Copper(I) complexes with Schiff base and 1,2-bis(diphenylphosphino)ethane as ligands: Synthesis, structure and catalytic properties for the amination of aryl halide

Article abstract of DOI:10.1016/j.ica.2010.06.023

Some copper(I) complexes of the type [Cu(L)(dppe)]X (1-4) [where L = (3-trifluoromethylphenyl)pyridine-2-ylmethylene-amine; dppe = 1,2-bis(diphenylphosphino)ethane; X = Cl^-, CN^-, ClO ₄^- and BF₄^-] have been synthesized by the condensation of 3-aminobenzotrifluoride with 2-pyridinecarboxaldehyde followed by the reaction with CuCl, CuCN, [Cu(MeCN)₄]ClO₄ and [Cu(MeCN)₄]BF₄ in presence of dppe. The complexes 1-4 were then 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 complex the central copper(I) ion assumes the irregular pseudo-tetrahedral geometry. The catalytic activity of the complexes was tested and it was found that all the complexes worked as effective catalyst in the amination of aryl halide.

Full text of DOI:10.1016/j.ica.2010.06.023

Inorganica Chimica Acta 363 (2010) 3359–3364
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Inorganica Chimica Acta
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Copper(I) complexes with Schiff base and 1,2-bis(diphenylphosphino)ethane
as ligands: Synthesis, structure and catalytic properties for the amination
of aryl halide
a
a
b
S.S. Chavan a, , S.K. Sawant , V.A. Sawant , G.K. Lahiri
*
a Department of Chemistry, Shivaji University, Kolhapur 416004, MS, 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 type [Cu(L)(dppe)]X (1–4) [where L = (3-trifluoromethylꢀphenyl)pyri-
ꢀ
dine-2-ylmethylene-amine; dppe = 1,2-bis(diphenylphosphino)ethane; X = Clꢀ, CNꢀ, ClO4 and BF4
]
Received 22 January 2010
Received in revised form 11 June 2010
Accepted 14 June 2010
have been synthesized by the condensation of 3-aminobenzotrifluoride with 2-pyridinecarboxaldehyde
followed by the reaction with CuCl, CuCN, [Cu(MeCN)4]ClO4 and [Cu(MeCN)4]BF4 in presence of dppe.
The complexes 1–4 were then 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 complex the central copper(I) ion assumes the irregular pseudo-tet-
rahedral geometry. The catalytic activity of the complexes was tested and it was found that all the com-
plexes worked as effective catalyst in the amination of aryl halide.
Available online 22 June 2010
Keywords:
Schiff base
Copper(I) complexes
Single crystal X-ray diffraction
Amination of aryl halides
Ó 2010 Elsevier B.V. All rights reserved.
1. Introduction
nanthroline [14] and other nitrogen, oxygen containing ligands
[15,16] together with copper(I) reagents have been applied for
The catalytic amination of aryl halide by transition metal ion is
subject of growing interest in past few decades. This method in-
volves production of arylamines by coupling of aryl halide with
amines in presence of stoichiometric amount of transition metal
ion. Arylamines are prevalent in organic compounds, shows wide
utility in fine chemicals, dyes and polymers [1]. These are impor-
tant components in many biological active natural products,
medicinally important compounds as well as in materials with
useful electrical and mechanical properties [2–4]. High purity tria-
rylamines find applications in xerographic photoreceptors as con-
stituents of non linear optical chromophores useful in design of
integrated electro-optic switches and modulators [5]. This wide
spread importance of arylamines has led to the development of
many synthetic methodologies for the production of arylamines.
Amongst them, the classical copper mediated Ullman coupling
and the recently developed Pd(0) catalyzed aryl coupling are more
commonly used methods [6–9]. Although the Pd-catalyzed amina-
tion of aryl halide has recently become the most important method
for laboratory scale synthesis of arylamines; the copper mediated
coupling is still the reaction of choice due to its cheap price and
environmentally friendly nature. Many ligand systems such as
amino acid [10], diamines [11], di-imines [12], diols [13], 1,10-phe-
the production of arylamine under mild condition. More recently
Cu(PPh3)3Br [17] and Cu(phen)2Cl [18] have also been reported
for the amination of aryl halides.
