A TiO2 immobilized Ru(ii) polyazine complex: A visible-light active photoredox catalyst for oxidative cyanation of tertiary amines

Article abstract of DOI:10.1039/c3ta14783e

A chemically functionalized nanocrystalline TiO₂ grafted ruthenium(ii) polyazine complex was found to be an efficient visible light photoredox catalyst for the oxidative cyanation of tertiary amines to the corresponding α-aminonitriles in high to excellent yields, using molecular oxygen as an oxidant and sodium cyanide in acetic acid as a cyanide source. The developed photoredox catalyst could be easily recovered by simple filtration and reused for several runs with consistent catalytic activity.

Full text of DOI:10.1039/c3ta14783e

View Article Online
View Journal
Journal of
Materials Chemistry A
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: S. L. Jain, P.
Kumar and S. Verma, J. Mater. Chem. A, 2014, DOI: 10.1039/C3TA14783E.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/materialsA

Page 1 of 6
CREATED USING THE RSC COMMJUNoICuArTnIOaNlToEMfPMLAaTEte(VrEiRa.l3s.1)C- ShEeE mWWiWs.tRrSyC.AORG/ELECTRONICFILES FOR DETAILS
View Article Online
DOI: 10.1039/C3TA14783E
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
TiO2 immobilized Ru(II) polyazine complex: a visibleꢀlight active
photoredox catalyst for oxidative cyanation of tertiary amines.
Pawan Kumar, Sanny Varma and Suman L. Jaina*
Received (in XXX, XXX) Xth XXXXXXXXX 200X, Accepted Xth XXXXXXXXX 200X
First published on the web Xth XXXXXXXXX 200X
DOI: 10.1039/b000000x
5
reported [Ir(ppy)2bpy]PF6 as a visible light photoredox catalyst
Chemically functionalized nanocrystalline TiO2 grafted ruthenium
(II) polyazine complex was found to be an efficient visible light
photoredox catalyst for the oxidative cyanation of tertiary amines to
10 the corresponding αꢀaminonitriles in high to excellent yields using
molecular oxygen as oxidant and sodium cyanide in acetic acid as a
cyanide source. The developed photoredox catalyst could be easily
recovered by simple filtration and reused for several runs with
consistent catalytic activity.
for aerobic oxidative cyanation of tertiary amines.8 However
55 difficult recovery and nonꢀrecyclability of the catalyst makes this
method of limited synthetic utility.
In continuation to our recent research programme on photo
catalysis, we herein report an efficient, heterogeneous, easily
recoverable and recyclable visible light active TiO2 immobilized
60 ruthenium polyazine photoredox catalyst for the oxidative
cyanation of tertiary amines using molecular oxygen as oxidant
and NaCN in acetic acid as a cyanide source (Scheme 1).
15 The use of visible light sensitization as a means to initiate
organic reactions is an attractive tool as the visible light is
ubiquitous, renewable and clean source of energy.1 Furthermore,
lack of visible light absorbance by organic compounds hinders
the possibilities of side reactions often associated with
20 photochemical reactions conducted with high energy UV light.
