Amido-pincer complexes of Cu(II): Synthesis, coordination chemistry and applications in catalysis

Article abstract of DOI:10.1016/j.jorganchem.2017.03.021

The synthesis and characterisation of five novel copper (II) complexes incorporating an amido pincer ligand derived from the deprotonation of N-(2-{4,4-dimethyl-4,5-Dihydrooxazol-2-yl}phenyl)picolinamide (i.e., L1H) or a chiral indanol-based congener (L2H) are described. These Cu materials are obtained from the treatment of EtOH solutions of L1H or L2H with CuX₂(OH₂)_n species (X = Cl, Br, NO₃, BF₄). All of these compounds have been characterised by single crystal X-ray diffraction methods, which confirms a k³-N,N′,N″-binding mode of the formally anionic L1 or L2 displaying an amido N-Cu bond following H⁺ loss. Complexes of stoichiometry Cu(L1)X (X = Cl [1], Br [2]) are shown to be slightly distorted square planar compounds with an N₃X ligand binding set. For X = BF₄, the Cu compound retains a coordinated H₂O molecule and a non-coordinated BF₄ counteranion to form [Cu(L1)(OH₂)]BF₄·H₂O (3). This species demonstrates extended solid-state structure which is likewise detailed. In the case of X = NO₃, the isolated species (4) is six-coordinate in nature with a κ²-O,O′-NO₃ ligand and a non-coordinated solvent of crystallisation (H₂O). This latter species displays a bridged dimeric structure in the solid-state and can alternatively be produced, albeit in reduced yields, from 1 and AgNO₃ in wet THF mixtures. A chiral derivative, Cu(L2)Cl (i.e., 5), has also be produced by similar synthetic protocols and structurally elucidated; it displays a solid-state structure somewhat different to that of 1. The catalytic activity of both 1 and 3 was investigated towards C-C bond forming chemistry, notably the Henry (i.e., nitroaldol) reaction and methyl methacrylate polymerisation. Electrochemical investigations of these complexes display irreversible one-electron reduction potentials; a facet which helps to explain their negligible catalytic activity in (presumed) ATRP. However, both 1 and 3 are marginally active in promoting the nitroaldol reaction but the product profile is hampered by both low conversions and the formation of by-product alkenes. In contrast, 1–4 are very effective catalytic promoters of the heteroannulation reaction of 2-iodophenol and phenylacetylene to yield the corresponding 2-phenylbenzofuran in the presence of base.

Full text of DOI:10.1016/j.jorganchem.2017.03.021

Accepted Manuscript
Amido-pincer complexes of Cu(II): Synthesis, coordination chemistry and applications
in catalysis
Mahroo Taghvaee, María J. Rodríguez-Álvarez, Joaquín García-Álvarez, Ignacio del
Río, Alan J. Lough, Robert A. Gossage
PII:
S0022-328X(17)30169-9
10.1016/j.jorganchem.2017.03.021
JOM 19855
DOI:
Reference:
To appear in: Journal of Organometallic Chemistry
Received Date: 20 November 2016
Revised Date: 6 March 2017
Accepted Date: 9 March 2017
Please cite this article as: M. Taghvaee, M.J. Rodríguez-Álvarez, J. García-Álvarez, I. del
Río, A.J. Lough, R.A. Gossage, Amido-pincer complexes of Cu(II): Synthesis, coordination
chemistry and applications in catalysis, Journal of Organometallic Chemistry (2017), doi: 10.1016/
j.jorganchem.2017.03.021.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT
Graphical Abstract:

ACCEPTED MANUSCRIPT
Amido-Pincer Complexes of Cu(II): Synthesis, Coordination Chemistry and
Applicaꢀons in Catalysis†
a
b
b
c
d
Mahroo Taghvaee, María J. Rodríguez-Álvarez, Joaquín García-Álvarez, Ignacio del Río, Alan J. Lough
a*
and Robert A. Gossage
a
Department of Chemistry & Biology, Ryerson University, 350 Victoria Street, Toronto ON Canada M5B 2K3. E-mail:
gossage@ryerson.ca fax: +1-4169795044
b
Laboratorio de Compuestos Organometálicos y Catálisis (Unidad Asociada al CSIC), Centro de Innovación en Química
Avanzada (ORFEO-CINQA), Departamento de Química Orgánica e Inorgánica (IUQOEM), Facultad de Química, Universidad de
Oviedo, 33071 Oviedo, Spain
c
Departamento de Química Orgánica e Inorgánica, Facultad de Química, Universidad de Oviedo, 33071 Oviedo, Spain
d
Department of Chemistry, University of Toronto, 80 St. George Street, Toronto ON M5S 3H6 Canada. Correspondence author
for crystallographic work; e-mail: alough@chem.utronto.ca
This manuscript is dedicated to Prof. Dr. Gerard van Koten in recognition of his outstanding contributions to
th
organometallic chemistry and on the occasion of his 75 birthday. Happy birthday Gerard !
† Electronic Supplementary Information (ESI) available: checkcif files for CCDC #1491490-1491494, selected observed
and calculated structural data, NMR data, mol2 file. See DOI:xxxx

2
ACCEPTED MANUSCRIPT
Abstract. The synthesis and characterisation of five novel copper (II) complexes incorporating an amido pincer ligand derived
from the deprotonation of N-(2-{4,4-dimethyl-4,5-Dihydrooxazol-2-yl}phenyl)picolinamide (i.e., L1H) or a chiral indanol-based
congener (L2H) are described. These Cu materials are obtained from the treatment of EtOH solutions of L1H or L2H with
CuX (OH ) species (X = Cl, Br, NO , BF ). All of these compounds have been characterised by single crystal X-ray diffraction
2
2 n
3
4
3
methods, which confirms a κ -N,N’,N”-binding mode of the formally anionic L1 or L2 displaying an amido N-Cu bond
+
following H loss. Complexes of stoichiometry Cu(L1)X (X = Cl [1], Br [2]) are shown to be slightly distorted square planar
compounds with an N X ligand binding set. For X = BF , the Cu compound retains a coordinated H O molecule and a non-
3
4
2
coordinated BF counteranion to form [Cu(L1)(OH )]BF •H O (3). This species demonstrates extended solid-state structure
4
2
4
2
2
which is likewise detailed. In the case of X = NO , the isolated species (4) is six-coordinate in nature with a κ -O,O’-NO ligand
3
3
and a non-coordinated solvent of crystallisation (H O). This latter species displays a bridged dimeric structure in the solid-
2
state and can alternatively be produced, albeit in reduced yields, from 1 and AgNO in wet THF mixtures. A chiral derivative,
3
Cu(L2)Cl (i.e., 5), has also be produced by similar synthetic protocols and structurally elucidated; it displays a solid-state
structure somewhat different to that of 1. The catalytic activity of both 1 and 3 was investigated towards C-C bond forming
chemistry, notably the Henry (i.e., nitroaldol) reaction and methyl methacrylate polymerisation. Electrochemical
investigations of these complexes display irreversible one-electron reduction potentials; a facet which helps to explain their
negligible catalytic activity in (presumed) ATRP. However, both 1 and 3 are marginally active in promoting the nitroaldol
reaction but the product profile is hampered by both low conversions and the formation of by-product alkenes. In contrast, 1
-
4 are very effective catalytic promoters of the heteroannulation reaction of 2-iodophenol and phenylacetylene to yield the
corresponding 2-phenylbenzofuran in the presence of base.
