Synthesis and characterization of azidobipyridyl ruthenium complexes and their click chemistry derivatives

Article abstract of DOI:10.1002/ejic.201201419

The ligand 4-azido-2,2′-bipyridyl (1) has been used to prepare 1,2,3-triazole-substituted ligands through copper-catalyzed alkyne/azide cycloaddition (CuAAC or click chemistry) with phenylacetylene, ethynylferrocene and 2-ethynylpyridine to yield 4-(4-phenyl-1,2,3-triazol-1-yl)- 2,2′-bipyridyl (2a), 4-(4-ferrocenyl-1,2,3-triazol-1-yl)-2,2′- bipyridyl (2b) and 4-[4-(pyridyl-2-yl)-1,2,3-triazol-1-yl]-2,2′-bipyridyl (2c). Complexes of the form [Ru(p-cymene)(Cl)(L)]PF₆ (3, L = 1; 4a, L = 2a; 4b, L = 2b) were then prepared and characterized. We also report the synthesis of the complex of the analogous ligand 4,4′-bisazido-2,2′- bipyridyl (1′), [Ru(p-cymene)(Cl)(1′)]PF₆ (3′). Complexes 4a and 4b were also prepared by an alternative route, whereby 3 undergoes CuAAC coupling with phenylacetylene and ethynylferrocene respectively. Complexes prepared with ligands that are pre-assembled or clicked at the metal show identical ¹H NMR spectra. CuAAC coupling of 3 and 2-ethynylpyridine results in the formation of the complex [Ru(p-cymene)(Cl)(2c)] PF₆ (4c), which contains a coordinatively vacant pyridyltriazole moiety. The reaction of [Ru(p-cymene)(Cl)₂]₂ with pre-assembled 2c results in the formation of the dinuclear complex [{Ru(p-cymene)(Cl)}₂(2c)]·2PF₆ (5), which incorporates ruthenium atoms at both bipyridyl and pyridyltriazole binding domains. The ¹H NMR spectrum of the complex shows two signals for the triazole ring proton as well as duplicate signals for other protons of the bridging ligand, which indicates that 5 is produced as a mixture of diastereoisomers. The complex [{Ru(p-cymene)Cl}₂{di-4-([1-{2, 2′-bipyrid-4-yl}triazol-4-yl]methyl)ether}][PF₆]₂ (7) was also prepared through the coupling of 3 with dipropargyl ether. Copyright

Full text of DOI:10.1002/ejic.201201419

FULL PAPER
DOI:10.1002/ejic.201201419
Synthesis and Characterization of Azidobipyridyl
Ruthenium Complexes and Their “Click” Chemistry
Derivatives
Baljinder S. Uppal,[a] Adam Zahid,[a] and Paul I. P. Elliott*[a]
Keywords: Supramolecular chemistry / Click chemistry / Ruthenium / N ligands
The ligand 4-azido-2,2Ј-bipyridyl (1) has been used to pre-
pare 1,2,3-triazole-substituted ligands through copper-cata-
lyzed alkyne/azide cycloaddition (CuAAC or “click” chemis-
try) with phenylacetylene, ethynylferrocene and 2-ethynyl-
pyridine to yield 4-(4-phenyl-1,2,3-triazol-1-yl)-2,2Ј-bipyridyl
(2a), 4-(4-ferrocenyl-1,2,3-triazol-1-yl)-2,2Ј-bipyridyl (2b)
and 4-[4-(pyridyl-2-yl)-1,2,3-triazol-1-yl]-2,2Ј-bipyridyl (2c).
Complexes of the form [Ru(p-cymene)(Cl)(L)]PF6 (3, L = 1;
4a, L = 2a; 4b, L = 2b) were then prepared and characterized.
We also report the synthesis of the complex of the analogous
ligand 4,4Ј-bisazido-2,2Ј-bipyridyl (1Ј), [Ru(p-cymene)(Cl)-
(1Ј)]PF6 (3Ј). Complexes 4a and 4b were also prepared by an
alternative route, whereby 3 undergoes CuAAC coupling
with phenylacetylene and ethynylferrocene respectively.
Complexes prepared with ligands that are pre-assembled or
“clicked” at the metal show identical 1H NMR spectra.
CuAAC coupling of 3 and 2-ethynylpyridine results in the
formation of the complex [Ru(p-cymene)(Cl)(2c)]PF6 (4c),
which contains a coordinatively vacant pyridyltriazole moi-
ety. The reaction of [Ru(p-cymene)(Cl)2]2 with pre-assembled
2c results in the formation of the dinuclear complex [{Ru(p-
cymene)(Cl)}2(2c)]·2PF6 (5), which incorporates ruthenium
atoms at both bipyridyl and pyridyltriazole binding domains.
1
The H NMR spectrum of the complex shows two signals for
the triazole ring proton as well as duplicate signals for other
protons of the bridging ligand, which indicates that 5 is pro-
duced as a mixture of diastereoisomers. The complex [{Ru(p-
cymene)Cl}2{di-4-([1-{2,2Ј-bipyrid-4-yl}triazol-4-yl]methyl)-
ether}][PF6]2 (7) was also prepared through the coupling of 3
with dipropargyl ether.
Introduction
A desirable convergent route to such architectures would
involve the coupling of discrete preformed complexes into
supramolecular complexes under mild conditions in as few
steps as possible. Such an approach would require a cou-
pling reaction that is highly efficient and high yielding and
for which the required functional groups for the coupling
reaction can be easily incorporated into the periphery of
the metal-complex components. With such a methodology
in place and a library of suitably derivatized transition-
metal-complex components available, this would allow fac-
ile access to supramolecular architectures with an extraordi-
nary diversity of structure.
A series of such candidate coupling reactions exists and
falls under the umbrella term of “click” chemistry.[5,6] These
reactions are highly efficient, selective and high yielding, are
tolerant of a wide range of other functional groups, proceed
in a variety of solvents including protic media, and require
minimal work-up and product purification. The most
prominent of these reactions is the copper-catalyzed alkyne/
azide cycloaddition (CuAAC) to form 1,4-disubstituted-
1,2,3-triazoles. The reaction has attracted enormous interest
in the areas of organic synthesis, materials and polymer sci-
ence[7–9] and the modification of biological macromole-
cules.[10,11] Alkyne and azide starting materials are also
either readily commercially available or have facile routes
to their synthesis. Curiously though, CuAAC only relatively
The synthesis and preparation of supramolecular archi-
tectures containing photo- and redox-active transition-
metal centres has become an area of intense interest.[1–3]
The strong interest in this area stems from the potential
application of these materials for the modelling of energy
transfer processes in biological photosynthesis, the develop-
ment of new light harvesting photocatalysts and new mate-
rials for solar energy conversion. The traditional method
for the preparation of such metallosupramolecular materi-
als has relied on the preparation of bridging ligands with
multiple coordination sites into which metal centres can
subsequently be incorporated. This methodology suffers
from key disadvantages with problems in controlling the
selectivity of metal binding when, for example, hetero-
metallic complexes are required and where the bridging li-
gand is nonsymmetric. Extended ligand-based approaches
have also been championed in which complexes are pre-
pared and modified at their periphery to graft a second
binding domain onto the complex.[4]
[a] Department of Chemical and Biological Sciences, University of
Huddersfield,
Queensgate, Huddersfield, HD1 3DH, UK
E-mail: p.i.elliott@hud.ac.uk
Homepage: http://www.hud.ac.uk
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201201419.
