Ruthenium complexes of aminophosphine ligands and their use as pre-catalysts in the transfer hydrogenation of aromatic ketones: X-ray crystal structure of thiophene-2-(N-diphenylthiophosphino)methylamine

Article abstract of DOI:10.1016/j.poly.2010.12.011

Reaction of thiophene-2-methylamine with one or two equivalents of PPh ₂Cl in the presence of NEt₃, proceeds in thf to give thiophene-2-(N-diphenylphosphino)methylamine, 1a and thiophene-2-(N,N- bis(diphenylphosphino))methylamine, 2a

Full text of DOI:10.1016/j.poly.2010.12.011

Polyhedron 30 (2011) 796–804
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Ruthenium complexes of aminophosphine ligands and their use as pre-catalysts
in the transfer hydrogenation of aromatic ketones: X-ray crystal structure
of thiophene-2-(N-diphenylthiophosphino)methylamine
a
b
c
Murat Aydemir a, , Akın Baysal , Saim Özkar , Leyla Tatar Yıldırım
⇑
a Dicle University, Department of Chemistry, TR-21280 Diyarbakır, Turkey
b Middle East Technical University, Department of Chemistry, TR-06531 Ankara, Turkey
c Hacettepe University, Department of Physics Engineering, Beytepe, TR-06800 Ankara, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 5 July 2010
Accepted 10 December 2010
Available online 19 December 2010
Reaction of thiophene-2-methylamine with one or two equivalents of PPh2Cl in the presence of NEt3,
proceeds in thf to give thiophene-2-(N-diphenylphosphino)methylamine, 1a and thiophene-2-(N,
N-bis(diphenylphosphino))methylamine, 2a respectively, under anaerobic conditions. Oxidations of 1a
and 2a with aqueous hydrogen peroxide, elemental sulfur or gray selenium in thf gives the corresponding
oxides, sulfides and selenides [Ph2P(E)NHCH2-C4H3S] (E: O 1b, S 1c, Se 1d) and [(Ph2P(E))2NCH2-C4H3S],
(E: O 2b, S 2c, Se 2d) respectively, in high yield. Furthermore, two novel Ru(II) complexes with the P–N
Keywords:
Transfer hydrogenation
Catalysis
Aminophosphine
Bis(phosphino)amine
X-ray diffraction
ligands 1a and 2a were synthesized starting with the complex [Ru(g l-Cl)Cl]2. The com-
6-p-cymene)(
plexes were fully characterized by analytical and spectroscopic methods. 31P–{1H} NMR, DEPT, 1H–13C
HETCOR or 1H–1H COSY correlation experiments were used to confirm the spectral assignments. The
molecular structure of thiophene-2-(N-diphenylthiophosphino)methylamine was also elucidated by sin-
gle-crystal X-ray crystallography. Following activation by NaOH, compounds 3 and 4 catalyze the transfer
hydrogenation of acetophenone derivatives to 1-phenylethanol derivatives in the presence of iso-PrOH as
the hydrogen source. [Ru(Ph2PNHCH2-C4H3S)(
g 3 and [Ru((PPh2)2NCH2-C4H3S)-
6-p-cymene)Cl2],
(
g
6-p-cymene)Cl]Cl, 4 complexes are suitable catalyst precursors for the transfer hydrogenation of
acetophenone derivatives in 0.1 M iso-PrOH solution. Notably 4 acts as an excellent catalyst giving the
corresponding alcohols in excellent conversions up to 99% (TOF 6 744 hꢀ1). This transfer hydrogenation
is characterized by low reversibility under the experimental conditions.
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
organic synthesis [8,9], allowing transformations otherwise very
difficult or almost impossible to carry out. Today, the asymmetric
Synthesis of new aminophosphines to stabilize transition met-
als in low valent states is considered to be the most challenging
task in view of their potential utility in a variety of metal-mediated
organic transformations [1,2]. To date, a number of such systems
with a variety of backbone frameworks have been synthesized
and their transition metal chemistry has been explored [3,4].
Aminophosphines and bis(phosphino)amines with P–NH and
P–N–P skeletons, respectively, have proved to be versatile ligands,
and varying the substituents on both to P- and N-centers gives rise
the changes in the P–N–P angle and to conformation around the
P-centers [5,6]. Small variations in these ligands can cause signifi-
cant changes in their coordination behavior and the structural
features of the resulting complexes [7].
transfer hydrogenation [10] of prochiral ketones is one of the most
attractive methods for synthesizing optically active secondary
alcohols, which form an important class of intermediates for fine
chemicals and pharmaceuticals [11,12]. Catalytic transfer hydroge-
nation with the aid of a stable hydrogen reservoir is a useful alter-
native of using molecular hydrogen in catalytic hydrogenation
[13,14]. In transfer hydrogenation, organic molecules such as pri-
mary and secondary alcohols [15] or formic acid and its salts
[16] have been employed as the hydrogen source. The use of a
hydrogen reservoir has some advantages over the use of molecular
hydrogen since it avoids risks and the constrains associated with
hydrogen gas as well as the necessity for pressure vessels and other
equipments. 2-Propanol is a popular reactive solvent for transfer
hydrogenation reactions since it is easy to handle and is relatively
non-toxic, environmentally benign and inexpensive. The volatile
acetone by-product can also be easily removed to shift unfavorable
equilibria and can be hydrogenated back to 2-propanol by using
iridium catalyst at room temperature [17]. In general, asymmetric
Since its discovery, transfer hydrogenation using ruthenium
complexes as catalysts has been an increasingly useful tool in
⇑
Corresponding author. Tel.: +90 412 248 8550; fax: +90 412 248 8300.
E-mail address: aydemir@dicle.edu.tr (M. Aydemir).
0277-5387/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2010.12.011

M. Aydemir et al. / Polyhedron 30 (2011) 796–804
797
hydrogenation is mediated by a complex bearing Rh, Ru or Ir,
among which our focus has been Ru. One reason is that the Ru cat-
alysts have excellent performances [18,19]. Another reason is that
Ru enjoyed a cost advantage relative to other asymmetric hydroge-
nation metals such as Rh [20].
those found for closely related compounds [26,27]. 1a and 2a are
not stable and decompose rapidly on exposure to air or moisture.
When the reactions were monitored by 31P NMR spectroscopy,
the formation of P(O)Ph2PPh2 was observed, as indicated by signals
at d 34.60 (d) ppm and d ꢀ24.30 (d) ppm, {1J(PP) 226 Hz}. Solutions
of 1a and 2a in CDCl3, prepared under anaerobic conditions, are
also unstable and decompose gradually to give oxide and
bis(diphenylphosphino)monoxide [P(O)Ph2PPh2] derivatives.
