Synthesis and characterization of an air-stable p-osmaphenol

Article abstract of DOI:10.1021/om7012265

The synthesis and characterization of an air-stable p-osmaphenol and some related complexes are presented.

Full text of DOI:10.1021/om7012265

Organometallics 2008, 27, 309–311
309
Synthesis and Characterization of an Air-Stable p-Osmaphenol
Lei Gong, Yumei Lin, Guomei He, Hong Zhang, Huijuan Wang, Ting Bin Wen,* and
Haiping Xia*
Department of Chemistry, College of Chemistry and Chemical Engineering, and State Key Laboratory for
Physical Chemistry of Solid Surfaces, Xiamen UniVersity, Xiamen 361005, People’s Republic of China
ReceiVed December 7, 2007
Summary: The synthesis and characterization of an air-stable
p-osmaphenol and some related complexes are presented.
Since the first examples of stable metallabezenes (in 1982)
Scheme 1. Synthesis of Osmaphenol 5
1
were reported, as a novel family of organometallics that are
2
consistent with the presence of an aromatic ring system,
metallabenzenes have been of great interest due to their
3
delocalized π-bonding, corresponding aromatic properties, and
4
anticipated physical properties such as NLO behavior. Various
metallabenzenes and related complexes have been reported
5
–8
recently. However, metallaphenols, which would seem to be
an important series of metallabenzene derivants, are still very
*
To whom correspondence should be addressed. Fax: (+86)592-218-
085 (T.B.W.); (+86)592-218-6628 (H.X.). E-mail: chwtb@xmu.edu.cn
T.B.W.); hpxia@xmu.edu.cn.
1) Elliott, G. P.; Roper, W. R.; Waters, J. M. J. Chem. Soc., Chem.
Commun. 1982, 811.
2) Rickard, C. E. F.; Roper, W. R.; Woodgate, S. D.; Wright, L. J.
Angew. Chem., Int. Ed. 2000, 39, 750.
3) For examples: (a) Iron, M. A.; Martin, J. M. L.; Boom, M. E. J. Am.
6
(
(
6i
rare. The o-iridaphenols reported previously by Bleeke et al.
5a
in 1997 and an o-osmaphenol reported by Jia et al. very
recently are the rare stable metallaphenol examples. The
o-ruthenaphenoxide reported in 1995 could be detected by NMR
(
(
Chem. Soc. 2003, 125, 13020. (b) Iron, M. A.; Lucassen, A. C. B.; Cohen,
H.; Boom, M. E.; Martin, J. M. L. J. Am. Chem. Soc. 2004, 126, 11699.
9
at -78 °C but is unstable at -30 °C. Metallaphenoxides and
metallanaphthalene oxides of Ru, Fe, and Re have been proposed
(
4) Karton, A.; Iron, M. A.; Boom, M. E.; Martin, J. M. L. J. Phys.
1
0
as transient intermediates. Roper’s o-osmathiophenol complex
Chem. A. 2005, 109, 5454.
(
5) Examples of osmabenzenes and osmabenzynes: (a) Hung, W. Y.;
is an additional structurally related example, which was
characterized by IR. In this paper, we report a typical air-stable
1
Zhu, J.; Wen, T. B.; Yu, K. P.; Sung, H. H. Y.; Williams, I. D.; Lin, Z.;
Jia, G. J. Am. Chem. Soc. 2006, 128, 13742. (b) Wen, T. B.; Hung, W. Y.;
Sung, H. H. Y.; Williams, I. D.; Jia, G. J. Am. Chem. Soc. 2005, 127, 2856.
osmaphenol bearing a hydroxyl on the para carbon of the metal
atom prepared from a relatively convenient method under mild
conditions.
In our recent work we have developed a convenient route to
prepare some stable metallabenzenes from the readily accessible
HCt CCH(OH)Ct CH (1).
of the osmabenzene [Os(CHC(PPh3)CHC(PPh3)CH)Cl2-
PPh3)2]OH, the key intermediate OsCl2(CHdC(PPh3)-
CH(OH)Ct CH)(PPh3)2 (2) has been isolated successfully. The
intermediate 2, which can be stored as a solid under nitrogen
but is unstable in solution at room temperature, can undergo
some interesting reactions and evolve to the p-osmaphenol here.
