New diformyldihydroxyaromatic precursors for luminescent Schiff base macrocycles: Synthesis, characterization, and condensation studies

Article abstract of DOI:10.1139/V07-136

With the goal of preparing luminescent, fully conjugated Schiff base macrocycles, a series of precursors based on benzene, phenanthrene, and triphenylene with formylhydroxy functionalization have been prepared and characterized. The condensation of these compounds with substituted phenylenediamines to afford conjugated [2+2] or [3+3] Schiff base macrocycle has been investigated. Although the [3+3] Schiff base .macrocycles could not be isolated, two new soluble and luminescent [2+2] Schiff base macrocycles with N₂O₂ binding pockets have been prepared and characterized.

Full text of DOI:10.1139/V07-136

50
New diformyldihydroxyaromatic precursors for
luminescent Schiff base macrocycles: Synthesis,
characterization, and condensation studies
Britta N. Boden, Amir Abdolmaleki, Cecily T.-Z. Ma, and Mark J. MacLachlan
Abstract: With the goal of preparing luminescent, fully conjugated Schiff base macrocycles, a series of precursors
based on benzene, phenanthrene, and triphenylene with formylhydroxy functionalization have been prepared and char-
acterized. The condensation of these compounds with substituted phenylenediamines to afford conjugated [2+2] or
[3+3] Schiff base macrocycle has been investigated. Although the [3+3] Schiff base macrocycles could not be isolated,
two new soluble and luminescent [2+2] Schiff base macrocycles with N2O2 binding pockets have been prepared and
characterized.
Key words: Schiff base, macrocycle, condensation, salicylaldehyde, conjugated.
Résumé : Afin de pouvoir obtenir des bases de Schiff macrocycliques complètement conjuguées et luminescentes, on a
préparé et caractérisé une série de précurseurs à base de benzène, de phénanthrène et de triphénylène portant des grou-
pes hydroxyle et formyle. On a ensuite étudié la condensation de ces composés avec des phénylènediamines substituées
qui peuvent conduire à des bases de Schiff macrocycliques avec conjugaison [2+2] ou [3+3]. Même si on n’a pas pu
isoler les bases de Schiff macrocycliques [3+3], on a pu préparer et caractériser deux nouvelles bases de Schiff macro-
cycliques [2+2], solubles et luminescentes, comportant des poches de fixation du N2O2.
Mots-clés : base de Schiff, macrocycle, condensation, salicylaldéhyde, conjugué.
[Traduit par la Rédaction] Boden et al. 64
Introduction
onal [6+6] Schiff base macrocycles, respectively, and 5 (35)
is expected to form [2+2] Schiff base macrocycles. Only a
few other bis(formylhydroxy) compounds have been ex-
plored as precursors for Schiff base macrocycles (36–40).
Expanding the number of bis(formylhydroxy) compounds
available will open up avenues to explore macrocycles with
new electronic, optical, and coordinating properties.
In this paper, we significantly expand the library of dihy-
droxydiformyl compounds predisposed for [2+2] and [3+3]
Schiff base macrocycles. In an effort to obtain fully conju-
gated, luminescent macrocycles, we have prepared the first
phenanthrene and triphenylene precursors with bis(formyl-
hydroxy) functionality. Phenanthrene and triphenylene have
received very little attention for incorporation into
macrocycles (41, 42), yet they may have a large effect on the
ring size and electronic or optical properties of the products.
In addition, we have prepared new conjugated m-diethynyl-
benzene precursors for the preparation of [2+2] Schiff base
macrocycles. We report on the optical properties of the novel
diamond-shaped macrocycles.
Schiff base macrocycles formed from the condensation of
diamines and dialdehydes are attractive ligands for
multimetallic complexes (1–20). 2,6-Diformylphenol 1 and
its analogues condense with diamine compounds in a 2:2 ra-
tio to form compartmental ligands (Robson macrocycles 2)
(21–25) (Chart 1). Bimetallic complexes formed in the inte-
rior of this macrocycle are of interest for studying magnetic
and electronic interactions between metal centres, and may
serve as models for the active sites of enzymes (26, 27).
The hydroxyl group adjacent to the formyl moiety in the
precursor is important for producing an N2O2 chelate and for
stabilizing the imine in the metal-free macrocycle. While a
vast assortment of diamines is available for incorporation
into Schiff base macrocycles, much less attention has been
placed on the bis(formylhydroxy) precursor development.
By varying the geometry and structure of this component,
one may access novel macrocycles with different sizes,
shapes, and number of metal-binding sites (28–30). For ex-
ample, condensation of compounds 3 (31–33) and 4 (34)
with o-phenylenediamines gives triangular [3+3] and hexag-
Experimental
Received 4 July 2007. Accepted 5 November 2007. Published
on the NRC Research Press Web site at canjchem.nrc.ca on
13 December 2008.
General
Tetrahydrofuran (THF) was distilled over Na and benzo-
phenone under N2. Triethylamine was distilled over NaOH
under N2. Stilbene 6 (43), 3,6-dimethoxyphenanthrene 7 (44),
3,6-dimethoxyphenanthrene-9,10-quinone 10 (45), 1,2-
dibromo-4,5-dihexylbenzene 15 (46), 4-methoxyphenyl-
boronic acid 16 (47), 1,3-diethynylbenzene 24 (48), 2,6-
diethynylpyridine 25 (49), 1,2-diamino-4,5-dialkoxy-
B.N. Boden, A. Abdolmaleki, C.T.L. Ma, and M.J.
MacLachlan.1 Department of Chemistry, University of
British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1,
Canada.
1Corresponding author (email: mmaclach@chem.ubc.ca).
Can. J. Chem. 86: 50–64 (2008)
doi:10.1139/V07-136
© 2007 NRC Canada

Boden et al.
51
Chart 1.
solid. The product was chromatographed over silica with
DCM and recrystallized from DCM to obtain 0.150 g of yel-
low solid (17% yield).
OH
O
O
HO
OH
O
O
Data for 8
Mp 280 °C dec. UV–vis (CH2Cl2): λmax (⑀) = 281 (5.6 ×
104), 338 (2.5 × 104), 440 (2.2 × 103) nm (L mol–1cm–1). IR
(KBr): ν = 2947, 2862, 1681, 1615, 1502, 1457, 1406, 1369,
1265, 1220, 1181, 1136, 1109, 1017, 970, 842, 655 cm–1. 1H
NMR (300 MHz, CDCl3, 25 °C) δ: 10.63 (s, 2H, CHO),
8.36 (s, 2H, aromatic CH), 7.92 (s, 2H, aromatic CH), 7.65
(s, 2H, aromatic CH), 4.17 (s, 6H, OCH3) ppm. 13C NMR
(75.5 MHz, CDCl3, 25 °C) δ: 189.7, 159.0, 134.3, 130.6,
127.3, 126.1, 126.0, 103.8, 55.9 ppm. ESI-MS: m/z = 295
([M + H]+). Anal. calcd. for C18H14O4·0.5 H2O: C, 71.28; H,
4.98. Found: C, 71.35; H, 4.80.
1
3
HO
OH
O
O
4
N
N
OH
OH
N
N
O
OH OH
O
Synthesis of 2,7-diformyl-3,6-dihydroxyphenanthrene (9)
To an ice-cooled solution of compound 8 (0.413 g,
1.40 mmol) in DCM was added BBr3 (1 mL, 10.6 mmol).
After stirring overnight, the solution was poured into
200 mL of ice water to obtain an orange solid. The solid was
filtered, and the remaining aq. solution was extracted with
DCM. The organic layer was dried and combined with the
solid. After flashing the product through silica with DCM,
0.268 g (1.01 mmol) of orange crystals were obtained (72%
yield).
2
5
benzenes 28 (50), and BOC-protected phenylenediamine 32
(51) were prepared according to literature procedures.
Pd(PPh3)4 was obtained from Strem Chemicals, Inc.
Deuterated solvents were obtained from Cambridge Isotope
Laboratories, Inc. All other chemicals were purchased from
Aldrich, TCI, or Fisher and used as received. All reactions
1
were carried out under nitrogen unless otherwise noted. H
Data for 9
NMR (300 or 400 MHz) and 13C NMR (75.5 or 100.7 MHz)
spectra were recorded on Bruker Avance 300 or Bruker
Avance 400 spectrometers and were referenced internally to
residual protonated solvent. Infrared spectra were obtained
as KBr discs or on NaCl plates with a Bomem MB-100
spectrometer or a Nicolet 4700 FTIR spectrometer. UV–vis
spectra were obtained on a Varian Cary 5000 UV–vis/near
IR spectrometer using a 1 cm cuvette. Fluorescence spectra
were obtained on a Photon Technology Intl. QuantaMaster
fluorimeter. Matrix assisted laser desorption/ioniza-
tion(MALDI) mass spectra were obtained on a Bruker Biflex
IV time-of-flight (TOF) mass spectrometer equipped with a
MALDI ion source. Electrospray ionization (ESI) mass
spectra were obtained on a Micromass LCT time-of-flight
(TOF) mass spectrometer equipped with an electrospray ion
source. Samples were analyzed in methanol:dichloromethane
at 1 µmol/L. EI spectra were obtained with a double focus-
ing mass spectrometer (Kratos MS-50) coupled with a
MASPEC data system with EI operating conditions of:
source temperatures 120–220 °C and ionization energy
70 eV. Elemental analyses were obtained at the UBC
Microanalytical facility. Melting points were recorded on a
Fisher John’s melting point apparatus.
Mp > 300 °C. UV–vis (CH2Cl2): λmax (⑀) = 284, 304, 326,
465 nm. IR (KBr): ν = 3449, 3253, 3017, 2884, 1652, 1530,
1
1338, 1205, 1157, 1106, 899 cm–1. H NMR (300 MHz,
DMSO-d6, 25 °C) δ: 10.96 (s, 2H, OH), 10.46 (s, 2H, CHO),
8.29 (s, 2H, aromatic CH), 7.99 (s, 2H, aromatic CH), 7.67
(s, 2H, aromatic CH) ppm. 13C NMR (75.5 MHz, DMSO-d6,
25 °C) δ: 191.3, 157.6, 134.0, 133.0, 130.6, 128.2, 125.9,
125.1, 124.2, 109.2 ppm. EI-MS: m/z = 266 (M+). Anal.
calcd. for C16H10O4: C, 72.18; H, 3.79. Found: C, 72.05; H,
4.00.
Synthesis of 2,7-dibromo-3,6-dimethoxyphenanthrene-
9,10-quinone (11)
To a solution of 3,6-dimethoxy-9,10-phenanthrenequinone
10 (1.090 g, 4.06 mmol) in 25 mL each DCM and MeCN
was added Br2 (1 mL, 19.5 mmol) and FeCl3 (1.317 g,
8.12 mmol). The solution was heated to reflux until an or-
ange solid precipitated. After filtration of the solid, the fil-
trate was poured in H2O and extracted with DCM. The
solvent was removed under vacuum until further precipita-
tion. Both solids were combined and recrystallized from
DCM to yield 1.298 g (3.05 mmol, 75%). The product was
sometimes chromatographed on silica with DCM.
Data for 11
Synthesis of 2,7-diformyl-3,6-dimethoxyphenanthrene
(8)
Mp > 300 °C. UV–vis (CH2Cl2): λmax (⑀) = 247 (1.6 ×
104), 297 (5.8 × 104), 344 (1.3 × 104) nm (L mol–1cm–1). IR
(KBr): ν = 3448, 2946, 1670, 1578, 1545, 1436, 1333, 1312,
1274, 1262, 1203, 1040, 854, 696, 678 cm–1. 1H NMR
(300 MHz, CDCl3, 25 °C) δ: 8.33 (s, 2H, aromatic CH),
7.22 (s, 2H, aromatic CH), 4.11 (s, 6H, OCH3) ppm; 13C
NMR (100.7 MHz, CDCl3, 25 °C) δ: 177.7, 162.0, 136.5,
136.1, 125.9, 114.7, 105.9, 57.0 ppm. EI-MS: m/z = 426
3,6-Dimethoxyphenanthrene 7 (0.718 g, 3.01 mmol) was
dissolved in 20 mL THF. BuLi (6.1 mL, 1.6 mol/L) was
added, and the solution was stirred for 30 min, after which
anhyd. DMF (0.77 mL, 9.98 mmol) was added. The reaction
solution was poured into aq. HCl and extracted with di-
chloromethane (DCM). After drying over MgSO4, the sol-
vent was removed by rotary evaporation to reveal an orange
© 2007 NRC Canada

