Synthesis and reactivity of bis(3,5-dimethylpyrazol-1-yl)methanes functionalized by 2-halophenyl groups on the methine carbon

Article abstract of DOI:10.1016/j.jorganchem.2012.08.004

Three new bis(3,5-dimethylpyrazol-1-yl)methanes [(2-XC₆H ₄)CH(3,5-Me₂Pz)₂, X = F, Cl and Br] functionalized by 2-halophenyl groups on the methine carbon atom have been synthesized. Upon heating (2-XC₆H₄)CH(3,5-Me ₂Pz)₂ with Mo(CO)₆ or W(CO)₅THF in THF at reflux, complexes (2-XC₆H₄)CH(3,5-Me ₂Pz)₂M(CO)₄ (X = F or Cl, M = Mo or W) were obtained. While the similar reaction of (2-BrC₆H₄)CH(3,5- Me₂Pz)₂ led to the oxidative addition of the C-Br bond to the Mo or W center to give complexes (C₆H₄)CH(3,5-Me ₂Pz)₂M(CO)₃Br (M = Mo or W). In addition, 2-ImC₆H₄CH(3,5-Me₂Pz)₂ (Im = imidazol-1-yl) has been obtained by the reaction of (2-BrC₆H ₄)CH(3,5-Me₂Pz)₂ with imidazole, which subsequently reacted with PhCH₂Cl to form 1-{2-[bis(3,5- dimethylpyrazol-1-yl)methyl]phenyl}-3-benzylimidazium chloride. Treatment of this imidazole salt with Ag₂O and succeedingly with W(CO) ₅THF or Ru₃(CO)₁₂ yielded N-heterocylic carbene complexes LW(CO)₅ and LRu₃(CO)₈(μ-H)(μ- Cl) (L = 1-{2-[bis(3,5-dimethylpyrazol-1-yl)methyl]phenyl}-3-benzylimidazol-2- ylidene), respectively. In the former, L acts as a monodentate ligand by the carbene carbon to the tungsten atom, and two pyrazolyl nitrogen atoms do not take part in the coordination to the metal center. While in the latter, L serves as a bridging bidentate ligand by one pyrazolyl nitrogen and the carbene carbon atoms to a Ru-Ru bond, and a hydride along with a chloride ligand bridges this metal-metal bond.

Full text of DOI:10.1016/j.jorganchem.2012.08.004

Journal of Organometallic Chemistry 718 (2012) 89e95
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis and reactivity of bis(3,5-dimethylpyrazol-1-yl)methanes functionalized
by 2-halophenyl groups on the methine carbon
*
Da-Wei Zhao, Yun-Fu Xie, Hai-Bin Song, Liang-Fu Tang
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
a r t i c l e i n f o
a b s t r a c t
Article history:
Three new bis(3,5-dimethylpyrazol-1-yl)methanes [(2-XC6H4)CH(3,5-Me2Pz)2, X ¼ F, Cl and Br] func-
tionalized by 2-halophenyl groups on the methine carbon atom have been synthesized. Upon heating (2-
XC6H4)CH(3,5-Me2Pz)2 with Mo(CO)6 or W(CO)5THF in THF at reflux, complexes (2-XC6H4)CH(3,5-
Me2Pz)2M(CO)4 (X ¼ F or Cl, M ¼ Mo or W) were obtained. While the similar reaction of (2-BrC6H4)
CH(3,5-Me2Pz)2 led to the oxidative addition of the CeBr bond to the Mo or W center to give complexes
(C6H4)CH(3,5-Me2Pz)2M(CO)3Br (M ¼ Mo or W). In addition, 2-ImC6H4CH(3,5-Me2Pz)2 (Im ¼ imidazol-1-
yl) has been obtained by the reaction of (2-BrC6H4)CH(3,5-Me2Pz)2 with imidazole, which subsequently
reacted with PhCH2Cl to form 1-{2-[bis(3,5-dimethylpyrazol-1-yl)methyl]phenyl}-3-benzylimidazium
chloride. Treatment of this imidazole salt with Ag2O and succeedingly with W(CO)5THF or Ru3(CO)12
Received 8 June 2012
Received in revised form
29 July 2012
Accepted 2 August 2012
Keywords:
Bis(pyrazol-1-yl)methane
N-heterocyclic carbene
Oxidative addition
Group 6 metal carbonyl complex
Ru3(CO)12
yielded N-heterocylic carbene complexes LW(CO)5 and LRu3(CO)8(
m
-H)(
m
-Cl) (L
¼
1-{2-[bis(3,5-
dimethylpyrazol-1-yl)methyl]phenyl}-3-benzylimidazol-2-ylidene), respectively. In the former, L acts
as a monodentate ligand by the carbene carbon to the tungsten atom, and two pyrazolyl nitrogen atoms
do not take part in the coordination to the metal center. While in the latter, L serves as a bridging
bidentate ligand by one pyrazolyl nitrogen and the carbene carbon atoms to a RueRu bond, and a hydride
along with a chloride ligand bridges this metalemetal bond.
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
containing nucleophiles have also been one of the most useful
and practical methods for the formation of the carbon-heteroatom
Bis(pyrazol-1-yl)methanes modified by organic functional
groups on the bridging carbon atom have drawn extensive atten-
tion in recent years, owing to their versatile coordination chemistry
toward main group and transition metals [1e3]. Our existing
investigations on bis(pyrazol-1-yl)methanes indicate that modifi-
cation of these ligands with organic groups on the methine carbon
can provide unusual reactivity [4e7]. For instance, the reaction of
bis(pyrazol-1-yl)methanes functionalized by 2-hydroxyphenyl or
2-methoxyphenyl on the bridgehead carbon atom with W(CO)5THF
resulted in the cleavage of a Csp3eN bond to form novel pyrazole
derivatives [4], which inspires us to expand this investigation to
gain deeper understanding, such as the effect of other substituents
of the phenyl group on this reaction. On the other hand, although
the oxidative addition of the CeX bond to the tungsten(0) atom
appeared in 1987 [8], the cases of the oxidative addition of the CeX
bond to group 6 metal(0) are still rare in literature [8e16]. In
addition, the coupling reactions of aryl halides with heteroatom-
bonds [17]. Thus, it should be interesting to synthesize and exploit
the relative reactivity of bis(3,5-dimethylpyrazol-1-yl)methanes
functionalized by 2-halophenyl groups.
