Ruthenium, rhodium and iridium complexes of the furfuryl-2-(N- diphenylphosphino)methylamine ligand: Molecular structure and catalytic activity

Article abstract of DOI:10.1016/j.poly.2012.05.009

The reaction of furfurylamine with two equivalents of PPh₂Cl in the presence of Et₃N affords furfuryl-2-(N,N-bis(diphenylphosphino) amine), (Ph₂P)₂NCH₂-C₄H₃O (1). The corresponding ruthenium(II) complex trans-[Ru((PPh₂) ₂NCH₂-C₄H₃O)₂Cl ₂] (3) was synthesized by reacting 1 with [Ru(η⁶-p- cymene)(μ-Cl)Cl]₂. The reaction of furfurylamine with one equivalent of PPh₂Cl gives Ph₂PNHCH₂-C ₄H₃O (2). The reaction of 2 with [Ru(η⁶-p- cymene)(μ-Cl)Cl]₂, [Ru(η⁶-benzene)(μ-Cl)Cl] ₂, [Rh(μ-Cl)(cod)]₂ and [Ir(η⁵-C ₅Me₅)(μ-Cl)Cl]₂ yields the complexes [Ru(Ph₂PNHCH₂-C₄H₃S) (η⁶-p-cymene)Cl₂] (4), [Ru(Ph₂PNHCH ₂-C₄H₃O)(η⁶-benzene)Cl ₂] (5), [Rh(Ph₂PNHCH₂-C₄H ₃O)(cod)Cl] (6) and [Ir(Ph₂PNHCH₂-C ₄H₃O)(η⁵-C₅Me ₅)Cl₂] (7), respectively. All the complexes were isolated from the reaction solution and fully characterized by analytical and spectroscopic methods. The structure of [Ru(Ph₂PNHCH ₂-C₄H₃O)(η⁶-p-cymene)Cl ₂] (4) was also determined by single crystal X-ray diffraction. Complexes 3-7 are suitable precursors forming highly active catalysts in the transfer hydrogenation of a variety of simple ketones. Notably, the catalysts obtained by using the ruthenium complexes [Ru(Ph₂PNHCH ₂-C₄H₃O)(η⁶-p-cymene)Cl ₂] (4) and [Ru(Ph₂PNHCH₂-C₄H ₃O)(η⁶-benzene)Cl₂] (5) are much more active in the transfer hydrogenation, converting the carbonyls to the corresponding alcohols in 97-99% yields (TOF ≤300 h^-1), compared to analogous rhodium and iridium complexes and the trans-Ru(II)-p-cymene bis(phosphino)amine complex.

Full text of DOI:10.1016/j.poly.2012.05.009

Polyhedron 42 (2012) 142–148
Contents lists available at SciVerse ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Ruthenium, rhodium and iridium complexes
of the furfuryl-2-(N-diphenylphosphino)methylamine ligand: Molecular structure
and catalytic activity
a
a
a
a
a
b
Cezmi Kayan a, , Nermin Meric , Murat Aydemir , Akın Baysal , Duygu Elma , Bünyamin Ak , Ertan Sßahin ,
⇑
c
c
_
Nevin Gürbüz , Ismail Özdemir
a Dicle University, Department of Chemistry, 21280 Diyarbakır, Turkey
b Atatürk University, Department of Chemistry, 25240 Erzurum, Turkey
c
_
Inönü University, Department of Chemistry, 44280 Malatya, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
The reaction of furfurylamine with two equivalents of PPh2Cl in the presence of Et3N affords furfuryl-2-
Received 25 February 2012
Accepted 8 May 2012
Available online 29 May 2012
(N,N-bis(diphenylphosphino)amine), (Ph2P)2NCH2-C4H3O (1). The corresponding ruthenium(II) complex
trans-[Ru((PPh2)2NCH2-C4H3O)2Cl2] (3) was synthesized by reacting 1 with [Ru(
The reaction of furfurylamine with one equivalent of PPh2Cl gives Ph2PNHCH2-C4H3O (2). The reaction of
g l-Cl)Cl]2.
6-p-cymene)(
2 with [Ru(
Cl)Cl]2 yields the complexes [Ru(Ph2PNHCH2-C4H3S)(
benzene)Cl2] (5), [Rh(Ph2PNHCH2-C4H3O)(cod)Cl] (6) and [Ir(Ph2PNHCH2-C4H3O)(
respectively. All the complexes were isolated from the reaction solution and fully characterized by ana-
lytical and spectroscopic methods. The structure of [Ru(Ph2PNHCH2-C4H3O)(
6-p-cymene)Cl2] (4) was
g
6-p-cymene)(
l
-Cl)Cl]2, [Ru(
g
6-benzene)(
l
-Cl)Cl]2, [Rh(
l
-Cl)(cod)]2 and [Ir(
g
5-C5Me5)(
l
-
-
g
6-p-cymene)Cl2] (4), [Ru(Ph2PNHCH2-C4H3O)(g6
Keywords:
Aminophosphine
Transfer hydrogenation
Ruthenium
Rhodium
Iridium
g
5-C5Me5)Cl2] (7),
g
also determined by single crystal X-ray diffraction. Complexes 3–7 are suitable precursors forming highly
active catalysts in the transfer hydrogenation of a variety of simple ketones. Notably, the catalysts
X-ray diffraction
obtained by using the ruthenium complexes [Ru(Ph2PNHCH2-C4H3O)(g
6-p-cymene)Cl2] (4) and
[Ru(Ph2PNHCH2-C4H3O)(g
6-benzene)Cl2] (5) are much more active in the transfer hydrogenation, con-
verting the carbonyls to the corresponding alcohols in 97–99% yields (TOF 6300 hꢀ1), compared to anal-
ogous rhodium and iridium complexes and the trans-Ru(II)-p-cymene bis(phosphino)amine complex.
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
Aminophosphines and bis(phosphino)amines with P–NH and
P–N–P skeletons, respectively, have been used as versatile ligands,
Transition metal catalyzed procedures for the transfer hydroge-
nation of a wide variety of functional groups by different hydrogen
donors are an interesting alternative to conventional catalytic
hydrogenation [1,2]. In transfer hydrogenation, organic molecules
such as primary and secondary alcohols [3] or formic acid and its
salts [4] have been employed as the hydrogen source. The use of
a hydrogen donor has some advantages over the use of molecular
hydrogen since it avoids risks and 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 equilibriums and can be converted back to 2-propanol
by catalytic hydrogenation [5].
and varying the substituents on both the P- and N-centers gives
rise to changes in the P–N–P angle and the conformation around
the P-centers [6]. Small variations in these ligands can cause signif-
icant changes in their coordination behavior and the structural fea-
tures of the resulting complexes [7]. The complexes incorporating
this ligand type are of considerable interest due to their potential
use in many processes such as reductive elimination and oxidative
addition for making and breaking C–H bonds [8], formation and
cleavage of N–H and O–H bonds [9]. Also their extensive use in
classical catalytic processes such as allylic alkylation [10,11], Heck
[12,13], Suzuki [14,15], hydrogenation [16,17], isomerisation,
decarbonylation, etc. [18,19] cannot be ignored.
By choosing an appropriate ligand system, it is possible to fine
tune the electronic and steric properties of the donor centers to
bind to metals in the desired oxidation state with a specific coordi-
nation number so that a catalyst may be generated for a specific or-
ganic transformation. In this context, aminophosphines and
bis(phosphino)amines play a major role because of the easy and
⇑
Corresponding author. Tel.: +90 412 248 8550x3028; fax: +90 412 248 8300.
