Synthesis and reactivity of new (methoxy)methyl complexes of manganese(I) and rhenium(I)

Article abstract of DOI:10.1021/om060459n

The reactions of Na[M(CO)₃(bipy)] (M = Mn, Re) with ClCH ₂OCH₃ afford the (methoxy)methyl complexes [M(CH ₂-OCH₃)(CO)₃(bipy)] (M = Mn, 1; Re, 2), characterized by IR and NMR spectroscopy and, in the case of I, also by X-ray diffraction. Highly electrophilic species, presumably cationic alkylideneoxonium complexes, although they were not detected, were prepared in situ by reaction of I and 2 with methyl inflate. These species react with neutral nucleophiles such as SMePh to generate the alkylidenesulfonium complexes [M(CH ₂SPhMe)-(CO)₃(bipy)]⁺[OTf]^- (M = Mn, 3; Re, 4) and with styrene to give phenylcyclopropane and the corresponding inflate complexes [M(OTf)(CO)₃(bipy)].

Full text of DOI:10.1021/om060459n

Organometallics 2006, 25, 4909-4912
4909
Notes
Synthesis and Reactivity of New (Methoxy)methyl Complexes of
Manganese(I) and Rhenium(I)
,†
‡
,†
†
Eva Hevia,* Daniel Miguel, Julio P e´ rez,* and V ´ı ctor Riera
Departamento de Qu ´ı mica Org a´ nica e Inorg a´ nica-IUQOEM, Facultad de Qu ´ı mica, UniVersidad de
OViedo-CSIC, OViedo 33006, Spain, and Departamento de Qu ´ı mica Inorg a´ nica, Facultad de Ciencias,
UniVersidad de Valladolid, Valladolid 47071, Spain
ReceiVed May 25, 2006
Summary: The reactions of Na[M(CO)3(bipy)] (M ) Mn, Re)
with ClCH2OCH3 afford the (methoxy)methyl complexes [M(CH2-
OCH3)(CO)3(bipy)] (M ) Mn, 1; Re, 2), characterized by IR
and NMR spectroscopy and, in the case of 1, also by X-ray
diffraction. Highly electrophilic species, presumably cationic
alkylideneoxonium complexes, although they were not detected,
were prepared in situ by reaction of 1 and 2 with methyl triflate.
These species react with neutral nucleophiles such as SMePh
to generate the alkylidenesulfonium complexes [M(CH2SPhMe)-
[M(CH2OCH3)(CO)3(bipy)] (M) Mn, Re), their reactivity
toward electrophiles, and their ability to cyclopropanate styrene
in the presence of an electrophile. The organometallic fragments
{M(CO) (bipy)} (M ) Mn, Re) have been widely studied in
3
coordination and organometallic chemistry and, in the particular
4
5
case of M ) Re, in the fields of photophysics, CO2 activation,
6
and biological labeling; however their use as auxiliaries for
7
organic transformations remains less explored.
+
-
(
CO)3(bipy)] [OTf] (M ) Mn, 3; Re, 4) and with styrene to
Results and Discussion
giVe phenylcyclopropane and the corresponding triflate com-
plexes [M(OTf)(CO)3(bipy)].
A THF solution of Na[MnCO)3(bipy)] (generated in situ by
reaction of the bromo complex [MnBrCO)3(bipy)] and sodium
amalgam, see Experimental Section) was allowed to react with
chloromethyl methyl ether, yielding the new compound
Introduction
Although much less studied than heteroatom-stabilized
Fischer carbenes, highly electrophilic, low oxidation state non-
stabilized carbenes have been found to mediate several important
[Mn(CH2OCH3)(CO)3(bipy)] (1) (Scheme 1). The reaction was
accompanied by a dramatic color change from deep blue-violet
to red. The νCO IR bands of the crude solution of 1 showed the
characteristic pattern for a fac-tricarbonyl moiety, with two
1
organic transformations, such as olefin cyclopropanation. One
of the synthetic approaches to the nonstabilized carbenes is the
-
1
intense bands at 1991 and 1889 (broad) cm . These values
are significantly shifted to lower frequencies with respect to
reaction of an electrophile with R-substituted alkyl complexes
2
LnM-CH2X (where X ) OR, SR, halide, etc.) (eq 1).
-1
the bromo precursor (2022, 1934, 1914 cm ), but they are only
slightly different from the values found for the (methylthio)-
-1
methyl complex [Mn(CH2SCH3)(CO)3(bipy)] (1996, 1896 cm ).
