Synthesis, reactivity, catenation and X-ray crystallography of Ag + and Cu+ complexes of anthraquinone-based selenoethers: A luminescent chemodosimeter for Cu2+ and Fe3+

Article abstract of DOI:10.1016/j.poly.2013.03.003

Reaction of the PhSe^- anion with 1,8-bis(2-bromoethoxy) anthracene-9,10-dione, 1,5-bis(2-bromoethoxy)anthracene-9,10-dione, 1,8-bis(2-bromoethylethyleneoxy)anthracene-9,10-dione in 1:1 ratio generates 1,8-bis(2-phenylselenoethoxy)anthracene-9,10-dione (2), 1,5-bis(2- phenylselenoethoxy)anthracene-9,10-dione (3) and 1,8-bis(2- phenylselenoethylethyleneoxy)anthracene-9,10-dione (4). The reaction of 2 with a methanolic solution of Ag(CH₃CN)₄BF₄ and Cu(CH₃CN)₄BF₄, yielded metal complexes 5 and 6, respectively. 3 formed a 1D coordination polymer (7) with Ag(CH ₃CN)₄BF₄ in a 1:2 ratio. The anthraquinone in 3 exhibits π-π interactions with distances in a range of 3.512-3.840 A?. 2 acts as a chemodosimeter for Cu²⁺ and Fe³⁺ as it undergoes an aryl ether cleavage with Cu²⁺ and Fe³⁺, and produces the luminescent 1-hydroxy-8-(2-phenylselenoethoxy)anthracene-9,10- dione (8). Intramolecular hydrogen bonding in 8 is responsible for the red-orange (λ_max 595 nm) emission. The X-ray structures of 5, 6, 7, and 8 are reported along with cyclic voltammetric analyses of new organoselenium compounds.

Full text of DOI:10.1016/j.poly.2013.03.003

Polyhedron 55 (2013) 144–154
Contents lists available at SciVerse ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Synthesis, reactivity, catenation and X-ray crystallography of Ag+ and Cu+
complexes of anthraquinone-based selenoethers: A luminescent
chemodosimeter for Cu2+ and Fe3+
⇑
Kadarkaraisamy Mariappan , Prem Nath Basa, Vinothini Balasubramanian, Sarah Fuoss, Andrew G. Sykes
Department of Chemistry, University of South Dakota, Vermillion, SD 57069, United States
a r t i c l e i n f o
a b s t r a c t
Reaction of the PhSeÀ anion with 1,8-bis(2-bromoethoxy)anthracene-9,10-dione, 1,5-bis(2-bromoeth-
oxy)anthracene-9,10-dione, 1,8-bis(2-bromoethylethyleneoxy)anthracene-9,10-dione in 1:1 ratio gener-
Article history:
Received 31 October 2012
Accepted 5 March 2013
Available online 14 March 2013
ates
1,8-bis(2-phenylselenoethoxy)anthracene-9,10-dione
(2),
1,5-bis(2-phenylselenoethoxy)
anthracene-9,10-dione (3) and 1,8-bis(2-phenylselenoethylethyleneoxy)anthracene-9,10-dione (4). The
reaction of 2 with a methanolic solution of Ag(CH3CN)4BF4 and Cu(CH3CN)4BF4, yielded metal complexes
5 and 6, respectively. 3 formed a 1D coordination polymer (7) with Ag(CH3CN)4BF4 in a 1:2 ratio. The
Keywords:
Anthraquinone
Selenoether
1D coordination polymer
Hydrogen bonding
Chemodosimeter for Cu2+ and Fe3+
anthraquinone in 3 exhibits
p–p interactions with distances in a range of 3.512–3.840 Å. 2 acts as a
chemodosimeter for Cu2+ and Fe3+ as it undergoes an aryl ether cleavage with Cu2+ and Fe3+, and produces
the luminescent 1-hydroxy-8-(2-phenylselenoethoxy)anthracene-9,10-dione (8). Intramolecular hydro-
gen bonding in 8 is responsible for the red–orange (kmax 595 nm) emission. The X-ray structures of 5,
6, 7, and 8 are reported along with cyclic voltammetric analyses of new organoselenium compounds.
Ó 2013 Elsevier Ltd. All rights reserved.
1. Introduction
compounds [10]. Anthraquinone containing compounds have also
received attention as a model for photosynthesis [11] and as
The design and synthesis of new multi and hybrid selenoethers
is an emergent field due to promising applications of organosele-
nium compounds in the field of coordination chemistry that mim-
ics biological systems [1], and as single-source precursors for type
II–VI semiconducting materials [2]. Levason has reviewed the
development of selenoethers and their complexes [3] thoroughly,
and other reviews have covered the synthesis of cyclic as well as
open multi and hybrid selenoethers [4]. Most of the earlier reports
communicated the complexation chemistry of selenoethers, and
only a few selenoethers are known in the field of molecular recog-
nition. A selena-calix[3]triazine was reported recently for guest–
host chemistry [5]. Tang’s research group reported a rhodamine
based organoselenium compound as a fluorescent probe for thiols
[6]. Zheng’s lab synthesized selenium containing calix[4]arene as
molecular tweezers receptors for ion-selective electrodes [7]. Re-
cently, Kumar et al. reported an organoselenium compound as a
selective and sensitive luminescent sensor for Hg2+, and Mahes-
wari et al. demonstrated that a tetradentate selenoether acted as
a selective ionophore towards Hg2+ ion [8]. Das and coworkers re-
ported a pincer type selenoether complex that shows notable cat-
alytic activities for Heck coupling reactions [9], and Tiekink
recently reported the therapeutic potential of organoselenium
DNA intercalators [12]. Our recent reports are based on anthraqui-
none-containing polyether compounds (open bipodands as as well
cyclic receptors) as luminescent sensors to detect oxo-acids & me-
tal ions [13], molecular switches [14] and coordination polymers of
Cu+ and Ag+ having 1,8-disubstituted anthraquinone derivatives
with N & S donor ligands [15].
Iron and copper participate in vital biological roles, and the
majority of current luminescent sensors for Cu2+, Pb2+, Zn2+, Hg2+
in solution follow PET, PCT and FRET signalling processes [16]. Also
many articles involving the fluorescent detection of heavy metal
ions have been reported [17], including OFF–ON chemodosimeter
type luminescent sensors for Fe3+ [18]. Recently Qu et al. reported
an article for the detection Fe3+ in live cell imaging [19], and Basa
et al. recently developed a chemodosimeter for Cu2+ based on
imine cleavage [20].
One report combining selenium and anthraquinone has focused
on molecular structure and not coordination and luminescence
behavior [21]. Here we integrate an anthraquinone as the lumino-
phore with short selenoether side chains at the 1,8- and 1,5-posi-
tions of anthraquinone to study the ligation and guest–host
properties with metal ions. Synthesis, ligation properties & reactiv-
ity with transition metal ions of new hybrid selenoethers including
X-ray structures with Ag+ and Cu+ metal centers are the subject of
this paper.
