Synthesis, characterisation and ligand properties of novel Bi-1,2,3-triazole ligands

Article abstract of DOI:10.1002/ejic.200700479

Three 1,1′-disubstituted 4,4′-bi-1H-1,2,3-triazols [R-bta; R = Bn (1), Ph (2), CH₂COOH (3)] have been synthesised as bidentate, nitrogen-based ligands by a Cu^I-catalysed "click" reaction between 1,3-butadiyne and organic azides. Thei

Full text of DOI:10.1002/ejic.200700479

FULL PAPER
DOI: 10.1002/ejic.200700479
Synthesis, Characterisation and Ligand Properties of Novel
Bi-1,2,3-triazole Ligands
Uwe Monkowius,*[a] Stefan Ritter,[b] Burkhard König,*[b] Manfred Zabel,[b] and
Hartmut Yersin[c]
Keywords: N ligands / Ligand design / Nitrogen heterocycles / Click reaction / 1,2,3-Triazole
Three 1,1Ј-disubstituted 4,4Ј-bi-1H-1,2,3-triazols [R-bta; R =
Bn (1), Ph (2), CH2COOH (3)] have been synthesised as bi-
dentate, nitrogen-based ligands by a CuI-catalysed “click”
reaction between 1,3-butadiyne and organic azides. Their li-
gand properties were investigated by preparation of the com-
plexes [RuII(R-bta)3]Cl2 [R = Bn (4), Ph (5), CH2COOH (6)],
[(Bn-bta)CuI(DPEPhos)] (7) [DPEPhos = bis{2-(diphenylphos-
phanyl)phenyl} ether] and [(Bn-bta)ReI(CO)3Cl] (8) following
standard reaction procedures. All compounds were analysed
by elemental analysis, mass spectrometry and NMR, IR, UV/
ray crystallography. In all complexes the Bn-bta acts as a bi-
dentate ligand with structural features comparable to the
analogous 2,2Ј-bipyridine complexes. In their electronic ab-
sorption spectra the RuII and ReI complexes exhibit a lowest
energy band at around 300 nm, which is substantially higher
in energy than in analogous complexes with bpy ligands. All
R-bta ligands yield complexes that are not luminescent in
solution or in the solid state, which makes these ligands par-
ticularly suited for use as spectator ligands.
Vis and luminescence spectroscopy. In addition, the molecu- (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
lar structures of 1–4, 7, and 8 have been determined by X-
Germany, 2007)
due to the rapid development of OLED (organic light emit-
ting device) technology. It has been shown that the emission
energy increases with decreasing size of the chromophoric
π-system, and this strategy has been successfully applied by
Thompson et al. in the case of cyclometallated IrIII com-
plexes, where replacement of the pyridine moiety by the
five-membered ring of a pyrazolyl group led to a hypso-
chromic shift of the emission wavelength.[9] Chelating ligands
with high energy electronic states are also useful as auxil-
iary, ancillary, spectator or innocent ligands in light-emit-
ting complexes.[10] De Cola et al. recently reported a blue
light emitting heteroleptic IrIII complex (λmax = 461 nm),
where the anionic 1,2,4-triazolyl ligand (Figure 1) does not
participate directly in the electronic transition.[11–13]
Introduction
A large number of transition metal complexes based on
the 2,2Ј-bipyridine (bpy) ligand and its derivatives have
been investigated in different fields of chemistry due to their
high stability and remarkable (electro)chemical and photo-
physical properties. More than 4200 entries were found in
the Cambridge Structural Database when searching for
complexes with byp (February 2007). There have been many
reports about the application of these metal complexes in
opto-electronic devices, as redox- and photo-catalysts, as
building blocks of supramolecular structures and for medi-
cal and analytical purposes.[1–4] Prominent examples are
[Ru(bpy)3]2+ and related octahedral d6 transition metal
complexes, which are frequently employed in studies that
take advantage of the properties of their excited state, such
as in photochemistry, chemoluminescence, electro-chemolu-
minescence and electron-transfer chemistry.[5–8]
New chromophoric ligands that are capable of generating
emissions in the blue region of the spectrum are in demand
[a] Institut für Anorganische Chemie, Johannes Kepler Universität
Linz,
4040 Linz, Austria
E-Mail: Uwe.Monkowius@jku.at
[b] Institut für Organische Chemie, Universität Regensburg,
93040 Regensburg, Germany
E-Mail: Burkhard.Koenig@chemie.uni-regensburg.de
[c] Institut für Physikalische Chemie, Universität Regensburg,
93040 Regensburg, Germany
Figure 1. Bpy and triazolyl-py, R-bta and R,RЈ-bta ligands.
1,1Ј-R2-4,4Ј-Bi(1,2,3-triazole) ligands (R-bta, R = or-
ganic group) seem to be promising alternatives to bipyr-
Supporting information for this article is available on the
WWW under http://www.eurjic.org or from the author.
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FULL PAPER
Scheme 1. Synthesis of the bitriazoles 1–3.
idine ligands in transition metal complexes (Figure 1). In 260 nm (Figure 11, Figures S3 and S4 in the Supporting In-
addition, functionalisation with a wide range of different formation). Compound 3 shows a very weak emission sig-
substituents is possible using the “click chemistry” ap- nal at 414 nm (λex = 267 nm) in the luminescence spectrum.
proach for the preparation of novel R-bta ligands.[14] Com-
pared to bpy, where substitution with certain organic
groups is usually cumbersome,[4,15] this may facilitate ligand
preparation significantly. CuAAC (copper-catalysed azide-
Structural Studies
All free ligands were structurally characterised by single-
crystal X-ray experiments. Ligand 1 crystallises in two dif-
ferent modifications, namely prisms (monoclinic space
group P21/c, with two molecules in the unit cell) and need-
les (monoclinic space group Cc, with four molecules in the
unit cell). Whereas the prisms crystallise as the more stable
form from most organic solvents used (e.g. CH2Cl2, CHCl3,
MeCN), needles are obtained as the major fraction only
by slow crystallisation from methanol. Because each of the
equivalent molecules in crystals of the first modification of
1 has an inversion centre, the asymmetric unit contains only
one half of the formula unit (Figure 2). The individual
molecules in the latter modification show no crystallo-
graphically imposed symmetry, but they approach closely
the symmetry of the molecules in the prismatic crystal (Fig-
ure 3).
alkyne cycloaddition) has been used recently to synthesise
1,4-disubstituted 1,2,3-triazole ligands,[16] and the oxidative
coupling products R,RЈ-bta (Figure 1) have been observed
as major products under basic conditions in the CuAAC.[17]
Complexes of RuII, ReI and CuI have been synthesised
to evaluate the ligand properties of R-bta and the spectro-
scopic behaviour of these ligands and complexes investi-
gated by UV/Vis and luminescence spectroscopy.
Results and Discussion
Synthesis of Triazole Ligands
The desired R-bta ligands 1–3 were synthesised by a CuI-
catalysed cycloaddition between 1,3-butadiyne and the or-
ganic azides (benzyl azide, phenyl azide[14] and β-azidoace-
tic acid). The 1,3-butadiyne was freshly prepared from 1,4-
dichlorobutyne[18] and treated immediately with the azide
compound in basic acetonitrile solution in the presence of
a catalytic amount of copper iodide (Scheme 1). Workup
with aqueous H2O2 (3%) and saturated aqueous EDTA was
necessary to remove the CuI salt as it could form a complex
with the synthesised R-bta ligands. Compounds 1–3 were
obtained in acceptable yields as colourless powders after
purification. All compounds are sparingly soluble in most
organic solvents and insoluble in water.
