Synthesis and characterizations of N,N,N′,N′-tetrakis (diphenylphosphino)ethylendiamine derivatives: Use of palladium(II) complex as pre-catalyst in Suzuki coupling and Heck reactions

Article abstract of DOI:10.1016/j.jorganchem.2008.11.063

Oxidation of N,N,N′,N′-tetrakis(diphenylphosphino)ethylendiamine (1) with elemental sulfur and selenium gives the corresponding sulfide and selenide, respectively, [(Ph₂P(E))₂NCH₂CH₂N(P(E)Ph ₂)₂] (E: S 1a, Se 1b). Complexes of 1 [(M₂Cl₄){(Ph₂P)₂NCH ₂CH₂N(PPh₂)₂}] (M: Ni(II) 1c, Pd(II) 1d, Pt(II) 1e) were prepared by the reaction of 1 with NiCl₂ or [MCl₂(COD)] (M = Pd, Pt). The new compounds were characterized by NMR, IR spectroscopy and elemental analysis. The catalytic activity of Pd(II) complex 1d was tested in the Suzuki coupling reaction and Heck reaction. The palladium complex 1d catalyses the Heck reaction between styrene and aryl bromides as well as Suzuki coupling reaction between phenylboronic acid and arylbromides affording stilbenes and biphenyls in high yield, respectively.

Full text of DOI:10.1016/j.jorganchem.2008.11.063

Journal of Organometallic Chemistry 694 (2009) 731–736
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis and characterizations of N,N,N0,N0-tetrakis
(diphenylphosphino)ethylendiamine derivatives: Use of palladium(II) complex
as pre-catalyst in Suzuki coupling and Heck reactions
a
a
a
a
b
Osman Akba a, , Feyyaz Durap , Murat Aydemir , Akın Baysal , Bahattin Gümgüm , Saim Özkar
*
a Department of Chemistry, University of Dicle, 21280 Diyarbakir, Turkey
b Department of Chemistry, Middle East Technical University, 06531 Ankara, Turkey
a r t i c l e i n f o
a b s t r a c t
Oxidation of N,N,N0,N0-tetrakis(diphenylphosphino)ethylendiamine (1) with elemental sulfur and sele-
nium gives the corresponding sulfide and selenide, respectively, [(Ph2P(E))2NCH2CH2N(P(E)Ph2)2] (E: S
1a, Se 1b). Complexes of 1 [(M2Cl4){(Ph2P)2NCH2CH2N(PPh2)2}] (M: Ni(II) 1c, Pd(II) 1d, Pt(II) 1e) were pre-
pared by the reaction of 1 with NiCl2 or [MCl2(COD)] (M = Pd, Pt). The new compounds were character-
ized by NMR, IR spectroscopy and elemental analysis. The catalytic activity of Pd(II) complex 1d was
tested in the Suzuki coupling reaction and Heck reaction. The palladium complex 1d catalyses the Heck
reaction between styrene and aryl bromides as well as Suzuki coupling reaction between phenylboronic
acid and arylbromides affording stilbenes and biphenyls in high yield, respectively.
Article history:
Received 15 October 2008
Received in revised form 25 November 2008
Accepted 28 November 2008
Available online 7 December 2008
Keywords:
Aminophosphine
Suzuki coupling
Heck reaction
Catalysis
Ó 2008 Elsevier B.V. All rights reserved.
Palladium
Platinum
1. Introduction
widespread applications in synthetic organic chemistry and mate-
rials science [48,49].
