Synthesis, characterization and reactivity of arene ruthenium compounds based on 2,2′-dipyridylamine and di-2-pyridylbenzylamine and their applications in catalytic hydrogen transfer of ketones

Article abstract of DOI:10.1016/j.jorganchem.2010.06.003

The synthesis and characterization of cationic arene ruthenium compounds [(η⁶-p-ⁱPrC₆H₄Me) RuCl(κ²-dpa)]BF₄ (1), [(η⁶-C ₆H₆)RuCl(κ²-dpa)]BF₄

Full text of DOI:10.1016/j.jorganchem.2010.06.003

Journal of Organometallic Chemistry 695 (2010) 2205e2212
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis, characterization and reactivity of arene ruthenium compounds based
on 2,20-dipyridylamine and di-2-pyridylbenzylamine and their applications
in catalytic hydrogen transfer of ketones
Prashant Kumar a, Ashish Kumar Singh a, Rampal Pandeya, Pei-Zhou Li b, Sanjay Kumar Singh b,
,
Qiang Xu b, Daya Shankar Pandeya
*
a Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, U.P., India
b National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan
a r t i c l e i n f o
a b s t r a c t
The synthesis and characterization of cationic arene ruthenium compounds [(h -
6-p-iPrC6H4Me)RuCl(k2
Article history:
dpa)]BF4 (1), [(
h
6-C6H6)RuCl(
k
2-dpa)]BF4 (2), [(
h
6-p-iPrC6H4Me)-RuCl(
k
2-dpb)]BF4 (3), [(
h
6-p-iPrC6H4Me)
Received 14 May 2010
Received in revised form
2 June 2010
Accepted 6 June 2010
Available online 15 June 2010
RuCl(
k
2-dpb)]PF6.CH3OH (4) and [(
h
6-C6H6)-RuCl(
k
2-dpb)]PF6 (5) (arene ¼ C6H6 or p-iPrC6H4Me;
dpa ¼ 2,20-dipyridylamine and dpb ¼ di-2-pyridylbenzylamine) have been described. Reactions of the
representative compounds 1 and 3 with NaN3, NaCN, and NH4SCN afforded substitution products [(h6
-
p-iPrC6H4Me)-Ru(
2-dpa)(NCS)]BF4 (8), [(
(10) and [(
6-p-iPrC6H4Me)Ru(
k
2-dpa)(N3)]BF4 (6), [(
6-p-iPrC6H4Me)Ru(
2-dpb)(NCS)]BF4 (11). The compounds under investigation have been
h
6-p-iPrC6H4Me)Ru(
k
2-dpa)(CN)]BF4 (7), [(
h
6-p-iPrC6H4Me)-Ru
k
(
k
h
k
2-dpb)(N3)]BF4 (9), [(
h
6-p-iPrC6H4Me)-Ru(
2-dpb)(CN)]BF4
Keywords:
Ruthenium
2,20-Dipyridylamine
2,20-Dipyridylbenzylamine
Catalysis
h
k
characterized by elemental analyses, spectroscopic and electrochemical studies. Molecular structures of
1, 3, 4 and 5 have been determined crystallographically. The compounds 1e3 and 5 exhibited moderate
catalytic activity in the reduction of ketones into corresponding alcohol in absence of a base.
Ó 2010 Elsevier B.V. All rights reserved.
Aceto-phenone
Benzophenone
1. Introduction
rings of dpa adapt either nearly co-planar or inclined pyridyl ring
planes. This peculiar property of dpa and its derivatives induces
The coordination chemistry of dipyridylamine (dpa) and its
derivatives has now been the subject of a number of studies,
reflecting its coordination versatility and affinity for a range of
metal ions [1]. 2,20-Dipyridylamine, which is very similar to 2,20-
bipyridine has been widely employed in the synthesis of numerous
mono and polynuclear metal complexes [2]. In general, dpa
behaves as a bidentate chelating ligand in mononuclear complexes
bonded through both the terminal pyridine nitrogen donor sites.
However, depending upon requirements about the metal centre, it
also interacts in an unusual monodentate binding mode, selectively
via one of the terminal pyridine nitrogens [3]. A number of poly-
dentate ligands containing dipyridylamine as the fragment of
extended ligand system have also been developed and employed in
the studies ranging from metal coordination and supramolecular
chemistry to synthesis of new luminescent materials [4,5]. It is well
established that upon coordination with the metal centres pyridyl
either electronically or stereochemically in the systems and have
been observed in a number of metal complexes [6e9]. Further, the
amine proton of dpa becomes more acidic upon complexation to
the metal centre and both protonated as well as deprotonated
(dpaꢀ) complexes based on a number of metal ions have been
studied [10e12]. Loss of this proton is believed to result in planar
ligand configuration in the complexes [13]. Palladium (II) and
platinum (II) complexes of both the dpa and its extended deriva-
tives have also been investigated as potential anticancer agents due
to their structural similarity to cis-platin [14e16].
Furthermore, chloro-bridged dimeric arene ruthenium
complexes [{(
h
6-arene)Ru(
m
-Cl)Cl}2] (arene ¼ C6H6, p-iPrC6H4Me,)
plays a vital role in organometallic chemistry [17]. While reactivity
of these valuable precursors with a variety of ligands has been
reported, its reactivity with 2,20-dipyridylamine (dpa) and di-2-
pyridylbenzylamine (dpb) have not been explored. With an
objective of expanding the chemistry of dpa/dpb and to develop
hydrogen transfer catalysts containing both the (h
6-arene)Ru-
moieties and dpa/dpb, we have synthesized and characterized
a series of cationic ruthenium(II) compounds. In this paper we
* Corresponding author. Tel.: þ 91 542 6702480; fax: þ 91 542 2368174.
E-mail address: dspbhu@bhu.ac.in (D.S. Pandey).
0022-328X/$ e see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2010.06.003

2206
P. Kumar et al. / Journal of Organometallic Chemistry 695 (2010) 2205e2212
present the syntheses, spectral and structural characterization of
some piano-stool ruthenium(II) compounds containing dpa and
dpb as a co-ligands. Also, we describe herein catalytic applications
of 1e3 and 5 in reduction of acetophenone or benzophenone to
corresponding alcohol under basic conditions.
The 1H NMR spectral data of compounds summarized in
experimental section displayed resonances associated with pyridyl
and h
6-arene ring protons. The position and integrated intensity of
various resonances corroborated well to a system involving coor-
dination of respective ligands to the metal centre ruthenium. The
assignments are based on splitting patterns and chemical shifts and
comparison with the spectra of other d6 tris(bipyridine)
compounds [20]. In the spectra of uncoordinated ligand and the
compounds containing dpa, resonances corresponding to acidic
2. Result and discussion
2.1. Syntheses and characterization
amine proton were displayed as a well resolved signal at
d 4.00 and
The synthesis of cationic mononuclear arene ruthenium
wd 11.00 ppm, respectively with respect to aromatic protons. The
compounds of the general formulations [(
h
6-arene)RuCl2(L)]þ (where
loss of resonances associated with acidic amine proton of free
ligand in the compounds containing dpb is therefore, a strong
support in favour of proposed stoichiometry of the deprotonated
L ¼ dpa, and arene ¼ p-iPrC6H4Me, 1; C6H6, 2; L ¼ dpb, are-
ne ¼ p-iPrC6H4Me, 3; arene ¼ p-iPrC6H4Me, 4 isolated as PF6L; C6H6,
5) have been achieved by the reactions of chloro-bridged dimeric
products. The eCH2 protons resonated at d 5.55e5.29 (s, 2H, eCH2)
complexes [{(
h
6-arene)Ru(
m
-Cl)Cl}2] (arene ¼ C6H6 or p-iPrC6H4Me)
ppm in the spectra of compounds 3e5 and 9e11. Protons corre-
with 2,20-dipyridyl-amine (dpa) and di-2-pyridylbenzylamine (dpb)
in methanol under refluxing conditions. The compounds 1e3 and 5
have been isolated as tetrafluoroborate salts in good yields, while 4 as
its hexafluorophosphate salt. The representative compounds
sponding to the coordinated p-iPrC6H4Me (1, 3e4, 6e11) and C6H6
(2 and 5), resonated at d 1.10 {d, 6H, CH(CH3)2}, 2.24 (s, 3H, CeCH3),
2.40 {m, 1H,CH(CH3)2}, 5.30 (dd, 4H, C6H4), and 5.68 (s, 6H, C6H6)
ppm, respectively. One can see that the signals associated with
arene protons exhibited an insignificant shift. Substitution of the
Clꢀ by various monodentate ligands from precursor compounds 1
and 3 causes deshielding of various signals associated with dpa or
dpb and arene protons. It may be attributed to a change in the
electron density on metal centre resulting from the linkage of
displacing ligands.
