Syntheses, structures and immobilization of ruthenium complexes bearing N,O-Schiff-base or N,N′-diamine ligands functionalized with alkoxysilyl groups

Article abstract of DOI:10.1016/j.jorganchem.2017.12.015

Condensation of γ-aminopropyltriethoxysilane and substituted salicylaldehydes in ethanol afforded three new Schiff-base compounds [(EtO)₃Si(CH₂)₃N=CHArOH] (Ar = C₆H₄, L1H; C₆H₃(4

Full text of DOI:10.1016/j.jorganchem.2017.12.015

Journal of Organometallic Chemistry 855 (2018) 33e43
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Syntheses, structures and immobilization of ruthenium complexes
0
bearing N,O-Schiff-base or N,N -diamine ligands functionalized with
alkoxysilyl groups
*
Ai-Quan Jia, Li-Miao Shi, Fule Wu, Zhi-Feng Xin, Qian-Feng Zhang
Institute of Molecular Engineering and Applied Chemistry, Anhui University of Technology, Ma'anshan, Anhui 243002, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 10 November 2017
Received in revised form
Condensation of
new Schiff-base compounds [(EtO)
L3H). Treatment of [Ru(NO)Cl ,xH
-O,N-L1)(OEt
with L1H or L2H in the presence of AgNO
L)] (L ¼ L1, 2; L2, 3). While reaction of [Ru(CO)
g-aminopropyltriethoxysilane and substituted salicylaldehydes in ethanol afforded three
t
3
Si(CH
O] with L1H in the presence of Et
)] (1) with a linear N≡O moiety. Reactions of [(h -p-cymene)RuCl(m-
2
)
3
N¼CHArOH] (Ar ¼ C
6
H
4
, L1H; C
6 3 6 2 2
H (4-Cl), L2H; C H (2,4- Bu ),
3
2
3
N in THF gave a ruthenium nitrosyl
6
December 2017
2
6
complex [RuCl
Cl)]
2
(NO)(
k
2
Accepted 11 December 2017
Available online 12 December 2017
6
2
2
3
and Et
Cl and L3H in the presence of Et
-O,N-L3)] (4). Treatment of alkoxysilyl functionalized N,N -
diamine compound N -(3-(trimethoxysilyl)propyl)ethane-1,2-diamine (L4) with [Ru(PPh Cl or
Ru(DMSO) Cl ] (DMSO ¼ dimethyl sulfoxide) or [Ru(COD)Cl (COD ¼ 1,5-cyclooctadiene) led to forma-
3 2 2 2 2 2
tion of complexes [Ru(PPh ) Cl (k N-L4)] (5), [Ru(DMSO) Cl (k N-L4)] (6), and [Ru(COD)Cl (k N-L4)] (7),
3
N afforded complexes [(
h
-p-cymene)RuCl(
k -O,N-
2
2
]
n
3
N afforded an anionic
2
0
3 2 2
ruthenium complex (Et NH)[RuCl (CO) (k
Keywords:
Ruthenium(II)
Schiff-base
Heterogeneous catalysis
X-ray structure
Immobilization
1
3
)
3
2
]
[
4
2
2 x
]
2
2
2
respectively. Complexes 1e7 were characterized by microanalyses, IR and NMR spectroscopies, and their
structures were also confirmed by single-crystal X-ray diffraction. Immobilization of complexes 2 and 5 on
SBA-15, and characterization of these hybrid heterogeneous catalysts were studied by transmission
electron microscopy (TEM), IR and low pressure N
2
adsorption/desorption measurement. The heteroge-
neous catalysts were also briefly tested for oxidation of benzyl alcohol to benzaldehyde.
©
2017 Published by Elsevier B.V.
1
. Introduction
catalytic propensity of the initial active site [4]. Being thus equip-
ped, we could optimize the immobilization procedure for ruthe-
nium complexes with bifunctional N,O- and N,N -bidentate
0
During the last few decades, the coordination and organome-
tallic chemistry of ruthenium complexes has an unprecedented
development mainly due to the disclosure of the ever increasing
potential of this class of compounds as efficient promoters in
versatile catalytic processes [1]. The majority of these ruthenium
complexes possess an appropriate balance between the electronic
and steric properties within the ligand environment. As a result of
their specific structures, these ruthenium complexes exhibit
attractive catalytic abilities and particularly an enhanced activity,
chemoselectivity and stability in target chemical transformations
chelating ligands with alkoxysilyl groups. In general the solid
catalyst support should be chemically, thermally and mechanically
stable and have a suitably high surface area and an appropriate pore
size to allow for the easy diffusion of substrates to and from the
active sites [5]. This is an important point, since weak, reversible
binding leads to the well-known and feared leaching of catalyst, the
detachment of the ruthenium complex and/or the linker from the
support [6]. Furthermore, ruthenium complexes with two mono-
dentate linkers are not necessary bound in a chelating manner,
again making them vulnerable to leaching. This problem can be
solved by using chelating linkers, which has led us to consider the
use of Schiff base as a way to introduce the desired functionality,
[
2]. Immobilizing ruthenium complexes on solid supports has
emerged as a highly effective improvement to enhance their po-
tential as catalysts in chemical reactions [3]. The best way to
immobilize ruthenium complexes consists in binding the metal
complex through one of its most stable ligands without altering the
such as a ꢀSi(OR)
3
group, owing to its ability to condense with
surface ꢀOH groups of inorganic supports and to form sol-gel
materials [7]. On the other hand, Schiff bases are common ligands
in transition metal chemistry. For example, square-planar Ni(II)
complexes of glycine Schiff bases have been widely applied in the
*
Corresponding author.
E-mail address: zhangqf@ahut.edu.cn (Q.-F. Zhang).
https://doi.org/10.1016/j.jorganchem.2017.12.015
022-328X/© 2017 Published by Elsevier B.V.
0

34
A.-Q. Jia et al. / Journal of Organometallic Chemistry 855 (2018) 33e43
asymmetric synthesis of
herein report syntheses and structures of ruthenium complexes
bearing N,O-Schiff base and N,N -diamine ligands functionalized
with alkoxysilyl groups along with immobilization of the typical
complexes on SBA-15 and characterization of these hybrid het-
erogeneous catalysts.
a
-amino acids [8]. In this contribution, we
The solution was then refluxed for 4 h, during which a color changed
from light red to dark red. The solvent was removed by vacuum, and
the residue was washed with diethyl ether (5 mL ꢂ 3) and n-hexane
0
(5 mL ꢂ 2). Recrystallization from CH
2
Cl
2 2
/Et O (1:5) gave red block
2
crystals of [RuCl
collected and dried in air. Yield: 51 mg, 85%. IR (KBr disc, cm ):
2
(NO)(k -O,N-L1)(OEt )] (1). The solid product was
2
ꢀ1
n
n
n
CꢀH ¼ 2930(s), 1440(w), 1370(s),
C¼C ¼ 1565(m), 780(m), CꢀN ¼ 1455(s),
SiꢀC ¼ 1268(s). H NMR (CDCl , ppm): 8.21 (s, 1H, CH¼N), 7.31e6.86
), 3.82e3.75 (m, 6H, O-CH ), 3.58e3.50 (m, 2H, N-CH ),
.30e3.24 (m, 4H, O-CH CH ), 1.81e1.76 (m, 2H, CH ), 1.25e1.16 (m,
), 0.68e0.60 (m, 2H, Si-CH ). Anal. Calc. for C20
n
N≡O ¼ 1790(s),
n
C¼N ¼ 1625(s),
2
. Experimental section
n
nSiꢀO ¼ 1075(s),
1
3
2.1. General considerations
(m, 4H, C
3
15H, CH
6
H
4
2
2
2
3
2
All manipulations were carried out under nitrogen by standard
3
2
36 2 6-
H N O
Schlenk techniques. Solvents were purified, distilled and degassed
2
SiCl Ru: C, 40.00; H, 6.04; N, 4.67%. Found: C, 39.12; H, 6.01; N, 4.62%.