⇑
Corresponding author. Tel.: +1 605 677 6191; fax: +1 605 677 6397.
E-mail address: mkadarka@usd.edu (K. Mariappan).
0277-5387/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.poly.2013.03.003

K. Mariappan et al. / Polyhedron 55 (2013) 144–154
145
APEX II diffractometer using MoK radiation. Data reduction and
2. Experimental
a
refinement were completed using the WinGX suite of crystallo-
graphic software [22,23]. Structures were solved using SIR97
[24]. All hydrogen atoms were placed in ideal positions and refined
as riding atoms with relative isotropic displacement parameters.
Table 2 lists additional crystallographic and refinement informa-
tion. Both the phenyl rings connected to the selenium atoms in 6
were modeled as disordered over two positions 65:35. The fluoride
2.1. Physical measurements
1H NMR (200 MHz) and 13C NMR (50 MHz) spectra were ob-
tained in Varian 200 MHz instrument at room temperature using
deuterated solvents. Absorbance data was collected using a HP
8452A diode array spectrophotometer and Varian Cary 50 BIO.
À
atoms in BF4 in 7 were modeled as rotationally disordered over
Luminescence titrations conducted using
a SPEX fluoromax
two positions in a 50:50 ratio.
fluorimeter. Mass spectrometry was conducted using a Varian
500-MS IT ESI mass spectrometer. Cyclic voltammograms were re-
corded using a CH instruments 660 electrochemical workstation.
Elemental analyses were conducted using an Exeter CE-440
Elemental analyzer. Melting points were determined using open
capillary and uncorrected.
X-ray quality crystals of compound 5 and 7 were obtained by
diffusing diethyl ether into acetonitrile solution, and 6 by diffusing
diethyl ether into CH2Cl2:CH3OH (8:2). Crystals of 8 was obtained
by the slow evaporation of CH2Cl2:CH3OH. Crystallographic data
for 5, 6, 7, and 8 were collected at 100 K using a Bruker SMART
2.2. Chemicals and reagents
Diphenyldiselenide [25], 1,8-bis(2-bromoethoxy)anthracene-
9,10-dione [26], 1,8-bis(2-bromoethylethyleneoxy)anthraquinone
[27], 1,8-bis(2-methoxyethoxy)anthracene-9,10-dione [13b] and
1,8-bis(2-methylthioethoxy)anthracene-9,10-dione [15d] were
synthesized by prior literature results. Silver tetrafluoroborate
Ag(CH3CN)4BF4 and copper tetrafluoroborate Cu(CH3CN)4BF4 were
synthesized by available procedure [28]. Sodium borohydride,
Table 1
Electrochemical data.
Compound
Solvent
Ea (V)
1/2
Anthraquinone0/À1
AnthraquinoneÀ1/À2
Se oxidation
M1/0
1
2
3
4
5
8
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
À0.97
À1.07
À1.06
À1.08
À1.07
À0.843
À1.29
À1.41
À1.43
À1.46
À1.36
À1.29
+1.09b
+1.08b
+1.03b
+1.01b
+1.10b
+0.238b
All measurements were done at room temperature.
a
Referenced vs. Ag/AgCl, glassy carbon, 1 mM, 0.1 M TBAH.
Irreversible.
b
Table 2
Crystallographic data for compounds 5, 6, 7 and 8.
Compounds
5
6
7
8
Empirical formula
Formula weight
Wavelength
System
Temperature (K)
Crystal system
Space group
a (Å)
C
32H27NO4Se2AgBF4
C32H27NO4Se2CuBF4
797.84
C30H24O4Se2AgBF4
801.13
C22H16O4Se
423.33
842.15
Mo K 0.71073
SMART APEXII
100(2)
triclinic
Mo K 0.71073
Mo K 0.71073
Mo K 0.71073
a
a
a
a
SMART APEXII
100(2)
monoclinic
P 21/n
13.9981(12)
14.1393(12)
16.5898(14)
90.00
113.0230(10)
90.00
3022.0(4)
4
1.754
3.235
2196
SMART APEXII
100(2)
monoclinic
P 2/n
15.3479(14)
7.4932(7)
24.383(2)
90.00
93.5900(10)
90.00
2798.7(5)
2
1.924
3.388
1586
SMART APEXII
100(2)
monoclinic
P 21/n
4.9766(4)
9.8819(8)
35.631(3)
90.00
93.0470(10)
90.00
1749.8(2)
4
1.607
2.172
856
ꢀ
P1
8.1854(5)
11.5900(7
16.1173(10)
98.1190(10)
101.2220(10)
97.1370(10)
1466.52(16)
2
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dcalc (gcmÀ3
)
1.907
3.236
828
Absorption coefficient (MmÀ1
F(000)
)
h range
Index ranges
2.47–25.33
9, 13, 19
14873
5359
5056
0.394–0.445
5359/0/402
1.041
2.14–25.33
16, 16, 19
29110
5325
4237
0.2429–0.7380
5325/0/407
1.022
2.72–25.40
18, À8, 28
26090
4926
4336
0.1244–0.5615
4923/0/385
1.057
2.36–25.36
5, 11, 42
16577
3065
2598
0.584–0.706
3065/0/244
1.052
Reflections collected
Independent reflections
Observed reflections
Maximum/minimum trans.
Data/restrains/parameters
Goodness-of-fit
Final R indices[I > 2
R indices (all data)
CCDC Number
r
(I)]
0.0186
0.0201
864655
0.0454
0.0620
864656
0.0391
0.0450
864658
0.0269
0.0363
864657

146
K. Mariappan et al. / Polyhedron 55 (2013) 144–154
tetrabutylammonium hexafluorophosphate (TBAH) and all metal
perchlorate salts were purchased from Aldrich, and used without
purification. The perchlorate salts used in selectivity studies were
dried at 100 °C under vacuum over driete to minimize effects of
water of hydration. CH3CN, THF, DMF and CH2Cl2 are purchased
from Aldrich and purified using PURE SOLVTM solvent purification
system. HPLC grade anhydrous acetonitrile (Fisher/Acros) was used
in all spectroscopic studies.
2.6. Synthesis of 1,8-bis(2-phenylselenoethylethyleneoxy)anthracene-
9,10-dione (4)
Compound 4 was synthesized in an identical manner to 2, but
by using 1.19 g (2.2 mmol) of 1,8-bis-(2-bromoethylethylene-
oxy)anthracene-9,10-dione and 0.69 g (2.2 mmol) of diphenyldi-
selenide. Viscous orange liquid was obtained with 70%yield.
Elemental analyses calculated for C34H32O6Se2: C, 58.80; H, 4.64.
Found: C, 58.64; H, 4.65%. 1H NMR (at 25 °C, CDCl3): d 3.05–3.22
(t, 4H, CH2–Se); 3.81–3.92 (m, 8H, CH2–O); 4.21–4.26 (t, 4H, CH2–
O); 7.15–7.31 (m, 8H, ArH); 7.47–7.61 (m, 6H, ArH); 7.81–7.85 (d,
2H, ArH). 13C NMR (at 25 °C, CDCl3): d 26.8, 69.1, 69.7, 70.9,
119.5, 120.5, 124.7, 126.8, 128.9, 129.8, 132.5, 133.6, 134.6,
158.5, 181.9, 183.9.