1a and 2a were fully characterized by multinuclear NMR, infra-
red spectroscopy and microanalysis. All the compounds gave rea-
sonable microanalyses results. In the 1H NMR spectrum, the NH
resonance of 1a was observed as slightly broad pseudo-triplet or
doublet of triplets at 2.40 ppm due to the multiple coupling 3J(CHNH)
Herein we describe the synthesis of two compounds thiophene-2-
(N-diphenylphosphino)-methylamine (1a) and thiophene-2-(N,N-
bis(diphenylphosphino))methylamine (2a) through a single step
reaction of thiophene-2-methylamine with one or two equivalents
of diphenylchlorophosphine, respectively. Oxidation of 1a and 2a
with aqueous hydrogen peroxide, elemental sulfur or gray sele-
nium in thf gives the corresponding oxides, sulfides and
selenides [Ph2P(E)NHCH2-C4H3S] (E: O 1b, S 1c, Se 1d) and
[(Ph2P(E))2NCH2-C4H3S], (E: O 2b, S 2c, Se 2d), respectively. The
compounds were isolated from the reaction solution and fully
characterized by elemental analysis, IR and multi-nuclear NMR
spectroscopies. The X-ray crystal structure of thiophene-2-(N-
diphenylthiophosphino)methylamine, [Ph2P(S)NHCH2-C4H3S] was
determined, and pertinent features of this structure were de-
scribed. Based on these findings and our continuing interest in
developing more efficient and stable catalysts [21–23], we also
report here the synthesis of Ru(II) complexes [Ru(Ph2PNHCH2-
2
and J(NHP) and was confirmed by H/D exchange experiments. In
addition, the methylene groups give doublet of doublet at
4.28 ppm (3J 6.40 and 6.60 Hz) and triplet at 4.64 ppm (3J
10.40 Hz) for 1a and 2a, respectively. The phenyls carbons,
however, display well-resolved signals in their 13C-{1H} NMR
spectra.
To probe the reactivity of the new ligands, reactions with aque-
ous hydrogen peroxide, elemental sulfur and gray selenium were
carried out. The oxides 1b [Ph2P(O)NHCH2-C4H3S] and 2b
[(Ph2P(O))2NCH2-C4H3S] were easily prepared by addition of excess
C4H3S)(g 3 and [Ru((PPh2)2NCH2-C4H3S)(g
6-p-cymene)Cl2], 6-p-
cymene)Cl]Cl, 4 and their use as catalysts in the transfer hydroge-
aqueous hydrogen peroxide to 1a or 2a in thf, respectively. The 31
P
nation of ketones.
NMR spectra of 1b and 2b showed singlets (CDCl3) at d(P)
23.84 ppm and 30.68 ppm which are shielded by 17.86 and
29.15 ppm compared to the parent compounds 1a or 2a, respec-
tively. Characteristic J(31P–13C) coupling constants of the carbons
of the phenyls rings were observed in the 13C NMR spectra, which
are consistent with the literature values [28]. In the IR spectrum,
2. Results and discussion
2.1. Synthesis of the ligands and their chalcogenides
we can identify
t
(P@O) at 1189 and 1209 cmꢀ1 for 1b and 2b,
As shown in Scheme 1, thiophene-2-(N-diphenylphosphino)-
methylamine, [Ph2PNHCH2-C4H3S] 1a and thiophene-2-(N,N-
bis(diphenylphosphino))methylamine, [(Ph2P)2NCH2-C4H3S] 2a
were prepared from the commercially available starting material
thiophene-2-methylamine and one or two equivalents of PPh2Cl
in the presence of triethylamine by aminolysis [24,25] in thf at
0 °C, respectively. The 31P NMR spectra of 1a and 2a showed single
resonances at d(P) 41.70 and 59.83 ppm respectively, similar to
respectively. The sulfides 1c, 2c and selenides 1d, 2d analogs were
prepared by the addition of elemental S and gray Se to 1a and 2a in
thf, respectively. The 31P NMR showed single resonances (CDCl3) at
d(P) 57.78 and 71.23 ppm for 1c and 2c, respectively. The IR spec-
trum of 1c and 2c exhibit characteristic band at 650 and 652 cmꢀ1
due to
t(P@S) stretching, respectively. Compounds 1d and 2d ini-
tially analyzed by 31P NMR spectroscopy, which exhibited singlet
Scheme 1. Synthesis of thiophene-2-(N-diphenylphosphino)methylamine, [Ph2PNHCH2-C4H3S] and thiophene-2-(N,N-bis(diphenylphosphino))methylamine, [(Ph2P)2NCH2-
C4H3S] and their chalcogenides. (i) 1 equiv. Ph2PCl, thf; (ii) 2 equiv. Ph2PCl, thf; (iii) 1 equiv. H2O2 or elemental S or gray Se; (iv) 2 equiv. H2O2 or elemental S or gray Se.

798
M. Aydemir et al. / Polyhedron 30 (2011) 796–804
1
resonances at 57.46 and 70.61 ppm, with J(31P–77Se) of 758.54 and
red microcrystalline powder (Scheme 2). 1a was expected to cleave
the [Ru( -Cl)Cl]2 dimer to give the corresponding
6-p-cymene)(
790.56 Hz, respectively, as expected [29]. The IR spectra have
g
l
t
(P@Se) bands at 552 and 566 cmꢀ1 for 1d and 2d respectively.
complex 3 via monohapto coordination of the aminophosphine
group. The 31P NMR spectrum of 3 shows a single resonance at
61.0 ppm, in line with the values previously observed for similar
compounds [35,36]. Analysis by 1H NMR reveals this compound
to be diamagnetic, exhibiting signals corresponding to the aro-
matic rings for 3 at 7.97–7.42 ppm. Another set of signals consist-
ing of two doublets centered at 5.29 and 5.10 ppm are due to the
presence of the aromatic protons in the p-cymene group (the pres-
ence of one (broad) or two signals corresponding to CH p-cymene
hydrogens in the 1H NMR spectra is consistent with a Cs symmetry
of complex and with free rotation of the arene ligand [37,38]), this
information is complemented by the presence of signals at 2.65
and 0.87 ppm due to the CH and CH3 of the iso-propyl groups of
the p-cymene moiety. Finally, a signal due to the presence of the
methyl in the p-cymene group is observed at 1.98 ppm. The NH
resonance of 3 was observed slightly broad pseudo-quartet or dou-
blet of triplet [39] at 3.58 ppm due to the multiple coupling 3J(CHNH)
Furthermore, in the 13C-{1H} NMR spectra of sulfides and selenides,
Jð coupling constants of the carbons of the phenyls rings
31PA13CÞ
were observed, which is consistent with the literature values
[30,31]. In addition, the structural compositions of 1d and 2d have
also been confirmed by IR and elemental analysis. Furthermore, in
the 13C NMR spectra, the coupling between the i-carbon and phos-
phorus in the oxidized P(V) compounds is quite large 1JPC = 129.78,
102.81 and 90.54 Hz for 1b–d and JPC = 126.76, 101.61 and
91.55 Hz for 2b–d respectively, corresponding to O, S, Se oxidized
species [32] (for details see supplementary data)
1
Crystal of 1c suitable for a single crystal X-ray diffraction study
was obtained by slow diffusion of diethylether into a solution of
the compound in dichloromethane over several days. The P atom
in
the
thiophene-2-(N-diphenylthiophosphino)methylamine,
[Ph2P(S)NHCH2-C4H3S], 1c has a distorted tetrahedral coordination
sphere consisting of one N, one S and two C atoms of the phenyl
rings at normal bond distances. The bond angles within the coordi-
nation sphere range from 101.55(17)° to 118.08(14)° (see the OR-
TEP [33] in Fig. 1).