Among these, the use of photoredox catalysts in particular
Ru(II)polypyridine complexes for organic transformations are of
notable importance due to their ease of synthesis, stability at
room temperature, and excellent photoredox properties.2
25 However, similar to the homogeneous catalysis, these complexes
also suffer from the drawbacks of tedious recovery and nonꢀ
recycling ability of the catalyst. One of the elegant approaches
for making these catalysts recyclable is to fix the homogeneous
metal complexes to solid matrix. In the recent decades,
30 modification of titanium dioxide via immobilization or
functionalization with metal complexes has become an appealing
approach as these immobilized metal complexes can harvest
visible light and inject photogenerated electrons into the
conduction band of the titania.3
Scheme 1: Visible light active photoredox catalyst for the oxidative
65
cyanation of tertiary amines
Synthesis and characterization of the catalyst 2
During the present investigation, nanocrystalline TiO2 was
prepared by following the literature procedure.9 Hydroxyl groups
placed on TiO2 were targeted for grafting of ruthenium polyazine
35 αꢀAminonitriles are highly useful and versatile intermediates for
a wide range of natural products and nitrogen containing
bioactive compounds such as alkaloids.4 Also these compounds
show dual reactivity as the nucleophilic addition provides an
easy access to various compounds such as αꢀamino aldehydes,
40 ketones and βꢀamino alcohols. On the other hand, these
compounds can be easily hydrogenated to useful compounds 1,2ꢀ
diamines.5 The most common method for their synthesis also
known as Strecker reaction is well documented in the literature,
albeit consisting of multistep synthesis.6 An alternative and more
45 convenient approach for the preparation of these structural
motifs is the catalytic oxidative cyanation of sp3 CꢀH bonds
adjacent to the nitrogen atoms in tertiary amines. In this context,
a number of metal catalysts including Ru, Fe, V etc. in the
presence of stoichiometric oxidants such as mꢀchloroperbenzoic
50 acid, tertꢀbutyl hydroperoxide, O2, H2O2 has been reported.7
However, scanty reports are known on the use of photoredox
catalysts for this transformation. In this regard, Rueping et al
70 complex by using 3ꢀchloropropyltrimethoxysilane (CPTS) as a
coupler. The strategy opted for the synthesis of TiO2
immobilized rutheniumꢀpolyazine photocatalyst is shown in
Scheme 2.
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 1

Journal of Materials Chemistry A
Page 2 of 6
View Article Online
DOI: 10.1039/C3TA14783E
40
Fig. 1: XRD pattern of a) TiO2; b) TiO2 grafted Ruꢀpolyazine photocatalyst
2; c) Ruꢀpolyazine complex
The size and morphology of the samples were analyzed by SEM
and TEM measurements. The SEM image of the TiO2 and
45 photocatalyst 1 are given in supporting information.
.
Scheme 2: Synthesis of nanocrystalline TiO2 immobilized ruthenium
polyazine complex 2
TEM image (Fig. 2) revealed that the product consisted of the
homogeneous distribution of ruthenium over TiO2 support and
showed the particle size 10ꢀ20 nm. The black particles visible in
TEM image (Fig. 2a) are might be attributed to the presence of
50 ruthenium, which is further confirmed by EDX. Furthermore,
selected area electron diffraction (SAED) analysis was carried
out to identify the crystalline phases of TiO2 (Fig. 2b)
The successful synthesis of nanocrystalline TiO2 and TiO2
grafted ruthenium polyazine complex 2 were confirmed by
various techniques including XRD, SEM, TEM, ICPꢀAES,
CHNS, UVꢀVis, NMR, 13C NMR and FTIR spectroscopy.
Characterization data of the catalyst are given in the supporting
information. The values of BET surface area and BJH pore
10 volume of 2 as determined by nitrogen adsorption were found to
be 26.50 m2 g−1 and 0.0622 cm3 g−1, respectively (Supporting Fig
S3).
5
The crystallinity of the asꢀsynthesized TiO2 and TiO2ꢀRu(II)
polyazine photocatalyst 2 was examined by XRD10 analysis (Fig.
15 1). As shown in Fig 1a, the well resolved peaks and their
intensity revealed the good crystallinity of the TiO2 mainly in
anatase phase and the rutile form was present only in a small
quantity. The peaks at 2θ values of 24.86, 37.41, 47.68, 54.23,
54.51, 63.33, 69.48, and 73.69 were identified by comparison
20 with literature data and confirmed the successful synthesis of
TiO2 nanoparticles with anatase structure. The as synthesized
TiO2 was combined with phenanthrolineꢀ5ꢀamine ligands
followed by its reaction with ruthenium pyridyl complex
(Scheme 2). The XRD pattern of the TiO2 immobilized
25 ruthenium polyazine complex 2 is shown in Fig 1b. For the
comparison purpose we also prepared homogeneous ruthenium
polyazine complex by combining the ruthenium pyridyl complex
with phenanthrolineꢀ5ꢀamine ligand. The XRD pattern of the
homogeneous ruthenium complex is shown in Fig. 1c. As shown,
30 the XRD pattern of TiO2 immobilized ruthenium photocatalyst
(Fig 1b) exhibits combination of peaks originated from TiO2
(Fig. 1a) and ruthenium polyazine complex (Fig. 1c).