Caution: Although we have experienced no difficulties with these
perchlorate salts, they should be regarded as potentially explosive
and handled with care.
2.3. Synthesis of 1,5-bis(2-bromoethoxy)anthracene-9,10-dione (1)
An identical procedure for making 1,8-bis(2-bromoeth-
oxy)anthracene-9,10-dione [26] was used to synthesize 1, by start-
ing with 2.5 g of 1,5-dihydroxyanthraquinone. A yellow fibrous
solid was obtained after silica gel column using methylene chloride
as eluent. Yield is 1.5 g, (30%) and the melting point is 195–197 °C.
Elemental Analyses calculated for C18H14O4Br2: C, 47.61; H, 3.11.
Found: C, 47.72; H, 3.20%. 1H NMR (at 25 °C, CDCl3): d 3.76–3.83
(t, 4H, CH2-Se); 4.44–4.51 (t, 4H, CH2-O); 7.26–7.31 (d, 2H, ArH);
7.67–7.75 (d, 2H, ArH); 7.94–7.98 (d, 2H, ArH). 13C NMR (at
25 °C, CDCl3): d 28.7, 69.9, 119.5, 121.1, 135.3, 137.5, 158.5,
161.2, 182.2.
2.7. Synthesis of [1,8-bis(2-phenylselenoethoxy)anthracene-9,10-
dione.Ag.CH3CN] [BF4] (5)
0.12 g (0.198 mmol) of 2 in 10 mL of CH2Cl2 was mixed with a
methanolic solution of Ag(CH3CN)4BF4 (0.078 g (0.198 mmol). The
solution was stirred for 2 h, and all the solvents were evaporated
under reduced pressure. The residue was dissolved in 10 mL of
dry acetonitrile and diethyl ether was diffused. Yellow blocks were
obtained. Yield is 0.12 g (70%) and the melting point is 248–251 °C.
Elemental analyses calculated for C32H27NO4Se2AgBF4: C, 45.64; H,
3.21; N, 1.66. Found: C, 45.78; H, 3.18; N, 1.63%. ESI MS+: 714.80
(Found); 714.31 (Calculated). 1H NMR (at 25 °C, CD3CN): d 3.65–
3.71 (t, 4H, CH2–Se); 4.44–4.49 (t, 4H, CH2–O); 7.24–7.42 (m, 8H,
ArH); 7.61–7.82 (m, 8H, ArH). 13C NMR (at 25 °C, CD3CN): d 32.8,
67.7, 120.3, 124.2, 127.2, 129.9, 130.8, 134.5, 135.7, 136.1, 158.9.
Coordinated CH3CN’s signal is merged with solvent residual peak.
2.4. Synthesis of 1,8-bis(2-phenylselenoethoxy)anthracene-9,10-dione
(2)
0.687 g (2.2 mmol) of diphenyldiselenide was mixed with
50 mL of 95% ethanol and warmed under nitrogen atmosphere. So-
dium borohydride (0.16 g in 5 mL of 1 M NaOH) was added in drop
wise till the solution become colorless. 1,8-bis(2-bromoeth-
oxy)anthracene-9,10-dione (1.00 g) made in 20 mL of THF was
added and the solution was stirred for 3 h with mild heating. The
reaction mixture was cooled to room temperature, mixed with
200 mL of distilled water and extracted with CH2Cl2. The organic
layer was dried with anhydrous Na2SO4. Most of the solvents were
evaporated under reduced pressure, and a silica gel column using
methylene chloride as eluent was used to purify the compound.
A yellow solid was obtained. Yield is 1.15 g (80%) and the melting
point is 123–125 °C. Elemental analyses calculated for C30H24O4-
Se2: C, 59.42; H, 3.99. Found: C, 59.54; H, 3.87%. 1H NMR (at
25 °C, CDCl3): d 3.34–3.41 (t, 4H, CH2–Se); 4.33–4.41 (t, 4H, CH2–
O); 7.16–7.31 (m, 8H, ArH); 7.52–7.61 (m, 6H, ArH); 7.82–7.86 (d,
2H, ArH). 13C NMR (at 25 °C, CDCl3): d 25.6, 69.4, 119.6, 120.2,
124.7, 128.9, 129.2, 133.1, 133.7, 134.8, 158.1, 182.1, 183.8.
2.8. Synthesis of [1,8-bis(2-phenylselenoethoxy)anthracene-9,10-
dione.Cu.CH3CN] [BF4] (6)
0.12 g (0.198 mmol) of 2 in 10 mL of CH2Cl2 was mixed with a
methanol solution containing 0.063 g (0.198 mmol) of Cu(CH3CN)4-
BF4. The solution was stirred for 2 h, and all the solvents were
evaporated under reduced pressure. The residue was dissolved in
10 mL of methylene chloride–methanol mixture (8:2) and diethyl
ether was diffused into the solution. Red orange blocks were ob-
tained. Yield is 0.15 g (90%) and the melting point is 155–160 °C
(dec). Elemental analyses calculated for C32H27NO4Se2CuBF4: C,
48.18; H, 3.38; N, 1.76. Found: C, 48.26; H, 3.35; N, 1.80%. ESI
MS+: 670.6 (Found); 669.98 (Calculated). 1H NMR (at 25 °C, CDCl3
with few drops of CD3OD): d 2.09 (s, 3H, CH3CN); 3.54–3.60 (t,
4H, CH2–Se); 4.40–4.46 (t, 4H, CH2–O); 7.13–7.32 (m, 8H, ArH);
7.47–7.51 (d, 4H, ArH); 7.64–7.72(t, 2H, ArH); 7.83–7.86(d, 2H,
ArH). 13C NMR (at 25 °C, CDCl3 with few drops of CD3OD): d 1.6,
32.2, 65.9, 119.1, 119.9, 125.7, 129.0, 129.6, 133.3, 134.4, 135.4,
158.1.
2.5. Synthesis of 1,5-bis(2-phenylselenoethoxy)anthracene-9,10-dione
(3)
2.9. Synthesis of catena-[1,5-bis(2-phenylselenoethoxy)anthracene-
9,10-dione.Ag][BF4] (7)
1,5-bis(2-bromoethoxy)anthracene-9,10-dione
(1)
(0.5 g,
1.1 mmol) and 0.34 g of diphenyldiselenide were used to synthe-
size 3 using the identical procedure of making 2. Compound 3
was purified by silica gel column using CH2Cl2:CH3OH (18:2) mix-
ture as eluent. Yellow colored solid was obtained. Yield is 0.3 g
(50%) and the melting point is 140–143 °C. Elemental analyses cal-
culated for C30H24O4Se2: C, 59.42; H, 3.99. Found: C, 59.31; H,
3.92%. 1H NMR (at 25 °C, CDCl3): d 3.34–3.42 (t, 4H, CH2–Se);
4.32–4.40 (t, 4H, CH2–O); 7.11–7.16 (d, 2H, ArH); 7.26–7.30 (m,
6H, ArH); 7.56–7.66 (m, 6H, ArH); 7.86–7.90 (d, 2H, ArH). 13C
NMR (at 25 °C, CDCl3): d 25.5, 69.2, 118.1, 120.1, 127.4, 129.2,
133.2, 134.9, 158.5, 182.3.