The higher electron-releasing ability of the (methoxy)methyl
ligand [compared to the (methylthio)methyl group] accounts for
-
1
the difference of 5 cm in the values of the νCO IR of these
compounds. Compound 1 was isolated as red crystals in a high
yield and characterized in solution using NMR spectroscopy
Recently we reported the synthesis and characterization of
new (alkylthio)methyl complexes [M(CH2SR)(CO)3(bipy)]
3
(
M ) Mn, Re), which react with methyl triflate to afford stable
1
and in the solid state by X-ray diffraction studies. Its H NMR
cationic alkylidenesulfonium complexes [M(CH2SRMe)-
spectrum showed the presence of four multiplets for the
+
-
(
CO)3(bipy)] [OTf] . The latter do not react with styrene at
room temperature; however they cyclopropanate this olefin at
10 °C. In general, (alkoxy)methyl complexes can react with
(4) See for instance: (a) Lees, A. J. Chem. ReV. 1987, 87, 711. (b) Meyer,
T. J. Acc. Chem. Res. 1989, 22, 163. (c) Schanze, K. S.; MacQueen, D. B.;
Perkins, T. A.; Caban, L. A. Coord. Chem. ReV. 1993, 122, 63. (d) Stufkens,
D. J.; Vlcek, A., Jr. Coord. Chem. ReV. 1998, 177, 127. (e) Farrell, I. R.;
Vlcek, Jr., A. Coord. Chem. ReV. 2000, 208, 87.
1
strong electrophiles to form highly electrophilic alkylidene-
oxonium species, which cannot be detected but can cyclo-
propanate olefins in much milder conditions than related
alkylidenesulfonium complexes. Herein we report the synthesis
and characterization of the new (methoxy)methyl complexes
(5) See for instance: (a) Farrel I. R.; Vlcek, A., Jr. Coord. Chem. ReV.
2
2
2
000, 208, 87. (b) Striplin, D. R.; Crosby, G. A. Coord. Chem. ReV. 2001,
11, 163. (c) Hightower, S. E.; Corcoran, R. C.; Sullivan, B. P. Inorg. Chem.
005, 44, 9601. (d) Belliston-Bittner, W.; Dunn, A. R.; Nguyen, Y. H. L.;
Stuehr, D. J.; Winkler, J. R.; Gray, H. B. J. Am. Chem. Soc. 2005, 127,
15907. (e) Reece, S. Y.; Nocera, D. G. J. Am. Chem. Soc. 2005, 127, 9448.
(6) See for instance: (a) Kutal, C.; Corbin, J.; Ferraudi, G. Organo-
metallics 1987, 6, 553. (b) Scheiring, T.; Klein, A.; Kaim, W. J. Chem.
Soc., Perkin Trans. 2 1997, 2569.
(7) For recent examples of our own work in this area see: (a) Hevia, E.;
P e´ rez, J.; Riera, V.; Miguel, D. Angew. Chem., Int. Ed. 2002, 20, 3558. (b)
Hevia, E.; P e´ rez, J.; Riera, V.; Miguel, D.; Campomanes, P.; Men e´ ndez,
M. I.; Sordo, T. L.; Garc ´ı a-Granda, S. J. Am. Chem. Soc. 2003, 125, 3706.
*
To whom correspondence should be addressed. Fax: 34 98510 3446.
Tel: 34 98510 3465. E-mail: japm@uniovi.es.
†
Universidad de Oviedo-CSIC.
Universidad de Valladolid.
‡
(1) Brookhart, M.; Studabaker, W. B. Chem. ReV. 1987, 87, 411.
(2) Jolly, P. W.; Pettit, R. J. Am. Chem. Soc. 1955, 88, 5044.
(3) Hevia, E.; P e´ rez, J.; Riera, V.; Miguel, D. Organometallics 2002,
2
1, 5312.
1
0.1021/om060459n CCC: $33.50 © 2006 American Chemical Society
Publication on Web 08/22/2006

4
910 Organometallics, Vol. 25, No. 20, 2006
Notes
Scheme 1
bipyridine ligand, consistent with the presence of a mirror plane
in the molecule. In addition, two resonances at 3.68 and 2.99
ppm were found for the methylene and methyl groups of the
(
methoxy)methyl ligand, respectively. These groups give rise
13
to two signals in the C NMR spectrum at 91.28 and 65.29,
respectively. These values are considerably further downfield
than the ones found for the related (alkylthio)methyl complex
Figure 1. Molecular structure of 1 with 30% probability displace-
ment ellipsoids.