52
Can. J. Chem. Vol. 86, 2008
(M+). Anal. calcd. for C16H10O4Br2: C, 45.10; H, 2.37.
Found: C, 44.95; H, 2.66.
was dissolved in THF to make an initially purple solution,
which slowly became yellow upon standing. The solvent
was removed to give a brown solid (14). We believe the ini-
tially obtained solid is a tautomer or partially reduced form
of 14, but it was not possible to obtain a pure sample of the
purple intermediate.
Synthesis of 2,7-dibromo-3,6,9,10-tetramethoxy-
phenanthrene (12)
Compound 11 (0.567 g, 1.33 mmol), Bu4NBr (0.113 g,
0.351 mmol), Na2S2O4 (0.610 g, 3.50 mmol), THF (50 mL)
and H2O (50 mL) were combined in a round-bottomed flask
and stirred for 10 min, after which dimethyl sulfate (3 mL,
31.7 mmol) was added, followed by aq. sodium hydroxide
(2 mL, 14 mol/L). After stirring 1 h, the aq. layer was sepa-
rated and extracted with EtOAc (3 × 50 mL). The combined
organic layers were washed with water (3 × 50 mL), NH4OH
solution (2 × 50 mL), and brine (1 × 50 mL). The organic
layer was dried with MgSO4, filtered, and the solvents were
removed under vacuum, resulting in a brown solid. Washing
the product with MeOH gave an orange solid. Additional
impurities were removed by flashing the product through sil-
ica with a 1:1 mixture of hexanes and DCM, followed by
recrystallization from DCM. Yield: 0.473 g, 1.0 mmol, 78%.
Data for 14
Mp > 300 °C. UV–vis (DMSO): λmax (⑀) = 314 nm. IR
(KBr): ν = 3422, 2925, 2856, 1692, 1665, 1613, 1551, 1361,
1320, 1252, 1197, 1154, 947, 789, 652 cm–1. 1H NMR
(300 MHz, DMSO-d6, 25 °C) δ: 12.12 (s, 2H, OH), 10.33 (s,
2H CHO), 8.34 (s, 2H, aromatic CH), 7.59 (s, 2H, aromatic
CH) ppm. EI-MS: m/z = 296 (M+). HR-MS calcd. for
C16H8O6: 296.03209. Found: 296.03142.
′′
′′
Synthesis of 4′,5′-dihexyl-4,4 -dimethoxy-1,1′:2′,1 -
terphenyl (17)
A
mixture of 1,2-dibromo-4,5-dihexylbenzene 15
(1.049 g, 2.59 mmol), 4-methoxyphenylboronic acid 16
(0.971 g, 6.39 mmol), sodium carbonate (0.971 g,
9.16 mmol), and tetrakis(triphenylphosphine)palladium(0)
(0.050 g, 0.043 mmol) was stirred under reflux in a mixture
of toluene (18 mL), EtOH (18 mL), and water (6 mL) for
4 h. The solution was poured into water and extracted with
DCM (3 × 100 mL). After drying with MgSO4 and evaporat-
ing the solvent, a brown oil was obtained and purified by
chromatography in 3:1 hexanes/DCM. Additional impurities
were crystallized out from EtOH. The product was a color-
less oil. Yield: 0.732 g, 1.60 mmol, 62%.
Data for 12
Mp 217–218 °C. UV–vis (CH2Cl2): λmax (⑀) = 264 (5.3 ×
104), 225 (3.8 × 104), 384 (1.0 × 103) nm (L mol–1cm–1). IR
(KBr): ν = 3448, 2933, 1597, 1491, 1451, 1432, 1364, 1245,
1
1074, 1056, 993, 676 cm–1. H NMR (400 MHz, CDCl3,
25 °C) δ: 8.38 (s, 2H, aromatic CH), 7.77 (s, 2H, aromatic
CH), 4.09 (s, 6H, OCH3), 4.02 (s, 6H, OCH3) ppm. 13C
NMR (100.7 MHz, CDCl3, 25 °C) δ: 154.2, 142.1, 128.0,
127.5, 125.2, 114.1, 103.9, 61.3, 56.8 ppm. EI-MS: m/z =
456 (M+). Anal. calcd. for C18H16O4Br2: C, 47.40; H, 3.54.
Found: C, 47.2; H, 3.66.
Data for 17
UV–vis (CH2Cl2): λmax (⑀) = 251 (4.7 × 104) nm (L mol–
1cm–1). IR (KBr): ν = 2955, 2928, 2855, 1608, 1512, 1490,
1467, 1290, 1245, 1107, 1033, 831 cm–1. 1H NMR
(400 MHz, CDCl3, 25 °C) δ: 7.14 (s, 2H, aromatic CH),
7.06 (d, 4H, aromatic CH), 7.74 (d, 4H, aromatic CH), 3.76
(s, 6H, OCH3), 2.64 (m, 4H, CH2), 1.62 (m, 4H, hexyl
chain), 1.41 (m, 4H, hexyl chain), 1.33 (m, 8H, hexyl chain),
0.89 (t, 6H, hexyl CH3) ppm. 13C NMR (100.7 MHz, CDCl3,
25 °C) δ: 158.3, 139.8, 137.5, 134.5, 131.5, 131.1, 113.5,
55.4, 32.7, 32.0, 31.6, 29.8, 22.9, 14.3 ppm. EI-MS: m/z =
458 (M+). HR-MS calcd. for C32H42O2: 458.31848. Found:
458.31810.
Synthesis of 2,7-diformyl-3,6,9,10-tetramethoxy-
phenanthrene (13)
Compound 12 (0.373 g, 0.818 mmol) was dissolved in
18 mL THF and cooled to 0 °C. To the solution was added
BuLi (1.2 mL, 1.6 mol/L). After 10 min stirring, DMF
(0.3 mL, 3.87 mmol) was added. The solution was poured
into acidified H2O and extracted with DCM. Evaporation of
the solvent gave a yellow solid (0.188 g, 0.531 mmol, 65%
yield).
Data for 13
Mp 294 °C dec. UV–vis (CH2Cl2): λmax (⑀) = 287 (5.2 ×
104), 342 (2.0 × 104), 448 (2.0 × 103) nm (L mol–1cm–1). IR
(KBr): ν = 3448, 2935, 2858, 1686, 1610, 1491, 1452, 1429,
1358, 1278, 1249, 1205, 1145, 1128, 1014, 976, 570 cm–1.
1H NMR (300 MHz, CDCl3, 25 °C) δ: 10.62 (s, 2H, CHO),
8.68 (s, 2H, aromatic CH), 7.68 (s, 2H, aromatic CH), 4.15
(s, 6H, OCH3), 4.05 (s, 6H, OCH3) ppm. 13C NMR
(75.5 MHz, CDCl3, 25 °C) δ: 190.0, 158.8, 143.3, 132.6,
126.3, 125.3, 104.3, 61.4, 56.2 ppm. EI-MS: m/z = 354 (M+).
HR-MS calcd. for C20H18O6: 354.11034. Found: 354.11005.
Synthesis of 2,3-dihexyl-7,10-dimethoxytriphenylene (18)
Compound 17 (0.778 g, 1.69 mmol) and iodine (0.667 g,
2.6 mmol) were dissolved in 250 mL dry toluene. The solu-
tion was exposed to UV light for 72 h. Excess iodine was re-
moved by washing the solution with aq. NaSO3, and the
resulting organic layer was dried with MgSO4, and the sol-
vent was removed under vacuum. Recrystallization of the
product from EtOH afforded off-white crystals of 18, while
0.629 g of terphenyl 17 was recovered and reused in subse-
quent reactions. Yield: 0.098 g (0.215 mmol, 66% yield
based on recovered 17).
Synthesis of 2,7-diformyl-3,6-dihydroxyphenanthrene-
9,10-quinone (14)
Compound 13 was dissolved in 10 mL dry DCM and
cooled to 0 °C. To the solution was added BBr3. After stir-
ring overnight, the dark solution was poured into H2O to
precipitate a purple solid. After filtration, some of the solid
Data for 18
Mp 73–75 °C. UV–vis (CH2Cl2): λmax (⑀) = 262 (9.3 ×
104), 271 (1.2 × 105) nm (L mol–1cm–1). IR (KBr): ν = 2953,
2926, 2852, 1619, 1508, 1464, 1416, 1367, 1231, 1203,
© 2007 NRC Canada