0.02 g (0.033 mmol) of 3 in 10 mL of CH2Cl2 was mixed with a
methanol solution containing 0.024 g (0.066 mmol) of Ag(CH3CN)4-
BF4. The solution was stirred for 2 h, and all the solvents were
evaporated under reduced pressure. The residue was dissolved in
10 mL of dry acetonitrile and diethyl ether was diffused. A yel-
low-orange block was obtained. Yield is 0.02 g, (70%) and the melt-
ing point is 195–200 °C (dec). Elemental analyses calculated for
C
30H24O4Se2AgBF4: C, 44.45; H, 2.96. Found: C, 44.47; H, 3.01%.
1
ESI MS+ for mononuclear: 714.90 (Found); 714.31 (Calculated) H
NMR (at 25 °C, CD3CN): d 3.35–3.42 (t, 4H, CH2–Se); 4.34–4.41 (t,

K. Mariappan et al. / Polyhedron 55 (2013) 144–154
147
4H, CH2–O); 7.26–7.31 (m, 6H, ArH); 7.56–7.77 (m, 10H, ArH). The
solubility of 7 restricted the collection of 13C NMR data.
25.5, 69.4, 116.9, 118.8, 119.7, 120.5, 121.1, 124.7, 127.5, 128.9,
129.2, 132.6, 133.2, 135.6, 135.7, 135.8, 159.6, 162.4, 182.6, 188.5.
Both methods yielded 8 as predominant product even with 2 equiv-
alent of Cu(ClO4)2.6H2O or Fe(ClO4)3.H2O.
2.10. Synthesis of 1-hydroxy-8-(2-phenylselenoethoxy)anthracene-
9,10-dione (8)
3. Results and discussion
2.10.1. Method A
Synthesize of new organoselenium compounds (2, 3, 4, and 8)
are outlined in Schemes 1 and 2, and the yields are between 70%
and 90%. The metal complexes 5 and 6 are synthesized by mixing
2 with Ag(CH3CN)4BF4 and Cu(CH3CN)4BF4 respectively in a 1:1 ra-
tio. Complex 7 is synthesized by combining 3 and Ag(CH3CN)4BF4
in a 1:2 ratio. Mixing 2 with Fe3+/Cu2+ produces 8 involving the loss
of one of the seleneoether units. Compounds 1, 2, 3, 4, and 8 are
very stable under ambient conditions with good solubility in com-
mon organic solvents like methylene chloride, chloroform, and
acetone. The metal complexes 5, 6 and 7 are moderately soluble
in methylene chloride, chloroform, acetonitrile, DMF and have
good solubility in DMSO.
0.07 g (0.11 mmol) of 2 was dissolved in 5 mL of CH2Cl2, and
mixed with the acetonitrile solution containing 0.04 g (0.11 mmol)
of Fe(ClO4)3.H2O. The mixture was stirred for 2 h. All the solvents
were evaporated under reduced pressure. The residue was dissolved
in CH2Cl2 (5 mL) resulting in an orange solution with an insoluble
pale yellow solid. Compound 8 was isolated as an orange-yellow so-
lid after performing a silica gel column with the orange CH2Cl2 solu-
tion. A very small amount of 1,8-dihydroxyanthraquinone was also
isolated. Yield is 0.042 g (90%).
2.10.2. Method B
0.1 g (0.17 mmol) of 2 was dissolved in 5 mL of CH2Cl2, and
mixed with a solution containing 0.06 g (0.17 mmol) of Cu(ClO4)2-
Á6H2O in 20 mL of CH3CN. The solution was stirred for 2 h, and all
the solvents were evaporated under reduced pressure. The residue
was dissolved in 10 mL of CH3CN and diethylether was diffused
into it. White needles of CuClO4 were obtained, and confirmed by
X-ray crystallography. The solution was purified by column chro-
matography to isolate 8 as an orange-yellow solid. A small amount
of 1,8-dihydroxyanthraquinone was also isolated. Yield is 0.05 g
(70%) and the melting point is 138–140 °C. Elemental analyses cal-
culated for C22H15O4Se: C, 62.42; H, 3.81. Found: C, 62.59; H, 3.85%.
1H NMR (at 25 °C, CDCl3): d 3.33–3.40 (t, 2H, CH2–Se); 4.35–4.42 (t,
2H, CH2–O); 7.17–7.29 (m, 5H, ArH); 7.55–7.76 (m, 5H, ArH); 7.90–
7.94 (d, 1H, ArH); 12.94 (s, 1H, OH). 13C NMR (at 25 °C, CDCl3): d
3.1. NMR Spectroscopy
1
The CH2–Se signal appears as a triplet in the H NMR spectrum
of compounds 2–8 at 3.36; 3.38; 3.08; 3.68; 3.57; 3.58; 3.33 and
3.36 ppm, respectively. The signal for CH2–Se protons in 5, 6 and
7 is deshielded up to ꢀ0.4 and ꢀ7 ppm in the 1H & 13C NMR spec-
trum, respectively, which indicates that the selenium atoms are
coordinated to the metal centers. Compound 8 displays a singlet
at 12.94 ppm which is due to the –OH group that forms an intra-
molecular hydrogen bond with the intraannular carbonyl group
(SI Fig. 7). In the 13C NMR spectrum of 8, the intraannular carbonyl
group’s signal is deshielded (ꢀ6 ppm) comparatively to 2. Aliphatic
and aromatic hydrogen ratios and elemental analyses results
Scheme 1.

148
K. Mariappan et al. / Polyhedron 55 (2013) 144–154
Scheme 2.
Fig. 1. Thermal ellipsoid diagram (50%) of [(1,8-bis(2-phenylselenoethoxy) anthraquinone)AgÁCH3CN]BF4 (5). Inset: Heart or butterfly shaped 9 member ring made by 2 and
Ag+.
support the structures of the new organoselenium compounds
shown in Schemes 1 and 2.
yielded 5 and 6, respectively. The crystal structure of 5 is shown
in Fig. 1. Selected bond lengths and bond angles are given in
Table 3. Silver (I) has a slightly distorted tetrahedral geometry in
5. The bond lengths C24–Se1 1.928(2)Å and C16–Se2 1.969(2)Å
bond length match with a previous report [29]. Ag1–Se1 and
Ag1–Se2 bond lengths are 2.5981(3)Å, 2.620(0)Å respectively,
and match one another and also with an earlier report [29]. The
3.2. Crystallography
Mixing a dichloromethane solution of 2 with a methanolic solu-
tion of Ag(CH3CN)4BF4, or Cu(CH3CN)4BF4 in equimolar ratios

K. Mariappan et al. / Polyhedron 55 (2013) 144–154
149
Table 3
[97.7(6)°] and C24–Se1–C25 [105.5(3)°] is deviated from
tetrahedral bond angle. The Se2–Cu1–O4 bite angle is 102.97(6)°,
a typical value for tetrahedral geometry, whereas, the other bite
angle Se1–Cu1–O4 (98.94(7)°) which is somewhat deviated from
the expected value. Cu–O4–C9 bond angle is 170.0(3)° which is clo-
sely linear. Copper (I) forms two nine-member, heterocyclic rings
with 2 upon coordination (Fig. 2). The crystallization solvent,
acetonitrile, occupies the fourth coordination site of Cu+ and the
Cu1–N1 bond length is 1.967(3)Å which concordant with earlier
reported [30].