2
and J(NHP) and was confirmed by H/D exchange experiments. In
addition, the methylene group gives doublet of doublets at
3.81 ppm (J = 6.80 and 6.40 Hz) for 3. Furthermore in the 13C
There are two H-bonds in the structure. As shown in the crystal
packing diagram (Fig. 2a), the compound 1c is made up bilateral
group via H-bond which is lined up nearly along the b-axis of the
unit cell. The first H-bond is intermolecular [N–Hꢁ ꢁ ꢁS1i] with
Dꢁ ꢁ ꢁA distance and D–Hꢁ ꢁ ꢁA angle of 3.617(4) Å and 168(3)°,
respectively [symmetry code: (i) 1 ꢀ x, 1 ꢀ y, 1 ꢀ z]. The second
H-bond is intramolecular [C2–H2ꢁ ꢁ ꢁS1] with Dꢁ ꢁ ꢁA distances and
D–Hꢁ ꢁ ꢁA angle of 3.355 Å and 114°, respectively. The molecule of
1c has three dimensional conformation. Dihedral angels between
the planar ring planes in the molecule were calculated with
MERCURY [34]. Dihedral angles between planes P1–P2, P1–P3
and P2–P3 are 66.77°, 43.68° and 70.91°, respectively, where P1:
C1/C6; P2: C7/C12; P3: S2/C14/C17 (Fig. 2b).
NMR spectrum of 3, Jð
coupling constants of the carbons of
31PA13CÞ
the phenyl rings were observed, which are consistent with the lit-
erature values [30,40]. The phenyls carbons, however, display well-
resolved signals in their 13C NMR spectra. In the compound 3, the
coupling between i-carbon and the phosphorus is relatively large,
1J(PC) 51.6 Hz, while the coupling between o-carbon and the
2
phosphorus relatively small J(PC) 10.4 Hz. The coupling between
m-carbon and the phosphorus is 3J(PC) 10.1 Hz and the coupling be-
tween p-carbon and the phosphorus is observed at 4J(PC) 6.0 Hz. The
structure of the 3 was further confirmed by IR spectroscopy and
microanalysis, and found to be in good agreement with the
theoretical values.
We also examined some simple coordination chemistry of 2a
with [Ru(
tion between Ru(II) dimeric precursor and bis(phosphino)amine,
2a is profoundly affected by the molar ratio of [Ru(
6-p-cyme-
ne)( -Cl)Cl]2 as well as the steric and electronic properties of the
donor phosphorus atoms. The reaction of 2a with 1/2 equivalent
[Ru( -Cl)Cl]2 yielded a dark yellow product. The
6-p-cymene)(
g l-Cl)Cl]2 precursor (Scheme 2). The reac-
6-p-cymene)(
2.2. Synthesis and characterization of the metal complexes
g
g
6-p-cymene)
l
The reaction of stoichiometric amounts of [Ru(
-Cl)Cl]2 and [Ph2PNHCH2-C4H3S], 1a affords complex [Ru(Ph2-
PNHCH2-C4H3S)(
6-p-cymene)Cl2], 3 in high yield as an air stable
(l
g
l
g
Fig. 1. Molecular structure of thiophene-2-(N-diphenylthiophosphino)methylamine, [Ph2P(S)NHCH2-C4H3S] (1c), showing the atomic numbering scheme.

M. Aydemir et al. / Polyhedron 30 (2011) 796–804
799
Fig. 2. (a) Intermolecular hydrogen bonding geometry in the crystal packing, (b) the plane view of molecular conformation of the compound 1c.
Scheme 2. Synthesis of the [Ru(Ph2PNHCH2-C4H3S)(
g
6-p-cymene)Cl2], 3 and [Ru((PPh2)2NCH2-C4H3S)(
g g l-
6-p-cymene)Cl]Cl, 4 complexes. (i) 1/2 equiv. [Ru( 6-p-cymene)(
Cl)Cl]2, thf; (ii) 1/2 equiv. [Ru( -Cl)Cl]2, thf; (iii)1 equiv. [Ru(
g
6-p-cymene)(
l
g
6-p-cymene)(
l-Cl)Cl]2, thf.
31P NMR spectrum of the product indicated that it is a mixture of
[Ru((PPh2)2NCH2-C4H3S)(g
6-p-cymene)Cl]Cl, 4, in high yield. Com-
two products, 4 and 5 as shown in (Scheme 2 and Fig. 3). In the
plexation reaction was straight- forward, with coordination to
ruthenium being carried out at room temperature. The initial color
change, i.e., from clear orange to deep red [42], attributed to the di-
mer cleavage most probably by the bis(phosphino)amine ligand.
The 31P NMR spectrum of 4 shows a single resonance at d
88.2 ppm which is consistent with both the proposed structure
and literature values [43,44]. In the 13C NMR spectrum through-
space P–C coupling was observed, which is consistent with the lit-
erature values [45,46]. Furthermore, 1H NMR spectral data of 4 is
consistent with the structure proposed. In the 1H NMR spectrum,
4 is characterized by isopropyl methyl doublets, at d 1.23 ppm
31P NMR spectrum,
a singlet at 78.1 ppm was assigned to
compound 5 [41]. Complex 4 exhibits a singlet at 88.2 ppm for
monochelating [(PPh2)2NCH2-C4H3S]. Compound 4, with one
[(PPh2)2NCH2-C4H3S] ligand and compound 5, with two
[(PPh2)2NCH2-C4H3S] ligands, show two sets of 31P NMR reso-
nances with relative intensities of 1:2 which are consistent with
these structural formulations, respectively. The compound 4 was
also prepared in its pure form separately using different molar ra-
tios (excess [Ru(
[(PPh2)2NCH2-C4H3S] with one equivalent of [Ru(
ne)( -Cl)Cl]2) affords only the corresponding mono(chelate)
g
6-p-cymene)(
l
-Cl)Cl]2). The reaction of
g
6-p-cyme-
l
and g
6-p-cymene doublets at d 5.45 and 5.28 ppm (for details

800
M. Aydemir et al. / Polyhedron 30 (2011) 796–804
Fig. 3. The 31P NMR spectra of reaction mixture containing complexes 4 and 5; (i) reaction of 2a with 1/2 equiv. [Ru(
(excess) [Ru( -Cl)Cl]2.
6-p-cymene)(
g l-Cl)Cl]2; (ii) reaction of 2a with 1 equiv.
6-p-cymene)(
g
l
see experimental). The structural composition of the complex has
also been confirmed by IR and elemental analysis.
the presence of NaOH are necessary to observe appreciable conver-
sions (entries 5–12). The base facilitates the formation of ruthe-
nium alkoxide by abstracting proton of the alcohol and
subsequently alkoxide undergoes b-elimination to give ruthenium
hydride, which is an active species in this reaction. This is the
mechanism proposed by several research groups on the studies
of ruthenium catalyzed transfer hydrogenation reaction by metal
hydride intermediates [50,51]. Namely, role of the base is to gener-
ate a more nucleophilic alkoxide ion which would rapidly attack
the ruthenium complex responsible for dehydrogenation of iso-
PrOH. As shown in Table 3, high conversions can be achieved with
the 3 and 4 catalytic systems. Next, we increased the substrate-
to-catalyst ratio to observe the effect on the catalytic efficiency
(entries 7–10). Increasing the substrate-to-catalyst ratio do not
cause any change in conversion of the product in most cases, how-
ever the reaction time was increased. Remarkably, the transfer
hydrogenation of acetophenone could be achieved in 99% yield
even when the substrate-to-catalyst ratio reached 1000:1. In addi-
tion, performing the reaction in air, slowed down the reaction but
did not affect yield of the product. Results obtained from optimiza-
tion studies indicated clearly that the excellent yields were
achieved in the reduction of acetophenone to 1-phenylethanol
when 3 and 4 were used as the precursor in 30 and 10 min, respec-
tively, with a substrate-catalyst molar ratio (100:1) in iso-PrOH at
82 °C (Table 3). It should be pointed out that complexes 3 and 4 are
2.3. Catalytic transfer hydrogenation of acetophenone derivatives
Recently, we have reported that the novel half-sandwich com-
plexes, based on the ligands with P–N and P–O backbone, are ac-
tive catalysts in the reduction of aromatic ketones [47]. These
ligands are attractive and also widely used in ruthenium com-
plexes for catalytic hydrogenations reactions [48,49]. The observed
activity of these complexes has encouraged us to investigate other
analogous ligands and other transition metal complexes of these li-
gands. So, extending our program in the design and study to devel-
op useful catalysts, complexes 3 and 4 were tested as catalysts in
transfer hydrogenation of aromatic ketones in iso-PrOH solution.