Eur. J. Inorg. Chem. 2013, 2571–2579
2571
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
FULL PAPER
recently began to attract significant interest from the inor- functional supramolecular architectures from alkyne- and
ganic community for use in ligand design[12–36] and for the azide-functionalized transition-metal-complex components.
construction of self-assembled supramolecular architec-
tures.[37–39] This area has recently been the subject of a com-
prehensive review.[40]
Results and Discussion
Therefore, we have begun to explore the use of CuAAC
towards such a modular approach for the construction of
supramolecular architectures. A few reports have appeared
on the CuAAC modification of transition-metal complexes
with peripheral alkyne functionalities. Ren first demon-
strated the peripheral modification of alkynyl-substituted
diruthenium complexes.[41,42] More recently, Sierra and co-
workers reported the formation of dinuclear complexes
from alkynyl-substituted Fischer carbene complexes of
pentacarbonylchromium(0) by CuAAC coupling with bis-
azide spacers including bis(azidomethyl)ferrocene.[43] Sim-
ilar results have been obtained with analogous pentacarb-
onyltungsten(0) complexes.[44] Constable et al. have demon-
strated the coupling of azidosugars with alkyne-function-
alized bipyridyl ligands and the preparation of their ruthe-
nium complexes.[45]
The comparable use of azido-functionalized complexes is
far less developed. Azidoferrocenes have been used for the
preparation of ferrocenyl triazoles, which have subsequently
been used as monodentate ligands, for example.[12] Fallahp-
our has developed routes to azide derivatives of bipyridyl
and terpyridyl[46–48] ligands and demonstrated the forma-
tion of azidoterpyridyl complexes. However, attempts to
prepare their ruthenium complexes led to azide reduction
to the amine under the conditions used. Whilst we were
carrying out the work presented in this paper, Aukauloo
and co-workers utilized an azido bipyridyl ligand to prepare
a chromophore tagged ligand and its [Ru(bpy)2] complex
(bpy = 2,2Ј-bipyridyl) and showed that there is efficient
electron transfer through the triazole linker.[49] However,
there remains very little in the literature regarding the
CuAAC functionalization of complexes with coordinated
azide-substituted ligands. Chitre et al. recently reported the
synthesis of a homoleptic ruthenium(II) 4,4Ј-bisazido-2,2Ј-
bipyridyl complex but were unable to affect subsequent
CuAAC derivatization owing to decomposition of the com-
plex under the reaction conditions.[50] Beyond ferrocene, the
first example of CuAAC modification of an azide-function-
alized complex that we are aware of was demonstrated by
Constable and co-workers. Using bis(azidoterpyridyl)-
iron(II), the azide-functionalized ligand, attached to the
metal centre under mild conditions, can subsequently un-
dergo CuAAC modification.[51]
The monoazido-substituted ligand 4-azido-2,2Ј-bipyridyl
(1) was prepared from its nitro-substituted analogue by re-
action with sodium azide in dimethylformamide (DMF) at
100 °C in a procedure modified from that reported pre-
viously by Fallahpour.[52] After purification by flash
chromatography, 1 was isolated as a pale yellow solid in
1
excellent yield. The H NMR spectrum of 1 in [D]chloro-
form exhibits a total of seven resonances, typical of a 4-
substituted bpy ligand. The presence of the azide group is
confirmed by the observation of a peak at 2115 cm–1 in the
infrared spectrum. 4,4Ј-Diazido-2,2Ј-bipyridyl (1Ј) was
similarly prepared from 4,4Јdinitro-2,2Ј-bipyridyl, again, in
1
excellent yield. The H NMR spectrum of 1Ј in [D]chloro-
form exhibits three resonances, which reflects the symmetry
of the ligand, and the presence of the azide groups is again
confirmed by a peak at 2117 cm–1 in the infrared spectrum.
Having isolated and characterized ligands 1 and 1Ј, we
decided to investigate the use of these azides in CuAAC
reactions. The reaction of 1 with phenylacetylene or ethyn-
ylferrocene in 1:1 water/tetrahydrofuran (THF) in the pres-
ence of copper(II) sulfate and sodium ascorbate resulted in
the formation of the triazole-substituted ligands 2a and 2b,
1
respectively, in moderate yields (Scheme 1). The H NMR
spectra of 2a and 2b show characteristic singlet resonances
for the proton of the triazole ring at δ = 8.48 and 8.18 ppm,
respectively. For 2b, the resonances of the substituted cyclo-
pentadienyl (Cp) ring of the ferrocene moiety appear at δ =
4.82 and 4.37 ppm, and the unsubstituted Cp ring gives rise
to a singlet at δ = 4.12 ppm. Formation of the cycloaddition
triazoles is also confirmed by the absence of the azide
Here, we present recent results on the coordination
chemistry of mono- and bis(azido)bipyridyl ligands in their
[Ru(p-cymene)Cl]+ complexes. Subsequently, we show the
first example of CuAAC modification of a ruthenium com-
plex with pendant azide functionalities. Such complexes will
have applications as important synthons for the preparation
of functional luminescent molecular devices and solar-cell
dyes for example. Therefore, we have made some of the first
steps towards the goal of the development of a general
Scheme 1. Synthesis of 4-azido-2,2Ј-bipyridyl (1) and subsequent
CuAAC derivatives, (a) NaN3, DMF, 100 °C, (b) phenylacetylene,
CuSO4, sodium ascorbate, 1:1 THF/water, r.t., (c) ethynylferrocene,
CuSO4, sodium ascorbate, 1:1 THF/water, r.t., (d) 2-ethynylpyr-
click-chemistry-based methodology for the construction of idine, CuSO4, sodium ascorbate, 1:1 THF/water, r.t.
Eur. J. Inorg. Chem. 2013, 2571–2579
2572
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
FULL PAPER
stretch in the infrared spectra of the products. The reaction NMR spectrum exhibits two closely overlapping doublets,
with 2-ethynylpyridine resulted in the formation in good which correspond to the methyl groups of the isopropyl
yield of the heteroditopic ligand 2c, which has bpy and pyr- group of the cymene ligand at δ = 1.04 and 1.03 ppm and
idyltriazole binding domains. Its 1H NMR spectrum exhib- shows that they are not magnetically equivalent. This is pre-
its a singlet for the triazole ring proton at δ = 8.91 ppm, sumably due to hindered rotation of the isopropyl group
and a further 11 signals are evident for the protons of the and the aforementioned asymmetry of the complex is due
bipyridyl domain and the pyridyl ring appended to the tri- to the presence of ligand 1.
azole. These were assigned by COSY and NOESY spec-
troscopy.
The complex [Ru(p-cymene)Cl(1Ј)]PF6 (3Ј) was prepared
by an identical procedure to that for 3. Similarly, a charac-
CuAAC coupling of 1Ј with phenyl acetylene and 2-eth- teristic azide stretch is observed in the infrared spectrum at
1
ynylpyridine appeared to similarly result in their triazole 2125 cm–1. The H NMR spectrum shows resonances for
products, however, these proved to be rather insoluble and the bpy protons at δ = 9.15, 7.94 and 7.37 ppm, and the
therefore extremely difficult to characterize. The reaction of arene signals appear at δ = 5.90 and 5.69 ppm. Complexes
1Ј with ethynylferrocene to produce the desired bis(ferro- 3 and 3Ј exhibit similar features in their UV/Vis absorption
cenyltriazolyl)bpy ligand proved unsuccessful and no prod- spectra with intense ligand-based absorptions at around
uct was isolable despite several attempts under various con- 300 nm with less intense metal-to-ligand charge transfer
ditions. It is possible that the failure of this reaction is due (MLCT) based absorptions tailing off towards 450 nm (Fig-
to decomposition of the diazido starting material.
ure 1). A slight redshift in the absorption profile of 3Ј rela-
We then began to explore the coordination chemistry of tive to that of 3 is observed owing to the presence of the
these new ligands. [Ru(p-cymene)(Cl)2]2 was stirred with li- second azide moiety. A single-crystal X-ray structure was
gand 1 in methanol at room temperature, which led to a determined for the complex but unfortunately this was not
bright yellow solution and the complex [Ru(p-cymene)(1)- of suitable quality for publication. Atomic coordinates and
–
Cl]+ was subsequently isolated as its PF6 salt (3, a plot of the molecular structure are included in the Sup-
Scheme 2). The infrared spectrum of 3 shows a characteris- porting Information for the curious reader for information
tic peak corresponding to the azide stretch at 2124 cm–1, only. Further crystals of X-ray diffraction quality could not
which is shifted by 9 cm–1 relative to that of the non-coordi- be obtained.
1
nated ligand. The H NMR spectrum of the complex con-
The analogous complexes of ligands 2a and 2b were also
tains seven resonances in the aromatic region for the bpy prepared by the same route as that for the preparation of 3
ligand. The signals for the nonsubstituted pyridyl ring are and 3Ј (Scheme 3). Therefore, the addition of these ligands
all deshielded on coordination as is the H-6 proton of the
azide-substituted ring, which appears at δ = 9.15 ppm. The
resonances for the arene protons of the cymene ligand ap-
pear at δ = 5.91 and 5.71 ppm. These signals appear as trip-
1
lets rather than a pair of doublets as in the H NMR spec-
trum of the precursor [Ru(p-cymene)(Cl)2]2, which shows
that the symmetry of the cymene has been broken by the
asymmetry of the coordinated ligand 1. In addition, the 1H
Figure 1. UV/Vis absorption spectra of complexes in acetonitrile
solutions.