Selected bond lengths (Å) and bond angles (°) of 5, 6, 7 and 8.
5
6
7
8
C24–Se1
C16–Se2
M–Se1
M–Se2
M–O4 (C@O)
C9–O4 (C@O)
C10–O3 (C@O)
M–N1
1.928(2)
1.969(2)
2.598(3)
2.620(0)
2.3901(14)
1.230
1.963(3)
1.972(3)
2.3875(5)
2.4162(6)
2.119(2)
1.220(4)
1.224(4)
1.967(3)
1.961(4)
1.971(4)
2.5456(6)
2.5511(6)
2.546 (3)
1.224 (5)
1.223 (5)
1.948(2)Å
1.241(3)
1.219 (3)
1.231
2.4366(19)
A solution of 3 in dichloromethane mixed with a methanolic
solution of [Ag(CH3CN)4]BF4 in 1:2 ratio yielded 7. The asymmetric
unit of 7 is shown in SI Fig. 1. Selected bond lengths and bond an-
gles are given in Table 3. Silver (I) has a distorted tetrahedral
geometry in 7 and it is coordinated to both selenium & both car-
bonyl oxygen. The bond lengths C24–Se1 1.961(4)Å and C16–Se2
1.971(4)Å are concordant with previous report [29]. The Ag1–Se1
and Ag1–Se2 bond lengths 2.5456(6) Å and 2.5511(6)Å are the
same [29]. The carbonyl groups bonded to the Ag+ metal center
[C9–O4 (1.224(5)Å and C10–O3 (1.223(5)Å] matches with our pre-
vious results [15d]. Ag1–O3 and Ag1–O4 are 2.528(3)Å, 2.546 (3)Å
respectively which is somewhat longer than structure 5. The C24–
Se1–C25 [94.56(18)°] and C17–Se2–C16 [97.96(18)°] are largely
deviated from regular tetrahedral bond angles. The bite angels
O3–Ag1–Se1 (85.33(6)°), O3–Ag1–Se2 [113.30(6)°] and O4–Ag1–
Se2 [90.43(6)°], O4–Ag1–Se1 [112.20(6)] are quite different from
each other. Se2–Ag1–Se1 bond angle is nearly linear
152.996(19)°, and Ag–O4–C9; Ag1–O3–C10 bond angles are
148.3(3)°, 138.8(3)° respectively and matched with earlier report
[15d].
C24–Se1–C25
C16–Se2–C17
Se1–M–Se2
Se1–M–O4 (C@O)
Se2–M–O4 (C@O)
M–O4–C9
100.08(8)
98.92(8)
134.018(9)
109.33(33)
110.41 (3)
133.49(13)
105.5(3)
97.7(6)
120.71(2)
98.94(7)
102.97(6)
170.0(3)
94.56(18)
97.96(18)
152.996(19)
112.20(6)
90.43(6)
100.96(10)
138.8(3)
Compound 7 is a one dimensional (1D) coordination polymer
and the 1D coordination polymeric network of 7 is shown in Fig. 3
after the omission of hydrogen atoms and the anions for clarity. A
p–p interaction (ranging from 3.51 to 3.84 Å) between anthraqui-
none rings in the polymeric network of 7 is observed (Fig. 4).
The central quinone ring in the anthraquinone moiety is not
coplanar in a previous anthraquinone–sulfur–silver coordination
polymer we reported [15d], but in 7, the anthraquinone rings are
virtually planar. This may be due to the involvement of both the
carbonyl groups in bonding with Ag+. The distance between two
silver nuclei (Ag–Ag, 7.493 Å) clearly indicates there is no metal–
metal interaction in the coordination polymer.
Fig. 2. Molecular structure of (50%) of [(1,8-bis(2-phenylselenoethoxy)anthraqui-
none) CuÁCH3CN]BF4 (6).
Slow evaporation of a CH2Cl2:CH3OH solution of 8 produced
suitable yellow orange needles for crystallographic studies, and
its molecular structure is shown in Fig. 5. The X-ray structure of
8 has one selenoether unit, which shows aryl ether cleavage of 2
with Fe3+. Important bond angles and bond lengths are shown in
Table 3. The phenolic hydrogen, H1 forms a hydrogen bond with
the intraannular carbonyl group. The H. . ..O bond length O(1)–
H(1)Á Á ÁO(4) equals 1.785 Å and angle is 145.93°. The bond length
C16–Se1 (1.948(2)Å) agrees with a previous report [24]. C9–O4
[1.241(3)Å] is lengthier than that of C10–O3 [1.219 (3)Å] due to
hydrogen bonding. The bond angle C16–Se1–C17 [100.96(10)°] is
as expected, and matches with earlier reports [29]. All three oxy-
gen atoms O2, O4, O1 lie in the same plane, aligned in a line,
whereas in other 1,8-anthraquinone derivatives, the anthraqui-
none ring is slightly buckled [13].
intraannular carbonyl group’s bond length [C9–O4; 1.230Å],
bonded to Ag(I) is similar in length to the outer carbonyl group
[C10–O3; 1.231Å], and the Ag–O4, 2.3901(14)Å bond length is sim-
ilar to earlier reported data [13d]. The C24–Se1–C25 [100.10(8)°]
and C16–Se2–C17 [98.93(9)°] bond angles deviated slightly from
a regular tetrahedral angle (109.5°) and agreed with an earlier
report [29]. The bite angles Se1–Ag1–O4 (109.32(3)°) and
Se2–Ag1–O4 [110.41(3)°] are a typical value for a tetrahedral
geometry, while Ag–O4–C9 bond angle is 138.48(13)°. The fourth
coordination site is occupied by acetonitrile and the Ag(I)–N1 bond
length equals 2.4366(19)Å which matches the literature [15c].
Ag(I) forms two nine-member, heterocyclic rings with 2 after
coordination (Fig. 1).
Compound 6 is isostructural with 5, and the thermal ellipsoidal
diagram is shown in Fig. 2. Copper (I) has nearly a perfect tetrahe-
dral geometry in 6. The bond lengths C24–Se1 1.963(3)Å and C16–
Se2 1.972(3)Å are matching with previous report [29]. Both Cu1–
Se1 and Cu2–Se2 bonds are 2.3875(5)Å, 2.4162(6)Å respectively
and match each other, and also with earlier reported values [29].