The catalytic hydrogenation of acetophenone derivatives was con-
ducted using NaOH as a promoter (Scheme 3). It was found that
both complexes catalyze the reduction of ketones to the corre-
sponding alcohols via hydrogen transfer from iso-PrOH.
The synthesized complexes 3 and 4 were used as a precursor for
the catalytic transfer hydrogenation of the acetophenone by iso-
PrOH/NaOH as a reducing system. The results are summarized in
Table 3. At room temperature no appreciable formation of 1-phen-
ylethanol was observed (Table 3, entries 1 and 2) and also the cat-
alytic activity [Ru(g l-Cl)Cl]2 under the applied
6-p-cymene)(
more active catalysts than the parent complex: [Ru(
g
6-p-cyme-
experimental conditions was found to be negligible. In addition,
ne)( -Cl)Cl]2 (41% maximum yield in 24 h) with a 1/14 complex/
l
as can be inferred from the Table 3, the precatalysts as well as
Scheme 3. Hydrogen transfer from iso-PrOH to acetophenone derivatives.

M. Aydemir et al. / Polyhedron 30 (2011) 796–804
801
NaOH ratio [52]. When we compare the catalytic activity of com-
plexes 3 and 4 to the other structurally similar complexes, [53–
56] specially complex 4 shows higher activity [57–60].
4H, 3J 6.80 and 14.80 Hz), 7.37–7.42 (m, m and p-hydrogen of
phenyls, 6H), 7.21 (d, H-5, 1H, 3J 4.80 Hz), 6.95 (dd, H-4, 1H, 3J
3.60 and 4.80), 6.89 (d, H-3, 1H, 3J 3.60 Hz), 4.28 (dd, –CH2–, 2H,
3J 6.40 and 6.60 Hz), 2.40 (t, –NH–, 1H, J 6.40 Hz); 13C NMR (d in
ppm rel. to TMS, J Hz, in CDCl3): 145.75 (d, C-2, 3J(31P-13C) 7.00
Hz), 140.89 ppm (d, i-carbons of phenyls, 1J(31P–13C) 12.07 Hz),
131.47 (d, o-carbons of phenyls, 2J(31P–13C) 20.12 Hz), 128.63 (s,
p-carbons of phenyls), 128.35 (d, m-carbons of phenyls,
3J(31P–13C) 6.24 Hz), 126.69 (C-4), 124.47 (C-5), 124.34 (C-3),
45.16 (–CH2–); assignment was based on the 1H–13C HETCOR
and 1H–1H COSY spectra; 31P NMR (d in ppm rel. to H3PO4, in
The catalytic reduction of acetophenone derivatives were all
tested with the conditions optimized for acetophenone. It is note-
worthy that the complexes 3 and 4 differ in reactivity (Table 4).
The reactions with the aminophosphine-Ru(II), 3 proceeds more
slowly than those with the mono-chelate(phosphino)amine-Ru(II),
4. The mono-chelate(phosphino)amine-Ru(II), 4 have proved to be
excellent catalyst precursors in transfer hydrogenation of acetophe-
none derivatives, leading to corresponding alcohols in 10 min. (up to
95–99% yield). But, the examination of the results indicates clearly
that the highest conversion was achieved in the reduction of aceto-
phenone derivatives by using mono-chelate(phosphino)amine-
Ru(II), 4 as the catalyst precursor. Furthermore, complexes 3 and 4
show very high activity for most of the ketones. The introduction
of electron withdrawing substituents, such as F, Cl and Br to the para
position of the aryl ring of the ketone decreases the electron density
of the C@O bond giving rise to easier hydrogenation [61–63].
CDCl3): 41.70 (s). Selected IR (KBr pellet, in cmꢀ1):
(P–Ph) 1439, (N–H) 3371; Anal. Calc. for C17H16NSP: C, 68.67;
t(P–N) 856,
t
t
H, 5.42; N, 4.71; found: C, 68.53; H, 5.32; N, 4.57%.
3.3.2. Thiophene-2-(N,N-bis(diphenylphosphino))methylamine,
[(Ph2P)2NCH2-C4H3S], (2a)
Chlorodiphenylphosphine (0.45 g, 1.95 mmol) was added to a
stirred solution of thiophene-2-methylamine (0.11 g, 0.97 mmol)
and triethylamine (0.20 g, 1.95 mmol) in thf (50 mL) at 0 °C with
vigorous stirring. The mixture was stirred at room temperature
for 2 h and the white precipitate (triethylammonium chloride)
was filtered off under argon and the solvent removed under re-
duced pressure. The residue was then washed with cold diethyl
ether (2 ꢂ 15 mL) and dried in vacuo to produce a yellow viscous
oily compound 2a [65] (Yield: 0.44 g, 94%); 1H NMR (d in ppm
rel. to TMS, J Hz, in CDCl3): 7.38 (dd, o-hydrogen of phenyls, 8H,
3J 5.60 and 7.66 Hz), 7.28–7.34 (m, m and p-hydrogen of phenyls,
12H), 7.07 (d, H-5, 1H, 3J 5.20 Hz), 6.77 (dd, H-4, 1H, 3J 3.60 and
5.20 Hz), 6.45 (d, H-3, 1H, 3J 3.60 Hz), 4.64 (t, –CH2–, 2H, 3J
10.40 Hz); 13C NMR (d in ppm rel. to TMS, J Hz, in CDCl3): 143.01
(C-2), 139.09 ppm (d, i-carbons of phenyls, 1J(31P–13C) 14.08 Hz),
132.89 (d, o-carbons of phenyls, 2J(31P–13C) 22.13 Hz), 128.81 (s,
p-carbons of phenyls), 128.10 (d, m-carbons of phenyls,
3J(31P–13C) 6.04 Hz), 126.89 (C-3), 126.25 (C-4), 125.24 (C-5),
51.53 (–CH2–); assignment was based on the 1H–13C HETCOR
and 1H–1H COSY spectra; 31P NMR (d in ppm rel. to H3PO4, in
3. Experimental
3.1. Materials and methods
Unless otherwise stated, all reactions were carried out under an
atmosphere of argon using conventional Schlenk glass-ware, sol-
vents were dried using established procedures and distilled under
argon immediately prior to use. Analytical grade and deuterated
solvents were purchased from Merck. PPh2Cl and thiophene-
2-methylamine are purchased from Fluka and were used as
received. [Ru(g l-Cl)Cl]2 [64] was prepared according
6-p-cymene)(
to literature procedure. The IR spectra were recorded on a Mattson
1000 ATI UNICAM FT-IR spectrometer as KBr pellets. 1H (400.1
MHz), 13C NMR (100.6 MHz) and 31P NMR spectra (162.0 MHz)
were recorded spectra on a Bruker Avance 400 spectrometer, with
d referenced to external TMS and 85% H3PO4 respectively. Elemen-
tal analysis was carried out on a Fisons EA 1108 CHNS-O instru-
ment. Melting points were recorded by Gallenkamp Model
apparatus with open capillaries.