6
prior to use. [Ru(PPh
Cl)] , [Ru(NO)Cl ,xH
oxide), and [Ru(COD)Cl
3
)
3
Cl
2
], [Ru(CO)
2
Cl
Cl
2
]
n
, [(
h -p-cymene)RuCl(m-
2
3
2
O], [Ru(DMSO)
4
2
] (DMSO ¼ dimethyl sulf-
6
2-O,N-L1)] (2)
2
.3.2. Synthesis of [(
To a slurry solution of [(
.08 mmol) and AgNO (27.1 mg, 0.16 mmol) in CH
3
h -p-cymene)RuCl(k
2
]
x
(COD ¼ 1,5-cyclooctadiene) were pre-
6
h
-p-cymene)RuCl(
m-Cl)]
2
(48.9 mg,
CN (10 mL)
pared according to the literature methods [9e14]. Triethylamine,
0
3
salicylaldehyde, 5-chloro-salicylaldehyde, 3,5-(di-tert-butyl)salicy-
was added a solution of ligand L1H (52.1 mg, 0.16 mmol) and Et
3
N
1
laldehyde,
g
-aminopropyltriethoxysilane, and N -[3-(trimethox-
(ca. 0.1 mL) in THF (5 mL). The mixture solution was stirred at
ysilyl)-propyl]ethane-1,2-diamine were purchased from Alfa Aesar
Ltd. and used as received. NMR spectra were recorded on a Bru-
room temperature for 15 min, resulting in a yellow solution with a
white precipitate. The precipitate was removed by filtration. The
clear solution was stirred at room temperature for additional 2 h,
during which a color changed gradually from yellow to red. The
solvent was removed by vacuum, and the residue was washed
1
kerALX400 spectrometer operating at 400 and 162 MHz for H and
3
1
P, respectively. Chemical shifts (d, ppm) were reported with
1
31
reference to SiMe
recorded on
Elemental analyses were carried out using a Perkin-Elmer 2400
CHN analyzer. N adsorption/desorption isotherms were obtained
4
( H) and 85% H
3 4
PO ( P). Infrared spectra were
a
Perkin-Elmer 16 PC FT-IR spectrophotometer.
with diethyl ether (5 mL ꢂ 3). Recrystallization from CH
2
Cl
2
/n-
6
2
hexane (1:3) gave red block crystals of [(
h
-p-cymene)- RuCl(k -
2
O,N-L1)] (2). The solid product was collected and dried in air.
at 77 K with a Micromeritics ASAP 2020MþC system after the
ꢀ1
Yield: 87.5 mg, 92%. IR (KBr disc, cm ):
n
CꢀH ¼ 2933(s), 1442(w),
ꢁ
samples were first degassed at 120 C for 6 h. TEM images were
1
368(s),
n
C¼N ¼ 1628(s),
n
C¼C ¼ 1569(m), 784(m),
n
CꢀN ¼ 1457(s),
collected on a JEM-2100 electron microscope at 200 kV. Gas chro-
matography analyses were performed with an FID detector on a
Shimadzu GC-2010 Plus spectrometer using the RTX-5 column.
1
nSiꢀO ¼ 1071(s),
n
SiꢀC ¼ 1262(s). H NMR (CDCl
3
, ppm): 8.11 (s, 1H,
CH¼N), 7.39e7.07 (m, 8H, -Ar), 3.87e3.80 (m, 6H, O-CH
2
),
3
3
0
5
.74e3.67 (m, 2H, N-CH
H, C -CH ), 1.74e1.70 (m, 2H, CH
.64e0.58 (m, 2H, Si-CH ). Anal. Calc. for C26
2.46; H, 6.77; N, 2.35%. Found: C, 52.38; H, 6.73; N, 2.33%.
2
), 2.92e2.85 (m, 1H, -CH(CH
3
)
2
), 2.32 (s,
6
H
4
3
2
), 1.29e1.12 (m, 15H, CH
3
),
2
2
.2. Syntheses of ligands
2
4
H40NO SiClRu: C,
.2.1. General procedure
Salicylaldehyde (1.80 mmol) and g-aminopropyl- triethoxysilane
2
.3.3. Synthesis of [(
The method was similar to that used for 2, employing ligand
L2H (65.7 mg, 0.18 mmol) instead of L1H. Yield: 99 mg, 90%. IR
h k
6-p-cymene)RuCl( 2-O,N-L2)] (3)
(
0.41 g, 1.80 mmol) in 20 mL ethanol solution was carried out with
ꢁ
stirring at 85 C for 2 h. Upon cooling to room temperature, the solvent
was removed with rotary evaporator. The crude product (yellow oil)
ꢀ1
(KBr disc, cm ):
n
CꢀH ¼ 2936(s), 1441(w), 1362(s),
n
n
C¼N ¼ 1624(s),
SiꢀO ¼ 1074(s),
, ppm): 8.21 (s, 1H, CH¼N),
), 3.72e3.62 (m,
), 2.23 (s, 3H, C -CH ),
), 1.28e1.11 (m, 15H, CH ), 0.68e0.59 (m, 2H,
). Anal. Calc. for C26 SiCl Ru: C, 49.40; H, 6.24; N,
was dried in vacuum to afford the desired Schiff-base ligands in
1
n
n
C¼C ¼ 1572(m),
788(m),
n
CꢀN ¼ 1462(s),
excellent yields (ca. > 95%). For L1H: H NMR (CDCl
3
, ppm): 8.74 (mbr,
), 3.82e3.75 (m,
), 1.81e1.72 (m, 2H, CH ),
SiꢀC ¼ 1261(s). 1H NMR (CDCl
3
1
6
1
n
H, OH), 8.31 (s, 1H, CH¼N), 7.29e6.83 (m, 4H, C
6 4
H
7.63e6.80 (m, 7H, -Ar), 3.83e3.76 (m, 6H, O-CH
2
H, O-CH
2
), 3.58e3.50 (m, 2H, N-CH
2
2
ꢀ
1
2H, N-CH
2
), 2.84e2.78 (m, 1H, -CH(CH
3
)
2
6
H
4
3
.22e1.10 (m, 9H, CH
3
), 0.67e0.60 (m, 2H, Si-CH
2
). IR (KBr disc, cm ):
C¼C ¼ 1553(m),
1.83e1.76 (m, 2H, CH
2
3
CꢀH ¼ 2914(s), 1457(w), 1369(s),
n
C¼N ¼ 1628(s),
n
1
Si-CH
2
2
H39NO
4
2
7
91(m), CꢀO ¼ 1312(s). For L2H: H NMR (CDCl
nSiꢀO ¼ 1082(s),
n
3
,
.22%. Found: C, 49.16; H, 6.33; N, 2.26%.