There is enormous interest in the chemistry of bis(phos-
phino)amines bearing P–N–P backbone due to their wide range
of applications in coordination chemistry [1–5]. Small variations
in the electron density on the donor atoms of these ligands can
cause significant changes in their coordination behaviors and
structural features of resulting complexes [6–10]. Potentially this
ligand family is extremely attractive since their various structural
modifications are accessible via simple P–N bond formation. The
improved catalytic activity of transition metal complexes with
hemilabile ligands has been extensively reviewed [11–14]. There
has been recently increasing interest in the synthesis of highly ac-
tive transition metal based catalysts derived from aminophos-
phines that can be used in different catalytic reactions including
allylic alkylation [15–18], ammination [19–21], Heck [22–30],
Suzuki [31–35], hydroformylation [36–39] and hydrogenation
reactions [40–44]. Palladium containing catalysts serve as straight-
forward and extremely powerful reagents for the carbon–carbon
bond formation [45–47]. Among palladium-catalyzed coupling
processes, reaction of aryl halides with olefins (the Heck reaction)
and with boronic acid (the Suzuki coupling reaction) are emerging
as a favorite methods for the C–C bond formation and have found
Herein, we report the synthesis of chalcogenides (sulfide and
selenide) as well as the (Ni2+, Pd2+ and Pt2+) complexes of
N,N,N0,N0-tetrakis(diphenylphosphino)ethylendiamine 1. We also
report on the catalytic activity of palladium(II) complex of 1 as
pre-catalysts in the Suzuki coupling reactions and Heck reactions.
The compounds were fully characterized by elemental analysis,
IR, 1H NMR, 31P–{1H} NMR spectroscopy.
2. Results and discussion
N,N,N0,N0-Tetrakis(diphenylphosphino)ethylendiamine, [(Ph2-
P)2NCH2CH2N(PPh2)2] (1) was prepared from the reaction of
H2N–CH2CH2–NH2 and 4 equiv. Ph2PCl in thf at ꢀ10 °C (Scheme
1) and identified by NMR spectral data as reported elsewhere [50].
Oxidation of 1 with elemental sulfur and selenium gave the cor-
responding sulfide 1a and selenium 1b, respectively (Scheme 2).
Oxidation with sulfur or selenium had to be carried out at elevated
temperatures, as expected because elemental sulfur and selenium
are weaker oxidizing agents than hydrogen peroxide, especially to-
wards the phosphorus atoms with bulky phenyl groups [51–54].
N,N,N0,N0-tetrakis(diphenyloxophosphino)ethylendiamine have al-
ready been reported in our previous paper [50].
The oxidation reactions were followed by monitoring the
* Corresponding author. Tel.: +90 412 2488550x3175; fax: +90 412 2488300.
E-mail address: oakba@dicle.edu.tr (O. Akba).
changes in 31P–{1H} NMR signal. The 31P NMR spectrum of 1 shows
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.11.063

732
O. Akba et al. / Journal of Organometallic Chemistry 694 (2009) 731–736
thf -10oC
+
4PPh2Cl
Ph P
2
N
N
PPh
2
+
4Et3NHCl
Et3N
H N
2
NH
2
PPh
PPh
2
2
1
Scheme 1. Aminolysis reaction of ethylendiamine with Ph2PCl in thf.
thf
+
4E
Ph2P
N
N
PPh2
Ph2P
E
N
N
PPh2
reflux, 6 h
E
Ph2P
Ph2P
PPh2
Ph2P
E
E
E: S 1a, Se 1b
1
Scheme 2. Oxidation reaction of 1 with elemental sulfur and selenium.
a singlet resonance at d = 61.3 ppm. Oxidation of 1 with elemental
sulfur and selenium in thf gave the corresponding sulfide and sel-
enide, respectively: (Ph2P(E))2NCH2CH2N(P(E)Ph2)2 (E: S 1a, Se 1b).
In 31P–{1H} NMR spectrum, 1a shows a singlet at d = 69.6 ppm
while 1b exhibits a singlet at d = 72.3 ppm, accompanied with sele-
nium satellites (J(31P–77Se): 784 Hz).
3. The Suzuki coupling reactions
Palladium-catalysed coupling via Suzuki reaction has become,
over the last ten years, the method of choice for biaryl and hetero-
biaryl synthesis [57,58]. These moieties are widely present in
numerous classes of organic compounds, such as natural product,
pharmaceuticals, agrochemicals and ligands for asymmetric syn-
thesis and in new materials, such as liquid crystals [59]. The reac-
tion generally results in excellent yields when performed at
temperatures of 80–100 °C with aryl iodides and bromides. Re-
cently, the Suzuki reaction of aryl chlorides catalysed by palla-
dium-tertiary phosphine [60] systems has been studied
extensively due to economically attractive nature of the starting
materials.
In order to survey the reaction parameters for the catalytic Su-
zuki reaction, we examined Cs2CO3, K2CO3 and KtOBu as base and
DMF and dioxane as solvent. We found that the reaction performed
in dioxane, with Cs2CO3 as the base at 80 °C appeared to provide
the best results. We initially tested the catalytic activity of the
complex 1d for the coupling of p-bromoacetophenone with phen-
ylboronic acid and the control experiments showed that the cou-
pling reaction did not occur in the absence of the catalyst. Under
these conditions, p-bromoacetophenone, p-bromobenzaldehyde,
p-bromobenzene, p-bromoanisole and p-bromotoluene react with
phenylboronic acid in good yields (Table 1).
The reactions of 1 with 2 equiv. of anhydrous NiCl2 in the mixed
solvents of CH2Cl2–methanol (1:1 in volume) at room temperature
led to the formation of the corresponding dinuclear nickel(II) diph-
osphinoamine complex 1c in high yield (Scheme 3). The 31P–{1H}
NMR spectrum of 1c exhibits only a singlet at 54.1 ppm which is
within the range expected for structurally similar complexes [55].
In the reaction of 1 with 2 equiv. [M(cod)Cl2] (M = Pd, Pt;
cod = 1,5-cyclooctadiene) in thf solution, cod is replaced by
(Ph2P)2NCH2CH2N(PPh2)2 coordinating to each of two metal cen-
ters as bidentate ligand and yielding the respective [Cl2M–
(Ph2P)2NCH2CH2N(PPh2)2ꢀMCl2] complexes 1d, 1e (M = Pd, Pt,
respectively) (Scheme 4).
The palladium complex 1d shows a singlet at 35.9 in the 31P–
{1H} NMR spectrum which is shifted upfield (
D
d: ꢀ25.9 ppm)
compared to the free ligand 1 (61.3 ppm) [50]. The 31P–{1H} NMR
spectrum of the 1e exhibits a signal at 16.5 ppm accompanied by
the 195Pt satellite (J(195Pt–31P) = 3392 Hz) which is also shifted up-
field (
D
d: ꢀ44.4 ppm) compared to the free ligand 1 (61.3 ppm).
The large 1J(135Pt–31P) coupling constant of 3392 Hz for 1e is indic-
ative of a cis arrangement of phosphines around a platinum(II)
centre [56]. The 31P–{1H} NMR chemical shifts of complexes 1d
and 1e are within the range expected for structurally similar
complexes having P–N–P bond.
4. The Heck coupling reactions
All the three complexes 1c, 1d, 1e could be isolated as analyti-
cally pure solid material and characterized by elemental analysis,
IR, 1H NMR and 31P–{1H} NMR spectroscopy. Their 13C NMR spectra
could not be attained due to the low solubility of the complexes in
all common solvents.
Heck reactions, typically catalysed by palladium complexes in
solution, are of growing interest in organic and fine-chemical syn-
thesis [61]. In the last thirty years, the Heck reactions has been
extensively explored and used in several diverse areas such as
the preparation of hydrocarbons, novel polymers, pharmaceuticals,
CH2Cl2-MeOH
2NiCl2
Ph P
2
N
N
PPh
2
+
Ph P
2
N
N
PPh
2
rt, 1h
PPh
PPh
Cl
Ni
Cl
PPh
Ph P
2
Ni
Cl
Cl
2
2
2
1
1c
Scheme 3. The reactions of 1 with 2 equiv. anhydrous NiCl2.

O. Akba et al. / Journal of Organometallic Chemistry 694 (2009) 731–736
733
CH Cl
2
2
2 M(COD)Cl
Ph P
2
N
N
PPh
+
2
2
Ph P
2
N
N
PPh
M
2
rt, 1h
PPh
PPh
Cl
M
PPh
Ph P
2
Cl
2
2
2
Cl
Cl
M: Pd 1d, Pt 1e
1
Scheme 4. The reactions of 1 with 2 equiv. M(COD)Cl2.
Table 1
The Suzuki coupling reactions of aryl bromides with phenylboronic acid.
0.01 mmol 1d (Cat)
B(OH)
Br
R
R
2
o
Dioxane, 80 C, 1 h
Cs CO (2 equiv.)
2
3
Entry
R
Conversion (%)
Yield (%)
1
2
3
4
5
COCH3
CHO
H
OCH3
CH3
98.3
99.4
92.3
54.6
59.6
97.6
98.8
90.8
53.8
57.2
Reaction conditions: 1.0 mmol of p-R-C6H4Br aryl bromide, 1.5 mmol of phenylboronic acid, 2.0 mmol Cs2CO3, 0.01 mmol 1d (Cat.), dioxane 3.0 (mL). Purity of compounds was
checked by NMR and yields are based on arylbromide. All reactions were monitored by GC; 80 °C, 1 h.
agrochemicals, dyes and new enantioselective syntheses of natural
products, because of the mild conditions required for the reaction
[62–66]. The Heck reaction [67,68] has been shown to be very use-
ful for the preparation of disubstituted olefins. The rate of coupling
is dependent on a variety of parameters such as temperature, sol-
vent, base and catalyst loading. Generally, the Heck reactions con-
ducted with tertiary phosphine complexes require high
temperatures (higher than 120 °C) and polar solvents. For the
choice of base, we surveyed Cs2CO3, K2CO3 and KtOBu. Finally, we
found that use of 1.0 mol% 1d and 2 equiv. K2CO3 in DMF at
110 °C led to the highest conversion within 1 h. We initially tested
the catalytic activity of 1d for the coupling of 4-bromoacetophe-
none with styrene.
electron-deficient bromides were beneficial for the conversions
(Table 2).
Only the palladium complex 1d was found to be catalytically
active in Suzuki coupling and Heck reactions, while nickel and plat-
inum complexes 1c and 1e exhibited no catalytic activities in line
with the previous observations [69]. This might be attributed to
the different metal-ligand bond strengths in palladium complexes
from those in nickel and platinum complexes. Depending on the
type of coupling reaction, high yields of the desired products were
obtained but using 1d as catalyst. The palladium complex 1d ap-
pears to be a more efficient catalyst for the Heck reactions of aryl
bromides than that of aryl chlorides (yields 0.5–20%).
The complex 1d exhibits relatively higher activity in both Suzu-
ki and Heck reactions of aryl bromides with electron-withdrawing
substituents than that with electron-releasing substituent on the
aryl bromides in both reactions. It is generally believed that elec-
tron-withdrawing groups (R = EWG) on the aryl or alkenyl moiety
will enhance the oxidative addition rate by weakening the Ar–X
A control experiment indicated that the coupling reaction did
not occur in the absence of 1d. Under the predetermined reaction
conditions, a wide range of aryl bromides bearing electron-
releasing and electron-withdrawing groups reacted with styrene,
affording the coupled products in excellent yields. As expected,
Table 2
The Heck coupling reactions of aryl bromides with styrene.
0.01 mmol 1d (Cat)
+
Br
R
o
DMF, 110 C, 1.0 h
R
K CO (2 equiv.)
2
3
Entry
R
Conversion (%)
Yield (%)
1
2
3
4
5
COCH3
CHO
H
OCH3
CH3
96.6
95.7
63.6
54.7
56.9
92.1
93.4
59.2
48.1
53.8
Reaction conditions: 1.0 mmol of p-R-C6H4Br aryl bromide, 1.5 mmol of styrene, 2.0 mmol K2CO3, 0.01 mmol% Pd (Cat.), DMF 3.0 (mL). Purity of compounds was checked by
NMR and yields are based on arylbromide. All reactions were monitored by GC; 110 °C, 1.0 h.

734
O. Akba et al. / Journal of Organometallic Chemistry 694 (2009) 731–736
bond [70–72]. 31P–{1H} NMR spectroscopy suggests that in the
both catalytic reactions aminophosphine ligand decomposes to
PPh2(O)H as indicated by signal at d = 20 ppm [73–75].
131.31 (s, p-carbons of phenyls), 132.33(s, i-carbons of phenyls),
133.27 (d, J(31P–13C): 12 Hz, m-carbons of phenyls), assignment
31
was based on the 1H–13C HETCOR spectrum. P–{1H} NMR (ppm
rel. to H3PO4 in CDCl3) d: 73.1. Selected IR (cmꢀ1 from KBr pellet):
mN-P-N: 881, mP-S: 650.
5. Conclusion
6.2. Synthesis of N,N,N0,N0-
tetrakis(diphenylselenophosphino)ethylendiamine
[(Ph2P(Se))2NCH2CH2N(P(Se)Ph2)2] (1b)
The dinuclear nickel, palladium and platinum complexes as
well as the sulfide and selenide chalcogenides of N,N,N0,N0-
tetrakis(diphenylphosphino)ethylendiamine were prepared and
characterized. Because of the strength of the Pt–C bonds, Pt(II)-
bis(phosphino)amine 1e system exhibited no catalytic activity
[76]. Only the palladium complex was found to show catalytic
activity in both the Suzuki coupling and Heck reactions of aryl bro-
mides. In both cases, the catalytic activity of complex 1d was found
to be higher in reactions of aryl bromides with electron-withdraw-
ing substituent than that with electron-releasing substituent. The
catalytic activity and the yield of coupling reactions could be con-
trolled over a wide range by variation of the coupling parameters.
To a solution of N,N,N0,N0-tetrakis(diphenylphosphino)ethylen-
diamine (50 mg, 0.0628 mmol) in thf (20 mL), grey Se (19.8 mg,
0.251 mmol) was added and this mixture was refluxed for 6 h.
The volume of the reaction solution was reduced to ca. 1–2 mL
by evaporating the volatiles in vacuum. Addition of n-hexane
(20 mL) to this solution gave 1b as white solid which was collected
by suction filtration. (Ph2P(Se))2NCH2CH2N(P(Se)Ph2)2 38 mg (55%
yield); m.p. 156–158 °C. Anal., Calc. for C50H44N2P4Se4: C, 53.98; H,
3.99; N, 2.52. Found: C, 53.37; H, 3.78; N, 2.28%. 1H NMR (ppm rel.
to TMS in CDCl3) d: 3.73 (s, 4H, N-CH2-), 7.20 (m, 16H, o-hydrogens
of phenyls), 7.32 (m, 8H, p-hydrogens of phenyls) and 7.73 (m,
16H, m-hydrogens of phenyls). 13C NMR (ppm in CDCl3) d: 50.62
(N-CH2-), 127.75 (d, J(31P–13C): 13 Hz, o-carbons of phenyls),
131.45 (s, p-carbons of phenyls), 132.49 (s, i-carbons of phenyls),
133.88 (d, J(31P–13C): 11 Hz, m-carbons of phenyls), assignment
was based on the 1H–13C HETCOR spectrum. 31P–{1H} NMR (ppm
rel. to H3PO4 in CDCl3) d: 72.3, (1J(31P–77Se): 784 Hz). Selected IR
6. Experimental
All reactions and manipulations were performed under argon
atmosphere unless otherwise stated. Ph2PCl, ethylendiamine were
purchased from Fluka and anhydrous nickel, palladium and plati-
num salts were purchased from Aldrich and used as received. Ana-
lytical grade and deuterated solvents were purchased from Merck.
Solvents were dried using the appropriate reagents and distilled
prior to use. Infrared spectra were recorded from KBr pellet in
the range 4000–400 cmꢀ1 on a Mattson 1000 ATI UNICAM FT-IR
spectrometer. NMR spectra were taken on Bruker AC 400 spec-
trometer (400.1 MHz for 1H, 100.6 MHz for 13C, and 162.0 MHz
for 31P). Chemical shifts were referenced to the internal TMS for
1H and 13C, and to the signal of external 85% H3PO4 in capillary
for 31P. GC analyses were performed on a HP 6890N Gas Chromato-
graph equipped with a capillary column (5% diphenyl, 95% dimeth-
(cmꢀ1 from KBr pellet):
mN-P-N: 887, mP-Se: 567.
6.3. Synthesis of
l
-N,N,N0,N0-
Tetrakis(diphenylphosphino)ethylendiamine bis(dichloronickel(II))
(1c)
A solution of (Ph2P)2NCH2CH2N(PPh2)2 1 (100 mg, 0.125 mmol)
in CH2Cl2 (10 mL) was added to the solution of anhydrous NiCl2
(33 mg, 0.25 mmol) in CH3OH (10 mL). Upon stirring for 1 h at
room temperature, the mixture was turned to dark red. The vol-
ume of the solution was reduced by evaporation of volatiles in vac-
uum to ca. 1–2 mL and addition of n-hexane (20 mL) gave 1c as a
red solid which was collected by suction filtration and dried in vac-
uum. Cl2Ni-(Ph2P)2NCH2CH2N(PPh2)2-NiCl2 125 mg, (94% yield);
m.p. 223 °C (dec.) Anal., Calc. for C50H44N2P4Ni2Cl4: C, 56.87; H,
4.20; N, 2.65. Found: C, 56.57; H, 4.08; N, 2.48%. 1H NMR (ppm
rel. to TMS in CDCl3) d: 6.88–7.71 (m, 40H, phenyl hydrogens),
3.63 (s, 4H, N-CH2-). 13C NMR spectrum could not be taken due
to the low solubility of 1c in all common solvents. 31P–{1H} NMR
(ppm rel. to H3PO4 in CDCl3) d: 54.1 (s). Selected IR (cmꢀ1 from
ylsiloxane) (30 m ꢁ 0.32 mm ꢁ 0.25
lm). Elemental analysis was
carried out on a Fisons EA 1108 CHNS-O instrument. Melting
points were determined on a Gallenkamp Model apparatus with
open capillaries.
The starting materials [MCl2(COD)] (M = Pd, Pt, COD = 1,5-cyclo-
octadiene) were prepared according to literature procedures
[77,78]. N,N,N0,N0-tetrakis(diphenylphosphino)ethylendiamine
1
and N,N,N0,N0-tetrakis(diphenyloxophosphino)ethylendiamine were
prepared following the procedure given in the previous study
[50].
6.1. Synthesis of N,N,N0,N0-
KBr pellet):
m
N-P-N: 888.
tetrakis(diphenyltiyophosphino)ethylendiamine
[(Ph2P(S))2NCH2CH2N(P(S)Ph2)2] (1a)
6.4. Synthesis of
l
-N,N,N0,N0-
tetrakis(diphenylphosphino)ethylendiamine
bis(dichloropalladium(II)) (1d)
To a solution of N,N,N0,N0-tetrakis(diphenylphosphino)ethylen-
diamine 1 (50 mg, 0.0628 mmol) in thf (20 mL), S8 (8.0 mg,
0.251 mmol) was added and this mixture was refluxed for 6 h.
The hot solution was filtered through Celite to remove a small
amount of insoluble material. Volume of the filtrate solution was
reduced to ca. 1–2 mL by evaporating the volatiles in vacuum.
Addition of n-hexane (20 mL) to this solution gave 1a as
white solid which was collected by suction filtration. (Ph2P(S))2
NCH2CH2N(P(S)Ph2)2 (1a) 33 mg (57% yield); m.p. >250 °C
(dec.) Anal., Calc. for C50H44N2P4S4: C, 64.92; H, 4.80; N, 3.03.
Found: C, 64.61; H, 4.51; N, 2.93%. 1H NMR (ppm rel. to TMS in
CDCl3) d: 3.66 (s, 4H, N-CH2-), 7.21 (m, 16H, o-hydrogens of
phenyls), 7.34(m, 8H, p-hydrogens of phenyls) and 7.66(m, 16H,
m-hydrogens of phenyls). 13C NMR (ppm in CDCl3) d: 49.48
(N-CH2-), 127.74 (d, J(31P–13C): 14 Hz, o-carbons of phenyls),
A solution of Pd(COD)Cl2 (24 mg, 0.088 mmol) in CH2Cl2 (5 mL)
was added to the solution of (Ph2P)2NCH2CH2N(PPh2)2 1 (35 mg,
0.044 mmol) in CH2Cl2 (10 mL) and mixture was stirred for 1.5 h
at room temperature. Volume of the solution was reduced by
evaporation of volatiles in vacuum to ca. 1–2 mL and addition
of diethyl ether (20 mL) gave 1d as yellow solid which was
collected by suction filtration and dried in vacuum. Cl2Pd–
(Ph2P)2NCH2CH2N(PPh2)2–PdCl2 45 mg, (89% yield); m.p. 300 °C
(dec.). Anal., Calc. for C50H44N2P4Pd2Cl4: C, 52.16; H, 3.85; N,
2.43. Found: C, 51.94; H, 3.78; N, 2.38%. 1H NMR (ppm rel. to
TMS in DMSO-d6) d: 7.45–7.75 (m, 40H, phenyl hydrogens), 3.70
(s, 4H, N-CH2-). 13C NMR spectrum could not be taken due to the
low solubility of 1d in all common solvents. 31P–{1H} NMR (ppm

O. Akba et al. / Journal of Organometallic Chemistry 694 (2009) 731–736
735
rel. to H3PO4 in DMSO-d6) d: 35.9 (s). Selected IR (cmꢀ1 from KBr
pellet): N-P-N: 889.
[6] M.R.I. Zubiri, J.D. Woollins, Comment Inorgan. Chem. 24 (5–6) (2003) 189.
[7] N. Biricik, F. Durap, B. Gümgüm, Z. Fei, R. Scopelliti, Transition Met. Chem. 32
(2007) 877.
m
[8] F. Durap, N. Biricik, B. Gümgüm, S. Özkar, W.H. Ang, Z. Fei, R. Scopelliti,
Polyhedron 27 (2008) 196.
6.5. Synthesis of l
-N,N,N0,N0-
tetrakis(diphenylphosphino)ethylendiamine bis(dichloroplatinum(II))
(1e)
[9] T. Appleby, J.D. Woollins, Coord. Chem. Rev. 235 (2002) 121.
[10] Z. Fei, P.J. Dyson, Coord. Chem. Rev. 249 (2005) 2056.
[11] I. Bachert, P. Braunstein, R. Hasselbring, New J. Chem. 20 (1996) 993.
[12] I. Bachert, P. Braunstein, M.K. McCart, F. Fabrizi de Biani, F. Lashi, P. Zanello, G.
Kickelbick, U. Schubert, J. Organomet. Chem. 573 (1999) 47.
[13] I. Bachert, I. Bartussek, P. Braunstein, E. Guillon, J. Rose, G. Kickelbick, J.
Organomet. Chem. 580 (1999) 257.
A solution of Pt(COD)Cl2 (33 mg, 0.088 mmol) in CH2Cl2 (5 mL)
was added to the solution of (Ph2P)2NCH2CH2N(PPh2)2 1 (35 mg,
0.044 mmol) in CH2Cl2 (10 mL) and mixture was stirred for 1.5 h
at room temperature. Volume of the solution was reduced by
evaporation of volatiles in vacuum to ca. 1–2 mL and addition
of diethyl ether (20 mL) gave 1e as yellow solid which was
collected by suction filtration and dried in vacuum. Cl2Pt–
(Ph2P)2NCH2CH2N(PPh2)2–PtCl2 39 mg, (67% yield); m.p. 300 °C
(dec.). Anal., Calc. for C50H44N2P4Pt2Cl4: C, 45.20; H, 3.34; N, 2.11.
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Partial support from Turkish Academy of Sciences and Dicle
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