Importantly, no impurity peaks appeared in the diffractogram of
the synthesized photocatalyst 2 except for those of anatase TiO2
35 and ruthenium polyazine complex. Furthermore appearance of
ruthenium polyazine complex peaks in the XRD pattern of 2
confirmed the successful attachment of ruthenium complex to
TiO2. Furthermore, deposition of Ru(II)ꢀpolyazine onto the TiO2
did not affect the morphology of the TiO2 support (Fig 1b).
Fig. 2: a) TEM image of TiO2ꢀgrafted photocatalyst 2; b) SEAD image; c)
55
EDX
The catalytic efficiency of the as synthesized photocatalyst 2
was examined for the oxidative cyanation of tertiary amines 1 to
αꢀaminonitriles 3 with molecular oxygen in the presence of
NaCN and acetic acid using methanol as solvent under visible
60 irradiation, using a household white LED (20 W) at room
temperature (Scheme 1). We initiated our studies by selecting the
photochemical oxidation of N,N-dimethyl aniline in order to
optimize the reaction conditions (Table 1). To our delight, we
could isolate the desired αꢀaminonitrile in very high yield (96%)
2
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 3 of 6
Journal of Materials Chemistry A
View Article Online
DOI: 10.1039/C3TA14783E
in 4h using only 1 mol% of the TiO2ꢀgrafted ruthenium
photocatalyst 2 (Table 1, entry 2). In a controlled blank
experiment, there was no reaction occurred in the absence of
phenylpyrrolidine and Nꢀphenyltetrahydroꢀisoquinoline yielded
corresponding αꢀaminonitrile in high yields (Table 2, entries 7ꢀ
9). Under the described experimental conditions, aliphatic
photocatalyst (Table 1, entry 1). Similarly, there was no reaction 50 tertiary amine such as tertꢀbutyl amine did not produce any
5
observed by using nanocrystalline TiO2 as a catalyst (Table 1,
entry 3), proving that the rutheniumꢀpolyazine was truly required
for this transformation. When the reaction was performed by
using homogeneous ruthenium(II) polyazine complex as catalyst
(1 mol%) under described experimental conditions. The reaction
product (Table 2, entry 10). However, the reaction of tertiary
amines containing benzyl group was found to be slow and
provided corresponding amino nitriles in moderate yields (Table
2, entries 11ꢀ12).
55 Table 2: TiO2ꢀimmobilized ruthenium polyazine complex 2ꢀcatalyzed
oxidative cyanation of tertiary aminesa
10 did occur but afforded poor yield of the desired product,
indicating the promoting effect of TiO2 on the photocatalytic
activity of the catalyst (Table 1, entry 4). However, the reaction
of N,Nꢀdimethyl aniline with TiO2 immobilized photocatalyst 2
in the dark was found to be very slow and afforded poor yield of
15 the desired product (Table 1, entry 5). Furthermore, the use of air
in place of molecular oxygen afforded desired product in
comparatively lower yield (Table 1, entry 6). Acetic acid was
found to be crucial in this transformation and no reaction was
taken place in its absence (Table 1, entry 7). The role of acetic
20 acid can be attributed to the liberation of HCN in the presence of
Entry
1
Reactant
Product
Time Yield TOF
(h)
1
3
(%)b
(hꢀ1)
CH3
CH3
N
4
96
24
N
CH2CN
CH3
CH3
N
CH2CN
CH3
2
3
Me
4
91
23
Me
N
CH3
CH3
CH3
CH3
N
N
N
N
3.5
5
84
75
24
15
CH2CN
AcOH. Hence, acetic acid acts as
a coꢀcatalyst in this
CH3
CH3
CH3
transformation. To evaluate the effect of solvent, photochemical
oxidative cyanation of N,Nꢀdimethylaniline was studied in
various solvents such as dichloroethane, acetonitrile, toluene,
25 methanol and ethanol. The results of these experiments are
summarized in Table 1 (entries 8ꢀ11). Among the various
solvents studied polar and protic solvents such as methanol and
ethanol were found to be best reaction media for this
transformation.
