M-metallaphenol: Synthesis and reactivity studies

Article abstract of DOI:10.1002/chem.201304957

Treatment of the osmium complex [Os{CHC-(PPh₃)CH(OH)- η²-C≡CH}(PPh₃)₂(NCS)₂] (1) with excess triethylamine produces the first m-metallaphenol complex [Os{CHC(PPh₃)CHC(OH)CH}(PPh₃

Full text of DOI:10.1002/chem.201304957

DOI: 10.1002/chem.201304957
Full Paper
&
Synthesis
m-Metallaphenol: Synthesis and Reactivity Studies
Feifei Han, Tongdao Wang, Jinhua Li, Hong Zhang,* and Haiping Xia*[a]
Abstract: Treatment of the osmium complex [Os-
{CHC-(PPh3)CH(OH)-h2-CꢀCH}(PPh3)2(NCS)2] (1) with excess
triethylamine produces the first m-metallaphenol complex
[Os{CHC(PPh3)CHC(OH)CH}(PPh3)2(NCS)2] (2). The NMR spec-
troscopic and structural data as well as the nucleus-inde-
pendent chemical-shift (NICS) values suggest that osmaphe-
nol 2 has aromatic character. The reactivity studies demon-
strate that 2 can react with different isocyanates to form the
lar annulation reactions can be extended to other unsaturat-
ed compounds containing N–C multiple bonds, for example,
isothiocyanates, pyridine, and sodium thiocyanate, which
can produce the corresponding fused osmabenzene com-
plexes. In contrast, the reactions of 2 with common electro-
philes, such as NOBF4, NO2BF4, N-bromosuccinimide, and N-
chlorosuccinimide only led to the decomposition of the met-
allaphenol ring. The experimental results suggest that 2 is
annulation reaction products [Os{CHC(PPh3)CHC(OÀC= very electrophilic and readily reacts with nucleophiles, which
ONR)C}(PPh3)2(NCS)2] (R=Ph (3), iPr (7), Bn (8)) via the carba-
mate intermediates [Os{CHC(PPh3)CHC(O-C=ONHR)CH}-
is mainly due to the metal center and the strong electron-
withdrawing phosphonium group.
(PPh3)2(NCS)2] (R=Ph (4), iPr (5), Bn (6)). In addition, the simi-
Introduction
example for m-metallaphenols (III) as well as the reactivity
studies of the complex.
As new aromatic heterocycles, metallaaromatics have attracted
considerable attention because of their aromatic properties
and organometallic reactivities.[1] Most studies in this field con-
cern the synthesis and the reactivity study of stable metallaaro-
matics. It is now well established that metallaaromatics can un-
dergo characteristic aromatic reactions, such as electrophilic ar-
omatic substitution (SEAr),[2] nucleophilic aromatic substitution
(SNAr)[3] reactions, and forming half-sandwich,[4a] sandwich,[4b] Results and Discussion
and triple-decker complexes[4c] as h6 ligands. These studies not
Synthesis of m-osmaphenol from [Os{CHC-(PPh3)CH(OH)-h2-
CꢀCH}(PPh3)2(NCS)2] (1)
only provide strong evidence for the aromaticity of these aro-
matic heterocycles, but also allow us to obtain new interesting
organometallic complexes.
Treatment of complex 1 with excess triethylamine in dichloro-
methane led to the formation of complex 2, which can be iso-
lated as a green solid in 80% yield [Eq. (1)]. Complex 2 was
characterized by NMR spectroscopy and elemental analysis,
and the structure was further confirmed by single-crystal X-ray
diffraction.
Since the first examples of stable metallaaromatics, that is,
metallabenzenes, reported in 1982,[5] the synthesis of various
metallaaromatics has been widely investigated.[1] However, the
isolation of metallaphenols, which can be viewed as closely re-
lated derivatives of metallabenzenes, has met with limited suc-
cess.[6] The reported examples of metallaphenols are o-metalla-
phenols (I)[6a,b] and p-metallaphenols (II),[6c,d] in which the hy-
droxyl group takes up a position ortho or para to the transition
metal. In this contribution we present the synthesis of the first
[a] F. Han, Dr. T. Wang, J. Li, Dr. H. Zhang, Prof. Dr. H. Xia
State Key Laboratory of Physical Chemistry of Solid Surfaces
Collaborative Innovation Center of Chemistry for Energy Materials
and College of Chemistry and Chemical Engineering
Xiamen University, Xiamen, 361005 (P. R. China)
E-mail: zh@xmu.edu.cn
The crystallographic details of the osmaphenol complex 2
are given in Table 2. Selected bond lengths and angles are
given in Table 1. As shown in Figure 1, 2 contains a nearly
planar metallabenzene unit and the hydroxyl group is attached
to C4 of the metallacycle. The mean deviation from the least-
squares plane through Os1 and C1ÀC5 is 0.0632 ꢀ, and the
hpxia@xmu.edu.cn
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/chem.201304957.
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Table 1. Selected bond lengths and angles for 2, 3, and 4.
2
3
4
Bond lengths [ꢀ]
Os1ÀC1
1.975(9)
1.968(9)
1.974(3)
1.941(3)
1.398(4)
1.425(5)
1.358(5)
1.401(5)
Os1ÀC5
1.937(10)
1.385(11)
1.400(13)
1.363(13)
1.422(12)
1.940(10)
1.407(12)
1.425(12)
1.372(13)
1.456(15)
C1ÀC2
C2ÀC3
C3ÀC4
C4ÀC5
Bond angles [8]
C1-Os1-C5
Os1-C1-C2
C1-C2-C3
C2-C3-C4
C3-C4-C5
C4-C5-Os1
89.2(4)
89.5(4)
89.54(13)
128.5(2)
123.0(3)
123.7(3)
125.7(3)
128.0(2)
128.4(7)
123.4(8)
124.6(8)
124.1(9)
127.9(7)
131.6(7)
121.1(8)
121.6(8)
129.7(8)
123.7(6)
Figure 1. Molecular structure of 2. The hydrogen atoms of PPh3 are omitted
for clarity.
sum of angles in the six-membered ring is 717.68, which is
close to the ideal value of 7208. All bond distances within the
metallacycle fall within the range observed for other typical
metallabenzenes.[1] The CÀC bond lengths of the metallaben-
zene ring are in the range of 1.363(13)–1.422(12) ꢀ. The copla-
narity and lack of significant alternations in the CÀC bond
lengths suggests that complex 2 has a delocalized structure.