1
[
1.27 (CH2) and 1.82 (CH3) ppm in the H NMR spectrum,
3
3
2.36 (CH2) and 24.29 (CH3) ppm in the 13C NMR spectrum],
showing the remarkable influence of the heteroatom present in
the R-position to the CH2 moiety. Following the same procedure,
the rhenium congener [Re(CH2OCH3)(CO)3(bipy)] (2) was
prepared and spectroscopically characterized (see Experimental
Section).
Table 1. Selected Bond Distances and Angles for 1
Mn(1)-C(4)
Mn(1)-C(1)
Mn(1)-C(2)
Mn(1)-C(3)
2.136(3)
1.835(3)
1.790(3)
1.785(3)
Mn(1)-N(1)
Mn(1)-N(2)
C(4)-O(4)
O(4)-C(5)
2.042(2)
2.047(2)
1.387(3)
1.413(3)
The chemical shifts of the resonances of the CH3 moiety in
C(1)-Mn(1)-C(4)
C(2)-Mn(1)-C(4)
C(3)-Mn(1)-C(4)
N(1)-Mn(1)-C(4)
N(2)-Mn(1)-C(4)
C(3)-Mn(1)-C(1)
C(3)-Mn(1)-C(2)
C(2)-Mn(1)-C(1)
C(3)-Mn(1)-N(1)
178.28(10)
88.69(10)
86.91(11)
84.15(9)
C(2)-Mn(1)-N(1)
C(1)-Mn(1)-N(1)
C(3)-Mn(1)-N(2)
C(2)-Mn(1)-N(2)
C(1)-Mn(1)-N(2)
N(1)-Mn(1)-N(2)
O(4)-C(4)-Mn(1)
C(4)-O(4)-C(5)
170.70(10)
97.03(10)
172.07(10)
95.41(10)
94.85(10)
78.29(8)
1
13
complex 2 in the H and C NMR spectra (2.83 and 63.89
ppm, respectively) show little variation from the corresponding
ones for complex 1 (2.99 and 65.29 ppm), whereas for the
methylene group (which is directly bonded to the metal and, in
consequence, will be more affected by the change of the
transition metal from Mn to Re) there is a significant deviation
in the chemical shifts (3.04 and 81.70 ppm for 2 versus 3.68
and 91.28 ppm for 1 in the 1H and C NMR spectra,
respectively).
86.62(9)
91.70(12)
89.03(12)
90.27(12)
96.48(10)
113.93(3)
113.1(2)
13
In a first attempt to prepare cationic oxonium or methylene
complexes following the methodology previously employed for
the iron compounds [(CO)2CpFe(CH2XR)], compounds 1 and
The structure of 1 was characterized by X-ray diffraction
studies (Figure 1 and Table 1). Despite the fact that (methoxy)-
methyl complexes are well-known and important intermediates
in synthesis, the number of elucidated crystal structures is still
relatively scarce. On searching the Cambridge Structural
1
2
were treated with a stoichiometric amount of triflic acid in
CH2Cl2. The triflate compounds [M(OTf)(CO)3(bipy)] were
formed instantaneously, as shown by the IR νCO bands of the
solutions, which shifted almost 30 cm in each case to higher
frequencies. When these reactions were carried out in a NMR
-1
8
Database, only 13 complexes were found, and just one of these
9
contains manganese. The molecular structure of 1 shows a
1
tube in CD2Cl2 solution, the H NMR spectra revealed not only
manganese atom in a distorted octahedral environment coordi-
the signals of the triflate complexes but also a singlet at 3.25
ppm assignable to Me2O, showing that the metal-alkyl bond,
and not the oxygen atom, has been the site of electrophilic attack.
This is an interesting result, as previous examples found in the
literature show that for other related complexes, such as [Cp(Ph2-
nated to three carbonyl ligands in a fac disposition, a chelating
1
bipyridine, and a η (C) (methoxy)methyl ligand. The major
deviation from an idealized octahedral geometry is imposed by
the bite angle of the rigid bidentate ligand bipyridine [N1MnN2:
7
8.29(8)°]. The Mn-CO distance is significantly longer for
the carbonyl ligand trans to the methoxy(methyl) ligand [1.835
3) Å versus 1.790(3) and 1.785(3) Å for the other two Mn-
11
12
PCH2CH2PPh2)Fe(CH2OCH3)] or [(CO)5W{CH(OMe)OPh}],
1
the protonation occurs at the oxygen atom. This difference can,
in part, be due to the high reactivity that the metal-carbon bonds
in these manganese and rhenium compounds present toward
acids. For instance, they react with much weaker acids than
HOTf such as phenols or thiols.
(
CO distances], which indicates that the alkyl ligand has a
stronger trans influence than the nitrogens of the bipy ligand.
The large trans influence of the CH2OCH3 ligand has been
previously reported.10 The Mn-C distance [2.136(3) Å] is
within the range for a single Mn-C bond found in other alkyl
complexes of manganese tricarbonyl fragments such as the
related (alkylthio)methyl [Mn(CH2SPh)(CO)3(bipy)] [2.125(4)
We next studied the reactivity of 1 and 2 toward the strong
methylating agent MeOTf. The H NMR spectra of the solutions
1
in CD2Cl2 showed once again the formation of the triflate
compounds and Me2O. This result implies that this time the
electrophilic attack has occurred on the oxygen atom, facilitating
the O-C bond cleavage. No (methyl)ethyl ether (the expected
product of an electrophilic attack to the M-C bond) was
3
Å] or the (methoxy)methyl [Mn(CH2OCH3)(CO)3(dppp)] (dppp
9
)
1,3-bis(diphenylphosphino)propane) [2.173(10) Å].
(8) Allen F. H. Acta Crystallogr. Sect. B 2002, 58, 380.
(
9) Mandal, S. K.; Krause, J. A.; Orchin, M. J. Organomet. Chem. 1994,
4
67, 113.
(11) Brookhart, M., Tucker, J. R.; Flood, T. C.; Jensen, J. J. Am. Chem.
(
10) (a) Polson, S. M.; Hansen, L.; Marzilli, L. G. Inorg. Chem. 1997,
Soc. 1980, 102, 1203.
(12) Casey, P. C.; Polichnowski, S. W. J. Am. Chem. Soc. 1977, 99,
3
6, 307. (b) Cini, R.; Moore, S. J., Marzilli, L. G. Inorg. Chem. 1998, 37,
6
890.
6097.

Notes
Organometallics, Vol. 25, No. 20, 2006 4911
Scheme 2
Table 2. Crystal Data and Refinement Details for 1
formula
fw (g‚mol-1)
cryst syst
space group
a (Å)
C15H13mnN2O4
340.21
triclinic
P1h
6.9674(7)
8.5023(8)
14.1923(13)
74.046(2)
81.882(2)
69.172(2)
3372.5(6)
2
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
3
V (Å )
Z
F(000)
348
1.497
Dc (g‚cm-3)
cryst size (mm)
µ (Mo KR, mm-1)
temperature (K)
λ(Mo KR) (Å)
scan range (deg)
no. of data/restraints/params
R1/wR2 (I > 2σ(I))
R1/wR2 (all data)
0.12 × 0.19 × 0.29
Scheme 3
0.893
298(2)
0.71073
1.49 e θ e 23.28
2149/0/200
0.034/0.0962
0.0359/0.0977
detected. The fact that the only organometallic products observed
in the H NMR spectra are the triflate compounds can be due
1
noteworthy that the treatment of the triflate complexes with
sodium amalgam affords the Na[M(CO)3(bipy)] salts, recycling
the metal fragments. The triflate complexes are obtained in
almost quantitative yields; however, the conversion of styrene
to phenylcyclopropane is only about 45-50%. This can be
explained by considering that the transient carbenoid species
to the instability, at least at room temperature, of the alkylidene-
oxonium compounds, which preclude their observation by NMR
techniques.
However, when the same methodology was employed in
the presence of 1 molar equiv of thioanisole, the alkylidene-
15
+
-
sulfonium species [M(CH2SPhMe)(CO)3(bipy)] [OTf] (M )
Mn, 3; Re, 4) were obtained (Scheme 2). This can be
16
can evolve through different pathways. A variety of side
3
reactions related to decomposition of intermediate carbene
species are known, and generally an excess of the organometallic
rationalized in terms of the initial formation of highly electro-
philic alkylideneoxonium complexes that then would react with
a weak nucleophile such as PhSMe to afford the more stable
alkylidenesulfonium complexes 3 and 4 along with dimethyl
ether. This result is particularly noteworthy since it contrasts
with the ones previously found for the complexes 3 and 4, which
were found to be inert toward neutral nucleophiles such as
pyridine, dimethyl sulfide, or PPh3, and illustrates the higher
electrophilic character of the alkylideneoxonium complexes. On
the other hand, Barefield has shown that the reactions of
1
complex is employed. One possible decomposition route would
be the coupling of two CH2 moieties to form ethylene and an
unsaturated organometallic fragment, which would be trapped
by the triflate anion. The cyclopropane conversions are thus
similar to the ones obtained using alkylidenesulfonium com-
plexes [M(CH2SPhMe)(CO)3(bipy)] [OTf] (M ) Mn, 3; Re,
); however for the latter temperatures above 100 °C were
required, whereas employing complexes 1 and 2 as precursors,
the in situ-generated alkylideneoxonium complexes successfully
cyclopropanate styrene under much milder conditions.