Electronic absorption spectra of 1e10 were acquired in acetoni-
trile (10ꢀ4 M) at room temperature. Resulting data is summarized in
experimental section and comparative spectra of 1e10 are depicted
in Fig. S1. The metal centre ruthenium in these compounds have low
spin d6 configuration that provides filled t2g metal orbitals of proper
symmetry to interact with relatively low lying unoccupied p*
orbitals of the ligands dpa or dpb. Ruthenium(II) compounds con-
taining dipyridylamine usually exhibit intense peaks in the UV
[(h k h
6-p-iPrC6H4Me)RuCl( 2-dpa)]BF4 1 and [( 6-p-iPrC6H4Me)-RuCl
(
k
2-dpb)]BF4 3, reacted with N3ꢀ, CNꢀ and SCNꢀ in methanol to
afford the compounds [(
6-p-iPrC6H4Me)Ru( 2-dpa)(N3)]BF4 6,
[(
6-p-iPrC6H4Me)Ru( 2-dpa)(CN)]BF4 7, [( 6-p-iPrC6H4Me)Ru(k2
dpa)(NCS)]BF4 8, [(
6-p-iPrC6H4Me)Ru( 2-dpb)(N3)]BF4 9, [(h6
p-iPrC6H4Me)Ru( 2-dpb)(CN)]BF4 10, and [(
h
k
h
k
h
-
-
h
k
k
h
6-p-iPrC6H4Me)Ru
(k
2-dpb)(NCS)]BF4 11, wherein labile Clꢀ group from the respective
precursorcompoundshasbeenreplacedbyNꢀ3 , CNꢀ orSCNꢀ. Asimple
scheme showing the synthesis of 1e11 is depicted in Scheme 1.
The compounds under investigation are air-stable solids, soluble
in polar organic solvents such as chloroform, methanol, ethanol,
dichloromethane, acetonitrile, dimethylformamide, dimethylsulf-
oxide and insoluble in diethyl ether, benzene and hexane. The
compounds have been characterized by elemental analyses, IR, 1H
NMR, electronic spectral and electrochemical studies. All the
compounds gave satisfactory elemental analyses (recorded in
Section 4) and supported the proposed formulations.
region corresponding to ligand based
pep* transitions with over-
lapping metal-to-ligand (MLCT) transitions in the visible region [21].
The compounds under investigation are expected to give a band
corresponding to metal to ligand charge transfer (MLCT) transition
(t1g/p*), whose position depends on the metal ion and ligand
The presence of bands associated with v(C]N), v(C]C), v(CNꢀ),
v(Nꢀ3 ) and v(SCNꢀ) asymmetric stretching vibrations in the IR
spectra of respective compounds at w1595e1625, 1433e1455,
2227e2248, 2022e2043, 2100e2122 cmꢀ1, respectively suggested
the linkage of dpa, dpb CNꢀ, Nꢀ3 and SCNꢀ [18,19]. The C]C and C]N
stretching vibrations of ligands appeared at w1500e1600 cmꢀ1. In
general, these bands exhibited a shift towards higher frequencies
after coordination to metal centre in comparison to the uncoordi-
nated ligands. Further, IR spectra of the compounds displayed two
well separated strong and sharp bands assignable to CeN stretching
vibrations associated with coordinated dipyridylamine at w1251
and w1231, w1025 and w996 cmꢀ1, respectively.
acting as a
lowest energy transitions in visible region at w488e434 and
388e338 nm have been tentatively assigned to Md metal to
p-acceptor. On the basis of its intensity and position, the
p/L*
ligand charge transfer transitions (MLCT). Bands in the high-energy
side at w289e240 nm have been assigned to intra-ligand */
n/ * transitions [21,22]. Absorption bands at w251, 257 and
249 nm, respectively in the spectra of 1e10 have been assigned to
* transitions of the aromatic imine ligands [22].
Electrochemical properties of 1e3 and 5 have been followed by
p/p
p
p/p
cyclic voltammetry in acetonitrile using 0.1 M tertabutylamm
BF4
R
BF4
R
η6
μ
[{( -arene)RuCl( -Cl)}2]
arene = p-iPrC6H4Me, C6H6
Methanol
Methanol
Ru
Ru
N
+
Cl
reflux, 6 h
NH4BF4
N
reflux, 6 h
X
N
N
N
N
N
R'
N
R'
N
R'
R' = H (dpa)
R' = benzyl(dpb)
Ar-R = p-iPrC6H4Me, R '= H,
X = N3- (6), X = CN- (7), X = NCS- (8)
Ar-R = p-iPrC6H4Me, R' = benzyl,
X = N3- (9), X = CN- (10), X = NCS- (11)
Scheme 1.

P. Kumar et al. / Journal of Organometallic Chemistry 695 (2010) 2205e2212
2207
Table 1
refinement are summarized in the experimental section and
important geometrical parameters are given below the Figs. 1e4.
Compounds 1, 3 and 4 crystallize in monoclinic system with P21,
P21 and P21/c space groups. The metal centres in these iso-structral
compounds exhibited typical piano-stool geometry, which is
completed by hydrocarbon ligands p-iPrC6H4Me (coordinated in
Electrochemical data for ruthenium arene compounds 1, 2, 3, and 5 in acetonitrile
solution at (rt), scan rate 100 mV/s
Compound
E1/2 (V)
E1/2 (V)
Ru II/III
Ligand centred
1
2
3
5
0.82a
0.74a
0.79a
0.72a
ꢀ1.13, ꢀ1.37, ꢀ1.99
ꢀ1.78, ꢀ1.34,ꢀ1.89
ꢀ1.70, ꢀ1.38, ꢀ1.97
ꢀ1.24, ꢀ1.36, ꢀ1.93
h
6-mode), the chloro group and nitrogen donors from the ligand
dpa and dpb. The N-N donor ligands dpa and dpb are coordinated to
the metal centre in a bidentate chelating
2-manner through both
k
a
Irreversible peak.
the nitrogen atoms forming a six membered ring with the bite
angles of 83.2(8) (1), 81.5(2) (3), and 81.8(13)ꢁ (4), respectively. The
ꢀ
average Ru-C distances in 1, 3 and 4 are 2.199, 2.189 and 2.198 A. The
onium perchlorate (TBAP) as supporting electrolyte. Potential of the
Fc/Fcþ couple under experimental conditions was 0.10 V (80 mv) vs
Ag/Agþ. Resulting data is summarized in Table 1 and selected vol-
tammograms are depicted in Fig. S2 (supporting information). In
the anodic potential window (0 to þ 2.00 vs. Ag/Agþ) the
compounds 1e3 and 5 exhibited only one irreversible oxidation
wave at þ0.82, þ0.74, þ0.79, and þ0.72 V, respectively. These may
be attributed to metal centred Ru(II/III) oxidations. One can see that
the oxidation of ruthenium in benzene containing compounds
takes place at lower potential in comparison to those based on
p-cymene. It may be attributed to the positive inductive effect of
methyl and isopropyl groups on p-cymene ring, which favors the
oxidation of ruthenium at higher potential. The presence of one
oxidation peak at almost the same potential in these compounds
may be attributed to similar arrangement of various groups and
very close electronic environments about the metal cantres. On the
other hand, in cathodic potential window (0 to ꢀ2 vs. Ag/Agþ) both
the dpa and dpb containing compounds exhibited three ligand
based reductions (ꢀ1.13, ꢀ1.37, ꢀ1.99 V, 1; ꢀ1.34, ꢀ1.78, ꢀ1.89 V, 2;
ꢀ1.38, 1.70, ꢀ1.97 V, 3; and ꢀ1.24, ꢀ1.36, ꢀ1.93 V, 5).