2. Results and discussion
2.1. Synthesis and reaction of 2-halophenylbis(3,5-
dimethylpyrazol-1-yl)methanes
2-Halophenylbis(3,5-dimethylpyrazol-1-yl)methanes
were
easily obtained by the catalyzed Peterson rearrangement [18e20]
starting from bis(3,5-dimethylpyrazol-1-yl)methanone and 2-
halobenzenealdehydes (Scheme 1). These ligands have demon-
strated different reactivities, upon treatment with group 6 metal
carbonyl complexes. For example, reactions of ligands 1 and 2 with
Mo(CO)6 or W(CO)5THF in refluxing THF yielded the decarbon-
ylation complexes 4e7, while the similar reaction of ligand 3
resulted in the oxidative addition of the CeBr bond to the molyb-
denum(0) or tungsten(0) atom to give novel heterometallacyclic
complexes 9 and 10. These results are well correlated with the CeX
bond strengths [11]. In addition, irradiation of ligand 3 with W(CO)6
* Corresponding author. Fax: þ86 22 23502458.
E-mail address: lftang@nankai.edu.cn (L.-F. Tang).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.08.004

90
D.-W. Zhao et al. / Journal of Organometallic Chemistry 718 (2012) 89e95
Fig. 1. The molecular structure of 7. The thermal ellipsoids are drawn at the 30%
ꢁ
ꢀ
probability level. Selected bond distances (A) and angles ( ): W(1)eN(2) 2.268(3),
ꢀ
W(1)eN(4) 2.288(4), C(7)eN(1) 1.444(5), C(7)eN(3) 1.450(6) A; W(1)eC(18)eO(1)
179.9(4), W(1)eC(19)eO(2) 171.9(5), W(1)eC(20)eO(3) 176.5(4), W(1)eC(21)eO(4)
167.8(4), C(19)eW(1)eC(21) 164.9(2), N(2)eW(1)eN(4) 79.4(1), N(1)eC(7)eN(3)
109.3(3), N(3)eC(7)eC(6) 112.6(4)ꢁ.
Scheme 1. Synthesis and reaction of 2-halophenylbis(pyrazol-1-yl)methanes.
at room temperature afforded the decarbonylation complex 8, and
subsequently heating this complex in refluxing THF also led to the
oxidative addition of the CeBr bond to form complex 10.
Fig. 2 clearly displays that the bromine atom has been transferred
to the tungsten center, and new tungstenecarbon bond and
tungstenebromine bond have been formed by the oxidative addi-
tion reaction of the CeBr bond to the tungsten(0) atom. The ligand
Although complexes 4e10 were slightly air-sensitive, their
solutions could be manipulated in the air without notable
decomposition. These complexes have been characterized by
elemental analyses, IR and NMR spectroscopy. The IR spectra of
complexes 4e8 are markedly different from those of complexes 9
and 10. Four strong nCO bands in the range of 1814e2014 cmꢀ1 are
observed in complexes 4e8, indicating a typical cis-tetracarbonyl
arrangement. While three such absorption peaks in the range of
1896e2014 cmꢀ1 are found in complexes 9 and 10, consistent with
the structure of the seven-coordinated tricarbonyl species [8,13]. It
is noteworthy that a proton signal of the phenyl group markedly
shifts upfield by ca. 1 ppm in complexes 4e8, compared with those
of free ligands 1e3. The most reasonable interpretation of these
remarkable changes in NMR would be the effect of the pyrazole ring
when the proton is located in the shielding region of the magnes-
tically anisotropic ring. The explanation was then confirmed by the
X-ray crystal structure of complex 7 (Fig. 1) which shows that the
proton on the C(5) atom is situated over the N(4)eN(3)eC(13)e
C(14)eC(15) pyrazolyl plane. The free rotation of the phenyl ring
around the CeC bond may be prevented by the steric repulsion
among substituents. Similar results are observed in other aryl-
bis(pyrazol-1-yl)methane derivatives [4,21].
acts as a tridentate and monoanionic k
3-[N,C,N] chelating ligand
through one phenyl carbon and two pyrazolyl nitrogen atoms. The
dihedral angles of the phenyl ring with two pyrazolyl rings are 62.3ꢁ
(the N(2)eC(7) plane) and 70.9ꢁ (the N(4)eC(12) plane), respec-
ꢀ
tively. The W(1)eC(16) distance is 2.235(4) A, comparable to those in
ꢀ
BrC6H4CH]NCH2CH2N]CHC6H4W(CO)3Br (A) (2.20(2) A) [8] and
ꢀ
C6H4CH]NC6H4NH2W(CO)3F (2.232(6) A) [9]. The W(1)eBr(1) bond
The structures of complexes
7
and 10 have been
further confirmed by X-ray structural analyses, and presented in
Figs. 1 and 2, respectively. Fig. 1 shows that ligand 2 acts as an N,N-
bidentate chelating ligand in complex 7, and the tungsten atom
adopts a distorted octahedral coordination geometry. The phenyl
ring locates on the axial position of the boat conformation of the
metallacyle, and is perpendicular to the N(4)eN(3)eC(13)eC(14)e
C(15) pyrazolyl plane with a dihedral angle of 90.0ꢁ. The average
ꢀ
WeN bond distance is 2.278 A, similar to that in (2-MeOC6H4)
ꢀ
CH(3,5-Me2Pz)2W(CO)4 (2.271 A) [4]. The angles of W(1)eC(21)e
Fig. 2. The molecular structure of 10. The thermal ellipsoids are drawn at the 30%
ꢁ
O(4) (167.8(4)ꢁ) and W(1)eC(19)eO(2) (171.9(5)ꢁ) remarkably
deviate from linearity, reflecting the presence of large steric
repulsion between these two carbonyls with ligands, especially
with the phenyl and the 3-position methyl groups of pyrazolyl
rings.
ꢀ
probability level. Selected bond distances (A) and angles ( ): W(1)eN(1) 2.226(6),
W(1)eN(3) 2.227(6), W(1)eBr(1) 2.699(2), W(1)eC(16) 2.235(4), C(14)eN(2) 1.451(7),
ꢀ
C(14)eN(4) 1.461(7) A; W(1)eC(1)eO(1) 175.9(5), W(1)eC(2)eO(2) 177.2(5), W(1)e
C(3)eO(3) 177.8(5), N(1)eW(1)eN(3) 82.9(2), N(2)eC(14)eN(4) 110.1(4), N(2)eC(14)e
C(15) 112.2(3), C(16)eW(1)eBr(1) 153.5(1), N(1)eW(1)eC(3) 164.9(2), N(1)eW(1)e
Br(1) 80.2(1)ꢁ.