The CÀO bond lengths (1.396(11) ꢀ) are close to those found
in other metallaphenol systems.[6]
The osmaphenol structure feature is also clearly evident by
1
NMR spectroscopy. In particular, the H NMR (in CD2Cl2) spec-
1
trum shows three H signals of the metallabenzene ring at d=
1
15.8 (C1H), 7.3 (C3H), 17.8 ppm (C5H). With the aid of the H-
13C HSQC and 13C-dept 135 spectra, the five carbon signals of
the metallabenzene ring are observed at d=218.2 (C1), 112.0
(C2), 127.6 (C3), 157.9 (C4), and 247.0 ppm (C5) in the
Table 2. Crystal data and structure refinement for 2, 3, 4, 9, 10, and 11.
2
3
4
9
10
11
formula
C62H51Cl2N2OOsP3S2 C69.5H53.5Cl4.5N3O2OsP3S2 C70.5H58Cl5N3O2OsP3S2 C67H56Cl6N3OOsP3S3 C69.75H53.5Cl8.25F3N3O5OsP3S3 C65H54Cl6N3OOsP3S3
Mw
T [K]
1258.18
173(2)
1469.41
173(2)
1503.68
173(2)
1511.14
150(2)
1742.41
173(2)
1485.10
173(2)
l [ꢀ] (MoKa radia-
0.71073
0.71073
0.71073
0.71073
0.71073
0.71073
tion)
crystal system
space group
a [ꢀ]
b [ꢀ]
c [ꢀ]
monoclinic
P21/n
12.7202(5)
19.1661(6)
22.6788(10)
90
97.868(4)
90
5477.0(4)
4
monoclinic
Cc
19.8039(3)
17.4152(3)
19.7067(3)
90
105.834(2)
90
6538.73(18)
4
triclinic
¯
P1
monoclinic
P21/c
13.5792(3)
18.8412(4)
25.5089(5)
90
92.890(2)
90
6518.1(2)
4
monoclinic
C2/c
47.0317(13)
12.5667(4)
25.0185(5)
90
101.290(2)
90
14500.6(7)
8
monoclinic
P21/c
13.988(2)
24.091(4)
20.018(3)
90
105.434(3)
90
6502.2(18)
4
12.3719(3)
14.9614(3)
18.9487(5)
110.217(2)
90.007(2)
98.467(2)
3250.54(13)
2
a [8]
b [8]
g [8]
V [ꢀ3]
Z
1calcd [gcmÀ3
]
1.526
2.634
2528
1.493
2.319
2948
1.536
2.354
1512
1.540
2.417
3032
1.596
2.275
6954
1.517
2.422
2976
m [mmÀ1
F(000)
]
crystal size [mm3]
q range [8]
total reflns
0.30ꢂ0.20ꢂ0.02
2.75 to 25.00
25265
0.40ꢂ0.20ꢂ0.10
2.90 to 26.37
18253
0.80ꢂ0.60ꢂ0.40
2.94 to 25.00
26222
0.60ꢂ0.40ꢂ0.20
2.97 to 25.00
28974
0.80ꢂ0.60ꢂ0.20
2.65 to 26.38
38265
0.20ꢂ0.20ꢂ0.15
1.35 to 25.00
32640
unique reflns
observed reflns
[Iꢁ2s(I)]
9621
7181
10792
10154
11427
10622
11477
10119
14807
11808
11429
9966
data/restraints/pa-
rameters
9621/78/677
10792/116/821
11427/120/821
11477/204/831
14807/514/995
11429/90/786
GOF on F2
1.000
1.000
1.000
1.000
1.000
1.000
R1/wR2 [Iꢁ2s(I)]
R1/wR2 (all data)
largest peak/hole
0.0656/0.1399
0.0961/0.1538
2.077/À1.791
0.0408/0.1094
0.0451/0.1252
1.411/À0.989
0.0276/0.0647
0.0315/0.0662
0.753/À1.256
0.0447/0.0996
0.0527/0.1032
1.926/À1.757
0.0553/0.1375
0.0734/0.1498
2.239/À1.332
0.0350/0.0871
0.0413/0.0897
1.522/À0.683
[eꢀÀ3
CCDC no.
]
935257
935258
964601
935261
935262
974941
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13C{1H} NMR spectrum. The presence of a hydroxyl
substituent is supported by the chemical shifts in the
1H NMR spectrum (d=3.6 ppm).
Similar to our previously reported mechanism for
the formation of osmabenzene [(SCN)2(Ph3P)2Os{CHC-
(PPh3)CHC(SCN)CH}] from complex 1,[7b] the formation
of osmaphenol may also involve the nucleophilic ad-
dition and elimination process. As shown in
Scheme 1, 1 could undergo intermolecular nucleo-
philic addition with the H2O present in solution to
give the O-protonation intermediate A. Subsequent
elimination of H2O could produce osmaphenol 2. It is
possible that a trace amount of water in solution ini-
tiates the reaction. When the reaction was carried out
in the presence of purposely introduced H2O, the
conversion of 1 was complete within two days and
gave 2 as the major product. Besides, the addition of
excess triethylamine may facilitate the dehydration of
intermediate A.
Scheme 2. Relative energies and the calculated NICS(1) values (ppm) of osmaphenols.
stable than the ortho isomer o5-osmaphenol, which is the
most unstable for the thiocyanate-substituted species. There-
fore, we speculate that the strong SCN ligands play important
roles in the stability of osmaphenols 2. Consistent with our cal-
culation results, the formation of analogue m-osmaphenol
could not be observed when the reaction was performed with
starting material [Os{CHC(PPh3)CH(OH)-h2-CꢀCH}Cl2(PPh3)2],[7a]
that is, the chloride-substituted derivative of 1, under the same
conditions.
Scheme 1. Plausible mechanism for the formation of osmaphenol 2.
Reactions of the osmaphenol complex 2 with phenyl isocya-
nate
It is worth mentioning that complex 2 can be viewed as the
first m-metallaphenol (III). In addition, the osmaphenol com-
plex 2 exhibits notable stability under an air atmosphere. After
being kept for months at room temperature, it remains nearly
unchanged both in the solid state and in solution. Complex 2
also has remarkable thermal stability. A solid sample of 2 could
be heated at 1008C for at least five hours without noticeable
decomposition.
Since the formation of the urethane linkage from the isocya-
nates and phenols is one of the most characteristic chemical
reactions of phenols, we initially studied the reactivity of 2
with phenyl isocyanate. As shown in Scheme 3, treatment of 2
with excess phenyl isocyanate in dichloromethane in the pres-
ence of triethylamine led to the formation of the complex 3,
which can be isolated as a green solid in 85% yield.
DFT calculations were carried out to evaluate the aromaticity
related to the metallaphenols. The optimized structure of the
model complex 2 reproduces well the structural features of 2
described above. The nucleus-independent chemical shift
(NICS) values were computed for the metallaphenol rings. As
shown in Scheme 2, the calculated NICS(1) values of 2 are
À3.6 ppm. The values are comparable to other metallaphenol
model complexes and those reported for other metallaaromat-
ics.[8] The calculated negative NICS values indicate aromaticity
associated with the metallaphenol ring in complex 2.