Keywords: pincer, copper, amido, oxazoline, heteroannulation catalyst

3
ACCEPTED MANUSCRIPT
The synthesis of amides L1H and L2H was carried out as
previously reported [11]. Complexes (Scheme 2) were
1
. Introduction
1-4
3
Pincer ligands are typically classified as
κ -binding agents in
synthesised by a simple treatment of L1H with the appropriate
cupric halide or pseudo-halide salt (i.e., CuCl •2H O, anhyd.
which one formally anionic centre, which can be either a C
atom or other element, is linked to two other, typically
neutral, electron donating groups [1-3]. These latter
functionalities usually involve nucleophilic P, N, O, S and/or Se
atoms or the presence of secondary C-centres such as
carbene-based donor sites [4]. Since the first pincer complexes
were reported in the 1970s, this class of materials has greatly
expanded and now the ligand framework is often referred to
as one of the “privileged” classes of metal binding agents [1-5].
This designation is largely due to the atypical properties
associated with pincer complexes which includes aspects such
as unusually high thermal stabilities [1-3], potent and selective
catalytic activity [1-6], the ability to stabilise rare oxidation
2
2
CuBr , Cu(BF ) •6H O, or Cu(NO ) •2.5H O) in a 1:1 molar ratio
3 2
2
4 2
2
2
with the reagents dissolved in 95 % EtOH under ambient
conditions (Scheme 2). Following overnight stirring and
filtration, all volatile components of the mixtures were
removed (vacuo). The resulting compounds were subsequently
washed with excess Et O and dried in air. This procedure
2
yielded the crude green-coloured air-stable products in
excellent yields (
1
: 85%;
2
: 89%;
3
: 95%;
4: 90%). The nitrate
complex 4 can also be obtained from complex
1
via treatment
of this material with AgNO in a wet THF mixture, followed by
3
filtration and isolation as above; albeit in slightly lower yield
(76%).
2+
3+
3+
states (e.g., Rh , Ni , Cu ) [1-5] and unusual photochemical
behaviour [7].
An important sub-class of the pincers are those containing
a formal N,N’N- or an N,N’,N”-donor atom set in which the
central N-atom is a formally anionic donor centre. These
materials are classified as amido-pincers [8-11]. We, and
others, have been investigating such ligands [10-13] and in
particular those that incorporate an oxazoline (ox) group [14]
as a flanking N-donor site(s). Some examples of these are
Scheme 2. Synthesis of Complexes 1-4.
In a similar way, green-coloured (chiral) complex
5 was
produced from L2H (Scheme 2) via treatment of this material
with hydrated cupric chloride (Scheme 3; yield: 82%).
shown in Scheme 1.
Scheme 1. Some examples of oxazoline containing amido-pincer precursors.
This study involves a coordination chemical study involving
2+
the use of L1H and L2H (Scheme 1) with Cu metal centres.
Related cupric pincer complexes have shown noteworthy
structural aspects in addition to catalytic potency in a number of
organic transformations [15]. Herein, we report the synthesis
and full characterisation of five new formally Cu(II) complexes
incorporating the formal anions derived from L1H and L2H (i.e.
Scheme 3. The synthesis of complex 5.
2
.2. Structural Characterisation and Structural Trends
Single crystal X-ray diffraction studies were carried out on
compounds to investigate further their precise structural
reactions such as the nitroaldol reaction, methyl methacrylate nature and properties. Complex and its bromide congener
MMA] polymerisation and the heteroannulation of 2- are shown to be mononuclear species with very similar
−
−
L1 and L2 ). We also describe our preliminary investigations
into the application of these materials in C C bond forming
1-5
−
1
2
[
iodophenol with phenylacetylene.
structural features (Scheme 4). The coordination environment
around the metal centre is comprised of a single metal-bound
halido which occupies a pseudo-trans position (vide infra) to
the N-atom of the assumed deprotonated amide grouping.
This formal amido-Cu interaction [16] is supplemented by
2
. Results and discussion
2
.1. Synthesis of Complexes 1-5

4
ACCEPTED MANUSCRIPT
coordination of both pyridine and oxazoline groups, via their coordinate N O ligand binding set. In terms of a more
3
2
N-atoms [10, 11, 13, 17], forming five- and six-membered accurate geometric descriptor, the calculated τ value of 0.392
5
3
rings, respectfully and hence displaying a
κ -N,N’N” bonding reveals what is best described as highly distorted square
mode. Both materials contain two unique molecules of the pyramidal arrangement around Cu [22].
complex found within the unit cell.† However, the general
structural features are not significantly variable and hence the
coordination geometry around the Cu atom in all cases is best
described as quite distorted square planar in nature with
calculated τ4 values of 0.348 and 0.389 for
.380 and 0.398 ( : av. = 0.389) [18].
1 (av. = 0.369) and
0
2
Figure 1. An ORTEP view of the cation / anion pair of complex 3 found within the unit
cell with the associated unit cell contents.
Complex
features. As with
displaced by L1 and a unsymmetrical
unit (dCu-O = 2.016(2); 2.528(3)Å) is also found [23].
Reminiscent of , further intermolecular interactions (dC=O•••Cu
1 and 2, bond lengths between the ligated Cu atom = 2.827(3)Å) are also noted between a neighbouring amide
4
likewise displays some unique structural
1
and , all water molecules have been
2
2
κ
-O,O’ bonded nitrate
Scheme 4. ORTEP representations of one of the molecules in the unit cell of complex 1
19
(
left) and 2 (right). Hydrogen atoms have been omiꢀed for clarity.†
3
In both
and the N X donor atom set are otherwise unsurprising† and C=O and Cu effectively forming an octahedral geometry
3
can be compared to similar formally Cu(II)-E (E = N or halido) around the metal centre. In this case however, this leads to
bond distances in related materials [20]. The organic the formation of a dimeric [Cu(L1)(NO )] species in the solid-
3
2
framework is predictably slightly distorted from planarity and state (Figure 2).
can be compared to the corresponding square planar materials
incorporating a Group 10 metal centre [10, 11, 13]. The two
structural forms of complex
1 found within the unit cell have
some differences as noted; specifically within the vicinity of
the metal centre. To explore this aspect from a different
perspective, complex
PM6(tm)/DFT [17d, 21] treatment of a hypothetical gas phase
species.† Preliminary geometric opꢁmizaꢁon of was carried
1 was subject to analysis via a combined
1
out using a semi-empirical PM6(tm) treatment and this
structure was then applied for more detailed analysis using
DFT at the 6-31G*/LANL2DZ level of theory. This relatively
basic level of theoretical calculation was found to be adequate
Figure 2. ORTEP representation of a dimeric solid-state unit of 4 found within the unit
cell.