Figure 2. ORTEP drawing of the molecular structure of compound
1 (prismatic crystals) with 50% probability ellipsoids. Selected
bond lengths [Å], angles [°] and torsion angles [°]: N1–N2
1.3476(15), N2–N3 1.3195(15), N3–C4 1.3643(17), N1–C5
1.3522(15), C4–C4Ј 1.4666(16), C4–C5 1.3764(17); N1–N2–N3
107.26(10), N2–N3–C4 108.71(10), N3–C4–C5 108.54(10), C4–C5–
N1 104.45(11), N2–N1–C5 111.05(10), C4Ј–C4–C5 129.85(11);
N3–C4–C4Ј–N3Ј 180.00(11).
Spectroscopic Characterisation
The spectroscopic properties of compounds 1–3 were in-
vestigated by UV/Vis and luminescence spectroscopy. The Compound 2 crystallises in the triclinic space group P1
Compounds 2 and 3 were obtained as colourless needles.
¯
compounds absorb in the UV region between 220 and with three molecules in the unit cell and 1.5 formula units
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Synthesis and Ligand Properties of Bi-1,2,3-triazole Ligands
Figure 3. Molecular structure of compound 1 (needles). Selected
bond lengths [Å], angles [°] and torsion angles [°]: N1–N2 1.344(4),
N2–N3 1.328(4), N3–C4 1.368(4), C4–C5 1.374(4), N1–C5
1.356(4), N4–N5 1.353(4), N5–N6 1.331(4), N6–C7 1.371(4), C7–
C8 1.372(4), C8–N4 1.354(4), C4–C7 1.463(3); N2–N1–C5
111.6(2), N1–N2–N3 107.0(2), N2–N3–C4 108.4(3), N3–C4–C5
108.9(3), C4–C5–N1 104.1(3), C5–C4–C7 130.6(3), N5–N4–C8
11.6(2), N4–N5–N6 106.7(2), N5–N6–N7 108.4(2), N6–C7–C8
109.0(2), C7–C8–N4 104.3(2), C4–C7–C8 129.2(3); N3–C4–C7–N6
174.9(3).
Figure 5. Molecular structure of compound 3. Selected bond
lengths [Å], angles [°] and torsion angles [°]: N1–N2 1.339(4), N2–
N3 1.328(5), N3–C4 1.359(5), N1–C5 1.345(5), C4–C4Ј 1.446(5),
C4–C5 1.377(5); N1–N2–N3 106.1(3), N2–N3–C4 109.5(3), N3–
C4–C5 107.9(3), C4–C5–N1 104.6(3), N2–N1–C5 112.0(3), C4Ј–
C4–C5 130.0(3); N3–C4–C4Ј–N3Ј 180.0(4).
per asymmetric unit. This means that there are two inde-
pendent molecules present, one of which is centrosymmetric
and the other roughly C2-symmetric (Figure 4). Crystals of
compound 3 are monoclinic (space group P21/c with two
molecules in the unit cell). Again, the molecules in crystals
of compound 3 are centrosymmetric and the asymmetric
unit consists of one half of the formula unit (Figure 5). The
carboxylate proton exhibits an intermolecular hydrogen
bond with the N3 atom of a neighbouring molecule to form
helices [d(O1–H) 0.80(6), d(H–N3) 1.88(6), d(O1–N3)
2.670(4) Å; Є(O1–H–N3) 171(4)°; Figure 6]. Each discrete
helical subunit is connected to two others by the second
carboxylate group of the molecule to yield a layered struc-
ture of interconnected helices (Figure S1).
Figure 6. Excerpt from a cell plot of the crystalline phase of com-
pound 3 depicting the helix formed by the intermolecular hydrogen
bonds (dotted lines) between the carboxylate protons and the N3
atoms of the neighbouring molecules. Only the participating H
atoms are shown for clarity.
Figure 4. Structure of the two independent molecules in crystals of
compound 2. Selected bond lengths [Å], angles [°] and torsion
angles [°]: C8–C8Ј 1.452(2), N1–N2 1.357(3), N2–N3 1.310(3), N3–
C8 1.365(4), C7–C8 1.372(4), N4–N5 1.358(3), N5–N6 1.312(3),
N6–C16 1.368(4), C15–C16 1.372(4), C16–C17 1.449(4), C17–C18
1.374(4), C17–N7 1.368(4), N7–N8 1.310(3), N8–N9 1.362(3); N2–
N1–C7 110.5(2), N1–N2–N3 107.4(2), N2–N3–C8 108.7(2), N1–
C7–C8 105.1(2), N3–C8–C7 108.3(2), C7–C8–C8Ј 129.6(2), N5–
N4–C15 110.6(2), N4–N5–N6 107.3(2), N5–N6–C16 108.9(2), N4–
C15–C16 105.0(2), N6–C16–C15 108.3(2), N8–N7–C17 108.9(2),
N7–N8–N9 107.3(2), N8–N9–C18 110.4(2), N7–C17–C18 108.1(2),
C15–C16–C17 130.5(2), C16–C17–C18 129.7(2), C17–C18–N9
105.3(2); N3–C8–C8Ј–N3Ј 180.0(2), N6–C16–C17–N7 173.3(2).
Synthesis of Complexes
The synthesis of homoleptic RuII complexes of ligands
1–3 was carried out with RuCl3·4H2O in boiling ethylene
glycol solution. Precipitation of complexes 4–6 was pro-
voked by addition of ethanol or diethyl ether (Scheme 2).
The synthesis of a heteroleptic CuI complex (7) was per-
formed with ligand 1, bis[2-(diphenylphosphanyl)phenyl]
ether (DPEPhos) and [CuI(NCMe)4]PF6 (Scheme 3). The
DPEPhos ligand was chosen as related heteroleptic CuI
complexes with a 1,10-phenanthroline (phen) ligand show
high quantum yields.[21] The colourless crystals of this com-
The bitriazole units of molecules 1–3 are planar with an plex are only modestly soluble in polar organic solvents.
(E)-configuration of the 3,3Ј-N atoms. This configuration is Complex 7 is perfectly stable in solution and the solid state
also found in all solid-state structures of the free ligand in air at room temperature; no oxidation to CuII occurs.
2,2Ј-bipyridine.[19] All bond lengths and angles of the tri-
The heteroleptic carbonylrhenium(I) complex 8 was ob-
azole moiety lie in a very narrow range and are comparable tained from ligand 1 and [ReI(CO)5]Cl, after reaction in tol-
to those of previously published structures of 1,2,3-triazole uene and recrystallisation from MeCN/Et2O, as colourless
compounds.[20] The C–C bonds between the triazole groups crystals in almost quantitative yield (Scheme 4). This com-
have lengths of between 1.449 and 1.466 Å and are there- plex is modestly soluble in hot MeCN and, as is the case
fore shorter than the analogous bond in 2,2Ј-bipyridine for its bpy and phen analogs, it is stable in solution and the
[1.4881(13) Å] (Table 1).[19]
solid state in air.
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U. Monkowius, S. Ritter, B. König, M. Zabel, H. Yersin
FULL PAPER
Scheme 2. Synthesis of the homoleptic complexes 4–6.
Scheme 3. Synthesis of heteroleptic copper(I) complex 7.
