rectangular molecule is
2.4. Synthesis of complexes (16 and 17)
˚
found to be bented upward about 7ꢁ due to the face–face
intermolecular interaction. Spectroscopic data for 13 are
consistent with its proposed structure. The MALDI-mass
spectrum of 13 showed a molecular ion at m/z 2018
As a variety of metal complexes containing oxazoline
ligand have been well-established [22], we attempted the
self-assembly of rectangles using a molecular clip 15. The
molecular rectangles of 16 and 17 were obtained by the reac-
tion of metal acetates with ligand 15 in a mixture of ethanol
and toluene as shown below.
1
[MH]+(see Fig. 2). The H NMR spectrum of 13 exhibits
two singlets at 8.46 and 8.44 ppm assigned to the imine
Fig. 2. MALDI-mass spectrum of compound 13.

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D. Kim et al. / Journal of Organometallic Chemistry 691 (2006) 5946–5954
O
O
N
OH
O
COOH
OH
(a)
(b)
N
N
N
I
NH2
I
OH
OH
OH
14
15
Scheme 2. aKey: (a) PPh3, NEt3, CH2Cl2, CHCl3; (b) 9, Pd(PPh3)4, CuI, NEt3.
The complexes of 16 and 17 are highly soluble in com-
mon organic solvents such as dichloromethane and chloro-
form. Both complexes are stable enough to handle in air
and can be stored for a long time. Complexes 16 was struc-
O
O
N
N
M
M
O
N
O
O
1
turally characterized by H and 13C NMR spectroscopy
O
N
O
N
N
O
1
and mass spectroscopy. H NMR of complex 16 showed
the disappearance of the phenoxo-OH proton. However,
other protons exhibited only slight changes in the chemical
shifts compared with those of the corresponding unbound
M = Zn ( 16 ), Co ( 17 )
Fig. 3. (a) ORTEP drawing of rectangle 17 with thermal ellipsoids drawn at the 30% probability level. Hydrogen atoms and solvent molecules are omitted
for clarity. (b) Packing diagram of 17 in the molecular layer.

D. Kim et al. / Journal of Organometallic Chemistry 691 (2006) 5946–5954
5951
ligand 15. The 13C NMR of 16 reveals the expected 21 lines
in the aromatic region. The mC@N vibration for 16 is found
at 1602 cmꢀ1, and is shifted by 20–25 cmꢀ1 to a lower fre-
quency compared to the free ligand 15, indicating that the
imine nitrogen of the oxazoline ring is strongly coordinated
to the metal center. The mass spectrum of 16 showed a
molecular ion at m/z 1916.
The structure of 17 was established by single-crystal X-
ray analysis and is shown in Fig. 3. The crystallographic
data and processing parameters are given in the reference
[23]. The geometry around the cobalt center is common tet-
rahedral configuration with two units of bidentate (N, O)
oxazoline ligands. The bond lengths and angles of primary
coordination sphere are comparable to the other reported
cobalt complexes [24]. The average Co(1)–O bond length
analyzer. 5-Iodosalicylic acid, 2-amino-2-methyl-1-propa-
nol were purchased from Aldrich Chemical Co. 2,12-Dib-
romo-[7-(3,5-di-tert-butylphenyl)-5,6,8,9-tetrahydro-dib-
enzo[c, h]acridine] were prepared according to the
literature methods [15].
4.2. Synthesis of 2,12-dibromo-[7-(3,5-di-tert-
butylphenyl)dibenzo[c,h]acridine] (8)
A 100 ml flask equipped with a condenser was flame
dried under a continuous stream of argon. The flask was
charged with 7 (1.01 g, 2.04 mmol) dissolved in hot,
anhydrous 1,4-dioxane (70 ml). To the hot solution was
added 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)
(3.65 g, 2.14 mmol). Upon addition, the color of the reac-
tion immediately became brown-red. The reaction was
refluxed for a period of 24 h. The reaction was poured into
100 mL of a saturated Na2CO3 solution. This was warmed
to 65 ꢁC. The mixture was extracted with CH2Cl2
(100 mL · 3) and was washed with saturated NaHCO3
(100 mL), distilled water (100 mL), and brine (100 mL).
