Synthesis, characterization and luminescence properties of copper(I) complexes containing 2-phenyl-3-(benzylamino)-1,2-dihydroquinazolin-4(3H)-one and triphenylphosphine as ligands

Article abstract of DOI:10.1016/j.poly.2011.04.038

Some copper(I) complexes of the formula [Cu(L)(PPh₃) ₂]X (1-4) [where L = 2-phenyl-3-(benzylamino)-1,2-dihydroquinazolin- 4(3H)-one; PPh₃ = triphenylphosphine; X = Cl^-, NO ₃^-, ClO₄

Full text of DOI:10.1016/j.poly.2011.04.038

Polyhedron 30 (2011) 1871–1875
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Synthesis, characterization and luminescence properties of copper(I) complexes
containing 2-phenyl-3-(benzylamino)-1,2-dihydroquinazolin-4(3H)-one and
triphenylphosphine as ligands
a
a
b
S.S. Chavan a, , G.A. Gaikwad , V.A. Sawant , G.K. Lahiri
⇑
a Department of Chemistry, Shivaji University, Kolhapur, MS 416004, India
b Department of Chemistry, Indian Institute of Technology, Bombay 400076, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Some copper(I) complexes of the formula [Cu(L)(PPh3)2]X (1–4) [where L = 2-phenyl-3-(benzylamino)-
ꢀ
1,2-dihydroquinazolin-4(3H)-one; PPh3 = triphenylphosphine; X = Clꢀ, NO3ꢀ, ClO4 and BF4ꢀ] have been
Received 9 March 2011
Accepted 17 April 2011
Available online 3 May 2011
prepared and characterized on the basis of elemental analysis, IR, UV–Vis and 1H NMR spectral studies.
The representative complex of the series 4 has been characterized by single crystal X-ray diffraction
which reveal that in the complex the central copper(I) ion assumes the irregular distorted-tetrahedral
geometry. Cyclic voltammetry of the complexes indicate a quasireversible redox behavior corresponding
Keywords:
Copper(I) complexes
Crystal structure
Electrochemistry
Luminescence properties
to Cu(II)/Cu(I) couple. All the complexes exhibit intraligand (
yield in dichloromethane solution.
p
?
p⁄) fluorescence with high quantum
Ó 2011 Elsevier Ltd. All rights reserved.
1. Introduction
inflammatory and anti-convulsant effects [18,19]. In addition, con-
densed quinazolinones have drawn special attention due to their
flexibility, preparative accessibility, diversity, structural variability
and selectivity and sensitivity towards the coordinated metal
[20,21]. Because of the wide utility of quinazolinone derivatives
in biological and pharmaceutical activities and their ability to act
as polyfunctional ligands, many studies on their metal complexes
have been carried out [22–24].
In this paper, we report the synthesis of some copper(I) com-
plexes 1–4 derived from 2-phenyl-3-(benzylamino)-1,2-dihydro-
quinazolin-4(3H)-one and triphenylphosphine as ligands. All the
complexes are characterized by elemental analysis, spectroscopy
and compound 4 also by X-ray crystallography. The photolumines-
cence properties and electrochemical behavior of the complexes
are also discussed.
The coordination chemistry of monovalent copper(I) complexes
is currently receiving much interest mainly due to their potential
applications in organic light-emitting diodes (OLEDs) [1,2], supra-
molecular assemblies [3], chemical sensors [4], display devices
[5], photovoltaic cells [6], biological probing and oxygen sensing
[7], etc. Due to the favorable soft acid–soft base interaction, the
coordination chemistry of this closed-shell d10 metal ion is largely
based upon the coordination of the ligands such as various N, S, P
and halide donor ligands. The steric, electronic and conformational
effects imparted by the coordinated ligands play an essential role
in stabilizing the copper(I) state and modifying the physical and
chemical properties of the prepared complexes. Copper(I) com-
plexes with N, S, P potentially donor ligands have been extensively
studied due to their wide variation in structural motifs and rich
photophysical properties [8–10], however, only few complexes
with O-donor ligands are synthesized and structurally character-
ized [11,12]. Among the various ligands quinazolinone have-
received much more attention due to its diverse range of
pharmacological properties [13,14] and applications in several
areas such as electronics, anticorrosive agents, polymers, optical
materials and fluorescent tags in DNA sequencing [15–17].
Recently quinazolin-4(3H)-ones have been found to possess potent
central nervous system activities including analgesic, anti-
2. Experimental
2.1. General methods
All chemicals used were of reagent grade and used as received.
2-Phenyl-3-(benzylamino)-1,2-dihydroquinazolin-4(3H)-one (L)
was prepared as previously reported [25]. The copper(I) com-
pounds CuCl [26], Cu(PPh3)2NO3 [27], [Cu(MeCN)4]ClO4 [28] and
[Cu(MeCN)4]BF4 [29] were prepared according to the literature
procedure.
⇑
Microanalysis (C, H and N) were performed on a Thermo Finn-
egan FLASH EA-112 CHNS analyzer. Infrared spectra were recorded
Corresponding author. Tel.: +91 231 2609164; fax: +91 231 2691533.
E-mail address: sanjaycha2@rediffmail.com (S.S. Chavan).
0277-5387/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2011.04.038

1872
S.S. Chavan et al. / Polyhedron 30 (2011) 1871–1875
on Perkins Elmer FTIR spectrometer as KBr pellets in the 4000–
400 cmꢀ1 range. Electronic spectra were recorded in dichlorometh-
ane (10ꢀ4 M) on Shimadzu UV–Vis–NIR spectrophotometer. 1H
NMR spectra of the samples dissolved in CDCl3 were measured
on AMX-400 MHz instrument using TMS [(CH3)4Si] as an internal
standard of chemical shifts (ppm). Luminescence properties were
measured using a JASCO F.P.750 fluorescence spectrophotometer
equipped with quartz cuvette of 1 cm3 path length at room tem-
perature. Cyclic voltammetry measurements were performed with
Electrochemical Quartz Crystal Microbalance CHI-400. A standard
three electrode system consisting of Pt disk working electrode, Pt
wire counter electrode and Ag/AgCl reference electrode containing
aqueous 3 M KCl were used. All potentials were converted to SCE
scale.
2.2.4.1. Complex 4. Yield 88%, m.p. 172 °C; elemental analysis (C, H
and N, wt.%). Anal. Calc. for C57H45N3OP2F4BCu: C, 68.30; H, 4.73; N,
4.19. Found: C, 67.98; H, 4.56; N, 4.38%. IR (KBr) (cmꢀ1): 1611,
m
m
(C@O); 1581,
m(HC@N) 1481, 1435, 690, 517, m(PPh3); 1094,
(BF4); UV–Vis (CH2Cl2) kmax (nm): 256, 290, 350; 1H NMR (CDCl3)
(400 MHz): d 9.20 (s, HC@N), d 6.99–8.60 (m, Ar-H).
2.3. X-ray diffraction study
The single crystals of complex 4 suitable for X-ray analysis were
obtained by slow diffusion of diethyl ether into solution of complex
in dichloromethane. The intensity data were collected on a Nonius
MACH-3 four-circle diffractometer with graphite-monochroma-
tized Mo Ka radiation. The details of crystal data, data collection
and, the refinement are given in Table 1. The structure was solved
by direct method using the SHELXS 93 program and refined by using
SHELXL 97 software [30]. The non-hydrogen atoms were refined with
anisotropic thermal parameters. All of the hydrogen atoms were
geometrically fixed and refined using a riding model.
2.2. Synthesis of copper(I) complexes (1–4)
2.2.1. [Cu(L)(PPh3)2]Cl (1)
To a 10 ml acetonitrile solution of CuCl (1 mmol, 0.0989 g),
2 equivalent triphenylphosphine (2 mmol, 0.522 g) were added
and solution was stirred for 30 min. The solvent was evaporated
under vacuum at room temperature. The crystalline product of
[Cu(MeCN)2(PPh3)2]Cl obtained was added to a stirring solution
of ligand L (1 mmol, 0.327 g) in 10 ml dichloromethane and stirred
for 2 h at room temperature. The volume of the solvent was re-
duced under vacuum. The light yellow-green colored complexes
were developed by diffusion of diethyl ether into the filtrate.
3. Results and discussion
The reaction of two equivalent of trlphenylphosphine with cop-
per(I) salt followed by the addition of one equivalent of quinazoli-
none ligand L in dichloromethane solution at room temperature
afforded monomeric complexes of the type [Cu(L)(PPh3)2]X [where
L = 2-phenyl-3-(benzylamino)-1,2-dihydroquinꢀazolin-4(3H)-one;
PPh3 = triphenylphosphine; X = Clꢀ, NO3ꢀ, ClO4 and BF4ꢀ]. All the
complexes are microcrystalline solids that are soluble in common
organic solvents like dichloromethane, chloroform, acetonitrile,
methanol, ethanol, etc. The results of elemental analysis (C, H
and N) which are given in Section 2 confirm the assigned compo-
sition of the complexes.
2.2.1.1. Complex 1. Yield 88%; m.p. 182 °C; elemental analysis (C, H
and N, wt.%). Anal. Calc. for C57H45N3OP2ClCu: C, 71.99; H, 4.98; N,
4.42. Found: C, 71.64; H, 4.76; N, 4.58%. IR (KBr) (cmꢀ1): 1623,
m
(C@O); 1586, m(HC@N); 1479, 1434, 693, 519, m(PPh3); UV–Vis
(CH2Cl2) kmax (nm): 266, 286, 342; 1H NMR (CDCl3) (400 MHz): d
9.18 (s, HC@N), d 6.67–8.60 (m, Ar-H).
2.2.2. [Cu(L)(PPh3)2]NO3 (2)
Table 1
To a solution of [Cu(PPh3)2]NO3 (1 mmol, 0.327 g) in CH2Cl2
(10 ml) was added a solution of ligand L (1 mmol, 0.327 g) in
CH2Cl2 (10 ml) and stirred for 2 h at room temperature. The vol-
ume of the solvent was reduced under vacuum at room tempera-
ture. The light yellow colored complexes were developed by the
diffusion of diethyl ether in to the filtrate.
Crystal data and structure refinements details for complex [Cu(L)(PPh3)2]BF4 (4).
Empirical formula
Formula weight
T (K)
C57H45BCuF4N3OP2
1000.25
150(2)
Wavelength (Å)
Crystal system
Space group
a (Å)
b (Å)
c (Å)
0.71073
triclinic
ꢀ
P1
12.8591(5)
13.7884(10)
15.8076(7)
106.882(5)
97.097(4)
2.2.2.1. Complex 2. Yield 86%; m.p. 178 °C; elemental analysis (C, H
and N, wt.%). Anal. Calc. for C57H45N4O4P2Cu: C, 70.04; H, 4.85; N,
5.73. Found: C, 69.92; H, 4.64; N, 5.88%. IR (KBr) (cmꢀ1): 1623,
a
(°)
b (°)
m
(C@O); 1586, m(HC@N); 1479, 1434, 693, 519, m(PPh3); UV–Vis
c
(°)
109.548(5)
2450.5(2)
(CH2Cl2) kmax (nm): 276, 284, 348; 1H NMR (CDCl3) (400 MHz): d
9.20 (s, HC@N), d 6.99–8.20 (m, Ar-H).
V (Å3)
Z
2
Dcalc (mg/m3)
1.356
F(0 0 0)
1032
0.570
2.2.3. [Cu(L)(PPh3)2]ClO4 (3)
Absorption coefficient (mmꢀ1
)
The complex 3 was prepared similar to the procedure per-
formed in the preparation of 1 except that CuCl was replaced by
[Cu(MeCN)4]ClO4 (1 mmol, 0.327 g).
h Range for data collection (°)
Completeness to h = 25.00
Crystal size (mm)
Reflections collected/unique
Rint
3.35–25.00
99.8%
0.33 ꢁ 0.28 ꢁ 0.21
17 744/8615
0.0464
ꢀ15 6 h 6 15, ꢀ14 6 k 6 16,
ꢀ18 6 l 6 18
semi-empirical from equivalents
0.8896 and 0.8341
2.2.3.1. Complex 3. Yield 92%, m.p. 186 °C; elemental analysis (C, H
and N, wt.%). Anal. Calc. for C57H45N3O5P2ClCu: C, 67.45; H, 4.67; N,
4.14. Found: C, 67.25; H, 4.55; N, 4.72%. IR (KBr) (cmꢀ1): 1622,
Limiting indices
Absorption correction
Maximum and minimum
transmission
Data/restraints/parameters
Refinement method
Goodness-of-fit on F2
m
623
(C@O); 1583,
m(HC@N) 1480, 1434, 695, 517, m(PPh3); 1094,
m
(ClO4); UV–Vis (CH2Cl2) kmax (nm): 274, 294, 358; 1H NMR
8615/0/622
(CDCl3) (400 MHz): d 9.17 (s, HC@N), d 6.30–7.89 (m, Ar-H).
full-matrix least-squares on F2
0.931
2.2.4. [Cu(L)(PPh3)2]BF4 (4)
Final R indices [I > 2
R indices (all data) R1, wR2
r
(I)] R1, wR2
0.0563, 0.1366
0.0993, 0.1465
1.397 and ꢀ0.657
The complex 4 was prepared similar to the procedure per-
formed in the preparation of 1 except that CuCl was replaced by
[Cu(MeCN)4]BF4 (1 mmol, 0.314 g).
Largest difference in peak and hole
(e Aꢀ3
)

S.S. Chavan et al. / Polyhedron 30 (2011) 1871–1875
1873
3.1. Spectroscopic properties
The IR frequencies of selected groups in the spectra of com-
plexes are given in Section 2. The medium intensity band at
3283 cmꢀ1 observed in the IR spectrum of free ligand L is due to
the
m(NH) of the quinazoline ring. This band shifted to higher ener-
gies, by 11–15 cmꢀ1 in all of the complexes indicates noninvolve-
ment of the NAH in coordination. The characteristic
m(C@O)
frequency of ligand L occurs at 1660 cmꢀ1 shifted to lower fre-
quency at 1611–1623 cmꢀ1 in all complexes providing strong evi-
dence for involvement of carbonyl oxygen in complexation with
metal ion [22]. The band at 1618 cmꢀ1 in the spectrum of free li-
gand L attributed to the azomethine m(C@N) group. In the spectra
of the complexes this band shifted to lower frequency as a result of
coordination through the azomethine nitrogen atom [31]. This was
also confirmed by the appearance of new band at ꢂ530 cmꢀ1 in
complexes due to m(CuAN). The spectra of all the copper(I) com-
plexes exhibit the expected bands due to PPh3 ligand at around
1434, 742, 692, 506 cmꢀ1
. The strong band observed at
1374 cmꢀ1 as well as medium intensity band at 820 cmꢀ1 in the
spectra of the complex 2 assigned for presence of ionic nitrate in
the complex [32]. The perchlorate complex 3 shows a broad band
at 1093 cmꢀ1
(m
3) and a strong band aꢀt 622 cmꢀ1
(m4) is devoid
of any splitting suggesting that the ClO4 anion is not coordinated
to the copper atom [33]. However, a broad band obseꢀrved at
1094 cmꢀ1 in complex 4 corresponds to presence of BF4 anion
in the complex [34].
The electronic spectra of all copper(I) complexes (1–4) in
dichloromethane (10ꢀ4 M) were measured at room temperature.
In the spectra of complexes no d–d transitions are expected, the
UV–Vis band observed at 342–358 nm is assigned to ligand-origi-
nating intra-ligand transition together with some metal-ligand
charge transfer (MLCT) character [35]. The high energy bands lo-
cated in the UV region of the complexes at 256–274 and 284–
Fig. 1. Molecular structure of [Cu(L)(PPh3)2]BF4 (4).
294 nm are assigned to intraligand p–
p⁄ transitions.
Table 2
0
The 1H NMR spectral data of all copper(I) complexes (1–4) in
CDCl3 are given in Section 2. In complexes 1–4 the resonances of
phenyl protons of the coordinated PPh3 ligands overlap to some ex-
tent with those of the phenyl hydrogen atoms of ligand L. However,
the broad multiplet observed in the range d 6.30–8.60 ppm for all
the complexes were assigned to the phenyl group of PPh3 together
with ring protons of ligand L. Aside from the aromatic protons, the
imine proton appears as a singlet at about d 9.20 ppm in the spectra
of all complexes. The downfield shift of the imine proton in the
complexes relative to the free ligand L can be attributed to the desh-
ielding effect resulting from the coordination of the ligand [36].
Selected bond lengths (ÅA) and bond angles (°) for complex 4.
Cu(1)AO(1)
2.123(3)
2.123(4)
2.2460(12)
2.2476(11)
1.360(6)
1.511(7)
1.370(7)
1.482(7)
76.53(12)
101.86(8)
114.77(10)
108.41(8)
112.93(10)
127.91(5)
116.7(4)
132.1(3)
110.5(3)
111.3(5)
106.2(5)
110.7(5)
116.7(4)
132.1(3)
110.5(3)
116.9(4)
126.1(4)
116.7(4)
Cu(1)AN(1)
Cu(1)AP(2)
Cu(1)AP(1)
N(2)AC(1)
N(2)AC(8)
N(3)AC(7)
N(3)AC(8)
O(1)ACu(1)AN(1)
O(1)ACu(1)AP(2)
N(1)ACu(1)AP(2)
O(1)ACu(1)AP(1)
N(1)ACu(1)AP(1)
P(2)ACu(1)AP(1)
C(15)AN(1)AN(2)
C(15)AN(1)ACu(1)
N(2)AN(1)ACu(1)
N(3)AC(8)AC(9)
N(3)AC(8)AN(2)
C(9)AC(8)AN(2)
C(15)AN(1)AN(2)
C(15)AN(1)ACu(1)
N(2)AN(1)ACu(1)
C(1)AN(2)AN(1)
C(1)AN(2)AC(8)
N(1)A N(2)AC(8)
3.2. Crystal structure
The crystals of [Cu(L)(PPh3)2]BF4 (4) were grown by slow diffu-
sion of diethyl ether into a solution of complex in dichloromethane
and structure was determined by X-ray crystallography. X-ray
analysis revealed that the complex 4 crystallizes in the triclinic
ꢀ
space group P1. The crystal of complex 4 contains discrete cation
[Cu(L)(PPh3)2]+ and tetrafluoroborate counter anion. The molecular
structure of 4 along with the atom numbering scheme is illustrated
in Fig. 1 and selected bond lengths and bond angles are collected in
Table 2.
The complex is mononuclear and central copper(I) ion exhibit
highly distorted tetrahedral geometry with CuNOP2 coordination.
The quinazoline ligand is chelated to the copper ion in neutral
bidentate form through azomethine nitrogen and carbonyl oxygen
forming a five-membered chelation ring. The distorted four-coor-
dinate geometry of copper(I) is completed by two triphenylphos-
phine ligands. The largest deviation from the ideal tetrahedral
geometry is reflected by the restricted bite angles of the chelating
ligands. The intraligand O(1)ACu(1)AN(1) chelate angle,
76.53(12)° is much less than 109.4°. However, the
P(2)ACu(1)AP(1), 127.91(5)° angle have opened up due to the ste-
ric effects from the bulky PPh3 ligands. The average CuAN and
0
CuAP bond distances are 2.123 and 2.246 ÅA, respectively, and are

1874
S.S. Chavan et al. / Polyhedron 30 (2011) 1871–1875
Table 4
compa0rable to those reported for [Cu(A)(PPh3)2]ClO4 (2.098 and
2.251 ÅA) [37].
Electrochemical data for copper(I) complexes.
Torsion angles in the chelating ring and quinazoline group are
listed in Table 3. The chelating ring Cu(1)AN(1)AN(2)AC(1)AO(1)
is nearly planar with sum of three N atom bond angles is 359.3°.
However, some strain in the chelate ring is suggested by the devi-
ation from the 120° angle about the N atom Cu(1)AN(1)AC(15),
132.1(3)°; Cu(1)AN(1)AN(2), 110.5(3)° and C(15)AN(1)AN(2),
116.7(4)°.
Compound
Epa (V)
Epc (V)
D
Ep (mV)
E1/2 (V)
1
2
3
4
0.706
0.673
0.694
0.720
0.557
0.542
0.576
0.558
149
131
118
162
0.631
0.608
0.635
0.639
Supporting electrolyte: n-Bu4NClO4 (0.05 M); complex: 0.001 M; solvent: DMF;
Ep = Epa ꢀ Epc where, Epa and Epc are anodic and cathodic potentials, respectively;
E1/2 = ½ (Epa + Epc); scan rate: 50 mV sꢀ1
D
.
In the heteroatomic part of quinazoline, the angles
N(3)AC(8)AC(9), 111.3(5); N(3)AC(8)AN(2), 106.2(5) and
C(9)AC(8)AN(2), 110.7(5); indicate the sp3 hybridized state of
the carbon atom, and the geometry around C(8) can be viewed in
terms of a distorted tetrahedral geometry. The two NAC (sp2) bond
distances [N(2)AC(1), 1.360(6) and N(3)AC(7), 1.370(7)] show
double bond character and two NAC (sp3) bond distances
[N(2)AC(8), 1.511(7) and N(3)AC(8), 1.482(7)] show single bond
character. The sum of the angles around N(2) and N(3) are 359.7°
and 360.0°, respectively. The benzaldehyde moiety directly linked
at C(8) is oriented at an angle of 83.7(7)° with respect to the qui-
nazoline ring. The quinazoline ring and the benzaldehyde moiety
linked through N(1) and C(15) are trans to each other, thus show-
ing
E-configuration.
Further,
the
tortional
angle
of
N(2)AN(1)AC(15)AC(16) is 175.2(3)° indicating an anti-periplanar
arrangement.
3.3. Electrochemistry
The electrochemical properties of the copper(I) complexes have
been examined cyclic voltammetrically in 10ꢀ3 M CH2Cl2 solution
containing 0.05 M n-Bu4NClO4 as supporting electrolyte and redox
potentials are expressed with reference to Ag/AgCl. All the mea-
surements were carried out in the potential range +1.5–ꢀ1.5 V
with scan rate 50 mV sꢀ1. The results were collected in Table 4.
The electrochemical potentials of the copper(I) complexes were
characterized by well-defined redox process in positive potential
side. Since the ligand used in this work is not reversibly oxidized
or reduced in the applied potential range, the redox processes
are assigned to the metal centers only. For all the copper(I) com-
plexes the reduction wave (Epc, 0.673–0.720 V) corresponding to
reduction of Cu(II) to Cu(I) is obtained. During the reverse scan
Fig. 2. Normalized emission spectra of the copper(I) complexes (1–4).
Table 5
Fluorescence spectral data of L and its copper(I) complexes.
Complex
Excitation (nm)
Emission (nm)
U
L
1
2
3
4
303
386
386
392
389
413
434
420
499
504
0.004
0.086
0.082
0.084
0.091
the oxidation of Cu(I) to Cu(II) occurs in the potential range (Epa
0.542–0.576 V). The quasireversible character is accounted from
the values of the limiting peak-to-peak separation ( Ep) ranging
,
D
from 118 to 162 mV under the conditions of measurements.
However, all the copper(I) complexes gives strong fluorescence
with high quantum yield in dichloromethane solution. The
copper(I) complexes 1–4 show blue to bluish-green emission band
with a maximum wavelength at 420–504 nm upon excitation at
386–392 nm. The fluorescence emission observed in the com-
3.4. Fluorescence spectral studies
The photoluminescence properties of the ligand L and its cop-
per(I) complexes (1–4) were studied at room temperature in
dichloromethane solution. The emission spectra of copper(I) com-
plexes are depicted in Fig. 2 and data are collected in Table 5. The
ligand L exhibit very weak fluorescence signal centered at 413 nm
with an excitation maxima at 303 nm. The emission observed in
plexes is assigned to intra-ligand (p ?
p⁄) transition [38]. The
red shift in fluorescence emission of the complexes in comparison
to that of the free ligand L can be attributed to the coordination of
ligand to the copper(I) ions which effectively increases the rigidity
of the ligands and reduces the loss of energy via radiation less ther-
mal vibrational decay [39]. Further, the presences of counter an-
ions show a pronounced effect on the emission energy of the
complexes (Fig. 2). The emission energy decreases in the following
sequence: 2 (NO3ꢀ) > 1 (Clꢀ) > 3 (ClO4ꢀ) > 4 (BF4ꢀ).
the ligand
L can be assigned to p ?
p⁄ electron transition.
Table 3
Torsion angles for chelating ring and quinazolinone group.
Cu(1)AN(1)AN(2)AC(1)
Cu(1)AO(1)AC(1)AN(2)
N(1)AN(2)AC(1)AO(1)
O(1)ACu(1)AN(1)AN(2)
N(1)ACu(1)AO(1)AC(1)
N(3)AC(8)AC(9)AC(10)
N(2)AN(1)AC(15)AC(16)
ꢀ4.8(4)
The fluorescence quantum yield (U) of the complexes was
8.8(5)
ꢀ2.6(6)
6.6(2)
determined by using the quinine sulfate as a reference with known
UR of 0.52 and appeared at 0.080–0.091. The area of emission spec-
trum was integrated using the software available in the instrument
and quantum yield was calculated according to the following
equation.
ꢀ8.4(3)
83.7(7)
175.2(3)

S.S. Chavan et al. / Polyhedron 30 (2011) 1871–1875
1875
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Appendix A. Supplementary data
CCDC 784048 contains the supplementary crystallographic data
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