The intraannular carbonyl group’s bond length [C9–O4;
1.220(4)Å], bonded to Cu(I) is shorter than the external carbonyl
group [C10–O3; 1.224(4)Å], and Cu–O4 bond length 2.119(2)Å is
similar to earlier reported [24]. Bond angles C16–Se2–C17
3.3. UV–Vis absorbance studies
3 mL (1 Â 10À4 M in CH3CN) of 2 mixed with 2.0 equivalents of
Fe3+ was followed by UV–Vis spectroscopy in every 5 min for 2 h
with constant stirring. A dramatic change in the spectrum of 2
was observed with a hypochromic shift at ꢀ540 nm as shown in
Fig. 6. UV–Vis spectrum of 2 with series of metal ion is shown in
SI Fig. 2.

150
K. Mariappan et al. / Polyhedron 55 (2013) 144–154
Fig. 3. 1D coordination polymer of [(1,5-bis(2-phenylselenoethoxy)anthraquinone) Ag]BF4 (7).
A saturation point is reached after 2 h, and the absorption spec-
trum clearly shows that 2 is undergoing a chemical reaction with
Fe3+. A change in the absorption spectrum is due to a redox reac-
tion between 2 and Fe3+ which leads the formation of 8 and Fe2+
as time changes. Compound 8 has been well characterized by all
physicochemical techniques including single crystal XRD. Very
similar change in absorption spectrum of 2 is noticed when it is
mixed with Cu2+ ion also. Cu2+ yields 8 and [Cu(CH3CN)4]ClO4;
([Cu(CH3CN)4]ClO4 formation was also confirmed by X-ray crystal-
lography) with 2. Cu2+ and Fe3+ are getting reduced when they
mixed with 2, and the selenium in the broken counterpart perhaps
got oxidized. This redox reaction may have been gone through a
complex formation of 2 with Cu2+ and Fe3+. The UV–Vis spectrum
of isolated 8 in CH3CN (1 Â 10À4 M) is shown in SI Fig. 3, and sim-
ilar shape and absorbance intensities matches with the UV–Vis
spectrum of 2 with Fe3+ or Cu2+
.
Compounds 3 and 4’s UV–Vis spectrum did not change much
after mixing with Cu2+ and Fe3+ (SI Figs. 4 and 5). Only trace
amounts of cleaved products were observed after 2 days when 3
is mixed with Cu2+ and Fe3+, and no ether cleavage was observed
in 4 at all. The position of the selenoether linkage in 3 and 4 might
be the reason for the low reactivity with Cu2+ and Fe3+. There are
few reports where metal ions catalyze ether cleavage [31]. We
have studied the significance of selenium and intrannular carbonyl
Fig. 4. Top view of
better clarity.
p stacking in 7. Hydrogen atoms and anions are removed for the
Fig. 5. Molecular structure of 1-hydroxy-8-(2-phenylselenoethoxy)anthraquinone. Inset shows the linear alignment of three oxygen atoms in anthraquinone ring after
ignoring few atoms in 8.

K. Mariappan et al. / Polyhedron 55 (2013) 144–154
151
Fig. 6. Absorption spectrum of 2 (1 Â 10À4 M in CH3CN) with 2 equivalents of Cu2+ and Fe3+. Spectrum recorded at every 5 min for 2 h.
group in ether cleavage by recording the absorption changes for
acetonitrile solutions (1 Â 10À4 M) of 1,5-bis(2-phenylselenoeth-
oxy)anthracene-9,10-dione (3), 1,8-bis(2-methoxyethoxy)anthra-
cene-9,10-dione (the oxygen analog of 2) [13c], 1,8-bis
(2-methylthioethoxy)anthracene-9,10-dione (the sulfur analog of
2) [15d], 1,5-bis(2-methoxyethoxy)anthracene-9,10-dione (the
oxygen analog of 3) [32a], 1,5-bis(2-methylthioethoxy)anthra-
cene-9,10-dione (the sulfur analog of 3) [15d] and 4 with 2.0
equivalent of Cu2+ and Fe3+. No major changes in the absorption
spectrum of 3 or 4 (due to the position of selenium) or the oxygen
and sulfur analogs of 2 and 3 (due to the absence of selenium) were
observed even after 24 h indicating there is no chemical reaction,
and the results are shown in (SI Figs. 6–9). The intrannular
carbonyl group also plays a central role in cleaving aryl ether
linkage in 2, and this was confirmed by monitoring the absorbance
of 1,8-bis(2-phenylselenoethoxy)-9-anthrone-10-one [32b] mixed
with Cu2+ and Fe3+. No key changes in the absorbance (SI Fig. 10)
of 1,8-bis(2-phenylselenoethoxy)-9-anthrone-10-one indicates no
CH3CN (1 Â 10À4 M) with 2.0 equivalent of Fe3+ and without Fe3+
are shown in Fig. 7. Fluorescence intensity of 2 at 593 nm in-
creases ꢀ20-fold after adding Fe3+. The enhancement in emission
is accountable with the formation of a luminescent 1-hydroxy-8-
(2-phenylselenoethoxy)anthracene-9,10-dione (8). Emission spec-
trum of 8 in CH3CN as solvent (1 Â 10À4 M) is shown in SI Fig. 3,
and the shape and intensity match the emission spectrum of 2
with the addition of Fe3+ or Cu2+. The red–orange luminescence
in 8 is due to the intramolecular hydrogen bonding between the
phenolic hydrogen and intraannular carbonyl group [33]. The for-
mation of hydrogen bonding within 8 is confirmed by the X-ray
crystallographic analyses (Fig. 5). Very similar luminescence is
observed when 2 was mixed with Cu(ClO4)2Á6H2O. Compound 2
may be classified as a chemodosimeter for the detection of Cu2+
and Fe3+ since the chemical reaction to produce 8 is irreversible.
Apart from 8, a small amount of 1,8-dihydroxyanthraquinone
(due to double elimination) was also isolated when 2 is mixed
with Fe3+ or Cu2+.
chemical reaction with Cu2+ or Fe3+
.
Addition of other metal perchlorate solutions (no hard and soft
metal discrimination) to
2 did not produce large emission
enhancements, which means no ether cleavage was observed. 2
has a red shift after adding 2.0 equivalent of Hg2+ (SI Fig. 2), but
did not produce significant luminescence. Also adding Fe3+/Cu2+
to 3 or the oxygen/sulfur analogs of 2 or 3, or 1,8-bis(2-phenylse-
lenoethylethyleneoxy)anthracene-9,10-dione (4) did not produce
3.4. Luminescence studies
A red–orange luminescence is observed after few minutes
when 2 is mixed with aqueous or acetonitrile solutions of
Fe(ClO4)3ÁH2O. The emission spectrum (kex = 400 nm) of 2 in

152
K. Mariappan et al. / Polyhedron 55 (2013) 144–154
Fig. 7. (A) Emission spectrum of 2 (1 Â 10À4 M in CH3CN with 2 equivalent metal ions. kex = 400 nm. (B) Red–orange emission of 2 with Fe3+ and without Fe3+ under UV. (C)
Relative emission response of 2 (1 Â 10À4 M, CH3CN) at 593 nm with 2.0 equivalents of metal perchlorates.
