Preparation, characterization, and reactivity of azido complex containing a Tp(tBuNC)(PPh3)Ru fragment and ruthenium-catalyzed cycloaddition of organic azides with alkynes in organic and aqueous media

Article abstract of DOI:10.1021/om300687a

Treatment of the TpRu complex (PPh₃)[Ru]-Cl (1, [Ru] = Tp( ^tBuNC)Ru) with an excess of sodium azide affords the yellow ruthenium azido complex (PPh₃)[Ru]-N₃ (2). The triazolato complexes (PPh₃)[Ru]-N₃C₂(R)₂ (3a, R = Me; 3b, R = Et) are synthesized via [3+2] cycloadditions of 2 with RO ₂CC≡CCO₂R. Complete characterization of these triazolato complexes elucidates the structures and establishes the N(2)-bonding type of the addition products. Alkylation of 3a with organic bromides causes cleavage of the Ru-N bond and affords 1,4,5-trisubstituted triazoles. Moreover, addition of CS₂ to 2 produces thermally unstable thiothiatriazolate (PPh₃)[Ru]-N₃CS(S) (5), which converts to the isothiocyanate complexes (PPh₃)[Ru]-NCS (6) and (^tBuNC) [Ru]-NCS (7). Other reagents also react with 2, but the products do not result from [3+2] cycloadditions. Terminal alkynes undergo ligand substitution reactions rather than a [3+2] cycloaddition with 2 in the presence of H ₂O to produce the carbonyl complexes (CO)[Ru]-CH₂R (8a, R = Ph; 8b, R = 4-CH₃Ph) through ruthenium vinylidene intermediates. Reaction of 2 with H-C≡C-CMe₂OH in MeOH gives the cationic Fischer carbene complex {(PPh₃)[Ru]=C(OMe)-HC=C(Me)₂} ⁺ (10). In contrast, reaction of H-C≡C-CH₂CH ₂OH gives rise to the five-membered cyclic oxycarbene complex {(PPh₃)[Ru]=C₄H₆O}⁺ (11). Several cationic imine complexes {(^tBuNC)[Ru]-(NH=CHR′)}⁺ (12a, R′ = H; 12b, R′ = CH₃; 12c, R′ = Ph) are formed by the reaction of RCH₂X with 2. If the reaction of 2 with CH₃I is carried out at 35 °C for 24 h, (^tBuNC)[Ru]-I (13) could be isolated. Preliminary results on the catalytic activity of 2 are also presented. Complex 2 catalyzes cycloaddition of alkynes and benzyl azide to give the triazoles in organic and aqueous medium. The structures of 1, 2, 3a, 7, 8a, 10, 11, 12b, 12c, and 13 have been determined by X-ray diffraction analysis.

Full text of DOI:10.1021/om300687a

Article
pubs.acs.org/Organometallics
Preparation, Characterization, and Reactivity of Azido Complex
Containing a Tp(tBuNC)(PPh3)Ru Fragment and Ruthenium-Catalyzed
Cycloaddition of Organic Azides with Alkynes in Organic and
Aqueous Media
Yih-Hsing Lo,* Tsang-Hsiu Wang, Chia-Yi Lee, and Ying-Hsuan Feng
Department of Applied Physics and Chemistry, Taipei Municipal University of Education, Taipei 10048, Taiwan, Republic of China
S
* Supporting Information
ABSTRACT: Treatment of the TpRu complex (PPh3)[Ru]-Cl (1, [Ru] = Tp(tBuNC)Ru) with an excess of sodium azide
affords the yellow ruthenium azido complex (PPh3)[Ru]-N3 (2). The triazolato complexes (PPh3)[Ru]-N3C2(R)2 (3a, R = Me;
3b, R = Et) are synthesized via [3+2] cycloadditions of 2 with RO2CCCCO2R. Complete characterization of these triazolato
complexes elucidates the structures and establishes the N(2)-bonding type of the addition products. Alkylation of 3a with organic
bromides causes cleavage of the Ru−N bond and affords 1,4,5-trisubstituted triazoles. Moreover, addition of CS2 to 2 produces
thermally unstable thiothiatriazolate (PPh3)[Ru]-N3CS(S) (5), which converts to the isothiocyanate complexes (PPh3)[Ru]-
NCS (6) and (tBuNC)[Ru]-NCS (7). Other reagents also react with 2, but the products do not result from [3+2]
cycloadditions. Terminal alkynes undergo ligand substitution reactions rather than a [3+2] cycloaddition with 2 in the presence
of H2O to produce the carbonyl complexes (CO)[Ru]-CH2R (8a, R = Ph; 8b, R = 4-CH3Ph) through ruthenium vinylidene
intermediates. Reaction of 2 with H-CC-CMe2OH in MeOH gives the cationic Fischer carbene complex {(PPh3)[Ru]
C(OMe)-HCC(Me)2}+ (10). In contrast, reaction of H-CC-CH2CH2OH gives rise to the five-membered cyclic oxycarbene
complex {(PPh3)[Ru]C4H6O}+ (11). Several cationic imine complexes {(tBuNC)[Ru]-(NHCHR′)}+ (12a, R′ = H; 12b,
R′ = CH3; 12c, R′ = Ph) are formed by the reaction of RCH2X with 2. If the reaction of 2 with CH3I is carried out at 35 °C for
24 h, (tBuNC)[Ru]-I (13) could be isolated. Preliminary results on the catalytic activity of 2 are also presented. Complex 2
catalyzes cycloaddition of alkynes and benzyl azide to give the triazoles in organic and aqueous medium. The structures of 1, 2,
3a, 7, 8a, 10, 11, 12b, 12c, and 13 have been determined by X-ray diffraction analysis.
from the fact that they are key intermediates in catalytic and
stoichiometric transformations of organic molecules. Further-
more, they are readily accessible from propargylic alcohols and
terminal alkynes. A key characteristic of all these complexes,
particularly if they are cationic, is the electrophilicity of the Cα,
adding, often easily, amines,17 alcohols,18 phosphines,19 and
even fluoride.20 In this way heteroatom-stabilized carbene
complexes become readily available.
Many coligands in TpRu complexes have not been used
other than phosphines, amines, and diene. We are interested in
the σ-donor coligand isocyanide and have begun to investigate
the use of Tp(tBuNC)(PPh3)Ru-N3 as a starting material.
Herein, we report the [3+2] cycloaddition reactions of alkynes
with the ruthenium azido complex (PPh3)[Ru]-N3 (2, [Ru] =
Tp(tBuNC)Ru). The stable triazolato products obtained in all
INTRODUCTION
■
Triazoles are nitrogen heteroarenes that have found a range of
important applications in the pharmaceutical and biochemical
industries,1 as corrosion inhibitors,2 and as energetic materials.3
The most widely used method for synthesis of triazoles involves
the thermal [3+2] cycloaddition of organic azides with alkynes
pioneered by Huisgen.4 Analogously, metal-coordinated azido
ligands can also undergo [3+2] cycloaddition with carbon−
carbon and carbon−heteroatom multiple bonds, frequently
under very mild conditions.5−14 Although such reactions are
studied extensively in synthetic organic chemistry, [3+2]
cycloaddition reactions of azide-coordinated metal complexes
are relatively unexplored. A few reports appeared on cyclo-
addition of alkynes to ruthenium azido complexes in recent
years.15
Ruthenium allenylidene and vinylidene complexes play an
important role in organometallic chemistry, as emphasized in
several recent reviews.16 Interest in these compounds stems
Received: July 25, 2012
Published: September 17, 2012
© 2012 American Chemical Society
6887
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
cases were N(2)-bound. Additionally, we first attempted to
prepare the N(2)-bound 4-substituted-1,2,3-triazolato species
with a Tp(tBuNC)(PPh3)Ru fragment by the reactions with
terminal alkynes. These reactions, however, did not take place.
Terminal alkynes undergo a ligand substitution reaction rather
than a [3+2] cycloaddition with 2 in the presence of H2O
through ruthenium vinylidene intermediates. To our knowl-
edge, this is the first example of a ruthenium azide complex
with terminal alkynes yielding a thermally stable, pure, and
high-yield carbonyl product. We also describe the reaction of 2
with CH3I to give a rare cationic methyleneimine complex of
ruthenium, and a preliminary account of the catalytic activity of
2 is given. Finally, representative structures have been
determined by X-ray crystallography.
Reaction of 1 with an excess of sodium azide in methanol
under refluxing conditions for 24 h affords the yellow azido
complex (PPh3)[Ru]-N3 (2) with an isolated yield of 99%
(Scheme 1). In the IR spectrum, the asymmetric N3 stretching
band appears at 2052 cm−1, consistent with the generally
observed range of 2050−2070 cm−1.23 The 31P NMR spectrum
of 2 displays a singlet resonance at δ 51.4. Complex 2 was
characterized by a single-crystal X-ray diffraction analysis
(Table 1, Supporting Information); an ORTEP drawing is
shown in Figure 2. Selected bond distances and angles are given
in the figure caption. The Ru−N3 bond distance is 2.215(5) Å.
The two N−N bonds (0.948(6) Å for N(7)−N(8) and
1.282(8) Å for N(8)−N(9)) are significantly different. These
bond distances are similar to those found in the azide complex
(PPh3)(CH3CN)[Ru]-N3 (1.054(5) and 1.235(6) Å).24
RESULTS AND DISCUSSION
Synthesis of 4,5-Disubstituted Triazolato Complexes.
As shown in Scheme 2, the N(2)-bound 4,5-bis-
(methoxycarbonyl)-1,2,3-triazolato complex (PPh3)[Ru]-
N3C2-(CO2Me)2 (3a) is obtained via reaction of 1 with
dimethyl acetylene dicarboxylate in CH2Cl2 at room temper-
ature for 3 h. The formation of 3a was readily confirmed by the
disappearance of the characteristic azide IR absorption and the
appearance of sharp peaks at 1433 and 1736 cm−1,
corresponding to the characteristic stretching frequency of
NN and CO groups, respectively. The structure of 3a is
clearly established as the N(2)-bound isomer from the
■
Preparation of the Azido Complex. Treatment of the
TpRu complex Tp(PPh3)2Ru-Cl21 reacts with tert-butyl
isocyanide in CH2Cl2, affording (PPh3)[Ru]-Cl (1, [Ru] =
Tp(tBuNC)Ru). Bright yellow crystals were obtained by slow
diffusion of hexane into a CHCl3 solution at room temperature,
and the molecular structure of 1 has been determined by X-ray
diffraction analysis (Table 1, Supporting Information). An
ORTEP-type view of the neutral complex is shown in Figure 1,
1
appearance of its H NMR spectrum, which shows a singlet
1
at δ 3.77 for the six methoxycarbonyl protons. The H NMR
spectrum of a N(1)-bound isomer would exhibit two
resonances for its anisochronous methoxycarbonyl groups. It
should be noted that the triazole anion could be coordinated to
the metal through either its N(1) or N(2) nitrogen atoms,25
which are essentially isoenergetic, as indicated by molecular
orbital calculations.26 Evidence obtained to date indicates that
either the two isomers, N(1)- and N(2)-bonded, are formed
simultaneously27 or only the N(2)-bound isomer is produced
exclusively.28 In our case, the N(2)-bound isomer is produced
exclusively. By monitoring the reaction with 31P NMR
spectroscopy, two singlet resonances at δ 52.3 and 52.9
attributed to the N(1)- and N(2)-bound isomers, respectively,
were observed at the initial stage of the reaction. The N(1)-
bound isomer, after hours at room temperature, converted to
the N(2)-bound isomer. The FAB mass spectrum displays a
parent peak at m/z 844.2 (M+). In the 13C NMR spectrum, the
triazolato ligand carbon signal appears at δ 140.2. Complex 3a
was characterized by a single-crystal X-ray diffraction analysis
(Table 1, Supporting Information); an ORTEP drawing is
shown in Figure 3. Selected bond distances and angles are given
in the figure caption. The triazolato ligand is N(2)-bound to
ruthenium, and a significant delocalization of the bond in the
triazole ring of compound 3a is evident from the comparable
bond length of the ring atoms. The Ru(1)−N(7) bond distance
Figure 1. ORTEP drawing of 1 with thermal ellipsoids shown at the
50% probability level. Chloroform molecules are omitted for clarity.