+
-
3
3
4
[
Cp(CO)2Fe(CH2SPh2)]BF4 with nucleophiles occur in two
steps. First the cation [Cp(CO)2Fe(CH2SPh2)] undergoes
reversible dissociative loss of SPh2 to afford the relevant
+
Experimental Section
+
methylene complex [Cp(CO)2Fe(dCH2)] followed by the
General procedures were given elsewhere.17
capture of this reactive species with the relevant nucleo-
phile.13 If a similar two-step mechanism was involved in the
reactions of these rhenium and manganese alkylidenoxonium
and alkylidenesulfonium compounds with nucleophiles, then
their different reactivity toward neutral nucleophiles could be
explained in terms of the diference in the relative rates of the
two steps.
We investigated the ability of 1 and 2 to function as
cyclopropanation reagents by studying their reaction with
methyl triflate in the presence of styrene.14 The mixture of the
reagents was carried out at low temperature (-78 °C) in order
to minimize possible side reactions or partial degradation of
the reactive cationic intermediates, in deuterated dichloro-
methane, and monitored by 1H NMR spectroscopy. After
allowing the samples to reach room temperature, the spectra
showed the conversion of the (methoxy)methyl compounds 1
and 2 to the triflate complexes [M(OTf)(CO)3(bipy)] (M ) Mn,
Re), as well as a mixture of phenylcyclopropane, unreacted
styrene, and dimethyl ether (Scheme 3). At this point it is
Crystal Structure Determination for Compound 1. A suitable
crystal was attached to a glass fiber and transferred to a Bruker
AXS SMART 1000 diffractometer with graphite-monochromatized
Mo KR X-radiation and a CCD area detector. A hemisphere of the
reciprocal space was collected up to 2θ ) 48.6°. Raw frame data
were integrated with the SAINT program.18 The structure was
solved by direct methods with SHELXTL.19 A semiempirical
2
0
absorption correction was applied with the program SADABS.
1
(
15) The yields of phenylcyclopropane have been evaluated by H NMR
integration using ferrocene as an internal standard, and they have been found
to be 42((5)% with compound 1 and 47%((5)% with compound 2. Similar
yields of phenylcyclopropane were observed when the experiment was
repeated with increasing amounts of styrene.
(
16) However, no spectroscopic evidence of the relevant methylene
complex was found even when the reaction was carried out at low
1
temperature and monitored by H NMR.
(
17) Hevia E.; P e´ rez, J.; Riera, V.; Miguel, D. Organometallics 2002,
1, 1966.
(18) SAINT+, SAX area detector integration program, Version 6.02;
Bruker AXS, Inc.: Madison, WI, 1999.
2
(
19) Sheldrick, G. M. SHELXTL, An integrated system for solving,
refining, and displaying crystal structures from diffraction data, Version
5.1; Bruker AXS, Inc.: Madison, WI, 1998.
(20) Sheldrick, G. M. SADABS, Empirical Absorption Correction Pro-
gram; University of G o¨ ttingen: G o¨ ttingen, Germany, 1997.
(
(
13) McCarten, P.; Barefield, E. K. Organometallics 1998, 17, 4645.
14) See for instance: O’Connor, E. J.; Brandt, S.; Helquist, P. J. Am.
Chem. Soc. 1987, 109, 3739.