The crystals of 7 obtained upon cooling of a dichloro-
¯
methane solution to –35 °C are triclinic (space group P1
with four molecules in the unit cell). The asymmetric unit
contains two independent complexes with both copper
atoms coordinated by 1 and DPEPhos in a distorted tetra-
hedral environment (Figures 8 and 9). There are no sub van
der Waals contacts between the oxygen of the phosphane
ligands and the copper centres. Both cations differ in their
geometrical parameters, with one benzyl group being disor-
dered over two positions in the cation containing Cu2 (oc-
cupation 55:45). Furthermore, the bta ligand deviates sig-
nificantly from planarity in the case of the cation contain-
ing Cu1 [Cu1: Є(N3–C45–C46–N4) 14.9(8)°; Cu2: Є(N10–
C106–C107–N9) 3.0(6)°]. There is a high degree of asym-
metry in the bitriazole coordination [Cu1–N3 2.118(4),
Cu1–N4 2.201(5), Cu2–N9 2.233(5), Cu2–N10 2.075(6) Å],
as was also found, although less pronounced, for bpy in the
crystal structure of the complex [(bpy)Cu(PPh3)2]ClO4.[23]
The bite angle of bpy in the latter complex and of the
bi-triazoles in 7 are comparable [78.53(18)/78.7(2)° vs.
79.6(4)°].[23] The asymmetric coordination of the copper
atoms in the crystal structure of 7 arises due to the steric
restraints of the bta and DPEPhos ligand, and the differ-
ences between the two cations are caused by the disordered
benzyl group and packing forces.
Scheme 4. Synthesis of heteroleptic rhenium(I) complex 8.
Structural Studies
Recrystallisation from ethylene glycol/ethanol or MeCN/
Et2O yielded complexes 4–6 as light yellow crystals, al-
though only the crystals of complex 4 were of sufficient,
though still low, quality for an X-ray structure refinement
(Figure 7). The quality of the structural data is less accurate
because crystals of 4 contain an unspecified number and
type of solvent molecules (Figure S2 in the Supporting In-
formation). Complex 4 crystallises in the monoclinic space
group P21/a with four molecules in the unit cell. The RuII
atom shows a distorted octahedral coordination geometry
with both the Λ and ∆ enantiomers present in the unit cell. The
benzyl substituents have a random orientation and do not
approach a symmetrical pattern. The average Ru–N distances
of the cations in 4 [d(Ru–N) 2.05(3) Å] and [Ru(bpy)3]2+
[d(Ru–N) 2.056(2) Å] are roughly the same within experi-
mental error. The average bite angles of the bpy ligand in
Crystals of 8 were obtained from MeCN/Et2O. The com-
[Ru(bpy)3]2+ are 79° compared to 77.7(12)° and 77.9(11)° pound crystallises in the orthorhombic space group Pnma
(N7–Ru1–N10 and N13–Ru1–N16, respectively) for the bta with four molecules in the unit cell. The complexes in the
ligand in complex 4.[22] A further discussion of the struc- crystals possess a mirror plane including Re1, Cl1 and C1,
tural data and a comparison with the free ligand 1 is not thus the asymmetric unit contains only one half of the for-
meaningful due to the inaccuracy of the experimental data. mula unit. The ReI atom exists in a distorted octahedral
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Synthesis and Ligand Properties of Bi-1,2,3-triazole Ligands
Figure 9. ORTEP drawing (30% probability ellipsoids) of the struc-
ture of the cation containing Cu2 in the crystals of 7. Selected bond
lengths [Å], angles [°] and torsion angles [°]: Cu2–P3 2.3079(18),
Cu2–P4 2.2292(16), Cu2–N9 2.233(5), Cu2–N10 2.075(6); P3–Cu2–
P4 114.39(7), P3–Cu2–N9 97.32(14), P4–Cu2–N10 130.61(14), N9–
Cu2–N10 78.7(2); N10–C105–C106–N9 3.0(6). As indicated in the
text, one benzyl group is disordered.
Figure 7. Crystal structure of the homoleptic RuII complex cation
of 4 (H atoms, chloride anions and solvent molecules have been
omitted for clarity). Because of the low quality of the structure
no atom distances or torsion angles are discussed (see text and
Supporting Information). Bond angles [°]: N1–Ru1–N4 74.9(12),
N7–Ru1–N10 77.7(12), N13–Ru1–N16 77.9(11), N4–Ru1–N10
100.7(11), N7–Ru1–N16 98.7(12), N1–Ru1–N10 167.5(10), N4–
Ru1–N16 172.5(12), N7–Ru1–N13 172.1(11).
angles of several complexes of the type [(s-bpy)ReI(CO)3X]
(X = anionic or neutral ligand) containing a substituted
bpy ligand [Є(N1–Re–N1Ј) ca. 74°].[24] The bitriazole li-
gand is perfectly planar as a result of the mirror symmetry.
The characteristic bond lengths and angles are normal and
are similar to previously reported values in analogous bpy
complexes.[24]
Figure 8. ORTEP drawing (30% probability ellipsoids) of the struc-
ture of the cation containing Cu1 in the crystals of 7. Selected bond
lengths [Å], angles [°] and torsion angles [°]: Cu1–P1 2.2631(17),
Cu1–P2 2.3016(19), Cu1–N3 2.118(4), Cu1–N4 2.201(5); P1–Cu1–
P2 115.44(7), P1–Cu1–N3 119.68(15), P2–Cu1–N4 113.05(13), N3–
Cu1–N4 78.53(18); N3–C45–C46–N4 14.9(8).
Figure 10. Crystal structure of 8 (H atoms have been omitted for
clarity). Selected bond lengths [Å], angles [°] and torsion angles
[°]: Re1–N1 2.176(6), Re1–Cl1 2.494(2), Re1–C1 1.890(12), Re1–C2
1.907(8), C1–O1 1.175(15), C2–O2 1.161(10); N1–Re1–N1 73.4(2),
Cl1–Re1–N1 81.26(18), Cl1–Re1–C1 175.3(4), N1–Re1–C1 95.0(3),
N1–Re1–C2 99.1(3), C1–Re1–C2 88.1(4), Re1–C2–O2 177.7(6),
Re1–C1–O1 176.9(11); N1–C3–C3Ј–N1Ј 0.0(9).
environment defined by a fac arrangement of the three car-
bonyl groups, the chloride atom and the two nitrogen atoms
of the bta ligand (Figure 10). The distortion from octahe-
dral symmetry essentially arises from the steric demands of
The present crystal structures display the strong similari-
the chelating bta ligand. Again, the bite angle of the bitri- ties of the ligand properties of 2,2Ј-bipyridines and bi-1,2,3-
azole [Є(N1–Re–N1Ј) 73.4(2)°] is very similar to the bite triazoles in terms of steric features.
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Spectroscopic Characterisation
to those of 2,2Ј-bipyridine, although the photophysical
properties are not. The complexes show no luminescence.
Application of these new compounds as bidentate and easy-
to-modify “innocent” ligands may be envisaged. The ligand
properties may be varied using established synthetic routes.
For example, monosubstituted 4,4Ј-bitriazoles could be ob-
tained from 1,4-butadiyne and a mixture of alkyl azide and
trimethylsilyl azide.[28] This would allow the formation of
a triazolyl anion after deprotonation of the unsubstituted
triazole and asymmetric functionalisation. The use of 2,6-
diethynylpyridine instead of 1,4-butadiyne would give ac-
cess to terpyridine analogues, and substitution of the tri-
azole-CH would allow introduction of further functionality
at the ring carbon atom.[29]
All compounds were analysed by NMR, IR and UV/Vis
spectroscopy (see Experimental Section). No 13C NMR
spectra could be recorded for complexes 4, 7 or 8 due to
their low solubility. The proton and carbon signals in the
NMR spectra are in the usual regions, and the IR spectrum
of 8 shows three intense signals at ν = 2018, 1906 and
˜
1866 cm–1, as expected for the vibrations of carbonyl groups
in a facial conformation.[25]
The electronic absorption spectra of ligand 1 and its
complexes with RuII, ReI and CuI are depicted in Figure 11.