Selected distances [Å] and angles [deg]: Ru(1)−N(1) 2.157(6),
Ru(1)−N(3) 2.115(6), Ru(1)−N(5) 2.092(7), Ru(1)−C(10)
1.936(9), Ru(1)−Cl(1) 2.4196(19), Ru(1)−P(1) 2.3153(19);
Ru(1)−C(10)−N(7) 174.3(8), N(1)−Ru(1)−N(3) 84.1(2), N(1)−
Ru(1)−N(5) 89.1(2), N(3)−Ru(1)−N(5) 84.6(2).
(2.074(3) Å) is comparable to those in (η5-C5H5)(dppe)Ru-
15a
N3C2-(CO2Me)2
and other ruthenium triazolato com-
plexes.24,29 The bond angle C(28)−N(10)−C(29) of
161.3(4)° is surprisingly small for an sp-hybridized C atom.
Similarly, the preparation of N(2)-bound 4,5-bis-
(ethoxycarbonyl)-1,2,3-triazolato complex (PPh3)[Ru]-
N3C2(CO2CH2CH3)2 (3b) was accomplished with high yield
by treating 2 with diethylacetylenedicarboxylate. The formation
of the complex was readily confirmed by the disappearance of
the characteristic azide peak and the subsequent appearance of
sharp peaks at 1735 and 1434 cm−1 corresponding to the
and selected bond distances and angles are given in the figure
caption. The environment about the ruthenium metal center
corresponds to a slightly distorted octahedron, and the bite
angle of the Tp ligand produces an average N−Ru−N angle of
85.93°, only slightly distorted from 90°. One of the Ru−N(Tp)
bond lengths (2.157(6) Å) is slightly longer than the other two
22
t
due to the trans influence of the BuNC ligand.
6888
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
Scheme 1
CH2C6F5; 4d, R = CH2CO2CH3). The structures of these free
triazoles are clearly established as N(1)-alkylated from the
appearance of their 1H NMR spectra, which exhibit two proton
resonances for their anisochronous methoxycarbonyl groups. It
was hoped that this type of reaction could be developed into a
high-yield synthetic procedure for the exclusive preparation of
1,4,5-trisubstituted triazole. This hope was partially realized. We
successfully synthesized the 1,4,5-trisubstituted triazole from
3a, but the isolation failed. The free triazoles 4a−d, which mix
with excess organic halides in n-hexane, are hard to isolate.
Alkylation of triazolato cobalt chelate complexes was done by
Nelson and co-workers,28 but isolation of the free triazole was
not successful either.
Reaction of 2 with CS2. Reaction of 2 with excess CS2
gives rise to thiothiatriazolate complex (PPh3)[Ru]-N3CS(S)
(5) via a [3+2] cycloaddition of a CS bond with the azido
group; however, complex 5 could not be isolated in pure form
due to its low thermal stability; instead, thiocyanato complexes
(PPh3)[Ru]-NCS (6) and (tBuNC)[Ru]-NCS (7) were
obtained after a prolonged reaction time (Scheme 2). The
reaction was monitored by NMR spectroscopy. In the 31P
NMR spectrum, the resonance of 5 at δ 50.8 disappeared and
the resonance of 6 at δ 43.9 appeared. In the 1H NMR
spectrum, the hydrogen atom of the C(CH3)3 group of 5 at δ
1.41 disappeared and the resonance at δ 1.49 attributed to
complex 6 appeared. The FAB mass spectrum of 5 shows the
parent peak at m/z 778.1 as well as peaks at m/z 660.1 and
635.1 due to loss of a N3CS(S) and tBuNC ligand, respectively.
The FAB mass spectrum of 6 shows the parent peak at m/z
718.1. The thiothiatriazolate complexes from reaction of metal
azido complexes with CS2 have been reported.23−25 Complex 7
was characterized by a single-crystal X-ray diffraction analysis
(Table 1, Supporting Information); an ORTEP drawing is
shown in Figure 4. Selected bond distances and angles are given
in the figure caption. The thiocyanato ligand is N-bound to
ruthenium. Generally, ruthenium thiocyanate complexes form
N-bound linkage isomers,30 but many S-bound thiocyanate
ruthenium complexes are also known.31
Figure 2. ORTEP drawing of 2 with thermal ellipsoids shown at the
50% probability level. Selected distances [Å] and angles [deg]:
Ru(1)−N(1) 2.125(4), Ru(1)−N(3) 2.128(4), Ru(1)−N(5)
2.091(4), Ru(1)−N(7) 2.215(5), N(7)−N(8) 0.948(6), N(8)−N(9)
1.282(8); Ru(1)−N(7)−N(8) 125.1(5), N(7)−N(8)−N(9) 177.9(7).
characteristic stretching frequency of CO and NN,
1
respectively. The H NMR spectrum shows a quartet at δ
4.21 and a triplet at δ 1.18 assignable to the methylene and
methyl protons of the triazole groups. The 31P NMR resonance
of 3b appears at δ 52.7. The FAB mass spectrum displays a
parent peak at m/z 872.2 (M+).
Synthesis of Organic 1,4,5-Trisubstituted Triazoles.
There is no reaction between organic iodides with 3a, but
treatment of 3a with CH3CH2Br in CDCl3 at room
temperature in a 5 mm NMR tube causes cleavage of the
Ru−N bond and affords a N(1)-alkylated five-membered-ring
organic triazole, N3(CH2CH3)C2(CO2Me)2 (4a), and (PPh3)-
[Ru]-Br (Scheme 2). In the 31P NMR spectrum, the resonance
of 3a at δ 51.7 disappeared and the resonance at δ 50.4
attributed to (tBuNC)[Ru]-Br appeared. In the 1H NMR
spectrum of 4a, two singlet resonances appear at 3.95 and 3.87,
attributed to two anisochronous methoxycarbonyl groups. The
FAB mass spectrum of 4a displays a parent peak at m/z 214.1
(M+ + 1). Similar reaction of 3a with other organic bromides
gives (tBuNC)[Ru]-Br and N(1)-alkylated five-membered-ring
organic triazole N3(R)C2(CO2Me)2 (4b, R = CH2Ph; 4c, R =
Reaction of 2 with Terminal Alkynes. No reaction was
observed between 2 and HCCPh in CH2Cl2, even under
drastic, vigorous conditions. However, a similar reaction in
CH3OH did not yield the expected N(2)-bound 4-phenyl-1,2,3-
triazolato complex (PPh3)[Ru]-N3C2HPh via [3+2] cyclo-
addition, but instead gave the carbonyl complex (CO)[Ru]-
CH2Ph (8a) (Scheme 3). The spectroscopic data were
sufficient to unequivocally assign the structure of 8a. The IR
spectrum of 8a in KBr contains two strong bands at 1949 and
2178 cm−l, corresponding to the characteristic stretching
1
frequency of CO and NC groups, respectively. The H
NMR spectrum of 8a displays two doublet resonances centered
at δ 2.82 and 2.40 with a coupling constant of JH−H = 9.21 Hz
assignable to the gem-protons of the CH2Ph group and further
6889
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
Scheme 2
Figure 4. ORTEP drawing of 7 with thermal ellipsoids shown at the
50% probability level. Selected distances [Å] and angles [deg]:
Ru(1)−N(1) 2.074(2), Ru(1)−N(3) 2.111(2), Ru(1)−N(5)
2.118(2), Ru(1)−N(7) 2.062(2), N(7)−C(10) 1.155(3), C(10)−
S(1) 1.639(3); Ru(1)−N(7)−C(10) 176.3(2), N(7)−C(10)−S(1)
178.8(3).
Figure 3. ORTEP drawing of 3a with thermal ellipsoids shown at the
50% probability level. Selected distances [Å] and angles [deg]:
Ru(1)−N(1) 2.136(3), Ru(1)−N(3) 2.108(3), Ru(1)−N(5)
2.099(3), Ru(1)−N(7) 2.074(3), N(7)−N(8) 1.325(4), N(7)−N(9)
1.346(4); Ru(1)−N(7)−N(8) 122.3(3), N(8)−N(7)−N(9) 113.1(3),
C(28)−N(10)−C(29) 161.3(4).
distances and angles are given in the figure caption. The bond
angle C(11)−N(10)−Ru(1) of 119.8(5)° is surprisingly large
for an sp3-hybridized C atom.
Formation of carbonyl complex 8a may proceed by initial
formation of a cationic vinylidene complex {(PPh3)[Ru][
CC(H)Ph]}N3 A and subsequent addition of H2O to
produce an acyl complex (PPh3)[Ru](COCH2Ph) B derived
from the elimination of HN3, followed by a deinsertion of CO
from the acyl ligand (Scheme 3). Herein, HCCPh behaves as
13C NMR signals of CO and NC carbons at δ 204.7 and 152.6,
respectively. Complex 8a was characterized by a single-crystal
X-ray diffraction analysis (Table 1, Supporting Information).
Figure 5 shows the ORTEP drawing of 8a, which involves
carbonyl (CO) and benzyl (CH2Ph) ligands. Selected bond
6890
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
Scheme 3
ruthenium azide complex with terminal alkyne yielding a
thermally stable, pure, and high-yield carbonyl product.
Similarly, treatment of 2 with a 5-fold excess of p-
tolylacetylene in CH2Cl2 at room temperature for 5 h afforded
the carbonyl complex (CO)[Ru]-CH2(p-CH3C6H4) (8b). The
IR spectrum of 8b shows a band at 1943 cm−1, due to the CO
group. The 1H NMR spectrum of 8b in CDCl3 shows a doublet
at δ 2.78 and 2.37 with JH−H = 17.2 Hz, assigned to the gem-
protons of the CH2(p-CH3C6H4) group.
Reaction of 2 with Terminal Alkynols. The azido
complex 2 reacted with an excess of HCCCH2OH in
CH3OH at room temperature. The reaction mixture turned
deep green in color after 1 h. Continued stirring up to 5 h
ensured complete reaction. This afforded the carbonyl complex
(CO)[Ru]-C(H)CH2 (9) in good yield (Scheme 3). The
formation of 9 would consist in the initial formation of the
allenylidene intermediate {(PPh3)[Ru][CCCH2]}N3 C
through dehydration of the γ-OH group and subsequent
nucleophilic attack of an adventitious water molecule onto its
α-carbon, giving ethenylcarbonyl intermediate (PPh3)[Ru][-
C(O)-CHCH2] D derived from the elimination of HN3,
followed by a deinsertion of CO from the acyl ligand to afford
the final product 9. By monitoring the reaction with 31P NMR
spectroscopy, two singlet resonances at δ 41.3 and 46.9
attributed to the cationic allenylidene and aceyl complexes,
respectively, were observed at the initial stage of the reaction.
The FAB mass spectrum of 9 shows the parent peak at m/z
454.1 as well as peaks at m/z 427.1 due to loss of a HCCH2
ligand.
Intriguingly, reaction of 2 with H-CC-CMe2OH in the
presence of KPF6 in CH3OH gives the cationic Fischer carbene
complex {(PPh3)[Ru]C(OMe)-HCC(Me)2}(PF6) (10).
The formation of 10 may proceed by initial formation of an
allenylidene intermediate {(PPh3)[Ru][CCCMe2]}PF6,
and subsequent addition of CH3OH onto its α-carbon gives the
final product 10 (Scheme 4). Complex 10 was characterized by
a single-crystal X-ray diffraction analysis (Table 2, Supporting
Information); an ORTEP drawing is shown in Figure 6.