D.-W. Zhao et al. / Journal of Organometallic Chemistry 718 (2012) 89e95
91
ꢀ
distance is 2.699(2) A, slightly longer than the corresponding bond in
atom, and two pyrazolyl nitrogen atoms do not take part in the
coordination to the metal center (Fig. 3), consistent with the
spectroscopic analyses of IR and NMR. The W-CNHC bond distance is
complex A (2.651(2) A) [8] and (h5-C9H7)W(CO)3Br (2.6453(3) A)
[16]. The average WeN bond distance is 2.2265 A, slightly shorter
than that in complex 7, possibly since the relative strong Lewis
acidity of the tungsten(II) atom in complex 10 strengthens the WeN
bond.
ꢀ
ꢀ
ꢀ
ꢀ
2.268(3) A, falling within the range of values observed in NHC-
ꢀ
supported W(CO)5 complexes (2.242e2.299 A) [30e34]. The
angles of N(1)eC(6)eC(7) (113.8(2)ꢁ) and N(5)eC(22)eC(21)
(114.6(2)ꢁ) deviate from the tetrahedral geometry of the sp3-
hybridized carbon atoms. Five carbonyls, especially two cis-
carbonyls (C(1)O(1) and C(4)O(4)), are distorted. These geometric
features suggest a large steric repulsion in this complex, as
mentioned by its NMR spectra. To decrease the steric repulsion, the
phenyl ring of benzyl group and pyrazolyl rings are driven away
from the metal center. At the same time, the steric repulsion
hinders the polydentate NHC’s ability to act as a [N,C] bidentate or
[N,N,C] tridentate ligand in mononuclear tungsten derivatives.
Complex 13 decomposed upon heated at high temperature.
Recently, the coordination chemistry of polydentate NHCs toward
transition metal carbonyl clusters has received increasing attention
[35]. Remarkable CeH bondactivationprocesses were often observed
in the reactions of polydentate NHCs with transition metal carbonyl
clusters, especially triruthenium and triosmium clusters [36,37].
Herein, we found that the direct thermolysis of the imidazole salt 12
with Ru3(CO)12 in THF at reflux resulted in the decomposition of the
ligand. While the reaction of 12 with Ag2O and succeeding treatment
with Ru3(CO)12 yielded NHC derivative 14 (Scheme 2). Although no
CeH bond activationwas detected in this reaction, the eliminated HCl
molecule did not depart from the reaction system, but coordinated to
a RueRu bond to forma hydrideand a chloridebridges. Inthe 1H NMR
spectrum of complex 14, the signal of the hydride ligand appeared at
ꢀ11.3 ppm. The NMR resonance of the carbene carbon was observed
at 179.0 ppm. Although it seems that 14 can be regarded as a product
of the direct reaction of 12 with Ru3(CO)12, the corresponding reac-
tion of these two compounds does not occur at room temperature
and leads to the decomposition of the ligand at reflux in THF. The
possible pathway of the formation of 14 is not entirely clear at
present, which should involve NHC transferring reaction of AgeNHC
complex in the first step.
2.2. Synthesis of NHC complexes bearing bis(3,5-dimethylpyrazol-
1-yl)methyl group
Since the first stable free N-heterocyclic carbene (NHC) was
isolated and characterized [22], the NHC chemistry has been
flourishing over two decades [23e25]. In recent years, lots of
nitrogen-, oxygen- and sulfur-functionalized NHC ligands have
been obtained [26e28]. Owing to the introduction of the additional
donor atoms on the side-arm of NHCs, these functionalized NHCs
often exhibit novel reactivity patterns in the reactions with tran-
sition metals, and provide relatively stable and efficient catalysts or
catalyst precursors. On the other hand, as one of the most popular
nitrogen-containing donor ligands, bis(pyrazol-1-yl)methanes
have been extensively exploited to form various transition metal
complexes [1e3]. Thus we reason that NHCs bearing bis(pyrazol-1-
yl)methyl fragment can act as very useful ligands for transition
metals.
Ligand 11 was obtained by the coupling reaction of ligand 3 with
imidazole (Scheme 2), which subsequently reacted with PhCH2Cl to
form the imidazole salt 12. Treatment of 12 with Ag2O and suc-
ceedingly with W(CO)5THF yielded N-heterocylic carbene complex
13, which was characterized by elemental analyses, IR and NMR
spectroscopy. The IR spectrum of 13 shows a nCO absorption at
2060 cmꢀ1, corresponding to the A1eq mode for the pseudo C4v
metal center in a metal pentacarbonyl moiety [29], consistent with
the existing of W(CO)5 fragment in this complex. Its 13C NMR
spectrum also supports the proposed structure, which unambigu-
ously shows two signals of the carbonyl carbon atoms with ca. a 1:4
intensity ratio. In addition, 1H NMR spectrum of 13 indicates the
methylene protons of the benzyl group are not equivalent, and an
AB system is observed at room temperature. Furthermore, two sets
of 1H and 13C signals of the pyrazolyl moiety are observed in these
spectra. These results suggest that large steric repulsion should
exist in 13, which prevents the free rotation of the pyrazolyl and
benzyl groups.
The molecular structure of 14 was determined by X-ray
diffraction analysis, which consisted of two crystallographically
The structure determination of complex 13 reveals that the NHC
acts as a monodentate ligand by the carbene carbon to the tungsten
Fig. 3. The molecular structure of 13. The thermal ellipsoidꢁs are drawn at the 30%
ꢀ
probability level. Selected bond distances (A) and angles ( ): W(1)eC(1) 2.047(3),
W(1)eC(3) 1.999(3), W(1)eC(13) 2.268(3), C(22)eN(3) 1.458(3), C(22)eN(5) 1.449(3)
ꢀ
A; W(1)eC(1)eO(1) 171.4(2), W(1)eC(2)eO(2) 176.7(3), W(1)eC(3)eO(3) 177.6(3),
W(1)eC(4)eO(4) 173.5(3), W(1)eC(5)eO(5) 176.3(3), N(1)eC(6)eC(7) 113.8(2), N(1)e
C(13)eN(2) 102.8(2), N(3)eC(22)eN(5) 110.6(2), N(3)eC(22)eC(21) 113.5(2), N(5)e
C(22)eC(21) 114.6(2), N(1)eC(13)eW(1) 129.9(2), C(1)eW(1)eC(4) 168.0(1), C(3)e
W(1)eC(13) 178.0(1), C(2)eW(1)eC(13) 90.7(1)ꢁ.
Scheme 2. Synthesis of NHC complexes bearing bis(pyrazol-1-yl)methanes.

92
D.-W. Zhao et al. / Journal of Organometallic Chemistry 718 (2012) 89e95
independent molecules with similar structural parameters. One of
them is shown in Fig. 4. The NHC acts as a bridging bidentate ligand
by one pyrazolyl nitrogen and the carbene carbon to a RueRu bond,
and a hydride along with a chloride ligand bridges this metale
metal bond. The hydride-bridged RueRu bond distance (Ru(1)e
analyzer. HR mass spectra were carried out on a Varian QFT-ESI
spectrometer. Melting points were measured with an X-4 digital
micro melting-point apparatus and were uncorrected. Bis(3,5-
dimethylpyrazol-1-yl)methanone [21] was prepared according to
the literature method.