Model DFT computations also provided estimates of the rela-
tive energies of the different osmaphenols. As shown in
Scheme 2, the model complex 2’, in which SCN substituents
were replaced by Cl substituents, is the most unstable for the
chloride-substituted osmaphenols, whereas complex 2 is more
Scheme 3. Reactions of osmabenzene 2 with phenyl isocyanate.
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Complex 3 has been characterized by single-crystal X-ray dif-
fraction. Selected bond lengths and angles are given in
Table 1, and the crystallographic details are given in Table 2.
The molecular structure of 3 is shown in Figure 2, which con-
firms that 3 is a fused metallabenzene complex, that is, metal-
Table 3. Selected NMR spectroscopic data for the carbamate complexes
4, 5, and 6.
Compound d (1 H) [ppm]
H1 H3 H5
d (13C) [ppm]
C1 C2
C3
C4
C5
4
5
6
16.9 7.7 17.5 229.0 112.2 141.5 151.1 244.7
16.6 7.6 17.5 228.3 111.9 141.0 151.4 246.3
16.7 7.6 17.5 228.6 112.1 141.1 151.5 245.8
Figure 2. Molecular structure of 3. The hydrogen atoms of PPh3 are omitted
for clarity.
labenzoxazolone. Due to the fused five-membered ring, the
metallabenzene ring of 3 deviates slightly from planarity, as re-
flected by the mean deviation from the least-squares plane
through Os1 and C1ÀC5 (0.0699 ꢀ). The C4ÀC5 bond length
(1.456 ꢀ) is in the high end of the observed range for the typi-
cal metallabenzenes (1.316–1.472 ꢀ).[9] Consistent with the
Figure 3. Molecular structure of 4. The hydrogen atoms of PPh3 are omitted
for clarity.
structure clearly shows that complex 4 contains an essentially
planar metallabenzene ring substituted with
linkage.
a urethane
1
solid-state structure, the H and 13C NMR spectroscopic chemi-
cal shifts of the six-membered ring atoms in complex 3 appear
in the aromatic region. The 1H NMR spectrum displayed the
OsCH signal at d=15.9 ppm and the OsCHC(PPh3)CH signal at
d=7.4 ppm. The 13C{1H} NMR spectrum showed the five
carbon signals of the metallabenzene ring at 230.8 (C1), 105.6
(C2), 122.2 (C3), 147.1 (C4), and 203.9 ppm (C5). The
31P{1H} NMR spectrum showed two singlets at 15.1 (CPPh3) and
À9.7 ppm (OsPPh3).
As indicated by the in-situ NMR spectrum, the expected con-
version of 4 to the final cyclization product 3 can be observed,
when a mixture of 4 and excess triethylamine in CH2Cl2 was
stirred at room temperature for four days (Scheme 3). The con-
version strongly suggests that the carbamate derivative 4 is
the key intermediate for the transformation of osmaphenols 2
to osmabenzoxazolone 3. Similar annulation reactions of met-
allabenzenes by intramolecular SNAr reactions have been dem-
onstrated.[3d,10] Thus we envisioned that the reactivity study of
the hydroxyl group in osmaphenols 2 may afford other annula-
tion reactions to achieve new fused metallaaromatics
complexes.
On the basis of the above observations, we supposed that
phenyl isocyanate may react with osmaphenol 2 to form the
corresponding carbamate derivative, which then converts to
osmabenzoxazolone 3 by the intramolecular SNAr reaction. As
illustrated in Scheme 3, the conjectural carbamate intermediate
4 can be separated from the reaction as a green solid in 94%
yield by shortening the reaction time. Complex 4 has been
characterized by NMR spectroscopy and elemental analysis.
Extension of the chemistry-annulation reactions of the os-
maphenol complex 2
1
The resonances of the osmabenzene ring in the H (d=16.9
Using different isocyanates, we carried out analogous annula-
tion reactions and observed similar results. Thus the reaction
of 2 with isopropyl isocyanate produced the expected carba-
mate product 5, which can be converted to the corresponding
isopropyl-substituted osmabenzoxazolone 7 in the presence of
excess lithium diisopropylamide (LDA). Similarly, the carbamate
product 6 was obtained from the reaction of 2 with benzyl iso-
cyanate, which was transformed to yield benzyl-containing os-
mabenzoxazolone 8 (Scheme 4). These complexes have been
(C1H), 7.7 (C3H), and 17.5 ppm (C5H)) and 13C{1H} NMR spectra
(d=229.0 (C1), 112.2 (C2), 141.5 (C3), 151.1 (C4), and
244.7 ppm (C5)) are very close to those observed for the osma-
phenol complex 2 (Table 3). The presence of the urethane
1
moiety is evident by the chemical shifts in the H (d=6.6 ppm
(NH)) and 13C{1H} NMR spectrum (d=153.5 ppm (C=O)). The
structure of 4 has been further confirmed by an X-ray diffrac-
tion study, and a view of 4 is shown in Figure 3. The X-ray
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Scheme 4. Reactions of the osmabenzene complex 2 with other isocyanates.
characterized by NMR spectroscopy and elemental analysis. As
shown in Table 3, the complexes 5 and 6 must have a structure
similar to that of 4 as indicated by the similarity in their NMR
spectroscopic data. Due to their low solubility in common or-
ganic solvents, the attempt to obtain the full NMR spectrosco-
py characterization of the complexes 7 and 8 failed. Fortunate-
ly, we get the single crystals of 7 and 8, making it possible to
determine their solid-state structure. The crystallographic de-
tails are given in Table S1 in the Supporting Information. Se-
lected bond lengths and angles are given in Table 4. The X-ray
diffraction study reveals that 7 and 8 are the annulation reac-
tion products, which are structurally similar to osmabenzoxazo-
lone 3.
Scheme 5. Other annulation reactions of the osmabenzene complex 2.
MA=maleic anhydride.
Table 4. Selected bond lengths and angles for 7, 8, 9, and 10.
7
8
9
10
Bond lengths [ꢀ]
Os1ÀC1
2.003(4)
1.957(4)
1.367(6)
1.431(6)
1.341(6)
1.436(6)
1.414(5)
1.365(6)
1.402(5)
1.379(6)
1.996(3)
1.965(3)
1.383(5)
1.436(5)
1.348(5)
1.438(5)
1.411(4)
1.361(4)
1.391(4)
1.388(4)
1.993(5)
1.974(5)
1.382(8)
1.422(7)
1.350(8)
1.412(8)
1.402(6)
1.339(8)
1.403(7)
1.375(8)
1.965(6)
1.976(6)
1.392(8)
1.399(8)
1.375(9)
1.402(9)
1.404(8)
1.327(8)
1.437(8)
1.357(9)
Os1ÀC5
C1ÀC2
C2ÀC3
C3ÀC4
Figure 4. Molecular structure of 9. The hydrogen atoms of PPh3 are omitted
for clarity.