Boden et al.
53
1178, 1050, 1027, 835, 812 cm–1. 1H NMR (400 MHz,
CDCl3, 25 °C) δ: 8.52 (d, 2H, aromatic CH), 8.24 (s, 2H, ar-
omatic CH), 7.92 (d, 2H, aromatic CH), 7.23 (dd, 2H, aro-
matic CH), 4.00 (s, 6H, OCH3), 2.80 (m, 4H, CH2), 1.71 (m,
4H, hexyl chain), 1.50 (m, 4H, hexyl chain), 1.24 (m, 8H,
hexyl chain), 0.92 (t, 6H, hexyl CH3) ppm. 13C NMR
(100.7 MHz, CDCl3, 25 °C) δ: 158.6, 139.6, 130.8, 127.1,
125.0, 124.5, 123.1, 115.6, 106.3, 55.7, 33.4, 32.1, 31.8,
29.8, 22.9, 14.4 ppm. EI-MS: m/z = 456 (M+). Anal. calcd.
for C32H40O2: C, 84.16; H, 8.83. Found: C, 84.32; H, 8.61.
14.4 ppm. EI-MS: m/z = 512 (M+). Anal. calcd. for
C34H40O4: C, 79.65; H, 7.86. Found: C, 79.52; H, 7.93.
Synthesis of 6,11-diformyl-2,3-dihexyl-7,10-
dihydroxytriphenylene (21)
To an ice-cooled solution of 20 (0.495 g, 0.965 mmol) in
dry DCM (50 mL), boron tribromide (2.2 mL, 23.3 mmol)
was added to produce a dark brown solution, which subse-
quently faded to orange. The solution was allowed to warm
to room temperature overnight, then was poured into ice wa-
ter (200 mL). After the mixture had warmed, it was filtered,
and the filtrate was extracted with CHCl3 (3 × 50 mL). The
filtered solid and organic layer from extraction were com-
bined, and the solvent was removed under vacuum. The resi-
due was passed through a plug of silica in CHCl3. After
removal of the solvent, the product was recrystallized from
CHCl3 to obtain 0.357 g (0.736 mmol, 76% yield) of a yel-
low solid.
Synthesis of 6,11-dibromo-2,3-dihexyl-7,10-
dimethoxytriphenylene (19)
To an ice-cooled solution of 18 (0.532 g, 1.16 mmol) in
DCM (20 mL), bromine (0.1 mL, 1.9 mmol) was added
dropwise. The solution was allowed to stir for 2 h. After
washing with aq. Na2S2O4, the organic layer was dried with
MgSO4, and the solvent was removed under vacuum.
Recrystallization from EtOH and DCM afforded white fi-
brous crystals. Yield: 0.563 g, 0.916 mmol, 79%.
Data for 21
Mp 260–262 °C. UV–vis (CH2Cl2): λmax (⑀) = 248 (3.5 ×
104), 274 (6.1 × 104), 393 (8.0 × 103) nm (L mol–1cm–1). IR
(KBr): ν = 3444, 2952, 2926, 2855, 1659, 1584, 1543, 1467,
Data for 19
Mp 166–168 °C. UV–vis (CH2Cl2): λmax (⑀) = 274 (1.6 ×
105) nm (L mol–1cm–1). IR (KBr): ν = 2956, 2926, 2853,
1600, 1494, 1464, 1401, 1252, 1201, 1059, 866, 830,
1
1341, 1230, 1184, 880, 826, 790, 725, 600 cm–1. H NMR
(400 MHz, CDCl3, 25 °C) δ: 10.68 (s, 2H, OH), 10.19 (s,
2H, CH=O), 8.71 (s, 2H, aromatic CH), 8.18 (s, 2H, aro-
matic CH), 7.96 (s, 2H, aromatic CH), 2.82 (m, 4H, CH2),
1.72 (m, 4H, hexyl chain), 1.49 (m, 4H, hexyl chain), 1.36
(m, 8H, hexyl chain), 0.91 (t, 6H, hexyl CH3) ppm. 13C
NMR (75.5 MHz, CDCl3, 25 °C) δ: 196.8, 158.7, 141.1,
135.4, 130.4, 126.4, 124.8, 123.1, 121.9, 112.1, 33.4, 33.0,
31.9, 29.8, 22.9, 14.4 ppm. EI-MS: m/z = 484 (M+). Anal.
calcd. for C32H36O4: C, 79.31; H, 7.49. Found: C, 79.06; H,
7.52.
1
701 cm–1. H NMR (400 MHz, CDCl3, 25 °C) δ: 8.71 (s,
2H, aromatic CH), 8.13 (s, 2H, aromatic CH), 7.76 (s, 2H,
aromatic CH), 4.11 (s, 6H, OCH3), 2.81 (m, 4H, CH2), 1.70
(m, 4H, hexyl chain), 1.47 (m, 4H, hexyl chain), 1.34 (m,
8H, hexyl chain), 0.91 (t, 6H, hexyl CH3) ppm. 13C NMR
(100.7 MHz, CDCl3, 25 °C) δ: 154.7, 140.7, 129.4, 128.6,
126.2, 125.7, 123.2, 114.0, 104.9, 56.7, 33.4, 32.0, 31.9,
29.8, 22.9, 14.4 ppm. EI-MS: m/z = 614 (M+). Anal. calcd.
for C32H38O2Br2: C, 62.55; H 6.23. Found: C, 62.70; H,
6.54.
Synthesis of 4-Iodosalicylaldehyde (23)
Synthesis of 6,11-diformyl-2,3-dihexyl-7,10-
Under a nitrogen atmosphere, dry paraformaldehyde
(4.05 g, 135 mmol) was added to a mixture of the 3-
iodophenol 22 (4.40 g, 20 mmol), anhyd. MgCl2 (2.86 g,
30 mmol), and anhyd. Et3N (10.5 mL) in dry MeCN
(100 mL). After heating the mixture to reflux for 2 h, the
mixture was cooled to RT, and 100 mL of 2 mol/L aq. HCl
was added. The product was extracted with 3 × 100 mL of
Et2O, dried over MgSO4, filtered, and dried by rotary evapo-
ration. The residue was dissolved in a mixture of 1:1
CH2Cl2/hexanes and was filtered through a short pad
(~5 cm) of SiO2 using the same solvent mixture as eluent.
Rotary evaporation of the filtered solution gave an off-white
solid. Recrystallization from hexanes gave white crystals of
23 (2.22 g, 9.0 mmol, 45%).
dimethoxytriphenylene (20)
To a solution of 19 (0.795 g, 1.29 mmol) in dry THF
(40 mL) cooled to –78 °C, 1.6 mol/L n-BuLi (4 mL,
6.4 mmol) was added to produce a milky white solution. Af-
ter 10 min, anhyd. DMF (0.8 mL, 10.3 mmol) was added to
form a pale yellow solution. The solution was warmed to
room temperature, then poured into aq. HCl (1 mol/L). Ex-
traction with DCM, drying with MgSO4, and evaporation of
the solvent afforded a brown oil. Yellow solid precipitated
out upon addition of EtOH. Yield: 0.534 g, 1.04 mmol, 81%.
Data for 20
Mp 165–167 °C. UV–vis (CH2Cl2): λmax (⑀) = 264 (7.0 ×
104), 279 (6.2 × 104), 384 (1.2 × 104) nm (L mol–1cm–1). IR
(KBr): ν = 2960, 2927, 2860, 1687, 1614, 1472, 1421, 1412,
1255, 1207, 1165, 1047, 869, 830 cm–1. 1H NMR (400 MHz,
CDCl3, 25 °C) δ: 10.60 (s, 2H, CH=O), 8.94 (s, 2H, aro-
matic CH), 8.22 (s, 2H, aromatic CH), 7.67 (s, 2H, aromatic
CH), 4.07 (s, 6H, OCH3), 2.79 (m, 4H, CH2), 1.68 (m, 4H,
hexyl chain), 1.48 (m, 4H, hexyl chain), 1.36 (m, 8H, hexyl
chain), 0.92 (t, 6H, hexyl CH3) ppm. 13C NMR (100.7 MHz,
CDCl3, 25 °C) δ: 190.0, 159.4, 141.2, 134.3, 126.9, 125.4,
125.2, 124.8, 123.5, 105.0, 55.9, 33.5, 32.1, 32.0, 29.9, 22.9,
Data for 23
Mp 91–92 °C (lit. 87 °C) (52). UV–vis (CH2Cl2): λmax (⑀) =
327 (5.32 × 103) nm (L mol–1cm–1). IR (KBr): ν = 3431,
2927, 2856, 1665, 1609, 1458, 1260, 1169, 891, 796, 752,
1
704 cm–1. H NMR (300 MHz, CDCl3) δ: 11.00 (s, 1H,
OH), 9.83 (s, 1H, CH=O), 7.41 (s, 1H, CH), 7.37 (dd, 3JHH
9.48 Hz, 1H, CH), 7.23 (d, JHH = 8.07 Hz, 1H, CH) ppm.
13C NMR (75.5 MHz, CDCl3) δ: 221.0, 196.0, 134.2, 129.4,
127.2, 105.1, 97.7 ppm. EI-MS: m/z = 247 (M+, 100%).
=
3
© 2007 NRC Canada