Fig. 8. NMR spectra of 2 in presence of 1 equivalent of Fe3+
.
luminescence. Relative luminescence selectivity of 2 with different
perchlorate salts is shown in Fig. 7. 2.0 equivalents of dried per-
chlorate salt solutions were added to 2, and the emission spectrum
recorded using 400 nm as the excitation wavelength after stirring.
The emission change is most selective and sensitive for the addi-
tion of Fe3+ and Cu2+
.

K. Mariappan et al. / Polyhedron 55 (2013) 144–154
153
Fig. 9. Cyclic voltammograms of 2, 4, 5, and 8 in CH3CN using 0.1 M TBAH vs. Ag/AgCl on glassy carbon.
3.5. NMR studies of 2 with Fe3+
which we attribute to Ag(I)/Ag(0) reduction. Eo1 and Eo2 for com-
pound 8 are shifted by À0.2 and À0.12 V, respectively which may
be due to the strong intramolecular hydrogen bond. Low solubility
in CH3CN limited the electrochemical studies of 6 and 7.
NMR spectrum of 2 (1 Â 10À2 M in CDCl3) was recorded in pres-
ence of 1 equivalent of Fe3+, and observed couple of new peaks
after mixing with Fe3+. A singlet is growing progressively at
ꢀ13 ppm is due to phenolic proton in 8, and after an hour two mul-
tiplets appeared ꢀat 3.6 and 2.8 ppm. We attribute this new set of
triplets to CH2–O and CH2–Se in the broken arm from 2. NMR Spec-
tra of 2 in presence of Fe3+ with time is shown in Fig. 8.
4. Conclusion
In summary, we report the chelating mode of new selenoethers
2, 3 with Ag+ and Cu+. The ligands 2, 3 & 4, and the complexes 5, 6
and 7 have been well characterized by NMR, and X-ray crystallog-
raphy. Interestingly the intraannular carbonyl’s oxygen of 2 and 3
participate in making a coordinate covalent bond with Ag+ and Cu+
along with selenium. 3 forms a one dimensional coordination poly-
3.6. Cyclic voltammetry
Compounds 1, 2, 3, 4, 8, the silver(I) complex (5) contain the
anthraquinone moiety, and it is worth studying their redox behav-
ior by means of cyclic voltammetry.
mer (7) with Ag+, and there is a
p–p stack throughout the crystal
structure. We also describe a new fluorescence sensor based on
Se,O,Se type ligand (2) for the detection, of Cu2+ and Fe3+ involving
metal induced aryl–oxygen ether cleavage, which is irreversible. 2
is generating 8 with Cu2+ or Fe3+, and the metal ions are getting re-
duced by perhaps the oxidation of selenium in wrecked fragment.
Formation of 1-hydroxy-8-(2-phenylselenoethoxy)anthracene-
9,10-dione (8) and strong hydrogen bonding in 8 is accountable
for the fluorescence when 2 is mixing with Cu2+ and Fe3+. 3 and
4, the oxygen and sulfur analogs of 2 and 3, did not undergo aryl
ether cleavage with Cu2+ and Fe3+ within 24 h, so 2 serves as a sim-
Cyclic voltammetric measurements were carried out in 0.1 M
tetrabutylammonium hexafluorophosphate (TBAH) using CH3CN
as solvent versus Ag/AgCl as the reference electrode. The averages
of anodic and cathodic peaks were used to find Eo1 and Eo2 values of
the anthraquinone and are listed in Table 1. Cyclic voltammograms
of selected compounds (2, 4, 5, and 8) are shown in Fig. 9. Com-
pounds 1–5 and 8 show typical, first and second, one-electron,
reversible, anthraquinone reduction potentials [13c,15d] and there
is no shift in the anthraquinone’s first one-electron reduction po-
tential (Eo1) even after complexing with Ag+, but the second one-
electron reduction potential, Eo2, shifted towards positive potential
by ꢀ0.05 V. Apart from the anthraquinone’s reversible reduction
potentials, 2–5 and 8 gave an irreversible peak at ꢀ+1.0 V, which
is characteristic for the selenide to selenium oxidation which
agrees with literature [34]. 5 showed an additional irreversible
reduction potential at 0.238 V apart from the selenium oxidation,
ple chemodosimeter for Cu2+ and Fe3+
.
Acknowledgements
The authors K.M. and S.F. thank NSF-URC (CHE-0532242) for
financial support. We also thank NSF-EPSCoR (EPS-0554609) and
the South Dakota Governor’s 2010 Initiative for financial support

154
K. Mariappan et al. / Polyhedron 55 (2013) 144–154
[13] (a) V.G. Young Jr., H.L. Quiring, A.G. Sykes, J. Am. Chem. Soc. 119 (1997) 12477;
(b) B. Kampmann, Y. Lian, K.L. Klinkel, P.A. Vecchi, H.L. Quiring, C.C. Soh, A.G.
Sykes, J. Org. Chem. 67 (2002) 3878;
for the purchase of a Bruker SMART APEX II CCD diffractometer.
NSF-URC (CHE 0532242) also provided funding for the purchase
of elemental analyzer.
(c) M. Kadarkaraisamy, E. Dufek, D. Lone Elk, A.G. Sykes, Tetrahedron 61
(2005) 479;
(d) M. Kadarkaraisamy, A.G. Sykes, Inorg. Chem. 45 (2006) 779;
(e) M. Kadarkaraisamy, A.G. Sykes, Polyhedron 26 (2007) 1323.
[14] M. Kadarkaraisamy, G. Caple, A.R. Gorden, A.G. Sykes, Inorg. Chem. 47 (2008)
11644.
[15] (a) M. Kadarkaraisamy, D. Mukherjee, C.C. Soh, A.G. Sykes, Polyhedron 26
(2007) 4085;
Appendix A. Supplementary data
CCDC 864655 (5), 864656 (6), 864657 (8) and 864658 (7) con-
tains the supplementary crystallographic data. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/conts/
retrieving.html, or from the Cambridge Crystallographic Data Cen-
tre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336
033; or e-mail: deposit@ccdc.cam.ac.uk. Supplementary data asso-
ciated with this article can be found, in the online version, at
http://dx.doi.org/10.1016/j.poly.2013.03.003.
(b) D. Engelhart, M. Kadarkaraisamy, A.G. Sykes, J. Coord. Chem. 61 (2008)
3887;
(c) S.S. Peterson, T. Kirby, M. Kadarkaraisamy, R.M. Hartshorn, A.G. Sykes,
Polyhedron 28 (2009) 3031;
(d) K. Mariappan, P. Basa, Inorg. Chim. Acta 366 (2010) 344.
[16] M. Formica, V. Fusi, L. Giorgi, M. Micheloni, Coord. Chem. Rev. 256 (2012) 170.