Each complex exhibits a low-energy band at λmax = 302 (4,
log ε = 4.549), 272 (7, log ε = 3.883) and 302 (8, log ε =
3.918), and complexes 4 and 7 also exhibit a transition near
the band of the free ligand absorption. The lowest energy
band of complexes 5 and 6 appears at λ = 307 (log ε =
4.517) and 299 nm (log ε = 4.169), respectively (see Fig-
ures S3 and S4 in the Supporting Information). The com-
plexes show absorption peaks between 270 and 370 nm, a
region where no corresponding ligand absorption is found.
We therefore tentatively assign these absorptions to MLCT
bands. It is noteworthy that the maxima of the lowest ab-
sorptions in [(bpy)ReI(CO)3Cl] (λmax = 386 nm)[26] and
[(bpy)3Ru]2+ (λmax = 451 nm)[27] are substantially lower in
energy than in the complexes of ligands 1–3. Poor solubility
Experimental Section
General Information: All reactions were performed under an inert
atmosphere of N2 using standard Schlenk techniques, unless other-
wise stated. Melting points were determined on a Tottoli micro
melting point apparatus and are uncorrected. TLC analyses were
performed on silica gel 60 F-254 with a 0.2-mm layer thickness.
Detection was by UV light at 254/366 nm or by discolouration with
ninhydrin in EtOH. Merck Geduran SI 60 silica gel was used for
preparative column chromatography. Commercially available sol-
vents of standard quality were used. Unless otherwise stated, puri-
in non-polar solvents precludes a more detailed study. None fication and drying was done according to accepted general pro-
cedures.[30] Elemental analyses were carried out by the Centre for
Chemical Analysis of the Faculty of Natural Sciences of the Uni-
versity of Regensburg.
of the complexes is an emitter in solution or the solid state.
Safety Note: Sodium azide is toxic and can generate the extremely
hazardous hydrazoic acid (volatile, toxic, explosive) if it comes into
contact with acids. Organic azides with a saturated carbon:azide ra-
tio of less than 6 may be heat- and shock-sensitive and should be
handled with care.
Absorption spectra were recorded with a Varian Cary BIO 50 UV/
Vis/NIR Spectrometer with a 1-cm quartz cell (Hellma) and Uvasol
solvents (Merck or Baker). NMR spectra were recorded with a
Bruker Avance 300 spectrometer (1H: 300.1 MHz; 13C: 75.5 MHz;
T = 300 K). The chemical shifts are reported in ppm relative to
external standards (solvent residual peak) and coupling constants
are given in Hertz. The spectra were analysed as being first order.
Assignment of signals in the 13C NMR spectra was performed with
the DEPT technique (pulse angle: 135°) and given as (+) for CH3
or CH, (–) for CH2 and (Cquat) for quaternary C. Error of reported
Figure 11. Electronic absorption spectra of compounds 1, 4, 7, and
8 in acetonitrile (c = 20 µ).
values: chemical shift: 0.01 ppm for 1H NMR, 0.1 ppm for 13C
NMR and 0.1 Hz for coupling constants. The solvent used is re-
ported for each spectrum. Mass spectra were recorded with a Var-
ian CH-5 (EI), Finnigan MAT 95 (CI, FAB and FD) or Finnigan
MAT TSQ 7000 (ESI) spectrometer with xenon as the ionisation
gas for FAB. IR spectra were recorded with a Bio-Rad FTS 2000
Summary
New 1,1Ј-disubstituted 4,4Ј-bi-1,2,3-triazole compounds MX FT-IR or Bio-Rad FT-IR FTS 155 spectrometer.
have been synthesised by a CuI-catalysed cycloaddition be-
Synthesis of Triazole Ligands and Complexes. General Procedures:
tween 1,4-butadiyne and various alkyl and aryl azides.
GP 1: Twofold “Click Reaction” with 1,3-Butadiyne: The freshly
These compounds have been employed as ligands for transi-
prepared butadiyne was condensed into 5 mL of acetonitrile at
tion metal complexes. Three homoleptic RuII complexes of
–40 °C and a solution of the azide (2.0 equiv.), 2,4-lutidine
(2.2 equiv.) and CuI (10 mol-%) in 10 mL of acetonitrile was cooled
to –40 °C and added. The reaction mixture was then warmed to
room temperature. The reaction vessel was stored in a closed auto-
the obtained ligands as well as one CuI and ReI complex
with one of the ligands have been synthesised. All of them
are readily accessible by standard reactions and are per-
fectly stable. The steric properties of the ligands are similar clave to prevent evaporation of the butadiyne. After stirring for
4602 Eur. J. Inorg. Chem. 2007, 4597–4606
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© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Synthesis and Ligand Properties of Bi-1,2,3-triazole Ligands
20 h, the mixture was poured into 50 mL of an aqueous solution
of H2O2 (3%). The mixture was stirred until the generation of gas
ceased, then 50 mL of a saturated aqueous solution of EDTA was
added and the mixture was stirred for 30 min. Further purification
was different for each compound.
solution was lyophilized to yield the sodium salt of 3 (2.50 g,
8.4 mmol, 78%). NMR, mass and UV spectra were recorded for
this salt. The solid was dissolved in water (20 mL), the solution was
heated to reflux and 0.5  aqueous HCl was added dropwise until
a precipitate appeared. After cooling to room temperature, 2 
aqueous HCl was added until no further product precipitated. The
solid was filtered, washed with water and dried in vacuo. This
yielded 2.12 g of 3 as colourless crystals (78%). M.p. Ͼ 215 °C
(decomp.). 1H NMR (300 MHz, D2O): δ = 5.05 (s, 4 H, CH2), 8.20
(s, 2 H, triazole) ppm. 13C NMR (75.5 MHz, D2O): δ = 53.3 (–,
GP 2: Synthesis of Homoleptic RuII Complexes: The bitriazole li-
gand (3 equiv.) and RuCl3·4H2O were suspended in ethylene glycol
(10 mL) in a round-bottomed flask (25 mL). The mixture was
heated (oil bath temperature: 200 °C) to yield a dark-red solution,
which slowly turned to brownish orange over 20 h. The solution
was concentrated in vacuo with heating to 3 mL, then boiling etha-
nol was added to the solution at 80 °C until a white precipitate
appeared. The mixture was stored at –20 °C overnight to complete
precipitation, then the solid was separated by centrifugation and
dried in vacuo.
2 C), 123.9 (+, 2 C, triazole), 138.6 (2 C, Cquat), 173.1 (2 C, Cquat
)
ppm. MS (ESI, H2O/MeCN): m/z (%) 253.1 (100) [MH+].
C8H8N6O4 (252.16): calcd. C 38.10, H 3.20, N 33.32; found C
37.97, H 3.32, N 33.17. UV/Vis (H2O): λ (log ε) = 225 nm (4.092).
IR (KBr): ν = 3435, 3151, 3117, 3013, 2947, 2792, 2708, 2594, 2511,
˜
1930, 1794, 1724, 1496, 1420, 1347, 1295, 1257, 1223, 1151, 1109,
1064, 1011, 976, 896, 795 cm–1.
1,1Ј-Dibenzyl-4,4Ј-bi-1H-1,2,3-triazolyl (1): Synthesised following
GP 1 from butadiyne (563 mg, 11.3 mmol), benzyl azide (3.00 g,
22.5 mmol, 2 equiv.), 2,4-lutidine (2.65 g, 2.86 mL, 24.8 mmol,
2.2 equiv.) and CuI (214 mg, 1.13 mmol, 10 mol-%). After workup,
the aqueous solution was extracted with CHCl3 (3ϫ100 mL) and
the organic phase was dried with Na2SO4, filtered and concentrated
at reduced pressure. The crude product was purified by column
chromatography with a dichloromethane/MeOH gradient from
99:1 to 96:4. This yielded 2.93 g of 4 as colourless crystals (82%).