ꢀ
Ru(3) 2.8504(5) A) is slightly longer than the corresponding
ꢀ
unbridged RueRu bond distances (Ru(1)eRu(2) 2.8038(7) A and
3.1. Synthesis of (2-FC6H4)CH(3,5-Me2Pz)2 (1)
ꢀ
Ru(2)eRu(3) 2.8161(5) A). These three RueRu bond distances fall in
the range of RueRu distances found in other triruthenium NHC
complexes [36,37]. The RueCNHC bond distance (Ru(3)eC(28)) is
The mixture of bis(3,5-dimethylpyrazol-1-yl)methanone
(3.06 g, 14 mmol), CoCl2$6H2O (22 mg, 0.092 mmol) and 2-
FC6H4CHO (1.74 g, 14 mmol) was stirred and heated at 80 ꢁC for
1 h. Then the reaction temperature was elevated to 115 ꢁC, and the
reaction mixture was continuously stirred for 1 h. After cooling to
room temperature, CH2Cl2 (80 ml) was added to the reaction
mixture to dissolve the solid. The CH2Cl2 solution was washed with
water three times (3 ꢂ 40 ml), and dried over anhydrous MgSO4.
After removing of the solvent, the residue was recrystallized from
benzene/hexane to give white crystals of 1. Yield: 2.52 g (60%), mp
ꢀ
2.100(2) A, comparable to the RueCNHC bond distances found in
ꢀ
[Ru3(
m
-H)(m3-pyCH2ImMe)(CO)9] (2.059(3 A) and [Ru3(
m-H)2(m3
-
ꢀ
HCpyCH2ImMe)(CO)8] (2.092(7) A) [36].
In summary, three new bis(3,5-dimethylpyrazol-1-yl)methanes
functionalized by 2-halophenyl groups on the methine carbon
atom can be easily obtained. Oxidative addition reaction only takes
place on the CeBr bond to the Mo or W center when these three
ligands react with Mo(CO)6 and W(CO)5THF. The NHC complexes
bearing bis(pyrazol-1-yl)methyl group have been successfully
synthesized, in which the polydentate NHC ligands show variable
coordination modes, depending on different metal atoms.
118e120 ꢁC. 1H NMR:
d
2.14, 2.22 (s, s, 6H, 6H, CH3), 5.86 (s, 2H, H4 of
pyrazole), 6.88 (t, J ¼ 7.4 Hz, 1H), 7.04e7.15 (m, 2H), 7.32e7.39 (m,
1H) (C6H4), 7.71 (s, 1H, CH) ppm. 13C NMR:
d 11.2, 13.7 (CH3), 69.4
(CH), 106.9 (C4 of pyrazole), 115.3 (d, JFC ¼ 20.9 Hz), 124.1, 124.2,
128.9, 130.5 (d, JFC ¼ 8.1 Hz), 158.4 (C6H4), 140.3, 148.3 (C3 and C5 of
pyrazole) ppm. Anal. Calc. for C17H19FN4: C, 68.44; H, 6.42; N, 18.78.
Found: C, 68.20; H, 6.76; N, 18.41%.
3. Experimental
Solvents were dried and distilled prior to use according to
standard procedures. All reactions were carried out under an
atmosphere of argon. NMR (1H and 13C) were recorded on a Bruker
400 spectrometer using CDCl3 as solvent unless otherwise noted,
and the chemical shifts were reported in ppm with respect to the
reference (internal SiMe4 for 1H and 13C NMR spectra). IR spectra
were recorded as KBr pellets on a Nicolet 380 spectrometer.
Element analyses were carried out on an Elementar Vairo EL
3.2. Synthesis of (2-ClC6H4)CH(3,5-Me2Pz)2 (2)
This compound was obtained similarly using 2-ClC6H4CHO
instead of 2-FC6H4CHO as described above for 1 as white crystals,
but the reaction temperature was 80 ꢁC, and the reaction time was
1 h. Yield: 70%, mp 144e146 ꢁC. 1H NMR:
d 2.09, 2.18 (s, s, 6H, 6H,
CH3), 5.86 (s, 2H, H4 of pyrazole), 6.83 (d, J ¼ 7.9 Hz, 1H), 7.19e
7.29 (m, 2H), 7.34e7.37 (m, 1H) (C6H4), 7.62 (s, 1H, CH) ppm. 13C
NMR: d
11.1, 13.8 (CH3), 71.8 (CH), 106.8 (C4 of pyrazole), 127.1, 129.1,
129.6, 129.9, 133.2, 134.5 (C6H4), 140.3, 148.4 (C3 and C5 of pyrazole)
ppm. Anal. Calc. for C17H19ClN4: C, 64.86; H, 6.08; N,17.80. Found: C,
64.41; H, 6.54; N, 17.82%.
3.3. Synthesis of (2-BrC6H4)CH(3,5-Me2Pz)2 (3)
This compound was obtained similarly using 2-BrC6H4CHO
instead of 2-FC6H4CHO as described above for 1 as white crystals.
Yield: 61%, mp 153e154 ꢁC. 1H NMR:
d 2.11, 2.21 (s, s, 6H, 6H, CH3),
5.89 (s, 2H, H4 of pyrazole), 6.83 (d, J ¼ 7.7 Hz, 1H), 7.23e7.29 (m,
2H) (C6H4), 7.57e7.59 (m, 2H, C6H4 and CH) ppm. 13C NMR:
d 11.1,
13.8 (CH3), 73.7 (CH), 106.8 (C4 of pyrazole), 123.1, 127.7, 129.4, 130.1,
132.9, 136.1 (C6H4), 140.4, 148.4 (C3 and C5 of pyrazole) ppm. Anal.
Calc. for C17H19BrN4: C, 56.83; H, 5.33; N, 15.59. Found: C, 56.41; H,
5.78; N, 15.09%.
3.4. Synthesis of (2-FC6H4)CH(3,5-Me2Pz)2Mo(CO)4 (4)
The solution of 1 (0.30 g, 1.0 mmol) and Mo(CO)6 (0.26 g,
1.0 mmol) in THF (50 ml) was stirred and heated at reflux for 4 h.