C4ÀC5
C4ÀO1
C6ÀO1
C5ÀN1
C6ÀN1
with the fused metallabenzene ring are similar to those of 3, 7,
and 8. The solution NMR spectroscopic data is fully consistent
with the solid-state structure, which are all in accord with the
osmabenzooxazolethione formulation and comparable to
Bond angles [8]
C1-Os1-C5
Os1-C1-C2
C1-C2-C3
C2-C3-C4
C3-C4-C5
C4-C5-Os1
C5-C4-O1
C4-O1-C6
O1-C6-N1
C5-N1-C6
C4-C5-N1
88.94(17)
130.6(3)
122.0(4)
122.0(4)
129.8(4)
123.2(3)
110.9(4)
106.1(3)
108.8(4)
112.0(4)
101.8(4)
89.48(13)
130.0(2)
122.6(3)
121.9(3)
129.6(3)
123.5(2)
110.9(3)
106.2(3)
108.4(3)
112.1(3)
101.8(3)
89.0(2)
87.7(2)
130.2(4)
122.1(5)
121.8(5)
130.5(5)
122.9(4)
110.3(5)
107.5(5)
108.2(5)
111.5(5)
102.2(5)
133.2(5)
121.8(5)
121.5(6)
129.4(6)
126.2(5)
112.2(5)
106.0(5)
110.4(6)
110.7(5)
100.8(5)
1
those of complex 3 (Table 5). For example, the H NMR spec-
trum of 9 shows the metallabenzene ring signal at d=16.7
and 7.4 ppm (Table 5). The 13C signals of the metallabenzene
ring were observed at 232.0 (C1), 106.9 (C2), 123.2 (C3), 150.8
1
(C4) and 204.4 ppm (C5) with the aid of the 13C{1H} NMR, H-13C
HMBC, and the 13C-dept 135 spectrum. The 31P{1H} NMR spec-
trum shows two signals at d=À6.3 and 15.7 ppm.
To further study the annulation reaction of the osmaphenol
complex 2, we also investigated its reactivities with other unsa-
turated compounds containing the N=C double bond. As
shown in Scheme 5, isothiocyanates can also react with 2 simi-
larly. Thus, the reaction of 2 with isopropyl isothiocyanate gave
the structurally similar complex 9 (Scheme 5). The structure of
complex 9 has been confirmed by an X-ray diffraction study
(Figure 4). Overall, the structural parameters of 9 associated
Table 5. Selected NMR spectroscopic data for the fuse metallabenzene
complexes 3, 9, and 10.
Compound
d (1 H) [ppm]
d (13C) [ppm]
C1 C2
H1
H3
C3
C4
C5
3
9
10
15.9
16.7
20.4
7.4
7.4
8.7
230.8 105.6
232.0 106.9
242.7 117.2
122.2 147.1
123.2 150.8
140.7 151.8
203.9
204.4
178.6
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Notably, the chemistry can even be extended to using pyri-
dine as the starting materials. Treatment of osmaphenol 2 with
trifluoromethanesulfonic anhydride at 08C in pyridine gave rise
to a brown solution. A pure sample of compound 10 can be
obtained as an orange solid from the reaction mixture by
column chromatography in 30% yield. The structure of 10 has
been determined by an X-ray diffraction study, and selected
bond lengths and angles are given in Table 4. As shown in
Figure 5, complex 10 contains an essentially planar polycyclic
Scheme 6. Proposed mechanism for the annulation reactions of the osma-
phenol complex 2.
tions of the osmaphenol complex 2. For isocyanates or isothio-
cyanates, osmaphenol 2 can undergo characteristic nucleophil-
ic addition reactions to form intermediate A. This step is fully
proven by the isolation and the characterization of the com-
plexes 4, 5, and 6. Then, nucleophilic addition of the urethane
linkage at the C5-position of metallabenzene ring may result in
formation of the sH adduct B. Subsequent dehydration reac-
tions of B in the presence of oxygen can yield the fused metal-
labenzene derivatives 3, 7, 8, or 9. For pyridine, a similar reac-
tion of the hydroxyl group of 2 leads to the formation of the
intermediate C, which can also undergo the intermolecular
SNAr reaction to generate the polycyclic intermediate E by in-
termediate D. With the aid of trifluoromethanesulfonic anhy-
dride, deprotonation of the azacycle of E restores the aromatic
pyridine ring, affording the final product 10.
Figure 5. Molecular structure of 10. Counteranion and the hydrogen atoms
of PPh3 are omitted for clarity.
metallacycle unit. The mean deviation from the least-squares
plane through metallabenzene ring (Os1 and C1–C5) is
0.0173 ꢀ, and the maximum deviation from the least-squares
plane through all six atoms is À0.0325 ꢀ for C5. It is interesting
that even the thirteen atoms (Os1, C1–C10, N1, and O1) of the
three rings are approximately coplanar, which is reflected by
the small mean deviation (0.0204 ꢀ) from the least-squares
plane. Besides, the Os1ÀC1 bond length (1.965(6) ꢀ) is very
close to the Os1ÀC5 bond length (1.976(6) ꢀ). The ring C–C
distances of the metallacycle are in the range of 1.375(9)–
1.402(9) ꢀ, which are intermediate between single and double
carbon–carbon bonds. The structural data together with its
planar nature indicate that 10 has a delocalized structure. Con-
Other reactions of the osmaphenol complex 2
In general, phenol is highly reactive toward electrophiles to
undergo SEAr reactions due to the strong electron donation
effect of hydroxyl. To further compare the similarity of metalla-
phenol and phenol, reactivity of osmaphenol 2 was also tested
against a number of electrophiles. As indicated by in situ NMR
spectra, the reactions of 2 with common electrophiles, such as
NOBF4, NO2BF4, N-bromosuccinimide, and N-chlorosuccinimide,
only led to the decomposition of the metallaphenol ring,
giving the unidentified species at room temperature. In addi-
tion, osmaphenol 2 is reactive towards pyridinium tribromide
although we have failed to isolate or identify the expected
SEAr product from the reaction mixtures. As suggested by NMR
spectroscopy (in CD2Cl2), reaction of 2 with pyridinium tribro-
mide produces a mixture of the complex 11 and the complex
12a in a molar ratio of 3:2 at room temperature (Eq. (2)). The
1H NMR spectrum of the mixture shows two sets of characteris-
tic signals of OsCH (d=16.9 and 16.7 ppm) and NH (d=9.7
and 9.7 ppm). The 31P{1H} NMR spectrum shows two OsPPh3
signals at d=À8.6 and À12.5 ppm and two CPPh3 signals at
d=20.4 and 20.0 ppm. The two sets of signals are similar to
those of the fused metallabenzene rings described above.