In this paper we report synthesis of some copper(I) complexes
1–4 by the reaction of Schiff base ligand (3-trifluoromethyl-
phenyl)-pyridine-2-ylmethylene-amine (L) with CuCl, CuCN,
[Cu(MeCN)4]ClO4 and [Cu(MeCN)4]BF4 in presence of 1,2-
bis(diphenylphosphino)ethane as a coligand. All the complexes
were characterized on the basis of elemental analysis, IR, UV–Vis,
1H NMR spectral studies and compound 4 also by X-ray crystallog-
raphy. The catalytic performance of all the copper(I) complexes in
the amination of aryl halide has also been discussed.
2. Experimental
2.1. Materials and methods
The reagents used in synthesis of copper(I) complexes were 2-
pyridinecarboxaldehyde (Alfa Aesar), 3-aminobenzotrifluoride
(Alfa Aesar), 1,2-bis(diphenylphosphino)ethane (Aldrich, USA)
were of reagent grade used without further purification. The Schiff
base ligand (3-trifluoromethylphenyl)-pyridine-2-ylmethylene-
amine (L) was prepared as previously reported [19]. Other reagents
included bromobenzene, iodobenzene, aniline, p-bromoaniline,
p-anisidine and KOt–Bu. The copper(I) compounds CuCl [20],
* Corresponding author. Tel.: +91 231 2609164; fax: +91 231 2691533.
E-mail address: sanjaycha2@rediffmail.com (S.S. Chavan).
0020-1693/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2010.06.023

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S.S. Chavan et al. / Inorganica Chimica Acta 363 (2010) 3359–3364
[Cu(MeCN)4]ClO4 [21] and [Cu(MeCN)4]BF4 [21] were prepared
according to the literature procedure. Elemental analysis (C, H
and N) of the copper(I) complexes were conducted on Thermo
Finnigan FLASH EA-1112 CHNS analyzer. IR spectra were recorded
on a Perkin–Elmer-100 FTIR spectrometer. 1H NMR spectra of the
samples dissolved in CDCl3 were measured on a AMX 400 MHz
instrument using TMS[(CH3)4Si] as an internal standard of chemi-
cal shifts (ppm). Electronic spectra were recorded in dichlorometh-
ane (10ꢀ4 M) on Shimadzu 3600 UV–Vis-NIR spectrophotometer.
Mass spectra were measured on GCMS Shimadzu-2010.
(9.4), 397 (1.4); 1H NMR (CDCl3) (400 MHz) d 9.49 (s, HC@N),
7.22–8.78 (m, Ar-H), d 2.67 (s, PCH2CH2P).
2.2.4. Preparation of [Cu(L)(dppe)]BF4 (4)
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).
Complex 4: Yield 84%, m.p. 174 °C; elemental analysis (C, H and
N, wt.%) Anal. Calc. for C39H33 BCuF7N2P2: C, 58.63; H, 4.16; N, 3.51.
Found: C, 58.62; H, 4.47; N, 3.54%. IR (KBr) (cmꢀ1) 1587,
t(HC@N);
1483, 1435, 1168, 693, t(dppe); 1071, t(BF4); UV–Vis (CH2Cl2) kmax
(nm)(
e
ꢁ 103, Mꢀ1 cmꢀ1): 288 (13.0), 300 (9.4), 392 (1.3); 1H NMR
2.2. Synthesis
(CDCl3) (400 MHz): d 9.49 (s, HC@N), d 7.20–8.67 (m, Ar-H), d 2.67
(s, PCH2CH2P).
2.2.1. Preparation of [Cu(L)(dppe)]Cl (1)
To a solution of Schiff base ligand L (1 mmol, 0.250 g) was
added a solution of 1,2-bis(diphenylphosphino)ethane (1 mmol,
0.397 g) and CuCl (1 mmol, 0.0989 g) in 10 ml dichloromethane.
