Ruthenium(II), copper(I) and silver(I) complexes of large bite bisphosphinite, bis(2-diphenylphosphinoxynaphthalen-1-yl)methane: Application of Ru(II) complexes towards the hydrogenation of styrene and phenylacetylene

Article abstract of DOI:10.1016/j.jorganchem.2006.06.040

Ruthenium(II), copper(I) and silver(I) complexes of large bite bisphosphinite Ph₂P{(-OC₁₀H₆)(μ-CH₂) (C₁₀H₆O-)}PPh₂ (1) are described. Reactions of bisphosphinite 1 with [Ru(η⁶-p-cymene)(μ-Cl)Cl]₂ and RuCl₂(PPh₃)₃ afford mono- and bis-chelate complexes [RuCl(η⁶-p-cymene){η²-Ph₂P{(-OC ₁₀H₆)(μ-CH₂)(C₁₀ H₆O-)}PPh₂-κP,κP}]Cl (2) and trans-[RuCl₂{η²-Ph₂P{ (-OC₁₀H₆)(μ-CH₂)(C₁₀ H₆O-)}PP h₂-κP,κP}₂] (3), respectively. Treatment of 1 with CuX (X = Cl, Br and I) furnish 10-membered chelate complexes of the type [Cu(X){η²-Ph₂P(-OC₁₀H₆)( μ-CH₂)(C₁₀H₆O-)PPh₂ -κP,κP}] (4, X = Cl; 5, X = Br; 6, X = I), whereas [Cu(MeCN)₄]PF₆ affords a bis-chelated cationic complex [Cu{η²-Ph₂P(-OC₁₀H₆) (μ-CH₂)(C₁₀H₆O-)PPh₂-κP ,κP}₂][PF₆] (7). Reaction between 1 and AgOTf produce both mono- and bis-chelated complexes [Ag{η²-Ph₂P(-OC₁₀H₆) (μ-CH₂)(C₁₀H₆O-)PPh₂-κP ,κP}(SO₃CF₃)] (8) and [Ag{η²-Ph₂P(-OC₁₀H₆) (μ-CH₂)(C₁₀H₆O-)PPh₂-κP ,κP}₂][SO₃CF₃] (9), respectively; whereas the similar reaction of 1 with[Ag(OTf)PPh₃] affords chelate complex of the type [Ag{η²-Ph₂P(-OC₁₀H₆) (μ-CH₂)(C₁₀H₆O-)PPh₂-κP ,κP}(PPh₃)(SO₃CF₃)] (10). All the complexes were characterized by ¹H NMR, ³¹P NMR, elemental analysis and mass spectrometry, including low-temperature NMR studies in the case of silver complexes. The molecular structures of 4 and 6 are determined by X-ray diffraction studies. Ruthenium complexes 2 and 3 promote catalytic hydrogenation of styrene and phenylacetylene with good turnover numbers.

Full text of DOI:10.1016/j.jorganchem.2006.06.040

Journal of Organometallic Chemistry 691 (2006) 4265–4272
www.elsevier.com/locate/jorganchem
Ruthenium(II), copper(I) and silver(I) complexes of large bite
bisphosphinite, bis(2-diphenylphosphinoxynaphthalen-1-yl)methane:
Application of Ru(II) complexes towards the hydrogenation
of styrene and phenylacetylene
a
b
a,
*
Benudhar Punji , Joel T. Mague , Maravanji S. Balakrishna
a
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
b
Department of Chemistry, Tulane University, New Orleans, LA 70118, USA
Received 25 May 2006; accepted 23 June 2006
Available online 11 July 2006
Abstract
Ruthenium(II), copper(I) and silver(I) complexes of large bite bisphosphinite Ph2P{(-OC10H6)(l-CH2)(C10H6O-)}PPh2 (1) are
described. Reactions of bisphosphinite 1 with [Ru(g6-p-cymene)(l-Cl)Cl]2 and RuCl2(PPh3)3 afford mono- and bis-chelate complexes
[RuCl(g6-p-cymene){g2-Ph2P{(-OC10H6)(l-CH2)(C10H6O-)}PPh2-jP,jP}]Cl (2) and trans-[RuCl2{g2-Ph2P{(-OC10H6)(l-CH2)-
(C10H6O-)}PPh2-jP,jP}2] (3), respectively. Treatment of 1 with CuX (X = Cl, Br and I) furnish 10-membered chelate complexes of
the type [Cu(X){g2-Ph2P(-OC10H6)(l-CH2)(C10H6O-)PPh2-jP,jP}] (4, X = Cl; 5, X = Br; 6, X = I), whereas [Cu(MeCN)4]PF6 affords
a bis-chelated cationic complex [Cu{g2-Ph2P(-OC10H6)(l-CH2)(C10H6O-)PPh2-jP,jP}2][PF6] (7). Reaction between 1 and AgOTf
produce both mono- and bis-chelated complexes [Ag{g2-Ph2P(-OC10H6)(l-CH2)(C10H6O-)PPh2-jP,jP}(SO3CF3)] (8) and [Ag{g2-
Ph2P(-OC10H6)(l-CH2)(C10H6O-)PPh2-jP,jP}2][SO3CF3] (9), respectively; whereas the similar reaction of 1 with[Ag(OTf)PPh3] affords
chelate complex of the type [Ag{g2-Ph2P(-OC10H6)(l-CH2)(C10H6O-)PPh2-jP,jP}(PPh3)(SO3CF3)] (10). All the complexes were char-
acterized by 1H NMR, 31P NMR, elemental analysis and mass spectrometry, including low-temperature NMR studies in the case of sil-
ver complexes. The molecular structures of 4 and 6 are determined by X-ray diffraction studies. Ruthenium complexes 2 and 3 promote
catalytic hydrogenation of styrene and phenylacetylene with good turnover numbers.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Bisphosphinite; Chelate complexes; Ruthenium(II), copper(I) and silver(I) complexes; Crystal structures; Hydrogenation reactions