M.p. 228 °C. 1H NMR (300 MHz, [D6]DMSO): δ = 5.67 (s, 4 H,
CH2), 7.31–7.40 (m, 10 H, CH), 8.58 (s, 2 H, triazole) ppm. 13C
NMR (75.5 MHz, [D6]DMSO): δ = 52.8 (–, 2 C), 121.7 (+, 2 C,
triazole), 127.9 (+, 4 C), 128.1 (+, 2 C), 128.7 (+, 4 C), 139.2 (1 C,
Cquat), 142.2 (1 C, Cquat) ppm. MS (ESI, DCM/MeOH): m/z (%)
317.1 (100) [MH+]. C18H16N6 (316.37): calcd. C 68.34, H 5.10, N
26.56; found C 68.21, H 5.21, N 26.42. UV/Vis (MeCN): λ (log ε)
Ru Complex 4: Ligand 1 (100 mg, 0.32 mmol) and RuCl3·3H2O
(28 mg, 0.11 mmol) were suspended in 20 mL of ethylene glycol in
a round-bottomed flask fitted with a reflux condenser and the mix-
ture was heated (oil bath temperature: 200 °C). This yielded a dark-
red solution which slowly turned to brownish orange over 20 h.
The solvent was removed in vacuo by heating. The remaining solid
was dissolved in boiling MeCN and filtered. Et2O was then added
to the solution to precipitate the product. This yielded a light yel-
low powder, which was recrystallised from MeCN/Et2O to give
84 mg of 7 as yellowish crystals (0.07 mmol, 68%). M.p. Ͼ 210 °C
(decomp.). 1H NMR (300 MHz, CD3CN): δ = 5.55 (s, 12 H, CH2),
7.12–7.18 (m, 12 H, CH), 7.28–7.36 (m, 18 H, CH), 8.54 (s, 6 H,
triazole) ppm. MS (ESI, H2O/MeCN): m/z (%) 525.4 (100)
[(L3Ru2+ 2+], 1185.5 (1) [(L3Ru2+ + Cl–)+]. C54H48Cl2N18Ru·4H2O
)
(1193.1): calcd. C 54.36, H 4.73, N 21.13; found C 54.46, H 4.62,
N 20.47. UV/Vis (H2O): λ (log ε) = 302 (4.549), 222 nm (5.143). IR
= 225 nm (4.458). IR (KBr): ν = 3133, 3101, 3031, 2984, 2946,
˜
2858, 1673, 1494, 1439, 1410, 1364, 1293, 1231, 1076, 1058, 949,
(ATR): ν = 3116, 3032, 1446, 1456, 1426, 1356, 1340, 1276, 1112,
˜
836, 722 cm–1.
1078, 1042, 720, 694, 654 cm–1.
1,1Ј-Diphenyl-4,4Ј-bi-1H-1,2,3-triazolyl (2): Synthesised following
GP 1 from butadiyne (335 mg, 6.7 mmol), phenyl azide (1.60 g,
13.4 mmol, 2 equiv.), 2,4-lutidine (1.58 g, 1.70 mL, 14.8 mmol,
2.2 equiv.) and CuI (127 mg, 0.67 mmol, 10 mol-%). After workup,
the aqueous solution was heated to 40 °C and extracted with warm
CHCl3 (40 °C, 8 ϫ80 mL). The organic phase was dried with
Na2SO4, filtered, concentrated at reduced pressure and dried in
vacuo. The residue was dissolved in boiling CHCl3, filtered through
charcoal and Celite and concentrated again. The crude product was
purified by recrystallisation from CHCl3/petroleum ether. This
yielded 1.47 g of 2 as colourless crystals (76%). M.p. 236 °C. 1H
NMR (300 MHz, CHCl3): δ = 7.49 (t, 3J = 7.7 Hz, 2 H, CH), 7.53–
Ru Complex 5: Synthesised following GP 2 from 2 (250 mg,
0.87 mmol) and RuCl3·4H2O (78 mg, 0.29 mmol). This yielded
665 mg of 5 as colourless crystals (74%). M.p. Ͼ 210 °C (decomp.);
1H NMR (300 MHz, [D6]DMSO): δ = 7.54–7.66 (m, 18 H, CH),
3
7.89 (d, J = 7.1 Hz, 12 H, CH), 9.76 (s, 6 H, triazole) ppm. 13C
NMR (75.5 MHz, [D6]DMSO): δ = 120.1 (+, 2 C, triazole), 120.5
(+, 4 C), 129.9 (+, 2 C), 130.0 (+, 4 C), 135.6 (1 C, Cquat), 140.9
(1 C, Cquat) ppm. MS (ESI, H2O/MeCN): m/z (%) 483.2 (100)
[(L3Ru2+ 2+], 1115.4 (5) [(L3Ru2+ + TfO–)+]. UV/Vis (H2O):
)
λ (log ε) = 307 (4.517), 239 nm (5.012). IR (KBr): ν = 3102, 3062,
˜
1595, 1499, 1464, 1422, 1313, 1271, 1065, 999, 760 cm–1.
3
7.59 (m, 4 H, CH), 7.82 (d, J = 7.6 Hz, 4 H, CH), 8.59 (s, 2 H,
Ru Complex 6: Synthesised following GP 2 from 3 (250 mg,
0.99 mmol) and RuCl3·4H2O (90 mg, 0.33 mmol). This yielded
triazole) ppm. 13C NMR (75.5 MHz, CHCl3): δ = 118.9 (+, 2 C,
triazole), 120.6 (+, 4 C), 129.0 (+, 2 C), 129.9 (+, 4 C), 136.9 (1 C, 634 mg of 6 as colourless crystals (69%). M.p. Ͼ 205 °C (decomp.).
Cquat), 140.5 (1 C, Cquat) ppm. MS (ESI, DCM/MeOH): m/z (%) 1H NMR (300 MHz, D2O): δ = 5.22 (s, 12 H, CH2), 8.50 (s, 6 H,
289.1 (100) [MH+]. C16H12N6 (288.31): calcd. C 66.66, H 4.20, N
triazole) ppm. 13C NMR (75.5 MHz, D2O): δ = 51.5 (–, 6 C), 122.0
29.15; found C 66.57, H 4.31, N 29.01. UV/Vis (CH3CN): λ (log ε)
(+, 6 C, triazole), 138.2 (6 C, Cquat), 171.0 (6 C, Cquat) ppm. MS
= 232 (4.480), 257 nm (4.366). IR (KBr): ν = 3132, 3093, 3065, (ESI, H2O/MeCN): m/z (%) 478.2 (100), 507.2 (100), 521.3 (100),
˜
1654, 1597, 1504, 1464, 1396, 1257, 1234, 1034, 825, 756 cm–1.
955.3 (65). UV/Vis (H2O): λ (log ε) = 299 (4.169), 225 nm (4.721).
IR (KBr): ν = 3429. 3136, 2925, 1746, 1629, 1454, 1377, 1288, 1221,
˜
1,1Ј-Bis(carboxymethyl)-4,4Ј-bi-1H-1,2,3-triazolyl (3): Synthesised
following GP 1 from butadiyne (541 mg, 10.8 mmol), β-azidoacetic
acid (2.18 g, 21.6 mmol, 2 equiv.), 2,4-lutidine (2.55 g, 2.75 mL,
1021 cm–1.