CDCl3): 59.83(s). Selected IR (KBr pellet, in cmꢀ1):
(P–Ph) 1439; Anal. Calc. for C29H25NSP2: C, 72.34; H, 5.23; N,
2.91; found: C, 72.16; H, 5.08; N, 2.74%.
t(P–N–P) 814,
t
3.2. GC analyses
3.4. Synthesis and Characterization of ligands and their chalcogenides
See supplementary data.
GC analyses were performed on a HP 6890N Gas Chromato-
graph equipped with capillary column (5% biphenyl, 95% dimethyl-
siloxane) (30 m ꢂ 0.32 mm ꢂ 0.25
lm). The GC parameters were
3.5. Synthesis of ruthenium complexes
as follows for transfer hydrogenation of ketones; initial tempera-
ture, 110 °C; initial time, 1 min; solvent delay, 4.48 min; tempera-
ture ramp 80 °C/min; final temperature, 200 °C; final time,
21.13 min; injector port temperature, 200 °C; detector tempera-
3.5.1. [Ru(Ph2PNHCH2-C4H3S)(
g
6-p-cymene)Cl2], (3)
-Cl)Cl]2 (0.30 mg, 0.49
To a solution of [Ru(
g
6-p-cymene)(
l
mmol) in CH2Cl2, a solution (thf, 30 mL) of [Ph2PNHCH2-C4H3S],
1a (0.29 mg, 0.98 mmol) was added. The resulting reaction mixture
was allowed to proceed with stirring at room temperature for 1 h.
After this time, the solution was filtered and the solvent evapo-
rated under vacuum, the solid residue thus obtained was washed
with diethyl ether (3 ꢂ 15 mL) and then dried under vacuum. Fol-
lowing recrystalization from diethylether/CH2Cl2, a red crystalline
powder was obtained (yield: 0.55 g, 93%; mp: 180–182 °C); 1H
NMR (d in ppm rel. to TMS, J Hz, in CDCl3): 7.97 (dd, 4H, 3J = 4.8
and 9.2 Hz, o-protons of phenyls), 7.42–7.53 (m, 6H, m- and p- pro-
tons of phenyls), 7.07 (d, 1H, 3J = 4.8 Hz, H-5), 6.79 (dd, 1H, 3J = 3.2
and 4.8 Hz, H -4)), 6.75 (d, 1H, 3J = 3.2 Hz, H-3), 5.29 (d, 2H,
3J = 6.4 Hz, aromatic hydrogens of p-cymene), 5.10 (d, 2H,
3J = 6.0 Hz, aromatic hydrogens of p-cymene), 3.81 (dd, 2H,
3J = 6.4 and 6.8 Hz, –CH2–), 3.58 (m, 1H, NH), 2.65 (m, 1H, –CH–
of p-cymene), 1.98 (s, 3H, CH3-Ph of p-cymene), 0.87 (d, 6H,
3J = 6.8 Hz, (CH3)2CHPh of p-cymene); 13C NMR (d in ppm rel. to
ture, 200 °C, injection volume, 2.0 lL.
3.3. Synthesis and Characterization of ligands
3.3.1. Thiophene-2-(N-diphenylphosphino)methylamine,
[Ph2PNHCH2-C4H3S], (1a)
Chlorodiphenylphosphine (0.23 g, 0.97 mmol) was added drop-
wise over a period of 30 min to a stirred solution of thiophene-2-
methylamine (0.11 g, 0.97 mmol) and triethylamine (0.10 g,
0.97 mmol) in thf (50 mL) at 0 °C. The mixture was stirred at room
temperature for 1 h and the white precipitate (triethylammonium
chloride) was filtered off under argon and the solvent removed un-
der reduced pressure. The residue was then washed with cold
diethyl ether (2 ꢂ 15 mL) and dried in vacuo to produce a clear, yel-
low viscous oily compound 1a (Yield: 0.27 g, 93%); 1H NMR (d in
ppm rel. to TMS, J Hz, in CDCl3): 7.50 (dd, o-hydrogen of phenyls,

802
M. Aydemir et al. / Polyhedron 30 (2011) 796–804
Table 1
TMS,
J Hz, in CDCl3): 17.49 (CH3Ph of p-cymene), 21.36
Crystal data and experimental details of structural analysis of thiophene-2-(N-
diphenylthiophosphino)methylamine, [Ph2P(S)NHCH2-C4H3S] (1c).
((CH3)2CHPh of p-cymene), 30.09 (–CH– of p-cymene), 42.32 (–
CH2–), 86.17, 91.19 (aromatic carbons of p-cymene), 94.07,
108.41 (quaternary carbons of p-cymene), 124.22 (C-5), 124.75
(C-3), 126.57 (C-4), 128.21 (d, 3J = 10.1 Hz, m-carbons of phenyls),
130.86 (d, 4J = 6.0 Hz, p-carbons of phenyls), 132.89 (d, 2J =
10.4 Hz, o-carbons of phenyls), 134.93 (d, 1J = 51.6 Hz, i-carbons
of phenyls), 143.05 (d, 3J = 7.0 Hz, C-2); assignment was based on
the 1H–13C HETCOR and 1H–1H COSY spectra; 31P NMR (d in
ppm rel. to H3PO4, in CDCl3): 61.0 (s); Selected IR (KBr pellet, in
Compound
Ph2P(S)NHCH2-C4H3S
17H16NPS2
Formula
C
Formula weight
Crystal system
Space group
a (Å)
329.42
Orthorhombic
Pbca
12.9375(16)
b (Å)
13.8701(18)
c (Å)
18.1301(19)
3253.4(7)
8
1.345
0.418
1376
Volume (Å3)
Z
cmꢀ1):
27H30NPSRuCl2 (603.6 g/mol) C, 53.73; H, 5.01; N, 2.32; found:
t(P–N) 990, t(P–Ph) 1440, t(N–H) 3301; Anal. Calc. for
C
Dcalc. (Mg/m3)
C, 53.59; H, 4.93; N 2, 29%.