1
sistent with the solid-state structure, the H and 13C NMR spec-
troscopic chemical shifts of the metallacycle atoms appear in
the aromatic region. As shown in Table 5, the 1H NMR spec-
trum displays the OsCH signal at d=20.4 ppm and the g-CH
1
signal at d=8.7 ppm. On the basis of the 13C{1H} NMR, H-13C
1
HSQC, H-13C HMBC, and 13C-dept 135 spectra, the five carbon
signals of the metallacycle are identified at 242.7 (C1), 117.2
(C2), 140.7 (C3), 151.8 (C4) and 178.6 ppm (C5), respectively.
Mechanistic consideration for the annulation reactions of
the osmaphenol complex 2
Based on above experimental observations, we postulate a re-
action mechanism shown in Scheme 6 for the annulation reac-
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to facilitate the intermolecular SNAr reaction step. To test this
idea, we also studied the conversion in the presence of differ-
ent oxidants. As suggested by in situ NMR spectroscopy, 2 is
unreactive towards Ag2O while the decomposition of the os-
maphenol ring was observed when the reaction was per-
formed with the oxidant H2O2. Similar conversion can be ach-
ieved when the osmaphenol complex 2 was allowed to react
with FeCl3 (Eq. (2)). The reaction produced the expected annu-
lation products 11 and 12b in a molar ratio of 1:3. Supporting
evidence for the existence of the two products is the similarity
in the NMR spectroscopic (in CD2Cl2) data. The two products
exhibit the OsPPh3 signals at d=À8.6 and À7.5 ppm and the
CPPh3 signals at d=20.4 and 20.1 ppm in the 31P{1H} NMR
spectrum. The signals at d=16.9 and 16.0 ppm are assignable
to OsCH protons of the osmabenzene rings in the 1H NMR
spectrum. The molecular structure of 12b has been confirmed
by X-ray diffraction. Selected bond distances and angles are
given in Table S2 in the Supporting Information.
Our attempts to separate the products by recrystallization or
column chromatography were unsuccessful due to the similari-
ty of the two products. Fortunately, after recrystallization of
the crude reaction mixture from CH2Cl2/hexane, a single crystal
of 11 was obtained, making it possible to determine its solid-
state structure. The crystallographic details are given in
Table 2. The X-ray diffraction study reveals that 11 is an osma-
benzooxazolethione complex (Figure 6). The bond lengths of
In view of the reactivity study results, we consider that the
metal center and the strong electron-withdrawing phosphoni-
um group might play a more important role than the hydroxyl
in osmaphenol 2, and therefore 2 is very electrophilic and
readily reacts with nucleophiles.
Conclusion
In summary, the first example of m-metallaphenol has been
synthesized and fully characterized. Both experimental and
theoretical studies suggest that its metallacycle has an aromat-
ic character. It can undergo typical reactions of aromatic sys-
tems (e.g. nucleophilic substitution reactions) as well as phe-
nols (e.g. formation of urethane linkages with isocyanates). Fur-
ther advances in the chemistry of this novel metallaaromatic
compound are expected especially in the study of its proper-
ties and applications.
Figure 6. X-ray structure of complex 11 (ellipsoids at the 50% probability
level). Some of the hydrogen atoms are omitted for clarity. Selected bond
distances [ꢀ] and angles [8]: Os1ÀC1 1.981(4), Os1ÀC5 1.944(3), C1ÀC2
1.380(5), C2ÀC3 1.432(5), C3ÀC4 1.353(5), C4ÀC5 1.412(5), C4ÀO1 1.409(4),
C6ÀO1 1.344(5), C6ÀS1 1.635(4), C6ÀN1 1.357(5), C5ÀN1 1.386(5); C1-Os1-C5
88.43(15), C2-C1-Os1 130.8(3), C1-C2-C3 123.4(3), C2-C3-C4 120.9(3), C3-C4-
C5 128.5(4), C4-C5-Os1 127.5(3), C5-C4-O1 109.8(3), C4-O1-C6 107.5(3), O1-
C6-N1 107.4(3), C5-N1-C6 113.4(3), C4-C5-N1 101.9(3).
Experimental Section
General comments
the fused metallabenzene rings compare well with those
found in the complex 9. On the basis of the characterized
structure of 11, we assume the formation of 11 presumably
proceed through the partly decomposition of osmaphenol 2
to release the free SCNÀ, followed by the annulation reaction
of the osmaphenol ring. Thus, the other unseparated product
was supposed to be the ligand substitution product of 11 with
pyridinium tribromide. Consistent with our assumption, when
the reaction was carried out in the presence of excess NaSCN,
complex 11 was exclusively formed, which can be isolated in
81% yield. Besides, the conversion of 2 to 11 doesn’t occur in
the absence of pyridinium tribromide.
All manipulations were carried out at room temperature under a ni-
trogen atmosphere by using standard Schlenk techniques, unless
otherwise stated. Solvents were distilled under nitrogen from
sodium benzophenone (hexane, diethyl ether, and tetrahydrofuran)
or calcium hydride (dichloromethane and triethylamine). The start-
ing material [Os{CHC(PPh3)CH(OH)-h2-CꢀCH}(PPh3)2(NCS)2] (1) was
synthesized by literature procedures.[7b] Column chromatography
was performed on neutral alumina gel (200–300 mesh). NMR spec-
troscopic experiments were performed on a Bruker AV-500 spec-
trometer (1H: 500.2; 13C: 125.8, 31P: 202.5 MHz), or a Bruker AV-300
1
spectrometer (1H: 300.1, 13C 75.5, 31P: 121.5 MHz). H and 13C NMR
spectroscopic chemical shifts are relative to TMS and 31P NMR spec-
troscopic chemical shifts are relative to 85% H3PO4. Elemental anal-
ysis data were obtained on an Elementar Analysen system GmbH
Vario EL III instrument.
According to the above experimental results, we think that
pyridinium tribromide may act as an oxidant in the conversion
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229.0 (br, C1), 153.5 (s, C6), 151.1 (d, J(P,C)=15.1 Hz, C4), 147.3,
143.4 (s, SCN), 141.5 (d, J(P,C)=21.4 Hz, C3), 119.4–138.6 (m, Ph),
112.2 ppm (d, J(P,C)=76.7 Hz, C2); elemental analysis calcd (%) for
C68H54N3O2OsP3S2: C 63.19, H 4.21, N 3.25; found: C 62.72, H 3.92, N
3.44.