As our interests lie in the broad areas of ligand design,
structural studies and catalysis, we produced a chiral analogue
in mimicking an ‘average’ of the two structural forms of
1
found in the solid. This suggests that the variation in the solid
phase may simply be due to optimised packing effects. Further
details on these aspects can be found in the ESI.†
of
structural aspects of
relative. Interestingly, complex
1
, i.e.,
5
. This was undertaken to investigate whether the
are readily translated to a chiral
appears to have a number of
hybrid” structural aspects as shown by the trio of and
crystallises on the P212121 space group and
1
5
The solid-state structure of compound
3
features aspects
or . In this case,
“
1
,
3
4.
not found in either of the halido materials
–
the pseudo-halide counteranion (i.e., BF ) is not metal-bound
4
1
2
Compound 5
displays what can be described as an almost square planar
3
arrangement of the κ -N,N’N”-bound L1 and chlorido ligand
and instead a molecule of coordinated water remains attached
1
to the Cu centre in the typical
κ
–O bonding motif (Figure 1). In
(Figure 3:
∠ Namido-Cu-Cl = 172.25(6)°; ∠ N -Cu-N = 171.26
py ox
addition, secondary bonding interactions between the amido
O-atom of a neighbouring Cu complex is noted within the unit
cell. The intermolecular C=O•••Cu distance is certainly longer
(9)°). As observed with complexes
3
and
4
, additional
intermolecular interactions between the Cu centre and an
adjacent amido-derived carbonyl group is noted with a
C=O•••Cu distance of 2.5060(18)Å. This results in a geometry
around copper that is very close to idealised square pyramidal
than typical Cu-O bond lengths (2.298(2)Å; cf. Cu-OH bond
2
length in
3: 1.971(3)Å) but within the sum of the van der Waals
radii. Hence, this interaction serves to complete a formal five-
in nature (τ = 0.017) [18], unlike 1-4 (Figure 3). In further
5

5
ACCEPTED MANUSCRIPT
contrast to these latter materials,
5
also forms chains heteroannulation catalysts for the formation of 2-
consisting of units of
5 facilitated by µ-links through the amido phenylbenzofuran (9: Equation 1) from o-iodophenol (IP) and
C=O group (ESI†‡).
phenylacetylene (PA) was thereafter realised. This latter
investigation was inspired by the recent work by Moure et al.
[
28a] who have disclosed that pincer-type complexes of Cu(II)
are effective promoters of such ring formation.
Equation 1.
We therefore investigated the use of
1 and 3 in this regard
using similar conditions as those noted previously [28]. These
results are summarised in Table 1 (vide infra).
Figure 3. An ORTEP view of a molecule of 5 found within the solid-state unit cell.
Table 1.
a
Entry
2
.3. Electrochemistry and Catalysis
Catalyst
mol %)
Equiv.
Temp.
(°C)
Time
(h)
Yield
b
(%)
(
of PA
Complexes 1-5 were further investigated for their
9/10/11
electrochemical behaviour using Cyclic Voltammetry (CV) [23].
1
2
3
4
5
6
7
8
9
1
3
1
3
1
3
1
3
(5)
(5)
(5)
(5)
(1)
(1)
(5)
(5)
1.2
1.2
1
130
130
130
130
130
130
80
48
48
7
60/21/9
73/15/5
86/8/0
83/9/4
82/6/4
90/4/2
13/1/0
25/1/0
0/0/0
In dichloromethane solution containing n-Bu NClO as
4
4
supporting electrolyte, complexes
1-5 showed only reduction
responses at E = -0.34, -0.21, -0.39, -0.30, -0.31V, respectively,
a
II
I
which can be attributed to irreversible Cu /Cu process [24].
There were also in some cases irreversible oxidation at higher
potentials which is presumably due to ligand based oxidation.
As reversible oxidation-reduction at Cu is known as a pre-
requisite for activity in Atom Transfer Radical Polymerisation
1
7
1
24
24
24
24
7
1
1
1
80
(ATRP) [25], it is hardly surprising that none of these
none
1
130
130
130
complexes demonstrated any reactivity when tested in ATRP
using methyl methacrylate as reactive monomer.§ Thus, we
felt that screening these materials in a benchmark Cu-
catalysed process, namely the nitroaldol (Henry [26]) reaction,
might lead to better activities. A vast array of Cu complexes
have been found to be suitable catalysts for the Henry reaction
1
1
0
1
2
4
(1)
(1)
1
24
24
87/6/2
83/7/2
1
a
General conditions: Ar atmosphere; 0.5 mmol of IP in 2 mL
b
,4-dioxane; yields determined by GC.
1
The best results in terms of conversion of reactants to give 2-
phenylbenzofuran ( ) is detailed as entry 6 where a 90% yield
of desired product was achieved using 1 mol% of . By-product
[
27] and this is an attractive C-C bond forming process as the
9
product β-nitroalcohols are important intermediates in
chemical synthesis. Thus, the pincer complexes were tested as
3
formation (Glaser coupling [29a] to give 10 or hydration of PA
to give 11) under these conditions is likewise minimised [28,
promoters for the addition of nitromethane
benzaldehyde ( ) to yield 2-nitro-1-phenylethanol (
activity was noted (RT; 24 h) using CHCl as reaction medium
(
6
)
to
7
8). No
2
9]. For completeness, we also studied the catalytic activity of
the rest of the neutral achiral complexes ( and ) under the
optimized reaction conditions (entries 10 and 11). As expected,
the exchange of a chlorido ( ) by other formally anionic ligands
i.e., Br [ ] or NO3 [ ]) gave rise to similar catalytic results, both
3
2
4
using
1
(10 mol%),
6
(5 mmol) and
7
(1 mmol). The application
, but only to form
the by-product β-nitrostyrene as a result of the rapid
dehydration of [27]. Less than 5% conversion to was noted
of CH Cl or toluene did show conversion of
7
2
2
1
(
2
4
8
8
in terms of activity and selectivity. This suggests the possibility
of a common reactive intermediate in these cases. These
preliminary results will serve as a starting point for an
expanded investigation into this catalytic system involving
further optimisation studies and an elucidation of the
mechanism of action of these catalysts in such chemistry.
These results will be disclosed in due course.
using THF or 95% EtOH as solvent and this result was not
improved with the application of heat. This situation was
slightly improved by employing complex
presumably due to the potential lability of the Cu-bound water
molecule. Yields of as high as 25% could be achieved, but
modification of the reaction conditions (temp. variation,
additional , etc.) to attempt to increase this value were
entirely unsuccessful.§§ As a result, further attempts to
optimize these systems or investigate any potential enantio- 3. Conclusions
selectivity with complex was therefore abandoned. Despite
these setbacks, the application of both and as
3 as catalyst,
8
6
5
1
3

6
ACCEPTED MANUSCRIPT
Five novel amido-based pincer complexes, differing primarily subsequently stirred for 24 h (RT). The mixture was then
in the nature of a (pseudo-)halido or the amido-pincer ligand, filtered by gravity filtration through filter paper and the
have been synthesised and fully characterised. These materials collected green coloured powder was then washed with Et O
2
show somewhat surprising structural variation in the solid- (3 × 5 mL). This product, in the form of a powder, was then
state with extended solid-state structure being noted in three dried on a rotary evaporator and thereafter isolated (yield:
of the five complexes. DFT calculations at the B3LYP 6- 0.51 g [85%]). Crystalline material, in the form of green
3
1G*/LANL2DZ level of theory were found to be adequate in coloured crystals suitable for X-ray diffraction study, were
mirroring the general structural features of 1 experimentally obtained by dissolving the product (0.2 g) in CH Cl (2 mL) and
2
2
observed in the solid-state. One of these materials was tested then layering this mixture with Et O (5 mL); crystals were
2
for ATRP ability and found to be inactive, likely due to a poor isolated from the loosely-sealed vial after slow evaporation of
electrochemical profile. Two of the complexes (
found to be moderately active as catalysts for the nitro-aldol
Henry) reaction but the usefulness of these compounds is IR (cm ): 3074 (w), 2968 (m), 1618 (s), 1602 (s), 1488 (s), 1344
hampered by a combination of low product yields and side- (s), 750 (s), 687 (s), 531 (m).
reaction (alkene) product formation. In contrast, both or
1, 3) were solvents over a period of approximately one week.
-
1
(
1
3
-4
were found to be quite active catalysts for heteroannulation UV/Vis. (c = 1.0
× 10 g/mL: CH Cl ): λ = 342 nm (ε = 7792).
2 2 max
chemistry. Good to excellent product profiles are noted for the
conversion of
a
combination of 2-iodophenol and Elemental Analysis calc’d. for C H N O ClCu (%): C 51.91, H
17 16 3 2
phenylacetylene to yield the heterocycle 2-phenylbenzofuran.
4.10, N 10.68; found: C 51.73, H 4.09, N 10.53.
4
.2.2. Synthesis of Compound 2
4
. Experimental
Compound L1H (1.00 mmol, 0.340 g) was dissolved in 20 ml of
ethanol (95%) and transferred to a 100 mL round-bottomed
flask at room temperature. To this stirred mixture then was
4
.1. General
All reactions were carried out using standard bench-top
laboratory techniques using commercially available, reagent
grade solvents some of which (e.g., THF) were further purified
by a solvent purification system. Air-sensitive reactions were
carried out under an atmosphere of dinitrogen gas using
standard vacuum-line Schlenk techniques. Compounds L1H
added anhydrous CuBr (0.22 g, 1.00 mmol) and stirring was
2
continued for 24 h (RT). The dark green solution was then
filtered by gravity filtration (filter paper) and isolated solid
then washed with diethyl ether (3 × 5 mL). The isolated green
coloured product was then dried in vacuo (Yield: 89%, 0.39 g).
Green-coloured crystals suitable for X-ray diffraction were
grown by dissolving the 0.2 g of the crude powder in 2 mL of
CH Cl and then layering this mixture with Et O (5mL) and
1
0, 11 1
and L2H were synthesised as previously described.
H and
1
3
C NMR were recorded from chloroform-d solutions (400 and
00.6 MHz, respectively) using a Bruker Avance spectrometer.
1
2
2
2
covering the top of the vial. Green crystals formed after
approximately 48 h.
UV-Vis measurements were carried out using a Perkin Elmer
Lambda 20 spectrophotometer. IR spectra were obtained from
KBr disks on
a
Perkin Elmer Spectrum 60 IR
-
IR (cm ): 3074 (w), 2969 (m), 1633 (s), 1615 (s), 1488 (s), 1346
1
spectrophotometer. Melting point was determined using
Fisher Scientific melting point apparatus up to a maximum
temperature of 300 °C. CV measurements were carried out
using equipment and techniques previously disclosed [24]. The
X-ray crystal structure determinations were performed as
previously described† [13b, 30]. Elemental analysis data were
supplied by Atlantic Microanalytical of Norcoss GA (U.S.A.).
DFT calculaꢁons (ESI†) were performed as detailed previously
(s), 749 (s), 686 (s), 531 (m).
-
4
UV/Vis. (c = 1.0
× 10 g/mL: CH Cl ): λ = 348 nm (ε = 8022).
2 2 max
Elemental Analysis calc’d. for C H N O CuBr (%): C 46.64, H
17 16
3
2
3
.68, N 9.60; found: C 46.39, H 3.70, N 9.37.
4
.2.3. Synthesis of Compound 3
[
30b, 31] using the Spartan 10.0™ software package [32].
To a mixture of 20 mL ethanol (95%) and ligand L1H (0.300 g,
1.00 mmol) in a 100 mL round-bottomed flask at the room
temperature, was then added Cu(BF ) •6H O (1.00 mmol, 0.36
4
4
.2 Syntheses
.2.1. Synthesis of Compound 1
4 2
2
g). The reaction mixture then stirred (RT) for 12 h. The reaction
content was then filtered twice by a gravity filtration. The clear
green liquid was left under the fume hood to evaporate the
solvent. Green-coloured needle-shaped crystals were formed
in the solution by the slow evaporation of volatile
components. The isolated crystals were then washed with
diethyl ether (2 × 2 mL) and dried in open atmosphere (Yield:
In a 100 mL round-bottomed flask containing 20 mL of ethanol
EtOH: 95%), was added L1H (1.52 mmol, 0.450 g), directly as a
(
solid at room temperature (RT). The resulting solution was
stirred until complete dissolution of the solid material. A
sample of CuCl •2H O (0.26 g: 1.52 mmol) was then added to
2
2
this mixture. The colour of the mixture immediately turned
from a light yellow to a dark green. Reaction mixture was
0
.44 g; 95%).

7
ACCEPTED MANUSCRIPT
-
1
IR (KBr: cm ): 2926 (m), 1626 (s), 1487 (s), 1338 (m), 1216 (m),
IR (KBr cm ): 3348 (m), 3070 (m), 1612 (s), 1543 (s), 1486 (s), 1126 (m), 1076 (m), 1013 (m), 755 (s), 687 (s), 538 (m), 458
-1
1
382 (s), 1077 (s), 758 (s), 688 (s), 662 (w).
(w).
-
4
-4
UV/Vis. (c = 1
×
10 g/mL: CH Cl ): λ = 344 nm, (ε = 6772).
2
UV/Vis. (c = 1 × 10 g/mL: CH Cl ): λ = 349 nm (ε = 7656).
2 2 max
2
max
Elemental Analysis calc’d. for C H BF N O Cu•1.5H O (%): C Elemental Analysis calc’d. for C H O N ClCu (%): C 58.28, H
18
17
4
3
3
2
22 16 2 3
4
1.69, H 4.32, N 8.58; found: C 41.40, H 4.13, N 8.48.
3.56, N 9.27; found: C 58.04, H 3.71, N 9.06.
4
.2.4. Synthesis of Compound 4
4.3. Catalysis
Route (a): Compound L1H (0.50 mmol, 0.196 g) was dissolved 4.3.1. Nitroaldol catalysis
in 10 mL of THF in an open vessel and AgNO (0.50 mmol,
3
The investigations of complexes
Henry reaction was carried out as follows. A sample of
nitromethane (5 mmol), benzaldehyde (1 mmol) and catalyst
or (5 mol %) were placed in a round-bottomed flask with an
appropriate solvent (20 mL: see text). Stirring was initiated for
4 h and then the contents of the flask were isolated via
column chromatography.
1, 3 and 5 in promoting the
0
.085 g) was then added to this mixture; stirring was then
initiated and continued at RT for 4 h. A white precipitate
presumably AgCl) was removed from the mixture by gravity
1
(
3
filtration. The remaining green mixture was left overnight in an
open atmosphere allow for the evaporation of all volatile
components. The resulting green coloured powder that was
formed was thereafter isolated (Yield: 76%, 0.16 g). Green-
coloured crystals suitable for X-ray diffraction were grown
from a sealed vessel containing 0.1 g of the crude powder
dissolved in 1 mL of CH Cl which had thereafter been layered
2
4
.3.2. Heteroannulation catalysis (synthesis of 2-
phenylbenzofuran)
2
2
Under an atmosphere of dry Ar gas, a sample of 2-iodophenol
were heated and reacted under the conditions shown in Table
with 3 mL ethyl acetate. Crystals formed within 72 h.
1
. Products were analysed and identified by a combination of
Route (b): Compound L1H (1.00 mmol, 0.3 g) was dissolved in
GC-MS, GC-FID and NMR spectroscopy [28, 29, ESI†].
1
0
5 ml EtOH (95%). A sample of Cu(NO ) •6H O (1.00 mmol,
3 2 2
.187 g) was then added to this mixture at RT; this
combination was then stirred for 12 h. A green coloured
precipitate, which formed during the reaction period, was
5
. Acknowledgements
isolated by a gravity filtration and dried on a rotary evaporator The authors are indebted to the Faculty of Science of Ryerson
(
Yield: 0.19 g; 90%).
University and NSERC for support of this work. Further
financial support from the MINECO of Spain (RYC-2011-08451,
-
1
IR (KBr cm ): 2926 (m), 1626 (s), 1487 (s), 1338 (m), 1216 (m), CTQ2013-40591-P, CTQ2014-51912-REDC, CTQ2016-75986-P
126 (m), 1076 (m), 1013 (m), 755 (s), 687 (s), 538 (m), 458 and CTQ2013-40619-P) and the Gobierno del Principado de
Asturias (project GRUPIN14-006) is gratefully acknowledged.
1
(w).
-
4
UV/Vis. (c = 1
× 10 g/mL: CH Cl ): λ = 348 nm (ε = 15312).
2 2 max
Notes and references
Elemental Analysis calc’d. for C H N O Cu (%): C 48.36, H ‡ see Figure S1.
16
17
4
5
3
.84, N 13.34; found: C 48.35, H 3.86, N 13.16.
§
M. Taghvaee and R. A. Gossage, unpublished results.
4
.2.5. Synthesis of Complex 5
§§ The use of p-nitrobenzaldehyde in lieu of 7 lead to slightly
improved conversion (49%).
In a 100 mL round-bottomed flask containing 20 mL of 95%
EtOH, was placed compound L2H (0.7 mmol, 0.25 g); stirring
was then initiated until complete dissolution of all solids. The
1
(a) M. E. van der Boom and D. Milstein, Chem. Rev., 2003,
03, 1759; (b) M. Albrecht and G. van Koten, Angew. Chem.
1
resulting colourless mixture was then treated with CuCl •2H O
2
2
Int. Ed., 2001, 40, 3750; (c) K. J. Szabó and O. Wendt (Eds.),
Pincer and Pincer-type Complexes: Applications in Organic
Synthesis and Catalysis, Wiley, Weinheim, 2014; (d) G. van
Koten and D. Milstein (Eds.), Top. Organomet. Chem., 2013,
(0.17 g, 1.00 mmol) which was added at RT. Stirring was
continued for a further 12 h (RT). The resulting green-coloured
precipitate was isolated by gravity filtration, washed with
diethyl ether (3 × 5 mL) and dried on a rotary evaporator
4
0
; (e) D. Morales-Morales and C. M. Jensen (Eds.), The
Chemistry of Pincer Compounds, Elsevier, Amsterdam, 2007;
f) G. van Koten, Pure Appl. Chem., 1989, 61, 1681; (g) S.
(Yield: 82%, 0.37 g). The powdered product was crystallized
(
from a sealed vial by dissolving 0.2 g of the powder in 2 mL of
CH Cl2 and then layering with Et O (5 mL) and leaving
Murugesan and K. Kirchner, Dalton Trans., 2016, 45, 416; (h)
M. Font and X. Ribas, Top. Organomet. Chem., 2016, 54, 269;
2
2
(i) M. Yamashita, Bull. Chem. Soc. Jpn., 2016, 89, 269; (j) G.
Bauer and X. Hu, Inorg. Chem. Front., 2016, , 741.
undisturbed for approximately 72 h.
3

8
ACCEPTED MANUSCRIPT
2
P. A. Chase, R. A. Gossage and G. van Koten, Top.
Organomet. Chem., 2016, 54, 1.
MacInnis, S. A. McFarland, E. J. New and R. A. Gossage, Med.
Chem. Commun., 2011, , 274.
2
3
4
G. van Koten, Top. Organomet. Chem., 2013, 40, 1.
K. Farrell and M. Albrecht, Top. Organomet. Chem., 2016, 54
11 A. Decken, R. A. Gossage and P. N. Yadav, Can. J. Chem.,
2005, 83, 1185.
,
4
5.
(a) C. J. Moulton and B. L. Shaw, J. Chem. Soc., Dalton Trans.,
976, 1020; (b) G. van Koten, J. T. B. H. Jastrzebski, J. G.
Noltes, A. L. Spek and J. C. Schoone, J. Organomet. Chem.,
978, 148, 233; (c) C. S. Ceaser and W. C. Kaska, Inorg. Chim.
12 (a) G. Bauer, M. D. Wodrich, R. Scopelliti and X. Hu,
Organometallics, 2015, 34, 289; (b) G. Bauer, C. W. Cheung
and X. Hu, Synthesis, 2015, 47, 1726; (c) G. T. Venkanna, H.
5
1
D. Arman and Z. J. Tonzetich, ACS Catal., 2014, 4, 2941; (d)
1
Q.-H. Deng, R. L. Melen and L. H. Gade, Acc. Chem. Res.,
2014, 47, 3162; (e) G. C. Hargaden, T. P. O’Sullivan and P. J.
Guiry, Org. Biomol. Chem., 2008, 6, 562; (f) H. Liu, J. He, Z.
Acta, 1978, 30, L325; (d) G. van Koten, K. Timmer, J. G.
Noltes and A. L. Spek, J. Chem. Soc., Chem. Commun., 1978,
2
50.
Liu, Z. Lin, G. Du, S. Zhang and X. Li, Macromolecules, 2013,
46, 3257; (g) Q.-H. Deng, C. Rettenmeier, H. Wadepohl and L.
H. Gade, Chem. Eur. J., 2014, 20, 93; (h) H. Nishiyama,
Chemistry & Chemical Industry, 2016, 69, 031; (i) S. J.
Malthus, S. A. Cameron and S. Brooker, Coord. Chem. Rev.,
2016, 316, 125; (j) S. Werkmeister, J. Neumann, K. Junge and
M. Beller, Chem. Eur. J., 2015, 21, 12226; (k) C. Yoo, M. J.
Ajitha, Y. Jung and Y. Lee, Organometallics, 2015, 34, 4305;
(l) C. A. Rettenmeier, J. Wenz, H. Wadepohl and L. H. Gade,
Inorg. Chem., 2016, 55, 8214; (m) Y.-Q. Zhong, H.-Q. Xiao and
X.-Y. Yi, Dalton Trans., 2016, 45, 18113.
6
7
8
(a) K. J. Szabó, Top. Organomet. Chem., 2013, 40, 203; (b) M.
Albrecht and M. M. Linder, Dalton Trans., 2011, 40, 8733.
G. R. Freeman and J. A. G. Williams, Top. Organomet. Chem.,
2
013, 40, 89.
(a) R. L. Melen, Dalton Trans., 2013, 42, 16449; (b) F. T.
Edelmann, Adv. Organomet. Chem., 2013, 61, 55; (c) A. A.
Mohamed, Coord. Chem. Rev., 2010, 254, 1918; (d) C. Jones,
Coord. Chem. Rev., 2010, 254, 1273; (e) A. A. Trifonov, Coord.
Chem. Rev., 2010, 254, 1327; (f) F. T. Edelmann, Struct.
Bonding, 2010, 137, 109; (g) M. P. Coles, Chem. Commun.,
2
2
1
1
009, 3659; (h) F. T. Edelmann, Chem. Soc. Rev., 2009, 38
253; (i) P. W. Roesky, Z. Anorg. Allg. Chem., 2006, 632
918; (j) P. W. Roesky, Z. Anorg. Allg. Chem., 2003, 629
,
,
,
13 (a) R. A. Gossage, Dalton Trans., 2011, 40, 8755; (b) K.
Herasymchuk, J. Huynh, A. J. Lough, L. Roces Fernández and
R. A. Gossage, Synthesis, 2016, 48, 2121.
881; (k) R. Kempe, Angew. Chem. Int. Ed., 2000, 39, 468; (l) 14 (a) A. I. Meyers, J. Org. Chem., 2005, 70, 6137; (b) A. I.
T. S. Li, J. Jenter and P. W. Roesky, Struct. Bonding, 2010,
37, 165; (m) L. H. Gade, Acc. Chem. Res., 2002, 35, 575; (n)
R. Kempe, H. Noss and T. Irrgang, J. Organomet. Chem.,
002, 647, 12; (o) L. H. Gade, Chem. Commun., 2000, 173; (p)
Meyers, J. Heterocyclic Chem., 1998, 35, 991; (c) A. I. Meyers,
Acc. Chem. Res., 1978, 11, 375; (d) J. A. Frump, Chem Rev.,
1971, 71, 483; (e) R. H. Wiley and L. L. Bennett, Jr., Chem.
Rev., 1948, 44, 447.
1
2
M. D. Fryzuk, V. Hoffman, J. E. Kickham, S. J. Rettig and S. 15 (a) R. Xifra, X. Ribas, A. Llobet, A. Poater, M. Duran, M. Solá,
Gambarotta, Inorg. Chem., 1997, 36, 3480; (q) J. Jenter and
P. W. Roesky, New J. Chem., 2010, 34, 1541; (r) B. Luo, B. E.
Kucera and W. L. Gladfelter, Polyhedron, 2006, 25, 279; (s) B.
T. D. P. Stack, J. Benet-Buchholz, B. Donnadieu, J. Mahía and
T. Parella, Chem. Eur. J., 2005, 11, 5146; (b) D.-W. Tan, J.-B.
Xie, Q. Li, H.-X. Li, J.-C. Li, H.-Y. Li and J.-P. Lang, Dalton
Trans., 2014, 43, 14061; (c) D. I. Bezuidenhout, G. Kleinhans,
G. Guisado-Barrios, D. C. Liles, G. Ung and G. Bertrand, Chem.
Commun., 2014, 50, 2431; (d) P. Zabierowski, D. Matoga and
Luo, B. E. Kucera and W. L. Gladfelter, Polyhedron, 2010, 29
2
,
795; (t) M. Kahnes, H. Görls and M. Westerhausen,
Organometallics, 2010, 29, 3490; (u) J. L. Cryder, A. J.
Killgore, C. Moore, J. A. Golen, A. L. Rheingold and C. J. A.
Daley, Dalton Trans., 2010, 39, 10671.
(a) X. Gu, L. Zhang, X. Zhu, S. Wang, S. Zhou, Y. Wei, G. Zhang,
X. Mu, Z. Huang, D. Hong and F. Zhang, Organometallics,
W. Nitek, RSC Adv., 2015, 5, 25911; (e) S.-Q. Bai, L. Lin Koh
and T. S. A. Hor, Inorg. Chem., 2009, 48, 1207; (f) D. C. Sauer
and H. Wadepohl, Polyhedron, 2014, 81, 180; (g) M. Melník,
M. Kabeŝová, M. Dunaj-Jurčo and C. E. Holloway, J. Coord.
Chem., 1997, 41, 35.
9
2
015, 34, 4553; (b) L. Yang, X. Zhang, P. Mao, Y. Xiao, H. Bian,
J. Yuan, W. Mai and L. Qu, RSC Adv., 2015, 5, 25723; (c) J. J. 16 (a) P. Sathyadevi, P. Krishnamoorthy, R. R. Butorac, A. H.
Davidson, J. C. DeMott, C. Douvris, C. M. Fafard, N.
Bhuvanesh, C.-H. Chen, D. E. Herbert, C. Lee, B. J. McCulloch,
Cowley and N. Dharmaraj, Inorg. Chim. Acta, 2014, 409, 185;
(b) D. Wang, S. V. Lindeman and A. T. Fiedler, Eur. J. Inorg.
Chem., 2013, 4473; (c) X. Hu, Chem. Sci., 2011, 2, 1867; (d) I.
Martí, A. Ferrer, J. Escorihuela, M. I. Burgette and S. V. Luis,
Dalton Trans., 2014, 41, 6764.
B. M. Foxman and O. V. Ozerov, Inorg. Chem., 2015, 54
2
Chem. Sci., 2013,
,
916; (d) J. C. DeMott, N. Bhuvananesh and O. V. Ozerov,
4
, 642; (e) A. A. Vasil’ev, V. Yu. Aleksenko,
D. V. Aleksanyan and V. A. Kozlov, Mendeleev Commun., 17 (a) M. Gómez, G. Muller and M. Rocamora, Coord. Chem.
013, 23, 344; (f) S. Venkat Ramani, M. E. Pascualini, I. Rev., 1999, 193 195, 769; (b) R. A. Gossage, P. N. Yadav, T. D.
Ghiviriga, K. A. Abboud and A. S. Veige, Polyhedron, 2013, 64 MacInnis, J. W. Quail and A. Decken, Can. J. Chem., 2009, 87
77; (g) S. Schneider, J. Meiners and B. Askevold, Eur. J. 368; (c) R. A. Gossage, H. A. Jenkins and P. N. Yadav,
Tetrahedron Lett., 2004, 45, 7689 (corrigendum: 2005, 46
2
-
,
,
3
Inorg. Chem., 2012, 412; (h) T. D. Nixon and B. D. Ward,
Chem. Commun., 2012, 48, 11790; (i) J. C. Peters, S. B.
,
5243); (d) F. J. Baerlocher, R. Bucur, A. Decken, C. R. Eisnor,
R. A. Gossage, S. M. Jackson, L. Jolly, S. L. Wheaton and R. S.
Wylie, Aust. J. Chem., 2010, 63, 47; (e) P. N. Yadav, T. M.
Barclay and R. A. Gossage, J. Nepal Chem. Soc., 2011, 28, 54;
(f) I. del Río and R. A. Gossage, Acta Cryst., 2009, E65, m103.
Harkins, S. D. Brown and M. W. Day, Inorg. Chem., 2001, 40
5
,
083; (j) S. E. Durran, M. R. J. Elsegood, S. R. Hammond and
M. B. Smith, Dalton Trans., 2010, 39, 7136; (k) P. M. Perez
Garcia, T. Di Franco, A. Epenoy, R. Scopelliti and X. Hu, ACS
Catal., 2016,
Hossein Bagi, T. S. Wierenga, M. G. Gardiner and A. J. Canty,
ACS Catal., 2016, , 60; (m) T. Di Franco, M. Stojanovic, S. C. 19 (a) L. J. Farrugia, J. Appl. Cryst., 2012, 45, 849; (b) L. J.
Keller, R. Scopelliti and X. Hu, Helv. Chim. Acta, 2016, 99
30.
6
, 258; (l) A. Ariafard, H. Ghari, Y. Khaledi, A. 18 L. Yang, D. R. Powell and R. P. Houser, Dalton Trans., 2007,
955.
6
,
Farrugia, J. Appl. Cryst., 1997, 30, 565.
8
20 (a) A. J. Hallett, T. M. O’Brien, E. Carter, B. M. Kariuki, D. M.
Murphy and B. D. Ward, Inorg. Chim. Acta, 2016, 441, 86; (b)
N. J. Hurley, J. J. Hayward, J. M. Rawson, M. Murrie and M.
Pilkington, Inorg. Chem., 2014, 53, 8610; (c) W.-G. Jia, D.-D.
Li, Y.-C. Dai, H. Zhang, L.-Q. Yan, E.-H. Sheng, Y. Wei, X.-L. Mu
1
0 P. N. Yadav, R. E. Beveridge, J. Blay, A. R. Boyd, M. W.
Chojnacka, A. Decken, A. A. Deshpande, M. G. Gardiner, T.
W. Hambley, M. J. Hughes, L. Jolly, J. A. Lavangie, T. D.

9
ACCEPTED MANUSCRIPT
and K.-W. Huang, Org. Biomol. Chem., 2014, 12, 5509; (d) X.-
Org. Chem., 2014, 7193; (j) C.-H. Lin, Y.-J. Wang and C.-F. Lee,
Eur. J. Org. Chem., 2010, 4368; (k) M. Wu, J. Mao, J. Guo and
S. Ji, Eur. J. Org. Chem., 2008, 4050; (l) J.-H. Li, J.-L. Li, D.-P.
Wang, S.-F. Pi, Y.-Z. Xie, M.-B. Zhang and X.-C. Hu, J. Org.
Chem., 2007, 72, 2053; (m) K. Okura, M. Furuune, M. Enna,
M. Miura and M. Nomura, J. Org. Chem., 1993, 58, 4716; (n)
G. J. S. Doad, J. A. Barltrop, C. M. Petty and T. C. Owen,
Tetrahedron Lett., 1989, 30, 1597; (o) C. E. Castro, E. J.
Gaughan and D. C. Owsley, J. Org. Chem., 1966, 31, 4071.
T. Yang, H. Wu, S.-J. Ma, J.-J. Hu and Y.-M. Wang, Trans. Met.
Chem., 2011, 36, 403; (e) J. Wang, B. Djukic, J. Cao, A.
Alberola, F. S. Razavi and M. Pilkington, Inorg. Chem., 2007,
4
6
, 8560; (f) Y.-M. Zhang, L. Xian, T.-B. Wei and K.-B. Yu, J.
Chem. Res. (S), 2003, 798; (g) A. N. Vedernikov, P. Wu, J. C.
Huffman and K. G. Caulton, Inorg. Chim. Acta, 2002, 330
03; (h) G. Mugesh, H. B. Singh and R. J. Butcher, Eur. J.
Inorg. Chem., 2001, 669; (i) P. Segl’a, M. Koman and T. G.
,
1
Gowiak, J. Coord. Chem., 2000, 50, 105; (j) D. A. Evans, M. C. 29 (a) K. S. Sindhu and G. Anilkumar, RSC Adv., 2014,
Kozlowski, J. A. Murray, C. S. Burgey, K. R. Campos, B. T.