Scheme 2. Synthesis of ruthenium complexes of ligands 1 and 1Ј.
Scheme 3. Synthesis of complexes 4a–c by reaction of [Ru(p-cymene)(Cl)2]2 with ligands 2a and 2b or by CuAAC coupling with phenyl-
acetylene, ethynylferrocene or 2-ethynylpyridine, respectively: (a) i) [Ru(p-cymene)(Cl)2]2, MeOH, r.t., 2a or 2b. ii) NaPF6. (b) Alkyne,
CuSO4(aq), sodium ascorbate, 1:1 THF/water.
Eur. J. Inorg. Chem. 2013, 2571–2579
2573
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
FULL PAPER
to [Ru(p-cymene)(Cl)2]2 led to the isolation of the com- gests that the stereochemistry of the first ruthenium centre
plexes [Ru(p-cymene)(2a)Cl]PF6 (4a) and [Ru(p-cym- to coordinate to the ligand does not influence the chirality
1
ene)(2b)Cl]PF6 (4b). Similarly to the H NMR spectrum of adopted at the second ruthenium centre as it coordinates to
3, the spectra of 4a and 4b show nonequivalence of the the other binding domain. Several attempts to separate and
isopropyl methyl groups of the cymene ligand owing to the independently isolate the diastereoisomers by column
asymmetry of the chelating bpy ligands. The 1H resonances chromatography or recrystallization proved unsuccessful.
for the arene protons adjacent to the isopropyl group ap-
pear as an apparent triplet, whereas the resonances for the
arene protons adjacent to the methyl substituent appear as
a doublet for both 4a and 4b. The nonequivalence of the
arene CH positions adjacent to the isopropyl group in each
complex is also evident in the 13C NMR spectra, in which
the signals appear at δ = 87.5 and 87.4 and δ = 87.6 and
87.5 ppm for these positions in 4a and 4b, respectively. Two
13C resonances are also observable for the CH arene posi-
tions adjacent to the methyl group but with a much smaller
separation (these signals are separated by only 0.04 ppm for
4a).
The UV/Vis absorption spectrum for 4a displays similar
features to those of 3 and 3Ј, whereas that of 4b exhibits an
additional absorption owing to the presence of the ferro-
cene moiety at ca. 492 nm and tailing off beyond 550 nm
(Figure 1, Table 1).
Scheme 4. Preparation of the dinuclear complex [{Ru(p-cymene)-
Cl}2(2c)]2+ (5) and the 1-benzyl-4-(pyrid-2-yl)-1,2,3-triazole (pytz)
complex [(p-cymene)RuCl(pytz)]+ (6).
Table 1. UV/Vis absorption data for complexes in acetonitrile solu-
tions.
Complex
Wavelength /nm
3
297, 316, 357, 404
293, 318, 363, 410
297, 330, 367, 406
300, 354, 409, 492
302, 319, 366, 411
297, 305, 367, 416
271, 293, 314, 403
301, 317, 355, 413
3Ј
4a
4b
4c
5
6
7
When [Ru(p-cymene)(Cl)2]2 was allowed to react with an
equivalent of the ditopic ligand 2c, the dinuclear complex 5
–
was formed and it was isolated as its PF6 salt (Scheme 4).
1
Examination of the H NMR spectrum of the complex re-
veals two singlet resonances for the triazole ring proton at
δ = 9.42 ppm, which are assigned because of their lack of
coupling in the COSY spectrum. NMR assignments for the
other ligand protons were then made by using COSY and
NOESY data. Similar duplicate resonances were then found
1
Figure 2. Selected regions of the H NMR spectrum of 5.
By using the ligand 1-benzyl-4-(pyrid-2-yl)-1,2,3-triazole
for the 3- and 6-position protons of the pyridyl ring of the (pytz), we also prepared the complex [Ru(p-cymene)-
bpy domain of the ligand to which the triazole ring is at- Cl(pytz)]PF6 (6) as a spectroscopic model for the pytz-like
tached (Figure 2). A similar split may occur for the 5-posi- domain of 5 by a route analogous to that for the prepara-
1
tion proton but the resonance is obscured through overlap tion of 3 and 4a–b. The H NMR spectrum exhibits four
with resonances of the 4-position protons of the other two resonances for the pyridyl ring at positions close to those
pyridyl rings. The resonance for the isopropyl methine pro- observed for the comparable protons in 5. However, the res-
ton of the cymene ligand of the ruthenium centre occupying onance for the triazole proton appears at δ = 8.55 ppm,
the pyridyl triazole domain appears as two overlapping sep- shielded by 0.87 ppm relative to that of 5. The shift in the
tets and two signals are also observed for the methyl sub- triazole proton resonance is ascribed to the presence of the
stituent. These extra signals arise because of the asymmetry more electron-donating benzyl substituent of the pytz li-
of the binding domains, which renders the two ruthenium gand compared to the bpy moiety that is attached to the
centres chiral. Hence, a total of four isomeric complexes are triazole in 5. Examination of the UV/Vis absorption spectra
possible, which will result in two sets of NMR signals. The of the complexes 4c, 5 and 6 reveals similar features over
equal intensity of the signals for each pair of isomers sug- similar wavelength ranges to each other and those of other
Eur. J. Inorg. Chem. 2013, 2571–2579
2574
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
FULL PAPER
complexes (Figure 1). Therefore, it was not possible to as- the triazole ring protons centred at δ = 9.29 ppm, again,
sign any particular feature of the spectrum of 5 as arising likely owing to the formation of isomeric mixtures of com-
from the bpy- or pytz-like domains based on the data for plexes. However, the other signals in the spectrum do not
the other complexes.
appear to show this kind of duplication. Mass spectrometry
After fully characterizing the ruthenium cymene complex data shows the detection of the dication [7 – 2PF6]+ (m/z =
of ligand 1 and its CuAAC derivatives 2a and 2b, we turned 515). These isomers were again inseparable by conventional
our attention to the reactivity of the ligated azido ligand in chromatographic or recrystallization methods. The UV/Vis
3 toward CuAAC reactions. Thus, complex 3 was shown absorption spectrum of 7 has a very similar appearance to
to undergo CuAAC modification of the outer coordination those of the other triazole derivatives of 3.
sphere with phenylacetylene and ethynylferrocene as an al-
ternative route to complexes 4a and 4b (Scheme 2). In each
case, 3 was mixed with an equivalent of the appropriate
alkyne in 1:1 THF/water in the presence of copper sulfate
1
and sodium ascorbate. The H NMR spectra of 4a and 4b
derived through this alternative route are identical to those
of the same complexes obtained by reaction with the pre-
assembled triazole-containing ligands 2a and 2b. In contrast
to these results, Chitre et al. were unable to isolate triazole
derivatives from CuAAC reaction mixtures containing the
Scheme 5. Preparation of dinuclear complex 7.
complex [Ru(1Ј)3]2+. It is possible that the increased number
of azide groups results in instability of these moieties to-
ward decomposition.
The results presented here clearly show the potential for
the use of CuAAC coupling at the metal centre by utilizing
synthetically versatile synthons such as ruthenium(II) arene
complexes. This paves the way for the site-specific inclusion
of photophysically active ruthenium centres in functional
heteronuclear supramolecular assemblies. Indeed, we are
currently investigating the use of this methodology and
complexes such as 4c as precursors for heterodinuclear dye-
sensitized solar cell pigments and will publish results in this
area in due course.
When 3 is coupled with 2-ethynylpyridine the complex 4c
1
is formed (Scheme 3). The H NMR spectrum of the iso-
lated product shows signals characteristic of the 4-substi-
tuted bpy ligand along with broad signals for the triazole
proton and the third pendant pyridyl ring. Despite treat-
ment of the product with aqueous ammonia, the broad na-
ture of these resonances is most likely due to the coordina-
tion and exchange of paramagnetic copper(II) left over
from the CuAAC reaction mixture. On rewashing a dichlo-
romethane solution of the product with aqueous ammonia
solution to remove the remaining copper ions, the reso-
nances for the protons of the coordinatively vacant pyridyl-
Conclusions
We have successfully demonstrated the CuAAC modifi-
cation of useful ruthenium cymene complexes bearing
azide-functionalized bipyridyl ligands. The choice of the or-
ganometallic starting material [Ru(p-cymene)Cl2]2 allows
the incorporation of azide functionality into the periphery
of a synthetically useful synthon for the preparation of
functionally useful metal complexes under mild condition
without decomposition of the azide group.
1
triazole moiety become resolved in the H NMR spectrum
(Figure 3).
Ruthenium cymene complexes of bipyridyl ligands are
extremely useful synthons for the preparation of heterolep-
tic luminescent complexes, sensitizing dyes for solar-cell ap-
plications and for anticancer drugs. Therefore, the strategies
that we have begun to explore here may pave the way for
the development of a general methodology for the CuAAC
coupling of modular, functionally useful transition-metal-
complex components into supramolecular architectures
with applications in, for example, light-harvesting solar en-
ergy conversion and sensitized photocatalysis.
Figure 3. 1H NMR spectra of 4c a) isolated product before final
ammonia wash b) after final ammonia wash.
Experimental Section
To extend the CuAAC methodology further, we then
coupled 3 with half an equivalent of the dialkyne diprop-
argyl ether to form the dinuclear complex 7 (Scheme 5). The
General: All synthetic procedures were carried out under nitrogen.
[Ru(p-cymene)(Cl)2]2[53] was prepared by a literature procedure. All
1H NMR spectrum of the complex shows two signals for solvents were purchased from either Acros Organics or Aldrich
Eur. J. Inorg. Chem. 2013, 2571–2579
2575
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
FULL PAPER
Chemicals and were used as supplied. NMR spectra were recorded
with Bruker Avance 500 and AMX 400 spectrometers and mass
spectrometry was performed by using a Bruker MicroQ-TOF in-
strument.
lowed by freshly prepared sodium ascorbate solution (1 m aqueous
solution, 1.01 mL) dropwise. The solution was allowed to stir at
room temperature for 1 h. After removal of the THF under vac-
uum, dichloromethane (30 mL) and conc. NH3 (10 mL) were added
to the solution, which was allowed to stir for a further 30 min at
room. The organic phase was washed twice with water (15 mL) and
once with brine (15 mL) and then dried with MgSO4. The solvent
was removed under vacuum, and the product was recrystallized
from dichloromethane and hexane to yield an orange solid (0.087 g,
42%). 1H NMR (CDCl3): δ = 8.83 [d, J = 5.4 Hz, 1 H, py(tz)], 8.74
(ddd, J = 4.7, 1.7 and 0.7 Hz, 1 H, py), 8.69 [d, J = 2.0 Hz, 1 H,
py(tz)], 8.51 (d, J = 7.9 Hz, 1 H, py), 8.18 (s, 1 H, Tz), 8.01 [dd, J
= 5.4 and 2.1 Hz, 1 H, py(tz)], 7.89 (td, J = 7.7 and 1.7 Hz, 1 H,
py), 7.40 (ddd, J = 7.6, 4.7 and 1.2 Hz, 1 H, py), 4.82 (t, J = 1.9 Hz,
2 H, C5H4Fe), 4.37 (t, J = 1.9 Hz, 2 H, C5H4Fe), 4.12 (s, 5 H, Cp)
ppm. 13C NMR (CDCl3): δ = 158.4, 154.9, 151.1, 149.2, 148.5,
144.2, 137.2, 124.5, 121.5, 115.7, 113.9, 110.0, 74.3, 69.7, 69.1, 66.9
ppm. MS (ESI): m/z = 430 [M + Na]+. HRMS: calcd. for
C22H17FeN5Na [M + Na]+ 430.072559; found 430.073052.
4-Azido-2,2Ј-bipyridyl (1):
A mixture of 4-nitro-2,2Ј-bipyridyl
(0.57 g, 2.8 mmol) and NaN3 (1.50 g, 3.85 mmol) was heated in
DMF (10 mL) for 3 h at 100 °C. The dimethylformamide was re-
moved by rotary evaporation, and water (40 mL) was added. The
mixture was extracted with dichloromethane (3ϫ 30 mL), the com-
bined organic phase was dried with MgSO4, and the solvent was
removed. 4-Azido-2,2Ј-bipyridyl was purified by column
chromatography (silica gel, dichloromethane/AcOEt, 1:1) to yield
a yellow solid (0.53 g, 95%) 1H NMR (CDCl3): δ = 8.69 (ddd, J =
4.8, 1.8 and 0.9 Hz, 1 H, 6Ј-H), 8.58 (d, J = 5.4 Hz, 1 H, 6-H), 8.40
(dt, J = 7.8 and 0.9 Hz, 1 H, 4Ј-H), 8.15 (d, J = 2.3 Hz, 1 H, 3-H);
7.83 (td, J = 7.8 and 1.8 Hz, 1 H, 5Ј-H), 7.34 (ddd, J = 7.5, 4.8
and 1.2 Hz, 1 H, 3Ј-H), 6.94 (dd, J = 5.4 and 2.3 Hz, 1 H, 5-H)
ppm. 13C NMR (CDCl3): δ = 160.0, 155.2, 150.5, 149.8, 149.2,
137.1, 124.3, 121.3, 114.2, 111.2 ppm. MS (ESI): m/z = 220 [M +
Na]+. HRMS: calcd for C10H7N5Na [M + Na]+ 220.059366; found
4-[4-(Pyridin-2-yl)-1,2,3-triazol-1-yl]-2,2Ј-bipyridyl (2c): 4-Azido-
2,2Ј-bipyridyl (0.25 g, 1.27 mmol) and 2-ethynylpyridine (0.196 g,
1.90 mmol) were dissolved in THF (30 mL), and water was added
(30 mL). CuSO4 (1 m aqueous solution, 1.27 mL) was added fol-
lowed by freshly prepared sodium ascorbate solution (1 m aqueous
solution 2.54 mL) dropwise. The solution was allowed to stir at
room temperature for 1 h. After removal of the THF under vac-
uum, dichloromethane (30 mL) and conc. NH3 (15 mL) were added
to the solution, which was allowed to stir for a further 30 min at
220.058833. IR (ATR): ν = 2115 cm–1.
˜
4,4Ј-Diazido-2,2Ј-bipyridyl (1Ј): A mixture of 4,4Ј-dinitro-2,2Ј-bi-
pyridyl (0.10 g, 0.4 mmol) and NaN3 (0.25 g, 3.85 mmol) was
heated in dimethylformamide (10 mL) for 3 h at 100 °C. The sol-
vent was removed by rotary evaporation, and water (40 mL) was
added. The mixture was extracted with dichloromethane (3ϫ
30 mL), the combined organic phase was dried with MgSO4, and
the solvent was removed. 4,4Ј-Diazido-2,2Ј-bipyridyl was then puri-
fied by column chromatography (silica gel, dichloromethane/Ac- room temperature. The organic phase was washed twice with water
1
OEt, 1:1) to yield a yellow solid (0.09 g, 95%). H NMR (CDCl3):
δ = 8.58 (d, J = 5.4 Hz, 2 H, 6-H), 8.14 (d, J = 2.2 Hz, 2 H, 3-H),
6.96 (dd, J = 5.4 and 2.2 Hz, 2 H, 5-H) ppm. 13C NMR (CDCl3):
δ = 157.3, 150.8, 150.3, 114.9, 111.8 ppm. MS (ESI): m/z = 261 [M
(30 mL) and once with brine (30 mL) and then dried with MgSO4.
The solvent was removed under vacuum, and the product was
recrystallized from dichloromethane and hexane to yield a white
1
solid (0.31 g, 81%). H NMR (CDCl3): δ = 8.91 (s, 1 H, Tz), 8.88
+ Na]+. HRMS: calcd for. C10H6N8Na [M + Na]+ 261.060765; [d, J = 2.1 Hz, 1 H, bpy py(tz)], 8.85 [d, J = 5.4 Hz, 1 H, bpy
found 261.060763. IR (ATR): ν = 2117 cm– 1
.
py(tz)], 8.72 (ddd, J = 4.8, 1.8 and 0.8 Hz, 1 H, tz-py), 8.65 (ddd,
J = 4.8, 1.7 and 0.8 Hz, 1 H, bpy py), 8.49 (dt, J = 8.0 and 0.8 Hz,
1 H, tz-py), 8.27 (dt, J = 8.0 and 0.9 Hz, 1 H, bpy py), 7.97 [dd, J
= 5.4 and 2.2 Hz, 1 H, bpy py(tz)], 7.87 (td, J = 7.8 and 1.7 Hz, 1
H, tz-py), 7.84 (td, J = 7.8 and 1.7 Hz, 1 H, bpy py), 7.38 (ddd, J
= 7.5, 4.8 and 1.2 Hz, 1 H, tz-py), 7.30 (ddd, J = 7.7, 4.8 and
1.2 Hz, 1 H, bpy py) ppm. 13C NMR (CDCl3): δ = 158.7, 154.8,
151.1, 149.7, 149.6, 149.56, 149.4, 144.1, 137.1, 137.0, 124.5, 123.4,
121.3, 120.6, 119.6, 113.8, 110.7 ppm. MS (ESI): m/z = 323 [M +
Na]+. HRMS: calcd. for C17H12N6Na [M + Na]+ 323.101566;
found 323.101593.