1. Introduction
the catalytic process. Transition metal complexes contain-
ing bulky mono- and bisphosphines as catalyst in organic
transformation are well documented. Surprisingly, the uti-
lization of analogous bisphosphinite ligands in such reac-
tions are sparse although some of them are proved to be
efficient catalysts [2]. In this context, recently we have syn-
thesized an inexpensive large bite bisphosphinite, bis(2-
diphenylphosphinoxynaphthalen-1-yl)methane (1) and
explored its ligating behavior and catalytic properties
toward coupling reactions [3,4]. Since, the group 10 metal
precusors containing bisphosphines are known to give
interesting halide-bridged metal clusters and bimetallic
complexes, which inturn show metallophilic interactions
Synthesis of novel bisphosphine ligand systems to stabi-
lize transition metal chelates in low valent states is consid-
ered to be a most challenging task in view of their potential
usefulness in a variety of metal-mediated organic transfor-
mations [1]. Most of these phosphine ligands bear the
bulky substituents, where both the steric and electronic fac-
tors play a vital role for imposing regioselectivity during
*
Corresponding author. Tel.: +91 22 2576 7181; fax: +91 22 2576 7152/
2572 3480.
E-mail address: krishna@chem.iitb.ac.in (M.S. Balakrishna).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.06.040

4266
B. Punji et al. / Journal of Organometallic Chemistry 691 (2006) 4265–4272
and are rich in luminescence properties [5], we sought to
examine the reactivity of this large bite bisphosphinite 1
with the group 10 metals. As a part of interest in organo-
metallic chemistry and catalytic investigations [6], we
describe here the ruthenium(II), copper(I) and silver(I)
complexes of the bisphosphinite 1. The catalytic activity
of ruthenium(II)–bisphosphinite complexes towards hydro-
genation of styrene and phenylacetylene is also described.
(C10H6O-)PPh2-jP,jP}] (4, X = Cl; 5, X = Br; 6, X = I).
However, this is not true for the reactions of 1 with Ag(I)
and Au(I) metal precursors. For example, reaction of 1 with
AuCl(SMe2) gives either mononuclear chelate complex
[Au(Cl){g2-Ph2P(-OC10H6)(l-CH2)(C10H6O-)PPh2-jP,jP}]
or bridged binuclear complex [Au(Cl){l-Ph2P(-OC10H6)(l-
CH2)(C10H6O-)PPh2-jP,jP}Au(Cl)] depending upon the
stoichiometry, as we have reported previously [4]. The 31P
NMR spectra of the complexes 4–6 exhibit single resonance
at 92.6, 94.6 and 96.9 ppm, respectively. Although, the reac-
tion of 1 with CuX (X = Cl, Br, I) produced only the mono-
nuclear uni-chelate complexes, the reaction with 0.5 equiv.
of [Cu(MeCN)4PF6] afforded the cationic bis-chelated com-
2. Results and discussion
2.1. Ruthenium derivatives
The reaction of [Ru(g6-p-cymene)(l-Cl)Cl]2 with excess
of bisphosphinite Ph2P{(-OC10H6)(l-CH2)(C10H6O-)}PPh2
(1) in ethanol at 50 ꢁC afforded the cationic complex
[RuCl(g6-p-cymene){g2-Ph2P{(-OC10H6)(l-CH2)(C10H6-
O-)}PPh2-jP,jP}]Cl (2) in good yield. A large excess of
bisphosphinite was used to avoid the formation of phosph-
inite bridged bimetallic complex and lower temperature
was applied to prevent the loss of the arene [7]. The 31P
NMR spectrum of complex 2 shows a single resonance at
plex
[Cu{g2-Ph2P(-OC10H6)(l-CH2)(C10H6O-)PPh2-jP,
jP}2][PF6] (7) in good yield. Since the copper has high ten-
dency to adopt higher coordination numbers than the Ag(I)
or Au(I), we propose a tetrahedral geometry for complex 7.
The 31P NMR spectrum of the complex 7 shows a singlet at
97.3 ppm and the chemical shift due to PF6 appears as a
1
septet at ꢀ146.0 ppm with JPF coupling of 713 Hz. In the
mass spectrum, peak appears at m/z 1401.5 and 731.2 for
the cation (M+ꢀPF6) and M+ꢀ(1+PF6), respectively. Fur-
ther structural composition of complexes 4–7 comes from
1H NMR and microanalytical data. The structures of com-
plexes 4 and 6 have been confirmed by single crystal X-ray
analysis.
1
122.1 ppm. In H NMR spectrum, a singlet at 4.66 ppm
is observed for the CH2 protons of bisphosphinite, whereas
signals at 2.46 (septet), 1.49 (s) and 0.84 (d) ppm confirm
the presence of p-cymene moiety. In the mass spectrum,
the base peak appear at m/z 828.2 correspond to the ion
[{M+ꢀ(cymene+Cl)}+Na]. Treatment of RuCl2(PPh3)3
with two equivalents of bisphosphinite 1 in dichlorometh-
ane at room temperature resulted in the formation of a
bis-chelated trans complex [RuCl2{g2-Ph2P{(-OC10H6)(l-
CH2)(C10H6O-)}PPh2-jP,jP}2] (3). In the 31P NMR spec-
trum, a singlet is observed at 137.5 ppm, which indicates
the presence of only one type of phosphorus environment
confirming the trans arrangement. The mass spectrum of
complex 3 shows the isotopic pattern at m/z 805.3 and
807.3 for the ion (M+ꢀ(1+Cl)). Similarly, another set of
peak appears at m/z 769.3 corresponds to the ion
(M+ꢀ(1+Cl2)). Further support for the molecular compo-
X
Ph2
P
Ph
Ph2
P
P
2O
O
O
O
O
M
X
M
P
Ph2
P
Ph2
O
P
Ph2
4 M = Cu, X = Cl
5 M = Cu, X = Br
6 M = Cu, X = I
7 M = Cu, X = PF6
9 M = Ag, X = OTf
8 M = Ag, X = OTf
2.3. Silver derivatives
1
sition and structure comes from the H NMR and elemen-
The reaction of 1 with AgOTf in 1:1 molar ratio provides
a complex with composition [Ag(OTf)(1)] (8). The 31P
NMR spectrum of complex 8 at ꢀ50 ꢁC shows two doublets
centered at 117.7 ppm, because of the coupling with the two
silver nuclei, 107Ag and 109Ag. The Ag–P coupling constants
are 1J(109AgP) 564 and 1J(107AgP) 486 Hz. In the mass spec-
trum, the molecular peak due to the cation appears at
m/z = 776.9 for (M+ꢀOTf). This suggests that the complex
8 is bisphosphinite-chelated complex. Generally, 1:1 reac-
tion of AgOTf with bisphosphine ligands can afford two
types of binuclear tetrahedral complexes: (i) ligand chelate
to silver with the two anionic groups bridge the silver cen-
ters, for example [Ag2(l-SCN)2(dppf)2] or (ii) ligand as well
as anionic groups bridge between the two silver centers,
example [Ag2(l-CN)2(l-dppf)2] [8]. As the mass spectros-
copy data indicates the chelation of ligand to silver center,
we propose trifluoromethanesulfonate bridge binuclear
tal analysis data.
Cl-
Ph
Ph2
P
Cl
Ph2
P
P
2O
O
O
O
O
Ru
Cl
Ru
Cl
P
Ph2
O
P
Ph2
P
Ph2
2
3
2.2. Copper derivatives
The reactions of bisphosphinite 1 with CuX (X = Cl, Br,
I) are independent of stoichiometry and the reaction condi-
tions and afford exclusively the mononuclear 10-member
chelated complexes [Cu(X){g2-Ph2P(-OC10H6)(l-CH2)-

B. Punji et al. / Journal of Organometallic Chemistry 691 (2006) 4265–4272
4267
tetrahedral geometry for the complex 8. Similarly, the reac-
tion of 1 with AgOTf in a molar ratio 2:1 gives the cationic
complex [Ag{g2-Ph2P(-OC10H6)(l-CH2)(C10H6O-)PPh2-
jP,jP}2][SO3CF3] (9). The 31P NMR spectrum of complex
9 recorded at ꢀ50 ꢁC shows two doublets centered at
111.7 ppm with Ag–P coupling of 1J(109AgP) 489 and
1J(107AgP) 423 Hz. In the mass spectrum, a peak due to cat-
ion appears at m/z = 775.2 (M+ꢀ(1+OTf)). The treatment
of 1 with [Ag(OTf)(PPh3)] in dichloromethane at room tem-
perature leads to the formation of air stable complex
[Ag{g2-Ph2P(-OC10H6)(l-CH2)(C10H6O-)PPh2-jP,jP}-
(PPh3)(SO3CF3)] (10) in excellent yield. The 31P NMR spec-
trum of 10 exhibits four broad signals, two each at
113.3 ppm and 3.8 ppm, respectively, for bisphosphinite
and PPh3 centers. Even the low temperature NMR studies
(ꢀ50 ꢁC) did not resolve the signals to show the proper cou-
plings with 107Ag and 109Ag and also the 2JPP couplings. In
the mass spectrum, a peak at m/z = 774.8 is observed for the
ion (M+ꢀ(PPh3+OTf)). Further support for the molecular
composition and structural assignments came from 1H
NMR and microanalytical data.
in Figs. 1 and 2, respectively. The crystallographic data
and the details of the structure determination are given in
Table 1, while the selected bond lengths and bond angles
appear in Table 2.
In the structures of 4 and 6, the copper centers adopt
almost trigonal planar geometry with the bite angles of
122.21(2)ꢁ and 119.93(2)ꢁ, respectively. The structure of
complex 4 is similar to that of (PPh3)2CuCl [9]. The P1–
Cu–P2 bite angle in complex 4 is very large compared to
Ph2
P
OTf
O
O
Ag
PPh3
P
Ph2
10
Fig. 2. Molecular structure of [Cu(I){g2-Ph2P(-OC10H6)(l-CH2)-
(C10H6O-)PPh2-jP,jP}] (6) (ellipsoids represent 50% probability levels;
hydrogen atoms are omitted for clarity).
2.4. The crystal and molecular structures of complexes 4 and 6
Perspective views of the molecular structures of com-
plexes 4 and 6 with atom numbering schemes are shown
Table 1
Crystallographic data for complexes 4 and 6
Compound
4
6
Formula
C
767.66
45H34ClCuO2P2
C45H34CuIO2P2
859.11
Molecular weight
Crystal system
Crystal size (mm)
Space group
Monoclinic
0.12 · 0.14 · 0.14
P21/n (No. 14)
17.4180(10)
12.4200(9)
17.4730(10)
90
90.0450(10)
90
3780.0(4)
4
Monoclinic
0.09 · 0.14 · 0.18
C2/c (No. 15)
14.8040(10)
20.851(2)
12.4140(10)
90
110.0930(10)
90
3598.7(5)
4
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
qcalc (g cmꢀ3
)
1.349
0.771
1584
1.586
1.593
1728
l(Mo Ka) (mmꢀ1
F(000)
)
Temperature (K)
hmin–max (ꢁ)
100
1.6–28.3
1.04
0.0370
0.0938
100
1.8–28.2
1.05
0.0246
0.0624
Goodness-of-fit on F2
a
R1
wR2
b
Fig. 1. Molecular structure of [Cu(Cl){g2-Ph2P(-OC10H6)(l-CH2)-
(C10H6O-)PPh2-jP,jP}] (4) (ellipsoids represent 50% probability levels;
hydrogen atoms are omitted for clarity).
P
P
a
R1 = jFoj ꢀ jFcj/ jFoj.
P
P
2
2
1=2
b
wR2 ¼ f w½ðF 2o ꢀ F c2Þ ꢁ= ½wðF 2oÞ ꢁg
.

4268
B. Punji et al. / Journal of Organometallic Chemistry 691 (2006) 4265–4272
Table 2
complex 6. The Cu–P bond lengths in complexes 4 and 6
are significantly shorter than the corresponding Cu–P bond
lengths of trigonal planar complex, [(PPh3)2CuCl] (Cu–P1,
˚
Selected bond distances (A) and bond angles (ꢁ) for 4 and 6
˚
Bond distances (A)
Bond angles (ꢁ)
˚
2.272(2); Cu–P2, 2.260(2) A) and [(PPh3)2CuI] (Cu–P,
Complex 4
˚
Cu–Cl
Cu–P1
Cu–P2
P1–O1
P2–O2
P1–C1
P1–C7
P2–C34
P2–C40
2.209(1)
Cl–Cu–P1
Cl–Cu–P2
P1–Cu–P2
Cu–P1–O1
Cu–P1–C1
Cu–P1–C7
O1–P1–C1
O1–P1–C7
C1–P1–C7
C22–C23–C24
117.55(2)
120.23(2)
122.21(2)
114.68(4)
121.83(6)
112.11(6)
100.33(7)
102.66(7)
102.82(8)
121.28(13)
2.273(2) A), respectively [12]. This would suggest the signif-
2.219(1)
2.220(1)
1.637(1)
1.645(1)
1.812(2)
1.807(2)
1.807(2)
1.821(2)
icant p-accepting capacity of bisphosphinite ligand in both
the complexes. The Cu–Cl and Cu–I bond distances in 4
˚
˚
and 6 are 2.2097(5) A and 2.5175(4) A, respectively.
3. Catalytic properties of compounds 2 and 3
Complexes 2 and 3 are tested for the catalytic hydroge-
nation of styrene and phenylacetylene with molecular
hydrogen in THF solution at 80 ꢁC. Catalytic studies have
been performed without addition of organic bases, which
increases the catalytic activity of Ru(II) complexes [13].
We have studied the catalytic activity of the cationic com-
plex 2 and the neutral complex 3, both at 20 atm as well as
45-atm hydrogen pressure.
Using milder conditions than Bennet applied with the
catalyst [RuClH(C6H6)(PPh3)] [14], we detected 98% con-
version of styrene to ethylbenzene using 0.05 mol% of the
catalyst 2 at 80 ꢁC after 6 h (Fig. 3). The neutral complex
3 is slightly less active which shows about 95% conversion
after 7 h under similar reaction conditions. An increase in
the H2 pressure from 20 to 45 atm, resulted in 96% conver-
sion of styrene to ethylbenzene within 2.5 h with the cata-
lyst 2, whereas no significant improvement was observed
in the performance of catalyst 3. These catalyst precursors
are much better than the similar catalysts [RuCl(p-cym-
ene)(PPh2Py)]+ used by Moldes et al. [15], where they
observed 94% conversion of styrene to ethylbenzene with
0.5 mol% of catalyst after 24 h.
Complex 6
Cu–I
Cu–P
Cu–P_a
P–O
P–C1
2.517(1)
2.230(1)
2.230(1)
1.646(1)
1.812(2)
1.806(2)
1.400(2)
I–Cu–P
120.04(1)
120.04(1)
119.93(2)
115.22(5)
119.70(6)
113.58(6)
102.85(8)
100.45(7)
102.51(9)
119.82(19)
I–Cu–P_a
P–Cu–P_a
Cu–P–O
Cu–P–C1
Cu–P–C7
O–P–C1
O–P–C7
C1–P–C7
C22–C23–C22_a
P–C7
O–C13
the same in the chloro-bridged complex [Cu2(l-Cl)2(j2-
P,P-dppf)2] [10]. Similarly, the bite angle in complex 6 is
large compared to the same in the iodo-bridged complex
[Cu2(l-I)2(j2-P,P-dppf)2] [11]. Generally, copper complexes
of bisphosphine form halide-bridged chelate complexes
with tetrahedral geometry; however, chelate complexes of
copper with trigonal planar geometry are rare. To the best
of our knowledge, chelated copper complexes of bisphos-
phine with such a large bite angle is not seen in the litera-
ture. Because of these large bite angles of complexes 4 and
6, the angles at the bridgehead methylene carbon
(121.28(13)ꢁ and 119.82(19)ꢁ) are approximately 2–4ꢁ
greater than those found in the other chelate complexes
of 1 (see Table 3). Interestingly, in both the complexes
the bisphosphinite makes a twisted 10-membered chelate
ring with one of the naphthyl rings oriented almost orthog-
onal to the plane of the ring. There are no significant differ-
Complexes 2 and 3 are also active species for hydrogena-
tion of phenylacetylene to styrene and ethylbenzene. The
Cat. 2
Cat. 3
100
˚
ences between the Cu–P1 (2.2193(4) A) and Cu–P2
(2.2203(4) A) bond lengths of complex 4, whereas it is
exactly the same (Cu–P = Cu–P_a = 2.2305(5) A) in the
90
80
70
60
50
40
30
20
10
0
˚
˚
Table 3
Bite angles and bridgehead methylene angles in chelate complexes of
1 (L–L)
Complexes
(P–M–P) bite Bridgehead methylene Reference
angles (ꢁ)
angles (ꢁ)
Mo(CO)4(L–L)
CpRuCl(L–L)
NiCl2(L–L)
[(C3H5)Pd(L–L)]BF4
PtCl2(L–L)
CuCl(L–L)
CuI(L–L)
AuCl(L–L)
95.06(3)
93.94(7)
95.96(2)
98.95(3)
95.37(9)
122.21(2)
119.93(2)
132.56(4)
114.2(3)
114.7(6)
117.04(17)
114.5(3)
116.9(8)
121.28(13)
119.82(19)
122.2(3)
[4]
[3]
[4]
[4]
[3]
a
1
2
3
4
5
6
7
a
time (h)
[4]
Fig. 3. The hydrogenation of styrene using complexes 2 and 3. Styrene/
complex = 2000; solvent, THF (20 ml); 20 atm H2; 80 ꢁC.
a
This work.

B. Punji et al. / Journal of Organometallic Chemistry 691 (2006) 4265–4272
4269
ene)(l-Cl)Cl]2 [16], RuCl2(PPh3)3 [17], CuCl, CuBr [18],
[Cu(MeCN)4PF6] [19] and Ag(PPh3)OTf [20] were pre-
pared according to the published procedures. Other
reagents were used as obtained from commercial sources.
The 1H and 31P{1H} NMR (d in ppm) spectra were
obtained on a Varian VXR 300 or VRX 400 spectrometer
operating at frequencies of 300 or 400 and 121 or
162 MHz, respectively. The NMR spectra were recorded
in CDCl3 solutions with CDCl3 as an internal lock; TMS
and 85% H3PO4 were used as internal and external stan-
dards for 1H and 31P{1H} NMR, respectively. Positive
shifts lie downfield of the standard in all cases. Microanal-
yses were carried out on a Carlo Erba (Model 1106) ele-
mental analyzer. Mass spectra were recorded using
Waters Q-Tof micro(YA-105) instrument. Melting points
of all compounds were determined on Veego melting point
apparatus and are uncorrected. GC analyses were per-
formed on a Perkin–Elmer Clarus 500 GC fitted with
packed column.
phenylacetylene
styrene
100
90
80
70
60
50
40
30
20
10
0
ethylbenzene
1
5
9
13
17
21
time (h)
5.1. Synthesis of [RuCl(g6-p-cymene){g2-Ph2P-
{(-OC10H6)(l-CH2)(C10H6O-)}PPh2-jP,jP}]Cl (2)
Fig. 4. The hydrogenation of phenylacetylene using complex 2. Phenyl-
acetylene/complex = 2000; solvent, THF (20 ml); 20 atm H2; 80 ꢁC.
A suspension of ligand 1 (0.094 g, 0.14 mmol) and
[Ru(g6-p-cymene)(l-Cl)Cl]2 (0.02 g, 0.033 mmol) in ethanol
(10 ml) was heated at 50 ꢁC for 16 h to get a clear orange
color solution. The solvent was removed under reduced
pressure to get oily liquid, which was redissolved in acetone
and was cooled to ꢀ25 ꢁC to get yellow crystalline product
2. Yield: 91% (0.058 g), m.p.: 122–124 ꢁC. Anal. Calc. for
C55H48Cl2O2P2Ru: C, 67.76; H, 4.96. Found: C, 67.44; H,
reaction profile of a run with complex 2 at 20 atm and
80 ꢁC is shown in Fig. 4. Using the catalyst 2 (0.05 mol%,
80 ꢁC) at 20 atm of H2 pressure, phenylacetylene is hydro-
genated to 30% of styrene and 70% of ethylbenzene after
24 h. The alkyne hydrogenation is completed with in 3 h,
whereas styrene hydrogenation proceeded very slowly.
With increase in the H2 pressure from 20 to 45 atm, the
phenylacetylene was hydrogenated to 98% of ethylbenzene
after 8 h. The activity of the catalyst 3 was poor for the
hydrogenation of phenylacetylene at 20 atm, whereas its
performance is same as that of catalyst 2 at 45 atm of H2
pressure.
1
4.89%. H NMR (400 MHz, CDCl3): d 8.17 (d, 2H, Ar),
8.05 (t, 2H, Ar), 7.65 (d, 2H, Ar), 7.50–7.18 (m, 4H, cymene,
6H, Ar, 20H, OPPh2), 4.66 (s, 2H, Ar–CH2–Ar), 2.46 (sep-
tet, 1H, CH), 1.49 (s, 3H, CH3), 0.84 (d, 6H, C(CH3)2).
31P{1H} NMR (161.9 MHz, CDCl3): d 122.1 (s). MS (EI):
828.2 [{M+ꢀ(cymene+Cl)}+Na].
4. Conclusion
5.2. Synthesis of trans-[RuCl2{g2-Ph2P{(-OC10H6)-
(l-CH2)(C10H6O-)}PPh2-jP,jP}2] (3)
The bisphosphinite 1 forms mainly chelate complexes
with most of the transition metals. With copper(I) deriva-
tives it forms both chelated trigonal planar as well as bis-
chelated tetrahedral complexes, the former type of copper
complexes are very rare with bisphosphine systems. The
reactions with ruthenium derivatives produce both cationic
uni-chelated and neutral bis-chelated complexes under dif-
ferent reaction conditions. The reactions of 1 with silver
precursor exclusively form chelated tetrahedral complexes.
The ruthenium complexes 2 and 3 show excellent activity
for the hydrogenation of styrene and phenylacetylene.
A solution of the ligand 1 (0.057 g, 0.085 mmol) in 8 ml
of CH2Cl2 was added dropwise to the 6 ml dichlorometh-
ane solution of RuCl2(PPh3)3 (0.041 g, 0.042 mmol) at
room temperature and the reaction mixture was stirred
for 6 h. The solvent was evaporated under reduced pressure
and the residue obtained was washed with diethyl ether
(3 · 5 ml). The cream color residue was recrystallized from
a CH2Cl2/petroleum ether (b.p. 60–80 ꢁC) in (2:1) mixture
to get the product 3 of analytical purity at ꢀ25 ꢁC. Yield:
86% (0.055 g), m.p.: 188–190 ꢁC (dec.). Anal. Calc. for
C90H68Cl2O4P4Ru: C, 71.62; H, 4.54. Found: C, 71.46;
5. Experimental
1
H, 4.49%. H NMR (400 MHz, CDCl3): d 8.25 (d, 4H,
All experimental manipulations were carried out under
an atmosphere of dry nitrogen or argon using Schlenk tech-
niques. Solvents were dried and distilled prior to use by
conventional methods. Bis(phosphinite) 1 [3], [Ru(g6-cym-
Ar), 7.08–7.92 (m, 16H, Ar, 40H, OPPh2), 6.55 (d, 4H,
Ar), 4.74 (s, 4H, Ar–CH2–Ar). 31P{1H} NMR
(161.9 MHz, CDCl3):
d 137.5 (s). MS (EI): 805.3
(M+ꢀ(L+Cl)), 769.3 (M+ꢀ(L+Cl2)).

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B. Punji et al. / Journal of Organometallic Chemistry 691 (2006) 4265–4272
5.3. Synthesis of [Cu(Cl){g2-Ph2P(-OC10H6)-
(l-CH2)(C10H6O-)PPh2-jP,jP}] (4)
Ar–CH2–Ar). 31P{1H} NMR (161.9 MHz, CDCl3): d 97.3
1
(s, 4P), ꢀ146.0 (septet, 1P, PF6), JPF = 713 Hz. MS (EI):
1401.5, (M+ꢀPF6); 731.2, M+ꢀ(L+PF6).
A solution of CuCl (0.011 g, 0.111 mmol) in acetonitrile
(6 ml) was added dropwise to the 8 ml dichloromethane
solution of 1 (0.074 g, 0.111 mmol) at room temperature.
After 30 min of slow stirring, the resulted suspension was fil-
tered to get a clear solution. Then, the reaction solution was
concentrated to 8 ml under reduced pressure, which gave
colorless crystalline product of 4 at ꢀ30 ꢁC. Yield: 76%
(0.065 g), m.p.: 224 ꢁC (dec.). Anal. Calc. for C45H34ClO2-
5.7. Synthesis of [Ag{g2-Ph2P(-OC10H6)-
(l-CH2)(C10H6O-)PPh2-jP,jP}(SO3CF3)] (8)
To the 12 ml dichloromethane solution of ligand 1
(0.078 g, 0.117 mmol), AgOTf (0.03 g, 0.117 mmol) was
added and stirred the reaction mixture for 2 h. The clear
solution obtained was concentrated to 2 ml, diethyl ether
was added to precipitate out white stuff, which was filtered
and dried to obtain analytically pure product of 8. Yield:
82% (0.089 g), m.p.: 158–160 ꢁC (dec.). Anal. Calc. for
C46H34F3O5P2SAg: C, 59.69; H, 3.70; S, 3.46. Found: C,
1
P2Cu: C, 70.40; H, 4.46. Found: C, 70.32; H, 4.41%. H
NMR (400 MHz, CDCl3): d 8.17 (d, 2H, Ar), 8.01 (br s,
2H, Ar), 7.52 (t, 2H, Ar), 7.26–7.49 (m, 20H, OPPh2, 2H,
Ar), 7.05 (d, 2H, Ar), 6.72 (d, 2H, Ar), 4.95 (s, 2H, Ar–
CH2–Ar). 31P{1H} NMR (161.9 MHz, CDCl3): d 92.6 (s).
1
59.36; H, 3.68; S, 3.39%. H NMR (400 MHz, CDCl3): d
8.16 (d, 2H, Ar), 7.18–7.68 (m, 8H, Ar, 20H, OPPh2),
6.69 (br s, 2H, Ar), 4.92 (s, 2H, Ar–CH2–Ar). 31P{1H}
NMR (121.4 MHz, CDCl3 (ꢀ50 ꢁC)): d 117.7 (2d, 2P,
OPPh2, 1J(109AgP) 564, 1J(107AgP) 486 Hz) ppm. MS
(EI): 776.9, (M+ꢀOTf).
5.8. Synthesis of [Ag{g2-Ph2P(-OC10H6)-
(l-CH2)(C10H6O-)PPh2-jP,jP}2][SO3CF3] (9)
5.4. Synthesis of [Cu(Br){g2-Ph2P(-OC10H6)-
(l-CH2)(C10H6O-)PPh2-jP,jP}] (5)
This was synthesized by the procedure similar to that for
4, using CuBr (0.015 g, 0.104 mmol) and 1 (0.07 g,
0.104 mmol). Yield: 81% (0.069 g), m.p.: 240 ꢁC (dec.).
Anal. Calc. for C45H34BrO2P2Cu: C, 66.55; H, 4.22.
1
Found: C, 66.49; H, 4.19%. H NMR (400 MHz, CDCl3):
d 8.17 (d, 2H, Ar), 8.03 (br s, 2H, Ar), 7.51 (t, 2H, Ar),
7.26–7.48 (m, 20H, OPPh2, 2H, Ar), 7.04 (d, 2H, Ar),
6.71 (d, 2H, Ar), 4.95 (s, 2H, Ar–CH2–Ar). 31P{1H}
NMR (161.9 MHz, CDCl3): d 94.6 (s).
To a solution of the ligand 1 (0.106 g, 0.159 mmol) in
15 ml of CH2Cl2 was added AgOTf (0.02 g, 0.078 mmol)
and the reaction mixture was stirred for 3 h. The clear solu-
tion obtained was concentrated to 2 ml, added petroleum
ether to precipitate out white stuff, which was filtered and
dried to obtain analytically pure product of 9. Yield: 77%
(0.095 g), m.p.: 170–172 ꢁC (dec.). Anal. Calc. for
C91H68F3O7P4SAg: C, 68.55; H, 4.29; S, 2.01. Found: C,
5.5. Synthesis of [Cu(I){g2-Ph2P(-OC10H6)-
(l-CH2)(C10H6O-)PPh2-jP,jP}] (6)
1
This was synthesized by the procedure similar to that for
68.13; H, 4.19; S, 1.98%. H NMR (400 MHz, CDCl3): d
4, using CuI (0.025 g, 0.13 mmol) and
1
(0.088 g,
8.22 (d, 4H, Ar), 8.13 (d, 4H, Ar), 6.78–7.87 (m, 12H,
Ar, 40H, OPPh2), 6.71 (d, 4H, Ar), 4.91 (s, 4H, Ar–CH2–
Ar). 31P{1H} NMR (121.4 MHz, CDCl3 (ꢀ50 ꢁC)): d
ppm. MS (EI): 775.2, (M+ꢀ(L+OTf)).
5.9. Synthesis of [Ag{g2-Ph2P(-OC10H6)-
(l-CH2)(C10H6O-)PPh2-jP,jP}(PPh3)(SO3CF3)] (10)
0.13 mmol). Yield: 81% (0.091 g), m.p.: 242 ꢁC (dec.). Anal.
Calc. for C45H34IO2P2Cu: C, 62.91; H, 3.99. Found: C,
1
1
1
62.89; H, 3.92%. H NMR (400 MHz, CDCl3): d 8.16 (d,
111.7 (2d, 4P, OPPh2, J(109AgP) 489, J(107AgP) 423 Hz)
2H, Ar), 8.06 (br s, 2H, Ar), 7.50 (t, 2H, Ar), 7.29–7.38
(m, 20H, OPPh2, 2H, Ar), 7.06 (d, 2H, Ar), 6.71 (d, 2H,
Ar), 4.96 (s, 2H, Ar–CH2–Ar). 31P{1H} NMR
(161.9 MHz, CDCl3): d 96.9 (s).
5.6. Synthesis of [Cu{g2-Ph2P(-OC10H6)-
(l-CH2)(C10H6O-)PPh2-jP,jP}2][PF6] (7)
To a solution of the ligand 1 (0.053 g, 0.08 mmol) in
15 ml of CH2Cl2 was added Ag(PPh3)OTf (0.04 g,
0.077 mmol) and the reaction mixture was stirred for 2 h.
The solution was concentrated to 2 ml, added petroleum
ether to precipitate out white stuff, which was filtered and
dried to obtain analytically pure product of 10. It was
recrystallized from CH2Cl2/petroleum ether mixture to give
colorless crystalline product at room temperature. Yield:
91% (0.083 g), m.p.: 132 ꢁC (dec.). Anal. Calc. for
C64H49F3O5P3SAg: C, 64.71; H, 4.16; S, 2.69. Found: C,
To the solution of ligand 1 (0.073 g, 0.109 mmol) in
12 ml of dichloromethane [Cu(MeCN)4PF6] (0.02 g,
0.054 mmol) was added and the reaction mixture was stir-
red for 2 h. The suspension was filtered through celite to
remove insoluble impurities and the clear solution was con-
centrated to 3 ml, which on slow evaporation gave white
crystalline product of 7. Yield: 95% (0.079 g), m.p.:
112 ꢁC. Anal. Calc. for C90H68F6O4P5Cu: C, 69.92; H,
4.43. Found: C, 69.65; H, 4.46%. 1H NMR (400 MHz,
CDCl3): d 8.21 (d, 4H, Ar), 7.92 (d, 4H, Ar), 7.11–7.82
(m, 12H, Ar, 40H, OPPh2), 6.68 (d, 4H, Ar), 4.91 (s, 4H,
1
64.63; H, 4.09; S, 2.58%. H NMR (400 MHz, CDCl3): d
8.21 (d, 2H, Ar), 8.05 (d, 2H, Ar), 7.13–7.73 (m, 6H, Ar,
20H, OPPh2, 15H, PPh3), 6.79 (d, 2H, Ar), 4.73 (s, 2H,
Ar–CH2–Ar). 31P{1H} NMR (121.4 MHz, CDCl3

B. Punji et al. / Journal of Organometallic Chemistry 691 (2006) 4265–4272
4271
(ꢀ50 ꢁC)): d 113.3 (2d br, 2P, OPPh2, J(AgP) 342 Hz), 3.8
(2d br, 1P, PPh3, J(AgP) 228 Hz). MS (EI): 774.8,
(M+ꢀ(PPh3+OTf)).
and 608253. CCDC and copies of this information may
be obtained free of charge from the Director, CCDC, 12
Union Road, Cambridge CB2 1EZ, UK (fax: +44 1223
336 033; e-mail: deposit@ccdc.cam.ac.uk or www:
www://http.ccdc.cam.ac.uk). Supplementary data associ-
ated with this article can be found, in the online version,
at doi:10.1016/j.jorganchem.2006.06.040.
5.10. Catalytic hydrogenation reactions
All catalytic experiments were performed in a 50 ml or
100 ml stainless steel autoclave at 80 ꢁC pressurized with
hydrogen. In a typical experiment, a solution of the catalyst
precursor 2 or 3 (2.18 · 10ꢀ4 mmol) and the organic sub-
strate (styrene or phenylacetylene) (0.436 mmol) in 20 ml
of THF was placed into the reactor and was sealed. The
vessel was purged three times with hydrogen and then the
autoclave was pressurized with 20 or 45 atm of hydrogen.
The reaction mixture was stirred at 80 ꢁC and the extent
of conversion was determined by periodic GC analysis.
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