54
Can. J. Chem. Vol. 86, 2008
n
Anal. calcd. for C7H5IO2: C, 33.90; H, 2.03. Found: C,
34.11; H, 2.10.
Data obtained for filtrate when R = C8H17 (29c)
1H NMR (400 MHz, CDCl3, 25 °C) δ: 12.97, 10.61,
10.07, 10.05, 8.66, 8.01, 7.99, 7.82, 7.49, 6.80, 6.34, 3.95,
1.82–0.86 (hexyloxy chain) ppm. ESI-MS: m/z = 614 (M+,
1+1 fragment).
Synthesis of Compound 26
Under a nitrogen atmosphere, 1,3-diethynylbenzene 24
(0.254 g, 2.0 mmol), 4-iodosalicylaldehyde 23 (0.992 g,
4.0 mmol), Ph3P (0.015 g, 0.06 mmol), and trans-
[PdCl2(Ph3P)2] (0.06 g, 0.08 mmol) were dissolved in 25 mL
of anhyd. THF. Dry Et3N (2.3 mL) was added, turning the
solution from yellow to orange. After stirring for 20 min,
CuI (0.02 g, 0.10 mmol) was added, and the solution then
turned to dark brown. The solution was stirred overnight at
RT, then the yellow precipitate was isolated on a Büchner
funnel and washed with CH2Cl2/hexane (1:2). Yield: 0.549 g
(1.5 mmol, 75%) of yellow powder.
n
Data for solid obtained from reaction with R = C8H17
(29c)
1H NMR (400 MHz, CDCl3, 25 °C) δ: 13.00, 12.93,
10.63, 10.11, 10.09, 8.72, 8.52, 8.06, 8.03, 7.87, 7.51, 7.49,
6.83, 6.36, 3.95, 1.83–0.86 (hexyloxy chain) ppm. MALDI-
TOF: m/z = 1785 ([29c + H]+).
Attempted synthesis of macrocycle 30
Equimolar amounts of compound 21 and 1,2-diamino-4,5-
dialkoxybenzenes were combined in a Schlenk flask. Sol-
vent was added, and the resulting solution was heated to re-
flux. For specific conditions, see later. In each case, nearly
the same inseparable mixture was obtained as indicated by
1H NMR spectroscopy.
Data for 26
Mp > 250 °C dec. UV–vis (CH2Cl2): λmax (⑀) = 297 (3.24 ×
104), 331 (3.29 × 104) nm (L mol–1cm–1). IR (KBr): ν =
3430, 2958, 2926, 2855, 1664, 1609, 1224, 1168, 799,
1
704 cm–1. H NMR (300 MHz, DMSO-d6) δ: 10.98 (s, 2H,
Data for 30
OH), 10.28 (s, 2H, CH=O), 7.82 (s, 1H, CH), 7.68 (m, 4H,
1H NMR (300 MHz, CDCl3, 25 °C) δ: 14.84, 13.66,
13.21, 13.02, 12.35, 12.28, 12.06, 11.65, 9.2–6.3, 4.2–3.8,
2.9–2.7, 2.0–0.8 ppm. MALDI-TOF-MS: m/z = 1935 ([M +
H]+).
3
CH), 7.53 (t, JHH = 10.6 Hz, 1H, CH) 7.12–7.15 (m, 4H,
CH) ppm. 13C NMR (75.5 MHz, DMSO-d6) δ: 190.3, 160.4,
134.4, 132.3, 129.5, 129.1, 122.5, 122.3, 119.6, 91.3,
89.3 ppm. EI-MS: m/z = 366 (M+, 100%), 338 (85%). Anal.
calcd. for C24H14O4qH2O: C, 74.99; H, 4.20. Found: C,
75.28; H, 4.20.
Synthesis of compound 33
Compound 21 (0.058 g, 0.120 mmol) and p-anisidine 31
(0.46 g, 0.373 mmol) were combined in a flask and dis-
solved in dry THF to form a yellow solution. After refluxing
for 4 h, the solution was cooled, and the volume of solvent
was reduced. Upon addition of MeOH, an orange solid pre-
cipitated, was filtered, and was washed with MeOH and pe-
troleum ether to yield 0.071 g (0.102 mmol, 86%) of
product.
Synthesis of compound 27
Compound 27 was prepared using the same procedure as
for 26. Light yellow powder; yield: 0.514 g (1.4 mmol,
70%).
Data for 27
Mp > 250 °C dec. UV–vis (CH2Cl2): λmax (⑀) = 310 (3.52 ×
104) nm (L mol–1cm–1). IR (KBr): ν = 3430, 2926, 2855,
1660, 1609, 1553, 1434, 1260, 1180, 795, 752, 704 cm–1. 1H
NMR (400 MHz, DMSO-d6): δ: 11.00 (s, 2H, OH), 10.29 (s,
Data for 33
Mp 212–213 °C. UV–vis (CH2Cl2): λmax (⑀) = 287 (5.8 ×
104), 340 (2.8 × 104), 359 (3.2 × 104), 401 (5.2 × 104) nm
(L mol–1cm–1). IR (KBr): ν = 3424, 3029, 2952, 2926, 2861,
1616, 1507, 1457, 1366, 1297, 1250, 1183, 1032, 832,
2H, CH=O), 7.96 (t, 3JHH = 7.8 Hz, 1H, CH), 7.74 (d, 3JHH
=
3
7.7 Hz, 2H, CH), 7.70 (d, JHH = 7.8 Hz, 2H, CH) 7.18 (m,
4H, CH) ppm. 13C NMR (75.5 MHz, DMSO-d6): δ: 190.2,
160.5, 142.3, 137.9, 129.1, 128.1, 127.7, 123.1, 122.7,
120.1, 90.7, 87.9 ppm. EI-MS: m/z = 367 (M+, 100%), 339
(80%). Anal. calcd. for C23H13O4Nq0.5H2O: C, 73.40; H,
3.75; N, 3.72. Found: C, 73.51; H, 3.75; N, 4.36.
1
696 cm–1. H NMR (300 MHz, CDCl3, 25 °C) δ: 13.21 (s,
2H, OH), 8.86 (s, 2H, CH=N), 8.50 (s, 2H, aromatic CH),
8.16 (s, 2H, aromatic CH), 8.01 (s, 2H, aromatic CH), 7.36
(d, 4H, aromatic CH), 6.96 (d, 4H, aromatic CH), 3.85 (s,
6H, OCH3), 2.81 (m, 4H, CH2), 1.73 (m, 4H, hexyl chain),
1.48 (m, 4H, hexyl chain), 1.36 (m, 8H, hexyl chain), 0.92
(t, 6H, hexyl CH3) ppm. 13C NMR (75.5 MHz, CDCl3,
25 °C) δ: 160.1, 159.3, 158.9, 141.5, 140.0, 132.9, 127.8,
126.8, 123.7, 122.9, 122.7, 120.9, 114.9, 110.9, 55.8, 33.5,
32.1, 31.9, 29.9, 23.0, 14.4 ppm. EI-MS: m/z = 694 (M+).
Anal. calcd. for C46H50N2O4: C, 79.51; H, 7.25; N, 4.03.
Found: C, 79.74; H, 7.41; N, 4.19.
Attempted synthesis of macrocycle 29
Equimolar amounts of compound 9 and 1,2-diamino-4,5-
dialkoxybenzenes 28 were combined in a Schlenk flask. De-
gassed CHCl3 was added, and the resulting solution was
heated to reflux for 24 h. After cooling, any precipitate was
filtered, or MeCN was added until precipitate formed. The
products are unstable to chromatographic separation on sil-
ica or alumina.
Synthesis of compound 34
Compound 21 (0.062 g, 0.128 mmol) and N-(tert-
n
Data for the insoluble product obtained when R = C6H13
(29b)
butyloxycarbonyl)-1,2-diaminobenzene
32
(0.087
g,
0.418 mmol) were combined in a flask and dissolved in
10 mL of THF. After refluxing the solution overnight, the
solvent was reduced and precipitated by MeOH. The product
IR (KBr): ν = 3051, 2952, 2928, 2857, 1636, 1611, 1506,
1465, 1370, 1256, 1190, 1165, 1120, 1017, 959 cm–1.
© 2007 NRC Canada