Selected bond distances and angles are given in the figure
Figure 5. ORTEP drawing of 8a with thermal ellipsoids shown at the
50% probability level. Selected distances [Å] and angles [deg]:
Ru(1)−N(1) 2.155(6), Ru(1)−N(3) 2.143(6), Ru(1)−N(5)
2.168(6), Ru(1)−C(10) 2.153(7), Ru(1)−C(22) 1.857(8), C(22)−
O(1) 1.137(8); Ru(1)−C(22)−O(1) 178.1(7), Ru(1)−C(10)−C(11)
119.8(5).
a C−H acid and undergoes a ligand substitution reaction rather
than a [3+2] cycloaddition with 2 in the presence of H2O. The
acyl intermediate was assumed from the fact that formation of
an acyl as the product of the protonation of alkynyl complexes
has been found in several instances and takes place by the
reaction of a highly reactive vinylidene intermediate with traces
of water.32 The H NMR spectrum of B shows two doublet
1
resonances at δ 3.87 and 3.65 with JH−H = 17.2 Hz, assignable
to gem-protons of the CH2Ph group. The 31P{1H} NMR
spectrum shows a singlet resonance at δ 56.3. Metal-mediated
CC triple-bond cleavages of terminal alkynes have been well-
described in the literature,33 and it was determined that these
observed results were associated with intervention of vinylidene
intermediates and with succeeding nucleophilic attacks of water
molecules. To our knowledge, this is the first example of a
6891
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
Scheme 4
t
protons of the BuNC group at δ 1.39. With the help of 2D-
NMR experiments, the signals of the six protons of the five-
1
membered tetrahydrofuranylidene are located in the H NMR
spectrum as two multiplets at δ 5.07−4.99 and 4.65−4.57 for
RuC-CH2, two multiplets at δ 2.12−2.07 and 1.89−1.82 for
RuC-CH2CH2, and two multiplets at δ 3.24−3.15 and 2.90−
2.79 ppm for RuC-OCH2. In the 13C{1H} NMR spectrum of
complex 11, the four carbon atoms of the five-membered oxa
ring show a doublet at δ 316.1 (Cδ, JCP = 14.1 Hz), which
indicates the presence of RuC.34 Consistent with this
structure are the three singlets at δ 83.6 (RuC-CH2), 22.6
(RuC-CH2CH2), and 54.6 (RuC-OCH2); the 31P{1H}
NMR spectrum displays a singlet at δ 48.2, and the FAB mass
spectrum shows the parent peak of the complex cation of 11 at
m/z 730.1 (M+ − PF6). The structure of 11 has been confirmed
by an X-ray diffraction study. Yellow single crystals of complex
11 suitable for X-ray diffraction analysis were obtained via slow
diffusion of hexane into a CH2Cl2 solution of complex 11. The
crystal data and refinement details are given (Table 2,
Supporting Information). An ORTEP view of the cation of
complex 11 is shown in Figure 7. Selected bond distances and
angles are given in the figure caption. The coordination
geometry around ruthenium in 11 can be viewed as a distorted
Figure 6. ORTEP drawing of 10 with thermal ellipsoids shown at the
50% probability level. Selected distances [Å] and angles [deg]:
Ru(1)−N(1) 2.172(4), Ru(1)−N(3) 2.108(4), Ru(1)−N(5)
2.142(4), Ru(1)−C(33) 1.966(6), C(33)−C(36) 1.468(9), C(36)−
C(37) 1.365(16); Ru(1)−C(33)−C(36) 120.7(5), C(33)−C(36)−
C(37) 118.3(10), Ru(1)−C(28)−N(7) 171.5(7).
t
octahedron with a Tp ligand, a PPh3 ligand, a BuNC ligand,
and an oxocarbene ligand. The Ru−C(33) bond distance is
1.948(4) Å and comparable to other oxacycloalkylidene
ruthenium complexes. For instance, the RuC bond distances
in [RuCp(dppe)(C4H6O)]+ and [RuCp(dppe)(
C5H8O)]+ featuring five- and six-membered oxacyclocarbene
ligands are 1.92(1) and 1.938(4) Å, respectively.35 The Ru(1)−
P(1) and Ru(1)−C(10) bond lengths are 2.3534(10) and
1.952(5) Å.
A plausible mechanism for the formation of complex 11 from
complex 2 and HCCCH2CH2OH is shown in Scheme 4.
Complex 2 could coordinate HCCCH2CH2OH, followed by
rearrangement to give the vinylidene intermediate. Subsequent
intramolecular addition of the hydroxyl group to the α-carbon
of the vinylidene ligand could generate 11.
caption. The bond angle Ru(1)−C(33)−C(36) of 120.7(5)° is
an idealized carbon sp2 hybridization. The C(33)−C(36) and
C(36)−C(37) bond lengths are 1.468(9) and 1.365(16) Å,
respectively, compared with those found for the C−C and C
C bond lengths.
Moreover, the reaction of complex 2 with HC
CCH2CH2OH in the presence of KPF6 in refluxing methanol
for 4 h afforded the five-membered cyclic oxycarbene complex
{(PPh3)[Ru]C4H6O}(PF6) (11) (Scheme 4). Several
reactions of ruthenium complexes with terminal alkynols to
give oxocyclocarbene complexes have been reported.34 The 1H
NMR spectrum of complex 11 displays the signals of nine
Alkylation Reactions of 2. Recently, we reported that
during protonation of ruthenium azido complex Tp(PPh3)-
6892
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
Scheme 5
Figure 7. ORTEP drawing of 11 with thermal ellipsoids shown at the
50% probability level. Selected distances [Å] and angles [deg]:
Ru(1)−N(1) 2.124(3), Ru(1)−N(3) 2.183(4), Ru(1)−N(5)
2.133(4), Ru(1)−C(33) 1.948(4), C(33)−C(34) 1.497(7), C(34)−
C(35) 1.536(8), C(35)−C(36) 1.504(9), C(36)−O(1) 1.482(7),
C(33)−O(1) 1.301(6); Ru(1)−C(33)−O(1) 120.9(3), C(33)−
O(1)−C(36) 113.3 (4), Ru(1)−C(10)−N(7) 174.8(5).
Similarly, treatment of 2 with a 5-fold excess of CH3CH2I
and PhCH2Br in CH2Cl2 at room temperature for 5 h afforded
the cationic imine complexes {(tBuNC)[Ru]-(NHCH-
(CH3))}+ (12b) and {(tBuNC)[Ru]-(NHCH(Ph))}+
(12c), respectively. Good analytical data were obtained for
cationic imine complexes 12b,c, which are bright yellow solids
stable in air and in solution of polar organic solvents.
Characteristic spectroscopic data of these imine complexes
consist of a weak-intensity NH band at 3181 10 cm−1 in the
IR spectrum and a doublet signal for the hydrogen atom of the
imine function (NHCH) at δ 11.50 1 as a doublet owing
to coupling with the signals at δ 6.50 0.5 (NHCH) in the
1H NMR spectrum. Conclusive support for the formulation of
12b,c came from the X-ray diffraction analysis (Table 2,
Supporting Information). An ORTEP view of the cation of
complexes 12b and 12c is shown in Figures 8 and 9,
respectively. Selected bond distances and angles are given in
the figure captions. The bond angles C(20)−N(9)−Ru(1) of
130.3(5)° in 12b and 127.0(5)° in 12c are surprisingly large for
an sp2-hybridized N atom, but similar values have been found
for the above-mentioned ruthenium complex cis-[Ru(NH
CH2)(NCCH3)(bpy)2]2+ (135.4(7)°).37 The CN bond
distances are 1.272(9) Å in 12b and 1.288 (9) Å in 12b,
compared with those found in imine moieties coordinated to a
metal center (1.25−1.31 Å).39
If the reaction of 2 with CH3I is carried out at 35 °C for 24 h,
(tBuNC)[Ru]-I (13) could be isolated. The complex 12a at 35
°C for 20 h could give the same result. Methyleneimine was not
observed. Methyleneimine is known to be a reactive molecule,
and its existence can be recognized only at low temperatures by
IR spectroscopy.40 The product 13 is established by a single-
crystal X-ray diffraction study (Table 2, Supporting Informa-
tion). An ORTEP diagram is shown in Figure 10, and selected
bond distances and angles are given in the figure caption.
Cycloaddition of Alkynes and Organic Azides in
Organic and Aqueous Media. In contrast to the click
reactions promoted by copper, the ruthenium complex
(PhCN)Ru-N3, methylene insertion accidentally took place, to
yield unusual boron-methylated product MeTp(PPh3)(PhCN)-
Ru-Cl through coordinatively unsaturated intermediate Tp-
(PPh3)RuCl2.36 However, reaction of 3a with HCl affords 2 via
elimination of HN3. Reaction of 2 with a 5-fold excess of CH3I
in CH2Cl2 gave rise to the cationic methyleneimine complex
{(tBuNC)[Ru]-(NHCH2)}+ (12a) (Scheme 5). The other
product, [Ph3PMe]I, was detected by 1H NMR (δ 3.1, d, JP−H
=
14.6 Hz; Ph3PMe). The previous example of ruthenium
methyleneimine complex cis-[Ru(NHCH2)(NCCH3)-
(bpy)2]2+ was reported by Nagao et al.37 An intermediate,
{(PPh3)[Ru]-(NHCH2)}+ F, was observed in the initial
stage of the reaction monitored by spectroscopic methods. The
1H NMR spectrum of F shows one dd resonance at δ 11.58
(JH−H = 21.4, 12.6 Hz), assigned to the imine proton (NH
CH2), and two resonances displaying doublets at δ 7.66 and
6.76, assigned to the methylene group (NHCH2). The
31P{1H} NMR spectrum displays a singlet at δ 49.8, and the
FAB spectrum shows the parent peak of the complex cation of
F at m/z 698.1. Complex 12a is thermally robust and stable
both in solution and in the solid state. In the 1H NMR
spectrum of 12a, a dd resonance at δ 12.86 (JH−H = 20.0, 13.0
Hz) is assigned to the imine proton (NHCH2), and two
resonances displaying doublets at δ 7.96 and 6.81 are assigned
to the methylene group (NHCH2). The IR spectrum of 12a
shows characteristic bands at 3176 and 2143 cm−1, assigned to
ν(NH) and ν(NC), respectively. The FAB mass spectrum
displays a parent peak at m/z 510.1 (M+). A few metal
complexes containing a methyleneimine moiety (NHCH2)
have been synthesized by the reaction of a methylhydrazine or
methylimido complex.38
6893
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
Figure 8. ORTEP drawing of 12b with thermal ellipsoids shown at the
50% probability level. Selected distances [Å] and angles [deg]:
Ru(1)−N(1) 2.132(5), Ru(1)−N(3) 2.127(5), Ru(1)−N(5)
2.083(5), Ru(1)−N(9) 2.055(5), N(9)−C(20) 1.272(9); Ru(1)−
N(9)−C(20) 130.3(5), N(9)−C(20)−C(21) 126.5(8), Ru(1)−
C(15)−N(8) 170.2(7).
Figure 10. ORTEP drawing of 13 with thermal ellipsoids shown at the
50% probability level. Selected distances [Å] and angles [deg]:
Ru(1)−N(1) 2.137(9), Ru(1)−N(3) 2.036(10), Ru(1)−N(5)
2.132(10), Ru(1)−I(1) 2.7451(14); C(10)−Ru(1)−I(1) 86.8(4).
benzene to afford exclusively the 1,5-disubstituted-1,2,3-
triazoles.41 On the other hand, we have reported the first
example of dimerization of alkynes with the ruthenium azido
complex instead of ruthenium chloride complex to give (E)-
enynes carried out in organic and aqueous media.24 Therefore,
a ruthenium azido complex was a logical choice in our search
for a new catalyst of the click reaction. We have initially
investigated the reaction of phenylacetylene with benzyl azide
in the presence of ruthenium azido complex 2. A mixture of
benzyl azide and phenylacetylene (1:1.2 equiv, respectively) in
toluene was heated at 80 °C for 24 h in the presence of 2% mol
of 2 to afford the 1,5-disubstituted-1,2,3-triazoles (14a) in high
yields (Table 1). The resulting reaction mixture was then
1
1
analyzed by H NMR. In the H NMR spectrum of 14a, two
singlet resonances appear at δ 5.56 and 7.73, attributed to
CH2Ph and CH, respectively. In contrast, reaction could afford
the 1,5-disubstituted-1,2,3-triazoles (14b, 61.8% yield) and
small amounts of 1,5-disubstituted-1,2,3-triazoles (14a, 17.3%
Table 1. Preparation of 1,4,5-Trisubstituted-1,2,3-triazoles
via Ru-Catalyzed Cycloadditions of Benzyl Azide with
Alkynes
entry
R1
R2
solvent
yield (%)
1
2
3
4
5
6
7
8
9
Ph
H
H
H
H
H
H
H
H
Ph
toluene
water
74
73
82
77
85
81
72
71
80
Figure 9. ORTEP drawing of 12c with thermal ellipsoids shown at the
50% probability level. Selected distances [Å] and angles [deg]:
Ru(1)−N(1) 2.088(6), Ru(1)−N(3) 2.103(6), Ru(1)−N(5)
2.115(6), Ru(1)−N(9) 2.048(6), N(9)−C(20) 1.288(9); Ru(1)−
N(9)−C(20) 127.0 (5), N(9)−C(20)−C(21) 128.9(7), Ru(1)−
C(15)−N(8) 170.2(8).