The reaction mixture was stirred under nitrogen atmosphere at
room temperature for 2 h and then the solution was evaporated
to small volume under vacuum. The pale yellow coloured complex
was developed by diffusion of diethyl ether into the solution.
Complex 1: Yield 85%; m.p. 130 °C; elemental analysis (C, H and
N, wt.%) Anal. Calc. for C39H33ClCuF3N2P2: C, 62.65; H, 4.45; N, 3.75.
2.3. Catalytic activity for the amination of aryl halide
The amination of bromobenzene and iodobenzene catalyzed by
copper(I) complexes was carried out according to the procedure
(Scheme 1): 0.05 mmol of copper(I) catalyst was added to 4 mmol
of respective arylamine, 8 mmol of bromobenzene or iodobenzene,
12 mmol of KOt–Bu in toluene and the reaction mixture was stir-
red for 12 h at 90 °C under nitrogen. The reaction mixture was then
cooled to room temperature and the solution was filtered to re-
Found: C, 62.75; H, 4.47; N, 3.78%. IR (KBr) (cmꢀ1): 1590,
t(HC@N);
1483, 1435, 1165, 693,
t(dppe); UV–Vis (CH2Cl2) kmax
(nm)(
e
ꢁ 103, Mꢀ1 cmꢀ1): 278 (13.7), 298 (9.8), 396 (0.53); 1H
Table 1
NMR (CDCl3) (400 MHz), d 9.45 (s, HC@N), 7.18–8.75 (m, Ar-H), d
Crystal data and structure refinements details for [Cu(L)(dppe)]BF4(4).
2.67 (s, PCH2CH2P).
Empirical formula
Formula weight
Crystal system
Space group
a (Å)
C39H33BCuF7N2P2
798.96
Triclinic
2.2.2. Preparation of [Cu(L)(dppe)]CN (2)
ꢀ
P1
The complex 2 was prepared similar to the procedure per-
formed in the preparation of 1 except that CuCl was replaced by
CuCN (1 mmol, 0.0895 g).
10.3579(4)
13.2014(5)
14.5780(5)
92.805(3)
102.438(3)
111.747(4)
1789.75(11)
2
b (Å)
c (Å)
a
(°)
Complex 2: Yield 85%, m.p. 122 °C; elemental analysis (C, H and
N, wt.%) Anal. Calc. for C40H33CuF3N3P2: C, 65.08; H, 4.51; N, 5.69.
b (°)
c
(°)
Found: C, 65.25; H, 4.54; N, 5.72%. IR (KBr) (cmꢀ1): 1585,
t(HC@N);
V (A3)
1483, 1435, 1168, 693,
t(dppe); 2110,
t
(C„N); UV–Vis (CH2Cl2)
Z
Dcalc (mg mꢀ3
)
1.483
0.768
816
kmax (nm)(
e
ꢁ 103, Mꢀ1 cmꢀ1): 288 (13.7), 308 (9.7) 402 (1.2); 1H
l
(Mo K
a
)(mmꢀ1
)
NMR (CDCl3) (400 MHz): d 9.47 (s, HC@N), 7.18–8.75 (m, Ar-H), d
F (0 0 0)
2.66 (s, PCH2CH2P).
Data collection
Temperature (K)
150(2)
h Minimum–maximum (°)
Dataset [h, k, l]
Total, unique data, Rint
Observed data
3.46–25.00
2.2.3. Preparation of [Cu(L)(dppe)]ClO4 (3)
ꢀ12/12, ꢀ15/15, ꢀ17/16
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).