Preparation and characterization of complex 2
A
solution of [Os{CHC(PPh3)CH(OH)-h2-CꢀCH}(PPh3)2(NCS)2] (1)
(504 mg, 0.43 mmol) in dichloromethane (15 mL) and triethylamine
(3 mL) was stirred at room temperature for about 12 days to give
a dark-green solution. The volume of the mixture was reduced to
ca. 2 mL under vacuum. Addition of hexane (20 mL) to the residue
produced a green solid. This was then washed with chloroform
(5 mL) and hexane (20 mL) and the product collected by filtration,
Preparation and characterization of complex 5
Isopropyl isocyanate (0.29 mL, 3.0 mmol) was added to a solution
of 2 (355 mg, 0.30 mmol) in dichloromethane (15 mL) and triethyla-
mine (3 mL). The reaction mixture was stirred at room temperature
for about 9 h to give a dark-green solution. The volume of the mix-
ture was reduced to ca. 2 mL under vacuum. Addition of diethyl
ether (20 mL) to the residue produced a dark-green solid. This
solid was washed with chloroform (5 mL) and diethyl ether (20 mL)
to produce a green solid, which was collected by filtration, and
dried under vacuum. Yield: 359 mg, 94%; 1H NMR (500.2 MHz,
CD2Cl2): d=17.5 (s, 1H, C5H), 16.6 (d, J(P,H)=22.0 Hz, 1H, C1H), 7.0–
7.6 (m, 45H, Ph), 7.6 (1H, C3H obscured by the phenyl signals and
confirmed by 1H-13C HSQC), 4.5 (br, 1H, NH), 3.7 (m, 1H, C7H),
1.1 ppm (d, J(P,H)=5.0 Hz, 6H, C8H); 31P{1H} NMR (202.5 MHz,
CD2Cl2): d=19.0 (s, CPPh3), À4.2 ppm (s, OsPPh3); 13C{1H} NMR
1
and dried under vacuum. Yield: 404 mg, 80%; H NMR (500.2 MHz,
CD2Cl2): d=17.8 (s, 1H, C5H), 15.8 (d, J(P,H)=24.0 Hz, 1H, C1H), 7.3
(1H, C3H obscured by the phenyl signals and confirmed by H-13C
1
HSQC), 6.9–7.7 (m, 45H; Ph), 3.6 ppm (s, 1H, OH); 31P{1H} NMR
(202.5 MHz, CD2Cl2): d=18.3 (s, CPPh3), À6.5 ppm (s, OsPPh3);
13C{1H} NMR (125.8 MHz, CD2Cl2 plus 1H-13C HSQC and 13C-dept
135): d=247.0 (br, C5), 218.2 (br, C1), 157.9 (d, J(P,C)=16.4 Hz, C4),
148.8, 142.0 (s, SCN), 121.8–134.8 (m, Ph), 127.6 (d, J(P,C)=22.6 Hz,
C3), 112.0 ppm (d, J(P,C)=75.5 Hz, C2); elemental analysis calcd (%)
for C61H49N2OOsP3S2: C 62.44, H 4.21, N 2.39; found: C 62.19, H
4.53, N 2.35.
Preparation and characterization of complex 3
1
(125.8 MHz, CD2Cl2, plus H-13C HSQC and 13C-dept 135): d=246.3
(br, C5), 228.3 (br, C1), 155.4 (s, C6), 151.4 (d, J(P,C)=16.4 Hz, C4),
147.1, 143.0 (s, SCN), 141.0 (d, J(P,C)=20.1 Hz, C3), 121.6–135.0 (m,
Ph), 111.9 (d, J(P,C)=76.7 Hz, C2), 43.7 (s, C7), 23.7 ppm (s, C8); ele-
mental analysis calcd (%) for C65H56N3O2OsP3S2: C 62.04, H 4.48, N
3.34; found: C 62.24, H 4.42, N 2.98.
Method A: Phenyl isocyanate (0.49 mL, 4.5 mmol) was added to
a solution of 2 (505 mg, 0.43 mmol) in dichloromethane (25 mL)
and triethylamine (5 mL). The reaction mixture was stirred at room
temperature for about 5 days to give a dark-green solution. The
volume of the mixture was reduced to ca. 2 mL under vacuum. Ad-
dition of diethyl ether (20 mL) to the residue produced a dark-
green solid. This solid was washed with chloroform (5 mL) and di-
ethyl ether (20 mL), giving a green solid, which was collected by fil-
tration, and dried under vacuum. Yield: 472 mg, 85%.
Preparation and characterization of complex 6
Benzyl isocyanate (0.26 mL, 2.1 mmol) was added to a solution of 2
(246 mg, 0.21 mol) in dichloromethane (15 mL) and triethylamine
(3 mL). The reaction mixture was stirred at room temperature for
about 15 min to give a dark-green solution. The volume of the
mixture was reduced to ca. 2 mL under vacuum. Addition of dieth-
yl ether (20 mL) to the residue produced a dark-green solid. This
solid was washed with chloroform (5 mL) and diethyl ether (20 mL)
to produce a green solid, which was collected by filtration and
dried under vacuum. Yield: 269 mg, 98%; 1H NMR (500.2 MHz,
CD2Cl2): d=17.5 (s, 1H, C5H), 16.7 (d, J(P,H)=22.5 Hz, 1H, C1H), 7.6
Method B: A solution of 4 (245 mg, 0.19 mmol) in dichloromethane
(15 mL) and triethylamine (3 mL) was stirred at room temperature
for about 4 days to give a green solution. The volume of the mix-
ture was reduced to ca. 2 mL under vacuum. Addition of diethyl
ether (20 mL) to the residue produced a green solid, which was
collected by filtration, washed with diethyl ether (2ꢂ10 mL) and
dried under vacuum. Yield: 216 mg, 88%; 1H NMR (500.2 MHz,
CDCl3): d=15.9 (d, J(P,H)=23.0 Hz, 1H, C1H), 7.4 (d, J(P,H)=10.5 Hz,
1H, C3H), 6.8–7.7 ppm (m, 50H, Ph); 31P{1H} NMR (202.5 MHz,
CDCl3): d=15.1 (s; CPPh3), À9.7 ppm (s, OsPPh3); 13C{1H} NMR
(125.8 MHz, CDCl3 plus 1H-13C HSQC and 13C-dept 135): d=230.8
(br, C1), 203.9 (br, C5), 158.3 (s, C6), 147.1 (d, J(P,C)=16.4 Hz, C4),
145.3, 142.3 (s, SCN), 122.2 (d, J(P,C)=24.0 Hz, C3), 120.9–137.1 (m,
Ph), 105.6 ppm (d, J(P,C)=77.0 Hz, C2); elemental analysis calcd (%)
for C68H52N3O2OsP3S2: C 63.29; H 4.06; N 3.26; found: C 63.34; H
4.41; N 3.27.