V (mmꢀ1
F(0 0 0)
)
3.5.2. [Ru((PPh2)2NCH2-C4H3S)(
g
6-p-cymene)Cl]Cl, (4)
6-p-cymene)(
To a solution of [Ru(g l-Cl)Cl]2 (0.596 g, 0.980
h, k, l ranges
0 ? 16, ꢀ17 ? 0, 0 ? 22
Reflections collected/unique
Parameters/restrains
Goodness of fit on F2
3300–2326
194/2
1.181
mmol) in 10 mL thf, a solution (thf, 15 mL) of [(PPh2)2NCH2-
C4H3S], 2a (0.469 g, 0.980 mmol) was added. The resulting reaction
mixture was allowed to proceed under stirring at room tempera-
ture for 1 h. After this time, the solution was filtered off and the
solvent evaporated under vacuum, the solid residue thus obtained
was washed with diethyl ether (3 ꢂ 15 mL) and then dried under
vacuum. Following recrystallization from diethylether/CH2Cl2, a
R indices [I > 2
R indices [all data]
r
(I)]
R1 = 0.0656, wR2 = 0.2304
R1 = 0.1024, wR2 = 0.2476
0.001
0.901 and ꢀ0.786
(D/r)
max
Largest difference peak and hole (e/Å3)
red crystalline powder was obtained (yield: 0.71 g, 92%; mp:
1H NMR (d
250 °C (dec.);
in ppm rel. to TMS, J Hz, in CDCl3): 7.72
(dd, 8H, 3J = 7.2 and 13.6, o-protons of phenyls), 7.54 (dd, 4H,
3J = 6.6 and 12.4, p-protons of phenyls), 7.32 (m, 8H, m-protons
of phenyls), 7.03 (d, 1H, 3J = 5.2 Hz, H-5), 6.66 (dd, 1H, 3J = 3.6
and 5.2 Hz, H-4), 6.39 (d, 1H, 3J = 3.6, H-3), 5.45 (d, 2H,
3J = 5.6 Hz, aromatic hydrogens of p-cymene), 5.28 (d, 2H, 3J =
5.6 Hz, aromatic hydrogens of p-cymene), 4.45 (t, 2H, 3J = 11.6 Hz,
–CH2–), 2.81 (m, 1H, –CH– of p-cymene), 2.26 (s, 3H, CH3-Ph of
p-cymene), 1.23 (d, 6H, 3J = 6.8 Hz, (CH3)2CHPh of p-cymene); 13C
NMR (d in ppm rel. to TMS, J Hz, in CDCl3): 18.63 (CH3Ph of p-cym-
ene), 22.21 ((CH3)2CHPh of p-cymene), 31.01 (–CH– of p-cymene),
47.68 (–CH2–), 77.97, 79.05 (aromatic carbons of p-cymene), 95.92,
100.20 (quaternary carbons of p-cymene), 125.32 (C-5), 126.55 (C-
4), 127.86 (C-3), 127.41 (t, 3J = 4.0 Hz, m-carbons of phenyls),
129.84 (d, 1J = 57.3 Hz, i-carbons of phenyls), 132.83 (t,
4J = 6.0 Hz, p-carbons of phenyls), 134.31 (t, 2J = 5.5 Hz, o-carbons
of phenyls), 140.54 (C-2); assignment was based on the 1H–13C
HETCOR and 1H–1H COSY spectra; 31P NMR (d in ppm rel. to
H3PO4, in CDCl3): 88.21 (s); Selected IR (KBr pellet, in cmꢀ1):
Table 2
Selected bond lengths (Å), torsion and bond angles (°) for solid state molecular
structure of 1c.
P–S1
P–N
P–C1
P–C7
S2–C14
S2–C17
N–C13
C13–C14
C1–P–N–C13
C7–P–N–C13
S1–P–N–C13
1.9549(15)
1.669(3)
1.808(4)
1.810(4)
1.681(5)
1.633(6)
1.488(5)
1.485(6)
ꢀ179.1(3)
ꢀ68.7(3)
56.0(3)
N–P–C1
N–P–C7
N–P–S1
C1–P–C7
S1–P–C1
S1–P–C7
P–N–C13
C14–S2–C17
S2–C14–C13
S2–C14 –C15
N–C13–C14
101.55(17)
102.26(18)
118.08(14)
106.95(18)
113.56(15)
113.03(14)
116.8(3)
93.4(2)
122.7(3)
113.0(3)
111.6(3)
Table 3
Transfer hydrogenation of acetophenone with iso-PrOH catalyzed by [Ru(Ph2PNHCH2-
C4H3S)(
g
6-p-cymene)Cl2], 3 and [Ru((PPh2)2NCH2-C4H3S)(
g
6-p-cymene)Cl]Cl, 4.
t(P–N–P) 984, t(P–Ph) 1440; Anal. Calc. for C39H39NSP2RuCl2
(787.7 g/mol): C, 59.47; H, 4.99; N, 1.78; found: C, 59.39; H, 4.93;
N, 1.74%.
i
Entry Catalyst
S/C/NaOH Time
Conversionh TOF(hꢀ1
)
1
2
3
4
5
6
7
8
3a
4a
3b
4b
3c
4c
3d
4d
3e
4e
3f
100:1:5
100:1:5
100:1
1 h
1 h
1 h
<1
<1
<5
<5
3.6. General procedure for the transfer hydrogenation of ketones
100:1
1 h
100:1:5
100:1:5
500:1:5
500:1:5
1000:1:5
1000:1:5
100:1:5
100:1:5
30 min
15 min
2 h
30 min
3 h
98
97
97
97
96
99
196
388
49
194
32
Typical procedure for the catalytic hydrogen transfer reaction: a
solution of ruthenium complexes [Ru(Ph2PNHCH2-C4H3S)(g6
-
-
p-cymene)Cl2], 3 (0.005 mmol) or [Ru((PPh2)2NCH2-C4H3S)(g6
p-cymene)Cl]Cl, 4, NaOH (0.025 mmol) and the corresponding
ketone (0.5 mmol) in degassed iso-PrOH (5 mL) were refluxed for
30 min for 3 and 10 min for 4. After this period a sample of the
reaction mixture was taken off, diluted with acetone and analyzed
immediately by GC. Conversions obtained are related to the resid-
ual unreacted ketone.
9
10
11
12
13
1 h
99
5 min (30) 23 (97)
5 min (10) 62 (97)
276 (194)
744 (582)
<2
4f
Ru-precursorg 100:1:14
41
24
Ru-precursor: [Ru(
g
-p-cymene)([l-Cl)Cl]2.
a
At room temperature; acetophenone/Ru/NaOH, 100:1:5.
Refluxing in iPrOH; acetophenone/Ru, 100:1, in the absence of base.
Refluxing the reaction in air.
b
c
d
e
f
3.7. X-ray diffraction structure analysis
Refluxing in iso-PrOH; acetophenone/Ru/NaOH, 500:1:5.
Refluxing in iso-PrOH; acetophenone/Ru/NaOH, 1000:1:5.
Refluxing in iso-PrOH; acetophenone/Ru/NaOH, 100:1:5.
Intensity data of the compound 1c were measured at 295 K on
an Enraf–Nonius CAD4 diffractometer fitted with graphite-mono-
[Ru(g l-Cl)Cl]2.
6-p-cymene)(
g
h
i
chromated Mo K
a (k = 0.71073 Å). The x/2h scan technique was
Determined by GC (three independent catalytic experiments).
employed to measure data up to a maximum Bragg angle of
26.29°. The data were corrected for absorption. The structure was
Referred at the reaction time indicated in column; TOF = (mol product/mol
Ru(II)Cat.) ꢂ hꢀ1
.

M. Aydemir et al. / Polyhedron 30 (2011) 796–804
803
Table 4
Transfer hydrogenation results for substituted acetophenones with the Catalyst
Appendix A. Supplementary material
systems: [Ru(Ph2PNHCH2-C4H3S)(
g
6-p-cymene)Cl2],
3
and [Ru((PPh2)2NCH2-
CCDC 756881; contains the supplementary crystallographic
data for Compound 1c;. These data can be obtained free of charge
via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the
Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge
CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.
cam.ac.uk.
C4H3S)(
g
-p-cymene)Cl]Cl, 4.a
c
Entry
Catalyst
3
R
Time (min)
Conversion (%)b
TOF (hꢀ1
)
1
2
3
4
5
6
7
8
H
4-F
30
30
30
30
30
30
10
10
10
10
10
10
97
99
98
97
96
94
97
99
98
97
96
95
194
198
196
194
192
188
582
594
588
582
576
570
4-Cl
4-Br
2-MeO
4-MeO
H
Appendix A. Supplementary data
4
4-F
9
4-Cl
4-Br
2-MeO
4-MeO
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.poly.2010.12.011.