13146, 6271, 0.0214
I > 2r(I)
Refinement
Complex 3: Yield 89%, m.p. 171 °C; elemental analysis (C, H and
N, wt.%) Anal. Calc. for C39H33ClCuF3N2O4P2: C, 57.71; H, 4.11; N,
3.45. Found: C, 57.83; H, 4.37; N, 3.48%. IR (KBr) (cmꢀ1): 1590,
Number of reflection, number of parameters
R1, R1
wR2, wR2
16172, 1155
0.0313, 0.0392
0.0823, 0.0843
1.078
Goodness-of-fit (GOF)
t
(HC@N); 1483, 1435, 1168, 693, t(dppe); 1096, 621 t(ClO4);
Largest difference in peak and hole (e Aꢀ3
)
0.446, ꢀ0.339
UV–Vis (CH2Cl2) kmax (nm)(
e
ꢁ 103, Mꢀ1 cmꢀ1): 287 (13.5), 300
R
copper(I) catalyst
N atm, KOt–Bu
N
R
NH
2 X
2 +
2
p-sub.-N-N-diphenylaniline
X= Br, I; R= H, Br, OMe
Scheme 1. Amination reaction catalyzed by copper(I) complexes.

S.S. Chavan et al. / Inorganica Chimica Acta 363 (2010) 3359–3364
3361
move the precipitated base and washed with toluene. The solvent
was removed by rotary evaporator and the crude product obtained
was isolated by silica gel chromatography using (9:1) ether:chloro-
form system. The purified product was then characterized by ele-
mental analysis, IR, 1H NMR and mass spectral studies.
gand charge transfer (MLCT) or ligand centered
[26]. The high energy transitions located in the UV region of the
complexes in the range 260–280 and 290–320 nm are from intral-
p
–
p
* transition
igand p–p* transition.
The 1H NMR spectral data of all copper(I) complexes (1–4) in
CDCl3 are given in the Section 2. Comparison of chemical shift of
uncomplexed ligands with those of copper(I) complexes show that
some of the resonance is shifted up on complexation in each case.
The 1H NMR spectrum of Schiff base ligand L in CDCl3 exhibit a sin-
glet at d 8.10 ppm assigned to imine (HC@N) proton. The downfield
shift of imine proton relative to the corresponding signals in the
free ligand L can be attributed to the deshielding effect resulting
from the coordination of the imine nitrogen [27]. The resonances
of phenyl protons of the coordinated dppe ligand overlap to some
extent with those of phenyl hydrogen atoms of L in the complexes.
However, the broad multiplet observed in the range d 7.18–
8.78 ppm for all the complexes were assigned to the phenyl group
of dppe together with ring proton of Schiff base ligand L. The 1H
NMR spectra of all the complexes exhibit a broad singlet at approx-
imately d 2.67 ppm due to CH2 protons in the dppe ligand.
2.4. X-ray crystallography
A single crystal of complex 4 suitable for X-ray analysis was ob-
tained 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 methods using the SHELXS 93 program and refined by using
SHELXTL 97 software [22]. The non-hydrogen atoms were refined
with anisotropic thermal parameters. All of the hydrogen atoms
were geometrically fixed and refined using a riding model.
3. Results and discussion
3.2. Crystal structure
The reaction of equimolar quantities of copper(I) salt with Schiff
base ligand L in presence of cis-1,2-bis(diphenylphosphino)ethane
(dppe) in dichloromethane solution at room temperature afforded
monomeric mixed ligand complexes of the type [Cu(L)(dppe)]X. All
the complexes are microcrystalline solids that are soluble in com-
mon organic solvents like dichloromethane, chloroform, acetoni-
trile, THF, methanol, ethanol, etc. The results of elemental
analysis (C, H and N) of all copper(I) complexes which are given
in Section 2 confirmed that their stoichiometry and physical prop-
erties are in accordance with the proposed formula. At room tem-
perature all the complexes are diamagnetic, which is characteristic
of the presence of Cu(I) (d10).
The crystals of [Cu(L)(dppe)]BF4 were grown by slow diffusion
of diethyl ether into solution of complex in dichloromethane and
structure was determined by X-ray crystallography. X-ray analysis
revealed that complex crystallizes in triclinic system in an asym-
metric unit cell. The crystallographic data are summarized in Ta-
ble 1 and selected bond angles are given in Table 2. No classical
H-bonding occurs in the crystal structure.