˜
4-(4-Phenyl-1,2,3-triazol-1-yl)-2,2Ј-bipyridyl (2a): 4-Azido-2,2Ј-bi-
pyridyl (0.5 g, 2.54 mmol) and phenylacetylene (0.39 g, 3.80 mmol)
were dissolved in THF (30 mL), and water was added (30 mL).
CuSO4 (1 m aqueous solution, 2.54 mL) was then added followed
by freshly prepared sodium ascorbate solution (1 m aqueous solu-
tion, 5.08 mL) dropwise. The solution was allowed to stir at room
temperature for 1 h. After removal of the THF under vacuum,
dichloromethane (30 mL) and conc. NH3 (15 mL) were added to
the solution. The solution was allowed to stir for a further 30 min
at room temperature to remove CuI. The organic phase was washed
twice with water (30 mL) and once with brine (30 mL) and then
dried with MgSO4. The solvent was removed under vacuum, and
the product was recrystallized from dichloromethane and hexane
[Ru(p-cymene)(1)Cl]PF6
(3):
[Ru(p-cymene)(Cl)2]2
(0.1 g,
0.16 mmol) and 1 (0.098 g, 0.5 mmol) were suspended in methanol
(30 mL) and stirred at room temperature for 12 h. The yellow solu-
tion was concentrated to 15 mL and treated with NaPF6 to yield a
yellow precipitate, which was collected by filtration and washed
with methanol and diethyl ether to yield the desired complex as
1
to yield a buff solid (0.58 g, 76%) H NMR (CDCl3): δ = 8.84 (d,
J = 5.3 Hz, 1 H, bpy 6-H), 8.75 (d, J = 2.1 Hz, 1 H, bpy 3-H), 8.72
(d, J = 4.5 Hz, 1 H, py), 8.50 (d, J = 8.0 Hz, 1 H, py), 8.48 (s, 1
H, Tz), 7.99 [dd, J = 5.3 & 2.1 Hz, 1 H, py(tz)], 7.94 (d, J = 7.7 Hz,
2 H, Ph), 7.87 (td, J = 7.7 and 1.6 Hz, py), 7.48 (t, J = 7.7 Hz, 2
H, Ph), 7.39 (m, 2 H, Ph and py) ppm. 13C NMR (CDCl3): δ =
158.5, 154.8, 151.1, 149.3, 149.0, 144.1, 137.1, 129.8, 129.0, 128.8,
126.0, 124.5, 121.4, 116.9, 113.9, 110.2 ppm. MS (ESI): m/z = 322
[M + Na]+. HRMS: calcd. for C18H13N5Na [M + Na]+ 322.106317;
found 322.106153.
1
yellow crystals (0.15 g, 76%). H NMR (CD3CN): δ = 9.34 (ddd,
J = 5.7, 1.3 and 0.7 Hz, 1 H, bpy H-6Ј), 9.15 (d, J = 6.3 Hz, 1 H,
bpy 6-H), 8.35 (d, J = 8.1 Hz, 1 H, bpy 3Ј-H), 8.19 (td, J = 8.0
and 1.4 Hz, 1 H, bpy 4Ј-H), 7.92 (d, J = 2.5 Hz, 1 H, bpy 3-H),
7.72 (ddd, J = 7.6, 5.7 and 1.4 Hz, 1 H, bpy 5Ј-H), 7.37 (dd, J =
6.3 and 2.5 Hz, bpy 5-H), 5.91 (t, J = 5.7 Hz, 2 H, Cym CH-CiPr),
5.71 (m, 2 H, Cym CH-CMe), 2.65 (sept, J = 7.0 Hz, iPr CH), 2.21
(s, 3 H, Cym Me), 1.04 (d, J = 7.0 Hz, 3 H, iPr CH3), 1.03 (d, J =
7.0 Hz, 3 H, iPr CH3) ppm. 13C NMR (CD3CN): δ = 159.9, 159.8,
156.6, 155.3, 154.1, 140.9, 129.0, 125.0, 118.8, 115.4, 106.1, 104.6,
87.4, 85.2, 31.9, 22.2, 19.0 ppm. MS (ESI): m/z = 468.1 [M –
4-(4-Ferrocenyl-1,2,3-triazol-1-yl)-2,2Ј-bipyridyl (2b): 4-Azido-2,2Ј-
bipyridyl (0.10 g, 0.51 mmol) and ethynylferrocene (0.16 g,
0.76 mmol) were dissolved in THF (15 mL), and water was added
(15 mL). CuSO4 (1 m aqueous solution, 0.51 mL) was added fol-
Eur. J. Inorg. Chem. 2013, 2571–2579
2576
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
FULL PAPER
PF6]+. HRMS: calcd. for C20H21ClN5Ru [M – PF6]+ 468.052349;
found 468.054448. IR (ATR): ν = 2124 cm– 1
solved in THF (30 mL), and water was added (30 mL). At 20 °C,
CuSO4 (1 m aqueous solution, 0.214 mL) was added followed by
freshly prepared sodium ascorbate solution (1 m aqueous solution,
0.428 mL) dropwise. The solution was allowed to stir at room tem-
perature for 12 h. After removal of the THF under vacuum, di-
chloromethane (30 mL) and conc. NH4OH (15 mL) were added to
the solution, which was allowed to stir for a further 30 min at room
temperature. The organic phase was washed twice with water
(30 mL) and once with brine (30 mL) and then dried with MgSO4.
The solvent was removed under vacuum, and the product was
recrystallized from acetonitrile and ether to yield an orange/red
solid. (0.10 g, 69%).
.
˜
[Ru(p-cymene)(1Ј)Cl]PF6
(3Ј):
[Ru(p-cymene)(Cl)2]2
(0.1 g,
0.16 mmol) and 1Ј (0.12 g, 0.5 mmol) were suspended in methanol
(30 mL) and stirred at room temperature for 12 h. The yellow solu-
tion was concentrated to 15 mL and treated with NaPF6 to yield a
yellow precipitate, which was collected by filtration and washed
with methanol and diethyl ether to yield the desired complex as
yellow crystals (0.14 g, 66%). 1H NMR (CD3CN): δ = 9.15 (d, J =
6.4 Hz, 2 H, bpy 6-H), 7.94 (d, J = 2.4 Hz, 2 H, bpy 3-H), 7.37
(dd, J = 6.4 and 2.4 Hz, 2 H, bpy 5-H), 5.90 (d, J = 6.2 Hz, 2 H,
Cym CH-CiPr), 5.69 (d, J = 6.2 Hz, 2 H, Cym CH-CMe), 2.65
(sept, J = 7.0 Hz, iPr CH), 2.21 (s, 3 H, Cym Me), 1.05 (d, J =
7.0 Hz, 3 H, iPr CH3) ppm. 13C NMR (CD3CN): δ = 157.0, 156.5,
154.3, 119.1, 115.7, 105.9, 104.6, 87.3, 85.0, 31.9, 22.3, 19.0 ppm.
1H NMR (CD3CN): δ = 9.44 (d, J = 6.2 Hz, 1 H, bpy 6Ј-H), 9.38
(d, J = H = 5.5 Hz, 1 H, bpy 6-H), 8.73 (br. s, 1 H, bpy 3-H), 8.64
(s, 1 H, Tz), 8.53 (d, J = 7.9 Hz, 1 H, bpy 3Ј-H), 8.27 (t, J = 7.9 Hz,
1 H, bpy 4Ј-H), 8.17 (d, J = 5.6 Hz, 1 H, bpy 5-H), 7.77 (t, J =
6.5 Hz, 1 H, bpy 5Ј-H), 5.98 (t, J = 5.6 Hz, 2 H, Cym CH-CiPr),
5.78 (d, J = 6.5 Hz, 2 H, Cym CH-CMe), 4.85 (s, 2 H, Fc-C5H4),
MS (ESI): m/z
C20H20ClN8Ru [M – PF6]+ 509.0537; found 509.0559. IR (ATR):
ν = 2125 cm– 1
= 509.1 [M –
PF6]+. HRMS: calcd. for
.
˜
[Ru(p-cymene)(2a)Cl]PF6 (4a). Route A: [Ru(p-cymene)(Cl)2]2 4.42 (s, 2 H, Fc-C5H4), 4.13 (s, 5 H, Cp), 2.70 (sept, J = 6.9 Hz,
(0.1 g, 0.16 mmol) and 2a (0.15 g, 0.5 mmol) were dissolved in
methanol (30 mL) and stirred at room temperature for 12 h. The
yellow solution was concentrated to 15 mL and treated with NaPF6
to yield a yellow precipitate, which was collected by filtration and
washed with methanol and diethyl ether to yield the desired com-
plex as yellow crystals (0.15 g, 66%).
iPr CH), 2.24 (s, 3 H, Cym Me), 1.07 (d, J = 6.9 Hz, iPr CH3),
1.07 (d, J = 6.9 Hz, iPr CH3) ppm. 13C NMR (CD3CN): δ = 157.9,
157.5, 156.8, 155.2, 149.9, 146.4, 141.1, 129.3, 125.4, 118.8, 117.6,
114.2, 106.5, 104.9, 87.6, 87.5, 85.5, 85.4, 70.8, 70.4, 68.0, 31.9,
22.3, 19.0 ppm. MS (ESI): m/z = 678.1 [M – PF6]+. HRMS: calcd.
for C32H31ClFeN5Ru [M – PF6]+ 678.065542; found 678.068143.
Route B: [(4-Azido-2,2Ј-bipyridyl)RuCl(p-cymene)]PF6 (0.1 g,
0.214 mmol) and phenylacetylene (0.033 g, 0.321 mmol) were dis-
solved in THF (30 mL), and water was added (30 mL). At 20 °C,
CuSO4 (1 m aqueous solution, 0.214 mL) was added followed by
freshly prepared sodium ascorbate solution (1 m aqueous solution,
0.428 mL) dropwise. The solution was allowed to stir at room tem-
perature for 12 h. After removal of the THF under vacuum, dichlo-
romethane (30 mL) and conc. NH4OH (15 mL) were added to the
solution, which was allowed to stir for a further 30 min at room
temperature. The organic phase was washed twice with water
(30 mL) and once with brine (30 mL) and then dried with MgSO4.
The solvent was removed under vacuum, and the product was
recrystallized from acetonitrile and ether to yield a yellow solid
(0.097 g, 80%).
[Ru(p-cymene)(2c)Cl]PF6 (4c): [(4-Azido-2,2Ј-bipyridyl)RuCl(p-
cymene)]PF6 (0.1 g, 0.214 mmol) and 2-ethynylpyridine (0.033 g,
0.321 mmol) were dissolved in THF (30 mL), and water was added
(30 mL). At 20 °C, CuSO4 (1 m aqueous solution, 0.214 mL) was
added followed by freshly prepared sodium ascorbate solution (1 m
aqueous solution, 0.428 mL) dropwise. The solution was allowed
to stir at room temperature for 12 h. After removal of the THF
under vacuum, dichloromethane (30 mL) and conc. NH4OH
(15 mL) were added, and the mixture was allowed to stir for a
further 12 h at room temperature. The organic phase was washed
twice with water (30 mL) and once with brine (30 mL) and then
dried with MgSO4. This was repeated, and the solvent was removed
under vacuum. The product was recrystallized from acetonitrile
and ether to yield an orange solid (0.057 g, 47%). 1H NMR
(CD3CN): δ = 9.45 (d, J = 6.4 Hz, 1 H, bpy 6-H), 9.36 (dd, J =
5.7 and 1.0 Hz, 1 H, bpy-H6Ј), 9.14 (s, 1 H, Tz), 8.74 (d, J = 1.9 Hz,
1 H, bpy-H3), 8.66 (s, 1 H, Py-H3), 8.50 (d, J = 7.6 Hz, 1 H, bpy-
H3Ј), 8.28–8.16 (m, 3 H, bpy-H4Ј, bpy-H5 and Py-H4), 7.91 (t, J
= 7.7 Hz, 1 H, Py-H5), 7.73 (td, J = 6.4 and 1.0 Hz, 1 H, bpy-
1H NMR (CD3CN): δ = 9.47 (d, J = 6.5 Hz, 1 H, bpy 6-H), 9.39
(d, J = 5.8 Hz, 1 H, bpy 6Ј-H), 8.99 (s, 1 H, Tz), 8.78 (d, J = 2.4 Hz,
1 H, bpy 3-H), 8.52 (d, J = 8.1 Hz, 1 H, bpy 3Ј-H), 8.27 (td, J =
7.9 and 1.3 Hz, 1 H, bpy 4Ј-H), 8.21 (dd, J = 6.3 and 2.4 Hz, 1 H,
bpy 5-H), 8.00 (m, 2 H, o-Ph), 7.78 (ddd, 7.6, 5.7 and 1.3 Hz, 1 H,
bpy 5Ј-H), 7.57 (t, J = 7.8 Hz, 2 H, m-Ph), 7.48 (tt, J = 7.4 and H5Ј), 7.39 (s, 1 H, Py-H6), 5.9 (t, J = 6.3 Hz, 2 H, Cym CH-CiPr),
1.2 Hz, 1 H, p-Ph), 5.98 (m, 2 H, Cym CH-CiPr), 5.78 (d, J = 5.76 (d, J = 6.3 Hz, 2 H, Cym CH-CMe), 2.68 (sept, J = 6.8 Hz, 1
6.3 Hz, 2 H, Cym CH-CMe), 2.71 (sept, J = 7.0 Hz, 1 H, iPr CH), H, iPr CH), 2.16 (s, 3 H, Cym CH3), 1.06 (d, J = 1.8 Hz, iPr CH3),
2.25 (s, 3 H, Cym CH3), 1.08 (d, J = 7 Hz, iPr CH3), 1.07 (d, J = 1.04 (d, J = 1.8 Hz, iPr CH3) ppm. 13C NMR (CD3CN): δ = 157.9,
7 Hz, iPr CH3) ppm. 13C NMR (CD3CN): δ = 157.9, 157.5, 156.7, 157.6, 156.8, 155.0, 151.1, 150.9, 150.0, 146.3, 141.1, 138.3, 129.3,
155.0, 149.9, 146.3, 141.0, 130.5, 130.2, 130.0, 129.2, 126.7, 125.3,
120.1, 117.7, 114.4, 106.5, 104.7, 87.5, 87.4, 85.5, 85.4, 31.8, 22.1,
18.9 ppm. MS (ESI): m/z = 570.1 [M – PF6]+. HRMS: calcd. for
C28H27ClN5 [M – PF6]+ Ru 570.099300; found 570.099993.
125.5, 124.9, 122.1, 121.3, 118.1, 114.6, 106.5, 104.8, 87.6, 87.5,
85.5, 85.4, 31.9, 22.2, 19.0 ppm. MS (ESI): m/z = 571.1 [M –
PF6]+. HRMS: calcd. for C27H26ClN6Ru [M – PF6]+ 571.094548;
found 571.095033.
[Ru(p-cymene)(2b)Cl]PF6 (4b). Route A: [Ru(p-cymene)(Cl)2]2
(0.1 g, 0.16 mmol) and 2b (0.20 g, 0.50 mmol) were dissolved in
methanol (30 mL) and stirred at room temperature for 12 h. The
yellow solution was concentrated to 15 mL and treated with NaPF6
to yield an orange precipitate, which was collected by filtration and
washed with methanol and diethyl ether to yield the desired com-
plex as an orange/red solid (0.21 g, 79%).