Boden et al.
55
was recrystallized in DCM and hexanes. Filtration of the
yellow solid yielded 0.091 g (0.105 mmol, 83%) of product.
Data for 36
Mp > 300 °C. UV–vis (THF): λmax = 352 nm. Fluores-
cence (THF): λex = 370 nm, Φ = 4.9%. IR (KBr): ν = 3430,
2926, 2855, 2130, 1609, 1506, 1446, 1260, 1180, 799, 752,
704 cm–1. 1H NMR (300 MHz, CDCl3) δ: 13.31 (s, 4H, OH),
Data for 34
Mp 223–226 °C. UV–vis (CH2Cl2): λmax (⑀) = 263 (5.2 ×
104), 289 (5.5 × 104), 410 (3.8 × 104) nm (L mol–1cm–1). IR
(KBr): ν = 3436, 2955, 2925, 1736, 1639, 1609, 1595, 1510,
1447, 1366, 1216, 1159, 1048, 898, 751 cm–1. 1H NMR
(400 MHz, CDCl3, 25 °C) δ: 12.22 (s, 2H, OH), 8.90 (s, 2H,
N=CH), 8.63 (s, 2H, aromatic CH), 8.21 (s, 2H, aromatic
CH), 8.20 (d, 2H, NH), 8.12 (s, 2H, aromatic CH), 7.31 (m,
2H, aromatic CH), 7.17–7.07 (m, 6H, aromatic CH), 2.82
(m, 4H, CH2), 1.73 (m, 4H, hexyl chain), 1.53 (s, 18H, t-
butyl H), 1.48 (m, 4H, hexyl chain), 1.36 (m, 8H, hexyl
chain), 0.90 (t, 6H, hexyl CH3) ppm. 13C NMR (100.7 MHz,
CDCl3, 25 °C) δ: 164.2, 158.5, 152.8, 140.4, 138.1, 133.4,
132.9, 128.8, 128.5, 126.7, 124.2, 123.5, 123.0, 120.9,
119.6, 118.6, 111.2, 81.2, 33.4, 32.0, 31.9, 29.8, 28.6, 22.9,
14.4 ppm. ESI-MS: m/z = 865 (M+). Anal. calcd. for
C54H64N4O6 · 2 H2O: C, 71.97; H, 7.61; N, 6.22. Found: C,
71.88; H, 7.29; N, 6.40.
3
8.62 (s, 4H, CH=N), 7.65 (t, JHH = 8.3 Hz, 2H, CH), 7.47
(d, 3JHH = 7.83 Hz, 4H, CH), 7.0 – 7.4 (m, 12H, CH), 6.81
3
(s, 4H, CH), 3.93 (d, JHH = 5.0 Hz, 8H, OCH2), 1.98–0.90
(m, 60H, OCH2C7H15) ppm. 13C NMR (75.5 MHz, DMSO-
d6): δ 160.9, 160.7, 149.7, 143.7, 136.4, 135.0, 131.8, 126.3,
123.0, 122.5, 121.3, 120.0, 104.5, 90.1, 89.3, 72.0, 39.6,
30.6, 29.2, 23.9, 23.1, 14.1, 11.2 ppm. MALDI-TOF-MS:
m/z = 1392 ([M + H]+, 100%), 1453 (35%), 1495 (15%).
Anal. calcd. for C90H98N6O8 q 5H2O: C, 72.95; H, 7.35; N,
5.67. Found: C, 72.22; H, 7.32; N, 6.00.
X-ray crystallography2
A crystal of 14·2DMSO was mounted on a glass fiber, and
data were collected on a Bruker X8 APEX II diffractometer
with graphite monochromated Mo Kα radiation. The data
were collected to a maximum 2θ value of 55° in a series of φ
and ω scans in 0.5° oscillations with 20 s exposures. The
crystal-to-detector distance was 36 mm. Compound 14 crys-
tallizes as a two-component twin with the two components
related by a 180° rotation about the (010) reciprocal axis.
Data were integrated for both twin components, including
both overlapped and non-overlapped reflections. In total,
25882 reflections were integrated (10175 from component
one only, 9903 from component two only, 5804 overlapped).
Data were collected and integrated using the Bruker SAINT
software packages (53). Data were corrected for absorption
effects using the multi-scan technique (54), and were cor-
rected for Lorentz and polarization effects.
Synthesis of macrocycle 35
Under a nitrogen atmosphere, compound 26 (0.366 g,
1.0 mmol) and 1,2-diethylhexyloxy-4,5-diaminobenzene 28d
(0.364 g, 1.0 mmol) were dissolved in 20 mL of degassed
CHCl3 and 10 mL of degassed MeCN. The solution was
heated to reflux (90 °C) for 24 h, giving a clear, red solution.
Upon cooling and adding MeCN, a red powder precipitated,
which was isolated on a Büchner funnel and washed with
MeCN. Yield: 1.22 g (0.88 mmol, 88%).
The structure was solved by direct methods using non-
overlapped data from the major twin component (55). Subse-
quent refinements were carried out using an HKLF 5 format
data set containing complete data from both twin compo-
nents. The material crystallizes with two molecules of
DMSO in the asymmetric unit. All non-hydrogen atoms
were refined anisotropically, and all hydrogen atoms were
included in calculated positions but were not refined. The
batch scale refinement showed a roughly 3:1 ratio between
the major and minor twin components. The final cycle of
full-matrix least-squares refinement (56) on F2 was based on
5845 reflections from component one (including overlaps
with component two) and 278 variable parameters. The data
converged (largest parameter shift was 0.0 times its esd)
with unweighted and weighted agreement factors of R1 =
0.111 and wR2 = 0.191. The standard deviation of an obser-
vation of unit weight (57) was 0.96. The weighting scheme
was based on counting statistics. Neutral atom scattering
factors were taken from Cromer and Waber (58). Anomalous
dispersion effects were included in Fcalcd (59); the values for
Data for 35
Mp > 300 °C. UV–vis (THF): λmax (⑀) = 325 (2.53 × 104),
362 (2.23 × 104) nm (L mol–1cm–1). Fluorescence: λex
=
370 nm, Φ = 3.0%. IR (KBr): ν = 3430, 2926, 2855, 2130,
1609, 1506, 1260, 1188, 752, 704 cm–1. 1H NMR (400 MHz,
CDCl3): δ 13.34 (s, 4H, OH), 8.62 (s, 4H, CH=N), 7.75 (s,
3
2H, CH), 7.48 (d, JHH = 7.8 Hz, 4H, CH), 7.38–7.30 (m,
4H, CH), 7.26 (s, 4H, CH), 7.07 (d, 3JHH = 7.9 Hz, 4H, CH),
3
6.82 (s, 4H, CH), 3.94 (d, JHH = 5.3 Hz, 8H, OCH2), 1.85–
0.90 (m, 60H, OCH2C7H15) ppm. 13C NMR (75.5 MHz,
DMSO-d6): δ 160.9, 160.5, 149.7, 135.7, 135.0, 131.9,
131.4, 128.5, 127.2, 123.4, 122.1, 120.7, 119.5, 104.2, 90.7,
89.9, 72.0, 39.6, 30.6, 29.1, 23.9, 23.1, 14.1, 11.2 ppm.
MALDI-TOF-MS: m/z = 1390 ([M + H]+, 100%), 1445
([M + K + H2O]+, 10%). Anal. calcd. for C92H100N4O8 q
0.5H2O: C, 78.99; H, 7.28; N, 4.01. Found: C, 78.95; H,
7.22; N, 4.09.
Synthesis of macrocycle 36
′′
Macrocycle 36 was prepared using the same procedure as
for 35, starting from compound 27. Red solid; yield: 1.11 g
(0.80 mmol, 80%).
∆f′ and ∆ f were those of Creagh and McAuley (60). The
values for the mass attenuation coefficients are those of
Creagh and Hubbell (61). All refinements were performed
2 Supplementary data for this article are available on the journal Web site (canjchem.nrc.ca) or may be purchased from the Depository of Un-
published Data, Document Delivery, CISTI, National Research Council Canada, Ottawa, ON K1A 0R6, Canada. DUD 5249. For more in-
formation on obtaining material, refer to cisti-icist.nrc-cnrc.gc.ca/irm/unpub_e.shtml. CCDC 639250 contains the crystallographic data for
this manuscript. These data can be obtained, free of charge, via www.ccdc.cam.ac.uk/conts/retrieving.html (or from the Cambridge Crystal-
lographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax +44 1223 336033; or deposit@ccdc.cam.ac.uk).
© 2007 NRC Canada

56
Can. J. Chem. Vol. 86, 2008
Table 1. Crystallographic Data for 14·2DMSO.
Scheme 1. Synthesis of diformyldihydroxyphenanthrene 9.
Crystal
14·2DMSO
ν
h
Empirical formula
C20H20O8S2
Formula Mass
Color, habit
Crystal dimensions (mm)
Crystal system
452.48
MeO
OMe
MeO
OMe
Yellow, tablet
0.05 × 0.12 × 0.35
Triclinic
6
7
Space group
Z
a (Å)
b (Å)
c (Å)
α (°)
β (°)
γ (°)
Collection ranges
P-1 (no. 2)
2
1) n-BuLi
2) DMF
6.5283(14)
12.203(3)
13.460(3)
106.691(12)
99.401(12)
95.689(12)
–8 ≤ h ≤ 8;
BBr3
O
O
O
MeO
O
HO
OH
OMe
9
–15 ≤ k ≤ 15;
8
0 ≤ l ≤ 17
173(2)
1001.1(4)
1.501
Temperature
Volume (Å3)
Dcalcd (Mg m–3)
on the ring as shown in Scheme 2. We have previously re-
ported the preparation of 3,6-dimethoxyphenanthrene-9,10-
quinone 10 (45). Bromination of this compound gave 11,
along with some other by-products, which can easily be sep-
arated by chromatography. Reduction and methylation of the
quinone yielded 12, which was subsequently lithiated and
quenched with dimethylformamide to give compound 13.
Reaction of 13 with BBr3 gave, after work-up, compound
14. This compound showed the expected 1H NMR reso-
nances, but we undertook a single crystal X-ray diffraction
study to verify the correct tautomer was present. The solid-
state structure of crystals of 14 grown from DMSO is
depicted in Fig. 1, with relevant crystallographic details
summarized in Table 1. The compound exhibits a nearly pla-
nar structure, with the formyl groups directed slightly out of
the plane. In structures of salicylates, the formyl groups are
typically hydrogen-bonded to the hydroxyl groups. The
structure for 14 shows the oxygen of the aldehydes pointing
away from the alcohol and the hydroxyl moieties instead hy-
drogen-bonding with the oxygen in co-crystallized DMSO.
The extended structure shows phenanthrene molecules
stacked in a staggered arrangement, with intermolecular sep-
arations of 3.1–3.3 Å, characteristic of π–π interactions.
To incorporate alkoxy groups on phenanthrene 14, it was
necessary to protect the hydroxyl groups. Having confirmed
that the 3,6-dihydroxy tautomer was in solution, we antici-
pated that these could be readily protected. Unfortunately,
attempts to selectively protect the 3,6-dihydroxy groups of
14 failed. Upon adding base to 14, the compound undergoes
a dramatic color change to purple, and reaction with protect-
ing groups (e.g., Me2SO4) gave mixtures of products. It
seems that with deprotonation compound 14 tautomerizes
changing the reactivity of the hydroxyl groups, though we
cannot isolate this intermediate in pure form. This approach
was abandoned.
Radiation
Mo Kα (λ = 0.71073 Å)
0.313
Multi-scan
472
1.6–27.5
25882
Absorption coeff. (µ) (mm–1)
Absorption correction
F(000)
θ range for data collection (°)
Observed reflections
Independent reflections
5845 (Rint = 0.060)
Data/restraints/parameters
Maximum shift/error
Goodness-of-fit on F2
Final R indices (I > 2σ(I))
R indices (all data)
Largest diff. peak and hole (e Å–3)
5845/0/278
0.00
0.96
R1 = 0.069, wR2 = 0.171
R1 = 0.111, wR2 = 0.191
0.80 and –0.60
using the SHELXTL crystallographic software package of
Bruker-AXS (62). Additional details of the data collection
and refinement are in Table 1.
Results and discussion
Diformyldihydroxy precursors
Phenanthrene derivatives
Scheme 1 shows the sequence of reactions used to obtain
the parent diformyldihydroxyphenanthrene 9. Photocycliza-
tion of 4,4′-dimethoxystilbene
6 gave 3,6-dimethoxy-
phenanthrene 7. Dilithiation of 7 followed by quenching
with DMF gave (after work-up) compound 8 with formyl
groups in the 2,7 positions. Deprotection of the phenol
groups with BBr3 afforded target compound 9 in moderate
1
yield. H NMR spectroscopy of 9 confirms the structure of
the diol, with a single hydroxyl resonance observed at
10.96 ppm (DMSO-d6), shifted downfield due to hydrogen-
bonding with the formyl groups.
The low solubility of compound 9 is a potential limitation
to its further utility. To make soluble diformyldihydroxy-
phenanthrenes, we attempted to incorporate alkoxy groups
Triphenylene derivatives
We prepared diformyldihydroxytriphenylene 21 with pe-
ripheral hexyl groups by the route shown in Scheme 3. The
synthesis of triphenylene 18 was based on previous research
into unsymmetrically hexasubstituted triphenylenes (63, 64).
© 2007 NRC Canada

Boden et al.
57
Scheme 2. Synthesis of diformyldihydroxyphenanthrenequinone 14.
O
O
O
O
MeO
OMe
1) Na2S2O4, Bu4NBr
H2O, THF
Br2
Br
MeO
Br
Br
MeO
Br
OMe
2) Me2SO4, NaOH
MeO
OMe
OMe
10
11
12
1) n-BuLi, 0 °C
2) DMF
O
O
MeO
OMe
BBr3
O
O
O
O
HO
OH
MeO
OMe
14
13
Fig. 1. Solid-state structure of 14·2DMSO as determined by SCXRD. (a) The molecular structure, including two co-crystallized DMSO
molecules, shows the planar structure with no intramolecular hydrogen-bonding. (b, c) The extended structure of 14·2DMSO in the
solid-state reveals strong intermolecular π–π interactions. Hydrogen atoms and DMSO molecules are omitted in the extended structure
for clarity. Thermal ellipsoids are shown at 50% probability. Selected bond lengths: Aldehyde C=O: 1.202(4), 1.204(4) Å; hydroxyl
C—O: 1.325(3), 1.334(4) Å; ketone C=O: 1.193(4), 1.201(4) Å.
© 2007 NRC Canada

58
Can. J. Chem. Vol. 86, 2008
Scheme 3. Synthesis of diformyldihydroxytriphenylene 21.
C6H13 C6H13
C6H13 C6H13
MeO
B(OH)2
C6H13 C6H13
ν
I2, h , 72 h
16
Na2CO3, Pd(PPh3)4
∆
, 4 h
Br
Br
MeO
OMe
MeO
OMe
17
18
15
Br2
C6H13 C6H13
C6H13 C6H13
C6H13 C6H13
1) n-BuLi, 0/-78 °C
BBr3
2)DMF
Br
Br
O
O
O
O
HO
OH
MeO
OMe
MeO
OMe
21
20
19
Scheme 5. Synthesis of bis(salicylaldehyde)s 26 and 27.
Scheme 4. Synthesis of 4-iodophenol 23.
O
OH
OH
O
OH
O
HO
MgCl2, (CH2O)n
2
MeCN, 90 ºC
I
I
I
22
23
23
PdCl2(PPh3)2, PPh3, CuI
THF, Et3N
Y
+
In the first step, terphenyl 17 was formed by Suzuki
coupling of 1,2-dibromo-4,5-dihexylbenzene 15 and 4-
methoxyphenylboronic acid 16. Photocyclization in the pres-
ence of iodine gave triphenylene 18. Selective double
bromination of triphenylene 18 occurred at the 6,11 posi-
tions, yielding compound 19. Subsequent metal–halogen ex-
change with nBuLi, and reaction with DMF gave the
diformyldimethoxytriphenylene 20 after work-up. In the last
step, the phenol was deprotected with BBr3 to afford the
diformyldihydroxytriphenylene 21 in 20% overall yield. All
of the steps, with the exception of the photocyclization, are
fast and high-yielding. Compounds 18–21 are easily purified
through recrystallization, making 21 a convenient precursor
for macrocycle studies.
Y
HO
O
24 (Y = CH)
25 (Y = N)
26
27
(Y = CH)
(Y = N)
this reaction generally proceeds in low yield and gives a
mixture of products; the major products are 3-iodosalicyl-
aldehyde and 2-iodo-4-hydroxybenzaldehyde (65–67). We
found that using MgCl2 and paraformaldehyde (68,69) reli-
ably gave compound 23 in better (45%) yield, Scheme 4.
This compound will likely prove useful for synthesizing
other functionalized precursors to large macrocycles, such as
[3+3] macrocycles we have previously studied (37).
m-Bis(4-ethynylsalicylaldehyde)benzene and m-Bis(4-
ethynylsalicylaldehyde)pyridine
To synthesize conjugated bent bis(4-ethynylsalicy-
laldehyde) compounds, we required 4-iodosalicylaldehyde
23. This compound has been made previously by the
Reimer–Tiemann reaction starting with 3-iodophenol 22, but
© 2007 NRC Canada

Boden et al.
59
Scheme 6. Proposed syntheses of target macrocycles 29 and 30.
RO
N
OR
N
OH HO
RO
OR
9
+
H2N
NH2
OH
HO
HO
OH
28a
(R = C2H5)
N
N
28b (R = C6H13)
28c (R = C8H17
28d
)
RO
RO
N
N
OR
OR
(R = 2-EtHex)
29
RO
OR
C6H13
C6H13
N
N
C6H13
C6H13
OH
HO
21
+
28
OH
HO
HO
OH
N
N
RO
RO
N
N
OR
OR
C6H13
C6H13
30
Pd(0)-catalyzed Sonogashira–Hagihara coupling of 24
with two equiv. of 23 yielded the bis(salicylaldehyde) 26 in
75% yield, Scheme 5. Pyridine analogue 27 was prepared by
a similar procedure in 70% yield from 25. The elbow-shaped
bis(ethynylsalicylaldehyde) compounds were characterized
by NMR spectroscopy and mass spectrometry.
in an effort to obtain conjugated Schiff base macrocycles.
Reactions to form macrocycles are typically performed in
mixtures of organic solvents selected to precipitate the
macrocycle as it forms.
Phenanthrene derivatives
We expected that the reaction of 9 with diaminobenzene
derivatives would afford [3+3] Schiff base macrocycle 29,
Scheme 6. Reaction of 9 was undertaken with several differ-
ent o-phenylenediamines to control solubility. With 1,2-
Condensation studies
We investigated the condensation of the new diformyl-
dihydroxy precursors with 4,5-diamino-1,2-dialkoxybenzenes
© 2007 NRC Canada

60
Can. J. Chem. Vol. 86, 2008
Fig. 2. MALDI-TOF mass spectral evidence for the formation of macrocycle 29 (R = n-C8H17). The insets show a simulation of the
isotope distribution for the [29 + H]+ ion (bottom) and the expanded experimental data for this peak (top). The peak at m/z = 1807 is
the [29 + Na]+ ion.
dioctyloxy-4,5-diaminobenzene 28c, a solid was obtained.
The H NMR spectra of the product showed that multiple
Table 2. Conditions attempted for macrocycle 30 synthesis.
1
Solvent
R
Metal
species were formed, and it appears that the major product is
the 1:1 diol:diamine condensation species. Electrospray ion-
ization mass spectrometry (ESI-MS) showed this fragment
as the dominant species and also showed larger fragments of
the expected macrocycle. Matrix-assisted laser desorption
ionization time-of-flight (MALDI-TOF) mass spectrometry
(Fig. 2) of the solid showed the presence of macrocycle 29
as the dominant high molecular mass component, along with
traces of a larger [4+4] macrocycle. While there was evi-
dence for the formation of the desired macrocycle in this re-
action, we were unable to find conditions where the
macrocycle selectively formed in the reaction mixture, an
essential feature since the Schiff base macrocycles cannot be
separated by column chromatography.
CHCl3/MeCN
CH2Cl2/MeCN
THF
C6H13
C2H5
C2H5
C2H5
C2H5
C2H5
N/A
N/A
N/A
Toluene
N/A
EtOH
Ni(OAc)2
Zn(OAc)2
EtOH
spectrum clearly shows the incorporation of three metal cen-
ters into the macrocycle. The incorporation of three metals
into the macrocycle supports the formation of macrocycle 30
in the reaction mixture.
In an effort to selectively form macrocycle 30, and to pre-
vent possible side reactions (e.g., partial reduction of the
macrocycle), a variety of conditions was used (Table 2). In
all cases, the exact same series of resonances was repro-
Triphenylene derivatives
Condensation of 21 with o-phenylenediamines was antici-
pated to form macrocycle 30, Scheme 6. Unfortunately, the
reaction of 21 with 4,5-dialkoxy-1,2-phenylenediamines 28
in an appropriate solvent, conditions that have worked well
for other [3+3] Schiff base macrocycle reactions, afforded
1
duced in the H NMR spectrum of the isolated solid, some-
times combined with fragments of the macrocycle. ESI-MS
confirmed that fragments of the macrocycle were also pres-
ent. Metal templation, which has proved to be critical in the
synthesis of many Schiff base macrocycles, was also unsuc-
cessful to obtain the fully conjugated macrocycle. Reaction
of the diol and diamine in the presence of Ni2+ gave a black
solid, which was revealed to be a 2:1 diol to diamine frag-
ment coordinated to the metal through MALDI-TOF mass
spectrometry. The same reaction in the presence of Zn2+
gave a mixture that included the starting material.
We were frustrated and surprised that compounds 9 and
21, which appear ideal for forming [3+3] Schiff base
macrocycles, were only yielding inseparable mixtures. In our
experience, most diformyldihydroxyaromatics, such as 3,
yield the macrocycle in high yield. To understand whether or
not the reactivity of the aldehydes on 9 and 21 were unusual,
we made two model compounds by reaction of 21 with ani-
line derivatives 31 and 32, Scheme 7. Compounds 33 and 34
were obtained as microcrystalline solids in high yield. The
1H NMR spectra of these compounds show imine resonances
1
only inseparable mixtures of products. The H NMR spec-
trum of the orange solid collected from the reaction showed
several hydroxyl protons between 11.6 and 14.8 ppm. While
the largest resonance at 13.2 ppm is characteristic of a
hydroxyl group hydrogen-bonded to an imine, as in the in-
tended Schiff base macrocycle, the positions of the other
peaks are reminiscent of those observed for partially reduced
Schiff base macrocycles, where imines are reduced in situ
(this is a common problem in the formation of Schiff base
macrocycles) (70–75). MALDI-TOF mass spectrometry of
the orange product confirmed that the macrocycle was in-
deed present in the mixture. In fact, only the ring-closed
[3+3] macrocycle 30 is observed in the MALDI-TOF mass
spectrum. Further evidence for the formation of the [3+3]
Schiff base macrocycle came from a metallation experiment,
wherein the product was heated in THF in the presence of a
metal salt. A color change indicated that reaction occurred,
and, with vanadyl acetylacetonate, the MALDI-TOF mass
© 2007 NRC Canada

Boden et al.
61
Scheme 7. Synthesis of model compounds 33 and 34.
C6H13
C6H13
C6H13
C6H13
MeO
NH2
31
∆
, 4 h
O
O
MeO
N
N
OMe
HO
OH
HO
OH
21
33
C6H13
C6H13
C6H13
C6H13
NH2
NHtBOC
32
∆
, 16 h
O
O
N
N
HO
OH
HO
OH
21
NH
t-BOC
HN
t-BOC
34
at 8.86 and 8.90 ppm, respectively. There is no indication of
either reduction of the imine bond or isomerization to the
keto–enamine tautomer, which was observed previously in a
macrocycle prepared with a naphthalene diol (40). Isolation
of these model compounds supports the use of 9 and 21 to
build new multidentate Schiff base ligands.
With the goal of incorporating coordinating pyridine moi-
eties into the macrocycles, we reacted 27 with diamine 28d
1
to yield macrocycle 36 in 80% yield, Scheme 8. The H and
13C NMR data were consistent with the proposed ring struc-
ture. MALDI-TOF MS showed the expected protonated mo-
lecular ion as the major peak for macrocycle 36.
During the synthesis of macrocycles 35 and 36, we found
no evidence for formation of polymeric by-products. 1H
NMR analysis of the supernatant solution from the reaction
showed mostly more macrocycle as well as putative oligo-
mers that could not be separated. As with [3+3] Schiff base
macrocycles we have previously investigated, these conju-
gated [2+2] macrocycles can be cleanly prepared in high
yield. It was not necessary to use high dilution methods to
favor macrocycle formation, or to remove water during the
reaction to promote the condensation reaction. The
macrocycles are stabilized from hydrolysis by the formation
of strong hydrogen bonds between the imine and the phenol.
m-Bis(4-ethynylsalicylaldehyde)benzene and m-Bis(4-
ethynylsalicylaldehyde)pyridine
The geometry of compounds 26 and 27 are likely to favor
[2+2] Schiff base macrocycles. Condensation of precursor
26 with 4,5-bis(2-ethylhexyloxy)-1,2-phenylenediamine 28d
gave the diamond-shaped macrocycle 35 in 88% yield,
Scheme 8. Ethylhexyloxy substituents were required to render
the macrocyclic product soluble. In this case, the branched
substituents and the presence of a chiral center impart disor-
der to the macrocycles and ensure solubility. Macrocycles
were initially prepared using phenylenediamines substituted
with n-alkoxy chains (28a, 28b), but these macrocycles were
found to be insufficiently soluble in organic solvents to eas-
ily characterize or purify, though MALDI-TOF mass spectra
indicated that the [2+2] macrocycles were the major, if not
exclusive, products in each case.
The structure of red macrocycle 35 was verified by 1H and
13C NMR spectroscopies. Notably, the OH and imine groups
are evident as singlets at 13.34 and 8.61 ppm, respectively,
in CDCl3, consistent with average D2h symmetry for the
macrocycle. The large downfield shift of the phenol reso-
nance is characteristic of strong hydrogen-bonding to the
imine group in the macrocycle. MALDI-TOF MS of 35
(Fig. 3) showed the molecular ion expected for the
macrocycle ([35 + H]+) at m/z = 1390. The aldehyde C=O
stretch observed at 1664 cm–1 in the IR spectrum of 26 was
replaced by an intense C=N stretching mode at 1609 cm–1.
Optical properties
Our stated goal in expanding the conjugation of the
dialdehyde precursors was to develop luminescent Schiff
base macrocycles. These may be useful for chemical sensing
applications or electronic devices. Figure 4 illustrates the ab-
sorption and emission spectra of macrocycle 35 in solution,
which are similar to those of macrocycle 36. An intense
π–π* transition at 345 nm is accompanied by weaker transi-
tions that extend the absorption edge to ~500 nm. Both
macrocycles are weakly luminescent in solution, with max-
ima observed at 564 nm for both compounds, and quantum
yields of 3%–5% in THF. This is almost identical to the flu-
orescence spectrum for 37, a previously reported macrocycle
(37) (Fig. 5), indicating that conjugation is essentially local-
ized to the N,N′-bis(salicylidene)-1,2-phenylenediimine moi-
© 2007 NRC Canada

62
Can. J. Chem. Vol. 86, 2008
Scheme 8. Synthesis of conjugated diamond-shaped Schiff base
macrocycles 35 and 36.
Fig. 4. UV–vis (—) and fluorescence (---) spectra of macrocycle
35 (THF). Both spectra are normalized to unity intensity.
R O
O R
N
N
O H
H O
CHCl3 , M e C N
Y
Y
26 or 2 7
+
28d
O H
N
H O
N
(R
= 2-ethylh exyl)
R O
O R
Fig. 5. Structure of macrocycle 37.
35 (Y
36 (Y
=
=
C H )
N )
RO
OR
RO
N
N
OR
Fig. 3. MALDI-TOF MS of macrocycle 35. Inset: Experimental
(left) and simulated (right) isotope distribution patterns for the
molecular ion.
HO
OH
OH
HO
N
N
OH HO
N
N
RO
OR
37 (R = alkyl)
ethynylsalicylaldehyde)aromatic compounds (26, 27).
Studies showed that 9 and 21 do not undergo clean
cyclization reactions with o-phenylendiamines to selectively
afford [3+3] Schiff base macrocycles, but these compounds
are useful precursors for other Schiff base ligands, and per-
haps even macrocycles with the appropriate choice of
diamine. On the other hand, 26 and 27 underwent selective
condensation to form fully conjugated [2+2] Schiff base
macrocycles 35 and 36. These luminescent macrocycles with
two N2O2 binding pockets are anticipated to have interesting
coordination chemistry and aggregation behavior, which we
are studying.
ety and is unaffected by the spacer. The meta linkage of the
phenyl and pyridyl groups in 35 and 36, respectively, should
limit conjugation between the salicylaldehyde groups, and
this is observed.
Conclusions
Acknowledgement
We have developed convenient routes to the first examples
of diformyldihydroxy-functionalized phenanthrene (9, 14)
and triphenylene (21), as well as two new m-bis(4-
We thank the Natural Sciences and Engineering Research
Council of Canada (NSERC) (Discovery Grant), UBC, and
the Canadian Space Agency for funding. We are grateful to
© 2007 NRC Canada