E-mail address: cezmik@dicle.edu.tr (C. Kayan).
0277-5387/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.poly.2012.05.009

C. Kayan et al. / Polyhedron 42 (2012) 142–148
143
high yield synthetic methodologies, and the flexibility in their
reactivity toward transition metals in various oxidation states
[20,21]. As a part of our interest in this area [22–24], the above
considerations prompted us to study a research program on ami-
nophosphine and bis(phosphino)amine complexes. We report here
the syntheses of a ruthenium complex of [(Ph2P)2NCH2-C4H3O] (1)
and ruthenium, rhodium and iridium complexes of [Ph2PNHCH2-
C4H3O] (2). All the complexes were isolated from the reaction
solution and fully characterized by analytical and spectroscopic
methods. The X-ray crystal structure of [Ru(Ph2PNHCH2-
chloride) that formed was filtered off under argon, and the solvent
was removed under reduced pressure. The residue was then
washed with cold diethyl ether (2 ꢁ 10 mL) and dried in vacuo to
produce a clear, white viscous oily compound, 1 (yield: 0.261 g,
91.1%). 1H NMR (d in ppm rel. to TMS, J in Hz, CDCl3): 7.37–7.44
(o-protons of phenyls, 8H), 7.28–7.33 (m, m and p-protons of phen-
yls, 12H), 7.13 (br, H-5, 1H), 6.11 (br, H-4, 1H), 5.48 (br, H-3, 1H),
4.34 (t, –CH2–, 2H, 3J = 8.6); 13C NMR (d in ppm rel. to TMS, J in
Hz, CDCl3): 153.50 (C-2), 141.34 (C-5), 139.02 (d, i-carbons of
phenyls, 1J(31P–13C) = 5.9), 132.76 (t, o-carbons of phenyls,
2J(31P–13C) = 11.1), 128.75 (s, p-carbons of phenyls), 128.10 (d, m-
carbons of phenyls, 3J(31P–13C) = 3.0), 110.28 (C-4), 108.24 (C-3),
47.83 (–CH2–); the assignment was based on 1H–13C HETCOR and
1H–1H COSY spectra; 31P NMR (d in ppm rel. to H3PO4, CDCl3):
C4H3O)(g
6-p-cymene)Cl2] (4) and pertinent features of this struc-
ture are also introduced. Furthermore, metal complexes of 1 and
2 were tested as catalysts in the transfer hydrogenation of a variety
of simple alkyl ketones.
62.54 (s); selected IR (KBr pellet, cmꢀ1):
m(P–N–P) 921, m(P–Ph)
1434. Anal. Calc. for C29H25ONP2 (mw: 465.5 g/mol); C, 74.83; H,
5.41; N, 3.01. Found: C, 74.72; H, 5.38; N, 3.00%.
2. Experimental (analytical)
2.1. NMR analyses
2.5.2. [Ph2PNHCH2-C4H3O] (2)
All 1H and 13C NMR measurements were performed in CDCl3
and recorded on a Bruker AV400 spectrometer. 1H NMR spectra
were collected at 400.1 MHz using a 8000 Hz spectral width, a
relaxation delay of 3.95 s, a pulse width of 30°, 30 k data points
and CDCl3 (7.27 ppm) as an internal reference. 13C NMR spectra
were collected at 100.6 MHz using a 24000 Hz spectra width, a
relaxation delay of 1.4 s, 75 k data points, a pulse width of 30°
and CDCl3 (77.23 ppm) as the internal reference. 31P NMR spectra
were collected at 162.0 MHz using a 65000 Hz spectra width, a
relaxation delay of 0.5 s, 150 k data points, a pulse width of 30°
and H3PO4 as the external reference.
Chlorodiphenylphosphine (0.4734 g, 2.04 mmol) was added to a
solution of furfurylamine (0.099 g, 1.02 mmol) and triethylamine
(0.200 g, 2.04 mmol) in thf (50 mL) at 0 °C with vigorous stirring.
The mixture was then stirred at room temperature for 2 h and
the white precipitate (triethylammonium chloride) that formed
was filtered off under argon and the solvent was removed under
reduced pressure. The residue was then washed with cold diethyl
ether (2 ꢁ 15 mL) and dried in vacuo to produce a yellow viscous
oily compound 2 [27] (yield: 0.215 g, 88.8%). 1H NMR (d in ppm
rel. to TMS, J in Hz, CDCl3): 7.45–7.48 (m, o-protons of phenyls,
4H), 7.36–7.41 (m, m- and p-protons of phenyls, 6H), 7.35 (d, H-
5, 1H, 3J = 2.0), 6.30 (dd, H-4, 1H, 3J = 2.0 and 3.2), 6.11 (d, H-3,
1H, 3J = 3.2), 4.01 (dd, –CH2–, 2H, 3J = 6.8 and 8.8), 2.38 (dt, –NH,
1H, J = 6.8 and 13.2); 13C NMR (d in ppm rel. to TMS, J in Hz, CDCl3):
43.09 (–CH2–), 106.27 (C-3), 110.26 (C-4), 141.71 (d, C-5), 128.30
(d, m-carbons of phenyls, 3J(31P–13C) = 6.3), 128.58 (s, p-carbons
of phenyls), 131.44 (d, o-carbons of phenyls, 2J(31P–13C) = 19.0),
140.95 (d, i-carbons of phenyls, 1J(31P–13C) = 12.1), 154.95 (d, C-2,
3J(31P–13C) = 6.0), assignment was based on 1H–13C HETCOR, DEPT
and 1H–1H COSY spectra; 31P NMR (d in ppm rel. to H3PO4, CDCl3):
2.2. Melting points
Melting point determinations were performed on samples using
a Gallenkamp model apparatus (SANYO Biomedical Equipment)
with a ramp rate of 5 °C/min.
2.3. Fourier-Transform Infrared Spectroscopy (FTIR)
42.71 (s); IR (KBr, cmꢀ1):
m(P–N) 804, m(P–Ph) 1434, m(N–H) 3383.
Fourier transform (FTIR) spectra were recorded on an ATI UNI-
CAM Mattson 1000 FTIR spectrometer (ATI-UNICAM Inc.,). Optical
grade, random cuttings of KBr (International Crystal Laboratories,
Garfield, NJ) were ground, with 1.0 wt% of the sample to be ana-
lyzed for FTIR analysis.
Anal. Calc. C17H16ONP (281.3 g/mol): C, 72.59; H, 5.73; N, 4.98.
Found: C, 72.49; H, 5.64; N, 4.95%.