Ph
nBu
nBu
tBu
tBu
toluene
water
toluene
water
C(O)OMe
(CH3)3Si
Ph
toluene
toluene
toluene
Cp*(PPh3)2RuCl was reported to catalyze the cycloaddition
reaction of terminal alkynes with alkyl azides in refluxing
6894
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
yield) in the absence of catalyst 2. To our knowledge, this is the
first example of a ruthenium azido complex catalyzing the
cycloaddition reaction of terminal alkynes with alkyl azides.
Since complex 2 has some solubility in polar solvents, the click
reactions were attempted in water. Chemical reactions in
aqueous media are of growing importance because of many
potential advantages, such as alleviation of environmental
problems associated with the use of organic solvents.42
Surprisingly, phenylacetylene could be coupled with benzyl
azide in water with regioselectivity essentially identical with that
observed in organic media
substitution reaction rather than a [3+2] cycloaddition with 2
in the presence of H2O to produce carbonyl complexes via the
vinylidene intermediates. Interestingly, reaction of 2 with H-
CC-CMe2OH in MeOH gives the cationic Fischer carbene
complex. In contrast, reaction of H-CC-CH2CH2OH with 2
gives rise to the five-membered cyclic oxycarbene complex.
Several cationic imine complexes are formed by the reaction of
RCH2X with 2. Preliminary results on the catalytic activity of 2
are also presented. Complex 2 catalyzes cycloaddition of
alkynes and organic azides to give the 1,5-disubstituted
triazoles.
To evaluate the scope of this new ruthenium-catalyzed
process with respect to the alkyne component, reactions of
benzyl azide with several alkynes were carried out. Complete
consumption of the benzyl azide at the end of the reaction was
confirmed by 1H NMR analysis of the final reaction mixture. A
selection of examples is presented in Table 1. Thus, both
terminal and internal alkynes reacted with benzyl azide to give
the corresponding triazoles. A detailed mechanism for the click
reactions mediated by the 2 system is not yet clear, as the
intermediates of the click reactions have not been identified. It
has been established that click reactions mediated by the very
similar precursor Cp*(PPh3)2RuCl proceed through the
coupling of an alkyne and an azide ligand.41 It is very likely
that the present formation of triazoles may involve a similar
mechanism (Scheme 6). That is, oxidative coupling of an
EXPERIMENTAL SECTION
■
General Procedures. All manipulations were performed under
nitrogen using vacuum-line, drybox, and standard Schlenk techniques.
CH3CN and CH2Cl2 were distilled from CaH2 and diethyl ether, and
THF was distilled from Na/ketyl. All other solvents and reagents were
of reagent grade and were used without further purification. NMR
spectra were recorded on Bruker AC-200 and AM-300WB FT-NMR
spectrometers at room temperature (unless stated otherwise) and are
reported in δ units with residual protons in the solvent as an internal
standard (CDCl3, δ 7.24; CD3CN, δ 1.93; C2D6CO, δ 2.04). FAB
mass spectra were recorded on a JEOL SX-102A spectrometer.
Tp(PPh3)2RuCl43 was prepared by following the method reported in
the literature. Elemental analyses and X-ray diffraction studies were
carried out at the Regional Center of Analytical Instrument at National
Taiwan University.
Preparation of Tp(PPh3)(tBuNC)Ru-Cl (1). To a Schlenk flask
charged with complex Tp(PPh3)2RuCl (0.15 g, 0.17 mmol) in 20 mL
of CH2Cl2 was added tBuNC (0.20 mL, 1.77 mmol). The solution was
stirred for 24 h, the color changed from yellow to bright yellow, and
then the solution was filtered through Celite. Solvent of the filtrate was
removed under vacuum, and the residue was washed with n-hexane to
give 1 (0.07 g, 59% yield). Spectroscopic data for 1: IR (KBr, cm−1):
ν(B−H) 2471 (br), ν(NC) 2141 (s). 1H NMR (CDCl3): δ 8.00 (d,
JH−H = 2.2 Hz, 1H, Tp), 7.63 (d, JH−H = 2.2 Hz, 1H, Tp), 7.58 (d, JH−H
= 2.2 Hz, 1H, Tp), 7.55 (d, JH−H = 2.2 Hz, 1H, Tp), 7.41−7.21 (m,
Ph), 6.84 (1H, Tp), 6.21 (1H, Tp), 6.16 (t, JH−H = 2.2 Hz, 1H, Tp),
5.84 (t, JH−H = 2.2 Hz, 1H, Tp), 5.67 (t, JH−H = 2.2 Hz, 1H, Tp), 1.40
(s, 9H, CMe3). 13C NMR (CDCl3): δ 152.4 (d, JP−C = 21.9 Hz,
CNCMe3), 149.7−104.2 (m, PPh3, Tp), 58.7 (CMe3), 32.1 (CMe3).
31P NMR (CDCl3): δ 50.3. MS (FAB) m/z: 695.1 (M+), 660.1 (M+ −
Scheme 6
t
Cl), 577.1 (M+ − BuNC, Cl). Anal. Calcd for C32H34BClN7PRu: C,
55.30; H, 4.93; N, 14.11. Found: C, 55.26; H, 4.89; N, 14.15.
Preparation of Tp(PPh3)(tBuNC)Ru-N3 (2). To a solution of 1
(0.20 g, 0.29 mmol) in 50 mL of MeOH was added excess NaN3 (0.20
g, 3.00 mmol), and the solution was heated to reflux for 24 h. Yellow
precipitates formed and, after cooling, were filtered off and washed
with CH2Cl2 and n-hexane. This yellow, solid product was dried under
vacuum to give compound 2 (2.02 g, 99% yield). Spectroscopic data
for 2: IR (KBr, cm−1): ν(B−H) 2469 (br), ν(NC) 2146 (s), ν(N3)
2052 (vs). 1H NMR (CDCl3): δ 8.01 (d, JH−H = 2.1 Hz, 1H, Tp), 7.64
(d, JH−H = 2.1 Hz, 2H, Tp), 7.62 (d, JH−H = 2.1 Hz, 1H, Tp), 7.32
−7.15 (m, Ph), 6.77 (1H, Tp), 6.52 (1H, Tp), 6.21(t, JH−H = 2.1 Hz,
1H, Tp), 5.85 (t, JH−H = 2.1 Hz, 1H, Tp), 5.77 (t, JH−H = 2.1 Hz, 1H,
Tp), 1.41 (s, 9H, CMe3). 13C NMR (CDCl3): δ 156.1 (d, JP−C = 21.6
Hz, CNCMe3), 145.7 −105.6 (m, PPh3, Tp), 57.9 (CMe3), 32.0
(CMe3). 31P NMR (CDCl3): δ 51.4. MS (FAB) m/z: 702.2 (M+),
alkyne and an azide on ruthenium may initially give a six-
membered ruthenacycle, which then undergoes reductive
elimination, releasing the aromatic triazole product. However,
unlike Cp*(PPh3)2RuCl, click reactions by the complex 2 were
carried in protic solvents such as H2O. At present, the
mechanism of the click reactions can only be speculated upon.
Further work is in progress and will be reported in a
forthcoming paper.
Concluding Remarks. The reaction of ruthenium azido
complex Tp(tBuNC)(PPh3)Ru-N3 (2) and alkynes with
electron-withdrawing substituents yielded a series of triazolato
complexes via a [3+2] cycloaddition of a CC bond with the
azido group. Other reagents also react with 2, but the products
do not result from 1,3-dipolar cycloadditions. Significantly,
terminal alkynes behave as C−H acids and undergo a ligand
t
t
619.3 (M+ − BuNC), 577.1 (M+ − BuNC, N3). Anal. Calcd for
C32H34BN10PRu: C, 54.79; H, 4.89; N, 19.97. Found: C, 54.56; H,
4.86; N, 19.90.
Synthesis of N(2)-Bound Tp(PPh3)(tBuNC)Ru-N3C2(CO2Me)2
(3a). To a Schlenk flask charged with 2 (0.10 g, 0.14 mmol) were
added dimethyl acetylene dicarboxylate (234 mg, 1.65 mmol) and 20
mL of CH2Cl2. The mixture was stirred at room temperature for 3 h.
Then the solvent was reduced to 2 mL under vacuum. To the residue
was added 20 mL of n-hexane, giving a yellow precipitate. After
filtration, the precipitate was washed with 4 × 5 mL of n-hexane and
6895
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
dried under vacuum to give the N(2)-bound Tp(PPh3)(tBuNC)Ru-
N3C2(CO2Me)2 (3a) (0.11 g, 93% yield). Spectroscopic data for 3a
are as follows: IR (KBr, cm−1): ν(B−H) 2463 (br), ν(NC) 2141
Reaction of 2 with CS2. A Schlenk flask was charged with CS2
(0.7 mL, 0.25 mmol) and 2 (0.10 g, 0.14 mmol) in 20 mL of CH2Cl2.
The mixture was stirred at room temperature for 72 h. Then the
resulting brown solution was dried in vacuo. The residue was extracted
with hexane, and the residual solid was further washed with diethyl
ether to give the complex Tp(PPh3)(tBuNC)Ru-NCS (6) (0.088 g,
87% yield). The hexane extract was concentrated and then eluted with
CH2Cl2 on a silica gel-packed column to give Tp(tBuNC)2Ru-NCS
(7) (0.005 g, 6% yield). Spectroscopic data for 6 are as follows: IR
(KBr, cm−1): ν(B−H) 2461 (br), ν(NC) 2168 (s), ν(NCS) 2119
(s). 1H NMR (CDCl3): δ 7.79 (d, JH−H = 2.0 Hz, 2H, Tp), 7.61−7.08
(m, Ph, Tp), 6.59 (br, 1H, Tp), 6.49 (br, 1H, Tp), 6.18 (br, 1H, Tp),
6.08 (t, JH−H = 2.1 Hz, 1H, Tp), 5.83 (t, JH−H = 2.0 Hz, 1H, Tp), 5.73
(t, 1H, J H−H = 2.0 Hz, Tp), 1.49 (s, 9H, CMe3). 31P NMR (CDCl3): δ
43.9. 13C NMR (CDCl3): δ 157.2 (NCS), 151.6 (d, JP−C = 21.4 Hz,
CNCMe3), 144.8 −105.1 (m, PPh3, Tp), 54.6 (CMe3), 33.0 (CMe3).
1
(s), ν(CO) 1736 (vs), ν(NN) 1433 (s) ν(C−O) 1241 (m). H
NMR (CDCl3): δ 7.64 (d, JH−H = 1.9 Hz, 1H, Tp), 7.51 (d, JH−H = 1.9
Hz, 1H, Tp), 7.38 (d, JH−H = 2.0 Hz, 1H, Tp), 7.27−6.85 (m, Tp, Ph),
6.54 (d, JH−H = 1.9 Hz, 1H, Tp), 6.01 (d, JH−H = 2.0 Hz, 1H, Tp), 5.89
(d, JH−H = 2.0 Hz, 1H, Tp), 5.81 (t, JH−H = 2.0 Hz, 1H, Tp), 5.61 (t,
JH−H = 2.0 Hz, 1H, Tp), 3.77 (s, 6H, OCH3), 1.43 (s, 9H, CMe3). 13
C
NMR (CDCl3): δ 164.1 (CO2), 156.1 (d, JP−C = 21.3 Hz, CNCMe3),
140.2 (C(CO2CH3)2), 141.5 −106.3 (m, PPh3, Tp), 55.3 (CMe3),
52.4 (OCH3), 33.4 (CMe3). 31P NMR (CDCl3): δ 52.9. MS (FAB) m/
z: 844.2 (M+), 761.3 (M+
− −
tBuNC), 577.1 (M+ tBuNC,
N3C2(CO2Me)2). Anal. Calcd for C38H40BN10O4PRu: C, 54.10; H,
4.78; N, 16.60. Found: C, 54.03; H, 4.69; N, 16.55.
The complex N(2)-bound Tp(PPh 3 )(t BuNC)Ru-
N3C2(CO2CH2CH3)2 (3b) (0.09 g, 74% yield from 0.10 g of 2)
was prepared by using a similar procedure to that of 3a. Spectroscopic
data for 3b are as follows: IR (KBr, cm−1): ν(B−H) 2466 (br), ν(N
C) 2144 (s), ν(CO) 1735 (vs), ν(NN) 1434 (s) ν(C−O) 1243
MS (FAB) m/z: 718.1 (M+), 660.1 (M+ − NCS), 635.2 (M+
−
tBuNC). Anal. Calcd for C33H34BN8PRuS: C, 55.23; H, 4.78; N, 15.62.