Boden et al.
63
29. P.A. Vigato, S. Tamburini, and L. Bertolo. Coord. Chem. Rev.
251, 1311 (2007).
30. N.E. Borisova, M.D. Reshetova, and Y.A. Ustynyuk. Chem.
Joseph Hui for MALDI-TOF data, and to Brian Patrick for
solving the structure of 14.
Rev. 107, 46 (2007).
31. S. Akine, T. Taniguchi, and T. Nabeshima. Tetrahedron Lett.
49, 8861 (2001).
32. A.J. Gallant and M.J. MacLachlan. Angew. Chem., Int. Ed. 42,
5307 (2003).
33. A.J. Gallant, J.K.-H. Hui, F.E. Zahariev, Y.A. Wang, and M.J.
MacLachlan. J. Org. Chem. 70, 7936 (2005).
34. J.K.-H. Hui and M.J. MacLachlan. Chem. Commun. 2480
(2006).
References
1. H. Shimakoshi, T. Takemoto, I. Aritome, and Y. Hisaeda.
Inorg. Chem. 44, 9134 (2005).
2. J. Gawronski, K. Gawronska, J. Grajewski, M. Kwit, A.
Plutecka, and U. Rychlewska. Chem. Eur. J. 12, 1807 (2006).
3. N. Kuhnert, A.M. Lopez-Periago, and G.M. Rossignolo. Org.
Biomol. Chem. 3, 524 (2005).
4. J. Gao, R.A. Zingaro, J.H. Reibenspies, and A.E. Martell. Org.
35. T. Glaser and I. Liratzis. Synlett, 735 (2004).
36. W. Moneta, P. Baret, and J.-L. Pierre. J. Chem. Soc., Chem.
Commun. 899 (1985).
Lett. 6, 2453 (2004).
5. M. Weitzer and S. Brooker. Dalton Trans. 2448 (2005).
6. A.J. Atkins, D. Black, R.L. Finn, A. Marin-Becerra, A.J.
Blake, L. Ruiz-Ramirez, W.-S. Li, and M. Schröder. Dalton
Trans. 1730 (2003).
37. C. Ma, A. Lo, A. Abdolmaleki, and M.J. MacLachlan. Org.
Lett. 6, 3841 (2004).
38. H. Shimakoshi, H. Takemoto, I. Aritome, and Y. Hisaeda. Tet-
rahedron Lett. 43, 4809 (2002).
7. P. Arnold, A.J. Blake, C. Wilson, and J.B. Love. Inorg. Chem.
43, 8206 (2004).
39. W.T.S. Huck, F.C.J.M. van Veggel, and D.N. Reinhoudt. Recl.
8. J.M. Veauthier, E. Tomat, V.M. Lynch, J.L. Sessler, U.
Mirsaidov, and J.T. Markert. Inorg. Chem. 44, 6736 (2005).
9. S.S. Tandon, S.D. Bunge, and L.K. Thompson. Chem.
Commun. 28, 798 (2007).
10. V.V. Pavlishchuck, S.V. Kolotilov, A.W. Addison, M.J.
Prushan, R.J. Butcher, and L.K. Thompson. Chem. Commun.
468 (2002).
11. D.J. de Geest, A. Noble, B. Moubaraki, K.S. Murray, D.S.
Larsen, and S. Brooker. Dalton Trans. 467 (2007).
12. L. Salmon, P. Thuéry, E. Rivière, S. Miyamoto, T. Yamato, and
M. Ephritikhine. New J. Chem. 30, 1220 (2006).
13. J.B. Fonteche, S. Goetz, and V. McKee. Angew. Chem., Int.
Ed. 41, 4553 (2002).
14. H. Houjou, A. Iwasaki, T. Ogihara, M. Kanesoto, S. Akabori,
and K. Hiratani. New. J. Chem. 27, 886 (2003).
15. J. Wang, B. Slater, A. Alberola, H. Stoekcli-Evans, F.S.
Razavi, and M. Pilkington. Inorg. Chem. 46, 4763 (2007).
16. H. Keypour, H. Goudarziafshar, A.K. Brisdon, and R.G. Prit-
chard. Inorg. Chim. Acta 360, 2298, (2007).
Trav. Chim. Pays-Bas 114, 273 (1995).
40. A.J. Gallant, M. Yun, M. Sauer, C.S. Yeung, and M.J.
MacLachlan. Org. Lett. 7, 4827 (2005).
41. H. Meier, M. Fetten, and C. Schnorpfeil. Eur. J. Org. Chem.
779 (2001).
42. Y. Nakamura, T. Tsuihiji, T. Mita, T. Minowa, S. Tobita, H.
Shizuka, and J. Nishimura. J. Am. Chem. Soc. 118, 1006 (1996).
43. R.M. Letcher, L.R.M. Nhamo, and I.T. Gumiro. J. Chem. Soc.,
Perkin Trans. 1, 206 (1972).
44. A. Buquet, A. Couture, and A. Lablache-Combier. J. Org.
Chem. 44, 2300 (1979).
45. B.N. Boden, K.J. Jardine, A.C. W. Leung, and M.J.
MacLachlan. Org. Lett. 8, 1855 (2006).
46. M. Hanack, P. Haisch, H. Lehmann, and L.R. Subramanian.
Synthesis, 387 (1993).
47. M. Schmid, R. Eberhardt, J. Kukral, and B. Rieger. Z.
Naturforsch, 57b, 1141 (2002).
48. K.A. Bunten and A.K. Kakkar. Macromolecules, 29, 2885 (1996).
49. B.H. Dana, B.H. Robinson, and J. Simpson. J. Organomet.
Chem. 648, 251 (2002).
17. J.L. Sessler, E. Tomat, and V.M. Lynch. Chem. Commun. 4486
(2006).
50. D.-J. Kim, M.J. Choi, and S.-K. Chang. Bull. Korean Chem.
18. G. Givaja, M. Volpe, J.W. Leeland, M.A. Edwards, T.K.
Young, S.B. Darby, S.D. Reid, A.J. Blake, C. Wilson, J.
Wolowska, E.J.L. McInnes, M. Schröder, and J.B. Love.
Chem. Eur. J. 13, 3707 (2007).
Soc. 21, 145 (2000).
51. C.T. Seto, J.T. Mathias, and G.M. Whitesides. J. Am. Chem.
Soc. 115, 1321 (1993).
52. H.H. Hodgson and T.A. Jenkinson. J. Chem. Soc. 3041 (1927).
53. SAINT Version 7.03A [computer program]. Bruker AXS Inc.,
Madison, WI, USA. 1997–2003.
54. TWINABS [computer program]. Bruker Nonius scaling and
absorption for twinned crystals– V1.05, Bruker AXS Inc.,
Madison, WI, USA. 2003.
19. S. Katsiaouni, S. Dechert, C. Brückner, and F. Meyer. Chem.
Commun. 951 (2007).
20. M. Volpe, S.D. Reid, A.J. Blake, C. Wilson, and J.B. Love.
Inorg. Chim. Acta 360, 273 (2007).
21. N.H. Pilkington and R. Robson. Aust. J. Chem. 23, 2225
(1970).
22. H. Furutachi and H. Okawa. Inorg. Chem. 36, 3911 (1997).
23. H. Okawa, M. Tadokoro, Y. Aratake, M. Ohba, K. Shindo, M.
Mitsumi, M. Koikawa, M. Tomono, and D.E. Fenton. J. Chem.
Soc., Dalton Trans. 253 (1993).
24. R.R. Gagne, C.L. Spiro, T.J. Smith, C.A. Hamann, W.R. Thies,
and A.D. Shiemke. J. Am. Chem. Soc. 103, 4073 (1981).
25. W. Huang, Z. Chu, S. Gou, and T. Ogawa. Polyhedron, 26,
1483 (2007).
55. A. Altomare, M.C. Burla, M. Camalli, G.L. Cascarano, C.
Giacovazzo, A. Guagliardi, A.G.G. Moliterni, G. Polidori, and
R. Spagna. J. Appl. Cryst. 32, 115 (1999).
2
2 2
56. Least squares function minimized: Σw(Fo – Fc ) where w =
1/(σ2(Fo ) + (0.1153P)2 + 0.0000P), P = (Fo + 2Fc )/3.
2
2
2
2
57. Standard deviation of an observation of unit weight: [Σw(Fo
–
Fc )/(No – Nv)]1/2 where No = number of observations and Nv =
number of variables.
2
58. D.T. Cromer and J.T. Waber. International tables for X-ray
crystallography. Vol. IV. Kynoch Press, Birmingham, UK. Ta-
ble 2.2 A. 1974.
59. J.A. Ibers and W.C. Hamilton. Acta Crystallogr. 17, 781 (1964).
60. D.C. Creagh and W.J. McAuley. International tables for crys-
tallography. Vol. C. Edited by A.J.C. Wilson. Kluwer Aca-
26. K. Ikeda, K. Matsufuji, M. Ohba, M. Kodera, and H. Okawa.
Bull. Chem. Soc. Jpn. 77, 733 (2004).
27, B. Weber, I. Käpplinger, H. Görls, and E.-G. Jäger. Eur. J.
Inorg. Chem. 2794 (2005).
28. P.A. Vigato and S. Tamburini. Coord. Chem. Rev., 248, 1717
(2004).
© 2007 NRC Canada

64
Can. J. Chem. Vol. 86, 2008
demic Publishers, Boston, MA, USA. Table 4.2.6.8, pp. 219–
222. 1992.
68. R. Aldred, R. Johnston, D. Levin, and J. Neilan. J. Chem.
Soc., Perkin Trans. 1, 1823 (1994).
61. D.C. Creagh and J.H. Hubbell. International tables for crystal-
lography. Vol. C. Edited by A.J.C. Wilson. Kluwer Academic
Publishers, Boston, MA, USA. Table 4.2.4.3, pp. 200–206.
1992.
69. H.F. Anwar, L. Skattebøl, J. Skramstad, and T. V. Hansen. Tet-
rahedron Lett. 46, 5285 (2005).
70. A.J. Gallant, B.O. Patrick, and M.J. MacLachlan. J. Org.
Chem. 69, 8739 (2004).
62. SHELXTL Version 5.1 [computer program]. Bruker AXS Inc.,
Madision, WI, USA. 1997.
63. R.J. Bushby and C. Hardy. J. Chem. Soc., Perkin Trans. 1, 721
(1986).
71. A. Aguiari, E. Bullita, U. Casellato, P. Guerriero, S.
Tamburini, and P.A. Vigato. Inorg. Chim. Acta 202, 157
(1992).
72. K. Brychcy, K. Dräger, K.-J. Jens, M. Tilset, and U. Behrens.
64. A.N. Cammidge and H. Gopee. J. Mater. Chem. 11, 2773
(2001).
65. C. Kuroda, A. Ochi, N. Nakane, T. Umeyama, N. Muto, N.
Niimura, Y. Teramoto, H. Nogami, and G. N. Reddy. Bull.
Chem. Soc. Jpn. 73, 417 (2000).
Chem. Ber. 127, 1817 (1994).
73. D.S. Kumar and V. Alexander. Inorg. Chim. Acta 238, 63
(1995).
74. F.L. Bowden and D. Ferguson. J. Chem. Soc., Dalton Trans.
460 (1974).
66. S. Kobayashi, S. Tagawa, and S. Nakajima. Chem. Pharm.
75. Y. Tian, J. Tong, G. Frenzen, and J.-Y. Sun. J. Org. Chem. 64,
1442 (1999).
Bull. 11, 123 (1963).
67. K.A. Thakar and D.D. Goswami. J. Indian Chem. Soc. 49, 707
(1972).
© 2007 NRC Canada