4
CH2CN
Br
Br
CH3
CH3
N
Br
N
Br
4
4
85
90
88
21.2
22.5
19.5
5
6
7
CH2CN
CH3
CH3
CN
N
H
N
H
N
N
4.5
NC
30 Table 1: Results of the optimization experimentsa
N
8
9
N
4.5
5
89
92
20
N
+
NaCN/AOc
H
NC
Photocat. (1 mol%)
N
O
, so lvent
CN
2
1
N
18.4
N
Ph
Ph
Entry
Catalyst
(1 mol %)
ꢀ
2
TiO2
Solvent
Yield TOF
CN
(%)b
ꢀ
(hꢀ1)
ꢀ
48
30
24
ꢀ
ꢀ
ꢀ
(n-Bu)3N
10
11
1
2
3
MeOH
MeOH
MeOH
CH3
96
ꢀ
24
ꢀ
CH2CN
48d
55
1.6
2.3
N
CH3
N
CH3
4
5
6
7
8
9
10
11
Ru(II)polyazine MeOH
90
40c
92d
20e
22.5
10
23
5
CH3
CH3
CH2CN
N
N CH3
2
2
2
2
2
2
2
MeOH
MeOH
MeOH
12
aReaction conditions: Substrate 1 (1 mmol), catalyst 2 (1 mol %),NaCN (1.2
mmol), AcOH (1 ml), MeOH (4 mL) in the presence of O2 at room
temperature. bisolated yield
ClCH2CH2Cl trace
ꢀ
Toluene
CH3CN
EtOH
25
40
92
6.3
10
23
60 Further, we tested the recycling of the photocatalyst by selecting
the photochemical oxidation of the N,Nꢀdimethylaniline as
representative example. After completion of the reaction, the
photocatalyst was easily separated by filtration, washed with
acetone, dried and reused for subsequent experiments (for eight
65 runs). The results of the recycling experiments are depicted in
Fig. 3. In all cases, the yield of the desired product was found to
be almost similar, establishing the efficient recycling of the
catalyst. Furthermore, the selected filtrate samples were
subjected to ICPꢀAES analysis to check the leaching of the
70 metal/ ligand. No metal/ligand was observed during this course,
proving that the reaction was truly heterogeneous in nature and
no leaching had occurred during the photochemical reaction.
aReaction conditions: substarte (1 mmol), photocatalyst (1 mol%), NaCN (1.2
mmol), solvent (4 ml) in the presence of molecular oxygen; reaction time 4h;
bIsolated yield; cReaction was performed in dark; dby using air in place of
35 oxygen; eIn the absence of acetic acid.
To further investigate the substrate scope, the oxidative
cyanation of a variety of aromatic and cyclic tertiary amines was
studied under similar experimental conditions. The results of
these experiments are presented in Table 2. The conversion and
40 selectivity of the product was confirmed by GCMS and identity
was confirmed by comparing the physical and spectral data with
those of authentic samples. Among the various substrates,
aromatic substrates having electron donating groups (Table 2,
entries 2ꢀ3) were found to be more reactive as compared to the
45 substrates bearing electron withdrawing groups (Table 2, entries
4ꢀ5). Cyclic amines such as Nꢀphenyl piperidine, Nꢀ
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 3

Journal of Materials Chemistry A
Page 4 of 6
View Article Online
DOI: 10.1039/C3TA14783E
(*[Ru(bpy)2]2+ to generate intermediate [Ru(bpy)2]+ and a radical
25 cation of tertiary amine. The formation of transient species
[Ru(bpy)2]+ under visible light in the presence of a donor is well
documented in the literature. The photoredox catalyst was
regenerated by its reoxidation with molecular oxygen to give
superoxide radical anion (O2._). The second step of the reaction
30 probably involves the abstraction of hydrogen atom (H•) from the
amine cation radical B by the superoxide anion (O2ꢀ) to give
iminium ion intermediate C as shown in Scheme 3. The iminium
ion intermediate C subsequently reacts with hydrogen cyanide
that is insitu generated from NaCN and acetic acid to yield
35 corresponding αꢀamino nitrile.
Fig. 3: Results of recycling experiments
A comparison of the catalytic performance of the developed
photocatalyst with the previously reported heterogeneous
catalysts is shown in Table 3. In comparison to the previously
known catalysts (Table 3), the present photocatalyst has the
following significant advantages; a) the use of visible light, b)
the use of molecular oxygen as a terminal oxidant, c) the use of
lower catalyst concentration (1 mol%), d) higher product yields,
5
R1R2N-CH2R
RuII*
RuII
R1R2N-CHR
CN
R1R2N-CH2R
NaCN +AcOH
HCN
10 e) mild experimental conditions, f) the reusability of the TiO2
grafted ruthenium photocatalyst.
RuI
A
1,2-H shift
O2
-H+
+
+
_
R1R2N=CHR
O2
R1R2N-CH2R
O2
C
-OOH
B
Table 3: Comparison of various heterogeneous catalysts for oxidative
cyanation of tertiary amines
Scheme 3: Possible mechanism of the photocatalytic oxidative cyanation
In summary, we have developed for the first time an efficient,
recyclable and heterogeneous aerobic photocatalytic oxidative
40 cyanation of the tertiary amines to valuable compounds αꢀ
aminonitriles in high yields with molecular oxygen in presence
of NaCN in acetic acid under visible irradiation, using a
household white LED (20 W). It is anticipated that the developed
visible light photoredox catalyst can be further explored to
45 develop a number of environmentally benign and cost effective
methodologies for organic transformations.
CN source/
oxidant
Ethyl cyanoꢀ
Formate/ TBHP
Time/
h
Yield
(%)
Substrate
Catalyst
Ref
11
CH3
N
CH3
Ru/C (2
mol%)
Fe0.64H0.36PM
o12O40/
6.0
95
CH3
N
CH3
Ethyl cyanoꢀ
formate/ TBHP
7.0
96
12
7j
Nb2O5 (50
mg)
RuCl4ꢀ on
Starch (2
mol%)
CH3
N
CH3
NaCN/H2O2
NaCN/H2O2
NaCN/(tBuO)2
NaCN/ O2
2.0
2.5
2.5
12
82
95
90
71
We are thankful to the Director, CSIR-IIP for his kind
permission to publish these results. PK and SV acknowledge the
CSIR, New Delhi, for their Research Fellowships.
Polymer
supported
Fe(II)Pc (2
mol%)
Iron@graphe
ne oxide (2
mol%)
CH3
N
CH3
7f
50 Notes and references
CH3
N
CH3
7k
13
a Chemical Sciences Division,CSIR-Indian Institute of Petroleum, Dehradun-
248005, India; Tel.: +91-135-2525788; Fax. +91-135-2660202; Email:
suman@iip.res.in
Iron
CH3
N
CH3
oligopyridine
/ SBAꢀ15 (5
mol %)
TiO2 (1 eq.)
(11 W
General experimental procedure: A 25 mL round bottomed flask
55
60
65
equipped with a magnetic stirrer bar was charged with tertiary amine (1
mmol), NaCN (1.2 mmol), MeOH (2 mL), catalyst (1 mol %) and
AcOH (1 mL). The stirring was continued at room temperature under
oxygen atmosphere under visible irradiation, using a household white
LED (20 W). The progress of the reaction was monitored by TLC (SiO2).
After completion of the reaction, the catalyst was recovered by
precipitation with diethyl ether followed by filtration. The obtained
organic layer was washed with water, dried over anhydrous Na2SO4 and
concentrated under vacuum to give crude product, which was purified by
flash chromatography to afford pure αꢀaminonitrile. The conversion of
tertiary amines into corresponding αꢀaminonitriles and their selectivity
was determined by GCꢀMS (EI quadrupol mass analyzer, EM detector)
and the identity of the selected products was established by comparing
their spectral data with authentic samples.
KCN/ O2
20
2
95
90
14
15
N
fluorescent)
Ph
CH3
N
CH3
MnO2ꢀbased
catalyst (2g)
TiO2
supported
ruthenium
(II)polyazine
( 1mol%)
TMSCN/ O2
CH3
N
CH3
NaCN/ O2
4.0
96
ꢀ
15
Although the exact mechanism of the reaction is not known at
this stage, the possible mechanistic pathway of the reaction is
shown in Scheme 3. In analogy to the existing reports, two
20 important steps can be assumed for the photocatalytic oxidative
cyanation of the tertiary amine. The first step of the reaction may
1. a) K. Zeitler, Angew. Chem., Int. Ed., 2009, 48, 9785–9789; b) P.
Melchiorre, Angew. Chem., Int. Ed., 2009, 48, 1360–1363.; c) T. P.
Yoon, M. A. Ischay, J. N. Du, Nat. Chem., 2010, 2, 527–532.; d) J. M. R.
Narayanam, C. R. J. Stephenson, Chem. Soc. Rev., 2011, 40, 102–113.
2. a) L. Giribabu, V. K. Singh, C. V. Kumar, Y. Soujanya, V. G. Reddy, P.
Reddy Adv Opto Elect. 2011, 2011, 8.
70
involve the single electron transfer from tertiary amine for 75 3. a) Z. Yan, S. Chinta, A. A. Mohamed, J. P. Fackler Jr., D. Wayne
Goodman Catal. Lett. 2006, 111, 1–2.; b) Y. Li , J. Chen , J .Liu , M. Ma
, C.W, L.L. J Environ Sci 2010, 22, 1290ꢀ1296.
reductive quenching of the excited triplet state of the complex
4
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 5 of 6
Journal of Materials Chemistry A
View Article Online
DOI: 10.1039/C3TA14783E
4. a) D. Enders, J. Kirchhoff, P. Gerdes, D. Mannes, G. Raabe, J. Runsink,
G. Boche, M. Marsch, H. Ahlbrecht, H. Sommer, Eur. J. Org. Chem.
1998, 63ꢀ71. b) E. J. Martinez, E. J. Corey, Org. Lett. 1999, 1, 75ꢀ78.
5. a) M. North, Comprehensive Organic Functional Group
Transformations, Vol. 3 (Eds.: A. R. Katritzky, O. MethꢀCohn, C. W.
Rees, G. Pattenden), Pergamon, Oxford, 1995, 611–617; b) K. Surendra,
N. S. Krishnaveni, A. Mahesh, K. R. Rao, J. Org. Chem. 2006, 71, 2532ꢀ
2534.; c) Y. Fukuda, K. Kondo T. Aoyama, Synthesis 2006, 2649ꢀ2652.;
d) B. Das, K. Damodar, B. Shashikanth, Y. Srinivas, I. Kalavathi, Synlett
2008, 20, 3133ꢀ3134.; e) A. Majhi, S. S. Kim, H. S. Kim, Appl.
Organomet. Chem. 2008, 22, 466ꢀ470; f) C. Wiles, P. Watts, Eur. J. Org.
Chem. 2008, 5597ꢀ5613.
6. a) S. I. Murahashi, D. Zhang, Chem. Soc. Rev., 2008, 37, 1490–1501.; b)
C. J. Li, Acc. Chem. Res., 2009, 42, 335–344.; c) Z. Li, D. S. Bohle, C.ꢀ
J. Li, Proc. Natl. Acad. Sci. U. S. A., 2006, 103, 8928–8933.; d) W.ꢀJ.
Yoo, C.ꢀJ. Li, Top. Curr. Chem., 2010, 292, 281–302.; e) C. S. Yeung,
V. M. Dong, Chem. Rev., 2011, 111, 1215–1292.; f) C.ꢀL. Sun, B.ꢀJ. Li,
Z.ꢀJ. Shi, Chem. Rev., 2011, 111, 1293–1314.; g) C. Liu, H. Zhang, W.
Shi, A. Lei, Chem. Rev., 2011, 111, 1780–1824.; h) S. Verma, S. L. Jain
and B. Sain, Catal. Lett., 2011, 141, 882–885.; i) Y. Zhang, H. Peng, M.
Zhang, Y. Cheng, C. Zhu, Chem. Commun., 2011, 47, 2354–2356.; (j) P.
Liu, Y. Liu, L.ꢀM. Wong, S. Xiang, C.ꢀM. Che, Chem. Sci., 2011, 2,
2187–2195.; k) J. M. Allen, T. Lambert, J. Am. Chem. Soc., 2011, 133,
1260–1262.; l) X.ꢀZ. Shu, X.ꢀF. Xia, Y.ꢀF. Yang, K.ꢀG. Ji, X.ꢀY. Liu, Y.ꢀ
M. Liang, J. Org. Chem., 2009, 74, 7464–7469; m) T. Tajima, A.
Nakajima, J. Am. Chem. Soc., 2008, 130, 10496–10497.; n) S. S.
Libendi, Y. Demizu, O. Onomura, Org. Biomol. Chem., 2009, 7, 351–
356.; o) F. Louafi, J.ꢀP. Hurvois, A. Chibani, T. Roisnel, J. Org. Chem.,
2010, 75, 5721–5724.
5
10
15
20
25
30 7. a) C.ꢀK. Chen, A. G. Hortmann, M. R. Marzabadi, J. Am. Chem. Soc.
1988, 110, 4829ꢀ4831.; b) S.ꢀI. Murahashi, T. Nakae, H. Terai, N.
Komiya, J. Am. Chem. Soc. 2008, 130, 11005ꢀ11012.; c) M. North,
Angew. Chem. 2004, 116, 4218ꢀ4220.; d) S.ꢀI. Murahashi, N. Komiya, H.
Terai, T. Nakae, J. Am. Chem. Soc. 2003, 125, 15312ꢀ15313.; e) S.ꢀI.
35
40
45
50
Murahashi, T. Naota, N. Miyaguchi, T. Nakato, Tetrahedron Lett. 1992,
33, 6991ꢀ6994.; f) S. Singhal, S. L. Jain, B. Sain, Adv. Synth. Catal.
2010, 352, 1338ꢀ1344.; g) W. Han, A. R. Ofial, Chem. Commun. 2009,
5024ꢀ5025.; h) S. Singhal, S. L. Jain, B. Sain, Chem. Commun. 2009,
2371ꢀ2372.; i) S.ꢀI. Murahashi, N. Komiya, H. Terai, Angew. Chem.
2005, 117, 7091ꢀ7093.; Angew. Chem. Int. Ed. 2005, 44, 6931.; j) S.
Verma, S. L. Jain, B. Sain, ChemCatChem 2011, 3, 1329ꢀ1332.; k) D.
Verma, S. Verma, A. K. Sinha, S. L. Jain, ChemPlusChem 2013, 78,
860ꢀ865.
8. M. Rueping, S. Zhu, R. M. Koenigs, Chem. Commun., 2011, 47, 12709ꢀ
12711.
9. C. H. Lee, S. W. Rhee , H. W.Choi, Nanoscale Res. Lett. 2012, 7, 48ꢀ52.
10. N. G. Joby, P. Venkatachalam, N. Krishnakumar, Int. J. Sci. Eng. Res.
2013, 4, 1317ꢀ1327.
11. K. Harha, V. Reddy, G. Satish,V. P. Reddy, B. S. P. A. Kumar, Y. V. D.
Nageswar, RSC Adv. 2012, 2, 11084ꢀ11088.
12. K. Tirumala, V. Rao, B. Haribabu, P. S. S. Prasad, N. Lingaiah,
ChemCatChem 2012, 4, 1173ꢀ1178.
13. P. Liu, Y. Liu, E. L.ꢀM. Wong, S. Xiang, C.ꢀM. Che, Chem. Sci. 2011, 2,
2187ꢀ2195.
55 14. M. Rueping, J. Zoller, D. C. Fabry, K. Poscharny, R. M. Koenigs, T. E.
Weirich, J. Mayer, Chem. Eur. J. 2012, 18, 3478ꢀ3481.
15. K. Yamaguchi, Y. Wang, N. Mizuno, ChemCatChem 2013, 5, 2835ꢀ
2838.
60
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 5

Journal of Materials Chemistry A
Page 6 of 6
View Article Online
DOI: 10.1039/C3TA14783E
TiO2 immobilized Ru(II) polyazine complex: a visibleꢀlight
active photoredox catalyst for oxidative cyanation of tertiary
amines
Pawan Kumar, Sanny Varma and Suman Jain
5
6
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]