CuI Complex 7: Ligand 1 (50 mg, 0.16 mmol), [CuI(NCMe)4]PF6
23.8 mmol, 2.2 equiv.) and CuI (206 mg, 1.08 mmol, 10 mol-%). (59 mg, 0.16 mmol) and bis[2-(diphenylphosphanyl)phenyl] ether
After workup, the aqueous solution was acidified to pH 2 with 6 
aqueous HCl. The precipitate was filtered, washed with water and
suspended in 10 mL of water. A 0.1  aqueous solution of NaOH
was then added dropwise until the solid dissolved completely. The
(85 mg, 0.16 mmol) were dissolved in degassed dichloromethane
and heated to reflux for 3 h. The solution was concentrated and
diethyl ether was added to precipitate the product. The suspension
was filtered and the filtrate cooled to – 35 °C. This gave colourless
Eur. J. Inorg. Chem. 2007, 4597–4606
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4603

U. Monkowius, S. Ritter, B. König, M. Zabel, H. Yersin
FULL PAPER
crystals of 7 suitable for X-ray crystallography. Complex 7 was ob-
tained in an overall yield of 73% (123 mg). 1H NMR (300 MHz,
CD3CN): δ = 5.59 (s, 4 H, CH2), 6.66–6.75 (m, 2 H, CH), 6.90–
7.02 (m, 4 H, CH), 7.25–7.47 (m, 32 H, CH), 8.12 (s, 2 H, triazole)
ppm. 31P NMR (162 MHz, CDCl3): δ = –13.38 ppm. MS (ESI):
m/z (%) 317.1 (8) [1+], 601.2 (28) [(DPEPhos)Cu+], 642.2 (100)
[{(DPEPhos)Cu
C54H44CuN6OP2·PF6 (1063.4): calcd. C 60.99, H 4.17, N 7.90;
+
MeCN}+], 917.4 (51) [(DPEPhos)(1)Cu+].
Table 1. Crystal data, data collection and structure refinement for compounds 1–3.
1 (prisms)
1 (needles)
2
3
Formula
Mw
C18H16N6
316.37
C18H16N6
316.37
C16H12N6
288.32
C8H8N6O4
252.20
Crystal size [mm]
Crystal system
Space group
a [Å]
b [Å]
c [Å]
0.32ϫ0.22ϫ0.18
monoclinic
P21/c
8.1669(10)
9.4871(13)
10.3595(12)
90
94.135(14)
90
800.57(17)
1.311
0.48ϫ0.28ϫ0.02
monoclinic
Cc
34.414(3)
5.5439(5)
8.4506(7)
90
102.466(10)
90
1574.3(2)
1.335
0.42ϫ0.06ϫ0.04
triclinic
P1
0.44ϫ0.02ϫ0.01
monoclinic
P21/c
7.4088(4)
4.5388(3)
14.5860(9)
90
95.767(5)
90
488.00(5)
1.716
¯
5.729(4)
11.019(18)
16.744(14)
101.38(11)
93.17(7)
102.51(11)
1006(2)
1.428
α [°]
β [°]
γ [°]
V [Å3]
ρcalc [gcm–3
]
Z
2
4
3
2
µ [mm–1
T [K]
]
0.083
123
0.085
123
0.741
150
1.221
123
Θ range [°]
Reflections collected
Unique reflections
Observed reflections [I Ͼ 2σ(I)]
Parameters refined/restraints
Absorption correction
Tmax, Tmin
σfin (max./min.) [eÅ–3
R1 [IՆ2σ(I)]
wR2
2.50–26.80
5365
2.42–26.80
6381
2.71–50.31
5716
2062 [R(int) = 0.0298]
1411
6.10–62.10
1756
748 [R(int) = 0.0298]
558
1589 [R(int) = 0.0337] 3264 [R(int) = 0.0854]
1166
109/0
none
2516
217/2
none
298/0
85/0
semi-empirical from equivalents semi-empirical from equivalents
0.6559, 1.0
0.146/–0.213
0.0338
0.4862, 1.0
1.021/–0.299
0.0773
]
0.238/–0.137
0.0333
0.0805
0.294/–0.248
0.0565
0.1401
0.0754
0.2273
CCDC number
645041
645040
645044
645045
Table 2. Crystal data, data collection and structure refinement for compounds 4, 7 and 8.
4
7
8
Formula
Mw
C54H48Cl2N18RuS[a]
–
2(C54H44CuN6OP2) 2(PF6)
2124.87
C21H16ClN6O3Re
622.06
[a]
Crystal size [mm]
Crystal system
Space group
a [Å]
b [Å]
c [Å]
0.36ϫ0.11ϫ0.06
monoclinic
P21/a
16.3417(3)
23.1347(4)
18.0784(5)
90
0.34ϫ0.22ϫ0.14
triclinic
P1
0.11ϫ0.026ϫ0.015
orthorhombic
Pnma
10.475(4)
18.574(7)
10.584(4)
90
90
¯
13.742(1)
14.425(1)
29.195(2)
83.511(9)
86.160(9)
71.812(8)
5459.8(7)
1.294
α [°]
β [°]
107.787(3)
90
γ [°]
90
V [Å3]
6508.0(3)
2059.3(14)
2.006
ρcalc [gcm–3
]
–
[a]
Z
4
–
123
4
4
[a]
µ [mm–1
T [K]
]
0.551
123
13.070
150
Θ range [°]
Reflections collected
Unique reflections
Observed reflections [I Ͼ 2σ(I)]
Parameters refined/restraints
Absorption correction
Tmin, Tmax
σfin (max/min) [eÅ–3
R1 [IՆ2σ(I)]
wR2
3.20–51.54
32311
6840 [R(int) = 0.0455]
4589
2.00–25.00
54865
18094 [R(int) = 0.0969]
6873
5.94–51.16
4576
1081 [R(int) = 0.0935]
889
677/0
1252/0
75/0
semi-empirical from equivalents
analytical from crystal shape
0.8458, 0.9441
0.796/–0.259
0.0562
semi-empirical from equivalents
0.63090, 1.0
1.916/–0.698
0.0817
0.25246, 1.0
1.713/–1.067
0.0449
]
0.2567
0.1461
0.1104
CCDC number
645042
645043
645046
[a] Crystals of 4 contain an unspecified number of solvents, which are highly disordered, thus no formula and no reliable values for the parameters or
formula can be given.
4604
www.eurjic.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 4597–4606

Synthesis and Ligand Properties of Bi-1,2,3-triazole Ligands
Chem. Rev. 2004, 104, 651; S. Welter, N. Salluce, P. Belser, M.
Groeneveld, L. De Cola, Coord. Chem. Rev. 2005, 249, 1327;
R. T. F. Jukes, V. Adamo, F. Hartl, P. Belser, L. De Cola, Co-
ord. Chem. Rev. 2005, 249, 1327; V. Balzani, F. Scandola,
Supramolecular Photochemistry, E. Horwood, Chichester, 1991;
R. Hage, Coord. Chem. Rev. 1991, 111, 161; M. Ruben, S. Rau,
A. Skirl, K. Krause, H. Gorls, D. Walther, J. G. Vos, Inorg.
Chim. Acta 2000, 303, 206; V. J. Catalano, T. J. Craig, Inorg.
Chem. 2003, 42, 321; D. M. D’Alessandro, P. H. Dinolfo, J. T.
Hupp, P. C. Junk, F. R. Keene, Eur. J. Org. Chem. 2006, 4, 772;
H. Yersin, C. Kratzer, Coord. Chem. Rev. 2002, 229, 75.
U. S. Schubert, C. Eschbaumer, Angew. Chem. Int. Ed. 2002,
41, 2892.