[17] (a) X. Chen, T. Pradhan, F. Wang, J.S. Kim, J. Yoon, Chem. Rev. (2012), http://
dx.doi.org/10.1021/cr200201z;
(b) D.T. Quang, J.S. Kim, Chem. Rev. 110 (2010) 6280.
[18] D.P. Kennedy, C.M. Kormos, S.C. Burdette, J. Am. Chem. Soc. 131 (2009) 8578.
[19] X. Qu, Q. Liu, X. Ji, H. Chen, Z. Zhou, Z. Shen, Chem. Commun. 48 (2012) 4600.
[20] P.N. Basa, A.G. Sykes, J. Org. Chem. 77 (2012) 8428.
[21] W. Nakanishi, S. Hayashi, N. Itoh, Chem. Commun. (2003) 124.
[22] L.J.J. Farrugia, Appl. Crystallogr. 32 (1999) 837.
[23] G.M. Sheldrick, SHELX97 – Programs for Crystal Structure Analysis (Release
97–2), Institüt für Anorganische Chemie der Universität, Göttingen, Germany,
1998.
[24] A. Altomare, M.C. Burla, M. Camalli, G. Cascarano, C. Giacovazzo, A. Guagliardi,
A.G.G. Moliterni, G. Polidori, R. Spagna, J. Appl. Crystallogr. 32 (1998) 115.
[25] H.J. Reich, M.L. Cohen, P.S. Clark, Org. Synth. Coll. 6 (1988) 533;
59 (1979) 141.
[26] H. Kim, O.F. Schall, J. Fang, J.E. Trafton, T. Lu, J.L. Atwood, G.W. Gokel, J. Phys.
Org. Chem. 5 (1992) 482.
[27] V. Balasubramanian, Synthesis of new nitrogen-containing anthraquinone
macrocycles for the luminescence detection of heavy metal ions, M.S. Thesis,
Dissertation’s University of South Dakota, 2011.
[28] G.J. Kubas, D.F. Shriver (Eds.), Inorganic Synthesis, XIX, Plenum, NY, 1979. 90.
[29] (a) J.R. Black, N.R. Champness, W. Levason, G. Reid, Inorg. Chem. 35 (1996)
4432;
(b) J.R. Black, N.R. Champness, W. Levason, G. Reid, Inorg. Chem. 35 (1996)
1820.
[30] (a) K. Köhler, J. Eichhorn, F. Meyer, D. Vidovic, Organometallics 22 (2003)
4426;
References
[1] (a) C. Jacob, G.I. Giles, N.M. Giles, H. Sies, Angew. Chem. 115 (2003) 4890;
, Angew. Chem., Int. Ed. 42 (2003) 4742;
(b) W.-W. du Mont, G. Mugesh, C. Wismach, P.G. Jones, Angew. Chem. 113
(2001) 2547;
, Angew. Chem., Int. Ed. 40 (2001) 2486;
(c) H. Engelberg-Kulka, R. Schoulaker-Schwarz, Trends Biochem. Sci. 13 (1998)
419;
(d) G. Roelfes, D. Hilvert, Angew. Chem. 115 (2003) 2377;
, Angew. Chem., Int. Ed. 42 (2003) 2275;
(e) G.N. Schrauzer, Adv. Food Nutr. Res. 47 (2003) 73.
[2] P. O’Brien, N.L. Pickett, in: J.A. McCleverty, T.J. Meyer (Eds.), Comprehensive
Coordination Chemistry II, vol. 9, Elsevier, Oxford, 2004, p. 1005.
[3] (a) W. Levason, S.D. Orchard, G. Reid, Coord. Chem. Rev. 225 (2002) 159;
(b) W. Levason, G. Reid, W. Zhang, Dalton Trans. 40 (2011) 8491.
[4] A. Panda, Coord. Chem. Rev. 253 (2009) 1056.
[5] J. Thomas, W.V. Rossom, K.V. Hecke, L.V. Meervelt, M. Smet, W. Maes, W.
Dehaen, Chem. Commun. 48 (2012) 43.
[6] B. Tang, L. Yin, X. Wang, Z. Chen, L. Tong, K. Xu, Chem. Commun. 45 (2009)
5293.
[7] (a) X. Zeng, X. Leng, L. Chen, H. Sun, F. Xu, Q. Li, X. He, Z.Z. Zhang, J. Chem. Soc.,
Perkin Trans. 2 (2002) 796;
(b) T.M. Cormick, W.L. Jia, S.W. Wang, Inorg. Chem. 45 (2006) 147.
[31] (a) R. Cacciapaglia, L. Mandolini, F.S. Romolo, J. Phys. Org. Chem. 5 (1992) 457;
(b) S. Jia, B.J. Cox, X. Guo, Z.C. Zhang, J.G. Ekerdt, Ind. Eng. Chem. Res. 50 (2011)
849;
(b) C.Y. Liu, D.B. Qin, X.B. Leng, L.X. Chen, X.S. Zeng, F.B. Xu, Q.S. Li, X.W. He,
W.Q. Zhang, Z.Z. Zhang, Z.Z. Chin, J. Chem. 22 (2004) 804.
[8] (a) A. Kumar, J.D. Singh, Inorg. Chem. 51 (2012) 772;
(b) J.D. Singh, M. Maheshwari, S. Khan, R.J. Butcher, Tetrahedron Lett. 49
(2008) 117;
(c) M. Maheshwari, S. Khan, J.D. Singh, Tetrahedron Lett. 48 (2007) 4737.
[9] (a) P. Singh, A.K. Singh, Organometallics 29 (2010) 6433;
(b) D. Das, G.K. Rao, A.K. Singh, Organometallics 28 (2009) 6054.
[10] E.R. Tiekink, Dalton Trans. (2012), http://dx.doi.org/10.1039/c2dt12225a.
[11] K.A. Opperman, S.L. Mecklenburg, T.J. Meyer, Inorg. Chem. 33 (1994) 5295.
[12] (a) L.T. Ellis, D.F. Perkins, P. Turner, T.W. Hambley, Dalton Trans. (2003) 2728;
(b) E. Boseggia, M. Gatos, L. Lucatello, F. Mancin, S. Moro, M. Palumbo, C. Sissi,
P. Tecilla, U. Tonellato, G.J. Zagotto, J. Am. Chem. Soc. 126 (2004) 4543.
(c) G.M. Gruter, G.P.M. van Klink, O.S. Akkerman, F.B. Bickelhaupt,
Organometallics 12 (1993) 1180.
[32] (a) K. Mariappan, A.G. Sykes, unpublished results.;
(b) K. Mariappan, A.G. Sykes, V. Balasubramanian, unpublished results.
[33] J. Ruiz, C. Vicente, C. Haro, A. Espinosa, Inorg. Chem. 50 (50) (2011) 2151.
[34] (a) M. Bouroushian, Electrochemistry of Metal Chalcogenides, Monographs in
Electrochemistry, Springer-Verlag Berlin Heidelberg, 2010. pp. 57–75.
(Chapter 2);
(b) A. Sobkowiak, D.T. Sawyer, Inorg. Chem. 29 (1990) 1248.