2.5.3. trans-[Ru((PPh2)2NCH2-C4H3O)2Cl2] (3)
To
a
solution of [Ru(g l-Cl)Cl]2 (71 mg,
6-p-cymene)(
0.115 mmol) in 10 mL thf, a solution (thf, 30 mL) of (PPh2)2NCH2-
C4H3O (1) (215 mg, 0.462 mmol) was added. The resulting reaction
mixture was stirred at room temperature for 1 h. After this time,
the solution was filtered off and the solvent evaporated under vac-
uum, the solid residue thus obtained was washed with diethyl
ether (3 ꢁ 15 mL) and then dried under vacuum. Following recrys-
tallization from diethyl ether/CH2Cl2, a scarlet crystalline powder
was obtained (yield 114 mg, 89.1%). M.p. 298–299 °C; 1H NMR (d
in ppm rel. to TMS, J in Hz, CDCl3) 7.45–7.47 (br, o-protons of phen-
yls, 16H), 7.28–7.32 (t, m-protons of phenyls, 16H, 4J = 7.40), 7.06–
7.14 (dd, p-protons of phenyls, 8H, 5J = 7.3 and 8.6), 7.00 (b, H-5,
2H), 6.05 (br, H-4, 2H), 5.74 (d, H-3, 2H, 3J = 2.8), 4.44 (br, –CH2–,
4H); 13C NMR (d in ppm rel. to TMS, J in Hz, CDCl3): 45.93
(–CH2–), 141.30 (C-5), 110.38 (C-4), 126.73 (m-carbons of phenyls),
109.29 (C-3), 129.49 (p-carbons of phenyls), 134.78 (o-carbons of
phenyls), 133.91 (i-carbons of phenyls), 151.29 (C-2); assignment
was based on 1H–13C HETCOR and 1H–1H COSY spectra; 31P NMR
2.4. Materials
Unless otherwise stated, all reactions were carried out under ar-
gon using Schlenk glassware. Solvents were dried using established
procedures and distilled under argon immediately prior to use.
Analytical grade and deuterated solvents were purchased from
Merck. PPh2Cl, [Ru(
Cl)Cl]2 and furfurylamine were purchased from Fluka and were
used as received. The starting materials, Rh( -Cl)(cod)]2 and
[Ir( -Cl)Cl]2 were synthesized according to the re-
5-C5Me5)(
g l-Cl)Cl]2, [Ru(g l-
6-p-cymene)( 6-benzene)(
l
g
l
ported procedures [25,26].
2.5. Synthesis
2.5.1. [(Ph2P)2NCH2-C4H3O] (1)
Chlorodiphenylphosphine (0.237 g, 1.02 mmol) was added
dropwise over a period of 15 min to a stirred solution of furfuryl-
amine (0.099 g, 1.02 mmol) and triethylamine (0.104 g, 1.02 mmol)
in thf (40 mL) at 0 °C. The mixture was then stirred at room temper-
ature for 1 h and the white precipitate (triethylammonium
(d in ppm rel. to H3PO4, CDCl3): 78.93 (s); IR (KBr, cmꢀ1):
P) 924, (P–Ph) 1434. Anal. Calc. for C58H50N2O2P4RuCl2
m(P–N–
m
(1102.9 g/mol): C, 63.16; H, 4.57; N, 2.54. Found: C, 62.97; H,
4.43; N, 2.47%.

144
C. Kayan et al. / Polyhedron 42 (2012) 142–148
2.5.4. [Ru(Ph2PNHCH2-C4H3O)(
g
6-p-cymene)Cl2] (4)
6-p-cymene)(
-Cl)Cl]2 (0.312 g, 0.51
CH of cod, 2H), 4.22 (m, NH, 1H), 3.77 (br, –CH2–, 2H), 2.94 (br,
To a solution of [Ru(
g
l
CH of cod, 2H), 2.30 (m, CH2 of cod, 4H), 1.95 (br, CH2 of cod,
4H); 13C NMR (d in ppm rel. to TMS, J in Hz, CDCl3): 28.57 (CH2
of cod, (a)), 32.85 (d, CH2 of cod, (b), 2J = 5.0), 40.28 (d, –CH2–,
2J = 10.1), 70.94 (d, CH of cod, (a), 1J = 4.0), 105.21 (d, CH of cod,
(b), 1J = 6.0), 106.76 (C-3), 110.20 (C-4), 141.78 (C-5), 128.33 (d,
m-carbons of phenyls, 3J = 10.1), 130.62 (d, p-carbons of phenyls,
4J = 2.0), 133.36 (d, o-carbons of phenyls, 2J = 12.1), 132.26 (d, i-car-
bons of phenyls, 1J = 45.3), 153.01 (d, C-2, 3J = 8.1); assignment was
based on 1H–13C HETCOR, DEPT and 1H–1H COSY spectra; 31P-{1H}
NMR (d in ppm rel. to H3PO4, CDCl3): 61.57 (d, 1J
mmol) in tetrahydrofuran, a solution (thf, 30 mL) of [Ph2PNHCH2-
C4H3O] (2) 0.287 g, 1.02 mmol) was added. The resulting reaction
mixture was stirred at room temperature for 1 h. After this time,
the solution was filtered and the solvent evaporated under vac-
uum, the solid residue thus obtained was washed with diethyl
ether (3 ꢁ 10 mL) and then dried under vacuum. Following recrys-
talization from diethylether/CH2Cl2, a red crystalline powder was
obtained (yield 0.560 g, 93.5%). M.p. 192–193 °C; 1H NMR (d in
ppm rel. to TMS, J in Hz, CDCl3): 7.93–7.97 (m, o-protons of phen-
yls, 4H), 7.42–7.59 (m, m- and p- protons of phenyls, 6H), 7.20 (br,
H-5, 1H), 6.16 (br, H-4, 1H), 6.01 (br, H-3, 1H), 5.27 (d, aromatic
protons of p-cymene, 2H, 3J = 5.3), 5.10 (d, aromatic protons of p-
cymene, 2H, 3J = 5.7), 3.61 (dt, NH, 1H, 3J = 6.4 and 13.0), 3.51
(dd, –CH2–, 2H, 3J = 6.6 and 7.3), 2.64 (m, –CH– of p-cymene, 1H),
1.97 (s, CH3–Ph of p-cymene, 3H), 0.86 (d, (CH3)2CHPh of p-cym-
ene, 6H, 3J = 6.8); 13C NMR (d in ppm rel. to TMS, J in Hz, CDCl3):
17.44 (CH3Ph of p-cymene), 21.32 ((CH3)2CHPh of p-cymene),
30.06 (–CH– of p-cymene), 40.08 (d, –CH2–, 2J = 10.1), 86.19,
91.08 (aromatic carbons of p-cymene), 94.08, 108.21 (quaternary
carbons of p-cymene), 106.71 (C-3), 110.14 (C-4), 141.43 (C-5),
128.14 (d, m-carbons of phenyls, 3J = 10.1), 130.77 (d, p-carbons
of phenyls, 4J = 2.0), 132.86 (d, o-carbons of phenyls, 2J = 11.1),
133.95 (d, i-carbons of phenyls, 1J = 51.3), 152.96 (d, C-2, 3J = 6.0);
assignment was based on 1H–13C HETCOR, DEPT and 1H–1H COSY
spectra; 31P NMR (d in ppm rel. to H3PO4, CDCl3): 60.98 (s); IR
(
m
103Rh–31P) = 157.1); IR (KBr, cmꢀ1):
(P–Ph) 1436. Anal. Calc. for C25H28NOPRhCl (527.8 g/mol): C,
56.89; H, 5.34; N, 2.65. Found: C, 56.82; H, 5.31; N, 2.61%.
m(N–H) 3454, m(P–N) 1011,
2.5.7. [Ir(Ph2PNHCH2-C4H3O)(
g
5-C5Me5)Cl2] (7)
5-C5Me5)(
-Cl)Cl]2 (0.414 g, 0.51 mmol) and
A mixture of [Ir(
g
l
[Ph2PNHCH2-C4H3O] (0.287 g, 1.02 mmol) in 15 mL of tetrahydro-
furan was stirred at room temperature for 3 h. The volume of the
solvent was then reduced to 0.5 mL before addition of diethyl ether
(10 mL). The precipitated product was filtered and dried in vacuo,
yielding 7 as an orange microcrystalline solid (yield 0.630 g,
91.0%). M.p. 196.5–198.5 °C; 1H NMR (d in ppm rel. to TMS, J in
Hz, CDCl3) 7.87–7.93 (m, o-protons of phenyls, 4H), 7.46–7.47
(m, m- and p- protons of phenyls, 6H), 7.21 (d, H-5, 1H, 3J = 1.7),
6.18 (dd, 1H, H-4 3J = 1.7 and 3J = 2.9), 6.12 (d, H-3, 1H, 3J = 2.8),
3.85 (m, NH, 1H), 3.74 (dd, –CH2–, 2H, 3J = 7.0 and 7.2), 1.41 (d,
CH3 of Cp⁄ (C5Me5), 15H, 4J = 2.1); 13C NMR (d in ppm rel. to TMS,
J in Hz, CDCl3): 8.24 (C5Me5), 40.79 (d, –CH2–, 2J = 8.1), 92.36 (d,
C5Me5, 2J = 12.0), 106.59 (C-3), 110.19 (C-4), 141.36 (C-5), 127.91
(d, m-carbons of phenyls, 3J = 11.1), 130.84 (d, p-carbons of phen-
yls, 4J = 3.0), 131.33 (d, i-carbons of phenyls, 1J = 61.4), 133.41 (d,
o-carbons of phenyls, 2J = 11.1), 153.31 (d, C-2, 3J = 7.0); assign-
ment was based on 1H–13C HETCOR, DEPT and 1H–1H COSY spec-
tra; 31P-{1H} NMR (d in ppm rel. to H3PO4, CDCl3): 34.33 (s); IR
(KBr, cmꢀ1):
m(P–N) 845, m(P–Ph) 1433, m(N–H) 3375. Anal. Calc.
for C27H30NPORuCl2 (587.5 g/mol): C, 55.20; H, 5.15; N, 2.38.
Found: C, 55.01; H, 5.11; N, 2.35%.
2.5.5. [Ru(Ph2PNHCH2-C4H3O)(
g
6-benzene)Cl2] (5)
-Cl)Cl]2 (0.255 g, 0.51 mmol)
A mixture of [Ru(
g
6-benzene)(
l
and [Ph2PNHCH2-C4H3O] (0.287 g, 1.02 mmol) in 15 mL of tetrahy-
drofuran was stirred at room temperature for 2 h. The volume of
the solvent was then reduced to 0.5 mL before addition of diethyl
ether (10 mL). The precipitated product was filtered and dried in
vacuo, yielding 5 as a red microcrystalline powder. (yield 0.510 g,
94.1%). M.p. 180 °C (dec.); 1H NMR (d in ppm rel. to TMS, J in Hz,
CDCl3): 7.91–7.97 (m, o-protons of phenyls, 4H), 7.51–7.52 (m,
m- and p- protons of phenyls, 6H), 7.22 (d, H-5, 1H, 3J = 1.8), 6.17
(dd, H-4, 1H, 3J = 1.8 and 3.1), 6.02 (d, H-3, 1H, 3J = 3.1), 5.41 (s, aro-
matic protons of benzene, 6H), 3.68 (dd, –CH2–, 2H, 3J = 7.6 and
7.8), 3.55 (m, NH, 1H); 13C NMR (d in ppm rel. to TMS, J in Hz,
CDCl3): 40.20 (d, –CH2–, 2J = 9.1), 88.8 (d, aromatic carbons of ben-
zene, 2J = 4.0), 106.92 (C-3), 110.18 (C-4), 141.61 (C-5), 128.38 (d,
m-carbons of phenyls, 3J = 11.1), 131.02 (d, p-carbons of phenyls,
4J = 3.0), 132.67 (d, o-carbons of phenyls, 2J = 11.1), 133.92 (d, i-car-
bons of phenyls, 1J = 54.3), 152.70 (d, C-2, 3J = 7.0); assignment was
based on 1H–13C HETCOR, DEPT and 1H–1H COSY spectra; 31P–{1H}
(KBr, cmꢀ1):
m(N–H) 3338, m(P–N) 885, m(P–Ph) 1436. Anal. Calc.
for C27H31NOPIrCl2 (679.6 g/mol): C, 47.72; H, 4.60; N, 2.06. Found:
C, 47.68; H, 4.55; N, 2.04%.
2.6. GC analyses and general procedure for the transfer hydrogenation
of ketones
GC analyses were performed on a Shimadzu GC 2010 Plus Gas
Chromatograph equipped with a capillary column (5% biphenyl,
95% dimethylsiloxane) (30 m ꢁ 0.32 mm ꢁ 0.25
lm). The GC
parameters for transfer hydrogenation of ketones were as follows:
initial temperature, 110 °C; initial time, 1 min; solvent delay,
4.48 min; temperature ramp 80 °C/min; final temperature,
200 °C; final time, 21.13 min; injector port temperature, 200 °C;
detector temperature, 200 °C, injection volume, 2.0
procedure for the catalytic hydrogen transfer reaction: a solution
of the complex trans-[Ru((PPh2)2NCH2-C4H3O)2Cl2] (3),
[Ru(Ph2PNHCH2-C4H3O)(
6-p-cymene)Cl2] (4), [Ru(Ph2PNHCH2-
C4H3O)(
6-benzene)Cl2] (5), [Rh(Ph2PNHCH2-C4H3O)(cod)Cl] (6)
or [Ir(Ph2PNHCH2-C4H3O)(
5-C5Me5)Cl2] (7) (0.005 mmol), KOH
lL. Typical
NMR (d in ppm rel. to H3PO4, CDCl3): 61.63 (s); IR (KBr, cmꢀ1):
N) 916, (P–Ph) 1433, (N–H) 3334. Anal. Calc. for C23H22NPORuCl2
m(P–
m
m
(531.4 g/mol): C, 51.98; H, 4.17; N, 2.64. Found: C, 51.85; H, 4.14;
N, 2.61%.
g
g
g
2.5.6. [Rh(Ph2PNHCH2-C4H3O)(cod)Cl] (6)
(0.025 mmol) and cyclohexanone (0.5 mmol) in degassed iso-PrOH
(5 mL) were refluxed for 1 h for 3, 45 min for 4, 20 min for 5, 2 h for
6 and 4 h for 7. After this period a sample of the reaction mixture
was taken off, diluted with acetone and analyzed immediately by
GC. The conversions obtained are related to the residual unreacted
ketone.
A
mixture of [Rh(l-Cl)(cod)]2 (0.252 g, 0.51 mmol) and
[Ph2PNHCH2-C4H3O] (0.287 g, 1.02 mmol) in 15 mL of tetrahydro-
furan was stirred at room temperature for 3 h. The volume of the
solvent was then reduced to 0.5 mL before addition of diethyl ether
(10 mL). The precipitated product was filtered and dried in vacuo
yielding
6 as a yellow microcrystalline solid (yield 0.420 g,
88.8%). M.p. 118–120 °C; 1H NMR (d in ppm rel. to TMS, J in Hz,
CDCl3): 7.83–7.87 (m, o-protons of phenyls, 4H), 7.44–7.51 (m,
m- and p- protons of phenyls, 6H), 7.30 (d, H-5, 1H, 3J = 1.9), 6.24
(dd, H-4,1H, 3J = 1.9 and 2.1), 6.10 (d, H-3, 1H, 3J = 2.8), 5.56 (br,
2.7. X-ray crystallography
For the crystal structure determination, a single-crystal of com-
plex 4 was used for data collection on a four-circle Rigaku R-AXIS

C. Kayan et al. / Polyhedron 42 (2012) 142–148
145
methylene group gives a triplet at 4.34 ppm (3J = 8.6 Hz) for 1. Fur-
Table 1
Crystallographic data for the complex [Ru(Ph2PNHCH2-C4H3O)(g
6-p-cymene)Cl2], 4.
thermore, characteristic J
coupling constants of the carbons
31P—13
C
of the phenyl rings are observed in the 13C NMR spectrum (for de-
tails see Section 2), which are consistent with the literature values
[40,41].
Compound
4
C
Chemical formula
Formula weight
Crystal system
T (K)
Space group
a (Å)
27H30NOCl2PRu
587.46
monoclinic
293(2)
We examined some simple coordination chemistry of 1 with the
[Ru(g l-Cl)Cl]2 precursor. The reaction between the
6-p-cymene)(
P21/n
Ru(II) precursor and the bis(phosphino)amine 1 is profoundly af-
12.0583(4)
13.5970(7)
15.8247(6)
90.00
90.32(3)
90.00
2594.5(2)
4
53190
5322
4323
fected by the molar ratio of the reactants. The reaction of
b (Å)
c (Å)
(PPh2)2NCH2-C4H3O (1) with [Ru(g l-Cl)Cl]2 in thf in
6-p-cymene)(
a
(°)
a molar ratio of 1:1/4 at room temperature for 1 h yielded trans-
[Ru((PPh2)2NCH2-C4H3O)2Cl2] (3) as a crystalline ochre powder
(Scheme 1). Complex 3 was isolated and characterized by observ-
ing a singlet at 78.93 ppm in the 31P–{1H} NMR spectrum, in line
with the values previously observed for similar compounds
[29,42], which implies that (PPh2)2NCH2-C4H3O is acting as a
bidendate chelating ligand. The IR bands observed at 924 and
b (°)
c
(°)
V (Å3)
Z
Reflections collected
Independent reflections
Observed data
Unique data (Rint
)
0.089
1434 cmꢀ1 represent
m(PNP) and m
(PPh), respectively. The 13C
Dcalc (g cmꢀ3
)
1.504
Absorption coefficient (mmꢀ1
F(000)/GOOF
)
0.892
NMR spectrum gave signals in line with similar structures.
1200/1.142
0.14 ꢁ 0.14 ꢁ 0.10
2.1–26.5
Furfuryl-2-(N-diphenylphosphino)amine, [Ph2PNHCH2-C4H3O]
(2) was prepared by treating furfurylamine with one equivalent
of PPh2Cl [30,44]. The 31P–{1H} NMR spectrum of 2 showed a single
resonance at 42.71 ppm, similar to those found for closely related
compounds [45,46]. Complex 2 is unstable and decomposes rapidly
on exposure to air or moisture. Complex 2 was fully characterized
by multinuclear NMR, infrared spectroscopy and microanalysis. In
the 1H NMR spectrum, the NH resonance of 2 was observed as a
slightly broad pseudo-triplet or doublet of triplets at 2.38 ppm
Crystal size (mm)
h range for data collection (°)
R indices (all data)
R1 = 0.062, wR2 = 0.130
R1 = 0.043, wR2 = 0.111
0.608 and ꢀ0.969
Final R indices [I > 2
r(I)]
Largest difference in peak and hole (e Åꢀ3
)
RAPID-S diffractometer (equipped with a two-dimensional area IP
detector). The graphite-monochromatized Mo radiation
(k = 0.71073 Å) and the oscillation scans technique with = 5°
K
a
3
2
due to the multiple coupling, J(CHNH) and J(NHP), which was con-
firmed by a H/D exchange experiment. On carrying out the H/D ex-
change experiment, the NH signal simply disappears from the
spectrum, or more commonly is replaced by a weak signal close
to d 4.80 coming from suspended droplets of HDO.
D
x
for one image were used for data collection. The lattice parameters
were determined by the least-squares methods on the basis of all
reflections with F2 > 2 (F2). H atoms were positioned geometrically
r
and refined using a riding model. Integration of the intensities, cor-
rection for Lorentz and polarization effects, and cell refinement
were performed using CrystalClear (Rigaku/MSC Inc., 2005) soft-
ware.1 The structure was solved by direct methods using SHELXS-97
and refined by a full-matrix least-squares procedure using the pro-
gram SHELXL-97.2 The final difference Fourier maps showed no peaks
of chemical significance. Details of the crystal parameters, data col-
lection and refinement are summarized in Table 1.
The ability of the dimer {[Ru(
mononuclear complexes of the general formula [Ru(
ne)Cl2L] is well-known [47]. As expected, the reaction of [Ru(g6
p-cymene)( -Cl)Cl]2 and [Ph2PNHCH2-C4H3O], (2) gives
[Ru(Ph2PNHCH2-C4H3O)(
6-p-cymene)Cl2] (4) in high yield, which
g
6-p-cymene)(
l
-Cl)Cl]2} to form
g
6-p-cyme-
-
l
g
is an air stable, red microcrystalline powder (Scheme 1). The 31P–
{1H} NMR spectrum of 4 shows a single resonance at 60.98 ppm,
in line with the values previously observed for similar compounds
[48]. The 1H NMR spectrum of 4 exhibits multiplet signals at 7.93–
7.42 ppm corresponding to the aromatic rings. There exist two sig-
nals at 2.64 and 0.86 ppm due to CH and CH3 of the isopropyl
groups of the p-cymene moiety. In addition, a signal due to methyl
in the p-cymene group is observed at 1.97 ppm. Another set of sig-
nals consisting of two doublets centered at 5.27 and 5.10 ppm are
due to the presence of the aromatic protons in the p-cymene group
(the presence of one (broad) or two signals corresponding to CH p-
cymene protons in the 1H NMR spectrum is consistent with a Cs
symmetry of complex and with free rotation of the arene ring)
[49,50]. Furthermore in the 13C NMR spectrum of 4, the signals at
86.19, 91.08 (aromatic carbons of p-cymene) and 94.08,
108.21 ppm (quaternary carbons of p-cymene), correspond to car-
bons in the p-cymene ring (for further information, see Ref. [29]).
3. Results and discussion
3.1. Synthesis and characterization of the complexes
Although aminolysis of chlorophosphines is an efficient method
for preparing R2PN(H)R0 or (R2P)2NR0, it has not widely been
exploited yet, in part possibly because of the associated instability
of the P–N bonds in these ligands [29,30]. Furfuryl-2-(N,N-
bis(diphenylphosphino)amine) (1) was prepared from the com-
mercially available starting materials furfurylamine and two
equivalents of Ph2PCl in the presence of triethylamine by aminoly-
sis [32–35] in thf at 0 °C (Scheme 1). Complex 1 was fully charac-
terized by multinuclear NMR, infrared spectroscopy and
microanalysis. All the compounds gave reasonable microanalysis
results. The 31P–{1H} NMR spectrum of 1 showed a single reso-
nance at 62.54 ppm, similar to those found for closely related com-
pounds [36]. Complex 1 is not stable and decomposes rapidly on
exposure to air or moisture. When the reaction was monitored
by 31P–{1H} NMR spectroscopy, the formation of P(O)Ph2PPh2
was observed, as indicated by signals at 35.20 (d) and ꢀ25.10 (d)
ppm, {1J(PP) = 224 Hz} [37–39]. In the 1H NMR spectrum, the
Some simple coordination chemistry of 2 with the [Ru(
zene)( -Cl)Cl]2 precursor was investigated as well. The resulting
g
6-ben-
l
complex 5 is highly soluble in CH2Cl2 but only slightly soluble in
hexane, so it can be crystallized from a CH2Cl2/hexane solution.
The chemical purity of complex 5 was confirmed by the presence
of a single 31P–{1H} NMR signal at 61.63 ppm. The 1H NMR spec-
trum of complex 5 displays a singlet at 5.41 ppm for the C6H6 pro-
tons and a doublet of doublets at 3.68 ppm (3J = 7.6 and 7.8 Hz) for
the CH2 protons. In the 13C–{1H} NMR spectrum of 5, the C6H6 car-
bon signal was observed at 88.78 ppm (d, 2J = 4.0 Hz) and the CH2
carbon resonance was seen at 40.20 ppm (d, 2J = 9.1 Hz). The
1
Rigaku/MSC, Inc., 9009 New Trails Drive, The Woodlands, TX 77381, USA.
G.M. Sheldrick, SHELXS97 and SHELXL97, University of Göttingen, Germany, 1997.
2

146
C. Kayan et al. / Polyhedron 42 (2012) 142–148
Scheme 1. Synthesis of the ligands (PPh2)2NCH2-C4H3O (1) and [Ph2PNHCH2-C4H3O] (2), and the complexes trans-[Ru((PPh2)2NCH2-C4H3O)2Cl2] (3), [Ru(Ph2PNHCH2-
C4H3O)(
g
6-p-cymene)Cl2] (4), [Ru(Ph2PNHCH2-C4H3O)(
g
6-benzene)Cl2] (5), [Rh(Ph2PNHCH2-C4H3O)(cod)Cl] (6) and [Ir(Ph2PNHCH2-C4H3O)(
g
5-C5Me5)Cl2] (7). (i) 2 equiv.
6-p-cymene)(
l-Cl)Cl]2; (iv) 1/2 equiv. [Ru(
g l-Cl)Cl]2 thf; (v) 1/2 equiv.
6-p-cymene)(
1
Ph2PCl, 2 equiv. Et3N, thf; (ii) 1 equiv. Ph2PCl, 1 equiv. Et3N, thf; (iii)
equiv. [Ru(
g
4
[Ru( -Cl)Cl]2, thf; (vi) 1/2 equiv. [Rh(
g
6-benzene)(
l
l-Cl)(cod)]2, thf; (vii) 1/2 equiv. [Ir(
g
5-C5Me5)(
l-Cl)Cl]2, thf.
Table 2
Selected bond lengths (Å), bond and torsion angles (°) for the structure of 4.
Bond lengths
Ru–Cl(1)
Ru–C(7)
Ru–P(1)
P(1)–C(11)
O(1)–C(24)
N(1)–C(23)
Ru–Cl(2)
2.415(2)
2.205(2)
2.344(2)
1.835(5)
1.368(6)
1.440(6)
2.412(2)
2.206(4)
1.652(4)
1.816(4)
1.385(7)
Ru–C(4)
P(1)–N(1)
P(1)–C(17)
O(1)–C(27)
Bond angles
Ru–P(1)–N(1)
Ru–P(1)–C(17)
N(1)–P(1)–C(17)
Ru–P(1)–C(11)
N(1)–P(1)–C(11)
C(11)–P(1)–C(17)
Ru–P(1)–N(1)–C(23)
Ru–P(1)–C(11)–C(16)
Ru–P(1)–C(17)–C(18)
C(17)–P(1)–N(1)–C(23)
110.6(2)
114.0(2)
105.5(2)
117.1(2)
106.5(2)
102.2(2)
ꢀ178.2
164.0
Ru–P(1)–C(11)–C(12)
Ru–P(1)–C(17)–C(22)
N(1)–P(1)–C(17)–C(18)
N(1)–P(1)–C(17)–C(22)
ꢀ20.3
92.3
156.5
ꢀ29.3
ꢀ81.9
ꢀ54.4
Fig. 1. The molecular structure of [Ru(Ph2PNHCH2-C4H3O)(g
6-p-cymene)Cl2] (4).
Displacement ellipsoids are drawn at the 40% probability level.
Next we investigated some simple coordination chemistry of
structural composition of complex 5 was further confirmed by IR
spectroscopy and microanalysis, and was found to be in good
agreement with the theoretical values.
[Ph2PNHCH2-C4H3O] (2) with [Rh(
C5Me5)( -Cl)Cl]2 precursors. The reactions of
Cl)(cod)]2 and [Ir(
5-C5Me5)(
l
-Cl)(cod)]2 and [Ir(g5
with Rh(
-
-
l
2
l
g
l
-Cl)Cl]2 in tetrahydrofuran in a ratio

C. Kayan et al. / Polyhedron 42 (2012) 142–148
147
Scheme 2. Transfer hydrogenation reaction for simple ketones.
Table 3
Transfer hydrogenation of various simple ketones with iso-PrOH catalyzed by trans-[Ru((PPh2)2NCH2-C4H3O)2Cl2] (3), [Ru(Ph2PNHCH2-C4H3O)(
g
6-p-cymene)Cl2] (4),
Ru(Ph2PNHCH2-C4H3O)(
g
6-benzene)Cl2] (5), [Rh(Ph2PNHCH2-C4H3O)(cod)Cl] (6) and [Ir(Ph2PNHCH2-C4H3O)(
g
5-C5Me5)Cl2], (7).[a]
Conversation[b]
CAT
Substrate
Product
Time
TOF[c] (hꢀ1
)
3
4
5
6
7
1 h
98
97
98
97
98
98
129
294
49
O
OH
45 min
20 min
2 h
4 h
25
3
4
5
6
7
1 h
99
98
98
98
99
99
131
294
49
O
OH
45 min
20 min
2 h
4 h
25
3
4
5
6
7
3 h
2 h
1.5 h
4 h
6 h
99
98
98
97
97
33
49
65
24
16
O
OH
3
4
5
6
7
6 h
4 h
3 h
9 h
13 h
99
98
98
99
98
17
25
33
11
8
O
OH
Reaction conditions: [a]Refluxing in iso-PrOH; acetophenone/Ru/NaOH, 100:1:5; [b]Determined by GC (three independent catalytic experiments); [c]Referred at the reaction
time indicated in column; TOF = (mol product/mol Ru(II)Cat.) ꢁ hꢀ1
.
of 1:1/2 at room temperature for 3 h gave micro-crystalline precip-
itates of the neutral complexes 6 and 7, respectively, in good yield.
The 31P–{1H} NMR spectrum of 6 shows a doublet centered at
61.57 ppm with J(P–Rh) = 157.1 Hz [51,52]. The 1H NMR spectrum
6 displays three broad singlets at 5.56, 2.94 and 1.95 ppm and a
multiplet at 2.30 ppm for the cod protons. In the 31P–{1H} NMR
normal at 1.702(2) Å. No meaningful interactions between inde-
pendent complexes are observed in the crystal packing, and the
ClꢂꢂꢂH–C distances range from 3.584(4) to 3.627(4) Å. Selected bond
lengths and angles are presented in Table 2.
3.2. Catalytic transfer hydrogenation of ketones
spectrum of
[Ir(Ph2PNHCH2-C4H3O)(
7
a
singlet at 34.33 ppm was assigned to the
g
5-C5Me5)Cl2] complex, in line with the
The activity of Ru(II) arene complexes is well known in this cat-
alytic process [56,57]. In a preliminary study, 0.01 mmol of com-
plex 3 and 1 mmol of ketone were added to a solution of NaOH
in iso-PrOH (0.05 mmol of NaOH in 10 mL iso-PrOH) and refluxed
at 82 °C, the reaction being monitored by GC (Scheme 2). For alkyl
ketones, heating is generally required to achieve high conversion.
With a complex/NaOH ratio of 1/5, the complex is very active, lead-
ing to nearly quantitative transformation of cyclohexanone and
cyclopentanone in 1 h, with a moderate TOF of ꢃ100 hꢀ1 (Table 3),
whereas conversion of methyl isobutyl ketone and diethyl ketone
required longer times (3 and 6 h, respectively). It should be pointed
out that complex 3 is a more active catalyst than the corresponding
values previously observed for similar compounds [53]. The 1H
NMR spectrum of complex 7 is in accord with the proposed struc-
ture. In the 13C–{1H} NMR spectrum of 7, carbon signals at 8.24 and
92.36 ppm due to C5Me5 and C5Me5, respectively, were observed.
As part of the characterization of the complexes, we also report
herein the crystal structure of one representative example, namely
complex 4. Single crystals suitable for an X-ray diffraction study
were obtained by slow diffusion of diethyl ether into a solution
of the compound in dichloromethane over several days. The
single-crystal X-ray structure analysis of [Ru(Ph2PNHCH2-
C4H3O)(
g
6-p-cymene)Cl2] (4) reveals
a
g
typical piano-stool
6-coordinated by the
precursor: [Ru(g l-Cl)Cl]2 (41% maximum yield in
6-p-cymene)(
geometry with the ruthenium atom being
para-cymene ligand, along with two chlorides and a phosphine li-
gand with the substituted diphenyl and furan-2-yl-methylamine
(see Fig. 1). The Ru–P bond length [2.344 (3) Å] is about 0.17 Å
24 h) with a 1/14 complex/NaOH ratio [58].
We know that complexes with sp3-hybridized nitrogens and
containing N-H bonds exhibit high catalytic activity [59]. On the
other hand, the presence of an N–H group in the ligands possibly
stabilizes a seven membered ring, which is formed as a transient
by hydrogen bonding with the oxygen atom of the ketone [60–
63]. Considering the higher efficiency of complexes having N-H
bonding in Ru-mediated catalysis reactions, we prepared the furfu-
ryl-2-(N-diphenylphosphino)amine ligand and its Ru(II) complexes
4 and 5. Investigation of the catalytic activity of these complexes
shorter than the sum of the covalent Ru and
(1.46 + 1.05 = 2.51 Å), but is comparable to the value found in our
other arene–Ru–P complex, [Ru(Ph2PNHCH2-C4H3S)(
6-ben-
zene)Cl2] [2.328(1) Å] [54]. Similarly, the Ru–P bond distance
[2.344(3) Å] is comparable to that found in dichloro(
6-p-
P radii
g
g
cymene)(triphenylphosphine)-ruthenium(II) [2.3438(6) Å] [55].
The distance between Ru and the centroid of the arene ligand is

148
C. Kayan et al. / Polyhedron 42 (2012) 142–148
[15] M. Aydemir, F. Durap, A. Baysal, O. Akba, B. Gümgüm, S. Özkar, L.T. Yıldırım,
Polyhedron 28 (2009) 2313.
[16] R. Spogliarich, J. Kaspar, M. Graziani, J. Organomet. Chem. 306 (1986) 407.
[17] A.M. Maj, M. Pietrusiewicz, I. Suisse, F. Agbossou, A. Mortreux, Tetrahedron:
Asymmetry 10 (1999) 831.
[18] P.R. Hoffman, K.G. Caulton, J. Am. Chem. Soc. 97 (1975) 4221.
[19] M.S. Balakrishna, R. Panda, D.C. Smith Jr., A. Klaman, S.P. Nolan, J. Organomet.
Chem. 599 (2000) 159.
[20] R.J. Haines, M. Laing, E. Meintjies, P. Sommerville, J. Organomet. Chem. 215
(1981) 17.
has shown that they are efficient catalysts, affording almost a
quantitative transformation of the ketones in shorter times, and
5 is more active than 4 (Table 3). Complex 4 catalyzed transforma-
tions of cyclohexanone and cyclopentanone in 45 min, while 5 in-
duced the transformations in only 20 min. Consequently, the
catalytic activities of 4 and 5 were generally much higher in the
studied hydrogen transfer reactions than those of 3.
Ruthenium-based catalysts have usually been applied in the
hydrogenation of ketones [64–66], however rhodium or iridium
complexes have also been employed and have been found to be
efficient catalysts in several processes [67,68]. Consequently, we
also investigated the catalytic activity of the Rh and Ir complexes
of the furfuryl-2-(N-diphenylphosphino)amine ligand, complexes
6 and 7 respectively. However, their efficiency was lower, leading
to longer conversion times. For instance, hydrogenations of
cyclohexanone and cyclopentanone could be achieved in 2 and
4 h by [Rh(Ph2PNHCH2-C4H3O)(cod)Cl] (6) and [Ir(Ph2PNHCH2-
[21] M.S. Balakrishna, V.S.R. Reddy, S.S. Krishnamurthy, J.C.T.R. Burckette St
Laurent, J.F. Nixon, Coord. Chem. Rev. 129 (1994) 1.
[22] M.S. Balakrishna, S.S. Krishnamurthy, Inorg. Chim. Acta 230 (1995) 245.
[23] M.S. Balakrishna, B. Santarsiero, R.G. Cavel, Inorg. Chem. 33 (1994) 3079.
[24] M.S. Balakrishna, S.S. Krishnamurthy, R. Murugavel, M. Netaji, I.I. Mathews, J.
Chem. Soc., Dalton Trans. (1993) 477.
[25] G. Giordano, R.H. Crabtree, Inorg. Synth. 28 (1990) 88.
[26] C. White, A. Yates, P.M. Maitliss, Inorg. Synth. 29 (1992) 228.
[27] K. Song, H. Gao, F. Liu, J. Pan, L. Guo, S. Zai, Q. Wu, Eur. J. Inorg. Chem. (2009)
3016.
[29] K.G. Gaw, M.B. Smith, A.M.Z. Slawin, New J. Chem. 24 (2000) 429.
[30] A. Baysal, M. Aydemir, F. Durap, B. Gümgüm, S. Özkar, L.T. Yıldırım, Polyhedron
26 (2007) 3373.
[32] G. Ewart, A.P. Lane, J. McKechnie, D.S. Payne, J. Chem. Soc. A (1967) 1492.
[33] T. AppleBy, S.M. Aucott, M.L. Clarke, A.M.Z. Slawin, J.D. Woollins, Polyhedron
21 (2002) 2639.
[34] K.G. Gaw, M.B. Smith, J.W. Steed, J. Organomet. Chem. 664 (2002) 294.
[35] M.R.I. Zubiri, H.I. Milton, A.M.Z. Slawin, J.D. Woollins, Inorg. Chim. Acta 357
(2004) 1243.
C4H3O)(g
5-C5Me5)Cl2] (7), respectively. Conversion of methyl iso-
butyl ketone occurred in 4 and 6 h by 6 and 7, respectively, while
that of diethyl ketone occurred in 9 and 13 h, respectively.
4. Conclusions
[36] N. Biricik, F. Durap, B. Gümgüm, Transition Met. Chem. 32 (2007) 877.
[37] Z. Fei, R. Scopelliti, P.J. Dyson, Inorg. Chem. 42 (2003) 2125.
[38] Z. Fei, R. Scopelliti, P.J. Dyson, Eur. J. Inorg. Chem. (2004) 530.