[{Ru(p-cymene)Cl}2(2c)][PF6]2 (5): [RuCl2(p-cymene)]2 (0.313 g,
0.5 mmol) and 1-pyridyl-4-(2,2Ј-bipyridyl)-1,2,3-triazole (0.150 g,
0.5 mmol) were reacted in ethanol (50 mL) for 48 h. The solution
was evaporated to dryness to afford an orange-brown solid. The
orange-brown solid was dissolved in acetonitrile (3 mL), and a
solution of AgPF6 (0.06 g, 0.22 mmol) in acetonitrile (2 mL) was
added dropwise with stirring. The reaction mixture was stirred for
a further 10 min and filtered through Celite, and the solvents were
evaporated to dryness to yield an orange solid (0.22 g, 88%). 1H
Route B: [(4-Azido-2,2Ј-bipyridyl)RuCl(p-cymene)]PF6 (0.1 g,
0.214 mmol) and ethynylferrocene (0.067 g, 0.321 mmol) were dis-
Eur. J. Inorg. Chem. 2013, 2571–2579
2577
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
FULL PAPER
NMR (CD3CN): δ = 9.58 (dd, J = 5.2 and 1.6 Hz, 1 H, bpy 6-H),
9.44 (d, J = 9.6 Hz, 1 H, Tz), 9.39 (dt, J = 5.6 and 1.3 Hz, 1 H,
bpy 6Ј-H), 9.33 (d, J = 5.4 Hz, 1 H, Py 6-H), 8.34 (dd, J = 13.2
and 2.3 Hz, 1 H, bpy 3-H), 8.56 (t, J = 7.7 Hz, bpy 3Ј-H), 8.25 (m,
3 H, bpy 4Ј-H, bpy 5-H and Py 4-H), 8.08 (d, J = 7.9 Hz, 1 H, Py
3-H), 7.80 (m, 1 H, bpy 5Ј-H), 7.69 (t, J = 6.6 Hz, 1 H, Py 5-H),
6.09 (d, 6.0 Hz, 1 H, cymene pytz), 6.00 (m, 3 H, cymene bpy),
5.89 (dd, J = 6.0 and 2.5 Hz, 1 H, cymene bpy), 5.81 (m, 3 H,
cymene pytz), 2.78 (sept, J = 6.4 Hz, 1 H, iPr CH pytz), 2.69 (m,
1 H, iPr CH bpy), 2.23 (d, J = 3.6 Hz, 3 H, Cym Me bpy), 2.21 (s,
3 H, Cym Me pytz), 1.16 (dd, J = 6.4 and 1.6 Hz, 3 H, iPr CH3
pytz), 1.11 (d, 6.8 Hz, 3 H, iPr CH3 pytz), 1.07 (d, J = 7.0 Hz, 6
H, iPr CH3 bpy) ppm. 13C NMR (CD3CN): δ = 158.4, 158.0, 156.9,
156.8, 154.7, 149.0, 148.0, 148.3, 145.3, 145.2, 141.7, 141.3, 141.2,
129.7, 128.0, 125.7, 124.4, 124.3, 124.0, 118.6, 118.5, 118.3,
115.3,115.2, 107.2, 107.2, 107.0, 106.9, 105.1, 105.1, 104.0, 103.9,
87.9, 87.8, 87.6, 87.2, 87.2, 86.2, 85.8, 85.7, 85.7, 85.6, 85.6, 84.8,
32.0, 31.9, 22.5, 22.3, 22.3, 22.0, 22.0, 19.0, 18.9 ppm. MS (ESI):
m/z = 421 [M – 2PF6]2+. HRMS: calcd. for C37H40Cl2N6Ru2 [M –
2PF6]2+ 421.038376; found 421.040178.
ppm. 13C NMR (CD3CN): δ = 157.9, 157.8, 156.7, 155.4, 147.7,
147.7, 146.7, 141.1, 129.2, 126.0, 123.9, 114.9, 106.5, 104.8, 87.6,
87.5, 85.6, 85.5, 64.1, 31.9, 22.3, 19.0 ppm. MS (ESI): m/z = 515.1
[M – 2PF6]2+. HRMS: calcd. for C46H48Cl2N10ORu2 [M – 2PF6]2+
515.0733; found 515.0781.
Supporting Information (see footnote on the first page of this arti-
cle): Atomic xyz coordinates for the molecular structure of 3Ј and
NMR spectra of ligands and complexes.
Acknowledgments
The authors thank the University of Huddersfield for supporting
this research. Prof. Craig R. Rice is thanked for collecting the X-
ray crystallographic data.
[1] O. S. Wenger, Coord. Chem. Rev. 2009, 253, 1439–1457.
[2] E. C. Constable, Coord. Chem. Rev. 2008, 252, 842–855.
[3] V. Balzani, G. Bergamini, F. Marchioni, P. Ceroni, Coord.
Chem. Rev. 2006, 250, 12541266.
[4] E. C. Constable, Chem. Commun. 1997, 1073–1080.
[5] M. Meldal, C. W. Tornoe, Chem. Rev. 2008, 108, 2952–3015.
[(p-cymene)RuCl(pytz)]PF6 (6): [RuCl2(p-cymene)]2 (0.313 g,
0.5 mmol) and 1-pyridyl-4-benzyl-1,2,3-triazole (0.223 g, 1.0 mmol) [6] H. C. Kolb, M. G. Finn, K. B. Sharpless, Angew. Chem. 2001,
113, 2056; Angew. Chem. Int. Ed. 2001, 40, 2004–2021.
[7] D. Fournier, R. Hoogenboom, U. S. Schubert, Chem. Soc. Rev.
2007, 36, 1369–1380.
[8] J. E. Moses, A. D. Moorhouse, Chem. Soc. Rev. 2007, 36, 1249–
1262.
[9] G. Franc, A. K. Kakkar, Chem. Soc. Rev. 2010, 39, 1536–1544.
[10] J. A. Prescher, C. R. Bertozzi, Nature Chem. Biol. 2005, 1, 13–
21.
were reacted in ethanol (50 mL) for 48 h. The solution was evapo-
rated to dryness to afford an orange-brown solid. The orange-
brown solid was dissolved in acetonitrile (3 mL), and a solution
of AgPF6 (0.143 g, 0.564 mmol) in acetonitrile (2 mL) was added
dropwise with stirring. The reaction mixture was stirred for a fur-
ther 10 min and filtered through Celite, and the solvents were evap-
1
orated to dryness to yield an orange solid (0.34 g, 93%). H NMR
(CD3CN): δ = 9.23 (d, J = 5.4 Hz, 1 H, Py 6-H), 8.56 (s, 1 H, Tz),
8.09 (td, J = 7.9 and 1.3 Hz, 1 H, Py 4-H), 7.92 (d, J = 7.9 Hz, 1
H, Py 3-H), 7.57 (td, J = 6.9 and 1.3, 1 H, Py 5-H), 7.46 (m, 5 H,
benzyl), 6.00–5.60 (m, 6 H, Cym CH-CiPr, Cym CH-Me and CH2-
benzyl), 2.63 (sept, J = 6.9 Hz, iPr CH), 2.16 (s, 3 H, Cym Me),
1.09 (d, J = 6.9 Hz, iPr CH3), 0.94 (d, J = 6.9 Hz, iPr CH3) ppm.
13C NMR (CD3CN): δ = 156.3, 149.1, 147.4, 141.1, 134.8, 130.2,
129.6, 127.0, 125.8, 123.5, 106.1, 103.1, 86.5, 85.2, 85.1, 84.5, 56.9,
31.7, 22.4, 21.6, 18.7 ppm. MS (ESI): m/z = 507.1 [M – PF6]+.
HRMS: calcd. for C24H26ClN4Ru [M – PF6]+ 507.088400; found
507.090438.
[11] A. H. El-Sagheer, T. Brown, Chem. Soc. Rev. 2010, 39, 1388–
1405.
[12] S. Bedeche, J.-C. Daran, J. Ruiz, D. Astruc, Inorg. Chem. 2008,
47, 4903–4908.
[13] B. Beyer, C. Ulbricht, D. Escudero, C. Friebe, A. Winter, L.
Gonzalez, U. S. Schubert, Organometallics 2009, 28, 5478–
5488.
[14] I. Bratsos, D. Urankar, E. Zangrando, P. Genova-Kalou, J.
Kosmrlj, E. Alessio, I. Turel, Dalton Trans. 2011, 40, 5188–
5199.
[15] M. Felici, P. Contreras-Carballada, Y. Vida, J. M. M. Smits,
R. J. M. Nolte, L. De Cola, R. M. Williams, M. C. Feiters,
Chem. Eur. J. 2009, 15, 13124–13134.
[[Ru(p-cymene)Cl]2(di{[1-(2,2Ј-bipyrid-4-yl)triazol-4-yl]methyl}-
ether)][PF6]2 (7): [(4-Azido-2,2Ј-bipyridyl)RuCl(p-cymene)] (0.1 g,
0.214 mmol) and dipropargyl ether (0.012 g, 0.130 mmol) were dis-
solved in THF (30 mL), and water was added (30 mL). At 20 °C,
CuSO4 (1 m aqueous solution, 0.214 mL) was added followed by
freshly prepared sodium ascorbate solution (1 m aqueous solution,
0.428 mL) dropwise. The solution was allowed to stir at room tem-
perature for 24 h. After removal of the THF under vacuum, di-
chloromethane (30 mL) and conc. NH4OH (15 mL) were added to
the solution, which was allowed to stir for a further 2 h at room
temperature. The organic phase was washed twice with water
(30 mL) and once with brine (30 mL) and then dried with MgSO4.
The solvent was removed under vacuum, and the product was
recrystallized from acetonitrile and ether to yield a red solid
(0.084 g, 60%). 1H NMR (CD3CN): δ = 9.47 (dd, J = 6.3 and
1.3 Hz, 2 H, bpy 6-H), 9.39 (d, J = 5.7 Hz, 2 H, bpy 6Ј-H), 9.30
(d, J = 5.9, 2 H, Tz), 9.14 (dd, J = 2.2 and 7.2 Hz, 2 H, bpy 3-H),
8.90 (t, J = 8.3 Hz, 2 H, bpy 3Ј-H), 8.37 (dt, J = 6.3 and 2.2 Hz, 2
H, bpy 5-H), 8.21 (tt, J = 7.7 and 1.3 Hz, 2 H, bpy 4Ј-H), 7.76 (tt,
J = 6.6 and 1.3 Hz, 2 H, bpy 4Ј-H), 5.99 (t, J = 7.4 Hz, 4 H, Cym
CH-CiPr), 5.79 (d, J = 6.5 Hz, 4 H, Cym CH-CMe), 4.86 (s, 4 H,
Tz-CH2-O), 2.70 (sept, J = 6.8 Hz, 2 H, iPr CH), 2.23 (s, 6 H, Cym
Me), 1.07 (d, J = 2.9 Hz, iPr CH3), 1.06 (d, J = 2.9 Hz, iPr CH3)
[16] O. Fleischel, N. Wu, A. Petitjean, Chem. Commun. 2010, 46,
8454–8456.
[17] G. Guisado-Barrios, J. Bouffard, B. Donnadieu, G. Bertrand,
Organometallics 2011, 30, 6017–2021.
[18] B. Happ, D. Escudero, M. D. Hager, C. Friebe, A. Winter, H.
Goerls, E. Altuntas, L. Gonzalez, U. S. Schubert, J. Org. Chem.
2010, 75, 4025–4038.
[19] B. Happ, C. Friebe, A. Winter, M. D. Hager, R. Hoogenboom,
U. S. Schubert, Chem. Asian J. 2009, 4, 154–163.
[20] S. Ladouceur, D. Fortin, E. Zysman-Colman, Inorg. Chem.
2011, 50, 11514–11526.
[21] Y. Li, J. C. Huffman, A. H. Flood, Chem. Commun. 2007,
2692–2694.
[22] S. Liu, P. Muller, M. K. Takase, T. M. Swager, Inorg. Chem.
2011, 50, 7598–7609.
[23] P. Mathew, A. Neels, M. Albrecht, J. Am. Chem. Soc. 2008,
130, 13534–13535.
[24] U. Monkowius, S. Ritter, B. Konig, M. Zabel, H. Yersin, Eur.
J. Inorg. Chem. 2007, 4597–4606.
[25] M. Mydlak, C. Bizzarri, D. Hartmann, W. Sarfet, G. Schmid,
L. De Cola, Adv. Funct. Mater. 2010, 20, 1812–1820.
[26] M. Obata, A. Kitamura, A. Mori, C. Kameyama, J. A. Cza-
plewska, R. Tanaka, I. Kinoshita, T. Kusumoto, H. Hashim-
oto, M. Harada, Y. Mikata, T. Funabiki, S. Yano, Dalton
Trans. 2008, 3292–3300.
Eur. J. Inorg. Chem. 2013, 2571–2579
2578
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
FULL PAPER
[27] E. Orselli, R. Q. Albuquerque, P. M. Fransen, R. Frohlich,
H. M. Janssen, L. De Cola, J. Mater. Chem. 2008, 18, 4579–
4590.
[40] J. D. Crowley, D. A. McMorran, Top. Heterocycl. Chem. 2012,
28, 31–83.
[41] G.-L. Xu, T. Ren, Organometallics 2005, 24, 2564–2566.
[28] B. Schulze, C. Friebe, M. D. Hager, A. Winter, R. Hoogen- [42] W.-Z. Chen, T. Ren, Organometallics 2005, 24, 2660–2669.
boom, H. Goerls, U. S. Schubert, Dalton Trans. 2009, 787–794.
[29] E. M. Schuster, M. Botoshansky, M. Gandelman, Organome-
tallics 2009, 28, 7001–7005.
[30] D. Schweinfurth, S. Strobel, B. Sarkar, Inorg. Chim. Acta 2011,
374, 253–260.
[31] I. Stengel, A. Mishra, N. Pootrakulchote, S.-J. Moon, S. M.
Zakeeruddin, M. Graetzel, P. Baeuerle, J. Mater. Chem. 2011,
21, 3726–3734.
[43] B. Baeza, L. Casarrubios, P. Ramirez-Lopez, M. Gomez-Gal-
lego, M. A. Sierra, Organometallics 2009, 28, 956–959.
[44] A. Chakraborty, S. Dey, S. Sawoo, N. N. Adarsh, A. Sarkar,
Organometallics 2010, 29, 6619–6622.
[45] E. C. Constable, C. E. Housecroft, M. Neuberger, P. Rosel,
Chem. Commun. 2010, 46, 1628–1630.
[46] R. A. Fallahpour, M. Neuburger, Helv. Chim. Acta 2001, 84,
715–721.
[32] H. Struthers, T. L. Mindt, R. Schibli, Dalton Trans. 2010, 39,
[47] R. A. Fallahpour, M. Neuburger, M. Zehnder, Synthesis Stutt-
gart 1999, 1051–1055.
675–696.
[33] Y. Tulchinsky, M. A. Iron, M. Botoshansky, M. Gandelman,
Nature Chem. 2011, 3, 525–531.
[34] L. Wang, W.-W. Yang, R.-H. Zheng, Q. Shi, Y.-W. Zhong, J.
Yao, Inorg. Chem. 2011, 50, 7074–7079.
[35] S. Zanarini, M. Felici, G. Valenti, M. Maracaccio, L. Prodi,
S. Bonacchi, P. Contreras-Carballada, R. M. Williams, M. C.
Feiters, R. J. M. Nolte, L. De Cola, F. Paolucci, Chem. Eur. J.
2011, 17, 4640–4647.
[48] A. Winter, A. Wild, R. Hoogenboom, M. W. M. Fijten, M. D.
Hager, R.-A. Fallahpour, U. S. Schubert, Synthesis 2009, 1506–
1512.
[49] A. Baron, C. Herrero, A. Quaranta, M.-F. Charlot, W. Leibl,
B. Vauzeilles, A. Aukauloo, Chem. Commun. 2011, 47, 11011–
11013.
[50] K. P. Chitre, E. Guillen, A. S. Yoon, E. Galoppini, Eur. J. In-
org. Chem. 2012, 5461–5464.
[36] R. Lalrempuia, N. D. McDaniel, H. Muller-Bunz, S. Bernhard,
M. Albrecht, Angew. Chem. 2010, 122, 9959; Angew. Chem. Int.
Ed. 2010, 49, 9765–9768.
[37] J. D. Crowley, P. H. Bandeen, Dalton Trans. 2010, 39, 612–623.
[38] J. D. Crowley, P. H. Bandeen, L. R. Hanton, Polyhedron 2010,
29, 70–83.
[51] E. C. Constable, C. E. Housecroft, J. R. Price, L.
Schweighauser, J. A. Zampese, Inorg. Chem. Commun. 2010,
13, 495–497.
[52] R. A. Fallahpour, Helv. Chim. Acta 2000, 83, 384–393.
[53] M. A. Bennett, A. K. Smith, J. Chem. Soc., Dalton Trans. 1974,
233–241.
[39] M. L. Gower, J. D. Crowley, Dalton Trans. 2010, 39, 2371–
Received: November 22, 2012
Published Online: March 8, 2013
2378.
Eur. J. Inorg. Chem. 2013, 2571–2579
2579
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim