Synthesis and characterization of ether-derivatized aminophosphines and their application in C-C coupling reactions

Article abstract of DOI:10.1016/j.ica.2009.12.020

Four new bis(phosphino)amine ligands (Ph₂P)₂N-C₆H₃-R, where R = 3,5-OMe (1), 2,5-OMe (2), 2,4-OMe (3) or 3,4-OMe (4), were prepared via aminolysis of the corresponding dimethoxyanilines with 2 equiv. of diphenylphosphine chloride in the presence of triethyl amine. Oxidation of these ligands with aqueous H₂O₂, elemental S₈ or Se powder afforded the corresponding chalcogen oxides 1a-4a, sulfides 1b-4b and selenides 1c-4c in good yields. Reaction of 1-4 with [MCl₂(cod)] (M = Pt, Pd; cod = cycloocta-1,5-diene) in equimolar ratios afforded cis-[MCl₂{(Ph₂P)₂N-C₆H₃-R}] (M = Pt; R = 3,5-OMe 1d, R = 2,5-OMe 2d, R = 2,4-OMe 3d, and R = 3,4-OMe 4d. M = Pd; R = 3,5-OMe 1e, R = 2,5-OMe 2e, R = 2,4-OMe 3e, and R = 3,4-OMe 4e). Similarly, reaction of [Cu(CH₃CN)₄]PF₆ with the 1-4 in 1:2 ratio gave [Cu{(Ph₂P)₂N-C₆H₃-R}₂]PF₆ (R = 3,5-OMe 1f, 2,5-OMe 2f, 2,4-OMe 3f and 3,4-OMe 4f). All new compounds were fully characterized by spectroscopy and elemental analysis and the molecular structures of seven representative compounds were determined by single-crystal X-ray crystallography. In addition, the palladium complexes were investigated as pre-catalysts in C-C coupling reactions.

Full text of DOI:10.1016/j.ica.2009.12.020

Inorganica Chimica Acta 363 (2010) 1039–1047
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Synthesis and characterization of ether-derivatized aminophosphines
and their application in C–C coupling reactions
a
a
b
b
Nermin Biricik a, , Cezmi Kayan , Bahattin Gümgüm , Zhaofu Fei , Rosario Scopelliti ,
*
b
c
c
_
Paul J. Dyson , Nevin Gürbüz , Ismail Özdemir
a Department of Chemistry, Dicle University of Dicle, 21280 Diyarbakır, Turkey
b Institut de Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
c
_
Department of Chemistry, University of Inönü, 44280 Malatya, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 19 June 2009
Accepted 11 December 2009
Available online 16 December 2009
Four new bis(phosphino)amine ligands (Ph2P)2N-C6H3-R, where R = 3,5-OMe (1), 2,5-OMe (2), 2,4-OMe
(3) or 3,4-OMe (4), were prepared via aminolysis of the corresponding dimethoxyanilines with 2 equiv.
of diphenylphosphine chloride in the presence of triethyl amine. Oxidation of these ligands with aqueous
H2O2, elemental S8 or Se powder afforded the corresponding chalcogen oxides 1a–4a, sulfides 1b–4b and
selenides 1c–4c in good yields. Reaction of 1–4 with [MCl2(cod)] (M = Pt, Pd; cod = cycloocta-1,5-diene)
in equimolar ratios afforded cis-[MCl2{(Ph2P)2N-C6H3-R}] (M = Pt; R = 3,5-OMe 1d, R = 2,5-OMe 2d,
R = 2,4-OMe 3d, and R = 3,4-OMe 4d. M = Pd; R = 3,5-OMe 1e, R = 2,5-OMe 2e, R = 2,4-OMe 3e, and
R = 3,4-OMe 4e). Similarly, reaction of [Cu(CH3CN)4]PF6 with the 1–4 in 1:2 ratio gave [Cu{(Ph2P)2N-
C6H3-R}2]PF6 (R = 3,5-OMe 1f, 2,5-OMe 2f, 2,4-OMe 3f and 3,4-OMe 4f). All new compounds were fully
characterized by spectroscopy and elemental analysis and the molecular structures of seven representa-
tive compounds were determined by single-crystal X-ray crystallography. In addition, the palladium
complexes were investigated as pre-catalysts in C–C coupling reactions.
Keywords:
Aminophosphines
Chalcogenides
X-ray structures
Catalysis
C–C coupling reactions
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
plexes are unstable at elevated temperatures, placing significant
limits on their synthetic utility. Therefore, from a practical point
The synthesis and coordination chemistry of phosphorus(III) li-
gands containing P–N linkages continues to receive widespread
attention [1,2]. In particular, bis(phosphino)amines including
(diphenylphosphino)aniline derivatives are frequently encoun-
tered due to their facile synthesis, relatively high stability [3] and
applications in catalysis [4]. Indeed, an extensive library of P–N
bond containing ligands has been constructed [5,6]. Functionaliza-
tion of the aminophosphines allows their electronic and steric
properties to be tuned which in turn modulates catalytic activity.
In addition, the oxidized forms of the bis(phosphino)amine
RN(P(:E)R2)2 (where E = O, S or Se) can be used as precursors in
the synthesis of small-membered ring systems [7].
Palladium-catalysed couplings have become an indispensable
tool in organic synthesis [8] since they are tolerant to a wide vari-
ety of functional groups. Over the years studies have revealed the
crucial role played by the ancillary ligands in the efficiency of these
reactions. For example, electron-rich alkyl-phosphines [9] and
carbenes [10] have received increasing interest in recent years,
but the phosphine ligands and the phosphine–palladium com-
of view, the development of more stable ligands leading to more
reactive catalysts is of importance.
The ancillary ligands coordinated to a metal center have a num-
ber of important roles in homogeneous catalysis, not only provid-
ing a stabilizing effect, but also governing activity and selectivity.
Recently it has been shown that N,N-bis(diphenylphosphino)ani-
line palladium(II) complexes offer distinctive benefits in Heck cou-
pling reactions [11,12]. In a continuation of our studies on
aminophosphines [13,14], we decided to prepare a series of
bis(phosphino)amines possessing electron-donating methoxy-sub-
stituents on an aryl ring and explore their chemistry and catalytic
function when coordinated to palladium, and we report the out-
come of these studies herein.
2. Experimental
All manipulations were performed under an inert atmosphere of
dry argon. Solvents were dried using the appropriate reagents and
distilled prior to use. The starting materials [MCl2(cod)] (M = Pt,
Pd; cod = cycloocta-1,5-diene) [15,16] and [Cu(CH3CN)4]PF6 [17]
were prepared according to literature procedures. Other starting
materials are commercially available and were used as received.
* Corresponding author.
E-mail address: nbiricik@dicle.edu.tr (N. Biricik).
0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2009.12.020

1040
N. Biricik et al. / Inorganica Chimica Acta 363 (2010) 1039–1047
NMR spectra were obtained on a Bruker Avance 400 spectrometer
operating at the appropriate frequencies using SiMe4 (for 1H and
13C) as internal and 85% H3PO4 (for 31P) as external reference. IR
spectra were recorded on a Mattson 1000 ATI UNICAM FT-IR spec-
trometer in the range 4000–400 cmꢀ1 in KBr matrices. Elemental
analysis was carried out using a Fisons EA 1108 CHNS-O instru-
ment. Melting points were determined in capillary tubes on a Gal-
lenkamp MID 350 BM 2.5 apparatus.