[39] S. Berger, S. Braun, H.-O. Kolinowski, NMR-Spektroskopie von Nichtmetallen
Band 3, 31P NMR-Spektroskopie, Georg Theime Verlag, Stuttgart, New York,
1993.
[40] F. Majoumo, P. Lönnecke, O. Kühl, E. Hey-Hawkins, Z. Anorg. Allg. Chem. 630
(2004) 305.
[41] D. Morales-Morales, R. Redon, C. Yung, C.M. Jensen, Chem. Commun. (2000)
1619.
[42] L. Dahlenburg, C. Kühlein, Inorg. Chim. Acta. 361 (2008) 2785.
[44] M. Aydemir, A. Baysal, F. Durap, B. Gümgüm, S. Özkar, L.T. Yıldırım, Appl.
Organomet. Chem. 23 (2009) 467.
[45] A.D. Burrows, M.F. Mahon, M.T. Palmer, J. Chem. Soc., Dalton Trans. (2000)
1669.
[46] M. Aydemir, A. Baysal, G. Öztürk, B. Gümgüm, Appl. Organomet. Chem. 23
(2009) 108.
[47] H. Le Bozec, D. Touchard, P.H. Dixneuf, Adv. Organomet. Chem. 29 (1989) 163.
[48] A.M.Z. Slawin, J. Wheatley, J.D. Woollins, Eur. J. Inorg. Chem. (2005) 713.
[49] E. De la Encarnacion, J. Pons, R. Yanez, J. Ros, Inorg. Chim. Acta 358 (2005)
3272.
In summary, we have synthesized a bis(phosphino)amine li-
gand and its ruthenium complex, and an aminophosphine ligand
and some selected transition-metal (ruthenium, rhodium and
iridium) complexes with this aminophosphine ligand. All these
compounds were characterized using multinuclear NMR and IR
spectroscopy and microanalysis. One representative structure
was also studied by single crystal X-ray diffraction analysis. We
have found that complexes 3–7 are efficient homogeneous cata-
lytic systems that can be readily employed in the transfer hydroge-
nation of ketones to alcohols with high conversion. However, the
Ru(II)–benzene aminophosphine complex showed higher catalytic
activity in the transfer hydrogenation reaction than the analogous
Ru(II)–p-cymene, Rh(I)–cod and Ir(III)–Cp⁄ complexes and the
trans-Ru(II)–p-cymene bis(phosphino)amine complex.
[50] I. Moldes, E. De la Encarnacion, J. Ros, A. Alvarez-Larena, J.F. Piniella, J.
Organomet. Chem. 566 (1998) 165.
Appendix A. Supplementary data
[51] H.L. Milton, M.V. Wheatley, A.M.Z. Slawin, J.D. Woollins, Polyhedron 23 (2004)
3211.
[52] P. Bhattacharyya, T.Q. Ly, A.M.Z. Slawin, J.D. Woollins, Polyhedron 20 (2001)
1803.
[53] A.M.Z. Slawin, J. Wheatley, J.D. Woollins, Polyhedron 23 (2004) 2569.
[54] M. Aydemir, A. Baysal, N. Meric, C. Kayan, B. Gümgüm, S. Özkar, E. Sahin, J.
Organomet. Chem. 696 (2011) 2584.
[55] M.R.J. Elsegood, M.B. Smith, N.M. Sanchez-Ballester, Acta Crystallogr., Sect. E
62 (2006) m2838.
CCDC 852377 contains the supplementary crystallographic data
for 4. 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.
References
[56] R. Le Lagadec, L. Rubio, L. Alexandrova, R. Toscano, E.V. Ivanova, R. Meskys, V.
Laurinavicius, M. Pfeffer, A.D. Ryabov, J. Organomet. Chem. 689 (2004) 4820.
[57] A.D. Ryabov, V.S. Kurova, V. Ekaterina, R. Ivanova, R. Le Lagadec, L.
Alexandrova, Anal. Chem. 77 (2005) 1132.
[58] R. Tribo, S. Munoz, J. Pons, R. Yanez, A. Alvarez-Larena, J.F. Piniella, J. Ros, J.
Organomet. Chem. 690 (2005) 4072.
[1] H. Jiang, O.D. Qiao, H. Gong, React. Kinet. Catal. Lett. 65 (1) (1998) 193.
[2] R.A.W. Johnstone, A.H. Wilby, I.N. Entwistle, Chem. Rev. 85 (1985) 129.
[3] R. Noyori, M. Yamakawa, S. Hashiguchi, Acc. Chem. Res. 23 (1990) 345.
[4] S. Ram, R.E. Ehrenkaufer, Synthesis (1988) 91.
[59] M. Aydemir, A. Baysal, Polyhedron 29 (2010) 1219.
[60] J.-X. Gao, P.-P. Xu, X.-D. Yi, C.-B. Yang, H. Zhang, S.-H. Cheng, H.-L. Wan, K.-R.
Tsai, T. Ikariya, J. Mol. Catal. A: Chem. 147 (1999) 105.
[61] A.M. Maj, K.M. Pietrusiewicz, I. Suisse, F. Agbossou, A. Mortreux, J. Organomet.
Chem. 626 (2001) 157.
[62] M. Aydemir, F. Durap, A. Baysal, N. Meric, A. Bulda, B. Gümgüm, S. Özkar, L.T.
Yıldırım, J. Mol. Catal. A: Chem. 326 (2010) 75.
[63] M. Aydemir, A. Baysal, S. Özkar, L.T. Yıldırım, Inorg. Chim. Acta 367 (2011) 166.
[64] R. Noyori, T. Ohkuma, Angew. Chem., Int. Ed. Engl. 40 (2001) 40.
[65] J. Canivet, G. Labat, H. Stockli-Evans, G. Süss-Fink, Eur. J. Inorg. Chem. (2005)
4493.
[5] S. Özkar, R.G. Finke, J. Am. Chem. Soc. 127 (2005) 4800.
[6] H.-J. Chen, J.M. Barendt, R.C. Haltiwanger, T.G. Hill, A.D. Norman, Phosphorus,
Sulfur, Silicon and Relat. Elem. 26 (1986) 155.
[7] P. Bhattacharyya, J.D. Woollins, Polyhedron 14 (1995) 3367.
[8] S.D. Ittel, C.A. Tolman, A.D. English, J.P. Jesson, J. Am. Chem. Soc. 100 (1978)
7577.
[9] J.F. Hartwig, R.A. Anderson, R.G. Bergman, Organometallics 10 (1991) 1710.
[10] Y. Wang, X. Li, K. Ding, Tetrahedron Lett. 43 (2002) 159.
[11] N. Biricik, F. Durap, B. Gümgüm, Z. Fei, R. Scopelliti, Transition Met. Chem. 32
(7) (2007) 877.
[12] D.P. Catsoulocas, B.R. Steele, G.A. Herapoulos, M. Micha-Screttas, C.G. Screttas,
Tetrahedron Lett. 44 (2003) 4575.
[66] P. Stepnicka, J. Ludvíc, J. Canivet, G. Süss-Fink, Inorg. Chim. Acta 359 (2006)
2369.
[67] S.C. Stinson, Chem. Eng. News 77 (1999) 101.
[13] F. Durap, Ö. Metin, M. Aydemir, S. Özkar, Appl. Organomet. Chem. 23 (12)
(2009) 498.
[14] M.L. Clarke, D.J. Cole-Hamilton, J.D. Woollins, J. Chem. Soc., Dalton Trans.
(2001) 2721.
[68] H.-U. Blaser, F. Spindler, M. Studer, Appl. Catal. A 221 (2001) 119.