ppm): 8.79 (mbr,1H, OH), 8.22 (s,1H, CH¼N), 7.21e6.84 (m, 3H, C
H
6 3
),
), 1.80e1.73 (m,
), 0.64e0.54 (m, 2H, Si-CH ). IR (KBr
3
2
.80e3.72 (m, 6H, O-CH
2 2
), 3.57e3.51 (m, 2H, N-CH
H, CH ), 1.22e1.10 (m, 9H, CH
2
3
2
2.3.4. Synthesis of (Et
3
NH)[RuCl
To a slurry solution of [Ru(CO)
2
(CO)
Cl
2
(
k
2-O,N-L3)] (4)
(45.6 mg, 0.2 mmol) in THF
ꢀ1
disc, cm ):
n
CꢀH ¼ 2925(s), 1437(w), 1366(s),
n
C¼N ¼ 1618(s),
2
2
]
n
1
n
C¼C ¼ 1565(m), 790(m),
n
SiꢀO ¼ 1070(s),
nCꢀO ¼ 1296(s). For L3H: H
(10 mL) was added a solution of ligand L3H (84.0 mg, 0.2 mmol) and
Et N (ca. 0.1 mL) in THF (5 mL). The mixture solution was stirred at
reflux for 4 h, resulting in a yellow solution. The solvent was
NMR (CDCl
3
, ppm): 8.69 (mbr, 1H, OH), 8.32 (s, 1H, CH¼N), 7.52e7.48
3
(
1
m, 2H, C H
6 2
), 3.71e3.63 (m, 6H, O-CH
2
), 3.45e3.36 (m, 2H, N-CH
), 0.65e0.60 (m, 2H, Si-CH
CꢀH ¼ 2935(s), 1445(w), 1371(s),
C¼C ¼ 1561(m), 778(m), SiꢀO ¼ 1070(s), CꢀO ¼ 1310(s).
2
),
).
.72 (s, 18H, C-CH
IR (KBr disc, cm ):
3
),1.35e1.29 (m, 9H, CH
3
2
removed by vacuum, and the residue was washed with diethyl
ꢀ
1
n
nC¼N ¼ 1635(s),
ether (5 mL ꢂ 3). Recrystallization from CH
2
Cl
2
/n-hexane (1:4) gave
-O,N-L3)] (4). The solid
product was collected and dried in air. Yield: 105 mg, 81%. IR (KBr
2
n
n
n
3 2 2
yellow crystals of (Et NH)- [RuCl (CO) (k
ꢀ
1
2
.3. Syntheses of ruthenium Schiff base complexes functionalized
with alkoxysilyl groups
disc, cm ):
1998(vs),
C¼N ¼ 1620(s),
SiꢀO ¼ 1071(s),
CH¼N), 7.51e7.48 (m, 2H, C
3.45e3.36 (m, 2H, N-CH ), 1.72 (s, 18H, C-CH
CH ), 0.66e0.60 (m, 2H, Si-CH ). Anal. Calc. for C32
C, 50.12; H, 7.62; N, 3.65%. Found: C, 50.24; H, 7.55; N, 3.69%.
n
CꢀH ¼ 2932(s), 1448(w), 1366(s),
n
n
C≡O ¼ 2017(vs),
n
n
C¼C ¼ 1576(m), 782(m),
CꢀN ¼ 1459(s),
1
n
n
SiꢀC ¼ 1268(s). H NMR (CDCl
3
, ppm): 8.30 (s, 1H,
),
), 1.36e1.29 (m, 9H,
SiCl Ru:
2
.3.1. Synthesis of [RuCl
Solution of ligand L1H (32.6 mg, 0.10 mmol) in THF (5 mL) was
added a solution of [Ru(NO)Cl ,xH O] (23.7 mg, 0.10 mmol) in THF
15 mL). To the mixture was added two drops of Et N (ca. 0.2 mL).
2
(NO)(
k
2-O,N-L1)(OEt
2
)] (1)
6 2 2
H ), 3.70e3.60 (m, 6H, O-CH
2
3
3
2
3
2
H
58
N
2
O
6
2
(
3

A.-Q. Jia et al. / Journal of Organometallic Chemistry 855 (2018) 33e43
35
2
.3.5. Synthesis of [Ru(PPh
3
)
2
Cl
2
(
k
2N-L4)],CH
2
Cl
2
(5,CH
2
Cl
2
)
0.22 mmol) were mixed in toluene (15 mL), and then the mixture
was refluxed for 4 h during which a color changed from red to dark
red. The solvent was removed by vacuum, and the residue was
1
[
Ru(PPh Cl ] (106.6 mg, 0.11 mmol) and N -(3-(trimethoxysilyl)
3
)
2
2
propyl)ethane-1,2-diamine (L4) (25.2 mg, 0.11 mmol) were dissolved
in THF (15 mL), and the mixture was refluxed for 4 h during which a
color changed from brown to dark red. The solvent was removed by
vacuum, and the residue was washed with diethyl ether (5 mL ꢂ 3).
washed with diethyl ether (5 mL ꢂ 3). Recrystallization from CH
2
Cl
N-L4)] (7). The
solid product was collected and dried in air. Yield: 77 mg, 68%. IR
2
/
2
2
n-hexane (1:5) gave red crystals of [Ru(COD)Cl (k
ꢀ
1
Recrystallization from CH
crystals of [Ru(PPh
2
Cl
k
2
/n-hexane (1:5) gave brownish red
(KBr disc, cm ):
1620(s), 830(m),
SiꢀO ¼ 1078(s),
n
CꢀH ¼ 2928(s), 1447(w), 1376(s),
n
NꢀH ¼ 3450(m),
CꢀN ¼ 1458(s),
3
, ppm): 4.34e4.08
2
3 2 2
) Cl (
N-L4)],CH
2 2
Cl
(5,CH
2 2
Cl ). The solid
n
C¼C ¼ 1570(m), 785(m),
n
1
product was collected and dried in air. Yield: 87.8 mg, 85%. IR
n
nSiꢀC ¼ 1278(s). H NMR (CDCl
ꢀ1
(
1
n
3
(
CH
SiCl
5
KBr disc, cm ):
625(s), 822(m),
SiꢀO ¼ 1075(s),
0H, P-Ph), 3.57 (s, 9H, O-CH
m, 3H, NH and NH), 1.57e1.50 (m, 2H, CH
); P NMR (CDCl , ppm): 28.5, 29.7. Anal. Calc. for C44
Ru,(CH Cl ): C, 53.84; H, 5.42; N, 2.79%. Found: C, 53.76; H,
.47; N, 2.83%.
n
CꢀH ¼ 2930(s), 1440(w), 1370(s),
n
NꢀH ¼ 3445(m),
(m, 4H, CH¼CH), 3.56 (s, 9H, O-CH
2.20e1.85 (m,11H, NH , NH, and CH in COD),1.57e1.46 (m, 2H, CH
0.56e0.47 (m, 2H, Si-CH ). Anal. Calc. for C16 SiCl
38.24; H, 6.82; N, 5.57%. Found: C, 38.11; H, 6.75; N, 5.52%.