2.3. General procedure for synthesis of 1a–4a
A thf (10 ml) solution of the N,N-bis(diphenylphosphino)dime-
thoxyaniline (1–4) (0.100 g, 0.192 mmol) and aqueous H2O2 (30%
w/w, 0.435 g, 0.383 mmol) was stirred for 1 h. The solution was
evaporated to dryness under reduced pressure to give the corre-
sponding oxide derivative (1a–4a) as a solid.
2.3.1. N,N-Bis(diphenyloxophosphino)-3,5-dimethoxyaniline,
[(Ph2P(O))2N-C6H3-(3,5-OCH3)] (1a)
2.1. General procedure for preparation of 1–3
Yield: 0.0816 g, (76.9%). Mp. 212–213 °C. Anal. Calc. for
C32H29NO4P2: C, 69.44; H, 5.28; N, 2.53%. Found: C, 69.53; H,
5.23; N, 2.40%. 31P NMR (ppm, CDCl3): d 22.0 (s). 1H NMR (ppm,
CDCl3): d 5.95 (s, 1H), 6.68 (s, 2H), 7.21–7.89 (m, 20H, Ar), 3.58
Ph2PCl (2.88 g, 13.1 mmol) was added to a solution of the dime-
thoxyaniline (1.00 g, 6.53 mmol) and NEt3 (1.45 g, 14.3 mmol) in
CH2Cl2 (25 ml) at 0 °C. The resulting suspension was stirred for
1 h and then the solvent was removed under reduced pressure.
The remaining solid was washed with distilled water and then
with diethyl ether, and dried under vacuum.
(s, 6H, CH3). IR data (cmꢀ1):
920 (P–N).
t 2845 (CH of OMe), 1202 (P–O),
2.3.2. N,N-Bis(diphenyloxophosphino)-2,5-dimethoxyaniline,
[(Ph2P(O))2N-C6H3-(2,5-OCH3)] (2a)
2.1.1. N,N-Bis(diphenylphosphino)-3,5-dimethoxyaniline,
[(Ph2P)2N-C6H3-(3,5-OCH3)] (1)
Yield: 0.0971 g, (91.5%). M.p. 165–167 °C. Anal. Calc. for
C32H29NO4P2: C, 69.44; H, 5.28; N, 2.53. Found: C, 69.38; H, 5.20;
N, 2.38%. 31P NMR (ppm, CDCl3): d 26.1 (s). 1H NMR (ppm, CDCl3):
d 6.25 (d, 1H), 6.47 (d, 1H), 7.11 (s, 1H), 7.25–7.93 (m, 20H, Ar),
Yield: 2.63 g, (77.4%). M.p. 130–132 °C. Anal. Calc. for
C32H29NO2P2: C, 73.70; H, 5.61; N, 2.69. Found: C, 73.91; H, 5.65;
N, 2.61%. 31P NMR (ppm, CDCl3): d 68.6 (s). 1H NMR (ppm, CDCl3):
d 5.80 (s, 2H), 6.13 (s, 1H), 7.30–7.41 (m, 20H, Ar), 3.36 (s, 6H, CH3).
13C NMR (ppm, CDCl3): d CArm, 160.0, 149.0, 139.2, 133.3, 129.1,
3.56 (s, 3H, CH3), 3.51 (s, 3H, CH3). IR data (cmꢀ1):
OMe), 1221 (P–O), 958 (P–N).
t 2839 (CH of
128.0, 107.2, 98.5. COCH , 55.0. IR (cmꢀ1):
t 2831 (CH of OMe),
3
915 (P–N).
2.3.3. N,N-Bis(diphenyloxophosphino)-2,4-dimethoxyaniline,
[(Ph2P(O))2N-C6H3-(2,4-OCH3)] (3a)
2.1.2. N,N-Bis(diphenylphosphino)-2,5-dimethoxyaniline,
[(Ph2P)2N-C6H3-(2,5-OCH3)] (2)
Yield: 0.0758 g, (71.4%). M.p. 205–207 °C. Anal. Calc. for
C32H29NO4P2: C, 69.44; H, 5.28; N, 2.53. Found: C, 69.41; H, 5.18;
N, 2.46%. 31P NMR (ppm, CDCl3): d 25.1 (s). 1H NMR (ppm, CDCl3):
d 5.85 (d, 1H), 6.20 (d, 1H), 7.21–7.95 (m, 21H, Ar) 3.63 (s, 3H, CH3),
Yield: 2.51 g, (73.8%). M.p. 147–149 °C. Anal. Calc. for
C32H29NO2P2: C, 73.70; H, 5.61; N, 2.69. Found: C, 73.89; H, 5.63;
N, 2.66%. 31P NMR (ppm, CDCl3): d 64.7 (s). 1H NMR (ppm, CDCl3):
d 6.33 (s, 1H), 6.65 (s, 2H), 7.33 (broad singlet, 20 H, Ar), 3.38 (s, 3H,
CH3), 3.32 (s, 3H, CH3). 13C NMR (d ppm, CDCl3): CArm, 152.7, 150.4,
3.48 (s, 3H, CH3). IR data (cmꢀ1):
958 (P–N).
t 2841 (CH of OMe), 1228 (P–O),
140.1, 137.6, 133.4, 128.7, 127.8, 115.8, 112.4, 112.1. COCH , 55.4,
3
55.0. IR (cmꢀ1):
t 2840 (CH of OMe), 896 (P–N).
2.3.4. N,N-Bis(diphenyloxophosphino)-3,4-dimethoxyaniline,
[(Ph2P(O))2N-C6H3-(3,4-OCH3)] (4a)
Yield: 0.0535 g, (50.4%). M.p. 131–133 °C. Anal. Calc. for
C32H29NO4P2: C, 69.44; H, 5.28; N, 2.53. Found: C, 69.35; H, 5.24;
N, 2.37%. 31P NMR (ppm, CDCl3): d 29.5 (s). 1H NMR (ppm, CDCl3):
d 6.43 (d, 1H), 6.65 (s,1H), 6.86 (s,1H), 7.05–7.92 (m, 20H, Ar), 3.75
2.1.3. N,N-Bis(diphenylphosphino)-2,4-dimethoxyaniline,
[(Ph2P)2N-C6H3-(2,4-OCH3)] (3)
Yield: 2.26 g, (66.5%). M.p. 120–121 °C. Anal. Calc. for
C32H29NO2P2: C, 73.70; H, 5.61; N, 2.69. Found: C, 73.95, H, 5.68;
N, 2.59%. 31P NMR (ppm, CDCl3): d 66.1 (s). 1H NMR (ppm, CDCl3):
d 6.15 (q, 1H), 6.23 (d, 1H), 6.70 (d, 1H), 7.28–7.52 (m, 20H, Ar),
(s, 3H, CH3), 3.64 (s, 3H, CH3). IR data (cmꢀ1):
1196 (P–O), 968 (P–N).
t 2838 (CH of OMe),
3.74 (s, 3H, CH3), 3.27 (s, 3H, CH3). 13C NMR (d ppm, CDCl3): CArm
,
2.4. General procedure for synthesis of 1b–4b and 1c–4c
158.6, 156.8, 134.6, 132.3, 131.3, 130.5, 130.4, 127.8, 103.2, 99.0,
COCH , 55.4; 54.3. IR (cmꢀ1):
t 2837 (CH of OMe), 835 (P–N).