1
(1H, C3H obscured by the phenyl signals and confirmed by H-13C
HSQC), 6.9–7.7 (m, 50H, Ph), 5.1 (br, 1H, NH), 4.3 ppm (d, J(H,H)=
5.5 Hz, 2H, C7H); 31P{1H} NMR (202.5 MHz, CD2Cl2): d=19.0 (s,
CPPh3), À4.5 ppm (s, OsPPh3); 13C{1H} NMR (125.8 MHz, CD2Cl2, plus
1H-13C HSQC): d=245.8 (br, C5), 228.6 (br, C1), 156.4 (s, C6), 151.5 (d,
J(P,C)=16.4 Hz, C4), 147.2 and 143.2 (s, SCN), 141.1 (d, J(P,C)=
21.4 Hz, C3), 121.5–139.2 (m, Ph), 112.1 (d, J(P,C)=75.5 Hz, C2),
45.5 ppm (s, C7); elemental analysis calcd (%) for C69H56N3O2OsP3S2:
C 63.43, H 4.32, N 3.22; found: C 63.56, H 4.33, N 3.16.
Preparation and characterization of complex 4
Phenyl isocyanate (0.22 mL, 2.0 mmol) was added to a solution of
2 (235 mg, 0.20 mmol) in dichloromethane (15 mL) and triethyla-
mine (3 mL). The reaction mixture was stirred at room temperature
for about 11 h to give a dark-green solution. The volume of the
mixture was reduced to ca. 2 mL under vacuum. Addition of dieth-
yl ether (20 mL) to the residue produced a dark-green solid. This
solid was washed with chloroform (5 mL) and diethyl ether (20 mL)
to produce a green solid, which was collected by filtration, and
dried under vacuum. Yield: 243 mg, 94%; 1H NMR (500.2 MHz,
CD2Cl2): d=17.5 (s, 1H, C5H), 16.9 (d, J(P,H)=22.5 Hz, 1H, C1H), 7.7
(d, J(P,H)=12.5 Hz, 1H, C3H), 6.9–7.7 (m, 50H, Ph), 6.6 ppm (br, 1H,
NH); 31P{1H} NMR (202.5 MHz, CD2Cl2): d=19.2 (s, CPPh3), À4.5 ppm
(s, OsPPh3); 13C{1H} NMR (125.8 MHz, CD2Cl2): d=244.7 (br, C5),
Preparation and characterization of complex 7
LDA (0.25 mL, 2.0m solution in THF, 0.50 mmol) was added to a so-
lution of 5 (629 mg, 0.50 mmol) in THF (40 mL). The reaction mix-
ture was stirred at room temperature for about 15 min to give
a dark-green suspension. The volume of the mixture was reduced
to about 2 mL under vacuum and was purified by column chroma-
tography (neutral alumina, eluent: dichloromethane/acetone, 50:1)
to give complex 7 as a green solid sequentially. Yield: 503 mg,
1
80%; H NMR (500.2 MHz, CD2Cl2): d=15.5 (d, J(P,H)=23.0 Hz, 1H,
C1H), 6.8–7.7 (m, 46H, Ph, C3H), 4.9 (m, 1H, C7H), 0.4 ppm (d,
J(P,H)=6.6 Hz, 6H, C8H); 31P{1H} NMR (202.5 MHz, CD2Cl2): d=16.2
(s, CPPh3), À7.0 ppm (s, OsPPh3); elemental analysis calcd (%) for
Chem. Eur. J. 2014, 20, 4363 – 4372
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C65H54N3O2OsP3S2: C 62.14, H 4.33, N 3.34; found: C 62.35, H 4.33, N
2.97.
perature for 4 h to give a dark-green solution. The volume of the
mixture was reduced to about 1 mL under vacuum and was puri-
fied by column chromatography (neutral alumina, eluent: dichloro-
methane/acetone, 50:1) to give complex 11 as a green solid. Yield:
259 mg, 81%.
Preparation and characterization of complex 8
LDA (0.25 mL, 2.0m solution in THF, 0.50 mmol) was added to a so-
lution of 6 (650 mg, 0.50 mmol) in THF (40 mL). The reaction mix-
ture was stirred at room temperature for about 15 min to give
a dark-green suspension. The volume of the mixture was reduced
to about 2 mL under vacuum and was purified by column chroma-
tography (neutral alumina, eluent: dichloromethane/acetone, 50:1)
to give complex 8 as a green solid sequentially. Yield: 535 mg,
Method B: A mixture of complex 2 (203 mg, 0.17 mmol), ferric chlo-
ride (83 mg, 0.51 mmol), and sodium thiocyanate (69 mg,
0.85 mmol) in dichloromethane (15 mL) was stirred at room tem-
perature for 4 h to give a dark-green solution. The volume of the
mixture was reduced to about 1 mL under vacuum and was puri-
fied by column chromatography (neutral alumina, eluent: dichloro-
methane/acetone, 50:1) to give complex 11 as a green solid. Yield:
189 mg, 89%; 1H NMR (500.2 MHz, CD2Cl2): d=15.9 (d, J(P,H)=
24.0 Hz, 1H, C1H), 7.3 (1H, C3H obscured by the phenyl signals and
1
82%; H NMR (500.2 MHz, CD2Cl2): d=15.8 (d, J(P,H)=23.0 Hz, 1H,
C1H), 6.6–7.7 (m, 51H, Ph and C3H), 4.6 ppm (s, 2H, C7H);
31P{1H} NMR (202.5 MHz, CD2Cl2): d=17.1 (s, CPPh3), À8.3 ppm (s,
OsPPh3); elemental analysis calcd (%) for C69H54N3O2OsP3S2: C 63.53,
H 4.17, N 3.22; found: C 63.76, H 4.35, N 3.23.
1
confirmed by H-13C HSQC), 8.4 (s, 1H, NH), 6.9–7.7 ppm (m, 45H,
Ph); 31P{1H} NMR (202.5 MHz, CD2Cl2): d=20.1 (s, CPPh3), À7.5 ppm
1
(s, OsPPh3); 13C{1H} NMR (125.8 MHz, CD2Cl2 plus H-13C HSQC and
13C-dept 135): d=226.2 (br, C1), 201.5 (br, C5), 186.7 (s, C6), 150.2 (d,
J(P,C)=18.9 Hz, C4), 144.0, 143.9 (s, SCN), 121.0–134.6 (m, Ph), 122.8
(d, J(P,C)=23.8 Hz, C3), 106.2 ppm (d, J(P,C)=81.3 Hz, C2); elemental
analysis calcd (%) for C62H48N3OOsP3S3: C 60.52, H 3.93, N 3.42;
found: C 60.21, H 4.13, N 3.06.