Ru to centroid of the p-cymene ring distances are almost equal and
ꢀ
are 1.684 (1), 1.689 (3) and 1.686 A (4), respectively. The NeRueN
and NeRueCl angles are less than 90ꢁ [83.2(8), 81.5(2), and 81.8
(13)ꢁ] and are consistent with “piano stool” arrangement of various
groups about the metal centre. The RueN bond lengths in 1, 3 and 4
are normal and consistent with
(Ru1eN1 and Ru1eN3; Ru1eN1 and Ru1eN2; Ru1eN1 and
k
2-coordination of dpa/dpb.
ꢀ
ꢀ
Ru1eN2 are 2.102(19) and 2.106(19) A, 1; 2.101(6) and 2.105(6) A 3;
ꢀ
2.102(3) and 2.100(3) A 4). The MeCl bond distances in 1, 3 and 4
are 2.395(7), 2.401(19) and 2.404(11) A, respectively. The RueN,
ꢀ
RueC and RueCl bond distances and various angles support “piano
stool” geometry about the metal centre and are close to the one
reported in other closely related compounds [23].
Compound 5 which is iso-structural with 1, 3 and 4 crystallizes in
orthorhombic crystal system with Pca21 space groups. In the asym-
metric unit of 5, there are two independent molecules which are
essentially identical. Overall arrangementof various groups about the
ruthenium centre in this compound also, adapted piano-stool
geometry which is completed by hydrocarbon ligand C6H6 (bonded
in h
6-manner), the chloro group and two nitrogen donors from dpb.
In this compound ligand dpb is coordinated to the metal centre in
bidentate manner forming a six membered ring with the bite angles
of 82.4(5) and 82.9(6)ꢁ. Average RueC distances in the two inde-
2.2. Molecular structures
ꢀ
pendent molecules are 2.176 and 2.190 A and centroids of the
The molecular structures of 1, 3, 4 and 5 have been determined
by single crystal X-ray diffraction analyses. ORTEP views at 30%
thermal ellipsoid probability with atom numbering scheme are
shown in Figs. 1e4. Details about the data collection, solution and
ꢀ
benzene rings are separated from Ru by 1.674 and 1.686 A, respec-
tively. The Ru-N distances are normal and are comparable with the
distances in other ruthenium compounds containing heterocyclic
ꢁ
ꢀ
Fig. 1. Molecular structure and selected bond lengths (A) and angles ( ) of 1: Ru1eN1 2.102(19), Ru1eN3 2.106(13), Ru1eCl3 2.395 (7), Ru1eCav(arene) 2.199(2), CgeRu1 1.684,
N1eRu1eN3 83.27(8), N1eRu1eCl3 85.77(6), N3eRu1eCl3 87.01(6), Cl3eRu1eCg 128.48, N1eRu1eCg 128.44, N3eRu1eCg 128.50.

2208
P. Kumar et al. / Journal of Organometallic Chemistry 695 (2010) 2205e2212
ꢁ
ꢀ
Fig. 2. Molecular structure and selected bond lengths (A) and angles ( ) of 3: Ru1eN1 2.105(6), Ru1eN2 2.101(6), Ru1eCl1 2.408(9), Ru1eCav(arene) 2.189(7), Cg Ru1 1.689, N1e
Ru1eN2 81.50(2), N1eRu1-Cl1 85.59(16), N2eRu1eCl1 85.96(17), Cl1eRu1eCg 128.09, N1eRu1eCg 129.44, N2eRu1eCg 128.44.
ꢀ
ligands. The MeCl bond distances are 2.403(3) and 2.409(3) A,
respectively and are consistent with the reported values [23].
Crystal structures of 1, 3, 4, and 5 revealed the presence of
extensive intra- and inter-molecular CeH/F interactions leading
to supramolecular architectures [23,24]. In compound 1, counter
ion BFꢀ4 is encapsulated in the self-assembled cavity generated by
weak interactions (Fig. S3). Some interesting motifs resulting from
examined the catalytic activity of 1e3 and 5 towards reduction of
carbonyl group of ketones (Table 2).
Reduction of acetophenone or benzophenone to 1-phenyl-
ethanol or 1,1-diphenylmethanol by 2-propanol was chosen as the
model reaction to test the catalytic activity of arene Ru(II) NeN
O
OH
O
OH
CeH/p interactions in 1, 3, 4, and 5 are depicted in Figs. S4 and S5.
Ru(II) cat., 820C
KOH
+
+
(1)
R1
R1
2.3. Catalytic behavior of compounds 1e3, and 5
R2
R2
Encouraged by applications of half-sandwich arene ruthenium
compounds in transfer hydrogenation catalysis [25], we have
ꢁ
ꢀ
Fig. 3. Molecular structure and selected bond lengths (A) and angles ( ) of 4: Ru1eN12.102(3), Ru1eN2 2.100(3), Ru1eCl1 2.404 (11), Ru1eCav(arene) 2.198(4), Cg Ru1 1.686,
N1eRu1eN2 81.85(13), N1eRu1eCl1 86.41(9), N2eRu1eCl1 86.99(9), Cl1eRu1eCg 126.98, N1eRu1eCg 129.14, N2eRu1eCg 129.89.

P. Kumar et al. / Journal of Organometallic Chemistry 695 (2010) 2205e2212
2209
ꢁ
ꢀ
Fig. 4. Molecular structure and selected bond lengths (A) and angles ( ) of 5: Ru1eN12.038(15), Ru2eN4 2.093(15) Ru1eN3 2.069(14), Ru2eN6 2.067(14), Ru1eCl1 2.409(4),
Ru2eCl2 2.403(3), Ru1eCav(arene) 2.176(14), Ru2eCav(arene) 2.190(16), CgeRu1 1.674, CgeRu2 1.686, N1eRu1eN2 82.40(5), N4eRu2eN6 82.90(6), N1eRu1eCl1 85.30(4),
N4eRu2eCl2 85.0(3), N3eRu1eCl1 84.50(3), N6eRu2eCl2 85.20(3), Cl1eRu1eCg 128.09, Cl2eRu2eCg 127.79, N1eRu1eCg 129.02, N4eRu2eCg 129.36, N3eRu1eCg 129.03,
N6eRu2eCg 129.43.
compounds (Eq. (1)). The reaction products were analysed by 1H
NMR spectroscopy and conditions employed are summarized in the
experimental section. The reactions with or without addition of KOH
were explored for all the isolated halide precursors. The activities of
these compounds towards hydrogenation of ketones were found to
be moderate. Better results obtained for acetophenone in compar-
ison to benzophenone however, the differences were not marked. It
suggested that the size of substituents on ketone is of little impor-
tance. In presence of a base like KOH, the p-cymene compounds
containing dipyridylamine and its derivatives displayed higher
activity than those based on benzene. The highest activity levels
were found with the compounds 1 and 3 (Table 2). The activities of
compounds have been explained on the basis of electron releasing
groups present on aromatic ring and electronic effects about the
metal centre. It has been observed that the presence of electron
releasing groups on the aromatic ring increases electron density on
metal centre and the rate of transfer hydrogenation.
It is remarkable that these compounds are active in hydroge-
nation process in the absence of a base. The addition of a base is
usually necessary in transfer hydrogenations [26] except, if
a hydride which is usually unstable, is used as the starting
material [27] or some sort of activation of the precursor is previ-
ously necessary [28]. In the present study, best results were ach-
ieved with 1 and 3 suggesting that the p-cymene compounds are
more active in the absence of a base. Although, a tentative
mechanism for these reactions have been proposed here, a prior
step involving formation of the hydrides was thought to be
OH
OH
Table 2
+ base
Hydrogen transfer reactions of the compounds 1, 2, 3 and 5.
H
R '
base +
H
R
R
R
Entry
Catalyst benzophenone
With base
Yielda (%)
Without base
Yielda (%)
M
TONb
TONb
1
2
3
4
1
2
3
5
96
84
99
90
480
420
495
450
30
25
58
42
150
125
290
210
baseH+
O-M
baseH+
R
H
Acetophenone
R
O-M
5
6
7
8
1
2
3
5
98
90
100
94
490
450
500
470
87
61
42
37
435
305
210
185
R '
R
Reaction condition: in isopropanol with 2% catalyst w/w at 82 ꢁC.
O
O
Yields and TON of the hydrogen transfer reactions of the compounds 1, 2, 3 and 5
with benzophenone and acetophenone (reaction conditions are given in experi-
mental Section 4.2.12).
M-H
R '
R
R
R
a
Isolated yield.
b
TON, turnover number ¼ no. of moles of product/no. of moles of catalyst per unit
Scheme 2. Monohydride inner sphere mechanism for hydrogen transfer from
a secondary alcohol to a ketone (M represents a transition metal compounds).
time.

2210
P. Kumar et al. / Journal of Organometallic Chemistry 695 (2010) 2205e2212
necessary. It is reasonable that these hydrides can be formulated
as [Ru(arene)H(L)]þ. The partial de-coordination of N-donor
ligand is also necessary to allow coordination of the ketone. On the
basis of behavior of 1e5 in solution and their synthesis as depicted
in Scheme 1, an inner sphere mechanism [29] has been proposed
for transfer hydrogenation (TH) of ketones catalysed by chelated
compound 1 as an orange solid which was recrystallized from
CH2Cl2-petroleum ether (40e60 ꢁC). Yield: 0.528 g, 86%. Microan-
alytical data: C20H23ClN3RuBF4 [Mr ¼ 528.7 g/mole] requires:
C, 45.52; H, 4.20; N, 7.96%. Found: C, 45.50; H, 4.18; N, 7.98%. 1H
NMR (
CH(CH3)2}, 5.69 {m, 4H,
d ppm): 1.28 (d, 12H, CH(CH3)2), 1.84 (s, 6H, CH3), 2.82 {m, 2H,
h
6-p-iPrC6H4Me (C6H4)}, 6.01 {m, 4H, h6
-
h
n-compounds. Compounds interact with 2-propanol in presence
p-iPrC6H4Me (C6H4)}, 11.6 (s, 1H. NH), 8.11 (t, 2H), 7.60 (t, 2H), 7.26
(t, 2H), 7.10 (d, 2H). IR (KBr pellet, cmꢀ1): 3400 (s), 1626 (s), 1577 (s),
1470 (s), 1424 (s), 1396 (m), 1317 (w), 1251 (s), 1228 (s), 1144 (m),
1075 (w), 1028 (s), 1003 (w), 995 (s), 915 (w), 878 (w), 790 (s), 773
of KOH to form Ru(II)eOCHR2 (A), which in turn results in the
formation of RueH (B) intermediate with the release of ketone.
Coordination of a ketone with B results in the formation of an
alcohol (scheme 2). Formation of the compounds containing
RueH from RueCl precursors are well-documented, [30] such as
in situ generated RueH species can act as the active catalysts for
TH of ketones [30e32].
(s), 698 (s), 528 (m),
n(BF4) 1056. UVevis. (CH3CN, lmax nm, e): 457
(890), 338 (15080), 273 (38410), 249 (38910).
4.2.2. Synthesis of [(
Compound
(0.500 g, 1.0 mmol) in place of [{( m-Cl)Cl}2],
h k
6-C6H6)RuCl( 2-dpa)]BF4 (2)
2
was prepared using [{( -Cl)Cl}2]
h
6-C6H6)Ru(
m
3. Conclusions
h
6-p-iPrC6H4Me)Ru(
following the above procedure for 1. It isolated as a yellow micro-
crystalline solid. Yield: 0.472 g, 94%. Microanalytical data:
C16H15ClN3RuBF4 [Mr ¼ 472.64 g/mole] requires: C, 40.66; H, 3.20;
Through this work we have demonstrated that the ligands 2,20-
dipyridylamine (dpa) and di-2-pyridylbenzylamine (dpb) reacted
with arene ruthenium compounds to afford a series of mononuclear
compounds in good yields. The reactivity of resulting compounds
have been examined with various bases to afford substitution prod-
N, 8.89%. Found: C, 40.62; H, 3.24; N, 8.86%. 1H NMR (
d ppm): 5.68 (s,
6H, C6H6), 10.4 (s, 1H), 8.10 (t, 2H), 7.64 (t, 2H), 7.36 (t, 2H), 7.15 (d,
2H). IR (KBr pellets, cmꢀ1): 3432 (s),1595 (s),1520 (w),1469 (s),1433
(s),1394 (m),1255 (s),1230 (s) 1184 (m),1136 (m),1079 (m),1028 (s),
ucts [(
h
6-arene)Ru(dpa)X]þ, and [(
h
6-arene)Ru(dpb)X]þ (X ¼ N3ꢁ, CNꢁ
and SCNꢁ). Chelation of the ligands dpa and dpb through nitrogen
donor sites has been authenticated crystallographically. Furthee, it
has been shown that the compounds 1e3 and 5 moderately catalyze
reduction of ketones to corresponding alcohol and serve as an effec-
tive hydrogenating catalyst even in absence of a base.
994 (m) 844 (s), 758 (s), 698 (s),
n(BF4) 1056. UVevis. (CH3CN, lmax
nm, ): 485 (1980), 375 (15400), 285 (38070), 245 (38570).
e
4.2.3. Synthesis of [(h k
6-p-iPrC6H4Me)RuCl( 2-dpb)]BF4 (3)
To a suspension of [{( -Cl)Cl}2] (0.612 g,
6-p-iPrC6H4Me)Ru(
h
m
1.0 mmol) in methanol (25 ml), dpb (0.261 g, 1.0 mmol) was added
and the contents of flask were heated under reflux overnight.
Resulting reaction mixture was filtered to remove any solid
impurities. A saturated solution of ammonium tetrafluroborate
dissolved in 5 ml methanol was added to the filtrate and left for
slow crystallization in a refrigerator. Slowly, yellow microcrys-
talline product separated which was filtered, washed with diethyl
ether and dried in vaccuo. Yield: 0.512 g, 83%. Microanalytical
data: C27H29BClF4N3Ru [Mr ¼ 618.87 g/mol] requires: C, 52.40; H,
4. Experimental
4.1. Reagents and general methods
All the synthetic manipulations were performed under aerobic
conditions. The solvents were rigorously purified by standard
procedures prior to their use [33]. Hydrated ruthenium(III)
chloride,
eAldrich) were used as received without further purifications. The
precursor complexes, [{(
6-arene)Ru(
-Cl)Cl}2] [34] (arene ¼ C6H6,
a
-phellandrene, 2,20-dipyridylamine (dpa) (all Sigma-
4.72; N, 6.79%. Found: C, 52.42; H, 4.70; N, 6.80%. 1H NMR (
d
ppm):
1.30 {d, 12H, CH(CH3)2}, 1.86 (s, 6H, CH3), 2.80 {m, 2H, CH(CH3)2},
5.64 {m, 4H,
6-p-iPrC6H4Me (C6H4)}, 6.11 {m, 4H, 6-p-iPrC6H4Me
h
m
and p-iPrC6H4Me) and the ligand di-2-pyridylbenzylamine (dpb)
[35] were prepared and purified following the literature proce-
dures. Elemental analyses for C, H and N were performed on an
Exeter Analytical Inc. Model CE-440 Elemental Analyzer. IR and
electronic absorption spectra were recorded on a Varian 3300 FT-IR
and Shimadzu UV-1700 series spectrophotometers, respectively. 1H
NMR spectra were obtained on a JEOL AL 300 FT-NMR spectrometer
at room temperature using DMSO-d6 as a solvent. Residual
protonated species in the deuterated solvents were used as internal
references; all the 1H shifts (s ¼ singlet, d ¼ doublet, t ¼ triplet,
sept ¼ septet, m ¼ multiplet, br ¼ broad) are reported relative to the
external TMS. Cyclic voltammetric measurements were performed
on a CHI 620c Electrochemical Analyzer. Platinum working elec-
trode, platinum wire auxiliary electrode, and Ag/Agþ reference
electrode were used in a standard three-electrode configuration.
Tetrabutylammonium perchlorate (TBAP) was used as the sup-
h
h
(C6H4)}, 8.24 (d, 2H), 7.95 (t, 2H), 7.86 (s, 2H), 7.45 (d, 2H), 7.23 (d,
2H), 7.06 (d, 3H), 5.41 (s, 2H). (KBr pellets, cmꢀ1): 3083 (w), 3037
(w), 1599 (s), 1487 (s), 1459 (s), 1445 (s), 1345 (m), 1265 (m), 1228
(m), 1144 (m), 1053 (w), 1029 (s), 1003 (w), 988 (s), 915 (w), 878
(w), 790 (s), 773 (s), 698 (s), 528 (m), 502 (w), 448 (w), 435 (w).
UVevis. (CH3CN, lmax nm, e): 452 (1480), 352 (4870), 290 (38240),
242 (39240).
4.2.4. Synthesis of [(h k
6-p-iPrC6H4Me)RuCl( 2-dpb)]PF6.MeOH (4)
It was prepared following exactly the same procedure for 3,
except that ammonium hexafluorophosphate was used in place of
ammonium tetrafluroborate. Yield: 0.492 g, 80%. Microanalytical
data: C28H33PClOF6N3Ru [Mr ¼ 709.08 g/mol] requires: C, 47.43; H,
4.69; N, 5.93%. Found: C, 47.40; H, 4.70; N, 5.91%.
porting electrolyte and solution concentration was ca. 10ꢀ3
.
4.2.5. Synthesis of [(
Compound was prepared using [{(
(0.500 g, 1.0 mmol) in place of [{(
6-p-iPrC6H4Me)Ru(
h
6-C6H6)RuCl(
k
2-dpb)]PF6 (5)
6-C6H6)Ru(
4
h
m-Cl)Cl}2]
-Cl)Cl}2]
4.2. Syntheses
h
m
following the above procedure for 3. Yield: 0.432 g, 86%. Micro-
analytical data: C23H21ClF6N3PRu [Mr ¼ 620.93 g/mole] requires: C,
44.49; H, 3.41; N, 6.77%. Found: C, 44.52; H, 3.39; N, 6.78%. 1H NMR
4.2.1. Synthesis of [(
h
6-p-iPrC6H4Me)RuCl(
k
2-dpa)]BF4 (1)
To a suspension of [{(
h
6-p-iPrC6H4Me)Ru(
m-Cl)Cl}2] (0.612 g,
1.0 mmol) in methanol (25 ml), dpa (0.171 g, 1.0 mmol) was added
and the contents of flask were heated under reflux for 8 h. After
cooling to room temperature orange solution thus obtained was
concentrated to dryness under reduced pressure. It afforded
(d ppm): 5.64 (s, 6H, C6H6), 8.10 (d, 2H), 7.64 (t, 2H), 7.36 (t, 2H), 7.15
(d, 2H), 7.23 (d, 2H), 7.06 (d, 3H), 5.43 (s, 2H). IR (KBr pellets, cmꢀ1):
3085 (w), 3040 (w), 1610 (s), 1577 (s), 1487 (s), 1444 (s), 1427 (s),
1345 (m), 1255 (s), 1230 (m), 1146 (m), 1030 (w), 1003 (w), 989 (w),

P. Kumar et al. / Journal of Organometallic Chemistry 695 (2010) 2205e2212
2211
878 (w), 790 (s), 773 (s), 698 (s), 528 (m), 502 (w), 440 (w), 436 (w),
(PFꢀ6 ) 840. UVevis. (CH3CN, lmax nm,
): 473 (1030), 342 (9220),
283 (22130), 257 (38750).
(BF4) 1056. UVevis. (CH3CN, lmax nm,
309 (10430), 268 (22130).
The compounds 10e11 were synthesized following exactly the
same procedure as adopted for 9. Characterization data of the
compounds is summarized below.
e
): 439 (1722), 347 (1850),
n
e
4.2.6. Synthesis of [(h k
6-p-iPrC6H4Me)Ru( 2-dpa)(N3)]BF4 (6)
To a methanolic suspension of 1 (0.1 g, 0.18 mmol), NaN3 (0.012 g,
0.18 mmol) was added and refluxed for 4 h, whereupon yellow
solution turned pale yellow in color. The solvent was rotatory
evaporated and yellow solid thus obtained was dissolved in CH2Cl2
and filtered. The filtrate was concentrated to 2 ml and hexane was
added to induce precipitation. Light yellow product separated which
was washed with diethyl ether and dried under vacuum. Yield:
0.078 g, 78%. Microanalytical data: C20H23N6RuBF4 [Mr ¼ 534.31 g/
mole]requiresC, 44.96; H, 4.15;N,15.73%. Found:C, 44.98; H, 4.12; N,
4.2.10. Characterization data of [(h k
6-p-iPrC6H4Me)Ru( 2-dpb)(CN)]
BF4 (10)
Yield: 0.097 g, 97%. Microanalytical data: C28H29BF4N4Ru
[Mr ¼ 609.44 g/mole] requires: C, 55.18; H, 4.80; N, 9.19%. Found: C,
55.20; H, 4.82; N, 9.20%. 1H NMR (
d ppm): 1.26 {d, 12H, CH(CH3)2},
1.79 (s, 6H, CH3), 2.86 {m, 2H, CH(CH3)2}, 5.40 {m, 4H,
h
6-p-iPrC6H4Me (C6H4)}, 6.12 {m, 4H, 6-p-iPrC6H4Me (C6H4)}, 8.70
h
(d, 2H), 7.88 (t, 2H), 7.41 (s, 2H), 7.33 (d, 2H), 7.25 (d, 2H), 7.11 (d, 3H),
5.48 (s, 2H). IR (KBr pellets, cmꢀ1): 3083 (w), 3037 (w), 2237 (s),1618
(s),1568 (s),1544 (s),1488 (s),1436 (s),1336 (m),1245 (m),1226 (m),
1136 (m), 1086 (w), 1026 (w), 993 (s), 919 (w), 874 (w), 794 (s), 774
15.70%. 1H NMR (
2.84 {m, 2H, CH(CH3)2}, 5.70 {m, 4H,
{m, 4H,
d
ppm): 1.34 {d, 12H, CH(CH3)2}, 1.81 (s, 6H, CH3),
h
6-p-iPrC6H4Me (C6H4)}, 6.10
h
6-p-iPrC6H4Me (C6H4)},12.1 (s,1H), 8.10 (t, 2H), 7.64 (t, 2H),
7.24 (t, 2H), 7.11 (d, 2H). (KBr pellets, cmꢀ1): 3424 (s), 2022 (s), 1620
(s),1575 (s),1477 (s),1426 (s),1390 (m),1316 (w),1264 (m),1228 (m),
1145 (m), 1065 (w), 1000 (w), 992 (s), 912 (w), 876 (w), 791 (s), 776
(s), 694 (s), 525 (m), 504 (w), 445 (w), 436(w),
UVevis. (CH3CN, lmax nm, ): 454 (1378), 345 (8639), 253 (29560).
n .
(BF4) 1045 cmꢀ1
e
(s), 699 (s), 527 (m),
n
(BF4) 1055. UVevis. (CH3CN, lmax nm,
e
): 455
4.2.11. Characterization data of [(h k
6-p-iPrC6H4Me)Ru( 2-dpb)
(1310), 360 (11630), 288 (22276), 240 (29580).
(NCS)]BF4 (11)
The compounds 7e8 were synthesized following exactly the
same procedure as adopted for 6. Characterization data of these
compounds are given below.
Yield: 0.076 g, 76%. Microanalytical data: C28H29BF4SN4Ru
[Mr ¼ 641.50 g/mole] requires: C, 52.43; H, 4.56; N, 8.73%. Found: C,
52.41; H, 4.58; N, 8.74%. 1H NMR (
d ppm): 1.27 {d, 12H, CH(CH3)2},
1.78 (s, 6H, CH3), 2.89 {m, 2H, CH(CH3)2}, 5.42 {m, 4H, h6
p-iPrC6H4Me (C6H4)}, 6.10 {m, 4H, 6-p-iPrC6H4Me (C6H4)}, 8.70 (d,
-
4.2.7. Characterization data of [(
h
6-p-iPrC6H4Me)Ru(
k
2-dpa)(CN)]
h
BF4 (7)
2H), 7.88 (t, 2H), 7.41 (s, 2H), 7.33 (d, 2H), 7.25 (d, 2H), 7.11 (d, 3H),
5.45 (s, 2H). IR (KBr pellets, cmꢀ1): 3076 (w), 3026 (w), 2118 (s),1608
(s),1576 (s),1542 (s),1465 (s),1433 (s),1330 (m),1240 (m),1224 (m),
1138 (m), 1088 (w), 1027 (w), 996 (s), 914 (w), 877 (w), 788 (s), 764
Yield: 0.098 g, 98%. Microanalytical data: C21H23N4RuBF4
[Mr ¼ 519.31 g/mole] requires C, 48.57; H, 4.46; N, 10.79%. Found: C,
48.55; H, 4.44; N, 10.80%. 1H NMR (
d ppm): 1.33 {d, 12H, CH(CH3)2},
1.77 (s, 6H, CH3), 2.80 {m, 2H, CH(CH3)2}, 5.71 {m, 4H, p-iPrC6H4Me
(C6H4)}, 6.14 {m, 4H, p-iPrC6H4Me (C6H4)}, 10.1 (s, 1H), 8.24 (t, 2H),
7.54 (t, 2H), 7.34 (t, 2H), 7.10 (d, 2H). IR (KBr pellet, cmꢀ1): 3424 (s),
2227 (s),1625 (s),1577 (s),1474 (s),1430 (s),1394 (m),1320 (w),1255
(m),1232 (m),1145 (m),1065 (w),1020 (w), 996 (s), 922 (w), 877 (w),
(s), 692 (s), 521 (m), 501 (w), 442 (w), 433 (w),
n(BF4) 1056. UVevis.
(CH3CN, lmax nm, ): 442 (1456), 355 (4872), 248 (26734).
e
4.2.12. General procedure for the catalytic studies
Hydrogen transfer experiments for hydrogenation of aceto-
phenone or benzophenone were carried out using 2-propanol as
the solvent and hydrogen source at the refluxing temperature of
solvent (82 ꢁC). Each run was repeated thrice to ensure reproduc-
ibility. Following general procedure was employed: A solution of
ketone (1 mmol), KOH (0.2 ml of a 0.2 M solution in 2-propanol)
and corresponding catalyst (0.002 mmol) was heated under reflux
in 10 ml of 2-propanol for 24 h. 2-Propanol was removed under
vaccum and an aliquot of remaining product was analysed by 1H
NMR in CDCl3. The yield of the process was calculated considering
the relative integrals of ketone and alcohol.
792 (s), 774 (s), 690 (s), 526 (m),
n(BF4) 1055. UVevis. (CH3CN, lmax
nm, ): 458 (1542), 355 (10632), 286 (20276), 251 (36810).
e
4.2.8. Characterization data of [(h k
6-p-iPrC6H4Me)Ru( 2-dpa)(SCN)]
BF4 (8)
Yield: 0.082 g, 82%. Microanalytical data: C21H23N4SRuBF4
[Mr ¼ 551.37 g/mole] requires C, 45.75; H, 4.20; N, 10.16%. Found: C,
45.73;H, 4.22;N,10.14%.1HNMR(
dppm):1.31{d,12H, CH(CH3)2},1.77
(s, 6H, CH3), 2.80 {m, 2H, CH(CH3)2}, 5.71 {m, 4H, h
6-p-iPrC6H4Me
(C6H4)}, 6.14 {m, 4H, h
6-p-iPrC6H4Me (C6H4)}, 11.1 (s, 1H), 8.26 (t, 2H),
7.52 (t, 2H), 7.32 (t, 2H), 7.11 (d, 2H). IR (cmꢀ1, KBr pellet): 3411 (s),
2100 (s), 1610 (s),1587 (s),1477 (s),1428 (s), 1388 (m),1322 (w),1261
(m),1228 (m),1142 (m),1065 (w),1022 (w), 998 (s), 920 (w), 876 (w),
4.2.13. X-ray structure determinations
Suitable crystals for single crystal X-ray diffraction analyses for
790 (s), 773 (s), 692 (s), 526 (m),
n
(BF4) 1055. UVevis. (CH3CN, lmax
1, 3, 4 and 5 were obtained from CH2Cl2/petroleum ether
nm, ): 460 (1742), 345 (9945), 283 (19276), 253 (32843).
e
(40e60 ꢁC) at room temperature by slow diffusion method.
Preliminary data on the space group and unit cell dimensions as
well as intensity data were collected on Rigaku-RAXIS RAPID II
4.2.9. Synthesis of [(
h
6-p-iPrC6H4Me)Ru( 2-dpb)(N3)]BF4 (9)
k
Compound 9 was prepared using 3 (0.1 g, 0.16 mmol) and
NaN3 (0.011 g, 0.16 mmol) following the method for 6. Yield:
diffractometer
using
graphite-monochromatized
Mo-Ka
ꢀ
(
l
¼ 0.71073 A) radiation. Structures were solved by direct methods
0.082 g,
[Mr ¼ 625.44 g/mole] requires: C, 51.85; H, 4.67; N, 13.44%.
Found: C, 51.86; H, 4.70; N, 13.46%. 1H NMR (
ppm): 1.28 {d, 12H,
CH(CH3)2}, 1.84 (s, 6H, CH3), 2.82 {m, 2H, CH(CH3)2}, 5.60 {m, 4H,
6-p-iPrC6H4Me (C6H4)}, 6.10 {m, 4H, 6-p-iPrC6H4Me (C6H4)},
82%.
Microanalytical
data:
C27H29BF4N6Ru
(SHELXS 97) and refined by full-matrix least squares on F2 (SHELX
97) [36]. Non-hydrogen atoms were refined with anisotropic
thermal parameters. All the hydrogen atoms were geometrically
fixed and allowed to refine using a riding model. The computer
program PLATON was used for analyzing the interaction and
stacking distances [36c]. CCDC-742999 (1), 768447 (3), 768449 (4),
and 768448 (5) contain supplementary crystallographic data for
this paper.
d
h
h
8.69 (d, 2H), 7.77 (t, 2H), 7.86 (s, 2H), 7.37 (d, 2H), 7.26 (d, 2H),
7.08 (d, 3H), 5.55 (s, 2H). IR (KBr pellets, cmꢀ1): 3088 (w), 3043
(w), 2037 (s), 1598 (s), 1540 (s), 1477 (s), 1445 (s), 1346 (m), 1255
(m), 1230 (m), 1146 (m), 1080 (w), 1020 (w), 985 (s), 918 (w), 876
Compound 1. Formula C20H23ClN3RuBF4, Mr ¼ 528.7, Monoclinic,
ꢀ
ꢀ
ꢀ
(w), 792 (s), 772 (s), 696 (s), 528 (m), 502 (w), 448 (w), 438 (w)
n
space group P21, a ¼ 8.8572(2) A, b ¼ 12.9699(2) A, c ¼ 9.5615(2) A,

2212
P. Kumar et al. / Journal of Organometallic Chemistry 695 (2010) 2205e2212
3
ꢀ
[8] (a) C. Tsiamis, A.G. Hatzidimitriou, L.C. Tsvellas, Inorg. Chem. 37 (1998)
2903e2909;
b
m
¼ 105.70(2)ꢁ,
V ¼ 1057.40(4) A ,
Z ¼ 3,
Dc ¼ 2.486 g cmꢀ3
,
¼ 1.371, T(K) ¼ 293(2),
l
¼ 0.71073, R(all) ¼ 0.0246, R(I > 2 (I)) ¼
s
(b) F. Ugozzoli, A.M.M. Landfrei, N. Marsich, A. Camus, Inorg. Chim. Acta 256
(1997) 1.
0.0212, wR2 ¼ 0.0419, wR2 [I > 2
s
(I)] ¼ 0.0414, GooF ¼ 0.903.
[9] (a) R.A. Jacobson, W.P. Jensen, Inorg. Chim. Acta 114 (1986) L9e10;
(b) R.A. Jacobson, W.P. Jensen, Inorg. Chim. Acta 52 (1981) 205e209;
(c) G. Giorgi, R. Cini, Inorg. Chim. Acta 151 (1988) 153.
[10] W.L. Johnson, J.F. Geldard, Inorg. Chem. 18 (1979) 664e669.
[11] C. Tu, J. Lin, Y. Shao, Z. Guo, Inorg. Chem. 42 (2003) 5795e5797.
[12] (a) T. Chao, Y. Shao, N. Gan, Q. Xu, Z. Guo, Inorg. Chem. 43 (2004) 4761e4766;
(b) T.J. Hurley, M.A. Robinson, Inorg. Chem. 7 (1968) 33e38.
[13] D.P. Segers, Ph.D. Thesis, North Carolina State University.
[14] Y. Wang, Y. Mizubayashi, M. Odoko, N. Okabe, Acta Crystallogr., Sect. C 61
(2005) m67.
[15] (a) I. Puscasu, C. Mock, M. Rauterkus, A. Rondigs, G. Tallen, S. Gangopadhyay,
J.E.A. Wolff, B. Krebs, Z. Anorg. Allg. Chem. 627 (2001) 1292;
(b) M.J. Rauterkus, S. Fakih, C. Mock, I. Puscasu, B. Krebs, Inorg. Chim. Acta
350 (2003) 355e365.
[16] S. Fakih, W.C. Tung, D. Eierhoff, C. Mock, B. Krebs, Z. Anorg. Allg. Chem. 631
(2005) 1397.
Compound 3. Formula C27H29BClF4N3Ru, Mr ¼ 618.87, Mono-
ꢀ
ꢀ
clinic, space group P21, a ¼ 8.8406(18) A, b ¼ 14.766(3) A, c ¼ 10.488
3
ꢀ
ꢀ
(2) A,
m
b
¼ 100.59(3)ꢁ, V ¼ 345.7(5) A , Z ¼ 2, Dc ¼ 2.095 g cmꢀ3
,
¼ 1.321, T(K) ¼ 293(2),
l
¼ 0.71073, R(all) ¼ 0.0716, R(I > 2 (I)) ¼
s
0.0647, wR2 ¼ 0.1642, wR2 [I > 2 (I)] ¼ 0.1531, GooF ¼ 1.070.
s
Compound 4. Formula C28H33ClF6N3OPRu, Mr ¼ 709.08, Mono-
ꢀ
3
ꢀ
ꢀ
clinic, space group Pꢁ21/c, a ¼ 17.681(4) A, b ¼ 11.002(2) A, c ¼ 17.451
ꢀ3
ꢀ
(4) A,
m
b
¼115.83(3) , V ¼ 3055.6(11) A , Z ¼ 4, Dc ¼ 1.570 g cm
,
¼ 0.718, T(K) ¼ 293(2),
l
¼ 0.71073, R (all) ¼ 0.0662, R(I > 2 (I)) ¼
s
0.0460, wR2 ¼ 0.1421, wR2 [I > 2 (I)] ¼ 0.1285, GooF ¼ 0.996.
s
Compound 5. Formula C23H21ClF6N3PRu, Mr ¼ 620.93, Ortho-
ꢀ
3
ꢀ
rhombic, space group Pca21, a ¼ 12.928(3) A, b ¼ 12.977(3), c ¼ 27.816
ꢀ3
,
ꢁ
(6),
m
a
¼
b
¼
g
¼ 90.00 , V ¼ 4666.6(18) A , Z ¼ 4, Dc ¼ 1.768 g cm
[17] (a) P. Stepnicka, J. Ludvik, J. Canivet, G. Süs-Fink, Inorg. Chim. Acta 359 (2006)
2369e2374 and references therein;
¼ 0.921, T(K) ¼ 293(2),
l
¼ 0.71073, R(all) 0.1671, R(I > 2 (I)) ¼
s
(b) E. Wong, C.M. Giandomenico, Chem. Rev. 99 (1999) 2451e2466;
(c) R.H. Crabtree, The Organometallic Chemistry of the Transition Metals. John
Wiley and Sons, Hoboken, NJ, 2005.
0.0679, wR2 ¼ 0.1490, wR2 [I > 2 (I)] ¼ 0.1133, GooF ¼ 0.906.
s
Acknowledgements
[18] W.D. Stalleup, D. Williams, J. Chem. Phys. 10 (1942) 199e205.
[19] D. Seybold, K.Z. Dehnicke, Z. Anorg. Allg. Chem. 361 (1968) 277e280.
[20] J.L. Kahl, K.W. Hanck, M.K. DeArmond, J. Inorg. Nucl. Chem. 41 (1976) 495e497.
[21] (a) P. Kopel, Z. Travnicek, L. Kvitek, R. Panchartkova, M. Biler, M. Marek,
M. Nadvornik, Polyhedron 18 (1999) 1779e1784;
(b) S. Kar, T.A. Millar, S. Chakraborty, B. Sarkar, B. Pradhan, R.K. Singh,
T. Kunda, M.D. Ward, G.K. Lahiri, Dalton Trans. (2003) 2591e2596.
[22] H.A.S. Silva, R.M. Carlos, A.J. Camargo, C.M.C. Picchi, R.H. de Almeida Santos,
B.R. McGarvey, D.W. Franco, Inorg. Chim. Acta 357 (2004) 3147e3154.
[23] (a) A. Singh, N. Singh, D.S. Pandey, J. Organomet. Chem. 642 (2002) 48e57;
(b) A. Singh, M. Chandra, A.N. Sahay, D.S. Pandey, K.K. Pandey, S.M. Mobin, M.
C. Puerta, P. Valerga, J. Organomet. Chem. 689 (2004) 1821e1834;
(c) P. Kumar, M. Yadav, A.K. Singh, D.S. Pandey, Eur. J. Inorg. Chem. (2010)
704e715.
We gratefully acknowledge financial support from the Depart-
ment of Science and Technology, Ministry of Science and Tech-
nology, New Delhi, India (Grant No. SR/SI/IC-15/2007). We are also
thankful to the Head, Department of Chemistry, Banaras Hindu
University, Varanasi (U.P.) India for extending laboratory facilities
and National Institute of Advanced Industrial Science and Tech-
nology (AIST), Osaka, Japan for providing single crystal X-ray data.
Appendix. Supplementary data
[24] (a) C.D. Nunes, M. Pillinger, A. Hazell, J. Jepsen, T.M. Santos, J. Madureira,
A.D. Lopes, I.S. Goncalves, Polyhedron 22 (2003) 2799e2807;
(b) A. Singh, A.K. Singh, M. Trivedi, D.S. Pandey, J. Organomet. Chem. 690
(2005) 4243e4251.
[25] X. Wu, J. Xiao, Chem. Commun. 46 (2007) 2449e2466 and references therein.
[26] W. Baratta, K. Siega, P. Rigo, Chem. Eur. J. 13 (2007) 7479e7486.
[27] (a) T. Ohkuma, M. Koizumi, K. Muniz, G. Hilt, C. Kabuto, R. Noyori, J. Am. Chem.
Soc. 124 (2002) 6508e6509;
CCDC 742999, and 768447e768449 contains the supplementary
crystallographic data for this paper. These data can be obtained free
of charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif. Supplementary data associ-
ated with this article can be found in the online version, at doi:10.
1016/j.jorganchem.2010.06.003.
(b) K. Abdur-Rashid, S.E. Clapham, A. Hadzovic, J. Harvey, A.J. Lough, R.H. Morris,
J. Am. Chem. Soc. 124 (2002) 15104e15118;
(c) Z.R. Dong, Y.Y. Li, J.S. Chen, B.Z. Li, Y. Xing, J.X. Gao, Org. Lett. 7 (2005)
1043e1045.
References
[28] (a) R. Castarlenas, M.A. Esteruelas, E. Oñate, Organometallics 27 (2008)
3240e3247;
(b) R. Corberan, E. Peris, Organometallics 27 (2008) 1954e1958.
[29] A. Comas-Vives, G. Ujaque, A. Lledos, Organometallics 26 (2007) 4135e4144.
[30] T. Li, R. Churlaud, A.J. Lough, K. Abdur-Rashid, R.H. Morris, Organometallics 23
(2004) 6239e6247.
[31] M.T. Reetz, X.G. Li, J. Am. Chem. Soc. 128 (2006) 1044e1045.
[32] (a) C.P. Casey, T.B. Clark, I.A. Guzei, J. Am. Chem. Soc. 129 (2007)
11821e11827;
[1] (a) S. Youngme, N. Chaichit, C. Pakawatchai, S. Booncoon, Polyhedron 21
(2002) 1279e1288;
(b) S. Youngme, N. Chaichit, N. Koonsaeng, Inorg. Chim. Acta 335 (2002) 36e42;
(c) M.J. Plater, M.R.S.J. Foreman, J.M.S. Skakle, R.A. Howie, Inorg. Chim. Acta 332
(2002) 135e145;
(d) S. Youngme, N. Chaichit, Polyhedron 21 (2002) 247e253.
[2] (a) M. Haukka, P. Da Costa, S. Luukkanen, Organometallics 22 (2003)
5137e5140;
(b) T.I.A. Gerber, A. Abrahams, P. Mayer, E. Hosten, J. Coord. Chem. 56 (2003)
1397e1407;
(c) H. Kumagai, S. Kitagawa, M. Maekawa, S. Kawata, H. Kiso, M. Munakata,
J. Chem. Soc., Dalton Trans. (2002) 2390e2396;
(d) Y. Moreno, A. Vega, S. Ushak, R. Baggio, O. Pena, E. Le Fur, J.-Y. Pivan,
E. Spodine, J. Mater. Chem. 13 (2003) 2381e2387.
(b) H. Guan, M. Iimura, M.P. Magee, J.R. Norton, G. Zhu, J. Am. Chem. Soc. 127
(2005) 7805e7814;
(c) R.L. Chowdhury, J.-E. Bajckvall, J. Chem. Soc., Chem. Commun. (1991)
1063e1064.
[33] D.D. Perrin, W.L.F. Armango, D.R. Perrin, Purification of Laboratory Chemicals.
Pergamon, Oxford, U.K., 1986.
[34] (a) M.A. Bennett, A.K. Smith, J. Chem. Soc., Dalton Trans. (1974) 233e241;
(b) M.A. Bennett, T.N. Huang, T.W. Matheson, A.K. Smith, Inorg. Synth. 21
(1982) 74.
[35] (a) B. Antonioli, D.J. Bray, J.K. Clegg, K. Gloe, O. Kataeva, L.F. Lindoy, J.C. McMurtrie,
P.J. Steel, C.J. Sumby, M. Wenzel, Dalton Trans. (2006) 4783e4794;
(b) C.-L. Chen, B.-S. Kang, C.-Y. Su, Aust. J. Chem. 59 (2006) 3e6;
(c) P.J. Steel, C.J. Sumby, Chem. Commun. (2002) 322e323.
[36] (a) S. Mackay, W. Dong, C. Edwards, A. Henderson, C. Gilmox, N. Stewart,
K. Shankland, A. Donald, University of Glasgow, Scotland (1999). (b) G.
M. Sheldrick, SHELX-97: Programme for Refinement of Crystal Structures.
University of Gottingen, Gottingen, Germany, 1997;
[3] S. Kar, N. Chanda, S.M. Mobin, F.A. Urbanos, M. Niemeyer, V.G. Puranik,
R. Jimenez-Aparicio, G.K. Lahiri, Inorg. Chem. 44 (2005) 1571e1579 and
references therein.
[4] (a) J. Pang, E.J.-P. Marcotte, C. Seward, R.S. Brown, S. Wang, Angew. Chem., Int.
Ed. 40 (2001) 4042e4045;
(b) Q.-D. Liu, W.-L. Jia, G. Wu, S. Wang, Organometallics 22 (18) (2003)
3781e3791;
(c) W.Y. Yang, L. Chen, S. Wang, Inorg. Chem. 40 (2001) 507e515.
[5] (a) C. Seward, J. Pang, S. Wang, Eur. J. Inorg. Chem. (2002) 1390e1399;
(b) J. Pang, Y. Tao, S. Freiberg, X.-P. Yang, M. D’Iorio, S. Wang, J. Mater. Chem.
12 (2002) 206e212.
[6] J.E. Johnson, T.A. Beinke, R.A. Jacobson, J. Chem. Soc. A (1971) 1371e1374.
[7] J. Sletten, K. Svardal, A. Sorensen, Acta Chem. Scand. 47 (1993) 1091e1099.
(c) A.L. Platon, Spek, Acta Crystallogr. A 46 (1990) C31.