3
Elemental sulfur (0.0123 g, 0.384 mmol) was added to a solu-
tion of N,N-bis(diphenylphosphino)dimethoxyaniline (1–4)
(0.100 g, 0.192 mmol) in thf (10 ml) and the reaction mixture
was heated to reflux for 5 h. The volume of the solvent was concen-
trated in vacuo to 1–2 ml and addition of n-hexane (15 ml) gave
the sulfide derivative (1b–4b) as a solid which was collected by fil-
tration. In a similar manner the selenide derivatives were synthe-
sized from 1–4 (0.100 g, 0.192 mmol) and selenium powder
(0.0303 g, 0.384 mmol).
2.2. Preparation of N,N-bis(diphenylphosphino)-3,4-dimethoxyaniline,
[(Ph2P)2N-C6H3-(3,4-OCH3)] (4)
Ph2PCl (2.88 g, 13.1 mmol) was added to a solution of the 3,4-
dimethoxyaniline (1.00 g, 6.53 mmol) and NEt3 (1.45 g, 14.3 mmol)
in tetrahydrofurane (25 ml) at 0 °C. The resulting suspension was
stirred for 1 h and then filtered in vacuo to separate the Et3NꢁHCl
salt by-product. The solvent was removed under reduced pressure
and the remaining viscous product was washed with a small
amount of diethyl ether and dried under vacuum.
2.4.1. N,N-Bis(diphenylthiophosphino)-3,5-dimethoxyaniline,
[(Ph2P(S))2N-C6H3-(3,5-OCH3)] (1b)
Anal. Calc. for C32H29NO2P2: C, 73.70; H, 5.61; N, 2.69. Found: C,
73.87; H, 5.64; N, 2.56%. 31P NMR (ppm, CDCl3): d 71.1 (s). 1H NMR
(ppm, CDCl3): d 5.84 (s, 1H), 6.20 (d, 1H), 6.45 (d, 1H), 7.29–7.35
(m, 20 H, Ar), 3.74 (s, 3H, CH3), 3.18 (s, 3H, CH3). 13C NMR (d
ppm, CDCl3): CArm, 147.7, 146.6, 139.7, 139.4, 133.4, 129.1, 128.0,
Yield: 0.0634 g, (56.5%). M.p 237–238 °C. Anal. Calc. for
C32H29NO2P2S2: C, 65.63; H, 4.99; N, 2.39; S, 10.94. Found: C,
65.56; H, 4.81; N, 2.35; S, 10.88%. 31P NMR (ppm, CDCl3): d 68.4
(s). 1H NMR (ppm, CDCl3): d 5.94 (s, 1H), 7.04 (s, 2H), 7.23–8.14
121.4, 113.4, 110.2, (COCH , 55.8, 55.1. IR data (cmꢀ1):
t
2839 (CH
(m, 20H, Ar), 3.56 (s, 6H, CH3). IR data (cmꢀ1):
OMe), (920) P–N, 654 (P–S).
t 2839 (CH of
3
of OMe), 910 (P–N).

N. Biricik et al. / Inorganica Chimica Acta 363 (2010) 1039–1047
1041
2.4.2. N,N-Bis(diphenylthiophosphino)-2,5-dimethoxyaniline,
[(Ph2P(S))2N-C6H3-(2,5-OCH3)] (2b)
ume of the solvent was concentrated to 1–2 ml under reduced
pressure and addition of Et2O (15 ml) gave the platinum complexes
(1d–4d) as solids which were isolated by filtration and dried in va-
cuo. In a similar manner the palladium complexes (1e–4e) were
prepared from 1–4 (0.100 g, 0.192 mmol) and [PdCl2(cod)]
(0.0546 g, 0.192 mmol).
Yield: 0.0397 g, (70.7%). M.p. 215–217 °C. Anal. Calc. for
C32H29NO2P2S2: C, 65.63; H, 4.99; N, 2.39; S, 10.94. Found: C,
65.68; H, 4.86; N, 2.32; S, 10.85%. 31P NMR (ppm, CDCl3): d 67.5
(s). 1H NMR (ppm, CDCl3): d 6.07 (d, 1H), 6.49 (d, 1H), 6.93 (s,
1H), 7.14–7.95 (m, 20H, Ar), 3.44 (s, 3H, CH3), 3.22 (s, 3H, CH3).
IR data (cmꢀ1):
t 2839 (CH of OMe), 920 (P–N), 656 (P–S).
2.5.1. {N,N-Bis(diphenylphosphino)-3,5-
dimethoxyaniline}platinum(II)chloride, [PtCl2{(Ph2P)2N-C6H3-
(3,5-OMe)}] (1d)
2.4.3. N,N-Bis(diphenylthiophosphino)-2,4-dimethoxyaniline,
[(Ph2P(S))2N-C6H3-(2,4-OCH3)] (3b)
Yield: 0.118 g, (78.1%). M.p. 315–316 °C. Anal. Calc. for
C32H29NO2P2PtCl2: C, 48.81; H, 3.71; N, 1.78. Found: C, 48.72; H,
Yield: 0.0706 g, (62.9%). M.p. 197–199 °C. Anal. Calc. for
C32H29NO2P2S2: C, 65.63; H, 4.99; N, 2.39; S, 10.94. Found: C,
65.53; H, 4.83; N, 2.29; S, 10.79%. 31P NMR (ppm, CDCl3): d 67.9
(s). 1H NMR (ppm, CDCl3): d 5.69 (d, 1H), 6.08 (q, 1H). 7.14–8.18
1
3.66; N, 1.71%. 31P NMR (ppm, CDCl3): d 20.0 (t); JPt–P: 3414 Hz.
1H NMR (ppm, CDCl3): d 5.60 (s, 2H), 6.24 (s, 1H), 7.51–7.91 (m,
20H, Ar), 3.35 (s, 6H, CH3). IR data (cmꢀ1):
901 (P–N).
t 2841 (CH of OMe),
(m, 21H,Ar), 3.59 (s, 3H, CH3), 3.20 (s, 3H, CH3). IR data (cmꢀ1):
2837 (CH of OMe), 908 (P–N), 700 (P–S).
t
2.5.2. {N,N-Bis(diphenylphosphino)-2,5-
dimethoxyaniline}platinum(II)chloride, [PtCl2{(Ph2P)2N-C6H3-
(2,5-OMe)}] (2d)
2.4.4. N,N-Bis(diphenylthiophosphino)-3,4-dimethoxyaniline,
[(Ph2P(S))2N-C6H3-(3,4-OCH3)] (4b)
Yield: 0.0551 g, (49.1%). M.p. >200 °C (dec.) Anal. Calc. for
C32H29NO2P2S2: C, 65.63; H, 4.99; N, 2.39; S, 10.94. Found: C,
65.49; H, 4.87, N, 2.28; S, 10.86%. 31P NMR (ppm, CDCl3): d 73.6
(s). 1H NMR (ppm, CDCl3): d 6.36–8.13 (m, 23H, Ar), 3.65 (d, 6H,
Yield: 0.132 g, (87.4%). M.p. 309–311 °C. Anal. Calc. for
C32H29NO2P2PtCl2: C, 48.81; H, 3.71; N, 1.78. Found: C, 48.75; H,
3.67; N, 1.73%. 31P NMR (ppm, CDCl3): d 22.9 (t). JPt–P: 3344 Hz.
1
1H NMR (ppm, CDCl3): d 5.68 (d, 1H), 6.58 (d, 1H), 6.75 (d, 1H),
CH3). IR data (cmꢀ1):
t 2831 (CH of OMe), 949 (P–N), 725 (P–S).