The solvent was removed under reduced pressure, and the residue
was purified by column chromatography on silica using CH2Cl2/
hexane (2/1 v/v) as eluent. The eluate was concentrated to dryness
and the residual solid was recrystallized from CH2Cl2/hexane to
Fig. 4. The molecular structure of 14. The thermal ellipsoids are drawn at the 30%
ꢁ
ꢀ
probability level. Selected bond distances (A) and angles ( ): Ru(1)eRu(2) 2.8038(7),
Ru(1)eRu(3) 2.8504(5), Ru(2)eRu(3) 2.8161(5), Ru(1)eCl(1) 2.4669(8), Ru(1)eN(1)
2.301(2), Ru(1)eH(1) 1.89(3), Ru(3)eCl(1) 2.4900(8), Ru(3)eH(1) 1.90(3), Ru(3)eC(28)
give yellowegreen solids of 4. Yield: 0.32 g (63%). 1H NMR:
d 2.48,
2.59 (s, s, 6H, 6H, CH3), 6.11 (s, 2H, H4 of pyrazole), 6.15e6.18 (m,
1H), 7.04e7.18 (m, 2H), 7.37e7.43 (m, 1H) (C6H4), 7.48 (s, 1H, CH)
ꢀ
2.100(2), C(19)eN(2) 1.471(3), C(19)eN(3) 1.454(3) A; Ru(1)eRu(2)eRu(3) 60.954(9),
Ru(1)eCl(1)eRu(3) 70.20(2), Ru(1)eH(1)eRu(3) 97.7(1), Ru(2)eRu(1)eRu(3) 59.74(1),
N(1)eRu(1)eRu(2) 176.58(5), N(1)eRu(1)eRu(3) 117.19(5), C(28)eRu(3)eRu(2)
172.67(7), N(2)eN(1)eRu(1) 129.6(2), N(5)eC(28)eRu(3) 127.1(2), N(2)eC(19)eN(3)
111.3(2), N(6)eC(29)eC(20) 113.5(2)ꢁ.
ppm. 13C NMR:
d
11.7, 16.5 (CH3), 65.2 (CH), 108.0 (C4 of pyrazole),
117.3 (d, JFC ¼ 21.7 Hz), 121.3 (d, JFC ¼ 10.1 Hz), 125.5, 128.1, 132.1 (d,
JFC ¼ 8.5 Hz), 142.1 (C6H4), 155.5, 158.4 (C3 and C5 of pyrazole), 202.6

D.-W. Zhao et al. / Journal of Organometallic Chemistry 718 (2012) 89e95
93
(1C), 205.8 (1C), 220.9 (2C) (CO) ppm. IR: nCO ¼ 2014.6 (s), 1892.9
(vs), 1868.2 (vs), 1814.0 (vs) cmꢀ1. Anal. Calc. for C21H19FMo-
N4O4.0.25CH2Cl2: C, 48.38; H, 3.73; N, 10.62. Found: C, 48.80; H,
3.48; N, 11.00%.
1H, J ¼ 7.0 Hz), 7.11e7.23 (m, 2H), 7.49e7.52 (m, 1H) (C6H4), 7.78 (s,
1H, CH) ppm. 13C NMR (acetone-d6):
d 12.3, 17.4 (CH3), 69.7 (CH),
109.2 (C4 of pyrazole), 120.6, 129.6, 129.8, 132.1, 134.0, 136.9 (C6H4),
146.0, 156.8 (C3 and C5 of pyrazole), 201.3 (1C), 204.9 (1C), 212.6
(2C) (CO) ppm. IR: nCO ¼ 2002.1 (s), 1880.2 (vs), 1847.5 (vs), 1818.3
(vs) cmꢀ1. Anal. Calc. for C21H19BrN4O4W: C, 38.50; H, 2.92; N, 8.55.
Found: C, 38.57; H, 2.62; N, 8.67%.
3.5. Synthesis of (2-FC6H4)CH(3,5-Me2Pz)2W(CO)4 (5)
Compound 1 (0.27 g, 0.91 mmol) was added to a solution of
W(CO)5THF in THF, prepared in situ by the irradiation of a solution
of W(CO)6 (0.32, 0.91 mmol) in THF (40 ml) with a 300 W high-
pressure mercury lamp for 8 h, and the reaction mixture was stir-
red and heated at reflux for 10 h. Then the solvent was removed
under reduced pressure, and the residual solid was purified by
column chromatography on silica using CH2Cl2/hexane (2/1 v/v) as
eluent. The eluate was concentrated to dryness and the residual
solid was recrystallized from CH2Cl2/hexane to give yellowegreen
3.9. Synthesis of (2-C6H4)CH(3,5-Me2Pz)2Mo(CO)3Br (9)
This complex was obtained similarly using compound 3 instead
of compound 1 as described above for 4. Yield: 44%. 1H NMR
(DMSO-d6):
d
2.33, 2.65 (s, s, 6H, 6H, CH3), 6.22 (s, 2H, H4 of pyr-
azole), 7.07e7.21 (m, 2H), 7.33 (dd, J ¼ 7.1 Hz, J ¼ 1.3 Hz, 1H), 7.97
(dd, J ¼ 7.1 Hz, J ¼ 1.5 Hz, 1H) (C6H4), 7.58 (s, 1H, CH) ppm. 13C NMR
(DMSO-d6): d
10.7,15.4 (CH3), 70.4 (CH),107.7 (C4 of pyrazole),124.7,
solids of 5. Yield: 0.25 g (47%). 1H NMR (acetone-d6):
d
2.40, 2.51
128.7, 128.9, 136.7, 142.1, 161.4 (C6H4), 142.2, 152.5 (C3 and C5 of
pyrazole), 236.9 (CO) ppm. IR: nCO ¼ 2013.7 (vs), 1942.3 (vs), 1903.7
(vs) cmꢀ1. Anal. Calc. for C20H19BrMoN4O3: C, 44.55; H, 3.55; N,
10.39. Found: C, 44.65; H, 3.76; N, 10.28%.
(s, s, 6H, 6H, CH3), 6.35 (s, 2H, H4 of pyrazole), 6.21 (t, J ¼ 8.1 Hz),
7.11e7.19 (m, 2H), 7.40e7.45 (m, 1H) (C6H4), 8.07 (s, 1H, CH) ppm.
13C NMR: 11.8, 17.3 (CH3), 65.8 (CH), 108.2 (C4 of pyrazole), 117.5 (d,
d
JFC ¼ 21.8 Hz), 120.8 (d, JFC ¼ 10.9 Hz), 125.7, 127.9, 132.3 (d,
JFC ¼ 8.6 Hz), 158.4 (C6H4), 142.2, 156.1 (C3 and C5 of pyrazole), 200.5
(1C), 203.5 (1C), 212.0 (2C) (CO) ppm. IR: nCO ¼ 2003.0 (s), 1891.0
3.10. Synthesis of (2-C6H4)CH(3,5-Me2Pz)2W(CO)3Br (10)
(vs), 1850.7 (vs), 1821.0 (vs) cmꢀ1
.