Found: C, 55.21; H, 4.71; N, 15.56. Spectroscopic data for 7 are as
follows: IR (KBr, cm−1): ν(B−H) 2459 (br), ν(NC) 2164 (s),
1
1
(m). H NMR (CDCl3): δ 7.92 (d, JH−H = 2.0 Hz, 1H, Tp), 7.85 (d,
ν(NCS) 2114 (s). H NMR (CDCl3): δ 7.91 (d, JH−H = 2.0 Hz, 2H,
JH−H = 2.1 Hz, 1H, Tp), 7.75 (d, JH−H = 2.0 Hz, 1H, Tp), 7.37−6.99
(m, Tp, Ph), 6.88 (d, JH−H = 1.9 Hz, 1H, Tp), 5.91 (d, JH−H = 2.0 Hz,
1H, Tp), 5.77 (d, JH−H = 2.0 Hz, 1H, Tp), 5.70 (t, JH−H = 2.0 Hz, 1H,
Tp), 5.60 (t, JH−H = 2.0 Hz, 1H, Tp), 4.21 (q, JH−H = 7.2 Hz, 4H,
OCH2), 1.44 (s, 9H, CMe3), 1.18 (q, JH−H = 7.2 Hz, 6H, OCH2CH3).
13C NMR (CDCl3): δ 162.8 (CO2), 154.3 (d, JP−C = 20.9 Hz,
CNCMe3), 144.1 (C(CO2CH2CH3)2), 136.3−110.3 (m, Tp, PPh3),
60.7 (OCH2), 56.5 (CMe3), 35.4 (CMe3). 14.6 (OCH2CH3). 31P
NMR (CDCl3): δ 52.7. MS (FAB) m/z: 872.2 (M+), 789.1 (M+ −
tBuNC), 577.1 (M+ − tBuNC, N3C2(CO2CH2CH3)2). Anal. Calcd for
C40H44BN10O4PRu: C, 55.11; H, 5.09; N, 16.07. Found: C, 55.03; H,
5.01; N, 15.99.
Tp), 6.59 (br, 2H, Tp), 6.46 (br, 1H, Tp), 6.168 (t, JH−H = 2.1 Hz, 2H,
Tp), 5.67 (t, JH−H = 2.0 Hz, 1H, Tp), 5.73 (t, 1H, JH−H = 2.0 Hz, Tp),
1.49 (s, 18H, CMe3). 13C NMR (CDCl3): δ 156.8 (NCS), 152.4 (d,
JP−C = 21.2 Hz, CNCMe3), 144.6 −106.2 (m, Tp), 52.4 (CMe3), 32.0
(CMe3). MS (FAB) m/z: 539.13 (M+), 480.1 (M+ − NCS), 456.1 (M+
t
− BuNC). Anal. Calcd for C320H28BN9PRuS: C, 44.61; H, 5.24; N,
23.41. Found: C, 44.41; H, 5.21; N, 23.36. An intermediate,
Tp(PPh3)(tBuNC)Ru-N3CS(S) (5), was observed if the reaction
was monitored by NMR spectroscopy within 20 min. Spectroscopic
data for 5: IR (KBr, cm−1): ν(B−H) 2452 (br), ν(NC) 2143 (s),
ν(CS) 1296 (s). 1H NMR (acetone): δ 7.98 (br, 1H, Tp), 7.84 (br,
1H, Tp), 7.78 (br, 1H, Tp), 7.48- 6.98 (m, Ph, Tp), 6.94 (br, 1H, Tp),
6.56 (br, 1H, Tp), 6.14 (br, 1H, Tp), 6.01 (br, 1H, Tp), 5.81 (br, 1H,
Tp), 5.39 (br, 1H, Tp), 1.41 (s, 18H, CMe3). 31P NMR (acetone): δ
50.8. MS (FAB) m/z: 778.1 (M+), 660.1 (M+ − N3CS(S)), 635.1 (M+
Synthesis of Organic 1,4,5-Trisubstituted Triazoles. To a
solution of complex 3a (10 mg, 0.018 mmol) in CDCl3 prepared
under N2 in an NMR tube was added one drop (5 μL) of BrCH2CH3.
The reaction was carried out at 50 °C for 24 h, and the color changed
from bright yellow to orange. Then the solvent and excess BrCH2CH3
were removed under vacuum and washed with 1 mL of cold n-hexane.
After filtration, the orange precipitate was washed with 1 mL of n-
hexane and dried under vacuum to give the product Tp(PPh3)-
(tBuNC)Ru-Br (11.1 mg, 0.015 mmol, 83% yield). The filtrate was
dried and extracted with 4 × 5 mL of cold n-hexane. The extract was
filtered, and the filtrate was dried under vacuum to give a mixture of
the organic triazole N3(CH2CH3)C2(CO2Me)2 (4a). Spectroscopic
t
− BuNC).
Reaction of 2 with Phenylacetylene. To a distilled methanol
(20 mL) solution of 2 (0.14 g, 0.20 mmol) was added phenylacetylene
(0.14 mL, 1.3 mmol). The solution was heated to reflux for 6 h. Then
the resulting green solution was dried in vacuo. The residue was
extracted with hexane, and the residual solid was further washed with
diethyl ether to give the complex Tp(tBuNC)(OC)Ru-CH2Ph (8a)
(0.09 g, 87% yield). Spectroscopic data for 8a: IR (KBr, cm−1): ν(B−
1
H) 2455 (br), ν(NC) 2178 (s), ν(CO) 1949 (vs). H NMR
1
(CDCl3): δ 7.78 (d, JH−H = 1.9 Hz, 1H, Tp), 7.74 (d, JH−H = 2.1 Hz,
1H, Tp), 7.66 (d, JH−H = 2.0 Hz, 1H, Tp), 7.61 (d, JH−H = 2.0 Hz, 1H,
Tp), 7.28−6.90 (m, Tp, Ph), 6.29 (d, JH−H = 1.9 Hz, 1H, Tp), 6.22 (t,
JH−H = 2.0 Hz, 1H, Tp), 6.19 (t, JH−H = 2.0 Hz, 1H, Tp), 2.82 (d, JH−H
= 9.2 Hz, CHHPh), 2.40 (d, JH−H = 9.2 Hz, CHHPh), 1.29 (s, 9H,
CMe3), 1.18 (q, JH−H = 7.2 Hz, 6H, OCH2CH3). 13C NMR (CDCl3):
δ 204.7 (d, JP−C = 15.8 Hz, CO), 152.6 (d, JP−C = 21.9 Hz, CNCMe3),
141.3−118.3 (m, Tp, PPh3), 56.4 (CMe3), 36.2 (CMe3), 18.8 (d, JP−C
= 9.2 Hz, CH2). 31P NMR (CDCl3): δ 56.3. MS (FAB) m/z: 518.1
(M+), 427.1 (M+ − CH2Ph), 399.1 (M+ − CH2Ph, CO). Anal. Calcd
for C22H26BN7ORu: C, 51.17; H, 5.08; N, 18.99. Found: C, 51.03; H,
5.06; N, 18.99.
data for 4a are as follows: H NMR (CDCl3): δ 3.92 (s, 3H, CH3),
3.88 (s, 3H, CH3), 2.89 (q, 2H, CH2, JH−H = 7.5 Hz), 1.31 (t, 3H,
CH3, JH−H = 7.5 Hz). 13C NMR (CDCl3): δ 163.5 (CO2), 153.6
(CO2), 141.5 (C(CO2CH3)), 132.5 (C(CO2CH3)), 52.8 (OCH3),
52.1 (OCH3), 45.9 (CH2), 13.7 (CH3). MS (m/z): 214.1 (M+ + 1).
Complex N3(CH2Ph)C2(CO2Me)2 (4b) was prepared with a
similar procedure to that of 4a. Spectroscopic data for 4b are as
1
follows: H NMR (CDCl3): δ 7.84−7.13 (m, 5H, Ph), 5.74 (s, 2H,
CH2), 3.96 (s, 3H, CH3), 3.83 (s, 3H, CH3). 13C NMR (CDCl3): δ
161.5 (CO2), 159.3 (CO2), 141.4 (C(CO2CH3)), 136.5
(C(CO2CH3)), 135.8−126.7 (Ph), 53.9 (OCH3), 53.2 (CH2), 52.4
(OCH3). MS (m/z) 276.1 (M+ + 1).
Complex Tp(tBuNC)(OC)Ru-CH2(4-CH3Ph) (8b) was prepared
with a similar procedure to that of 8a. Spectroscopic data for 8b: IR
(KBr, cm−1): ν(B−H) 2454 (br), ν(NC) 2174 (s), ν(CO) 1943
Complex N3(CH2C6F5)C2(CO2Me)2 (4c) was prepared with a
similar procedure to that of 4a. Spectroscopic data for 4c are as
follows: 1H NMR (CDCl3): δ 5.88 (s, 2H, CH2), 3.96 (s, 3H, OCH3),
3.82 (s, 3H, OCH3). 13C NMR (CDCl3): δ 161.2 (CO2), 159.4
(CO2), 142.4 (C(CO2CH3)), 131.3 (C(CO2CH3)), 53.2 (CH2), 52.9
(OCH3), 52.3 (OCH3). MS (m/z): 366.1 (M+ + 1).
Complex N3(CH2CO2Me) C2(CO2Me)2 (4d) was prepared with a
similar procedure to that of 4a. Spectroscopic data for 4d are as
follows: 1H NMR (CDCl3): δ 5.41 (s, 2H, CH2), 3.95 (s, 3H, OCH3),
3.89 (s, 3H, OCH3). 13C NMR (CDCl3): δ 165.4(CO2), 163.2 (CO2),
158.3 (CO2), 144.1 (C(CO2CH3)), 132.8 (C(CO2CH3)), 53.2
(OCH3), 52.7 (OCH3), 52.3 (OCH3), 51.9 (CH2). MS (m/z):
285.1 (M+ + 1).
1
(vs). H NMR (CDCl3): δ 7.78 (d, 1H, JH−H = 1.9 Hz, Tp), 7.73 (d,
1H, JH−H = 1.9 Hz, Tp), 7.65 (d, 1H, JH−H = 2.3 Hz, Tp), 7.64 (d, 1H,
JH−H = 2.3 Hz, Tp), 7.59 (d, 1H, JH−H = 2.3 Hz, Tp), 7.48 (d, 1H, JH−H
= 1.8 Hz, Tp), 7.18−6.94 (m, 4H, Ph), 6.24 (t, 1H, JH−H = 1.9 Hz,
Tp), 6.20 (t, 1H, JH−H = 1.9 Hz, Tp), 6.12 (t, 1H, JH−H = 1.8 Hz, Tp),
2.78 (d, 1H, JH−H = 9.3 Hz, CHH), 2.37 (d, 1H, JH−H = 9.3 Hz, CHH),
2.29 (s, 3H, CH3C6H4), 1.27 (s, 9H, CMe3). 13C NMR (CDCl3): δ
205.6 (d, JP−C = 15.6 Hz, CO), 151.8 (d, JP−C = 21.8 Hz, CNCMe3),
140.6−116.6 (m, Tp, PPh3), 54.6 (CMe3), 36.4 (CMe3), 21.2
(CH3C6H4), 18.6 (d, JP−C = 9.4 Hz, CH2). MS (FAB) m/z: 532.1
6896
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
(M+), 427.1 (M+ − CH2(4-CH3Ph)), 399.1 (M+ − CH2(4-CH3Ph),
CO). Anal. Calcd for C23H29BN7ORu: C, 51.98; H, 5.50; N, 18.45.
Found: C, 51.95; H, 5.51; N, 18.39.
(M+ − PF6, C4H6O). Anal. Calcd for C36H40BF6N7OP2Ru: C, 49.44;
H, 4.61; N, 11.21. Found: C, 49.33; H, 4.55; N, 11.11.
Synthesis of [Tp(tBuNC)2Ru(NHCH2)]I (12a). Dichlorome-
thane (20 mL) was added to a round-bottomed flask charged with
complex 2 (0.1 g, 0.07 mmol) and CH3I (1 mL). The reaction mixture
was stirred at room temperature for 6 h. The solvent was evaporated
under reduced pressure to 5 mL. To the solution was added 20 mL of
n-hexane, whereupon a yellow compound was precipitated. The
precipitate was filtered, washed with 10 mL of n-hexane, and dried
under vacuum to yield [Tp(tBuNC)2Ru(NHCH2)]I (12a) (0.06 g,
48% yield). Spectroscopic data for 12a are as follows: IR (KBr, cm−1):
ν(N−H) 3176 (s), ν(B−H) 2465 (br), ν(NC) 2143 (m). 1H NMR
(CDCl3): δ 12.86 (dd, JH−H = 13 Hz, JH−H = 20 Hz, 1H, NH), 7.96 (d,
JH−H = 13 Hz, 1H, NCH), 7.78 (d, JH−H = 2.0 Hz, 1H, Tp), 7.71 (d,
JH−H = 1.9 Hz, 1H, Tp), 6.81 (d, JH−H = 20 Hz, 1H, NCH), 6.47
(1H, Tp), 6.21 (1H, Tp), 5.96 (t, JH−H =2.2 Hz, 1H, Tp), 5.81 (t, JH−H
= 2.2 Hz, 1H, Tp), 1.41 (s, 18H, CMe3). 13C NMR (CDCl3): δ 169.9
(NC), 149.6 (d, JP−C = 20.1 Hz, CNCMe3), 142.1−129.3 (m, Tp),
52.8 (CMe3), 33.6 (CMe3). MS (FAB) m/z: 510.1 (M+ − I), 427.1
(M+ − I − tBuNC), 398.1 (M+ − I, tBuNC, NHCH2). Anal. Calcd
for C20H31BIN9Ru: C, 37.75; H, 4.91; N, 19.81. Found: C, 37.67; H,
4.79; N, 19.67.
Synthesis of Tp(tBuNC)(OC)Ru-C(H)CH2 (9). To a distilled
methanol (20 mL) solution of 2 (0.14 g, 0.20 mmol) was added
progargyl alcohol (0.20 mL, 3.57 mmol). The solution was stirred for
6 h, the color changed from yellow to green, and the resulting green
solution was dried in vacuo. The residue was extracted with hexane,
and the residual solid was further washed with diethyl ether to give the
complex Tp(tBuNC)(OC)Ru-C(H)CH2 (9) (0.8 g, 88% yield).
Spectroscopic data for 9: IR (KBr, cm−1): ν(B−H) 2449 (br), ν(N
C) 2169 (s), ν(CO) 1951 (vs). 1H NMR (CDCl3): δ 8.01 (d, JH−H
= 2.0 Hz, 1H, Tp), 7.78 (d, JH−H = 2.0 Hz, 1H, Tp), 7.68 (d, JH−H
=
2.0 Hz, 1H, Tp), 7.55 (d, JH−H = 2.1 Hz, 1H, Tp), 7.29−6.99 (m, Tp,
Ph), 6.33 (d, JH−H = 1.9 Hz, 1H, Tp), 6.21 (t, JH−H = 2.0 Hz, 1H, Tp),
6.11 (t, JH−H = 2.0 Hz, 1H, Tp), 5.46, 5.54 (mx2, 3H, CHCH2), 1.39
(s, 9H, CMe3). 13C NMR (CDCl3): δ 204.6 (d, JP−C = 15.9 Hz, CO),
150.0 (d, JP−C = 21.7 Hz, CNCMe3), 153.1 (br, HC), 144.3−111.5
(m, Tp, PPh3), 107.1 (CH2), 54.1 (CMe3), 34.8 (CMe3). MS (FAB)
m/z: 454.1 (M+), 427.1 (M+ − HCCH2), 399.1 (M+ − HCCH2,
CO). Anal. Calcd for C15H20BN7ORu: C, 42.27; H, 4.73; N, 23.00.
Found: C, 42.13; H, 4.63; N, 22.78.
Complex [Tp(tBuNC)2Ru(NHCH(CH3))]I (12b) (0.04 g, 0.13
mmol, 47% yield from 0.20 g of 2) was similarly prepared from
ICH2CH3. Spectroscopic data of 12b: IR (KBr, cm−1): ν(N−H) 3184
Synthesis of {Tp(tBuNC)(PPh3)RuC(OMe)C(Me)2}(PF6)
(10). To a CH2Cl2 solution (20 mL) of the solution of 2 (0.14 g,
0.20 mmol) were added successively NH4PF6 (0.10 g, 0.60 mmol) and
then 2-methyl-3-butyn-2-ol (0.3 mL, 3.10 mmol), and the reaction
mixture was stirred for 6 h. The solvent was evaporated under reduced
pressure to 5 mL. To the solution was added 20 mL of n-hexane,
whereupon a yellow compound was precipitated. The precipitate was
filtered, washed with 10 mL of n-hexane and ether, and then dried
under vacuum to yield the complex {Tp(tBuNC)(PPh3)Ru
C(OMe)C(Me)2}(PF6) (10) (0.13 g, 72%). Spectroscopic data
for 10: IR (KBr, cm−1): ν(B−H) 2447 (br), ν(NC) 2173 (s),
ν(CO) 1967 (vs), ν(CC) 1587 (vs), 1283 (s, C−O), 850 (s,
1
(s), ν(B−H) 2461 (br), ν(NC) 2144 (m). H NMR (CDCl3): δ
11.47 (d, JH−H = 21 Hz, 1H, NH), 7.86 (d, JH−H = 2.0 Hz, 1H, Tp),
7.63 (d, JH−H = 2.1 Hz, 1H, Tp), 7.58 (d, JH−H = 1.9 Hz, 1H, Tp), 6.95
(1H, Tp), 6.87 (d, JH−H = 20 Hz, 1H, NCH), 6.73 (1H, Tp), 6.68
(1H, Tp), 6.43 (t, JH−H = 2.1 Hz, 1H, Tp), 5.96 (t, JH−H = 2.2 Hz, 1H,
Tp), 5.84 (t, JH−H = 2.2 Hz, 1H, Tp), 2.15 (NCHCH3), 1.42 (s,
18H, CMe3). 13C NMR (CDCl3): δ 170.2 (NC), 151.3 (d, JP−C
=
20.4 Hz, CNCMe3), 143.1−117.2 (m, Tp), 52.5 (CMe3), 31.6 (CMe3),
22.8 (NCHCH3). MS (FAB) m/z: 524.2 (M+ − Br), 441.1 (M+ −
Br − tBuNC), 398.1 (M+ − Br − tBuNC, NHCHCH3). Anal. Calcd
for C21H33BBrN9Ru: C, 41.81; H, 5.51; N, 20.89. Found: C, 41.80; H,
5.47; N, 20.86.
−
PF6 ). 1H NMR (CDCl3): δ 8.02 (d, JH−H = 2.1 Hz, 1H, Tp), 7.65 (d,
JH−H = 2.1 Hz, 1H, Tp), 7.54 (d, JH−H = 2.0 Hz, 1H, Tp), 7.49 (d, JH−H
= 2.0 Hz, 1H, Tp), 7.21−6.91 (m, Tp, Ph), 6.81 (s, 1H, HCCMe2),
6.31 (d, JH−H = 2.0 Hz, 1H, Tp), 6.18 (t, JH−H = 2.0 Hz, 1H, Tp), 6.09
(t, JH−H = 2.0 Hz, 1H, Tp), 4.65 (s, 3H, OMe), 2.14 (s, 3H, CMe),
1.92 (s, 3H, CMe), 1.41 (s, 9H, CMe3). 13C NMR (CDCl3): δ 312.2
(d, JP−C = 13.6 Hz, RuC), 153.6 (d, JP−C = 21.1 Hz, CNCMe3),
153.7 (s, HC), 138.1 (s, CMe2), 136.2−106.5 (m, Tp, PPh3),
68.2 (OMe), 54.7 (CMe3), 33.8 (CMe3), 28.6 (CMe), 23.1 (
CMe). 31P NMR (CDCl3): δ 48.4. MS (FAB) m/z: 758.1 (M+ − PF6),
Complex [Tp(tBuNC)2Ru(NHCHPh]Br (12c) (0.038 g, 0.15
mmol, 39% yield from 0.20 g of 2) was similarly prepared from
BrCH2Ph. Spectroscopic data of 12c: IR (KBr, cm−1): ν(N−H) 3176
1
(s), ν(B−H) 2464 (br), ν(NC) 2143 (m). H NMR (CDCl3): δ
12.36 (d, JH−H = 20.3 Hz, 1H, NH), 8.05 (d, JH−H = 2.1 Hz, 1H, Tp),
7.89 (d, JH−H = 2.0 Hz, 1H, Tp), 7.82 (d, JH−H = 1.9 Hz, 1H, Tp), 6.94
(1H, Tp), 6.89 (d, JH−H = 20 Hz, 1H, NCH), 6.68 (1H, Tp), 6.56
(1H, Tp), 6.41 (t, JH−H = 2.0 Hz, 1H, Tp), 5.91 (t, JH−H = 2.1 Hz, 1H,
Tp), 5.80 (t, JH−H = 2.0 Hz, 1H, Tp, 1.42 (s, 18H, CMe3). 13C NMR
(CDCl3): δ 171.8 (NC), 149.9 (d, JP−C = 21.0 Hz, CNCMe3),
141.4−124.6 (m, Tp), 53.8 (CMe3), 31.6 (CMe3). MS (FAB) m/z:
660.1 (M+
−
PF6, C(OMe)C(Me)2). Anal. Calcd for
C38H44BF6N7OP2Ru: C, 50.56; H, 4.91; N, 10.86. Found: C, 60.53;
H, 4.78; N, 10.79.
Synthesis of {Tp(tBuNC)(PPh3)RuC4H6O}(PF6) (11). A
mixture of 2 (0.14 g, 0.20 mmol), NH4PF6 (0.10 g, 0.60 mmol),
and 3-butyn-1-ol (0.3 mL, 3.96 mmol) in CH2Cl2 (20 mL) was stirred
at room temperature for 24 h. The solvent was evaporated under
reduced pressure to 5 mL. To the solution was added 20 mL of n-
hexane, whereupon a yellow compound was precipitated. The
precipitate was filtered, washed with 10 mL of n-hexane and ether,
and then dried under vacuum to yield the complex {Tp(tBuNC)-
(PPh3)RuC4H6O}(PF6) (11) (0.14 g, 80%). Spectroscopic data for
11: IR (KBr, cm−1): ν(B−H) 2461 (br), ν(NC) 2169 (s), ν(CO)
t
586.1 (M+ − Br), 503.1 (M+ − Br − BuNC), 398.1 (M+ − Br −
tBuNC, NHCHPh). Anal. Calcd for C26H35BBrN9Ru: C, 46.93; H,
5.30; N, 18.95. Found: C, 46.76; H, 5.25; N, 18.76.
Synthesis of Tp(tBuNC)2RuI (13). Dichloromethane (20 mL) was
added to a round-bottomed flask charged with complex 2 (0.10 g, 0.07
mmol) and CH3I (1 mL). The reaction mixture was stirred at 35 °C
for 24 h. The solution was filtered through Celite. Solvent of the
filtrate was removed under vacuum, and the residue was washed with
n-hexane to give Tp(tBuNC)2RuI (13) (0.04 g, 94% yield).
1
Spectroscopic data for 13 are as follows: H NMR (CDCl3): δ 8.01
−
1961 (vs), 851 (s, PF6 ). 1H NMR (CDCl3): δ 7.93 (d, JH−H = 2.0 Hz,
(d, JH−H = 2.0 Hz, 1H, Tp), 7.74 (d, JH−H = 2.0 Hz, 1H, Tp), 7.68 (d,
JH−H = 1.8 Hz, 1H, Tp), 6.78 (d, JH−H = 2.0 Hz, 1H, Tp), 6.47 (1H,
Tp), 6.11 (1H, Tp), 5.90 (t, JH−H = 2.1 Hz, 1H, Tp), 5.80 (t, JH−H =2.1
Hz, 1H, Tp), 1.42 (s, 18H, CMe3).
General Procedure for 2-Catalyzed Cycloadditions. A mixture
of benzyl azide (0.50 mmol), alkyne R1-CC-R2 (0.60 mmol), and 2
(2 mol %) in 10 mL of solvent was heated at 80 °C for 24 h. The
progress of the reaction was monitored by 1H NMR. In most cases the
benzyl azide was completely consumed at the end of the reaction. The
solvent was removed under vacuum, and the product was purified by
silica gel chromatography. The unreacted alkyne and traces of side
products were first eluted out with hexane, followed by 1:1 hexane/
1H, Tp), 7.78 (d, JH−H = 2.0 Hz, 1H, Tp), 7.67 (d, JH−H = 2.0 Hz, 1H,
Tp), 7.48 (d, JH−H = 2.0 Hz, 1H, Tp), 7.24−6.41 (m, Tp, Ph), 6.32 (d,
JH−H = 2.0 Hz, 1H, Tp), 6.11 (t, JH−H = 2.0 Hz, 1H, Tp), 6.02 (t, JH−H
= 2.0 Hz, 1H, Tp), 5.07−4.99 (m, 1H, RuC-CH2), 4.65−4.57 (m,
1H, RuC-CH2), 3.24−3.15 (m, 1H, RuC-OCH2), 2.90−2.79 (m,
1H, RuC-OCH2), 2.12−2.07 (m, 1H, RuC-CH2CH2), 1.89−1.82
(m, 1H, RuC-CH2CH2), 1.39 (s, 9H, CMe3). 13C NMR (CDCl3): δ
316.1 (d, JP−C = 14.1 Hz, RuC), 151.7 (d, JP−C = 20.1 Hz,
CNCMe3), 141.2−107.54 (m, Tp, PPh3), 83.6 (RuC-CH2), 54.6
(RuC-OCH2), 53.9 (CMe3), 34.1 (CMe3), 22.6 (RuC-CH2CH2).
31P NMR (CDCl3): δ 48.2. MS (FAB) m/z: 730.1 (M+ − PF6), 660.1
6897
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
ether. The pure 1,5-disubstututed triazole product was then obtained
by elution with ether.
REFERENCES
■
(1) (a) Nomiya, K.; Noguchi, R.; Oda, M. Inorg. Chim. Acta 2000,
298, 24. (b) Singh, H.; Chawla, A. S.; Kapoor, V. K.; Paul, D.;
Malhotra, R. Prog. Med. Chem. 1980, 17, 151. (c) Fan, W. Q.;
Katritzky, A. R. In Comprehensive Heterocyclic Chemistry II; Katritzky,
A. R.; Rees, C. W.; Scriven, E. F. V., Eds.; Pergamon Press: Oxford,
U.K., 1996; Vol. 4, pp 1−126. (d) Herr, R. J. Bioorg. Med. Chem. 2002,
10, 3379. (e) Truica-Marasescu, F.; Wertheimer, M. R. Plasma Process.
Polym. 2008, 5, 44. (f) Katritzky, A. R.; Rees, C. W. Comprehensive
Heterocyclic Chemistry; Pergamon Press: Elmsford, NY, 1984; Vol. 5,
Part 4A, pp 791−838.
For 1-benzyl-5-phenyl-1H-1,2,3-triazole (14a, R1 = Ph, R2 = H): 1H
NMR (CDCl3): δ 7.72 (s, 1H), 7.36−7.26 (m, 8H), 7.01 (t, 2H, JH−H
= 3.6 Hz), 5.52 (s, 2H). 13C NMR (CDCl3): δ 138.36, 135.56, 133.31,
133.25, 129.61, 129.08, 128.91, 128.21, 127.21, 126.93, 51.85. EI-MS:
m/z 236 [M + 1].
For 1-benzyl-4-phenyl-1H-1,2,3-triazole (14b, R1 = Ph, R2 = H): 1H
NMR (CDCl3): δ 7.99 (s, 1H), 7.36−7.27 (m, 8H), 5.55 (s, 2H). 13
C
NMR (CDCl3): δ 161.12, 140.33, 133.61, 129.38, 129.21, 128.11,
127.35, 54.49, 52.21. EI-MS: m/z 236 [M + 1].
n
1
For 1-benzyl-5-butyl-1H-1,2,3-triazole (15, R1 = Bu, R2 = H): H
NMR (CDCl3): δ 7.38 (s, 1H), 7.26−7.17 (m, 3H), 7.08 (t, 2H, JH−H
= 3.8 Hz), 5.42 (s, 2H), 2.42 (t, 2H, JH−H = 7.8 Hz), 1.46−1.37 (m,
2H), 1.27−1.15 (m, 2H), 0.77 (t, 3H, JH−H = 7.2 Hz). 13C NMR
(CDCl3): δ 138.01, 135.59, 133.06, 133.01, 129.46, 128.78, 127.62,
52.13, 30.42, 23.35, 22.69, 14.16. EI-MS: m/z 216 [M + 1].
For 1-benzyl-5-(tert-butyl)-1H-1,2,3-triazole (16, R1 = tBu, R2 = H):
1H NMR (CDCl3): δ 7.11 (s, 1H), 7.03−6.84 (m, 3H), 6.75 (d, 2H,
JH−H = 7.0 Hz), 5.41 (s, 2H), 0.97 (s, 9H). 13C NMR (CDCl3): δ
146.03, 136.31, 131.32, 131.23, 128.57, 127.62, 126.29, 52.62, 29.93,
29.71. EI-MS: m/z 216 [M + 1].
(2) Szocs, E.; Bako, I.; Kosztolanyi, T.; Bertoti, I.; Kalman, E.
Electrochim. Acta 2004, 49, 1371.
́
(3) (a) Klapotke, T. M.; Mayer, P.; Sabate, C. M.; Welch, J. M.;
̈
̈
Wiegand, N. Inorg. Chem. 2008, 47, 6014. (b) KlapOotke, T. M.;
Stierstorfer, J. J. Am. Chem. Soc. 2009, 131, 1122. (c) Klapotke, T. M.;
̈
́
Sabate, C. M.; Welch, J. M. Eur. J. Inorg. Chem. 2009, 769. (d) Tao, G.-
H.; Twamley, B.; Shreeve, J. M. Inorg. Chem. 2009, 48, 9918.
(e) Singh, R. P.; Verma, R. D.; Meshri, D. T.; Shreeve, J. M. Angew.
Chem., Int. Ed. 2006, 45, 3584. (f) Tappan, B. C.; Huynh, M. H.;
Hiskey, M. A.; Chavez, D. E.; Luther, E. P.; Mang, J. T.; Son, S. F. J.
Am. Chem. Soc. 2006, 128, 6589. (g) Poturovic, S.; Lu, D.; Heeg, M. J.;
Winter, C. H. Polyhedron 2008, 27, 3280.
For 1-benzyl-5-(methoxycarbonyl)-1H-1,2,3-triazole (17, R1
=
1
C(O)OMe, R2 = H): H NMR (CDCl3): δ 7.96 (s, 1H), 7.31−7.26
(m, 5H), 5.58 (s, 2H), 3.84 (s, 3H). 13C NMR (CDCl3): δ 161.2,
139.30, 133.60, 129.82, 129.31, 128.34, 127.3, 54.50, 52.21. EI-MS: m/
z 218 [M + 1].
(4) (a) Huisgen, R. Proc. Chem. Soc. 1961, 357. (b) Huisgen, R.
Angew. Chem., Int. Ed. Engl. 1963, 2, 565. (c) Huisgen, R. Angew.
Chem., Int. Ed. Engl. 1963, 2, 633. (d) Huisgen, R. J. Org. Chem. 1976,
41, 403.
For 1-benzyl-5-(trimethylsilyl)-1H-1,2,3-triazole (18, R1
=
(5) Fruhauf, H. W. Chem. Rev. 1997, 97, 523.
1
(CH3)3Si, R2 = H): H NMR (CDCl3): δ 7.38−7.50 (m, 5H), 5.61
(d, 2H), 0.12 (s, 9H). 13C NMR (CDCl3): δ 136.13, 130.20, 129.41,
129.54, 54.61, 0.02. EI-MS: m/z 232 [M + 1].
(6) (a) Treichel, P. M.; Knebel, W. J.; Hess, R. W. J. Am. Chem. Soc.
1971, 93, 5424. (b) Beck, W.; Burger, K.; Fehlhammer, W. P. Chem.
Ber. 1971, 104, 1816. (c) Fehlhammer, W. P.; Dahl, L. F. J. Am. Chem.
Soc. 1972, 94, 3370. (d) Fehlhammer, W. P.; Kemmerich, T.; Beck, W.
Chem. Ber. 1979, 112, 468.
For 1-benzyl-4,5-diphenyl-1H-1,2,3-triazole (19, R1 = Ph, R2 = Ph):
1H NMR (CDCl3): δ 7.57−7.45 (m, 2H), 7.38−7.43 (m, 3H), 7.26−
(7) (a) Beck, W.; Fehlhammer, W. P. Angew. Chem., Int. Ed. Engl.
1967, 6, 169. (b) Beck, W.; Fehlhammer, W. P.; Pollmann, P.; Schachl,
H. Chem. Ber. 1969, 102, 1976. (c) Beck, W.; Fehlhammer, W. P.;
Bock, H.; Bander, M. Chem. Ber. 1969, 102, 3637. (d) Beck, W.;
Bander, M.; Fehlhammer, W. P.; Pohlmann, P.; Schachl, H. Inorg. Nucl.
Chem. Lett. 1968, 4, 143. (e) Washburne, S. S.; Peterson, W. R., Jr. J.
Organomet. Chem. 1970, 21, 427. (f) Sisido, K.; Nabika, K.; Isida, T.;
Kozima, S. J. Organomet. Chem. 1971, 33, 337. (g) Kemmerich, T.;
Beck, W.; Spencer, C.; Mason, R. Z. Naturforsch., B: Anorg. Chem., Org.
Chem., Biochem., Biophys., Biol. 1972, 27B, 745. (h) Gaughan, A. P.;
Browman, K. S.; Dori, Z. Inorg, Chem. 1972, 11, 601. (i) Beck, W.;
Schropp, K. Chem. Ber. 1975, 108, 3317. (k) Rigby, W.; Bailey, P. M.;
McCleverty, J. A.; Maitlis, P. M. J. Chem. Soc., Dalton Trans. 1979, 371.
(8) (a) Gorth, H.; Henry, M. C. J. Organomet. Chem. 1967, 9, 117.
(b) Kozima, S.; Itano, T.; Mihara, N.; Sisido, K.; Isida, T. J. Organomet.
Chem. 1972, 44, 117.
7.24 (m, 7H), 7.16−7.14 (m, 2H), 7.01 (t, 2H, JH−H = 3.5 Hz,), 5.39
(s, 2H). 13C NMR (CDCl3): δ 144.61, 135.45, 134.03, 131.02, 130.19,
129.76, 129.22, 128.77, 128.51, 128.25, 127.92, 127.77, 127.60, 126.81,
52.14. EI-MS: m/z 312 [M + 1].
Structure Determination of Complexes 1, 2, 3a, 7, 8a, 10, 11,
12b, 12c, and 13. Single-crystal X-ray diffraction data were measured
on a Bruker SMART Apex CCD diffractometer using μ(Mo Kα)
radiation (λ = 0.71073 Å). The data collection was executed using the
SMART program; cell refinement and data reduction were performed
with the SAINT program. The structure was determined using the
SHELXTL/PC program and refined using full-matrix least-squares.43
Crystallographic refinement parameters44 of complexes 1, 2, 3a, 7, 8a,
10, 11, 12b, 12c, and 13 and selected bond distances and angles are
listed in the Supporting Information.
ASSOCIATED CONTENT
(9) Erbe, J.; Beck, W. Chem. Ber. 1983, 116, 3867.
■
(10) (a) Rosen, A.; Rosenblum, M. J. Organomet. Chem. 1974, 80,
103. (b) Ziolo, R. F.; Dori, Z. J. Am. Chem. Soc. 1968, 90, 6560.
(c) Ziolo, R. F.; Thich, J. A.; Dori, Z. Inorg. Chem. 1972, 11, 626.
(11) Sato, F.; Etoh, M.; Sato, M. J. Organomet. Chem. 1974, 70, 101.
(12) Kreutzer, P. H.; Weis, J. C.; Bock, H.; Erbe, J.; Beck, W. Chem.
Ber. 1983, 116, 2691.
S
* Supporting Information
Complete crystallographic data for 1, 2, 3a, 7, 8a, 10, 11, 12b,
12c, and 13 (CIF). This material is available free of charge via
the Internet at http://pubs.acs.org.
(13) Ellis, W. R., Jr.; Purcell, W. L. Inorg. Chem. 1982, 21, 834.
(14) Hall, J. H.; De La Vega, R. L.; Purcell, W. L. Inorg. Chim. Acta
1985, 102, 157.
AUTHOR INFORMATION
■
Notes
(15) (a) Chang, C. C.; Lee, G. H. Organometallics 2003, 22, 3107.
The authors declare no competing financial interest.
(b) Govindaswamy, P.; Mobin, S. M.; Thone, C.; Mohan Rao, K. J.
̈
Organomet. Chem. 2005, 690, 1218. (c) Liu, F.-C.; Lin, Y.-L.; Yang, P.-
S.; Lee, G. H.; Peng, S.-M. Organometallics 2010, 29, 4282.
ACKNOWLEDGMENTS
■
(16) (a) Cadierno, V.; Gamasa, M. P.; Gimeno, J. Coord. Chem. Rev.
2004, 248, 1627. (b) Rigaut, S.; Touchard, D.; Dixneuf, P. H. Coord.
Chem. Rev. 2004, 248, 1585. (c) Guerchais, V. Eur. J. Inorg. Chem.
2002, 783. (d) Bruneau, C.; Dixneuf, P. H. Acc. Chem. Res. 1999, 32,
311. (e) Puerta, M. C.; Valerga, P. Coord. Chem. Rev. 1999, 193−195,
977. (f) Cadierno, V.; Diez, J.; Gamasa, M. P.; Gimeno, J.; Lastra, E.
We gratefully acknowledge the financial support in part from
the National Science Council, Taiwan (NSC 99-2113-M-036-
001-MY3). We also thank Mr. Ting Shen Kuo (Department of
Chemistry, National Taiwan Normal University, Taiwan) for
his assistance in X-ray single-crystal structure analysis
6898
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899

Organometallics
Article
Coord. Chem. Rev. 1999, 193−195, 147. (g) Bruce, M. I. Chem. Rev.
1998, 98, 2797. (h) Touchard, D.; Dixneuf, P. H. Coord. Chem. Rev.
1998, 178−180, 409. (i) Werner, H. J. Chem. Soc., Chem. Commun.
1997, 903. (j) Bruce, M. I. Chem. Rev. 1991, 91, 197.
(34) (a) Le Bozec, H.; Ouzzine, K.; Dixneuf, P. H. Organometallics
1991, 10, 2768. (b) Beddoes, R. L.; Grime, R. W.; Hussain, Z. I.;
Whiteley, M. W. J. Organomet. Chem. 1996, 526, 371. (c) Barthel-Rosa,
L. P.; Maitra, K.; Fischer, J.; Nelson, J. H. Organometallics 1997, 16,
1714. (d) Leung, W.-H.; Chan, E. Y. Y.; Williams, I. D.; Wong, W.-T.
Organometallics 1997, 16, 3234. (e) Hansen, H. D.; Nelson, J. H.
Organometallics 2000, 19, 4740. (f) Gamasa, M. P.; Gimeno, J.;
Martín-Vaca, B. M.; Isea, R.; Vegas, A. J. Organomet. Chem. 2002, 651,
22. (g) Keller, A.; Jasionka, B.; Gzowiak, T.; Ershov, A.; Matusiak, R.
Inorg. Chim. Acta 2003, 344, 49. (h) Pavlik, S.; Mereiter, K.;
Puchberger, M.; Kirchner, K. J. Organomet. Chem. 2005, 690, 5497.
(i) Kopf, H.; Pietraszuk, C.; H€ubner, E.; Burzlaff, N. Organometallics
2006, 25, 2533.
(17) (a) Bernad, D. J.; Esteruelas, M. A.; Lopez, A. M.; Modrego, J.;
Puerta, M. C.; Valerga, P. Organometallics 1999, 18, 4995.
(b) Bianchini, C.; Casares, J. A.; Peruzzini, M.; Romerosa, A.;
Zanobini, F. J. Am. Chem. Soc. 1996, 118, 4585. (c) Barrett, G. M.;
Carpenter, N. E. Organometallics 1987, 6, 2249. (d) Ouzzine, K.; Le
Bozec, H.; Dixneuf, P. H. J. Organomet. Chem. 1986, 317, C25.
(e) Gamasa, M. P.; Gimeno, J.; Gonzaleszcueva, M.; Lastra, E. J. Chem.
Soc., Dalton Trans. 1996, 2547. (f) Nombel, P.; Lugan, N.; Mathieu, R.
J. Organomet. Chem. 1995, 503, C22. (g) Bruce, M. I.; Swincer, A. G.;
Wallis, R. C. J. Organomet. Chem. 1979, 171, C5. (h) Pavlik, S.;
Mereiter, K.; Puchberger, M.; Kirchner, K. Organometallics 2005, 24,
3561.
(18) (a) Hu, T.-C.; Hsiao, P.-I.; Wang, T.-H.; Yang, Y.-W.; Chang,
C.-Y.; Wu, Y.-H.; Sun, W.-C.; Yu, M.-S.; Lee, C.-Y.; Lo, Y.-H. Dalton
Trans. 2011, 40, 12663. (b) Lo, Y.-H.; Lin, Y.-C.; Lee, G.-H.; Wnag, Y.
Organometallics 1999, 18, 982−988. (c) Cadierno, V.; Gamasa, M. P.;
Gimeno, J.; Iglesias, L.; Garcia-Granda, S. Inorg. Chem. 1999, 38, 2874.
(d) Gamasa, M. P.; Gimeno, J.; Gonzalez-Bernardo, C.; Borge, J.;
(35) Beddoes, R. L.; Grime, R. W.; Hussain, Z. I.; Whiteley, M. W. J.
Organomet. Chem. 1996, 526, 371.
(36) Lo, Y.-H.; Chen, H.-G.; Kuo, T.-S. Dalton Trans. 2011, 40, 2711.
(37) Nagao, H.; Kikuchi, T.; Inukai, M.; Ueda, A.; Oi, T.; Suzuki, N.;
Yamasaki, M. Angew. Chem., Int. Ed. 2006, 45, 3131.
(38) Albertin, G.; Antoniutti, S.; Giorgi, M. T. Eur. J. Inorg. Chem.
2003, 2855.
(39) (a) Zhang, J.; Gunnoe, T. B.; Petersen, J. L. Inorg. Chem. 2004,
44, 2895. (b) Garnovskii, D. A.; Pombeiro, A. J. L.; Haukka, M.;
Sobota, P.; Kukushkin, V. Y. Dalton Trans. 2004, 1097.
(40) (a) Milligan, D.; Jacox, M. E. J. Chem. Phys. 1963, 39, 712.
(b) Milligan, D. E. J. Chem. Phys. 1961, 35, 1491.
(41) Zhang, L.; Chen, X.; Xue, P.; Sun, H. H. Y.; Williams, I. D.;
Sharpless, K. B.; Fokin, V. V.; Jia, G. J. Am. Chem. Soc. 2005, 127,
15998.
Garcia-Granda, S. Organometallics 1997, 16, 2483. (e) Ruba, E.;
̈
Slugovc, C.; Gemel, C.; Mereiter, K.; Schmid, R.; Kirchner, K.
Organometallics 1999, 18, 2275. (f) Bianchini, C.; Peruzzini, M.;
Romerosa, A.; Zanobini, F. Organometallics 1995, 14, 3152. (g) Barrett,
A. G. M.; Carpenter, N. E. Organometallics 1987, 6, 2249. (h) Ouzzine,
K.; Le Bozec, H.; Dixneuf, P. H. J. Organomet. Chem. 1986, 317, C25.
(i) Nombel, P.; Lugan, N.; Mathieu, R. J. Organomet. Chem. 1995, 503,
C22. (j) Le Bozec, H.; Ouzzine, K.; Dixneuf, P. H. Organometallics
1991, 10, 2768.
(42) Joo, F. Aqueous Organometallic Catalysis; Kluwer: Dordrecht,
The Netherlands, 2001.
(43) (a) The SADABS program is based on the method of Blessing;
see: Blessing, R. H. Acta Crystallogr., Sect. A 1995, 51, 33.
(b) SHELXTL: Structure Analysis Program, version 5.04; Siemens
Industrial Automation Inc.: Madison, WI, 1995.
(19) (a) Esteruelas, M. A.; Gomez, A. V.; Lopez, A. M.; Modrego, J.;
Onate, E. Organometallics 1998, 17, 5434. (b) Senn, D. R.; Wong, A.;
Patton, A. T.; Marsi, M.; Strouse, C. E.; Gladysz, J. A. J. Am. Chem. Soc.
1988, 110, 6096.
(20) Ting, P. C.; Lin, Y. C.; Lee, G. H.; Cheng, M. C.; Wang, Y. J.
Am. Chem. Soc. 1996, 118, 6433.
2
(44) GOF = [∑[w(Fo − Fc2)2]/(n − p)]1/2, where n and p denote
the number of data and parameters. R1= (∑||Fo| − |Fc||)/∑|Fo|, wR2 =
2
2
2
[∑[w(Fo − F 2) ]/a[w(F )2]]1/2 where w = 1/[σ2(Fo ) + (aP)2 +
̊
c
2
o
bP] and P = [(max; 0, Fo ) + 2Fc2]/3.
2
(21) Nathaniel, W.; Alock, N. W.; Burns, I. D.; Claire, K. S.; Hill, A.
F. Inorg. Chem. 1992, 31, 2906.
(22) Singleton, E.; Ooethuizen, H. E. Adv. Organomet. Chem. 1983,
22, 209.
(23) Busetto, L.; Palazzi, A.; Ros, R. Inorg. Chim. Acta 1975, 13, 233.
(24) Chen, C.-K.; Tong, H.-C.; Chen Hsu, C.-Y.; Lee, C.-Y.; Fong,
Y.-S.; Chung, Y.-S.; Lo, Y.-H.; Lin, Y.-C.; Wang, Y. Organomtallics
2009, 28, 3358.
(25) Paul, P.; Nag, K. Inorg. Chem. 1987, 26, 2969.
(26) (a) Nelson, J. H.; Schmitt, D. L.; Henty, R. A.; Moore, D. W.;
Jonassen, H. B. Inorg. Chem. 1970, 9, 2678. (b) Redfield, D. A.;
Nelson, J. H.; Henry, R. A.; Moore, D. W.; Jonassen, H. B. J. Am.
Chem. Soc. 1974, 96, 6298.
(27) Kieft, R. L.; Peterson, W. M.; Blundell, G. L.; Horton, S.; Henry,
R. A.; Jonasson, H. B. Inorg. Chem. 1976, 15, 1721.
(28) Kemmerich, T.; Nelson, J. H.; Takach, N. E.; Boeheme, H.;
Jablonski, B.; Beck, W. Inorg. Chem. 1982, 21, 1226.
(29) Singh, K. S.; Kreisel, K. A.; Yap, G. P.; Kollipara, M. R. J.
Organomet. Chem. 2006, 691, 3509.
(30) (a) Parashad, R.; Yadav, S. K. S.; Agarwala, U. J. Inorg. Nucl.
Chem. 1981, 43, 2359. (b) Rowley, M.; Steed, J. W.; Tocher, D. A.
Polyhedron 1995, 14, 1415. (c) Preetz, W.; Fricke, H. H. Z. Anorg. Allg.
Chem. 1982, 486, 49. (d) Poddar, R. K.; Parashad, R.; Agarwala, U. J.
Inorg. Nucl. Chem. 1980, 42, 837. (e) Kohle, O.; Ruile, S.; Gratzel, M.
̈
Inorg. Chem. 1996, 35, 4779.
(31) Homanen, P.; Haukka, M.; Pakkanen, T. A.; Pursiainen, J.;
Laitinen, R. H. Organometallics 1996, 15, 4081.
(32) (a) Tokunaga, M.; Suzuki, T.; Koga, N.; Fukushima, T.;
Horiuchi, A.; Wakatsuki, Y. J. Am. Chem. Soc. 2001, 123, 11917.
(b) Grotjahn, D. B.; Lev, D. A. J. Am. Chem. Soc. 2004, 126, 12232.
(33) Bianchini, C.; Casares, J. A.; Peruzzini, M.; Romerosa, A.;
Zanobini, F. J. Am. Chem. Soc. 1996, 118, 4585.
6899
dx.doi.org/10.1021/om300687a | Organometallics 2012, 31, 6887−6899