The organic layer was collected and was dried over
Na2SO4. Filtration, followed by removal of the solvent
afforded the crude product as a tan-colored solid. This
was dissolved in dichloromethane and was chromato-
graphed using silica gel with CH2Cl2/hexane (1/3, v/v) as
an eluent. The appropriate fractions were combined, and
the solvent was removed under reduced pressure. The gray
solid was then dissolved in methylene chloride and was
crystallized by the addition of hexane to afford colorless
˚
˚
1.873 A and Co(2)–O bond length 1.925 A are significantly
shorter than those reported for Co(OAc)2(imid)2 [1.984(1)
˚
˚
A] [24] and Co(OAc)2(2-Me-imid)2 [2.098(1) A] [24] and
are comparable to those of [Co{O(Ox)}2] (1.9052 A). The
average Co(1)–N bond length 1.919 A and Co(2)–N bond
length 1.998 A are also shorter than those observed for
˚
˚
˚
˚
Co(OAc)2(imid)2 [2.0135(1) A] and Co(OAc)2(2-Me-
imid)2 [2.062(3)]. The overall dimension of the rectangle,
as defined by the front dibenzoacridine corners, is 23.5 ·
˚
6.2 A. No solvent molecules were not located in the cavity.
Cobalt oxazoline complex 17 shows a molecular order
dominated by edge-to-face interactions, leading to a her-
ringbone arrangement with no p-stacking (Fig. 3b).
3. Conclusion
1
crystals. Yield: 67%. m.p. = 347 ꢁC. H NMR (300 MHz,
Two rigid spacer-chelators bearing salen and oxazoline
unit were prepared. The molecular clips were found to be
effective ones to assemble metal acetates such as cobalt
and zinc. Supramolecular rectangles (12–13 and 16–17)
were readily prepared via self-assembly. X-ray crystallogra-
phy, NMR, and mass spectral data unambiguously estab-
lished the proposed structure. Work will involve the
binding of guest molecules and the study of catalysis with
use of the cofacial binuclear Zn and Co complexes.
CDCl3): d 9.88 (s, 2H), 7.84 (d, 2H, J = 8.7 Hz), 7.75 (d,
2H, J = 8.7 Hz), 7.66 (d, 2H, J = 9.3 Hz), 7.63 (s, 1H),
7.61 (d, 2H, J = 9.3 Hz), 7.30 (s, 2H), 1.42 (s, 18H).
13C{1H} NMR (75.4 MHz, CDCl3): d 151.19, 147.78,
144.66, 135.22, 133.43, 132.33, 129.57, 128.84, 128.16,
127.05, 126.16, 125.46, 124.76, 124.44, 121.72, 35.21,
31.73. Anal. Calc. for C35H31NBr2: C, 67.21; H, 5.00.
Found: C, 66.84; H, 4.92%.
4.3. Synthesis of 2,12-bis(trimethylsilylethynyl)-[7-(3,5-di-
tert-butylphenyl)dibenzo-[c, h]acridine]
4. Experimental section
4.1. General procedures
To a mixture of 8 (0.63 g, 1.01 mmol) and tetrakis(tri-
phenylphosphine)palladium (0.12 g, 0.10 mmol) and cop-
per(I) iodide (0.008 g, 0.04 mmol) in triethylamine
(40 mL) are added trimethylsilylacetylene (0.43 mL,
3.03 mmol). The reaction mixture is stirred at 80 ꢁC for
36 h under nitrogen. Then the solvent is removed under
reduced pressure. The residue is extracted with diethyl
ether and purified by chromatography on silica gel using
dichloromethane/hexane (1:3, v/v) as an eluent to afford
0.46 g of product. Yield: 88%. m.p. = 61 ꢁC. 1H NMR
(300 MHz, CDCl3): d 10.01 (s, 2H), 7.85 (m, 4H), 7.69
(d, 2H, J = 9.3 Hz), 7.65 (s, 1H), 7.63 (d, 2H,
J = 9.3 Hz), 7.32 (s, 2H), 1.43 (s, 18H), 0.41 (s, 18H).