Treatment of a suspension of 2 in dichloromethane with acetic
acid for about 4 h led to the precipitation of a red solid with
poor solubility, which could be isolated in 90% yield and was
identified to be 3 (Scheme 1).
Figure 1 shows the structure of a single crystal of complex
determined by X-ray diffraction. In the structure, Os(1), C(1),
C(2), C(3), and C(4) are almost coplanar, which is reflected by
the deviation (0.028 Å) from the rms planes of the best fit, while
C(5) deviates out of the ring, together with C(4), constituting a
terminal alkene double bond coordinated to the metal center.
The dihedral angle between the five-membered ring and the
(
c) Wen, T. B.; Ng, S. M.; Hung, W. Y.; Zhou, Z. Y.; Lo, M. F.; Shek,
L.-Y.; Williams, I. D.; Lin, Z.; Jia, G. J. Am. Chem. Soc. 2003, 125, 884.
d) Rickard, C. E. F.; Roper, W. R.; Woodgate, S. D.; Wright, L. J. Angew.
(
Chem., Int. Ed. 2000, 39, 750. (e) Xia, H. P.; He, G. M.; Zhang, H.; Wen,
T. B.; Sung, H. H. Y.; Williams, I. D.; Jia, G. J. Am. Chem. Soc. 2004,
5
e,7d,e
In the course of our synthesis
1
26, 6862.
(
6) (a) Álvarez, E.; Paneque, M.; Poveda, M. L.; Rendón, N. Angew.
Chem., Int. Ed. 2006, 45, 474. (b) Clark, G. R.; Lu, G.-L.; Roper, W. R.;
Wright, L. J. Organometallics 2007, 26, 2167. (c) Paneque, M.; Posadas,
C. M.; Poveda, M. L.; Rendón, N.; Santos, L. L.; Álvarez, E.; Salazar, V.;
Mereiter, K.; Oñate, E. Organometallics 2007, 26, 3403. (d) Clark, G. R.;
Johns, P. M.; Roper, W. R.; Wright, L. J. Organometallics 2006, 25, 1771.
(
5e
(
e) Paneque, M.; Poveda, M. L.; Rendón, N.; Álvarez, E.; Carmona, E.
Chem. Eur. J. 2007, 18, 2711. (f) Bleeke, J. R.; Blanchard, J. M. B.; Donnay,
E. Organometallics 2001, 20, 324. (g) Paneque, M.; Posadas, C. M.; Poveda,
M. L.; Rendón, N.; Salazar, V.; Õnate, E.; Mereiter, K. J. Am. Chem. Soc.
2
003, 125, 9898. (h) Landorf, C. W.; Jacob, V.; Weakley, T. J. R.; Haley,
M. M. Organometallics 2004, 23, 1174. (i) Bleeke, J. R.; Behm, R. J. Am.
Chem. Soc. 1997, 119, 8503. (j) Bleeke, J. R.; Hinkle, P. V. J. Am. Chem.
Soc. 1999, 121, 595. (k) Bleeke, J. R.; Hinkle, P. V.; Rath, N. P.
Organometallics 2001, 20, 1939. (l) Bleeke, J. R.; Hinkle, P. V.; Shokeen,
M.; Rath, N. P. Organometallics 2004, 23, 4139.
11
3
(
7) (a) Liu, S. H.; Ng, W. S.; Chu, H. S.; Wen, T. B.; Xia, H.; Zhou,
Z. Y.; Lau, C. P.; Jia, G. Angew. Chem., Int. Ed. 2002, 41, 1589. (b) Jacob,
V.; Weakley, T. J. R.; Haley, M. M. Angew. Chem., Int. Ed. 2002, 41,
3
470. (c) Effertz, U.; Englert, U.; Podewils, F.; Salzer, A.; Wagner, T.;
Kaupp, M. Organometallics 2003, 22, 264. (d) Zhang, H.; Xia, H. P.; He,
G. M.; Wen, T. B.; Gong, L.; Jia, G. Angew. Chem., Int. Ed. 2006, 45,
2
920. (e) Zhang, H.; Feng, L.; Gong, L.; Wu, L. Q.; He, G. M.; Wen, T. B.;
Yang, F. Z.; Xia, H. P. Organometallics 2007, 26, 2705.
8) Some recent reviews on metallabenzenes: (a) Bleeke, J. R. Chem.
(9) Yand, J.; Jones, W. M.; Dixon, J. K.; Allison, N. T. J. Am. Chem.
Soc. 1995, 117, 9776.
(
ReV. 2001, 101, 1205. (b) Landorf, C. W.; Haley, M. M. Angew. Chem.,
Int. Ed. 2006, 45, 3914. (c) Jia, G. Acc. Chem. Res. 2004, 37, 479. (d)
Bleeke, J. R. Acc. Chem. Res. 2007, 40, 1035. (e) Wright, L. J. Dalton
Trans. 2006, 1821.
(10) (a) Ferede, R.; Hinton, J. F.; Korfmacher, W. A.; Freeman, J. P.;
Allison, N. T. Organometallics 1985, 4, 614. (b) Ferede, R.; Allison, N. T.
Organometallics 1983, 2, 463. (c) Yang, J.; Yin, J.; Abboud, K. A.; Jones,
W. M. Organometallics 1994, 13, 971.
1
0.1021/om7012265 CCC: $40.75  2008 American Chemical Society
Publication on Web 01/16/2008

3
10 Organometallics, Vol. 27, No. 3, 2008
Communications
Scheme 2. Possible Mechanism for the Conversion of 2 to 3
Figure 1. Molecular structure for the complex 3 (50% probability).
Some of the hydrogen atoms are omitted for clarity. Selected bond
distances (Å) and angles (deg): Os(1)-C(1) ) 1.988(7), Os(1)-C(5)
)
2.143(7), Os(1)-C(4) ) 2.160(7), O(1)-C(3) ) 1.239(10),
C(1)-C(2) ) 1.369(11), C(2)-C(3) ) 1.482(12), C(3)-C(4) )
.465(11), C(4)-C(5) ) 1.435(12); C(1)-Os(1)-C(5) ) 90.7(3),
C(1)-Os(1)-C(4) ) 79.0(3), C(4)-Os(1)-C(5) ) 39.0(3),
C(1)-C(2)-C(3) ) 114.8(7), C(2)-C(3)-C(4) ) 113.2(7),
C(3)-C(4)-C(5) ) 114.3(7), O(1)-C(3)-C(4) ) 122.5(8),
O(1)-C(3)-C(2) ) 124.3(8).
solution to the interesting p-osmaphenol 5. A plausible mech-
anism for the formation of 5 is proposed in Scheme 3, which
may involve an electronic tautomerization of 4 to give inter-
mediate D and subsequent intermolecular deprotonation at the
R-carbon. After a slow but mild process, p-osmaphenol 5 can
be produced in high yield.
1
The structure of 5 has also been established by X-ray
three-membered ring made up of C(4), C(5), and Os(1) is 104.8°.
The geometry of the Os center can be viewed as a distorted
octahedron with two PPh3 ligands at the axial positions. The
two chlorides, the vinyl carbon (C(1)), and the olefin double
bond (C(4)dC(5)) are located at the equatorial coordination
sites. The C(3)-O(1) distance of 1.233(4) Å is typical of a
normal carbon-oxygen double bond, which is very close to
1
4
diffraction as depicted in Figure 3. Complex 5 is a typical
metallabenzene derivant. It contains a perfectly coplanar six-
membered ring, which is reflected by the small mean rms
deviation (0.023 Å) from the least-squares plane through the
seven atoms C(1), C(2), C(3), C(4), C(5), O(1), and Os(1). The
carbon-carbon distances in the central ring are approximately
equivalent to each other. This structural feature indicates that
the metallacycle has a delocalized π-electron system. A hydroxyl
group para to the osmium atom can be established by the C-O
bond length of 1.353(7) Å, which is close to those reported for
1
2
that in the analogous complex ((1,2,5-η)-2,4-dimethylpenta-
6i
1
,3-dien-5-oyl)Ir(PMe3)3 (1.235(8) Å) reported by Bleeke. The
bond distance between C(4) and C(5) is 1.435 Å, which is longer
than typical CdC double bonds (∼1.35 Å) and shorter than
typical C-C single bonds (∼1.55 Å), consistent with the value
of a coordinated olefin.