4912 Organometallics, Vol. 25, No. 20, 2006
Notes
All non-hydrogen atoms were refined anisotropically. Hydrogen
atoms were set in calculated positions and refined as riding atoms
with a common thermal parameter. All calculations and graphics
were made with SHELXTL. Crystal and refinement data are
presented in Table 2.
decomposition due to traces of oxygen. The resulting dark blue-
violet solution was transferred via cannula onto another flask
containing a solution of ClCH OCH (45 µL, 0.52 mmol) in THF
2
3
(10 mL) previously cooled at -78 °C. The color of the solution
changed to orange. Similar workup as described for 1 affords
compound 2 as an orange microcrystalline solid. Yield: 0.20 g,
2 3 3
Synthesis of [Mn(CH OCH )(CO) (bipy)] (1). To an orange
-1
1
solution of [MnBr(CO) (bipy)] (0.30 g, 0.80 mmol) in THF (30
3
2 2
77%. IR (THF, cm ): 1994, 1885. H NMR (CD Cl ): 9.05, 8.19,
mL) was added 15.00 g of 0.5% sodium amalgam, and the mixture
was vigorously stirred for 2 h. Although a deep purple color
developed after 15 min, IR monitoring showed that longer reaction
times are required to convert all the starting material into an anionic
species, for which IR νCO bands appear at 1912, 1823, and 1782
2 3
7.99, 7.46 (m, 2H each, bipy), 3.04 (s, 2H, CH ), 2.83 (s, 3H, CH ).
13
1
C{ H} NMR (CD Cl ): 203.81 (2CO), 193.96 (CO), 155.41,
2
2
153.10, 137.83, 126.56, 123.10 (bipy), 81.70 (CH ), 63.89 (CH ).
2
3
Anal. Calcd for C H N O Re: C, 38.21; H, 2.77; N, 5.94. Found:
15
13
2
4
C, 38.32; H, 2.71; N, 5.85.
-
1
cm . The reaction mixture was allowed to settle, and the solution
was transferred onto a solution of ClCH OCH (60 µL, 0.80 mmol)
2 3 3
Cyclopropanation of Styrene. [M(CH OCH )(CO) (bipy)] (0.03
mmol) was dissolved in CD Cl (0.5 mL), and a stoichiometric
2 2
2
3
in THF (10 mL) previously cooled at -78 °C using a cannula tipped
with filter paper. The color of the solution changed instantaneously
from deep violet to deep red. The solution was filtered through
Florisil. The solvent was removed under vacuum, affording complex
amount of styrene (3.5 µL, 0.03 mmol) was added. The solution
was cooled at -78 °C, and MeOTf (3.4 µL, 0.03 mmol) was then
introduced. The mixture was allowed to reach room temperature.
1
A H NMR spectrum recorded 4 h later showed the presence of
1
as a red solid. Slow diffusion of hexane at room temperature
[
M(OTf)(CO)
propane [7.22 (m, 5H, Ph), 1.78 (m, 1H), 0.93 (m, 2H), 0.72 (m,
H)].
3 2
(bipy)], Me O, unreacted styrene, and phenylcyclo-
into a solution of 1 in THF afforded red crystals, one of which
was employed for X-ray analysis. Yield: 0.21 g, 77%. IR(THF,
2
-
1
1
cm ): 1991, 1889. H NMR(CD
H each, bipy), 3.68 (s, 2H, CH ), 2.99 (s, 3H, CH
CD Cl ): 228.34 (2CO), 212.97 (CO), 154.24, 152.88, 136.33,
24.95, 122.04 (bipy), 91.28 (CH ), 62.59 (CH ). Anal. Calcd for
: C, 52.95; H, 3.85; N, 8.23. Found: C, 52.87; H,
2 2
Cl ): 9.07, 8.09, 7.87, 7.36 (m,
13
1
2
(
1
2
3
). C{ H} NMR
Acknowledgment. We thank the Ministerio de Ciencia y
2
2
Tecnolog ´ı a (grants BQU2003-08649 and BQU2002-03414) for
supporting this work. E.H. gratefully acknowledges the Min-
isterio de Educaci o´ n y Ciencia for a Ram o´ n y Cajal Fellowship.
2
3
15 2 4
C H13MnN O
3
.77; N, 8.35.
Synthesis of [Re(CH
solution of [ReBr(CO) (bipy)] (0.30 g, 0.59 mmol) in THF (30 mL)
2
3 3
OCH )(CO) (bipy)] (2). To a yellow
3
Supporting Information Available: X-ray crystallographic data
for compound 1 in CIF format. This material is available free of
charge via the Internet at http://pubs.ac.org.
was added 15.00 g of 0.5% sodium amalgam, and the mixture was
allowed to stir at room temperature for 24 h. Given the long reaction
times required, a flask provided with a Young stopcock (rather than
a greased glass stopcock) was employed to minimize partial
OM060459N