13C{1H} NMR (75.4 MHz, CDCl3): d 151.13, 147.58,
All experiments were performed under a nitrogen atmo-
sphere in a Vacuum Atmospheres drybox or by standard
Schlenk techniques. 1,4-Dioxane, THF, toluene, ether,
and hexane were distilled from sodium and benzophenone.
Dichloromethane, MeOH, and EtOH were distilled under
nitrogen from P2O5. The H and 13C NMR spectra were
1
recorded on a Varian Mercury 300 spectrometer operating
at 300.00 and 75.44 MHz, respectively. IR spectra were
recorded on a Biorad FTS-165 spectrometer. MALDI-
MS specta were recorded on a Voyager-DE STR MALDI
TOF mass spectrometer. Elemental analyses were per-
formed with a Carlo Elba Instruments CHNS-O EA 1108

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D. Kim et al. / Journal of Organometallic Chemistry 691 (2006) 5946–5954
145.25, 135.37, 133.42, 131.84, 129.89, 127.78, 127.02,
125.42, 124.69, 124.31, 124.13, 122.17, 121.71, 106.04,
95.28, 35.21, 31.71, 0.32. Anal. Calc. for C45H49NSi2: C,
81.89; H, 7.48. Found: C, 80.11; H, 7.40%.
(30 mL). The organic layer was separated, and the aque-
ous layer was extracted with Et2O (2 · 20 mL). The com-
bined organic layers were washed with brine, and dried
over Na2SO4. The product was recrystallized by hexane
to afford a white solid. Yield: 97%. m.p. = 164 ꢁC. 1H
NMR (300 MHz, CDCl3): d 14.17 (s, 2H), 10.01 (s,
2H), 8.41, (s, 2H), 7.89 (m, 4H), 7.70 (d, 2H,
J = 9.3 Hz), 7.64 (s, 1H), 7.62 (d, 2H, J = 9.3 Hz), 7.58
(s, 2H), 7.47 (s, 2H), 7.32 (s, 2H), 3.93 (m, 2H, cyclo-
hexyl), 2.32 (m, 2H, cyclohexyl), 1.91 (m, 2H, cyclohexyl),
1.45 (s, 18H), 1.42 (s, 18H), 1.64–1.25 (m, 4H, cyclo-
hexyl). 13C{1H} NMR (75.4 MHz, CDCl3): d 161.25,
151.09,147.73, 14.29, 138.25, 135.49, 133.98, 133.12,
132.55, 132.03, 131.78, 129.86, 128.01, 127.21, 125.69,
124.83, 124.36, 122.92, 122.28, 120.87, 118.55, 112.74,
90.38, 88.40, 35.14, 31.68, 29.89, 29.55, 22.87, 14.22,
1.12. IR (KBr pellet: cmꢀ1): 1630 (v(C@N)). MALDI-
TOF-MS: m/z = 946.36 (M+H)+ calcd 946.52. Anal.
Calc. for C67H67N3O2: C, 85.04; H, 7.14. Found: C,
85.64; H, 7.02%.
4.4. Synthesis of 2,12-diethynyl-[7-(3,5-di-tert-
butylphenyl)dibenzo[c,h]acridine] (9)
A catalytic amount of 1 M NaOH solution was added to a
stirred solution of 2,12-bis(trimethylsilylethynyl)-[7-(3,5-di-
tert-butylphenyl)dibenzo[c,h]acridine] (0.44 g, 0.86 mmol)
in a mixture of THF (20 mL) and methanol (20 mL), After
complete consumption of the starting material, the reaction
mixture was dried and extracted with dichloromethane and
washed with H2O. The organic phase was dried over MgSO4,
and the crude product was purified by chromatography on
silica gel using dichloromethane/hexane (1:3, v/v) as an elu-
ent to afford 0.54 g of product. Yield: 96%. m.p. = 195 ꢁC.
1H NMR (300 MHz, CDCl3): d 9.96 (s, 2H), 7.85 (m, 4H),
7.68 (d, 2H, J = 9.3 Hz), 7.63 (s, 1H), 7.62 (d, 2H,
J = 9.3 Hz), 7.30 (s, 2H), 3.34 (s, 2H), 1.41 (s, 18H).
13C{1H} NMR (75.4 MHz, CDCl3): d 151.12, 147.64,
145.16, 135.30, 133.57, 132.13, 131.81, 129.85, 127.86,
126.99, 125.41, 124.70, 124.30, 122.13, 120.73, 84.91, 84.43,
35.18, 31.61. Anal. Calc. for C39H33N: C, 90.83; H, 6.45.
Found: C, 90.22; H, 6.38%.
4.7. Preparation of 12
A
degassed solution of Co(OAc)2 Æ 4H2O (0.11 g,
0.436 mmol) in MeOH (20 mL) was added to a degassed
solution of ligand 11 (0.34 g, 0.18 mmol) in toluene
(8 mL) via cannula under N2. The resulting mixture was
stirred under N2 for 8 h. The mixture was concentrated
under reduced pressure and extracted with CH2Cl2 and
washed with H2O. The organic phase was dried over
MgSO4. The crude product was purified by chromatogra-
phy on silica gel using dichloromethane/hexane (1:3, v/v)
as an eluent to afford 0.34 g of product. Yield: 97%.
m.p. > 400 ꢁC. IR (KBr pellet: cmꢀ1): 1601 (v(C@N)).
4.5. Synthesis of 2,12-bis(3-tert-butyl-4-hydroxy-5-
formylphenylethynyl)-[7-(3,5-di-tert-
butylphenyl)dibenzo[c,h]acridine] (10)
This compound was prepared with 3-tert-butyl-2-
hydroxy-5-iodobenzaldehyde using the same procedure as
that described for 2,12-bis(trimethylsilylethynyl)-[7-(3,5-di-
tert-butylphenyl)dibenzo[c,h]acridine] (reaction condition:
60 ꢁC, 36 h). Yield: 87%. m.p. = 287 ꢁC. 1H NMR
(300 MHz, CDCl3): d 11.88 (s, 2H), 10.06 (s, 2H), 9.61 (s,
2H), 7.89 (m, 4H), 7.75 (s, 4H), 7.69 (d, 2H, J = 9.3 Hz),
7.67 (s, 1H), 7.63 (d, 2H, J = 9.3 Hz), 7.32 (s, 2H), 1.43 (s,
18H), 1.37 (s, 18H). 13C{1H} NMR (75.4 MHz, CDCl3): d
196.59, 161.36, 151.16, 147.76, 145.25, 138.96, 137.91,
136.78, 135.65, 135.34, 134.31, 133.32, 132.02, 129.92,
128.31, 127.97, 125.46, 124.67, 124.40, 121.77, 120.56, 118.98,
114.50, 89.49, 35.21, 35.06, 30.34, 29.25. MALDI-TOF-
MS: m/z = 868.40 (M+H)+ calcd 868.43. Anal. Calc. for
C61H57NO4: C, 84.40; H, 6.62. Found: C, 83.99; H, 6.54%.
MALDI-TOF-MS:
m/z = 2007.07
(M+H)+
calcd
2006.89. Anal. Calc. for C134H130N6O4Co2: C, 80.22; H,
6.53. Found: C, 78.76; H, 6.41%.
4.8. Preparation of 13
This compound was prepared with Zn(OAc)2 Æ 2H2O
and EtOH using the same procedure as that described for
12. Yield: 92%. m.p. > 400 ꢁC. 1H NMR (300 MHz,
CDCl3): d 10.07 (s, 2H), 10.05 (s, 2H), 8.46 (s, 2H), 8.44
(s, 2H), 7.97 ꢁ 7.89 (m, 8H), 7.74 ꢁ 7.50 (m, 14H),
7.35 ꢁ 7.17 (m, 8H), 3.99 (m, 2H, cyclohexyl), 3.46 (m,
2H, cyclohexyl), 2.40 (m, 2H, cyclohexyl), 2.15 ꢁ 1.97 (m,
6H, cyclohexyl), 1.67 ꢁ 1.19 (m, 8H, cyclohexyl), 1.46 (s,
18H), 1.44 (s, 36H), 1.42 (s, 18H). 13C{1H} NMR
(75.4 MHz, CDCl3): d 172.81, 171.00, 168.39, 151.13,
147.53, 143.30, 142.83, 139.50, 137.90, 135.49, 133.07,
132.82, 132.07, 131.70, 131.17, 129.18, 128.72, 128.37,
127.92, 127.08, 125.44, 125.13, 124.37, 122.72, 122.56,
118.32, 118.06, 108.89, 108.74, 90.99, 90.74, 88.20, 87.72,
72.29, 35.64, 35.42, 35.22, 31.72, 29.45, 29.35, 21.59, 1.17.
IR (KBr pellet: cmꢀ1): 1598 (v(C@N)). MALDI-TOF-
MS: m/z = 2018.95 (M+H)+ calcd 2018.87. Anal. Calc.
4.6. Preparation of 11
To a solution of K2CO3 (0.61 g, 4.41 mmol) and (R,R)-
diaminocyclohexane tartrate salt (0.06 g, 0.23 mmol) in
H2O (30 mL) was added THF (12 mL), and the solution
was heated to reflux. A solution of 10 in THF (7 mL)
was added dropwise over 30 min. The addition funnel
was washed with THF (3 mL) and the reaction was stirred
at reflux for 8 h. After the solution was cooled to room
temperature, the solution was poured into Et2O

D. Kim et al. / Journal of Organometallic Chemistry 691 (2006) 5946–5954
5953
for C134H130N6O4Zn2: C, 79.70; H, 6.49. Found: C, 79.13;
H, 6.30%.
C122H106N6O8Zn2: C, 76.52; H, 5.58. Found: C, 76.22; H,
5.41%.
4.9. Synthesis of 2-(4,4-dimethyloxazolin-2-yl)-4-
iodophenol (14)
4.12. Preparation of 17
This compound was prepared using the same procedure
as that described for 12. Yield: 84%. m.p. > 400 ꢁC. Anal.
Calc. for C122H106N6O8Co2: C, 77.04; H, 5.62. Found: C,
75.68; H, 5.55%.
To a strirred solution of 5-iodosalicylic acid (5.28 g,
20.0 mmol),
2-amino-2-methyl-1-propanol
(1.91 mL,
20.0 mmol), PPh3 (15.74 g, 60.0 mmol), NEt3 (8.32 mL,
60.0 mmol) in CH2Cl2 (100 mL) was added CCl4
(19.30 ml, 200 mmol) via cannula for 8 h at 0 ꢁC. The
resulting solution was stirred at 50 ꢁC for an additional
12 h. The reaction mixture was allowed to cool to room
temperature and was dried in vacuo. The crude product
was purified by chromatography on silica gel using ben-
zene/hexane (1:1, v/v) as an eluent to give pale yellow oil.
Yield: 90%. 1H NMR (300 MHz, CDCl3): d 12.20 (s,
1H), 7.90 (s, 1H), 7.57 (d, 1H, J = 9.0 Hz), 6.76 (d, 1H,
J = 9.0 Hz), 4.06 (s, 2H), 1.36 (s, 6H). 13C{1H} NMR
(75.4 MHz, CDCl3): d 162.34, 159.50, 141.52, 136.20,
119.06, 113.13, 79.38, 67.24, 28.45. Anal. Calc. for
C11H12NO2I: C, 41.66; H, 3.81. Found: C, 41.08; H, 3.62%.
4.13. X-ray crystallography
Suitable crystals of 12 and 17 were grown by THF/hex-
ane. All X-ray intensity data of compounds 12 and 17 were
collected on a Bruker SMART 1000 CCD diffractometer
[25] with graphite monochromated Mo Ka radiation
˚
(k = 0.7107 A). The collected data were processed for inte-
gration; an empirical absorption correction was made on
the basis of the symmetry-equivalent reflection intensities
(SADABS) [26]. Structures were solved by direct methods
and refined by full-matrix least-squares procedures against
F2 using SHELXL97 [27].All non-hydrogen atoms in com-
pounds 12 and 17 were refined anisotropically. All hydro-
gen atoms were included in the calculated positions.
4.10. Synthesis of 2,12-bis[3-(4,4-dimethyloxazolin-2-yl)-
4-hydroxyphenylethynyl]-[7-(3,5-di-tert-
butylphenyl)dibenzo[c,h]acridine] (15)
Acknowledgements
This compound was prepared using the same procedure
as that described for 10. Yield: 86%. m.p. = 246 ꢁC. H
This work was supported by the KOSEF through Na-
tional Research Laboratory (NRL 2005) program awarded
to J.K.
1
NMR (300 MHz, CDCl3): d 12.53 (s, 2H), 10.04 (s, 2H),
8.04 (s, 2H), 7.88 (m, 4H), 7.71 (d, 2H, J = 8.4 Hz), 7.68
(d, 2H, J = 9.3 Hz), 7.66 (s, 1H), 7.64 (d, 2H,
J = 9.3 Hz), 7.33 (s, 2H), 7.03 (d, 2H, J = 8.4 Hz), 3.97
(s, 4H), 1.43 (s, 18H), 1.40 (s, 12H). 13C{1H} NMR
(75.4 MHz, CDCl3): d 163.14, 160.06, 151.05, 147.45,
145.20, 136.57, 135.39, 133.02, 131.98, 131.80, 131.42,
128.94, 127.87, 126.96, 125.04, 124.28, 122.11, 121.99,
117.11, 113.84, 111.24, 90.21, 89.27, 78.45, 67.27, 65.33,
35.14, 31.66, 28.55. IR (KBr pellet: cmꢀ1): 1624
(v(C@N)). MALDI-TOF-MS: m/z = 894.37 (M+H)+ calcd
894.42. Anal. Calc. for C61H55N3O4: C, 81.94; H, 6.20.
Found: C, 81.62; H, 6.07%.
Appendix A. Supplementary data
CCDC 617645 and 617646 contains the supplementary
crystallographic data 12 and 17. These data can be
obtained free of charge via http://www.ccdc.ac.uk/conts/
retrieving.html, or from the Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK;
fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.
cam.ac.uk.
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3
˚
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c = 20.720(3) A, a = 90ꢁ, b = 90ꢁ, c = 90ꢁ, V = 8869(2) A , Z = 2,
¨
¨
q
calc= 0.859 g cmꢀ3, k(Mo Ka) = 0.71073 A, 2hmax = 56.30ꢁ, index
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¨
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,
65717 measured reflection, 22037 independent reflection,
R1 = 0.1650, wR2 = 0.3734 (I > 2r (I)), GOF = 1.098.
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C122H106Co2N6O8 Æ (C4H8O) Æ 3 (H2O),
Mr = 2022.09, monoclinic, space group Pc, a = 16.7029(14),
˚
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3
90ꢁ, V = 7451.7(11) A , Z = 2,
q
calc = 0.904 g cmꢀ3
,
k(Mo
˚
˚
Ka) = 0.71073 A, 2hmax = 56.64ꢁ, index range: ꢀ22 6 h 6 22,
ꢀ27 6 k 6 27, ꢀ29 6 l 6 29, l = 0.270 mmꢀ1
, 76144 measured
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(I > 2r (I)), GOF = 1.076.
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