3
), 2.95e2.40 (m, 6H, N-CH
2
),
),
n
C¼C ¼ 1565(m), 780(m),
n
CꢀN ¼ 1455(s),
2
2
2
1
n
SiꢀC ¼ 1268(s). H NMR (CDCl
3
, ppm): 7.89e7.43 (m,
), 2.20e1.86
2
), 0.58e0.50 (m, 2H, Si-
2
H N O
34 2 3
2
Ru: C,
3 2
), 2.95e2.40 (m, 6H, N-CH
2
31
2
3
52 2 3-
H N O
2.4. X-Ray crystallography
P
2 2
2
2
Crystallographic data and experimental details for ruth-
2
6
enium(II) complexes [RuCl
2
(NO)(
h
k
-O,N-L1)(OEt
-p- cymene)RuCl(
(4), [Ru(PPh
N-L4)] (6), and [Ru(COD)
N-L4)] (7) are summarized in Table 1. Intensity data were
collected on a Bruker SMART APEX 1000 CCD diffractometer using
graphite-monochromated Mo K radiation (
2
)] (1), [(
h
-p-
2
.3.6. Synthesis of [Ru(DMSO)
Ru(DMSO) Cl ] (58.1 mg, 0.12 mmol) and ligand L4 (28.0 mg,
.12 mmol) was mixed in THF (15 mL), and the solution was refluxed
2
Cl
2
(
k
2N-L4)] (6)
2
6
2
cymene)RuCl(
Et NH)[RuCl
CH Cl (5,CH
Cl
k
-O,N-L1)] (2), [(
k -O,N-L2)] (3),
) Cl (k N-L4)],-
3 2 2
[
4
2
2
2
(
3
2
(CO)
2
(
k
-O,N-L3)]
0
2
2
2
2
Cl ), [Ru(DMSO) Cl (k
2
2 2
for 4 h during which a color changed from yellow to red. The solvent
was removed by vacuum, and the residue was washed with diethyl
2
2
(k
ether (5 mL ꢂ 3). Recrystallization from CH
2
Cl
2
/n-hexane (1:5) gave
a
l
¼ 0.71073 Å). The
2
red crystals of [Ru(DMSO)
collected and dried in air. Yield: 33 mg, 48%. IR (KBr disc, cm ):
2 2
Cl (k N-L4)] (6). The solid product was
data were corrected for absorption using the program SADABS [15].
ꢀ
1
Structures were solved by Direct Methods and refined by full-
n
n
n
CꢀH ¼ 2933(s), 1445(w), 1368(s),
n
NꢀH ¼ 3440(m), 1610(s), 836(m),
CꢀN ¼ 1453(s), SiꢀO ¼ 1068(s),
, ppm): 3.59 (s, 9H, O-CH ), 2.91e2.43
), 2.34 (s, 12H, S-CH ), 2.21e1.89 (m, 3H, NH and NH),
), 0.58e0.49 (m, 2H, Si-CH ). Anal. Calc. for
2
matrix least-squares on F using the SHELXTL software package
C¼C ¼ 1578(m), 795(m),
n
n
[16]. All non-hydrogen atoms were refined anisotropically. The
1
SiꢀC ¼ 1270(s). H NMR (CDCl
3
3
positions of all hydrogen atoms were generated geometrically
(
m, 6H, N-CH
2
3
2
(
C
sp3eH ¼ 0.96 Å, Csp2eH ¼ 0.93 Å and NeH ¼ 0.86 Å), assigned
1.59e1.49 (m, 2H, CH
2
2
isotropic thermal parameters, and allowed to ride on their
C
6
12 34 2 5 2 2
H N O SiCl S Ru: C, 26.18; H, 6.22; N, 5.09%. Found: C, 26.29; H,
respective parent carbon atoms before the final cycle of least-
squares refinement. In 5,CH Cl , the CH Cl solvent was refined
2 2 2 2
.31; N, 5.03%.
with the bond distance restraints due to relatively high thermal
factors of two chloride atoms, which may result in the relatively
large R1(wR2) values.
2
(k
2N-L4)] (7)
2
.3.7. Synthesis of [Ru(COD)Cl
[
Ru(COD)Cl (62.2 mg, 0.22 mmol) and ligand L4 (51.2 mg,
2 x
]
Table 1
Crystallographic data and experimental details for [Ru(L1)(NO)Cl
2
(OEt
2
] (6), and [(cod)Ru(L4)Cl ] (7).
2
)] (1), [(cymene)Ru(L1)Cl] (2), [(cymene)Ru(L2)Cl] (3), (Et
3
NH)[Ru(L3)(CO)
2
2 3 2
Cl ] (4), [Ru(L4)(PPh ) Cl],
CH
2
Cl
2
(5,CH
2
Cl
2
), [Ru(L4)(DMSO)
2
Cl
2
Compound
1
2
3
4
5,CH
Cl
2 2
6
7
empirical formula
formula weight
crystal system
a (Å)
b (Å)
c (Å)
C
20
H
36
N
2
O
6
SiCl
2
Ru
C
26
H
40NO
4
SiClRu
C
26
H
39NO
4
2
SiCl Ru
C
32
H
58
N
2
O
6
SiCl
2
Ru
C
45
H
54
N
2
O
3
SiCl
4
P
2
Ru
C
12 34 2 5 2 2 16 34 2 3 2
H N O SiCl S Ru C H N O SiCl Ru
600.57
triclinic
595.20
monoclinic
28.41(3)
7.802(8)
12.787(12)
629.64
orthorhombic
12.971(3)
8.1325(16)
28.017(5)
766.86
monoclinic
17.3691(11)
14.3285(9)
17.9466(11)
1003.80
trigonal
44.710(6)
550.59
triclinic
8.7833(13)
10.9538(16)
12.7730(19)
103.912(2)
101.906(2)
98.734(2)
1140.6(3)
P-1
502.51
triclinic
9.7857(11)
10.9909(12)
11.1992(13)
111.707(1)
96.640 (1)
98.892(1)
1085.9(2)
P-1
10.3115(15)
12.4954(18)
12.5051(18)
88.915(2)
67.735(2)
71.249(2)
1402.2(4)
P-1
12.9277(19)
ꢁ
a
b
g
( )
ꢁ
( )
92.552(13)
2831(5)
112.597(2)
4123.5(4)
ꢁ
( )
3
V (Å )
2955.3(10)
Pca2
22380(6)
R-3
space group
P2
1
/c
1
P2
1
/n
Z
D
2
4
4
4
18
1.341
296(2)
9324
0.657
2
2
calc (g cm 3
ꢀ
)
1.422
296(2)
620
0.826
8753
6180
1.396
296(2)
1240
0.721
17317
6549
1.415
296(2)
1304
0.782
17379
5377
1.235
296(2)
1616
0.577
26961
9329
1.603
296(2)
568
1.180
7048
4992
1.040
296(2)
520
1.040
6820
temperature (K)
F(000)
m
) (mm 1
ꢀ
)
(Mo-K
a
total refln
independent refln
35778
8701
4828
parameters
294
314
322
413
537
233
230
R
int
a
0.0175
(I)) 0.0447, 0.1080
0.0504
0.0542
0.0522
0.0609, 0.1484
0.1474, 0.1920
0.995
0.2244
0.0860, 0.2030
0.1334, 0.2300
0.906
0.0163
0.0381, 0.0937
0.0459, 0.0999
1.038
0.0165
b
R1 , wR2 (I > 2
R1, wR2 (all data)
GoF
s
0.0436, 0.0996
0.0961, 0.1230
0.995
0.0413, 0.0876
0.0801, 0.1039
1.005
0.0363, 0.0752
0.0499, 0.0829
1.012
0.0683, 0.1240
1.025
c
Flack parameter
e
e
0.02(4)
e
e
e
e
a
R1 ¼ rrF
o
r e rF
c
rr/rF
o
r.
b
c
2
2
2
2
r2]1/2.
wR2 ¼ [w(rF
GoF ¼ [w(rF
o
r e rF
r e rF
c
r) /wrF
o
r) /(Nobs e Nparam)]1/2
2
o
c
.

36
A.-Q. Jia et al. / Journal of Organometallic Chemistry 855 (2018) 33e43
2
.5. Immobilization of Ru alkoxysilyl complexes 2 and 5 anchored
precursors 2 or 5 or heterogeneous catalyst precursors (2)/SBA-15
or (5)/SBA-15 (0.02 mmol Ru) and CH Cl (10 mL). The resulting
onto SBA-15
2
2
suspension was stirred at room temperature for the appropriate
times (0.5 h, 1 h, 3 h, 10 h and 20 h). The resulted mixture was
filtered, and the filtrate was characterized by gas chromatography
using chlorobenzene as internal standard.
1
g SBA-15 was introduced into a three-necked flask connected
to a vacuum pump and heated at 473 K for 4 h in order to remove
the water and air adsorbed on the surface. 20 mg Complex 2 or 5
2
were dissolved in toluene which was degassed with N bubbling for
1
5 min. The activated SBA-15 was suspended into the above solu-
3
. Results and discussion
tion, and the mixture was stirred at room temperature for 6 h. The
excess toluene was removed using a rotary evaporator, and the
resulting yellow solid was dried at 80 C overnight. The product
was washed with toluene and diethyl ether until the filtrate
became colorless. Finally the brown solid products (2)/SBA-15 and
3.1. Preparation and characterization of free ligands and ruthenium
ꢁ
complexes
Condensation of
2 2 3 3
g-aminopropyltriethoxysilane H N(CH ) Si(OEt)
(5)/SBA-15 were dried in vacuo for 2 h and stored for further ap-
with salicylaldehyde, 5-chloro-salicylaldehyde, or 3,5-(di-tert-butyl)-
salicylaldehyde in refluxing ethanol for 2 h easily afforded bidentate
Schiff-base ligands L1H, L2H and L3H, respectively (Scheme 1).
As shown in Scheme 2, reaction of ruthenium nitrosyl trichloride
(C¼N)] cmꢀ ; for (5)/
1
plications. IR (KBr) for (2)/SBA-15: ṽ ¼ 1628 [
n
ꢀ
1
SBA-15: ṽ ¼ 1625 [
.6. Catalyst testing
n(NeH)] cm .
2
[Ru(NO)Cl
3 2 3
,xH O] and L1H in the presence of Et N in THF resulted a
2
typical ruthenium nitrosyl complex [RuCl
2
2
(NO)(k -O,N-L1)(OEt )] (1)
In a typical experiment, a testing tube was filled with benzyl
alcohol (1 mmol), TBHP (0.5 mmol), homogeneous catalyst
as red crystals. The deprotonated Schiff-base ligand L1 and a solvent
molecule diethyl ether coordinated to the ruthenium center to
0
Scheme 1. Syntheses of N,O-Schiff bases (L1H, L2H, L3H) and schematic representation of N,N -diamine ligand L4.
Scheme 2. Syntheses of ruthenium complexes 1e4 with N,O-bidentate Schiff-base ligands bearing ethoxysilyl groups.

A.-Q. Jia et al. / Journal of Organometallic Chemistry 855 (2018) 33e43
37
0
Scheme 3. Syntheses of ruthenium complexes 5e7 with N,N -bidentate diamine ligands bearing methoxysilyl groups.
replace one chloro ligand in [Ru(NO)Cl
band for ruthenium nitrosyl complex 1 is found at 1790 cm
3 2
,xH O]. The characteristic
ꢀ
1
(nN≡O) in
the IR spectrum, compared with that in a ruthenium nitrosyl species
ꢀ
ꢀ1
[Cl
5
Ru(NO)]2 (1843 cm ) [17], much lower than that of N¼O group
ꢀ1
in [Ru(NO)(PPh
) Cl
3 2 3
] (1881 cm ) [18]. The SiꢀO stretching vibration
ꢀ1
modes were found at 1075 cm , similar to that in the free ligand L1H
1082 cm ). Treatment of [(
L2H in the presence of two equiv. AgNO
ꢀ
1
6
(
h
-p-cymene)RuCl(
m
-Cl)]
2
with L1H or
N gave the
3
and excess Et
3
6
2
6
expected complexes [(
h
-p-cymene)RuCl(
-O,N-L2)] (3), respectively. The H NMR signals of
complexes 2 and 3 showed the methyl protons attached to -C
moiety at around 2.30 ppm as a singlet. Reaction of [Ru(CO) Cl and
L3H in the presence of Et N afforded an anionic ruthenium(II)
carbonyl complex (Et NH)[RuCl
crystals. The two terminal carbonyl C≡O stretching vibration modes
k -O,N-L1)] (2) or [(h -p-
2
1
cymene)RuCl(
k
6 4
H
2
2 n
]
3
2
3
2 2
(CO) (k -O,N-L3)] (4) as yellow
ꢀ
1
Fig. 2. Molecular structure of complex 2 showing the atom-labeling scheme, hydrogen
atoms are omitted for clarity. Thermal ellipsoids are drawn at the 35% probability level.
Selected bond lengths (Å) and bond angles (deg): Ru(1)-N(1) ¼ 2.091(4), Ru(1)-
Cl(1) ¼ 2.432(2), Ru(1)-O(1) ¼ 2.041(3), Ru(1)-C(18) ¼ 2.206(4), Ru(1)-C(19) ¼ 2.186(4),
were found at 2017 and 1998 cm in the IR spectrum of 4, and the
ꢀ
1
SiꢀO stretching vibration modes appeared at 1071 cm , which well
compared with the related ruthenium carbonyl complex bearing N,O-
Schiff base ligands functionalized with ethoxysilyl groups [19].
Ru(1)-C(20) ¼ 2.177(4),
Ru(1)-C(21) ¼ 2.197(4),
Ru(1)-C(22) ¼ 2.175(4),
Ru(1)-
1
C(23) ¼ 2.183(4), Si(1)-C(10) ¼ 1.817(6), Si(1)-O(2) ¼ 1.645(7), Si(1)-O(3) ¼ 1.629(5),
As shown in Scheme 3, reactions of N -(3-(trimethoxysilyl)
Si(1)-O(4) ¼ 1.617(6); O(1)-Ru(1)-N(1) 88.25(11), O(1)-Ru(1)-Cl(1) ¼ 84.91(10).
propyl)ethane-1,2-diamine (L4) and [Ru(PPh
3
)
3
2 2
Cl ], [Ru(DMSO)Cl ]
or [Ru(COD)Cl
ruthenium(II)
2 x
] in THF or toluene at reflux afforded the according
2
complexes
[Ru(PPh
3
)
2
Cl
2
(k
N-L4)]
(5),
Fig. 1. Molecular structure of complex 1 showing the atom-labeling scheme, hydrogen
atoms are omitted for clarity. Thermal ellipsoids are drawn at the 35% probability level.
Selected bond lengths (Å) and bond angles (deg): Ru(1)-N(1) ¼ 1.719(3), Ru(1)-
N(2) ¼ 2.074(3), Ru(1)-Cl(1) ¼ 2.3702(10), Ru(1)-Cl(2) ¼ 2.3722(12), Ru(1)-O(2) ¼ 1.949(3),
Ru(1)-O(6) ¼ 2.169(3), N(1)-O(1) ¼ 1.157(4), Si(1)-C(10) ¼ 1.829(4), Si(1)-O(3) ¼ 1.581(4),
Si(1)-O(4) ¼ 1.587(4), Si(1)-O(5) ¼ 1.614(5); O(2)-Ru(1)-N(2) 90.34(11), Cl(1)-Ru(1)-Cl(2)
Fig. 3. Molecular structure of complex 3 showing the atom-labeling scheme, hydrogen
atoms are omitted for clarity. Thermal ellipsoids are drawn at the 35% probability level.
Selected bond lengths (Å) and bond angles (deg): Ru(1)-N(1) ¼ 2.095(4), Ru(1)-
Cl(1) ¼ 2.4281(16), Ru(1)-O(1) ¼ 2.048(4), Ru(1)-C(18) ¼ 2.229(7), Ru(1)-C(19) ¼ 2.179(7),
Ru(1)-C(20) ¼ 2.163(5),
Ru(1)-C(21) ¼ 2.183(6),
Ru(1)-C(22) ¼ 2.185(6),
Ru(1)-
C(23) ¼ 2.187(6), Si(1)-C(10) ¼ 1.820(7), Si(1)-O(2) ¼ 1.625(6), Si(1)-O(3) ¼ 1.610(7), Si(1)-
174.25(4), N(2)-Ru(1)-O(6) 169.29(12), Ru(1)-N(1)-O(1) ¼ 177.2(4).
O(4) ¼ 1.609(6); O(1)-Ru(1)-N(1) 87.84(19), O(1)-Ru(1)-Cl(1) ¼ 84.63(12).

38
A.-Q. Jia et al. / Journal of Organometallic Chemistry 855 (2018) 33e43
[
Ru(DMSO)
2
Cl
2
(
k2N-L4)] (6) or [Ru(COD)Cl
2
(
k2N-L4)] (7), respec-
regions in the 1H NMR spectra. The highfield chemical shift
(~0.58 ppm) of -CH Si(OMe) protons in complexes 5e7 are near to
those of -CH Si(OEt)
stretching vibration modes appeared at around 1070 cm in the IR
spectra of complexes 5e7, similar to those in complexes 1e4.
3
1
tively, as red crystals in good yields. The P NMR spectrum of 5
displayed phosphorus resonances at 28.5 and 29.7 ppm, indicating
the two triphenylphosphine ligands are cis to each other. The
chemical shifts of methyl groups in DMSO ligands in 6 were found
at around 2.34 ppm, and the CH¼CH protons of COD ligand in 7
were observed in the 4.34e4.08 ppm regions. Moreover, the -NH/
2
3
2
3
protons in 1e4 (~0.68 ppm). The SiꢀO
ꢀ1
3.2. X-ray crystal structures of ruthenium complexes 1e7
2
NH groups in complexes 5e7 were observed in the 1.85e2.21 ppm
It was noted that crude products of complexes 1e7 were all
initially obtained as oily states, which could not be purified by
chromatograph over silica gel, due to the attachment of alkoxysilyl
groups on the expected targets. Many efforts have been performed
so as to obtain pure products of complexes 1e7 by repeatable
recrystallization under different conditions. Notwithstanding,
relatively high/good quality single-crystals of complexes 1e7 were
successfully obtained, although it was a quite hard work during our
experiments. The ORTEP representations of the molecular struc-
tures of them with selected bond distances and bond angles are
shown in Figs. 1e7, respectively. The central ruthenium atom in
complex 1 is bonded in a slightly distorted octahedral geometry, to
two terminal chlorides, two nitrogen atoms (one linear nitrosyl
ligand and the other one is imine nitrogen) and two oxygen atoms
(
one phenolic oxygen and one diethyl ether molecule). The RuꢀNNO
bond length is 1.719(3) Å and the N≡O bond length is 1.157(4) Å,
which are compared with those in other ruthenium(II) nitrosyl
complexes [18,20], e.g. [RuCl
3
(NO)(PPh
3
)
2
] (1.737(7) Å for RuꢀN,
1
.142(8) Å for N≡O). In addition, the RuꢀNꢀO bond angle is
ꢁ
177.2(4) , clearly indicating a linear N≡O coordination where
II
þ
Ru ꢀNO is the electronic structure. The RuꢀOEt2O bond length of
.169(3) Å is longer than that of RuꢀO(L1) (1.949(3) Å), presenting a
relatively weaker interaction. The RuꢀN(L1) bond length of
2
1
.949(3) Å and the average RuꢀCl bond length of 2.3712(11) Å are in
agreement with the corresponding bond parameters as described
for similarly constituted complexes [19,21]. The SiꢀC and average
SiꢀO bond lengths are 1.829(4) and 1.594(4) Å, respectively. The
ꢁ
bite angle of OꢀRuꢀN is 90.34(11) in complex 1. Complexes 2 and 3
could be formulated as
a six-coordinate ruthenium species
assuming the cymene moiety occupied three coordination sites, the
ꢁ
ꢁ
bite angles of OꢀRuꢀN are 88.25(11) and 87.84(19) in complexes
ꢁ
2
and 3, respectively, smaller than that in complex 1 (90.34(11) ). In
the anionic ruthenium complex 4, the ruthenium atom is
Fig. 4. (a) Molecular structure of complex 4 showing the atom-labeling scheme,
hydrogen atoms and the counter cation are omitted for clarity. Thermal ellipsoids are
drawn at the 35% probability level. Selected bond lengths (Å) and bond angles (deg):
Ru(1)-C(1) ¼ 1.838(9),
Ru(1)-C(2) ¼ 1.848(9),
Ru(1)-Cl(1) ¼ 2.4120(14),
Ru(1)-
Fig. 5. Molecular structure of complex 5 showing the atom-labeling scheme, hydrogen
atoms and the solvent are omitted for clarity. Thermal ellipsoids are drawn at the 35%
probability level. Selected bond lengths (Å) and bond angles(deg): Ru(1)-N(1) ¼ 2.149(5),
Ru(1)-N(2) ¼ 2.214(5), Ru(1)-Cl(1) ¼ 2.4250(18), Ru(1)-Cl(2) ¼ 2.4184(18), Ru(1)-
P(1) ¼ 2.3272(17), Ru(1)-P(2) ¼ 2.333(2), Si(1)-C(5) ¼ 1.824(7), Si(1)-O(1) ¼ 1.614(9),
Si(1)-O(2) ¼ 1.604(9), Si(1)-O(3) ¼ 1.549(9); N(1)-Ru(1)-N(2) ¼ 78.9(2), P(1)-Ru(1)-
P(2) ¼ 97.77(6), Cl(1)-Ru(1)-Cl(2) ¼ 164.08(7), N(2)-Ru(1)-P(1) ¼ 171.19(15), N(1)-Ru(1)-
P(2) ¼ 169.55(14).
Cl(2) ¼ 2.4291(16), Ru(1)-N(1) ¼ 2.065(4), Ru(1)-O(3) ¼ 2.031(4), O(1)-C(1) ¼ 1.071(8),
O(2)-C(2) ¼ 1.128(8), Si(1)-C(20) ¼ 1.791(7), Si(1)-O(4) ¼ 1.581(6), Si(1)-O(5) ¼ 1.560(6),
Si(1)-O(6) ¼ 1.576(9); N(1)-Ru(1)-O(3) ¼ 89.17(15), N(1)-Ru(1)-Cl(1) ¼ 173.26(13), C(1)-
Ru(1)-Cl(2) ¼ 178.4(3), C(2)-Ru(1)-O(3) ¼ 173.9(2), O(1)-C(1)-Ru(1) ¼ 178.3(7), O(2)-
C(2)-Ru(1) ¼ 176.1(9). (b) Packing diagram of anionic ruthenium complex 4 in a unit cell,
viewed along the crystallographic ac plane. CeH/Cl, NeH/Cl, and CeHCH¼N/Cl
intermolecular hydrogen bonds are shown as dashed lines.

A.-Q. Jia et al. / Journal of Organometallic Chemistry 855 (2018) 33e43
39
coordinated by two carbonyl groups, two chloro ligands and one k2
O,N Schiff-base ligand. The RuꢀC bond lengths are 1.838(9) and
.848(9) Å, which are compared with those in the already-known
-
The structures of ruthenium complexes 5ꢀ7 with k2N-L4 ligand
have similar geometry, the two chloro ligands are trans to each
ꢁ
1
other with the bond angles of CleRueCl being 164.08(7) in com-
ꢁ
ꢁ
ruthenium(II) carbonyl complexes [22]. The OeRueN bite angle of
plex 5, 174.40(3) in complex 6, and 159.07(3) in complex 7. The
ꢁ
ꢁ
ꢁ
the bidentate Schiff-base ligand is 89.17(15) , being slightly larger
bite angles of NeRueN are 78.9(2) in complex 5, 79.43(11) in
ꢁ
than those in other ruthenium(II) carbonyl complexes with Schiff-
complex 6, and 80.80(10) in complex 7, indicating the different
ꢁ
ꢁ
base ligands (87.49(10) ꢀ88.19(10) ) [20]. The crystal packing
neutral ligands of triphenylphosphine, DMSO and COD coordinated
to ruthenium centers have little effect on the bite angle of diamine
ligand L4. The RueN bond lengths are 2.149(5) and 2.214(5) Å in
complex 5, which are similar to those in complex 6 (2.128(3),
2.187(3) Å) and complex 7 (2.123(2), 2.173(3) Å). The average RueCl
bond length is 2.4217(18) Å in complex 5, compared well to those in
complex 6 (2.4072(9) Å) and complex 7 (2.4349(8) Å). Moreover,
the average RueP bond length of 2.330(2) Å in complex 5, RueS
bond length of 2.2495(9) Å in complex 6, and RueC bond length of
molecule of complex 4 is governed by the weak intermolecular
NeH/Cl and CeH/Cl hydrogen-bonding interactions between the
þ
anionic ruthenium moiety and the counter cation [Et
3
NH] , more-
over there is also hydrogen-bonding interactions of CeHCH¼N/Cl
between two ruthenium molecules as shown in Fig. 4(b).
2.213(3) Å in complex 7 are in good agreement with related
Fig. 6. (a) Molecular structure of complex
6 showing the atom-labeling scheme,
hydrogen atoms are omitted for clarity. Thermal ellipsoids are drawn at the 35% proba-
Fig. 7. (a) Molecular structure of complex 7 showing the atom-labeling scheme,
bility level. Selected bond lengths (Å) and bond angles(deg): Ru(1)-N(1) ¼ 2.128(3),
hydrogen atoms are omitted for clarity. Thermal ellipsoids are drawn at the 35% proba-
bility level. Selected bond lengths (Å) and bond angles(deg): Ru(1)-N(1) ¼ 2.123(2),
Ru(1)-N(2) ¼ 2.187(3),
Ru(1)-Cl(1) ¼ 2.4089(9),
Ru(1)-Cl(2) ¼ 2.4056(9),
Ru(1)-
S(1) ¼ 2.2462(10), Ru(1)-S(2) ¼ 2.2528(9), S(1)-O(4) ¼ 1.488(3), S(2)-O(5) ¼ 1.489(3),
Si(1)-C(5) ¼ 1.848(5), Si(1)-O(1) ¼ 1.534(6), Si(1)-O(2) ¼ 1.612(5), Si(1)-O(3) ¼ 1.586(5);
N(1)-Ru(1)-N(2) ¼ 79.43(11), S(1)-Ru(1)-S(2) ¼ 92.68(3), Cl(1)-Ru(1)-Cl(2) ¼ 174.40(3),
N(2)-Ru(1)-S(1) ¼ 168.32(8), N(1)-Ru(1)-S(2) ¼ 178.13(8). (b) Packing diagram of ruthe-
nium complex 6 in a unit cell, viewed along the crystallographic bc plane. NeH$$$ODMSO
and NeH/Cl intermolecular hydrogen bonds are shown as dashed lines.
Ru(1)-N(2) ¼ 2.173(3),
Ru(1)-Cl(1) ¼ 2.4253(8),
Ru(1)-Cl(2) ¼ 2.4445(8),
Ru(1)-
C(9) ¼ 2.225(3), Ru(1)-C(10) ¼ 2.218(3), Ru(1)-C(13) ¼ 2.204(3), Ru(1)-C(14) ¼ 2.206(3),
Si(1)-C(5) ¼ 1.839(3), Si(1)-O(1) ¼ 1.617(3), Si(1)-O(2) ¼ 1.618(3), Si(1)-O(3) ¼ 1.629(3);
N(1)-Ru(1)-N(2) ¼ 80.80(10), Cl(1)-Ru(1)-Cl(2) ¼ 159.07(3). (b) Packing diagram of
ruthenium complex 7 in a unit cell, viewed along the crystallographic bc plane. NeH/O
and NeH/Cl intermolecular hydrogen bonds are shown as dashed lines.

40
A.-Q. Jia et al. / Journal of Organometallic Chemistry 855 (2018) 33e43
0
ruthenium(II) PPh
3
/DMSO/COD complexes comprising N,N -
molecule of complex 7 is governed by the weak intermolecular
NeH/Cl and NeH/OSi(OMe) hydrogen-bonding interactions be-
tween the ruthenium molecules to form a one dimensional chain as
shown in Fig. 7(b).
diamine ligands [23]. Two kinds of hydrogen-bonding interactions
of NeH/Cl and NeH$$$ODMSO exist in the crystal packing molecule
of complex 6 as could be seen in Fig. 6(b). The crystal packing
0
Scheme 4. Immobilization of ruthenium complexes 2 and 5 with N,O- or N,N -bidentate ligand bearing alkoxysilyl group on SBA-15 by condensation.
Fig. 8. Infrared spectra of SBA-15 (a), (2)/SBA-15 (b) and (5)/SBA-15 (c).
Fig. 9. TEM images of SBA-15 (2)/SBA-15 (b) and (5)/SBA-15 (c).

A.-Q. Jia et al. / Journal of Organometallic Chemistry 855 (2018) 33e43
41
3.3. Preparation, characterization and application of SBA-15
supported ruthenium complexes
Immobilization of two typical ruthenium complexes 2 and 5
0
bearing N,O-Schiff base or N,N -diamine ligand functionalized with
alkoxysilane groups on mesoporous SBA-15 by condensation is
shown in Scheme 4, in the loading process, the organic silicon
group was connected with SBA-15 in the form of -Si-O-Si-, and one
of the silicon-group connected with the organometallic ruthenium
complex [24]. The supported ruthenium complexes were further
characterized by a series of methods such as IR, TEM and N
2
adsorption/desorption measurements. IR spectra of parent calcined
mesoporous SBA-15 and grafted samples show bands at 1206 and
ꢀ
1
7
94 cm , which are due to stretching vibrations of the mesoporous
framework (SieOeSi) [25], as could be seen in Fig. 8. The imine and
ꢀ
1
amine stretching vibrations around 1628 cm can be observed in
the grafted materials, evidencing the presence of the ruthenium
complexes in the channels of both mesoporous materials. More-
over, the well supported organic silicon ruthenium complexes were
also tested by TEM. The supported materials displayed the similar
ordered mesoporous structure compared with SBA-15 (Fig. 9). The
particles of the ruthenium complexes loaded on the channel cannot
be seen in the TEM images, however, the channel of unsupported
SBA-15 seemed clearly visible while the channel of (2)/SBA-15 and
(5)/SBA-15 was obviously unclear, which may be attributed the
loading of complexes 1 and 5 on the pore wall of SBA-15 [26].
The pore structures of SBA-15, (2)/SBA-15 and (5)/SBA-15 were
further detected by low pressure N
surement at 77 K, as displayed in Fig. 10. The characteristic shape of
the N sorption isotherms (type IV isotherm with an H1 hysteresis
loop) of (2)/SBA-15 and (5)/SBA-15 did not change. And the obvious
decrease of N uptakes and surface area indicated part of the
2
adsorption/desorption mea-
2
2
original pore structure of SBA-15 was occupied by the organic sil-
icon ruthenium complexes [27]. The pore width distributions of (2)/
SBA-15 (5.92 nm) and (5)/SBA-15 (5.98 nm) were smaller than that
of the bare SBA-15 (6.24 nm), an indicative of the ruthenium
complex occupied partial pore volume. Moreover, the BET surface
2
ꢀ1
2 ꢀ1
area are decreased from 695 m g (SBA-15) to 541 m g ((2)/
2
ꢀ1
SBA-15) or 550 m g ((5)/SBA-15). The above results were caused
by the loading of complexes 2 and 5 on the pore of SBA-15, which is
in accordance with the results of the TEM images.
Previously, Leung reported that alkylruthenium complexes with
-
2 3 4
CH SiMe groups anchored on SBA-15 by elimination of SiMe and
the Ru-grafted species could catalyze the oxidation of benzyl alcohol
with tert-butyl hydroperoxide (TBHP) in moderate yields (up to 70%)
[28]. Under this guidance, we took the study of heterogeneous ma-
terials (2)/SBA-15 and ((5)/SBA-15) for oxidation of benzyl alcohol
with TBHP as oxidant at room temperature. Treatment of benzyl
alcohol with (2)/SBA-15 and TBHP in CH Cl gave benzaldehyde
2 2
selectively in 65% yield in 10 h; no benzoic acid was detected. Longer
reaction time did not lead to improved yield. Similar yield of benz-
aldehyde were found with ((5)/SBA-15) as catalyst after 10 h of re-
action (62%), compared with the homogeneous tetradentate-Schiff-
base-ruthenium/NMO (NMO ¼ N-methylmorpholine- N-oxide)
catalytic system (yield up to 77%) [29]. However, the homogeneous
catalysts 2 and 5 here were less active than the corresponding
supported catalysts, giving yields of 22% and 26%. The immobilized
complex (2)/SBA-15 appeared to be reusable for four cycles for the
oxidation of benzyl alcohol; though longer reaction periods are
needed for reactions after the third cycle.
Fig. 10. N
2
sorption isotherms of SBA-15 (a), (2)/SBA-15 (b), and (5)/SBA-15 (c). The
insets were the corresponding pore size distribution curves.
afforded corresponding ruthenium(II) complexes 5e7 bearing k2N-
diamine ligand with trimethoxysilyl groups. The structures of
complexes 1e7 were unambiguously established by single-crystal
X-ray diffraction. Up to now, there are few reported ruthenium
complexes bearing organosilicone moieties according to CCDC
searching result [19,30]. Immobilization of two typical ruth-
enium(II) complexes 2 and 5 on SBA-15, and characterization of
In summary, three new bidentate Schiff-base compounds
functionalized with terminal triethoxysilyl groups were synthe-
sized. They were applied to the neutral and anionic ruthenium(II)
1
complexes 1e4. Reactions of N -[3-(trimethoxysilyl)-propyl]
ethane-1,2-diamine and different ruthenium starting materials

42
A.-Q. Jia et al. / Journal of Organometallic Chemistry 855 (2018) 33e43
n~ a, H. Moriwaki, T. Sato, V. Soloshonok, Asym-
these hybrid heterogeneous materials were studied by IR, TEM and
adsorption/desorption measurements. The grafted materials
[8] (a) A.E. Sorochinsky, J.L. Ace
metric synthesis of -amino acids via homologation of Ni(II) complexes of
glycine Schiff bases. Part 2: Aldol, Mannich addition reactions, deracemization
a
N
2
were employed as heterogeneous catalysts for oxidation of benzyl
alcohol to benzaldehyde and could be recycled several times.
Application of such organometallic chemistry of the surface-bound
Ru alkoxysilyl species for other organic transformation reactions is
underway in our laboratory.
and (S) to (R) interconversion of
1017e1033;
(
a-amino acids, Amino Acids 45 (2013)
b) A.E. Sorochinsky, J.L. Ace n~ a, H. Moriwaki, T. Sato, V.A. Soloshonok, Asym-
metric synthesis of
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glycine Schiff bases; Part 1: alkyl halide alkylations, Amino Acids 45 (2013)
691e718.
[
9] T.A. Stephenson, G. Wilkinson, New complexes of ruthenium(II) and (III) with
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Supplementary material
[
(NO)(k2-O,N-L1)(OEt
6-
Crystallographic data for [RuCl
2
2
)] (1), [(
h
2
6
2
p-cymene)RuCl(
3), (Et NH)[RuCl
CH Cl (5,CH Cl
Cl
lographic Data Center as supplementary publication nos. CCDC
577451e1577457, respectively. Copies of the data can be obtained
k
-O,N-L1)] (2), [(
h
-p-cymene)RuCl(
k
-O,N-L2)]
N-L4)],
2
2
(
3
2
(CO)
2
(k
-O,N-L3)] (4), [Ru(PPh
3
)
2
Cl
2
(
k
2
[11] M.A. Bennett, T.N. Huang, T.W. Matheson, A.K. Smith, Di-
m
-chloro-bis
-1-isopropyl-4- methyl-benzene)ruthenium(II)], Inorg. Synth. 21
1982) 75.
2
2
2
2
), [Ru(DMSO)
2
Cl
2
(k
N-L4)] (6), and [Ru(COD)
6
[
(
chloro(h
2
2
(k N-L4)] (7) have been deposited with the Cambridge Crystal-
[12] A.A. Batista, C. Pereira, S.L. Queiroz, L.A.A. Oliveira, R.H.A. Santos,
M.T.P. Gambardella, Nitrosyl ruthenium complexes with general formula
1
[
RuCl
3
(NO)(P-P)] (P-P ¼ {PPh
2
(CH
(NO){PPh
2
)nPPh
2
(CH
}, n ¼ 1-3 and {PPh
2
-CH¼CH-PPh
2
}).
free of charge on application to CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK [fax: (þ44)1233-336-033; e-mail: deposit@ccdc.cam.
ac.uk].
X-ray structure of [RuCl
3
2
2
)
3
PPh }], Polyhedron 16 (1997)
2
927e931.
[
13] E. Alessio, G. Mestroni, G. Nardin, W.M. Attia, M. Calligaris, G. Sava, S. Zorzet,
Cis- and trans-dihalotetrakis(dimethyl sulfoxide)ruthenium(II) complexes
(
RuX
2
(DMSO)
4
; X ¼ Cl, Br): synthesis, structure, and antitumor activity, Inorg.
Acknowledgements
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[
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