H. Yersin, Top. Curr. Chem. 2004, 241, 1; K. W. Lee, J. D.
Slinker, A. A. Gorodetsky, S. Flores-Torres, H. D. Abruna,
P. L. Housten, G. G. Malliaras, Phys. Chem. Chem. Phys. 2003,
5, 2706; L. J. Stoltzberg, J. D. Slinker, S. Flores-Torres, A. D.
Bernards, G. G. Malliaras, H. D. Abruna, J.-S. Kim, R. H.
Friend, M. D. Kaplan, V. Goldberg, J. Am. Chem. Soc. 2006,
128, 7761; C. Zhen, Y. Chuai, C. Lao, L. Huang, D. Zou, D. N.
Lee, B. H. Kim, Appl. Phys. Lett. 2005, 87, 093508/1; F. W.
Vergeer, X. Chen, F. Lafolet, L. De Cola, H. Fuchs, L. Chi,
Adv. Funct. Mater. 2006, 16, 625.
found C 60.54, H 4.23, N 7.74; UV/Vis (MeCN): λ (log ε) = 272 nm
(3.883). IR (ATR): ν = 3138, 2944, 2884, 2364, 2328, 2210, 2162,
˜
2048, 1976, 1498, 1458, 1288, 1260, 1046, 814, 716 cm–1.
ReI Complex 8: Ligand 1 (50 mg, 0.16 mmol) and [ReI(CO)5]Cl
(57 mg, 0.16 mmol) were dissolved in degassed toluene and heated
to reflux for 12 h. After cooling to room temperature, the colourless
precipitate was filtered and dried in vacuo. Recrystallisation from
MeCN/Et2O yielded 8 as colourless crystals (94 mg, 96%). 1H
NMR (300 MHz, CD3CN): δ = 5.72 (s, 4 H, CH2), 7.39–7.46 (m,
10 H, CH), 8.28 (s, 2 H, triazole) ppm. MS (ESI): m/z (%) 91.1
(100) [Bn+], 503.0 (10) [(1)Re+], 538.0 (1) [(M – 3CO + H)+], 566.0
(2) [(M – 2CO + H)+], 593.3 (2) [M – CO+], 621.9 (1) [M+]. IR
[4]
[5]
(ATR): ν = 3136, 2944, 2886, 2018, 1906, 1866, 1494, 1448, 1422,
˜
1292, 1266, 1178, 1158, 1108, 1082, 1050, 818, 744, 698, 660 cm–1.
UV/Vis (MeCN): λ (log ε) = 350 (sh), 302 (3.918), 228 nm (sh).
C21H16ClN6O3Re (622.05): calcd. C 40.55, H 2.59, N 13.51; found
C 40.47, H 2.59, N 13.55.
Crystal Structure Determination: Diffraction data for crystals of
compound 1 (needles and prisms) and complex 7 were collected
with a STOE-IPDS diffractometer[31] with graphite-monochro-
mated Mo-Kα radiation (λ = 0.71073 Å), whereas data for crystals [6]
of 2, 3, 4 and 8 were collected with an Oxford Diffraction Gemini
Ultra CCD diffractometer[32] with multilayer optics and Cu-Kα ra-
diation (λ = 1.5418 Å). Further crystallographic and refinement
data can be found in Tables 1 and 2. The structures were solved by
direct methods (SIR-97)[33] and refined by full-matrix least-squares
on F2 (SHELXL-97).[34] The H atoms were calculated geometrically
and a riding model was applied during the refinement process. The
structure solution of 4 and 8 was handicapped by poor crystal qual-
ity. For 4, the obviously present solvent molecules could not be
identified and were included in the refinement steps as C atoms
(C100–C112) or as Cl atoms. For 8 only the heavy atoms could be
refined with anisotropic displacement factors.
L. De Cola, P. Belser, A. von Zelewsky, F. Vögtle, Inorg. Chim.
Acta 2007, 360, 775; R. T. F. Jukes, B. Bozic, F. Hartl, P. Belser,
L. De Cola, Inorg. Chem. 2006, 45, 8326; S. Welter, F. Lafolet,
E. Cecchetto, F. Vergeer, L. De Cola, ChemPhysChem. 2005, 6,
2417; W. J. Finkenzeller, P. Stoessel, H. Yersin, Chem. Phys.
Lett. 2004, 397, 289; C. A. Bignozzi, R. Argazzi, C. Chiorboli,
S. Roffia, F. Scandola, Coord. Chem. Rev. 1991, 111, 261; D. M.
D’Alessandro, F. R. Keene, Chem. Rev. 2006, 106, 2270; S.
Ranjan, S. K. Dikshit, Transition Met. Chem. 2002, 27, 668; E.
Tfouni, Coord. Chem. Rev. 2000, 196, 281; D. W. Thompson,
J. R. Schoonover, T. J. Meyer, R. Argazzi, C. A. Bignozzi, J.
Chem. Soc. Dalton Trans. 1999, 21, 3729; A. B. Tamayo, S. Ga-
ron, T. Sajoto, P. I. Djurovich, I. M. Tsyba, R. Bau, M. E.
Thompson, Inorg. Chem. 2005, 44, 8723.
P. McCord, A. J. Bard, J. Electroanal. Chem. 1991, 318, 91.
H. Yersin, W. Humbs, J. Strasser, Top. Curr. Chem. 1997, 191,
153.
T. Sajoto, P. I. Djurovich, A. Tamayo, M. Yousufuddin, R.
Bau, M. E. Thompson, Inorg. Chem. 2005, 44, 7992.
J. Li, P. I. Djurovich, B. D. Alleyne, I. Tsyba, N. N. Ho, R.
Bau, M. E. Thompson, Polyhedron 2004, 23, 419; J. Li, P. I.
Djurovich, B. D. Alleyne, M. Yousufuddin, N. N. Ho, J. C.
Thomas, J. C. Peters, R. Bau, M. E. Thompson, Inorg. Chem.
2005, 44, 1713.
[7]
CCDC-645040–645046 contain the supplementary crystallographic
data for this paper. These data can be obtained free of charge from
[8]
The Cambridge Crystallographic Data Centre via www.ccdc.cam.-
ac.uk/data_request/cif.
[9]
[10]
Supporting Information (see also the footnote on the first page of
this article): Cell plot of compound 3 (Figure S1), complete asym-
metric unit of complex 4 (Figure S2), electronic absorption spectra
of compounds 2/5 (Figure S3) and 3/6 (Figure S4).
[11]
[12]
[13]
P. Coppo, E. A. Plummer, L. De Cola, Chem. Commun. 2004,
1774.
Acknowledgments
P. Coppo, M. Duati, V. N. Kozhevnikov, J. W. Hofstraat, L.
De Cola, Angew. Chem. Int. Ed. 2005, 44, 1806.
B. W. D’Andrade, J. Brooks, V. Adamovich, M. E. Thompsom,
S. R. Forrest, Adv. Mater. 2002, 14, 1032; B. W. D’Andrade,
S. R. Forrest, Adv. Mater. 2004, 16, 1585; J. Slinker, A. D. Ber-
nards, P. L. Houston, H. D. Abruna, S. Bernhard, G. G. Malli-
aras, Chem. Commun. 2003, 2392.
Parts of this work were supported by the Bundesministerium für
Bildung und Forschung (BMBF). We also acknowledge financial
support from the DFG (SPP 1118). S.R. thanks the Elitenetzwerk
Bayern for a graduate fellowship.
[14]
[15]
The synthesis of a phenyl-substituted 1,2,3-bitriazole by a ther-
mal cycloaddition has been reported in the literature, although
a mixture of different products was obtained and no analytical
data for this compound are available: L. V. Sokolyanska, A. N.