10
11
12
a
References
Catalyst (0.005 mmol), substrate (0.5 mmol), iso-PrOH (5 mL), NaOH
(0.025 mmol), 82 °C, 30 min for 3 and 10 min for 4, respectively, the concentration
of acetophenone derivatives is 0.1 M.
[1] L.H. Pignolet, Homogeneous Catalysis with Metal Phosphine Complexes,
Plenum Press, New York, 1983. pp. 137–165.
b
Purity of compounds is checked by NMR and GC (three independent catalytic
[2] P.W.N.M. Van Leeuwen, Organometallics 16 (1997) 3027.
[3] A.M.Z. Slawin, M.B. Smith, J.D. Woollins, J. Chem. Soc. Rev., Dalton. Trans
(1998) 1537.
experiments), yields are based on methyl aryl ketone.
c
TOF = (mol product/mol Cat.) ꢂ hꢀ1
.
[4] M.S. Balakrishna, P.P. George, S.M. Mobin, Polyhedron 24 (2005) 475.
[5] H.–J. Chen, J.M. Barendt, R.C. Haltiwanger, T.G. Hill, A.D. Norman, Phosphorus,
Sulfur 26 (1986) 155.
[6] M. Aydemir, A. Baysal, G. Öztürk, B. Gümgüm, Appl. Organometal. Chem. 23
(2009) 108.
[7] P. Bhattacharyya, J.D. Woollins, Polyhedron 14 (1995) 3367.
[8] G. Zassinovich, G. Mestroni, S. Gladiali, Chem. Rev. 92 (1992) 1051.
[9] T. Ikariya, A.J. Blacker, Acc. Chem. Res. 40 (2007) 1300.
[10] S. Gladiali, G. Mestroni, in: M. Beller, C. Bolm (Eds.), Transition Metal for
Organic Synthesis, vol. 2, Wiley-VCH, Weinheim, 1998, pp. 97–119.
[11] H. Siegel, V. Himmele, Angew. Chem., Int. Ed. Engl. 92 (1980) 182.
[12] C. Botteghi, S. Paganelli, A. Schionato, M. Marchetti, Chirality 3 (1991) 355.
[13] R.A.W. Johnstone, A.H. Wilby, I.D. Entwistle, Chem. Rev. 85 (1985) 129.
[14] M. Yig˘it, B. Yig˘it, I. Özdemir, E. Çetinkaya, B. Çetinkaya, Appl. Organometal.
Chem. 20 (2006) 322.
solved by direct methods using the program SHELX [66] and refined
by a full-matrix least-squares procedure based on F2. All non-
hydrogen atoms were refined with anisotropic thermal parame-
ters. Hydrogen atom of N were located from difference maps and
refined with isotropic thermal parameters. All other hydrogen
atoms were placed on idealized positions riding on their carrier
atoms with isotropic displacement parameters. The crystal data
and structure refinement details for compound 1c are given in
Table 1. Selected bond distances and bond angles are listed in
Table 2. Additional data, including fractional atomic co-ordinates
and their equivalent isotropic displacement parameters, hydrogen
atom coordinates, anisotropic temperature factors, and a list of
observed and calculated structure factors for compound have been
deposited from Cambridge Crystallographic Data Center as deposi-
tion No: CCDC 756881 for 1c.
[15] R. Noyori, M. Yamakawa, S. Hashiguchi, Acc. Chem. Res. 23 (1990) 345.
[16] S. Ram, R.E. Ehrenkaufer, Synthesis (1988) 91.
[17] S. Özkar, R.G. Finke, J. Am. Chem. Soc. 127 (2005) 4800.
[18] R. Noyori, T. Ohkuma, M. Kitamura, H. Takaya, N. Sayo, H. Kumobayashi, S.
Akutagawa, J. Am. Chem. Soc. 109 (1987) 5856.
[19] T. Ohkuma, H. Ooka, S. Hashiguchi, T. Ikariya, R. Noyori, J. Am. Chem. Soc. 117
(1995) 2675.
[20] H. Shimizu, I. Nagasaki, T. Satio, Tetrahedron 61 (2005) 5405.
[21] M. Aydemir, A. Baysal, Polyhedron 29 (2010) 1219.
[22] M. Aydemir, A. Baysal, N. Meric, C. Kayan, M. Tog˘rul, B. Gümgüm, Appl.
Organometal Chem. 24 (2010) 215.
4. Conclusion
[23] M. Aydemir, N. Meric, F. Durap, A. Baysal, M. Tog˘rul, J. Organomet. Chem. 695
In summary, we have shown the facile synthesis of two amino-
phosphine ligands and their derivatives including oxides, sulfides
and selenides. All these new compounds were characterized using
multi nuclear NMR, IR spectroscopies and microanalysis and also
one representative structure was studied by single crystal X-ray
diffraction analyses. Furthermore, we synthesized two new octahe-
(2010) 1392.
[24] A. Baysal, M. Aydemir, F. Durap, B. Gümgüm, S. Özkar, L.T. Yıldırım, Polyhedron
26 (2007) 3373.
[25] M. Aydemir, A. Baysal, F. Durap, B. Gümgüm, S. Özkar, L.T. Yıldırım, Appl.
Organomet. Chem. 23 (2009) 467.
[26] A.D. Burrows, M.F. Mahon, M.T. Palmer, J. Chem. Soc., Dalton Trans. (2000)
1669.
[27] M. Aydemir, A. Baysal, G. Öztürk, B. Gümgüm, Appl. Organometal Chem. 23
(2009) 108.
[28] M. Aydemir, A. Baysal, B. Gümgüm, J. Organometal Chem. 693 (2008)
3810.
[29] A.M.Z. Slawin, J. Wheatley, M.V. Wheatley, J.D. Woollins, Polyhedron 22 (2003)
1397.
dral Ru(II) complexes of formula [Ru(Ph2PNHCH2-C4H3S)(
g
6-p-
cymene)Cl2] and [Ru((PPh2)2NCH2-C4H3S)(
g
6-p-cymene)Cl]Cl
which were fully characterized. Complexes, being stable towards
decomposition, were tested as precatalysts in the hydrogen trans-
fer reaction (HTR) of acetophenone derivatives in basic iso-PrOH.
These compounds were formed to be efficient catalysts in the
transfer hydrogenation reaction of ketones. The [Ru((PPh2)2NCH2-
[30] F. Majoumo, P. Lönnecke, O. Kühl, E. Hey-Hawkins, Z. Anorg. Allg. Chem. 630
(2004) 305.
_
[31] M. Aydemir, A. Baysal, N. Gürbüz, I. Özdemir, B. Gümgüm, S. Özkar, N. Çaylak,
L.T. Yıldırım, Appl. Organometal Chem. 14 (2010) 17.
[32] Q. Zhang, G. Hua, P. Bhattacharrya, A.M.Z. Slawin, J.D. Woollins, J. Chem. Soc.,
Dalton Trans. (2003) 3250.
[33] L.J. Farrugia, J. Appl. Cryst. ORTEP-3 30 (1997) 565.
[34] C.F. Macrae, P.R. Edgington, P. McCabe, E. Pidcock, G.P. Shields, R. Taylor, M.
Towler, J Van de Streek, J. Appl. Cryst. MERCURY 39 (2006) 453.
[35] A.M.Z. Slawin, J. Wheatley, J.D. Woollins, Polyhedron 23 (2004) 2569.
[36] A.M.Z. Slawin, J. Wheatley, J.D. Woollins, Eur. J. Inorg. Chem. (2005) 713.