Anal. Calc. for
Compound 3 (0.32 g, 0.91 mmol) was added to a solution of
W(CO)5THF in THF, prepared in situ by the irradiation of a solution
of W(CO)6 (0.32, 0.91 mmol) in THF (40 ml) with a 300 W high-
pressure mercury lamp for 8 h, and the reaction mixture was stir-
red and heated at reflux for 24 h. Then the solvent was removed
under reduced pressure, and the residual solid was purified by
column chromatography on silica using ethyl acetate/hexane (1/1
v/v) as eluent. The first yellowegreen band was characterized as
complex 8. Yield: 35 mg (5.9%). The second yellow band was
confirmed as complex 10. Yield: 0.15 g (27%). 1H NMR (DMSO-d6):
C21H19FN4O4W.0.25CH2Cl2: C, 41.47; H, 3.19; N, 9.10. Found: C,
41.24; H, 3.62; N, 9.60%.
3.6. Synthesis of (2-ClC6H4)CH(3,5-Me2Pz)2Mo(CO)4 (6)
This complex was obtained similarly using compound 2 instead
of compound 1 as described above for 4. Yield: 56%. 1H NMR:
d 2.47,
2.53 (s, s, 6H, 6H, CH3), 6.09 (s, 2H, H4 of pyrazole), 6.04e6.07 (m,
1H), 7.20e7.21 (m, 1H) (C6H4), 7.30e7.33 (m, 2H, C6H4 and CH),
7.37e7.41 (m, 1H, C6H4) ppm. 13C NMR:
d
12.1, 16.5 (CH3), 67.0 (CH),
d
2.35, 2.67 (s, s, 6H, 6H, CH3), 6.30 (s, 2H, H4 of pyrazole), 7.02 (t,
108.2 (C4 of pyrazole), 128.2, 128.9, 131.2, 131.3, 131.8, 132.4 (C6H4),
142.5, 155.8 (C3 and C5 of pyrazole), 202.5 (1C), 205.7 (1C), 221.0
(2C) (CO) ppm. IR: nCO ¼ 2009.8 (vs), 1888.3 (vs), 1855.5 (vs), 1818.9
(vs) cmꢀ1. Anal. Calc. for C21H19ClMoN4O4: C, 48.25; H, 3.66; N,
10.72. Found: C, 48.24; H, 3.39; N, 10.82%.
J ¼ 7.2 Hz, 1H), 7.12 (t, J ¼ 7.1 Hz, 1H), 7.33 (d, J ¼ 7.1 Hz, 1H), 7.95 (d,
J ¼ 7.2 Hz, 1H) (C6H4), 7.62 (s, 1H, CH) ppm. 13C NMR (DMSO-d6):
d
10.7, 16.0 (CH3), 71.0 (CH), 108.0 (C4 of pyrazole), 124.0, 128.1,
129.4, 135.5, 141.6, 157.0 (C6H4), 142.1, 152.4 (C3 and C5 of pyrazole),
233.1 (CO) ppm. IR: nCO ¼ 2008.2 (vs), 1926.5 (vs), 1896.3 (vs) cmꢀ1
.
Anal. Calc. for C20H19BrN4O3W: C, 38.30; H, 3.05; N, 8.93. Found: C,
38.45; H, 3.35; N, 8.83%.
3.7. Synthesis of (2-ClC6H4)CH(3,5-Me2Pz)2W(CO)4 (7)
This complex was obtained similarly using compound 2 instead
of compound 1 as described above for 5. The eluent was CH2Cl2/
3.11. Heating complex 8 in THF
hexane (1/1 v/v). Yield: 35%. 1H NMR (acetone-d6):
d
2.41, 2.53 (s, s,
The solution of complex 8 (0.10 g, 0.15 mmol) in THF (30 ml) was
stirred and heated at reflux for 24 h. The solvent was removed
under reduced pressure, the residual solid was purified by column
chromatography on silica using ethyl acetate/hexane (1/1 v/v) as
eluent to give complex 10 as a yellowegreen solid. Yield: 80 mg
(85%).
6H, 6H, CH3), 6.20 (s, 2H, H4 of pyrazole), 6.01 (d, 1H, J ¼ 7.8 Hz),
7.14e7.27 (m, 3H) (C6H4), 7.84 (s, 1H, CH) ppm. 13C NMR (acetone-
d6):
d
12.1, 17.4 (CH3), 69.1 (CH), 109.1 (C4 of pyrazole), 129.2, 129.8,
132.2, 132.5, 132.6, 133.3 (C6H4), 145.9, 156.8 (C3 and C5 of pyrazole),
201.5 (1C), 205.0 (1C), 212.8 (2C) (CO) ppm. IR: nCO ¼ 2002.4 (s),
1879.3 (vs), 1846.8 (vs), 1817.3 (vs) cmꢀ1
. Anal. Calc. for
C21H19ClN4O4W.0.25CH2Cl2: C, 40.39; H, 3.11; N, 8.87. Found: C,
40.57; H, 3.23; N, 9.13%.
3.12. Synthesis of (2-ImC6H4)CH(3,5-Me2Pz)2 (11) (Im ¼ imidazol-
1-yl)
3.8. Synthesis of (2-BrC6H4)CH(3,5-Me2Pz)2W(CO)4 (8)
The solution of compound 3 (0.72 g, 2.0 mmol) imidazole (0.16 g,
2.4 mmol), CuI (0.1 g, 0.52 mmol), anhydrous Cs2CO3 (1.64 g,
The solution of compound 3 (0.11 g, 0.31 mmol) and W(CO)6
(0.11 g, 0.31 mmol) in THF (30 ml) was irradiated with a 300 W
high-pressure mercury lamp for 8 h at room temperature. The
solvent was removed under reduced pressure, and the residue was
purified by column chromatography on silica using CH2Cl2/hexane
(2/1 v/v) as eluent. The greeneyellow eluate was concentrated to
dryness, the residue was recrystallized from CH2Cl2/hexane to give
greeneyellow solids of 8. Yield: 0.10 g (49%). 1H NMR (acetone-d6):
5.0 mmol) and L-proline (0.12 g,1.0 mmol) in DMF (5 ml) was stirred
and heated at 120 ꢁC for 24 h. After cooling to room temperature,
water (100 ml) was added to the above-mentioned solution. The
aqueous solution was extracted with ethyl acetate (3 ꢂ 100 ml). The
organic layers were combined and dried over anhydrous MgSO4.