A view of the cation of complex 4, including the atom number-
ing scheme is illustrated in Fig. 1. In the monomeric complex cop-
per(I) exhibits highly distorted tetrahedral coordination geometry,
with the metal atom being surrounded by two nitrogen atoms of
Schiff base (imine nitrogen and pyridine nitrogen) and two phos-
phorous atoms of dppe. The largest deviation from the ideal tetra-
hedral geometry is reflected by the restricting bite angles of the
chelating ligands. The intraligand N(1)–Cu(1)–N(2) and N(2)–
3.1. Spectroscopic properties
The IR spectra of ligands and their complexes are found to be
quite complex as they are in general exhibit large number of bands
on varying intensities. However,
1620 cmꢀ1 in the spectrum of free ligand L corresponds to
(HC@N) group shifted to the lower frequency region by 25–
a strong band observed at
Table 2
0
Selected bond lengths (ÅA) and bond angles (°) for
[Cu(L)(dppe)]BF4 (4).
m
30 cmꢀ1 in the complexes indicate involvement of imine (HC@N)
nitrogen in coordination with metal ion [23]. Another characteris-
tic band observed at 997 cmꢀ1 in L is associated with pyridine ring
breathing mode of vibration. On complexation, this band observed
to higher energy at around 1024–1028 cmꢀ1 in the complexes indi-
cates copper–nitrogen bond formation. This view was further sup-
ported by the appearance of a band corresponding to the metal-
Cu(1)–N(1)
Cu(1)–N(2)
Cu(1)–P(2)
Cu(1)–P(1)
P(1)–C(22)
P(1)–C(16)
P(1)–C(14)
P(2)–C(34)
P(2)–C(28)
P(2)–C(15)
2.0529(17)
2.0745(17)
2.2602(6)
2.2658(6)
1.821(2)
1.822(2)
1.841(2)
1.822(2)
1.826(2)
1.852(2)
nitrogen
m
(Cu–N) stretching vibration at ꢂ482 cmꢀ1 in the com-
plexes [24]. The spectra of all the copper(I) complexes exhibit the
expected bands due to the dppe ligand at around 1483, 1435,
N(1)–Cu(1)–N(2)
N(1)–Cu(1)–P(2)
N(2)–Cu(1)–P(2)
N(1)–Cu(1)–P(1)
N(2)–Cu(1)–P(1)
P(2)–Cu(1)–P(1)
C(22)–P(1)–Cu(1)
C(16)–P(1)–Cu(1)
C(14)–P(1)–Cu(1)
C(34)–P(2)–Cu(1)
C(28)–P(2)–Cu(1)
C(15)–P(2)–Cu(1)
C(1)–N(1)–Cu(1)
C(5)–N(1)–Cu(1)
C(6)–N(2)–C(7)
C(7)–N(2)–Cu(1)
C(6)–N(2)–Cu(1)
80.52(7)
1168 and 693 cmꢀ1. The stretching frequency
m
(C„N) of the cya-
121.64(5)
125.39(5)
120.63(5)
121.37(5)
91.16(2)
121.69(7)
117.02(7)
103.02(7)
117.19(7)
125.05(7)
101.17(7)
130.71(15)
112.47(13)
118.71(18)
128.94(14)
112.35(14)
nide ion in complex 2 occurs at 2110 cmꢀ1. The perchlorate com-
plex 3 exhibit broad band at 1095 cmꢀ1
621 cmꢀ1
(m4), is devoid of any splitting suggesting that the ClO4
(m
3) and strong band at
ꢀ
anion is not coordinated to the copper atom. Howeveꢀr, a broad
band at 1071 cmꢀ1 in 4 corresponds to presence of BF4 anion in
the complex [25].
The electronic spectra of all copper(I) complexes (1–4) in
dichloromethane (10ꢀ4 M) were measured at room temperature.
The electronic spectra of all the complexes are noticeably different
from the spectrum of the free ligand L and also give information
concerning copper–ligand binding in the complexes. In the spectra
of complexes, no d–d transitions are expected for d10 complexes,
the UV–Vis band observed at ꢂ396 nm is assigned to metal to li-

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S.S. Chavan et al. / Inorganica Chimica Acta 363 (2010) 3359–3364
tween P–C (sp2) and P–C (sp3) bond lengths, which are 1.821–
1.826 and 1.841–1.852 Å, respectively.
Torsion angles in the chelating rings, the pyridine group and
aromatic rings of each PPh2 are listed in Table 3. This result dem-
onstrates that the chelating ring Cu(1)–N(1)–C(5)–N(2) is nearly
planar and the pyridine groups are coplanar with the chelate ring.
Despite of the fact that the chelate ring is planar, the sum of three
N atom bond angles is 359.94° N(1) and 360° N(2), however, some
strain in the chelate ring is suggested by the deviation from the
120° angle about the N atom (Cu(1)–N(1)–C(1), 130.71(15)° and
C(7)–N(2)–Cu(1), 128.94(14)°). Moreover, the planes of the two
aromatic rings of each PPh2 moiety are essentially perpendicular
to one another.
3.3. Catalytic properties
Catalytic role of all the copper(I) complexes (1–4) in the amina-
tion of aryl halide was investigated. The system chosen for study is
the coupling of bromobenzene or iodobenzene with different
amines by using 0.05 mmol copper(I) catalyst and KOt–Bu as base
in toluene at 90 °C (Scheme 1). Under this experimental condition
the purified product obtained was characterized by elemental
analysis, IR, 1H NMR and mass spectral studies (Table 4). In order
to check the catalytic effect of Schiff base copper(I) complexes, it
was observed that, when no catalyst was added, the blank reaction
with solvent toluene and KOt–Bu as base exhibited extremely low
reactivity towards the yield of triarylamine with many by-products
from aryl halide substrate. The effect of complex catalysts (1–4) on
the amination of bromobenzene and iodobenzene was investigated
and it was found that copper(I) complexes significantly enhance
the conversion of bromobenzene and iodobenzene into desired
amination product in moderate to good yield. All the reactions
were smoothly carried out at relatively low temperature and
reached the amination yield up to 48–80% (Table 5). No further in-
crease in the yield of the product was observed even when the
reaction time was increased for a longer time.
It was observed that the catalytic amination of bromobenzene
and iodobenzene with aniline reached the amination yield up to
48–69% and 60–72%, respectively. With p-bromoaniline containing
electron withdrawing group at para-position, the amination reac-
tion yield was observed up to 44–64% for bromobenzene and 55–
70% for iodobenzene. However, with p-anisidine containing elec-
tron donating group at para-position, the amination reaction pro-
ceeds with considerable increase in the yield up to 58–74% and
65–80% for bromobenzene and iodobenzene, respectively. These
results confirm that the variety of functional group such as bromo
and methoxy tolerated on arylamine component under the reac-
tion condition. A marginal increase in the yield was observed with
electron donating –OCH3 group at para-position while lower yield
was obtained for electron withdrawing group at para-position of
substituted arylamine [30].
Fig. 1. Molecular structure of [Cu(L)(dppe)]BF4 (4).
Cu(1)–P(1) angles are much less than 109.4°, being 80.52(7)° and
91.16(2)°, respectively. However, the N(1)–Cu(1)–P(2), N(2)–
Cu(1)–P(2), N(1)–Cu(1)–P(1) and P(2)–Cu(1)–P(1) angles are
121.64(5)°, 125.39(5)°, 120.63(5)° and 121.37(5)°, respectively
are much larger than those of a tetrahedral complex. The average
Cu–N bond distance (2.0632 Å) is comparable to those reported
for [Cu(A)(PPh3)2]ClO4 pseudo-tetrahedral complexes [28]. All of
the Cu–P bond lengths are as one would expect, i.e. close to the
average value (2.253 Å) found for bonds between copper and dif-
ferent phosphines such as those found in complex [Cu(dppe)
(NO3)(CH3CN)]n [29]. The quality of data permits to distinguish be-
Table 3
Torsion angles for chelating ring.