[37] E. De la Encarnacion, J. Pons, R. Yanez, J. Ros, Inorg. Chim. Acta 358 (2005)
3272.
C4H3S)(g
6-p-cymene)Cl]Cl, catalytic system demonstrates remark-
able catalytic activity and in a certain case, alcohols with up to 99%
conversion could be obtained even when the substrate-to-catalyst
molar ratio reached 1000:1. Future investigations are aiming at the
development of an asymmetric version of this process.
Acknowledgement
[38] I. Moldes, E. De la Encarnacion, J. Ros, A. Alvarez-Larena, J.F. Piniella, J.
Organometal Chem. 566 (1998) 165.
[39] Q. Zhang, G. Hua, P. Bhattacharrya, A.M.Z. Slawin, J.D. Woollins, Dalton Trans.
(2003) 3250.
[40] O. Akba, F. Durap, M. Aydemir, A. Baysal, B. Gümgüm, S. Özkar, J. Organometal
Chem. 694 (5) (2009) 731.
Partial support of this work by Turkish Academy of Sciences and
Dicle University (Project number: DÜAPK 05-FF-27) is gratefully
acknowledged.

804
M. Aydemir et al. / Polyhedron 30 (2011) 796–804
[41] Preparation of trans-[Ru((PPh2)2NCH2-C4H3S)2Cl2], 5: To a solution of [Ru(g6
p-cymene)( -Cl)Cl]2 (149 mg, 0.243 mmol) in 10 mL thf, a solution (thf, 30 mL)
of (PPh2)2NCH2-C4H3S, (469 mg, 0.972 mmol) was added. The resulting
-
[50] Doucet, T. Ohkuma, K. Murata, T. Yokozawa, M. Kozawa, E. Katayama, F. A.
England, T. Ikariya, R. Noyori, Angew. Chem. Int. Ed. Engl. 37 (1998) 1703–
1707.
l
1
reaction mixture was allowed to proceed under stirring at room temperature
for 1 h. After this time, the solution was filtered off and the solvent evaporated
under vacuum, the solid residue thus obtained was washed with diethyl ether
(3 ꢂ 15 mL) and then dried under vacuum (Scheme 1). Following
recrystalization from diethylether/CH2Cl2, a scarlet crystalline powder was
obtained (yield 506 mg, 91.5%), m.p. 251–253 °C. 1H NMR (400.1 MHz, CDCl3)
d = 7.11–7.56 (m, 40H, o-, m- and p- protons of phenyls), 6.96 (d, 2H,
3J = 4.20 Hz, H-5), 6.60 (dd, 2H, 3J = 2.80 and 4.20 Hz, H-4), 6.43 (d, 2H,
3J = 2.80 Hz, H-3), 4.66 (t, 4H, 3J = 5.20 Hz, –CH2–); 13C NMR (100.6 MHz,
CDCl3): d = 48.14 (–CH2–), 125.23 (C-5), 126.38 (C-4), 126.78 (m-carbons of
phenyls), 127.76 (C-3), 129.61 (p-carbons of phenyls), 134.83 (o-carbons of
phenyls), 137.30 (i-carbons of phenyls), 141.16 (C-2); assignment was based
on the 1H–13C HETCOR and 1H–1H COSY spectra; 31P NMR (162 MHz, CDCl3):
[51] M.J. Palmer, M. Will, Tetrahedron: Asymmetry 10 (1999) 2045.
[52] R. Tribo, S. Munoz, J. Pons, R. Yanez, A. Alvarez-Larena, J.F. Piniella, J. Ros, J.
Organomet. Chem. 690 (2005) 4072.
[53] C. Ganesamoorthy, M.S. Balakrishna, J.T. Mague, J. Organomet. Chem. 694
(2009) 3390.
[54] R. Ceron-Camacho, V. Gomez-Benitez, R. Le Lagadec, D. Morales-Morales, R.A.
Toscano, J. Mol. Catal. A 247 (2006) 124.
[55] A. Bacchi, M. Balordi, R. Cammi, L. Elviri, C. Pelizzi, F. Picchioni, V. Verdolino, K.
Goubitz, R. Peschar, P. Pelagatti, Eur. J. Inorg. Chem. (2008) 4462.
[56] M.S. Balakrishna, K. Ramaswamy, R.M. Abhyankar, J. Organomet. Chem. 560
(1998) 131.
[57] (a) M.S. Balakrishna, R. Panda, D.C. Smith Jr., A. Klaman, S.P. Nolan, J.
Organomet. Chem. 599 (2000) 159;
d = 78.05 (s); IR, (KBr):
t
= 993 (P–N–P), 1436 (P–Ph)cmꢀ1. C58H50N2S2P4RuCl2
(b) K. Mashima, K.H. Kusano, T. Ohta, R. Noyori, H. Takaya, J. Chem. Soc., Chem.
Commun. (1989) 1208.
(1135.1 g/mol): calcd. C 61.37, H 4.44, N 2.47; found C 61.29, H 4.39, N 2.41.
[42] A.M. Maj, K.M. Michal, I. Suisse, F. Agbossou, A. Mortreux, Tetrahedron:
Asymmetry 10 (1999) 831.
[43] M.S. Balakrishna, R. Panda, D.C. Smith Jr, A. Klaman, S.P. Nolan, J. Organometal
[58] M. Aydemir, A. Baysal, J. Organomet. Chem. 695 (2010) 2506.
[59] K. Mashima, K.–H. Kusano, N. Sato, Y.–I. Matsumara, K. Nozaki, H.
Kumobayashi, N. Sayo, Y. Hori, T. Ishizaki, S. Akutawaga, H. Takaya, J. Org.
Chem. 59 (1994) 3064.
Chem. 599 (2000) 159.
[44] M.S. Balakrishna, K. Ramaswarmy, R.M. Abhyankar, J. Organometal Chem. 560
[60] T.S. Venkatakrishnan, S.K. Mandal, R. Kannan, S.S. Krisnamurthy, M. Nethaji, J.
Organomet. Chem. 692 (2007) 1875.
(1998) 131.
[45] E. Lindler, M. Mohr, C. Nachtigal, R. Favzi, G. Henkel, J. Organometal Chem. 595
[61] J.W. Faller, A.R. Lavoie, Organometallics 20 (2001) 5245.
[62] I. Özdemir, S. Yasßar, Trans. Met. Chem. 30 (2005) 831.
[63] P. Pelagatti, M. Carcelli, F. Calbiani, C. Cassi, L. Elviri, C. Pelizzi, U. Rizzotti, D.
Rogolino, Organometallics 24 (2005) 5836.
(2000) 166.
[46] M. Hariharasarma, C.H. Lake, C.L. Watkins, G.M. Gray, J. Organometal Chem.
580 (1999) 328.
[47] M. Aydemir, A. Baysal, N. Meric, B. Gümgüm, J. Organometal Chem. 694 (2009)
[64] M.A. Bennet, G.B. Robertson, A.K. Smith, J. Organomet. Chem. 43 (1972) C41.
[65] K. Song, H. Gao, F. Liu, J. Pan, L. Guo, S. Zai, Q. Wu, Eur. J. Inorg. Chem. (2009)
3016.
2488.
[48] Y. Chen, S. Yekta, A.K. Yudin, Chem. Rev. 103 (2003) 3155.
[49] T. Jerphagnon, J.L. Renaud, C. Bruneau, Tetrahedron: Asymmetry 15 (2004)
2101.
[66] G.M. Sheldrick, A short history of SHELX, Acta Cryst. SHELX A64 (2008) 112.