The solvent was removed under reduced pressure, the residual oil
was purified by column chromatography on silica. First, an ethyl
acetate/hexane (1/1 v/v) mixture was used as eluent to remove the
starting materials, then an ethyl acetate/methanol (5/1 v/v)
d
2.42, 2.54 (s, s, 6H, 6H, CH3), 6.20 (s, 2H, H4 of pyrazole), 5.98 (d,

94
D.-W. Zhao et al. / Journal of Organometallic Chemistry 718 (2012) 89e95
mixture was used as eluent to give a yellow eluate. After removing
of W(CO)6 (0.18, 0.50 mmol) in THF (40 ml) with a 300 W high-
pressure mercury lamp for 8 h, and the reaction mixture was stir-
red and heated at reflux for 5 h. The solvent was removed under
reduced pressure, and the residue was purified by column chro-
matography on silica using CH2Cl2 as eluent. The green-yellow
eluate was concentrated to dryness, and the residue was recrys-
tallized from CH2Cl2/hexane to give green-yellow crystals of 13.
the solvents, compound 11 was obtained as a slightly yellow solid.
Yield: 0.24 g (35%), mp 136e137 ꢁC. 1H NMR:
d 1.86, 2.14 (s, s, 6H,
6H, CH3), 5.82 (s, 2H, H4 of pyrazole), 6.63 (s, 1H, C6H4), 7.04e7.11
(m, 4H), 7.24 (s, 1H), 7.44 (s, br, 2H) (C6H4, CH and protons of
imidazole) ppm. 13C NMR:
d
9.6, 12.6 (CH3), 68.9 (CH), 106.2 (C4 of
pyrazole), 119.2, 126.5, 127.8, 128.3, 128.6, 132.4, 134.5, 136.5 (C6H4
as well as carbons of imidazole), 139.2, 147.5 (C3 and C5 of pyrazole)
ppm. HRMS (ESI, m/z): 369.1793 (Calcd for C20H22N6Na: 369.1798,
[M þ Na]þ, 100%).
Yield: 0.12 g (32%). 1H NMR:
d 1.87 (s, 3H), 2.04 (s, 3H), 2.21 (s, 3H),
2.31 (s, 3H) (CH3), 5.37 (d, J ¼ 15.1 Hz, 1H), 5.67 (d, J ¼ 15.1 Hz, 1H)
(CH2), 5.67, 5.84 (s, s, 1H, 1H, H4 of pyrazole), 6.12 (d, J ¼ 1.9 Hz, 1H),
6.64 (d, J ¼ 1.9 Hz, 1H) (protons of imidazole), 7.29e7.45 (m, 6H),
7.55e7.60 (m, 3H) (C6H4 and C6H5), 7.03 (s, 1H, CH) ppm. 13C NMR:
3.13. Synthesis of [PhCH2(2-Im)C6H4]CH(3,5-Me2Pz)2(Cl) (12)
d
11.2, 11.3, 13.6, 14.0 (CH3), 57.1 (CH2), 68.3 (CH), 106.6, 107.1 (C4 of
pyrazole), 120.9, 123.5 (carbons of imidazole), 127.9, 128.5, 129.1,
129.7 (C6H5), 130.1, 130.4, 130.5, 134.7, 135.7, 139.6 (C6H4), 139.2,
139.9, 147.8, 149.5 (C3 and C5 of pyrazole), 182.0 (CNHC), 198.1 (4C),
200.3 (1C) (CO) ppm. These assignments were confirmed by stan-
dard Bruker gradient enhanced HMBC and HMQC pulse sequences.
IR: nCO ¼ 2060.0 (m), 1965.5 (vs), 1926.9 (vs), 1901.8 (vs), 1882.5 9
(vs) cmꢀ1. Anal. Calc. for C32H28N6O5W: C, 50.54; H, 3.71; N, 11.05.
Found: C, 50.41; H, 3.22; N, 11.06%.
The solution of compound 11 (0.41 g, 1.18 mmol) and PhCH2Cl
(0.15 g, 1.18 mmol) in CH3CN (40 ml) was stirred and heated at
reflux for 24 h. After cooling to room temperature, the solution was
concentrated to approximately 5 ml under reduced pressure and
20 ml of dry ethyl ether was slowly added. After standing at 4 ꢁC
overnight, a brown precipitate was formed, which was filtered off
and washed with ethyl ether to give compound 12. Yield: 0.50 g
(90%), mp 112e114 ꢁC. 1H NMR:
d 1.99, 2.03 (s, s, 6H, 6H, CH3), 5.48
(s, 2H, CH2), 5.76 (s, 2H, H4 of pyrazole), 6.65 (d, J ¼ 4.8 Hz, 1H,
C6H4), 7.44e7.54 (m, 5H, C6H4 and protons of imidazole), 7.63e
7.71 (m, 3H), 7.94e8.05 (m, 2H) (C6H5), 7.80 (s, 1H, CH), 10.08 (s,
3.15. Synthesis of complex 14
1H, proton of imidazole) ppm. 13C NMR:
d 10.7, 13.2 (CH3), 51.8
3.15.1. Method A
(CH2), 69.5 (CH), 106.6 (C4 of pyrazole), 122.2, 123.8, 128.2, 128.3,
128.6, 128.7, 128.8, 130.2, 131.0, 132.5, 133.0, 134.3, 137.1, 140.3, 147.6
(C6H4, C6H5, C3 and C5 of pyrazole as well as carbons of imidazole)
ppm. HRMS (ESI, m/z): 437.2443 (Calcd for C27H29N6: 437.2448,
[MeCl]þ, 100%).
The mixture of compound 12 (0.22 g, 0.47 mmol) and Ag2O
(0.11 g, 0.47 mmol) in CH2Cl2 (20 ml) was stirred at room temper-
ature for 24 h. The resulted solution was filtered and concentrated
to dryness. Then the residue was added to the solution of Ru3(CO)12
(0.30 g, 0.47 mmol) in THF (40 ml), and the reaction mixture was
stirred and heated at reflux for 3 h. The solvent was removed under
reduced pressure, and the residue was purified by column chro-
matography on silica. First, hexane was used as eluent to give
Ru3(CO)12, then CH2Cl2 as eluent to yield red-orange solids of
3.14. Synthesis of complex 13
The mixture of compound 12 (0.24 g, 0.50 mmol) and Ag2O
(0.12 g, 0.50 mmol) in CH2Cl2 (20 ml) was stirred at room
temperature for 24 h. The solution was filtered off and concentrated
to dryness. Then, the residue was added to the solution of
W(CO)5THF in THF, prepared in situ by the irradiation of a solution
complex 14. Yield: 70 mg (15%). 1H NMR:
d
ꢀ11.3 (s, 1H, RuH), 1.61
(s, 3H), 1.66 (s, 3H), 2.02 (s, 3H), 2.65 (s, 3H) (CH3), 5.65 (m, 2H)
(CH2), 5.62, 6.06 (s, s, 1H, 1H, H4 of pyrazole), 6.51 (d, J ¼ 1.3 Hz, 1H),
6.61 (d, J ¼ 1.3 Hz,1H) (protons of imidazole), 6.79 (d, J ¼ 7.5 Hz,1H),
Table 1
Crystal data and refinement parameters for complexes 7, 10, 13 and 14.