Volkov, B. A. Trofimov, Khim. Geterotsikl. Soedin. 1979, 6, 849.
F. H. Westheimer, O. T. Benfey, J. Am. Chem. Soc. 1956, 78,
5309; I. Antonini, F. Claudi, G. Cristalli, P. Fianchetti, M. Gri-
fantini, S. Martelli, J. Med. Chem. 1981, 24, 1181; F. Kröhnke,
Synthesis 1976, 1; J. Uenishi, T. Tanaka, K. Nishiwaki, S. Wak-
abayashi, S. Oae, H. Tsukube, J. Org. Chem. 1993, 58, 4382;
C. L. Fraser, N. R. Inastasi, J. J. S. Lamba, J. Org. Chem. 1997,
62, 9314; R.-A. Fallahpour, Eur. J. Inorg. Chem. 1998, 1205; S.
Dholakia, R. D. Gillard, F. L. Wimmer, Polyhedron 1985, 5,
791.
[1] K. Kalyanasundaram, Photochemistry of Polypyridine and Por-
phyrin Complexes, Academic Press, London, 1992.
[2] A. Juris, V. Balzani, F. Barigeletti, S. Campagna, P. Belser, A.
von Zelewsky, Coord. Chem. Rev. 1988, 84, 85; K. P. Balashev,
M. V. Puzyk, V. S. Kotlyar, M. V. Kulikova, Coord. Chem. Rev.
1997, 159, 109; C. E. Housecroft, Compr. Coord. Chem. II 2004,
5, 555; O. S. Wolfbeis, L. J. Weis, M. J. P. Leiner, W. E. Ziegler,
Anal. Chem. 1988, 60, 2028; M. Maestri, D. Sandrini, V. Balz-
ani, L. Chassot, P. Jolliet, A. von Zelewsky, Chem. Phys. Lett.
1985, 122, 375.
[3] J. K. Hurst, Coord. Chem. Rev. 2005, 249, 313; K. Szaciłowski,
W. Macyk, A. Drzewiecka-Matuszek, M. Brindell, G. Stochel,
Chem. Rev. 2005, 105, 2647; L.-N. Ji, X.-H. Zou, J.-G. Liu,
Coord. Chem. Rev. 2001, 216–217, 513; D. B. Rorabacher,
Eur. J. Inorg. Chem. 2007, 4597–4606
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4605

U. Monkowius, S. Ritter, B. König, M. Zabel, H. Yersin
FULL PAPER
[16] T. L. Mindt, H. Struthers, L. Brans, T. Anguelov, C.
Schweinsberg, V. Maes, D. Tourwé, R. Schibli, J. Am. Chem.
Soc. 2006, 128, 15096; B. M. J. M. Suijkerbuijk, B. N. H. Aerts,
H. P. Dijkstra, M. Lutz, A. L. Spek, G. van Koten, J. M.
Klein Gebbink, Dalton Trans. 2007, 1273; P. Wu, V. V. Fokin,
Aldrichimica Acta 2007, 40, 7; V. D. Bock, H. Hiemstra, J. H.
van Maarseveen, Eur. J. Org. Chem. 2006, 51; T. R. Chan, R.
Hilgraf, K. B. Sharpless, V. V. Fokin, Org. Lett. 2004, 6, 2853.
[17] Y. Angell, K. Burgess, Angew. Chem. Int. Ed. 2007, 46, 3649.
[18] H. D. Verkruijsse, L. Brandsma, Synth. Commun. 1991, 21,
657.
[23] L. M. Engelhardt, C. Pakawatchai, A. H. White, P. C. Healy, J.
Chem. Soc. Dalton Trans. 1985, 125.
[24] S. Trammell, P. A. Goodson, B. P. Sullivan, Inorg. Chem. 1996,
35, 1421; P. A. Anderson, F. R. Keene, E. Horn, R. T. Tiekink,
Appl. Organomet. Chem. 1990, 4, 523; V. W.-W. Yam, V. C.-Y.
Lau, K.-K. Cheung, Organometallics 1995, 14, 2749; O. O.
Gerlits, P. Coppens, Acta Crystallogr., Sect. E 2001, 57, m164.
[25] L. H. Staal, A. Oskam, V. Vrieze, J. Organomet. Chem. 1979,
170, 235.
[26] J. V. Caspar, T. J. Meyer, J. Phys. Chem. 1983, 87, 952.
[27] E. M. Kober, B. P. Sullivan, T. J. Meyer, Inorg. Chem. 1984, 23,
2098.
[19] F. J. Cagle Jr., Acta Crystallogr. 1948, 1, 158; L. L. Merritt,
E. D. Schroeder, Acta Crystallogr. 1956, 9, 801; K. Nakatsu, [28] T. Jin, S. Kamijo, Y. Yamamoto, Eur. J. Org. Chem. 2004, 18,
H. Yoshioka, M. Matsui, S. Kosa, S. Ooi, Acta Crystallogr.,
Sect. A 1972, 28, S24; M. H. Chrisholm, J. C. Huffman, I. P.
Rothwell, P. G. Bradley, N. Kress, W. H. Woodruff, J. Am.
Chem. Soc. 1981, 103, 4945; F. E. Kuhn, M. Groarke, E. Ben-
cze, E. Hardtweck, A. Prazeres, A. M. Santos, M. J. Calhorda,
C. C. Romao, I. S. Goncalves, A. D. Lopes, M. Pillinger, Chem.
Eur. J. 2002, 8, 2370.
3789.
[29] Y.-M. Wu, J. Deng, Q.-Y. Chen, Synthesis 2005, 8, 1314.
[30] S. Hünig, G. Märkl, J. Sauer, Einführung in die apparativen
Methoden in der Organischen Chemie, 2nd ed., Würzburg, Re-
gensburg, 1994; Author collective, Organikum, 17th ed., VEB
Deutscher Verlag der Wissenschaften, Berlin, 1988.
[31] STOE (1998) IPDS software, Version 2.89, STOE & CIE
GmbH, Darmstadt, Germany.
[32] CrysAlis CCD, Oxford Diffraction Ltd., Version 1.171.30.3 (re-
lease 12-05-2006 CrysAlis171.NET).
[33] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, J.
Appl. Crystallogr. 1993, 26, 343.
[20] M. A. Sridhar, N. K. Lokanath, J. S. Prasad, K. S. Rangappa,
N. V. A. Kumar, D. G. B. Gowda, Mol. Cryst. Liq. Cryst. Sci.
Technol., Sect. A 1998, 319, 137; Y.-M. Wu, J. Deng, X. Fang,
Q.-Y. Chen, J. Fluorine Chem. 2004, 125, 1415; K. Harju, M.
Vahermo, I. Mutikainen, J. Yli-Kauhaluoma, J. Comb. Chem.
2003, 5, 826.
[21] Q. Zhang, Q. Zhou, Y. Cheng, L. Wang, D. Ma, X. Jing, F.
Wang, Adv. Mater. 2004, 16, 432; T. McCormick, J. Wen-Li, S.
Wang, Inorg. Chem. 2006, 45, 147.
[34] G. M. Sheldrick, SHELXL-97. Program for crystal structure re-
finement, University of Göttingen, Germany, 1997.
Received: May 2, 2007
Published Online: August 20, 2007
[22] D. P. Rillema, D. S. Jones, C. Woods, H. A. Levy, Inorg. Chem.
1992, 31, 2935; M. Biner, H.-B. Bürgi, A. Ludi, C. Röhr, J. Am.
Chem. Soc. 1992, 114, 5197.
4606
www.eurjic.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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