7.47–7.92 (m, 20H), 3.24 (s, 3H, CH3), 2.94 (s, 3H, CH3). IR data
(cmꢀ1):
t 2837 (CH of OMe), 908 (P–N).
2.4.5. N,N-Bis(diphenylselenophosphino)-3,5-dimethoxyaniline,
[(Ph2P(Se))2N-C6H3-(3,5-OCH3)] (1c)
Yield: 0.0658 g, (50.5%). M.p. 215–216 °C. Anal. Calc. for
C32H29NO2P2Se2: C, 56.57; H, 4.30; N, 2.06. Found: C, 56.45, H,
2.5.3. {N,N-Bis(diphenylphosphino)-2,4-
dimethoxyaniline}platinum(II)chloride, [PtCl2{(Ph2P)2N-C6H3-
(2,4-OMe)}] (3d)
1
4.21, N, 1.99%. 31P NMR (ppm, CDCl3): d 69.1 (s). JP–Se: 796 Hz.
1H NMR (ppm, CDCl3): d 5.96 (s, 1H), 7.09 (s, 2H), 7.22–8.21 (m,
Yield: 0.111 g, (73.5%). M.p. >200 °C (dec.) Anal. Calc. for
C32H29NO2P2PtCl2: C, 48.81; H, 3.71; N, 1.78. Found: C, 48.69; H,
20H, Ar), 3.57 (s, 6H, CH3). IR data (cmꢀ1):
915 (P–N), 558 (P–Se).
t 2840 (CH of OMe),
3.64; N, 1.68%. 31P NMR (ppm, DMSO-d6): d 22.5 (t). JPt–P
:
3229 Hz. 1H NMR (ppm, DMSO-d6): d 6.25 (t, 2H), 6.43 (d, 1H),
2.4.6. N,N-Bis(diphenylselenophosphino)-2,5-dimethoxyaniline,
[(Ph2P(Se))2N-C6H3-(2,5-OCH3)] (2c)
7.40–7.81 (m, 20H, Ar), 3.66 (s, 3H, CH3), 2.80 (s, 3H, CH3). IR data
(cmꢀ1):
t 2839 (CH of OMe), 891 (P–N).
Yield: 0.0917 g, (70.4%). M.p. 175–177 °C. Anal. Calc. for
C32H29NO2P2Se2: C, 56.57; H, 4.30; N, 2.06. Found: C, 56.49; H,
4.20; N, 1.97%. 31P NMR (ppm, CDCl3): d 65.2 (s). JP–Se: 807 Hz. 1H
NMR (ppm, CDCl3): d 6.03 (d, 1H), 6.50 (d, 1H), 7.01 (d, 1H),
7.12–7.94 (m, 20H, Ar), 3.46 (s, 3H, CH3), 3.17 (s, 3H, CH3). IR data
2.5.4. {N,N-Bis(diphenylphosphino)-3,4-
dimethoxyaniline}platinum(II)chloride, [PtCl2{(Ph2P)2N-C6H3-
(3,4-OMe)}] (4d)
Yield: 0.134 g, (88.7%). M.p. >240 °C (dec.) Anal. Calc. for
C32H29NO2P2PtCl2: C, 48.81; H, 3.71; N, 1.78. Found: C, 48.66, H,
(cmꢀ1):
t 2839 (CH of OMe), 914 (P–N), 560 (P–Se).
3.61; N, 1.65%. 31P NMR (ppm, CDCl3): d 25.3 (t). JP–Pt: 3325 Hz.
1
1H NMR (ppm, CDCl3): d 6.33–7.78 (m, 23H, Ar), 3.61 (d, 6H,
2.4.7. N,N-Bis(diphenylselenophosphino)-2,4-dimethoxyaniline,
[(Ph2P(Se))2N-C6H3-(2,4-OCH3)] (3c)
CH3). IR data (cmꢀ1):
t 2835 (CH of OMe), 913 (P–N).
Yield: 0.0738 g, (61.4%). M.p. 231–233 °C. Anal. Calc. for
C32H29NO2P2Se2: C, 56.57; H, 4.30; N, 2.06. Found: C, 56.40, H,
1
2.5.5. {N,N-Bis(diphenylphosphino)-3,5-
dimethoxyaniline}palladium(II)chloride, [PdCl2{(Ph2P)2N-C6H3-
(3,5-OMe)}] (1e)
4.18, N, 1.94%. 31P NMR (ppm, CDCl3): d 65.9 (s). JP–Se: 802 Hz.
1H NMR (ppm, CDCl3): d 5.67 (d, 1H), 6.10 (q, 1H), 7.09–7.89 (m,
21H, Ar), 3.62 (s, 3H, CH3), 3.19 (s, 3H, CH3). IR data (cmꢀ1):
2838 (CH of OMe), 906 (P–N), 571 (P–Se).
t
Yield: 0.104 g, (77.6%). M.p. 289–290 °C. Anal. Calc. for
C32H29NO2P2PdCl2: C, 55.00; H, 4.18; N, 2.00. Found: C, 55.21, H,
4.25; N, 1.89%. 31P NMR (ppm, CDCl3): d 34.1 (s). 1H NMR (ppm,
CDCl3): d 5.66 (s, 2H), 6.23 (s, 1H), 7.52–7.98 (m, 20H, Ar), 3.37
2.4.8. N,N-Bis(diphenylselenophosphino)-3,4-dimethoxyaniline,
[(Ph2P(Se))2N-C6H3-(3,4-OCH3)] (4c)
(s, 6H, CH3). IR data (cmꢀ1):
t 2839 (CH of OMe), 909 (P–N).
Yield: 0.0919 g, (76.5%). M.p. >200 °C (dec.) Anal. Calc. for
C32H29NO2P2Se2: C, 56.57; H, 4.30; N, 2.06. Found: C, 56.38, H,
1
4.17; N, 1.92%. 31P NMR (ppm, CDCl3): d 69.8 (s). JP–Se: 805 Hz.
2.5.6. {N,N-Bis(diphenylphosphino)-2,5-
dimethoxyaniline}palladium(II)chloride, [PdCl2{(Ph2P)2N-C6H3-
(2,5-OMe)}] (2e)
1H NMR (ppm, CDCl3): d 6.35–8.24 (m, 23H, Ar), 3.65 (d, 6H,
CH3). IR data (cmꢀ1):
t 2835 (CH of OMe), 911 (P–N), 554 (P–Se).
Yield: 0.0967 g, (72.2%). M.p. 285–287 °C. Anal. Calc. for
C32H29NO2P2PdCl2: C, 55.00; H, 4.18; N, 2.00. Found: C, 55.13; H,
4.19; N, 1.88%. 31P NMR (ppm, CDCl3): d 38.2 (s). 1H NMR (ppm,
CDCl3): d 5.77 (s, 1H), 6.59 (d, 1H), 6.76 (d, 1H), 7.46–7.98 (m,
2.5. General procedure for synthesis of 1d–4d and 1e–4e
A solution of [PtCl2(cod)] (0.0717 g, 0.192 mmol) and N,N-
bis(diphenylphosphino)
dimethoxyaniline
(1–4)
(0.100 g,
20H, Ar), 3.25 (s, 3H, CH3), 2.98 (s, 3H, CH3). IR data (cmꢀ1):
2837 (CH of OMe), 908 (P–N).
t
0.192 mmol) in CH2Cl2 (10 ml) was stirred at RT for 1 h. The vol-

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N. Biricik et al. / Inorganica Chimica Acta 363 (2010) 1039–1047
2.5.7. {N,N-Bis(diphenylphosphino)-2,4-
2.7. General procedure for the Heck coupling reactions
dimethoxyaniline}palladium(II)chloride, [PdCl2{(Ph2P)2N-C6H3-
(2,4-OMe)}] (3e)
The palladium pre-catalyst (1e–4e, 1.0%), aryl bromide
(1.0 mmol), styrene (1.5 mmol), K2CO3 (2 mmol) and dioxane
(3 ml) were added to a Schlenk tube and the mixture was heated
to 80 °C for 6 h. The reaction mixture was cooled to RT, and the
products extracted with ethyl acetate/hexane (1:5), filtered
through a pad of silica gel with copious washing, concentrated
and purified by flash chromatography on silica gel. The purity of
the compounds was checked by 1H NMR and GC, and the yields
are based on the aryl bromide.
Yield: 0.111 g, (82.8%). M.p. 281–283 °C. Anal. Calc. for
C32H29NO2P2PdCl2: C, 55.00; H, 4.18; N, 2.00. Found: C, 55.07, H,
4.16, N, 1.93%. 31P NMR (ppm, DMSO-d6): d 37.9 (s). 1H NMR
(ppm, DMSO-d6): d 6.26 (t, 2H), 6.47 (d, 1H), 7.62–7.83 (m, 20H,
Ar), 3.66 (s, 3H, CH3), 2.81 (s, 3H, CH3). IR data (cmꢀ1):
(CH of OMe), 893 (P–N).
t 2837
2.5.8. {N,N-Bis(diphenylphosphino)-3,4-
dimethoxyaniline}palladium(II)chloride, [PdCl2{(Ph2P)2N-C6H3-
(3,4-OMe)}] (4e)
2.8. General procedure for the Suzuki coupling reactions
Yield: 0.119 g, (88.8%). M.p. >240 °C (dec.) Anal. Calc. for
C32H29NO2P2PdCl2: C, 55.00; H, 4.18; N, 2.00. Found: C, 55.16; H,
4.22; N, 1.94%. 31P NMR (ppm, DMSO-d6): d 34.9 (s). 1H NMR
(ppm, DMSO-d6): d 5.45 (s, 1H), 6.40 (d, 1H), 6.79 (d, 1H), 7.69–
The palladium pre-catalyst (1e–4e, 1.0%), aryl bromide
(1.0 mmol), phenylboronic acid (1.5 mmol), Cs2CO3 (2 mmol),
dioxane (3 ml) were added to a small Schlenk tube in air and the
mixture was heated to 80 °C for 2 h. The reaction mixture was
cooled to RT, extracted with ethyl acetate/hexane (1:5), filtered
through a pad of silicagel with copious washing, concentrated
and purified by flash chromatography on silica gel. The purity of
the compounds was checked by GC and 1H NMR, and yields are
based on the aryl bromide.
7.85 (m, 20H, Ar), 3.63 (d, 6H, CH3). IR data (cmꢀ1):
of OMe), 926 (P–N).
t 2839 (CH
2.6. General procedure for preparation of 1f–4f
To a solution of N,N-bis(diphenylphosphino)dimethoxyaniline
(1–4) (0.100 g, 0.192 mmol) in CH2Cl2 (10 ml), [Cu(CH3CN)4]PF6
(0.0357 g, 0.096 mmol) was added and the resulting solution was
stirred at RT for 1 h. The majority of solvent was removed under re-
duced pressure and addition of Et2O (15 ml) gave the correspond-
ing copper complexes (1f–4f) as solids which were isolated by
filtration, washed with Et2O (5 ml) and dried in vacuo.
2.9. Crystallography
Data collection for the crystal structures were performed at low
temperature using Mo Ka radiation. An Oxford Diffraction Sap-
phire/KM4 CCD was employed for 2b, 1d, 3d, 3e, 4e and the
remaining crystals were measured on a Bruker APEX II CCD. Both
diffractometers have a kappa geometry goniometer. Data were re-
duced using CRYSALIS PRO [18] (2b, 1d, 3d, 3e, 4e), and EvalCCD [19]
(1c, 1e) and then corrected for absorption [20] Solution and refine-
ment for all crystal structures were performed by SHELXTL [21]. All
structures were refined using full-matrix least-squares on F2 with
all non hydrogen atoms anisotropically defined. Hydrogen atoms
were placed in calculated positions by means of the ‘‘riding” mod-
el. Relevant crystallographic data are compiled in Table 1.
2.6.1. Bis[N,N-bis(diphenylphosphino)-3,5-
dimethoxyaniline)copper(1)] hexafluorophosphate,
[Cu{Ph2P)2N-C6H3-(3,5-OMe)}2]PF6 (1f)
Yield: 0.0970 g, (80.8%). M.p. 191–193 °C. Anal. Calc. for
C64H58N2O4P5F6Cu: C, 61.42; H, 4.67; N, 2.24. Found: C, 61.53; H,
4.75; N, 2.13%. 31P NMR (ppm, CDCl3): d 87.6 (s). d(PF6): ꢀ144.5
1
(m). JP–F: 711 Hz. 1H NMR (ppm, CDCl3): d 5.45 (s, 2H), 6.18 (s,
1H), 7.30–7.52 (m, 20H, Ar), 3.25 (s, 6H, CH3). IR data (cmꢀ1):
2837 (CH of OMe), 844 (P–N).
t
2.6.2. Bis[N,N-bis(diphenylphosphino)-2,5-
dimethoxyaniline)copper(1)] hexafluorophosphate,
[Cu{Ph2P)2N-C6H3-(2,5-OMe)}2]PF6 (2f)
3. Results and discussion
Aminolysis of chlorophosphines is an efficient method for pre-
paring aminophosphines of general formula R2PN(H)R0 or
(R2P)2NR0 [22]. The outcome of the aminolysis reaction is influ-
enced by the amine, the nature of the auxiliary base, and the sol-
vent [23]. For the synthesis of the new bis(phosphino)amine
ligands (Ph2P)2N-C6H3-R (R = 3,5-OMe 1, 2,5-OMe 2, 2,4-OMe 3,
3,4-OMe 4) aminolysis was achieved using Et3N as the auxiliary
base in dichloromethane (Scheme 1). The reaction also proceeds
in diethyl ether but at considerably increased reaction times. The
reaction in dichloromethane was monitored by 31P NMR spec-
troscopy and completed within 1 h. Ligands 1–3 are air-stable
solids that can even be purified by washing with water. In con-
trast, 4 is very sensitive towards moisture and rapidly decom-
poses upon exposure the air. The 31P NMR spectra of 1–4
display singlet resonances at d 68.6, 64.7, 66.1 and 71.1 ppm,
respectively, these values being within the range found in struc-
turally similar compounds [3,5,28]. The 1H NMR spectra of 1–4
verify that complete N–H substitution has taken place and the
13C NMR spectra further corroborate the proposed structures.
Other pertinent spectroscopic and analytical data are given in
Section 2.
Yield: 0. 101 g, (84.2%). M.p. 204–206 °C. Anal. Calc. for
C64H58N2O4P5F6Cu: C, 61.42; H, 4.67; N, 2.24. Found: C, 61.37, H,
4.61; N, 2.07%. 31P NMR (ppm, CDCl3): d 88.8 (s). d(PF6): ꢀ144.3,
1JP–F: 712 Hz. 1H NMR (ppm, CDCl3): d 5.78 (s, 1H), 6.42 (d, 1H),
6.63 (d, 1H), 7.27–7.47 (m, 20H, Ar), 3.21 (s, 3H, CH3), 2.75 (s,
3H, CH3). IR data (cmꢀ1):
t 2839 (CH of OMe), 900 (P–N).
2.6.3. Bis[N,N-bis(diphenylphosphino)-2,4-
dimethoxyaniline)copper(1)] hexafluorophosphate,
[Cu{Ph2P)2N-C6H3-(2,4-OMe)}2]PF6 (3f)
Yield: 0.103 g, (85.8%). m.p. >200 °C (dec.) Anal. Calc. for
C64H58N2O4P5F6Cu: C, 61.42; H, 4.67; N, 2.24. Found: C, 61.49, H,
4.69; N, 2.10%. 31P NMR (ppm, CDCl3): d 89.0 (s). d(PF6): ꢀ144.3,
JP–F: 712 Hz. 1H NMR (ppm, DMSO-d6): d 6.10 (q, 2H), 6.24 (d,
1H), 7.26–7.54 (m, 20H, Ar), 3.61 (s, 3H, CH3), 2.67 (s, 3H, CH3).
IR data (cmꢀ1):
t 2837 (CH of OMe), 888 (P–N).
2.6.4. Bis[N,N-bis(diphenylphosphino)-3,4-
dimethoxyaniline)copper(1)] hexafluorophosphate,
[Cu{Ph2P)2N-C6H3-(3,4-OMe)}2]PF6 (4f)
Complex 4f could not be isolated in pure form. It decomposes
rapidly. 31P NMR (reaction medium, ppm, CDCl3): d 87.6 (s).
d(PF6): ꢀ144.3, JP–F: 712 Hz.
Oxidation of 1–4 with aqueous H2O2, elemental sulfur or sele-
nium powder in thf gave the corresponding oxides 1a–4a, sulfides
1b–4b and selenides 1c–4c (Scheme 1) which were characterized

N. Biricik et al. / Inorganica Chimica Acta 363 (2010) 1039–1047
1043
Table 1
Crystal data and details of the structure determination for: 1c, 2b, 1d, 1e, 3d, 3e, 4e.
1c
2b
1d
1e
3d
3e
4e
Chemical formula
Formula weight
Crystal system
Space group
a (Å)
C32H29NO2P2Se2 C32H29NO2P2S2 C33H31Cl4NO2P2Pt C33H31Cl4NO2P2Pd C33H31Cl4NO2P2Pt C33H31Cl4NO2P2Pd C32H29Cl2NO2P2Pd
679.42
585.62
monoclinic
P21/n
872.42
monoclinic
P21/c
783.73
monoclinic
P21/c
872.42
monoclinic
P21/m
783.73
monoclinic
P21/m
698.80
monoclinic
P21
triclinic
ꢀ
P1
10.2911(7)
12.5722(4)
12.8041(10)
90.435(5)
103.529(6)
113.087(5)
1472.49(16)
2
11.4109(3)
15.8705(3)
16.7331(3)
90
104.136(2)
90
12.6683(2)
14.6175(2)
18.6772(3)
90
102.8190(15)
90
12.6796(12)
14.5834(11)
18.6795(16)
90
102.323(8)
90
8.7362(6)
16.1198(8)
12.0028(8)
90
109.248(5)
90
8.7055(5)
16.1646(7)
11.9720(7)
90
109.050(7)
90
8.7866(2)
20.5582(4)
9.1715(2)
90
111.509(3)
90
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
2938.55(11)
4
3372.42(9)
4
3374.5(5)
4
1595.82(18)
2
1592.45(15)
2
1541.34(6)
2
Z
Dcalc (g cmꢀ3
F(0 0 0)
)
1.532
1.324
1.718
1.543
1.816
1.634
1.506
684
1224
1712
1584
856
792
708
l
(mmꢀ1
)
2.650
0.321
4.604
0.993
4.865
1.052
0.909
T (K)
100
140
140
100
140
140
140
Wavelength (Å)
0.71073
33 475
6737
0.71073
24 415
5964
0.71073
21 014
5713
0.71073
78 418
7747
0.71073
13 826
3352
0.71073
11 098
3221
0.71073
13 691
5739
Measured reflections
Unique reflections
Unique reflections
5307
4428
5201
5247
2583
2971
5058
[I > 2r(I)]
Data/parameters
6737/352
0.0363
0.0645
1.132
5964/352
0.0337
0.0807
1.010
5713/419
0.0207
0.0530
1.032
7747/416
0.0709
0.1170
1.160
3352/214
0.0404
0.0838
0.949
3221/214
0.0501
0.1390
1.148
5739/361
0.0359
0.0653
1.046
Ra [I > 2
r(I)]
wR2a (all data)
Goodness-of-fit (GOF)b
P
P
2
2
1=2
|Fo|, wR2 ¼ f ½wðF2o ꢀ Fc2Þ ꢂ= ½wðF2oÞ ꢂg
.
a
R =
R
||Fo| ꢀ |Fc||/
R
P
GOF ¼ f ½wðF2o ꢀ F2c Þ ꢂ=ðn ꢀ pÞg1=2, where n is the number of data and p is the number of parameters refined.
2
b
OMe
OMe
PPh2
PPh2
o
3,5-OMe 1
2,5-OMe 2
2,4-OMe 3
3,4-OMe 4
2 Et3N, 0 C
NH2 + 2PPh2Cl
N
- 2 Et3NHCl
MeO
MeO
excess E
thf
OMe
E
1a-4a
1b-4b
E = O
E = S
PPh2
N
E = Se 1c-4c
PPh2
MeO
E
Scheme 1. Synthesis of bis(phosphino)amines 1–4 and their oxides 1a–4a, sulfides 1b–4b and selenides 1c–4c.
by analytical and spectroscopic methods, and furthermore, in the
case of 1c and 2b, by X-ray crystallography. The 31P NMR spectra
of the oxides 1a–4a display singlets at d 22.0, 26.1, 25.1 and
29.5 ppm, the sulfides 1b–4b at d 68.4, 67.5, 67.9 and 73.6 ppm,
and the selenides 1c–4c at d 69.1, 65.2, 65.9 and 69.8 ppm, respec-
tively. The 31P NMR resonances of these chalcogenes are consis-
tent with similar compounds [14]. During the oxidation reaction
of 1–4 with elemental sulfur and selenium, stepwise oxidation is
observed, typical of bis(phosphorus) compounds with (bulky) di-
phenyl substituents [24]. In the case of the selenides satellites
with 1JP–Se of about 800 Hz are observed, slightly larger than those
observed with alkyl substituents (772–776 Hz) [25]. The IR spectra
contain absorptions at 800–900 cmꢀ1 corresponding to the P–N–P
bonds. The P@O bonds in 1a–4a exhibits vibrations around
1200 cmꢀ1, and bands between 654 and 725 cmꢀ1 that are charac-
teristic of the P@S bonds are observed in 1b–4b and vibrations be-
tween 554 and 571 cmꢀ1 ascribed to P@Se bonds are observed in
1c–4c.
Single-crystals of 1c and 2b were obtained by slow diffusion of
diethyl ether into a solution of 1c or 2b in dichloromethane. The
crystallographic data of 1c and 2b are listed in Table 1, and their
structures are illustrated in Figs. 1 and 2. Key bond lengths and an-
gles (provided in the figure captions) are in keeping with structur-
ally similar compounds. The P–N distances in the selenium
compound 1c [1.727(2) and 1.722(2) Å] are slightly longer than
those in the sulfur compound 2b [1.713(14) and 1.707(15) Å] and
the P(1)–N(1)–P(1) angle in 1c is slightly larger than that in 2b
[125.97(12) and 124.50(8)°, respectively].
In order to probe the ability of 1–4 to act as ligands they were
reacted with several transition metal precursors (Scheme 2). Reaction
of 1–4 with equimolar quantities of [MCl2(cod)] (M = Pt or Pd; cod =
cycloocta-1,5-diene) in CH2Cl2 afforded the platinum(II)chloride

1044
N. Biricik et al. / Inorganica Chimica Acta 363 (2010) 1039–1047
Fig. 2. Molecular structure of 2b in the solid state. Key bond lengths (Å) and angles
(°): S(1)–P(1) 1.9402(6), S(2)–P(2) 1.9370(6), P(1)–N(1) 1.7134(14), P(1)–C(1)
1.8142(18), P(1)–C(7) 1.821(2), P(2)–N(1) 1.7079(15), N(1)–P(1)–S(1) 115.03(5),
N(1)–P(2)–S(2) 113.54(5), P(2)–N(1)–P(1) 124.50(8).
to give
a compounds that exhibits a singlet resonance at
59.8 ppm in the 31P NMR spectrum. Further spectroscopic and ana-
lytical data confirms the anticipated structures and is provided in
Section 2.
Fig. 1. Molecular structure of 1c in the solid state. Key bond lengths (Å) and angles
(°): Se(1)–P(1) 2.1092(8), Se(2)–P(2) 2.1125(8), P(1)–N(1) 1.727(2), P(1)–C(7)
1.824(3), P(1)–C(1) 1.829(3), P(2)–N(1) 1.722(2), N(1)–P(1)–Se(1), 115.59(8),
N(1)–P(2)–Se(2), 115.11(8), P(2)–N(1)–P(1), 125.97(12).
Single crystals of 1d, 1e, 3d, 3e and 4e obtained by slow diffusion
of diethyl ether into solutions of the complexes in dichloromethane
were analysed by single crystal X-ray diffraction and the details of
the structure determinations are given in Table 1. Molecular struc-
tures of 1d, 1e, 3d, 3e and 4e are shown in Figs. 3–7, respectively,
with key bond lengths and angles listed in the captions.
There are close similarities around the 4-membered P–N–P–Pd
ring in 1c, 2b, 1d, 1e, 3d, 3e, 4e, with the bond distances and angles
falling within narrow ranges. In the platinum complexes 1d and 3d,
the P–Pt–P angles are 72.59(3) and 72.54(8)° and the and P–N–P an-
gles are 98.7(3) and 99.63(12)°, respectively. The differences of the
positions the methoxyl substituents have little influence on the
geometry at the metal center. The P–Pd–P angles in 1e, 3e and 3e
[71.99(5), 72.20(6) and 72.55(5)°] are also very close and match
the values observed in 1d and 3d, despite the smaller size of the pal-
ladium ion compared to that of the platinum ion with the P–N–P an-
gles in 1e, 3e and 3e being 99.4(4) and 98.8(3) and 99.32 (16)°,
respectively.
complexes 1d–4d and the palladium(II)chloride complexes 1e–4e
in good yield. The 31P NMR spectra of 1d–4d and 1e–4e display
singlet resonances in the ranges 20.0–25.3 and 34.1–38.2 ppm,
1
respectively, with the platinum complexes showing JP–Pt
couplings of around 3400 Hz consistent with the cis-geometry.
Reaction of 1–4 with [Cu(CH3CN)4]PF6 in 2:1 ratio in CH2Cl2 gave
the cationic copper complexes [Cu{Ph2P)2N-C6H3-R}2]PF6 (1f–4f,
Scheme 2). The 31P NMR spectra of 1f–4f also display singlet
resonances that are observed in the range 87.6–89.0 ppm together
ꢀ
with a septet at ca. ꢀ144.4 ppm for the PF6 counter anion. Again,
the 31P NMR signals of the complexes are in keeping with structur-
ally related compounds [3,9–11,22]. Complex 4f is highly unstable
and could not be isolated as a pure product, rapidly decomposing
OMe
PPh2
N
1-4
PPh2
MeO
MCl2(cod)
[Cu(CH3CN)4]PF6
OMe
Ph2
P
OMe
OMe
Ph2
P
Ph2
P
PF6
N
P
N
Cu
N
MCl2
P
OMe
P
MeO
MeO
Ph2 Ph2
Ph2
M = Pt 1d-4d, M = Pd 1e-4e
1f-4f
Scheme 2. Reactions of the bis(phosphino)amines 1–4 with [MCl2(cod)] (M = Pt, Pd) and [Cu(CH3CN)4]PF6.

N. Biricik et al. / Inorganica Chimica Acta 363 (2010) 1039–1047
1045
Fig. 5. Molecular structure of 3d in the solid state. Key bond lengths (Å) and angles
(°): Pt(1)–P(1) 2.2014(15), Pt(1)–P(1)#1 2.2015(15), Pt(1)–Cl(1)#1 2.3595(15),
Pt(1)–Cl(1) 2.3595(15), P(1)–N(1) 1.717(4), P(1)–P(1)#1 2.605(3), N(1)–P(1)#1
1.717(4), P(1)–Pt(1)–P(1)#1 72.54(8), P(1)–Pt(1)–Cl(1)#1 170.10(5), P(1)#1–Pt(1)–
Cl(1)#1 97.59(5), P(1)–Pt(1)–Cl(1) 97.59(5), P(1)#1–Pt(1)–Cl(1) 170.09(5), Cl(1)#1–
Pt(1)–Cl(1) 92.26(8), P(1)#1–N(1)–P(1) 98.7(3).
Fig. 3. Molecular structure of 1d in the solid state. Key bond lengths (Å) and angles
(°): Pt(1)–P(2) 2.1942(8), Pt(1)–P(1) 2.2111(7), Pt(1)–Cl(1) 2.3634(8), Pt(1)–Cl(2)
2.3681(7), P(1)–N(1) 1.706(2), P(1)–P(2) 2.6077(10), P(2)–N(1) 1.708(2), P(2)–
Pt(1)–P(1) 72.59(3), P(2)–Pt(1)–Cl(1) 172.93(3), P(1)–Pt(1)–Cl(1) 100.57(3), P(2)–
Pt(1)–Cl(2) 94.95(3), P(1)–Pt(1)–Cl(2) 167.50(3), Cl(1)–Pt(1)–Cl(2) 91.91(3), P(1)–
N(1)–P(2) 99.63(12), P(2)–Pd(1)–P(1) 71.99(5), P(2)–Pd(1)–Cl(1) 171.65(5), P(1)–
Pd(1)–Cl(1) 99.85(5), P(2)–Pd(1)–Cl(2) 92.72(5), P(1)–Pd(1)–Cl(2) 164.68(5), Cl(1)–
Pd(1)–Cl(2) 95.46(5), P(2)–N(1)–P(1) 99.4(2).
Fig. 6. Molecular structure of 3e in the solid state. Key bond lengths (Å) and angles
(°): Pd(1)–P(1)#1 2.2154(11), Pd(1)–P(1) 2.2155(11), Pd(1)–Cl(1)#1 2.3607(11),
Pd(1)–Cl(1) 2.3607(11), P(1)–N(1) 1.719(4), P(1)–P(1)#1 2.611(2), N(1)–P(1)#1
1.719(4), P(1)#1–Pd(1)–P(1) 72.20(6), P(1)#1–Pd(1)–Cl(1)#1 96.20(4), P(1)–Pd(1)–
Cl(1)#1 168.41(4), P(1)#1–Pd(1)–Cl(1) 168.41(4), P(1)–Pd(1)–Cl(1) 96.21(4),
Cl(1)#1–Pd(1)–Cl(1) 95.39(6), P(1)–N(1)–P(1)#1 98.8(3).
Fig. 4. Molecular structure of 1e in the solid state. Key bond lengths (Å) and angles
(°): Pd(1)–P(2) 2.2070(15), Pd(1)–P(1) 2.2358(15), Pd(1)–Cl(1) 2.3757(14), Pd(1)–
Cl(2) 2.3776(14), P(1)–N(1) 1.716(4), P(1)–P(2) 2.611(2), P(2)–N(1) 1.709(4), P(2)–
Pd(1)–P(1) 71.99(5), P(2)–Pd(1)–Cl(1) 171.65(5), P(1)–Pd(1)–Cl(1) 99.85(5), P(2)–
Pd(1)–Cl(2) 92.72(5), P(1)–Pd(1)–Cl(2) 164.68(5), Cl(1)–Pd(1)–Cl(2) 95.46(5), P(2)–
N(1)–P(1) 99.4(2).
parameters such as solvent, base, catalyst loading and tempera-
ture. Following reaction optimization we found that use of 1% of
the Pd pre-catalysts (1e–4e) with 2 equiv. of K2CO3 in dioxane at
80 °C led to the good conversions within 6 h. The activity of 1e–
4e to catalyze the coupling of 4-bromoacetophenone with styrene
(Table 2, entries 2 and 7) was initially evaluated (a control exper-
iment indicated that the coupling reaction did not occur in the ab-
sence of 1e–4e).
3.1. Heck reactions
Under the reaction conditions, a wide range of aryl bromides
bearing electron-donating or electron-withdrawing groups reacted
with styrene, affording the coupled products in excellent yields.
The Heck reaction is widely used to prepare disubstituted ole-
fins [26]. The rate of the coupling is dependent on a variety of

1046
N. Biricik et al. / Inorganica Chimica Acta 363 (2010) 1039–1047
Table 3
Suzuki coupling reactions of aryl bromides with phenylboronic acid.
Pd complex (1 %)
R
+
Br
R
B(OH)2
Dioxan, 80°C
Cs2CO3 (2 equiv.)
Entry
R
Cat.
Yielda (%)
1
2
3
4
5
6
7
8
COCH3
COCH3
COCH3
COCH3
COCH3
COCH3
COCH3
CHO
CHO
CHO
CHO
OCH3
OCH3
OCH3
H
1e
2e
3e
4e
4e
4e
4e
1e
2e
3e
4e
1e
3e
4e
1e
2e
3e
4e
95
91
97
78b
61c
52d
92
88
79
84
78
89
87
89
93
90
94
95
9
10
11
12
13
14
15
16
17
18
H
H
H
Fig. 7. Molecular structure of 4e in the solid state. Key bond lengths (Å) and angles
(°): Pd(1)–P(1) 2.2065(10), Pd(1)–P(2) 2.2069(11), Pd(1)–Cl(1) 2.3527(11), Pd(1)–
Cl(2) 2.3568(10), P(1)–N(1) 1.720(3), P(1)–P(2) 2.6113(16), P(2)–N(1) 1.706(3),
P(1)–Pd(1)–P(2) 72.55(5), P(1)–Pd(1)–Cl(1) 94.67(5), P(2)–Pd(1)–Cl(1) 167.08(5),
P(1)–Pd(1)–Cl(2) 168.49(4), P(2)–Pd(1)–Cl(2) 96.29(4), Cl(1)–Pd(1)–Cl(2) 96.57(4),
P(2)–N(1)–P(1) 99.32(16).
a
Reaction conditions: 1.0 mmol of R-C6H4Br-p, 1.5 mmol of phenylboronic acid,
2 mmol Cs2CO3, 1% Pd complex, dioxane (3 mL), 80 °C, 2 h. Purity of compounds was
checked by 1H NMR and yields are based on aryl bromide. All reactions were
monitored by GC.
b
K2CO3.
c
KOBut.
For substrates with electron donor groups, the palladium com-
plexes are less active (Table 2, entries 16–23). It is interesting to
note that 4e is usually the most active pre-catalyst, especially for
d
50 °C.
substrates with electron-withdrawing substitute, while all the
complexes exhibit similar activities if substrates with electron-
donation groups are employed. For activated substrates bearing
electron-withdrawing groups, the catalytic activities of the palla-
dium complexes 1e–4e with ether-functionalized aminophos-
phines are comparable with those of ether-groups. However, for
non-activated substrates the palladium complexes 1e–4e show in-
creased catalytic activities [27].
Table 2
Heck coupling reactions of aryl bromides with styrene.
R
Pd complex (1 %)
Br
R
+
Dioxan, 80°C
K2CO3 (2 equiv.)
Entry
R
Cat.
Yielda (%)
3.2. Suzuki reactions
1
2
3
COCH3
COCH3
COCH3
COCH3
COCH3
COCH3
COCH3
CHO
CHO
CHO
CHO
H
H
H
H
OCH3
OCH3
OCH3
OCH3
CH3
1e
2e
3e
4e
4e
4e
4e
1e
2e
3e
4e
1e
2e
3e
4e
1e
2e
3e
4e
1e
2e
3e
4e
65
71
68
81
56
49
85
76
72
58
84
30
38
66
70
65
68
69
64
37
47
78
66
Palladium-catalysed Suzuki coupling reactions are now the
method of choice for the synthesis of biaryl and heterobiaryl com-
pounds, [28] present in numerous classes of organic compounds,
such as natural products, pharmaceuticals, agrochemicals and
functional materials such as liquid crystals [29]. The reaction gen-
erally results in excellent yields when performed at temperatures
of 80–100 °C with aryl halides. Here, the amiophpsphine com-
plexes 1e–4e were performed in dioxane with Cs2CO3 as the base
at 80 °C following reaction optimization (Table 3).
All complexes are effective pre-catalysts for the coupling of
unactivated, activated and deactivated arylbromides. There does
not appear to be a general trend related to the positions of the
methoxyl groups in the ligands (although complex 2e gave slightly
lower yield (1–3%) compared to complexes 1e, 3e and 4e). The nat-
ure of the base used strongly influences the yield of the desired
products with stronger bases resulting in lower yields (Table 3, en-
tries 4–7).
4b
5c
6d
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
CH3
CH3
CH3
a
Reaction conditions: 1.0 mmol of R-C6H4Br-p, 1.5 mmol of styrene, 2 mmol
K2CO3, 1% Pd complex, dioxane (3 mL), 80 °C, 6 h. Purity of compounds was checked
4. Conclusions
by 1H NMR and yields are based on aryl bromide. All reactions were monitored by
GC.
b
In conclusion, a series of new bis(phosphino)amines and their
oxides, sulfides, selenides, and transition metal complexes have
been prepared. The ligands exhibit similar reactivities towards
Cs2CO3.
c
KOBut.
d
50 °C.

N. Biricik et al. / Inorganica Chimica Acta 363 (2010) 1039–1047
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1047
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for financial support.
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