A possible mechanism for the conversion of 2 to 3 under
acidic conditions is shown in Scheme 2. The isomerization
process may be initiated by protonation of the coordinated
terminal alkyne to give intermediate A, which undergoes ꢀ-H
elimination to give B. Keto–enol tautomerization of B to C
followed by dissociation of the protic hydride ligand and
subsequent coordination of the terminal double bond to the metal
center produces 3.
6i
the o-iridaphenol (1.331(20) Å) and the o-osmaphenol (1.370(10)
5
a
13
Å). The C NMR signal at 171.2 ppm (attributed to COH)
also supports the existence of a carbon-oxygen single bond.
1
5
(
In organic phenol, the signal can be observed at 155 ppm;
the downfield chemical shift of 5 is due to the phosphonium
3
1
group on C(2) and the metal center.) The room-temperature
P
1
NMR and H NMR spectra are also consistent with X-ray
diffraction. In the P NMR (in CDCl3) spectrum, a signal
attributed to the phosphonium group on the ring was observed
3
1
4
at 21.2 ppm (dt, J(PP) ) 31.6, 2.4 Hz), while two sets of signals
2
attributed to OsPMe3 were found at -41.1 ppm (dd, J(PP) )
Treatment of 3 with excess PMe3 in dichloromethane afforded
complex 4 in 92% isolated yield. The structure of 4 has also
4
2
2
7.9 Hz, J(PP) ) 2.4 Hz) and -47.2 ppm (dt, J(PP) ) 27.9
4
13
Hz, J(PP) ) 31.6 Hz). Especially, the coupling constants of
been confirmed by X-ray diffraction (Figure 2). In comparison
with 3, complex 4 has a similar structure, except the PPh3 and
one of the chloride ligands were substituted by PMe3 ligands
to give the cationic structure.
2 4
the latter ( J(PP) < J(PP)) indicate that there is a stronger
interaction between the phosphonium group and the trimeth-
Although compound 4 is more stable than 2 and can be
crystallized from solution, it slowly isomerizes in chloroform
(13) Crystallographic data for 4: Mo KR (λ ) 0.710 73 Å) radiation at
1
00(2) K, monoclinic, space group P21/n, a ) 19.161(2) Å, b ) 9.914(1)
Å, c ) 26.300(2) Å, R ) 90°, ꢀ ) 105.754(1)°, γ ) 90°, V ) 4808.2(7)
3
Å , Z ) 4, 9400 reflections measured, 7073 unique reflections (Rint )
(
11) Crystallographic data for 3: Mo KR (λ ) 0.710 73 Å) radiation at
0.0472), which were used in all calculations, R1 (I > 2σ(I)) ) 0.0298,
wR2 (all data) ) 0.0527. CCDC-635740 contains the supplementary
crystallographic data for this complex.
2
23(2) K, monoclinic, space group P21, a ) 11.438(2) Å, b ) 20.166(4)
3
Å, c ) 14.170(3) Å, R ) 90°, ꢀ ) 113.80°, γ ) 90°, V ) 2990.4(11) Å ,
Z ) 2, 10 333 reflections measured, 9867 unique reflections (Rint ) 0.0354),
which were used in all calculations, R1 (I > 2σ(I)) ) 0.0479, wR2 (all
data) ) 0.1238. CCDC-635739 contains the supplementary crystallographic
data for this complex.
(14) Crystallographic data for 5: Mo KR (λ ) 0.710 73 Å) radiation at
100(2) K, orthorhombic, space group Pbca, a ) 16.122(2) Å, b ) 17.089(2)
3
Å, c ) 32.257(4) Å, R ) 90°, ꢀ ) 90°, γ ) 90°, V ) 8887.3(18) Å , Z )
8, 7734 reflections measured, 5399 unique reflections (Rint ) 0.0923), which
were used in all calculations, R1 (I > 2σ(I)) ) 0.0424, wR2 (all data) )
0.0816. CCDC-635741 contains the supplementary crystallographic data
for this complex.
(12) Other complexes analogous to 3: (a) Hughes, R. P.; Trujillo, H. A.;
Egan, J. W., Jr.; Rheingold, A. L. J. Am. Chem. Soc. 2000, 122, 2261. (b)
Hughes, R. P.; Trujillo, H. A.; Egan, J. W., Jr.; Rheingold, A. L.
Organometallics 1999, 18, 2766. (c) Hughes, R. P.; Trujillo, H. A.; Gauri,
A. J. Organometallics 1995, 14, 4319.
(15) Dean, J. A., Lange’s Handbook of Chemistry, McGraw-Hill: New
York, 1998; Chapter 7.97.

Communications
Organometallics, Vol. 27, No. 3, 2008 311
Figure 2. Molecular structure for the complex cation of 4 (50%
probability). Some of the hydrogen atoms are omitted for clarity.
Selected bond distances (Å) and angles (deg): Os(1)-C(1) )
Figure 3. Molecular structure for the complex cation of 5 (50%
probability). Some of the hydrogen atoms are omitted for clarity.
Selected bond distances (Å) and angles (deg): Os(1)-C(1) )
2
.019(4), Os(1)-C(5) ) 2.143(3), Os(1)-C(4) ) 2.153(3),
O(1)-C(3) ) 1.233(4), C(1)-C(2) ) 1.376(5), C(2)-C(3) )
.460(5), C(3)-C(4) ) 1.497(5), C(4)-C(5) ) 1.421(5); C(1)-Os-
1)-C(5) ) 87.1(2), C(1)-Os(1)-C(4) ) 78.1(1), C(4)-Os(1)-C(5)
38.6 (1), C(1)-C(2)-C(3) ) 114.0(3), C(2)-C(3)-C(4) )
2
.032(5), Os(1)-C(5) ) 1.918(6), O(1)-C(3) ) 1.349(6), C(1)-C(2)
1.388(8), C(2)-C(3) ) 1.443(7), C(3)-C(4) ) 1.377(8),
C(4)-C(5) ) 1.385(8); C(1)-Os(1)-C(5) ) 87.3(2), Os(1)-C-
1)-C(2) ) 130.0(4), C(1)-C(2)-C(3) ) 121.9(5), C(2)-C(3)-C(4)
123.5(5), C(3)-C(4)-C(5) ) 124.6(5), C(4)-C(5)-Os(1) )
32.4(4).
)
1
(
(
)
1
)
1
12.8(3), C(3)-C(4)-C(5) ) 115.9(3), O(1)-C(3)-C(4) ) 123.5(3),
O(1)-C(3)-C(2) ) 123.7(4).
Scheme 3. Proposed Mechanism for the Isomerization
of 4 to 5
well-characterized p-osmaphenol. We have succeeded in prepar-
ing it under mild conditions via a comparatively convenient
method. In comparison with the previously reported o-iradaphe-
nol and o-osmaphenol, it is an extension of a metallaphenol
with a different location of the hydroxyl group, on the carbon
para to the metal atom. In addition, its stability should permit
further study on the chemical and physical properties. Detailed
mechanisms of these reactions and other chemical reactions or
transformations as well as the optical and electrical properties
of these interesting complexes are under investigation.
Acknowledgment. This work was financially supported
by the program for New Century Excellent Talents in
University of China (No. NCET-04-0603), the National
Science Foundation of China (Nos. 20572089 and 20772100),
the Young Talent Project of the Department of Science &
Technology of Fujian Province (No. 2007F3095), and the
Program for New Century Excellent Talents in Fujian
Province University.
ylphosphine group which is opposite to the phosphonium group
on the ring. In the H NMR (in CDCl3) spectrum, the four
hydrogen signals on the central ring appeared at 16.5 (dd,
OsCHCH), 13.3 (d, OsCHC(PPh3)), 12.2 (s, COH), and 8.4 ppm
1
(
dd, OsCHCH), respectively, consistent with the effect of the
delocalized π-electronic system. The chemical shift of the proton
opposite to the phosphonium group is significantly downfield
compared with that at the ortho position, which also shows the
effect of the delocalized π-electronic system.
Supporting Information Available: Text giving experimental
details, characterization data, and NMR spectra for all isolated
compounds and CIF files giving X-ray data for 3-5. This material
is available free of charge via the Internet at http://pubs.acs.org.
In comparison with many other metallabenzenes and organic
phenols, 5 is an air-stable complex (both in the solid state and
in solution). The solution remains almost unchanged under air
for over 1 week. To the best of our knowledge, 5 is the first
OM7012265