Complex
7
10
13
14
Formula
Formula weight
Crystal size (mm)
C21H19ClN4O4W
610.70
C20H19BrN4O3W
627.15
C32H28N6O5W
760.45
C35H29ClN6O8Ru3
1000.30
0.20 ꢂ 0.20 ꢂ 0.15
0.24 ꢂ 0.22 ꢂ 0.10
0.20 ꢂ 0.18 ꢂ 0.10
0.24 ꢂ 0.20 ꢂ 0.18
T (K)
293(2)
113(2)
113(2)
113(2)
ꢀ
l
(MoK
a
) (A)
0.71073
Monoclinic
P21/n
10.312(2)
13.937(3)
15.208(3)
90
90.04(3)
90
2185.6(8)
4
1.856
1184
5.443
3.05e27.48
22,842
0.71075
Monoclinic
C2/c
26.79(2)
10.007(7)
16.773(12)
90
113.405(8)
90
4127(5)
8
2.019
2400
7.576
1.66e27.86
20,237
0.71073
Monoclinic
P21/n
12.513(3)
13.334(3)
18.517(4)
90
94.020(5)
90
3082.2(12)
4
1.639
1504
3.798
1.88e27.87
28,927
0.71073
Triclinic
ꢁ
Pı
Crystal system
Space group
ꢀ
a (A)
11.566(3)
16.626(4)
21.954(5)
107.931(3)
98.908(2)
104.869(2)
3754.5(14)
4
1.770
1976
1.321
1.36e27.90
42,190
ꢀ
b (A)
ꢀ
c (A)
a
(ꢁ)
(ꢁ)
b
g
(ꢁ)
3
ꢀ
V (A)
Z
Dc (g cmꢀ3
F(000)
)
m
(mmꢀ1
Range (ꢁ)
)
q
No. of measured reflections
No. of unique reflections (Rint
No. of observed reflections with (I > 2s(I))
)
5008 (0.0532)
4084
4897 (0.055)
3869
7329 (0.0492)
5709
17,614 (0.0454)
12,960
No. of parameters
GOF
284
1.055
266
1.001
401
1.006
971
0.876
Residuals R, Rw
0.0368, 0.0656
0.0337, 0.0765
0.0256, 0.0531
0.0381, 0.0563

D.-W. Zhao et al. / Journal of Organometallic Chemistry 718 (2012) 89e95
95
7.31 (m, 1H), 7.40e7.45 (m, 3H) 7.59e7.69 (m, 4H) (C6H4 and C6H5),
7.08 (s, 1H, CH) ppm. 13C NMR:
10.5, 11.1, 13.4, 14.1 (CH3), 55.6
2012.08.004. These data include MOL files and InChiKeys of the
most important compounds described in this article.
d
(CH2), 68.0 (CH), 106.9, 110.6 (C4 of pyrazole), 119.6, 122.2 (carbons
of imidazole), 127.0, 128.1, 128.5, 129.0 (C6H5), 129.9, 130.4, 130.5,
134.8, 135.3, 139.0 (C6H4), 141.5, 142.6, 146.9, 153.8 (C3 and C5 of
pyrazole), 179.0 (CNHC), 193.2, 193.8, 204.1, 204.7, 205.6, 206.3 (CO)
ppm. IR: nCO ¼ 2072.3 (m), 1999.1 (vs), 1990.3 (vs), 1932.5 (m),
1922.8 (w) cmꢀ1. Anal. Calc. for C35H29ClN6O8Ru3: C, 42.02; H, 2.92;
N, 8.40. Found: C, 41.65; H, 3.12; N, 8.24%.
References
[1] A. Otero, J. Fernández-Baeza, A. Lara-Sánchez, J. Tejeda, L.F. Sánchez-Barba,
Eur. J. Inorg. Chem. (2008) 5309e5326.
[2] C. Pettinari, R. Pettinari, Coord. Chem. Rev. 249 (2005) 663e691.
[3] A. Otero, J. Fernández-Baeza, A. Antiñolo, J. Tejeda, A. Lara-Sánchez, Dalton
Trans. (2004) 1499e1510.
[4] K. Ding, C.-H. Cheng, Y.-X. Yang, H.-B. Song, L.-F. Tang, J. Organomet. Chem.
696 (2011) 3662e3667.
[5] X.-Y. Zhang, X.-L. Liu, H.-B. Song, L.-F. Tang, Chin. J. Chem. 29 (2011) 2702e
2706.
[6] Z.-K. Wen, Y.-F. Xie, S.-B. Zhao, R.-Y. Tan, L.-F. Tang, J. Organomet. Chem. 693
(2008) 1359e1366.
[7] Y.-F. Xie, Z.-K. Wen, R.-Y. Tan, J. Hong, S.-B. Zhao, L.-F. Tang, Organometalllics
27 (2008) 5684e5690.
[8] T.G. Richmond, M.A. King, E.P. Kelson, A.M. Arif, Organometallics 6 (1987)
1995e1996.
[9] T.G. Richmond, C.E. Osterberg, A.M. Arif, J. Am. Chem. Soc. 109 (1987) 8091e
8092.
3.15.2. Method B
The mixture of compound 12 (69 mg, 0.16 mmol) and Ag2O
(38 mg, 0.16 mmol) in THF (30 ml) was stirred at room temperature
for 24 h. Ru3(CO)12 (0.10 g, 0.16 mmol) was added to the resulted
solution, and the reaction mixture was stirred and heated at reflux
for 3 h. After the solvent was removed under reduced pressure, the
residue was purified by the same procedure as shown in method A
to yield red-orange solids of complex 14. Yield: 40 mg (25%).
No reaction took place in the treatment of compound 12 with
Ru3(CO)12 in THF at room temperature. The ligand decomposed
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ꢂ
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Acknowledgements
This work is supported by the National Natural Science Foun-
dation of China (No. 20972075).
Appendix A. Supplementary material
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CCDC 873103, 873104, 873105 and 873106 contain the supple-
mentarycrystallographic data for 7,10,13 and 14, respectively. These
data can be obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
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Appendix B. Supplementary material
Supplementary material associated with this article can be found
in the online version, at http://dx.doi.org/10.1016/j.jorganchem.