N(2)–Cu(1)–N(1)–C(5)
Cu(1)–N(1)–C(5)–C(6)
C(3)–C(4)–C(5)–N(1)
C(3)–C(4)–C(5)–C(6)
Cu(1)–N(2)–C(6)–C(5)
N(1)–C(5)–C(6)–N(2)
C(4)–C(5)–C(6)–N(2)
C(7)–C(8)–C(9)–C(10)
P(1)–C(14)–C(15)–P(2)
Cu(1)–P(2)–C(15)–C(14)
2.64(13)
ꢀ3.7(2)
ꢀ0.5(3)
179.34(19)
ꢀ0.7(2)
3.0(3)
ꢀ176.87(19)
ꢀ177.7(2)
ꢀ55.05(18)
45.49(16)
It was also observed that the efficiency of copper(I) catalyst
with different counter anions exhibit different activities. It is evi-
Table 4
Microanalytical and spectral data of amination product.
Compound
C, H, N found (calculated)
IR (cmꢀ1
)
Mass
1H NMR (d ppm)
C
H
N
N, N-diphenyl-aniline
87.72 (88.13) 6.05 (6.16) 5.87 (5.71) 1587, 1493,
m/z 245 [(Ph)3N]+, 168 [(Ph)2N]+, 77 [Ph]+
d 6.09–6.39, (m, Ar-H)
1461
82.63 (82.88) 6.17 (6.22) 5.68 (5.09) 1586, 1490,
1462
4-Methoxy-N, N-
diphenyl-aniline
m/z 275 [(Ph)3N–OMe]+, 245 [(Ph)3N]+, 168
[(Ph)2N]+, 77 [Ph]+
d 3.86, (s, 3H, OMe), d 6.79–
7.87, (m, Ar-H)
d 6.91–7.32, (m, Ar-H)
4-Bromo-N, N-diphenyl- 67.40 (66.68) 4.23 (4.35) 4.51 (4.32) 1586, 1493,
aniline 1461
m/z 323 [(Ph)3NBr]+, 245 [(Ph)3N]+, 168
[(Ph)2N]+, 77 [Ph]+

S.S. Chavan et al. / Inorganica Chimica Acta 363 (2010) 3359–3364
3363
Table 5
Animation reaction catalyzed by copper(I) complexes.
Entry
Aryl halide
Arylamine
Product
Complex
Yield (%)
1
2
3
4
1
2
3
4
48
55
69
62
Br
NH
2
N
5
6
7
8
1
2
3
4
60
63
72
65
I
NH
2
N
MeO
9
1
2
3
4
58
65
74
68
Br
MeO
NH
NH
2
10
11
12
N
N
MeO
13
14
15
16
1
2
3
4
65
66
80
72
I
MeO
2
Br
17
18
19
20
1
2
3
4
44
51
64
55
Br
Br
NH
2
N
N
Br
21
22
23
24
1
2
3
4
55
59
70
60
I
Br
NH
2
Reaction conditions: Ph–X, 8 mmol; arylamine, 4 mmol; Cu(I) catalyst, 0.05 mmol; KOt–Bu, 12 mmol; toluene, 20 ml; temperature 90 °C;
reaction time 12 h.
ꢀ
dent that the copper(I) complex catalyst with ClO4 anion shows
Appendix A. Supplementary material
greater activities than the complexes with Clꢀ, CNꢀ, BF4 and
ꢀ
reached the amination yield up to 64–80% (Table 5, entries 3, 7,
11, 15, 19 and 23). It was also found that the catalytic activity of
these complexes decreases in the order of ClO4ꢀ > BF4ꢀ > CNꢀ > Clꢀ
as their counter anions. These resultꢀs could be ꢀdue to difference in
coordination ability of Clꢀ, CNꢀ, BF4 and ClO4 with metal ion as
well as difference in solubility of complexes in solvent during the
reaction.
CCDC 762585 contains the supplementary crystallographic data
for [Cu(L)(dppe)]BF4 (4). These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif. Supplementary data associ-
ated with this article can be found, in the online version, at
doi:10.1016/j.ica.2010.06.023.
References
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