Connell and R. J. Staples, J. Am. Chem. Soc., 1999, 121, 669;
4
, 27867;
(b) H. Plenio, Angew Chem. Int. Ed., 2008, 47, 6954; (c) F.
Monnier and M. Taillefer, Angew Chem. Int. Ed., 2009, 48
,
(
von Schnering, Chem. Ber./Recueil, 1997, 130, 1309.
k) R. W. Saalfrank, M. Decker, F. Hampel, K. Peters and H. G.
6954; (d) J. Liu, F. Dai, Z. Yang, S. Wang, K. Xie, A. Wang, X.
Chen and Z. Tan, Tetrahedron Lett., 2012, 53, 5678.
1 (a) P. Comba, T. W. Hambley and B. Martin, Molecular 30 (a) A. Khan, A. J. Lough, R. A. Gossage and D. A. Foucher,
2
rd
Modeling of Inorganic Compounds (3 Ed.), Wiley-VCH,
Weinheim, 2009; (b) P. Comba and M. Kerscher, Coord.
Chem. Rev., 2009, 253, 564; (c) R. J. Deeth, A. Anastasi, C.
Diedrich and K. Randell, Coord. Chem. Rev., 2009, 253, 795;
Dalton Trans., 2013, 42, 2469; (b) M. W. Chojnacka, A. J.
Lough, R. S. Wylie and R. A. Gossage, J. Molec. Struct., 2011,
991, 158; (c) A. Petrov, R. C. Jones, D. G. Vaughan, A. J. Lough
and R. A. Gossage, Crystals, 2011, 1, 229.
(
d) D. C. Young, Computational Chemistry – A Practical Guide 31 (a) R. C. Jones, K. Hermasymchuk, T. Mahdi, A. Petrov, S.
for Applying Techniques to Real World Problems, Wiley-
Interscience, Toronto, 2001.
2 A. W. Addison, T. N. Rao, J. Reedijk, J. van Rijn and G. C.
Verschoor, J. Chem. Soc., Dalton Trans., 1984, 1349.
Resanović, D. G. Vaughan, A. J. Lough, J. W. Quail, B. D.
Koivisto, R. S. Wylie and R. A. Gossage, Org. Biomol. Chem.,
2013, 11, 3484; (b) J. W. Quail and R. A. Gossage, Proc. Nova
Scotian Inst. Sci., 2011, 46, 175.
2
2
3 For example: (a) Q.-X. Liu, Y. Bo, X.-J. Zhao, Z.-X. Zhao, J.-H. 32 Spartan 10.0, Wavefunction Inc., Irvine CA (U.S.A.).
Wang and X.-G. Wang, CrystEngComm., 2014, 16, 1950; (b)
X. Xu, Z. Xi, W. Chen and D. Wang, J. Coord. Chem., 2007, 60
297; (c) P.-N. Wang, C.-W. Yeh, H.-A. Tsai, J.-C. Wang and
M.-C. Suen, Acta Cryst., 2011, E67, m881; (d) K. Fujisawa, R.
Kanda, Y. Miyashita and K. Okamoto, Polyhedron, 2008, 27
432; (e) I. V. Morozov, V. N. Serezhkin and S. I. Troyanov,
,
2
,
1
Russ. Chem. Bull., Int. Ed., 2008, 57, 439; (f) I. V. Morozov, V.
N. Serezhkin and S. I. Troyanov, Russ. Chem. Bull., Int. Ed.,
2
009, 58, 2407; (g) C. C. Addison, N. Logan, S. C. Wallwork
and C. D. Garner, Quart. Rev. Chem. Soc., 1971, 25, 289.
4 (a) C. Bonnier, D. D. Machin, O. Abdi and B. D. Koivisto, Org.
Biomol. Chem., 2013, 11, 3756; (b) C. Bonnier, D. D. Machin,
O. K. Abdi, K. C. D. Robson and B. D. Koivisto, Org. Biomol.
Chem., 2013, 11, 7011.
5 K. Matyjaszewski in K. Matyjaszewski (Ed.), Controlled
Radical Polymerization, American Chemical Society, 1998,
Chapters 1 and 16.
2
2
2
2
6 L. Henry, Compt. Rendus, 1895, 120, 1265.
7 (a) C. Palomo, M. Oiarbide and A. Laso, Eur. J. Org. Chem.,
2
007, 2561; (b) S. E. Milner, T. S. Moody and A. R. Maguire,
Eur. J. Org. Chem., 2012, 3059; (c) L. Mei, Y. Hao, Z. J. Hai, H.
K. Liang and P. W. Min, Res. Chem. Intermed., 2009, 35, 123;
(
d) S. O’Reilly and P. J. Guiry, Synthesis, 2014, 46, 722; (e) F.
A. Luzzio, Tetrahedron, 2001, 57, 915; (f) A. P. Thankachan, S.
Asha, K. S. Sindhu and G. Anilkumar, RSC Adv., 2015,
2179; (g) D. Ran, T. Shen, X. Zhou, J. Li, F. Cui, C. Ma and Q.
5
,
6
Song, Russ. J. Org. Chem., 2013, 49, 849; (h) G. Desimoni, G.
Faita and K. A. Jørgensen, Chem. Rev., 2006, 106, 3561; (i) V.
A. Pavlov and T. N. Pavlova, Russ. Chem. Rev., 2010, 79, 881.
8 (a) M. J. Moure, R. SanMartin and E. Domínguez, Adv. Synth.
Catal., 2014, 356, 2070; (b) D.-D. Qin, W. Chen, X. Tang, W.
Yu, A.-A. Wu, Y. Liao and H.-B. Chen, Asian J. Org. Chem.,
2
2
016, 5, 1345; (c) P. Saejuueng, C. G. Bates and D.
Venkataraman, Synthesis, 2005, 1706; (d) C. G. Bates, P.
Saejuueng, J. M. Murphy and D. Venkataraman, Org. Lett.
2
002, 4, 4727; (e) E. A. Jaseer, D. J. C. Prasad and G. Sekar,
Tetrahedron, 2010, 66, 2077; (f) R. Wang, S. Mo, Y. Li and Z.
Shen, Adv. Synth. Catal., 2011, 353, 713; (g) A. Arcadi, F.
Blesi, S. Cacchi, G. Fabrizi, A. Goggiamani and F. Marinelli,
Tetrahedron, 2013, 69, 1857; (h) A. Arcadi, F. Blesi, S. Cacchi,
G. Fabrizi and A. Goggiamani Tetrahedron Lett., 2011, 52,
5149; (i) S. Indu, P. Subramanian and K. P. Kaliappan, Eur. J.

ACCEPTED MANUSCRIPT
Highlights for review
New Pincer imido complexes containing an oxazoline unit have been synthesises and fully characterised
Materials are active catalysts in heteroannulation chemistry