Preparation and characterization of complex 9
Isopropyl isothiocyanate (0.46 mL, 4.31 mmol) was added to a mix-
ture of 2 (505 mg, 0.43 mmol) and maleic anhydride (422 mg,
4.30 mmol) in dichloromethane (20 mL) and triethylamine (2 mL).
The reaction mixture was stirred at room temperature for about
1 day to give a brown solution. The volume of the mixture was re-
duced to about 2 mL under vacuum and was purified by column
chromatography (neutral alumina, eluent: dichloromethane/ace-
tone 100:1) to give complex 9 as a green solid. Yield: 438 g, 80%;
1H NMR (300.1 MHz, CDCl3): d=16.7 (d, J(P,H)=21.3 Hz, 1H, C1H),
7.4 (d, J(P,H)=11.7 Hz, 1H, C3H), 6.9–7.7 (m, 45H, Ph), 5.2 (m, 1H,
C7H), 0.7 ppm (d, J(P,H)=6.6 Hz, 6H, C8H); 31P{1H} NMR (121.5 MHz,
CDCl3): d=15.7 (s, CPPh3), À6.3 ppm (s, OsPPh3); 13C{1H} NMR
Crystallographic analysis
Crystals suitable for X-ray diffraction were grown from CH2Cl2 solu-
tions layered with hexane for 2, 4, and 11 and from CHCl3 solution
layered with hexane for 3, 9, and 10. The solvent molecules CH2Cl2
in 2, 4, and 11 are disordered and were refined with suitable re-
straints. The solvent molecules CHCl3 in 3 and 9 are disordered
and were refined with suitable restraints. The solvent molecules
CHCl3 and the OTfÀ groups in 10 are disordered and were refined
with suitable restraints. Single-crystal X-ray diffraction data were
collected on an Oxford Gemini S Ultra CCD Area Detector or
a Bruker Apex CCD area detector with graphite-monochromated
MoKa radiation (l=0.71073 ꢀ). All of the Data were corrected for
absorption effects using the multiscan technique. The structures
were solved by direct methods, expanded by difference Fourier
syntheses and refined by full matrix least-squares on F2 by using
Bruker SHELXTL (Version 6.10) program package. Non-H atoms
were refined anisotropically unless otherwise stated. Hydrogen
atoms were introduced at their geometric positions and refined as
riding atoms unless otherwise stated. Further details on crystal
data, data collection, and refinements are summarized in Table 2.
1
(75.5 MHz, CDCl3 plus H-13C HMBC and 13C-dept 135): d=232.0 (br,
C1), 204.4 (br, C5), 184.7 (s, C6), 150.8 (d, J(P,C)=17.1 Hz, C4), 146.0,
141.9 (s, SCN), 123.2 (d, J(P,C)=23.8 Hz, C3), 120.3–137.2 (m, Ph),
106.9 (d, J(P,C)=79.6 Hz, C2), 53.8 (s, C7), 18.2 ppm (s, C8); elemental
analysis calcd (%) for C65H54N3OOsP3S3: C 61.35, H 4.28, N 3.30;
found: C 61.21, H 4.44, N 3.07.
Preparation and characterization of complex 10
Trifluoromethanesulfonic anhydride (77.4 mL, 0.46 mmol) was
added to a solution of 2 (498 mg, 0.42 mmol) in pyridine (25 mL).
The reaction mixture was stirred at 08C for about 30 min to give
a brown solution. Then the volume of the mixture was reduced to
ca. 2 mL under vacuum. Addition of diethyl ether (20 mL) to the
residue produced a brown solid. The solid of the mixture was puri-
fied by column chromatography (neutral alumina, eluent: dichloro-
methane/acetone, 1:1) to give complex 10 as an orange solid.
Yield: 176 mg, 30%; 1H NMR (500.2 MHz, CD2Cl2): d=20.4 (d,
J(P,H)=20.0 Hz, 1H, C1H), 8.7 (d, J(H,H)=13.0 Hz, 1H, C3H), 6.8–8.8
(m, 49H, Ph, Py); 31P{1H} NMR (202.5 MHz, CD2Cl2): d=20.3 (s,
CPPh3), À17.2 ppm (s, OsPPh3); 13C{1H} NMR (125.8 MHz, CD2Cl2 plus
1H-13C HSQC, HMBC and 13C-dept 135): d=242.7 (br, C1), 178.6 (br,
C5), 154.8, 146.6 (s, SCN), 151.8 (d, J(P,C)=18.2 Hz, C4), 140.7 (d,
J(P,C)=21.6 Hz, C3), 110.1–162.5 (m, Ph, Py), 117.2 ppm (d, J(P,C)=
78.0 Hz, C2); elemental analysis calcd (%) for C67H51N3F3O4OsP3S3: C
57.54, H 3.68, N 3.00; found: C 57.65, H 3.81, N 3.09.
Computational details
All structures were optimized at the B3LYP level of density func-
tional theory.[11] In addition, the frequency calculations were per-
formed to confirm the characteristics of the calculated structures
as minima. In the B3LYP calculations, the effective core potentials
(ECPs) of Hay and Wadt with a double-z valence basis set
(LanL2DZ) were used to describe the Os, P, and S atoms, whereas
the standard 6–31G* basis set was used for the C, O, and H atoms
for all the compounds.[12] Polarization functions were added for Os
(z(f)=0.886), P (z(d)=0.34), S (z(d)=0.421), and Cl (z(d)=0.514).[13]
The calculated bond lengths in Scheme 2 using the model system
are consistent with the experimental values, which indicates the re-
liability of our calculations. All the optimizations were performed
with the Gaussian 03 software package.[14]
Preparation and characterization of complex 11
Method A: A mixture of complex 2 (305 mg, 0.26 mmol), pyridinium
tribromide (249 mg, 0.78 mmol), and sodium thiocyanate (104 mg,
1.28 mmol) in dichloromethane (15 mL) was stirred at room tem-
Chem. Eur. J. 2014, 20, 4363 – 4372
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ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
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We thank the 973 Program (2012CB821600), the National Natu-
ral Science Foundation of China (21174115, 21272193,
21332002) and the Natural Science Foundation of Fujian Prov-
ince (No. 2011J05031).
Keywords: annulation
nucleophilic aromatic substitution
synthesis
reactions
·
·
metallaphenols
·
·
reactivity studies
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Received: December 19, 2013
Published online on March 11, 2014
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4372
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim