Electrophilic additions of metal fragments containing 11- and 12-group elements to the anion carbide cluster [Fe5MoC(CO)17]2-. X-ray crystal structures of (NEt4)[Fe5MoAuC(CO)17(PMe3)] and [Fe5MoAu2C(CO)17(dppm)]

Article abstract of DOI:10.1021/om000976k

The reaction of (NEt₄)₂[Fe₅MoC(CO)₁₇] with cationic metal fragments gives a series of clusters whose most striking structural feature is the selective addition of the incoming metal units on the triangular Fe₂Mo face of the starting anion. The use of Au₂(dppm)²⁺ (dppm = diphenylphosphinomethane) gives the cluster [Fe₅MoAu₂C(CO)₁₇(dppm)] in which the di-gold fragment adopts an unprecedented bonding mode.

Full text of DOI:10.1021/om000976k

Organometallics 2001, 20, 1575-1579
1575
Electr op h ilic Ad d ition s of Meta l F r a gm en ts Con ta in in g
1
1- a n d 12-Gr ou p Elem en ts to th e An ion Ca r bid e Clu ster
2
-
[
F e MoC(CO) ] . X-r a y Cr ysta l Str u ctu r es of
5
17
(
NEt )[F e MoAu C(CO) (P Me )] a n d
4
5
17
3
†
[
F e MoAu C(CO) (d p p m )]
5
2
17
‡
‡
,‡
‡
Roser Reina, Laura Rodr ´ı guez, Oriol Rossell,* Miquel Seco,
§
§
Merc e` Font-Bardia, and Xavier Solans
Departament de Qu ı´ mica Inorg a` nica, Universitat de Barcelona, Mart ı´ i Franqu e` s 1,
E-08028 Barcelona, Spain, and Departament de Cristal‚lografia, Mineralogia i Dip o` sits
Minerals, Universitat de Barcelona, Mart ı´ i Franqu e` s s/ n., E-08028 Barcelona, Spain
Received November 16, 2000
The reaction of (NEt
4 2 5
) [Fe MoC(CO)17] with cationic metal fragments gives a series of
clusters whose most striking structural feature is the selective addition of the incoming
2
+
metal units on the triangular Fe
diphenylphosphinomethane) gives the cluster [Fe
gold fragment adopts an unprecedented bonding mode.
2
Mo face of the starting anion. The use of Au
2
(dppm) (dppm
)
5
MoAu C(CO)17(dppm)] in which the di-
2
In tr od u ction
results with those given by the use of the close anions
2
-
2-
[Fe6C(CO)16] and [Ru5WC(CO)17] .
Although they belong to the same group, iron and
ruthenium show marked differences in their cluster
chemistry. Ruthenium clusters are far more common
than those of iron, given the higher thermodynamic
stability of their species and the ease with which they
crystallize. The difference in thermodynamic stability
between the iron and ruthenium clusters is shown, for
example, in the reaction of the hexanuclear carbide
Resu lts a n d Discu ssion
(
NEt4)2[Fe5MoC(CO)17] reacted with ClAuPPh3 in
tetrahydrofuran to give air-stable red crystals of
NEt4)[Fe5MoAuC(CO)17(PPh3)], (NEt4)[1] (Scheme 1).
Although we were unable to grow single crystals of
them, the cluster (NEt4)[Fe5MoAuC(CO)17(PMe3)], (NEt4)-
2], obtained by the same method, gave suitable crystals
(
2
-
1
2
anions [M6C(CO)16] with (ClAu)2dppm (M ) Fe, Ru ).
Thus, for M ) Fe, the cluster [Fe4Au2C(CO)12(dppm)]
was formed after partial cleavage of the octahedral iron
anion, while the ruthenium anion gave the species [Ru6-
Au2C(CO)16(dppm)] in which the Ru6 octahedron is
unaltered. On the other hand, the ruthenium anion
clusters are much more reactive to electrophilic species,
[
for an X-ray crystal structure determination. The struc-
ture of the anion is shown in Figure 1, together with
the atomic numbering scheme; the most significant bond
distances and angles are given in Table 1. The structure
5
may be regarded as derived from that of [Fe MoC-
2
- 5
(CO) ]
1
7
with one Fe Mo triangular face of the octa-
2
+
2-
+
such as AuPPh3 . For example, while [Fe6C(CO)16]
hedron capped by the AuPMe3 moiety. The carbide is
roughly equidistant from the five iron atoms with Fe-C
distances in the range 1.871(8)-1.954(7) Å, not signifi-
cantly different from those reported for the starting
anion. Fifteen carbonyls are terminal, and two bridge
the Fe(4)-Fe(2) and Mo-Fe(5) edges unsymmetrically.
The products obtained by the reaction between the iron
+
reacts with an excess of AuPPh3 to give the anion
Fe6AuC(CO)16(PPh3)] , the analogous [Ru6C(CO)16]
-
2-
[
can incorporate up to two gold units and give the neutral
compound [Ru6Au2C(CO)16(PMePh2)2].3,4
Here we describe the reaction of the heteronuclear
2
-
anion [Fe5MoC(CO)17] with the electrophilic fragments
2
-
+
+
2+
5 17
cluster [Fe MoC(CO) ] and the ruthenium analogue
MPPh3 (M ) Au, Cu, Ag), AuPMe3 , Au2(diphos)
,
2
-
+
+
[Ru5WC(CO)17] with gold halide complexes are differ-
ent. In the first case, only the mono-gold derivative is
obtained despite the use of an excess of the gold reagent,
HgMo(CO)3Cp , and HgW(CO)3Cp and compare the
†
Dedicated to Prof. Rafael Us o´ n on the occasion of his 75th birthday.
*
To whom correspondence should be addressed. E-mail:
while in the second case the di-gold species [Ru5WAu2C-
oriol.rossell@qi.ub.es.
4
(
CO)17(PEt3)2] is isolated. However, the most intriguing
‡
Departament de Qu ´ı mica Inorg a` nica.
Departament de Cristal‚lografia, Mineralogia i Dip o` sits Minerals.
§
structural feature arises from the fact that the gold
fragment caps an Fe2Mo triangular face of the Fe/Mo
anion; in contrast, an Ru3 face of the Ru/W cluster is
capped. Although the higher Mo-Au bonding energy in
comparison with that of the Fe-Au could be
(1) Rossell, O.; Seco, M.; Segal e´ s, G.; J ohnson, B. F. G.; Dyson, P.
J .; Ingham, S. L. Organometallics 1996, 15, 884.
2) Bailey, P. J .; Beswick, M. A.; Lewis, J .; Raithby, P. R.; Ram ´ı rez
de Arellano, M. C. J . Organomet. Chem. 1993, 459, 293.
3) Rossell, O.; Seco, M.; Segal e´ s, G.; Alvarez, S.; Pellinghelli, M.
A.; Tiripicchio, A.; de Montauzon, D. Organometallics 1997, 16, 236.
4) Bunkhall, S. R.; Holden, H. D.; J ohnson, B. F. G.; Lewis, J .; Pain,
G. N.; Raithby, P. R.; Taylor, M. J . J . Chem. Soc., Chem. Commun.
984, 1726.
(
(
(
(5) Tachikawa, M.; Sievert, A. C.; Muetterties, M. R.; Thompson,
M. R.; Day, S. S.; Day, V. W. J . Am. Chem. Soc. 1980, 102, 1726.
1
1
0.1021/om000976k CCC: $20.00 © 2001 American Chemical Society
Publication on Web 03/17/2001

1
576 Organometallics, Vol. 20, No. 8, 2001
Reina et al.
Sch em e 1
the driving force to explain this result, it is not clear
why the AuPEt3 does not cap the Ru2W face instead of
the Ru3.
Bimetallic Au2(diphos)2 or trimetallic Au3(triphos)3+
cations as electrophilic species have been widely studied.
This is because such units can be bound to a cluster
+
6
7
8
anion through two gold atoms or can link two or three
cluster units together. The structure of the final product
9
strongly depends on the bite angle of the diphosphine.
With this in mind, we analyzed the reaction between
(
(
NEt4)2[Fe5MoC(CO)17] and (ClAu)2diphos (diphos ) bis-
diphenylphosphino)methane (dppm), 1,2-bis(diphen-
ylphosphino)ethane (dppe), and 1,3-bis(diphenylphos-
phino)propane (dppp)) (Scheme 1). We found that for
(
ClAu)2diphos (diphos ) dppe, dppp), the resulting
species were (NEt4)2[{Fe5MoAuC(CO)17}2 (dppe)], (NEt4)2-
3], and (NEt4)2[{Fe5MoAuC(CO)17}2(dppp)], (NEt4)2[4],
[
in which two “Fe5MoAuC(CO)17” are linked by the
corresponding diphosphine, according to the IR and
NMR spectroscopies and electrospray mass spectrom-
etry. However, the X-ray crystal structure determina-
tion of dppm derivative revealed the neutral compound
F igu r e 1. ORTEP view of the molecular structure of the
anionic cluster 2 with the atomic numbering scheme. The
thermal ellipsoids are drawn at the 50% probability level.
(
6) (a) Rossell, O.; Seco, M.; Segal e´ s, G.; Pellinghelli, M. A.; Tiri-
[Fe5MoAu2C(CO)17(dppm)], 5. Its molecular structure is
illustrated in Figure 2, together with the atomic num-
bering scheme; the most significant bond distances and
angles are given in Table 2. The metal core geometry
can be described as an Fe5Mo octahedron in which an
Fe-Fe edge is bridged by one gold atom, whereas the
other is directly attached to the molybdenum center.
picchio, A. J . Organomet. Chem. 1998, 571, 123. (b) Akhter, Z.; Ingham,
S. L.; Lewis, J .; Raithby, P. R. J . Organomet. Chem. 1994, 474, 165.
c) Hattersley, A. D.; Housecroft, C. E.; Rheingold, A. L. Inorg. Chim.
Acta 1999, 289, 149. (d) Bates, P. A.; Brown, S. S. D.; Dent, A. J .;
Hursthouse, M. B.; Kitchen, G. F. M.; Orpen, A. G.; Salter, I. A.; Sik,
V. J . Chem. Soc., Chem. Commun. 1986, 600. (e) Albano, V. G.;
Iapalucci, M. C.; Longoni, G.; Manzi, L.; Monari, M. Organometallics
997, 16, 497. (f) Collins, C. A.; Salter, I. D.; Sik, V.; Williams, S. A.;
Adatia, T. J . Chem. Soc., Dalton Trans. 1998, 1107. (g) Bruce, M. I.;
Horn, H.; Humphrey, P. A.; Tiekink, E. R. T. J . Organomet. Chem.
(
1
2
+
This surprising coordination mode of the Au2(dppm)
1
996, 518, 121.
7) (a) Rossell, O.; Seco, M.; Reina, R.; Font-Bard ´ı a, M.; Solans, X.
3
2
moiety (µ -η ) to the cluster anion has no precedent in
(
2
+
the literature; the Au2(dppm) units are usually at-
Organometallics 1994, 13, 2127. (b) Rossell, O.; Seco, M.; Segal e´ s, G.
J . Organomet. Chem. 1995, 503, 225. (c) Low, P. M. N.; Tan, A. L.;
Hor, T. S. A.; Wen, Y. S.; Liu, L. K. Organometallics 1996, 15, 2595.
tached to metal clusters through two µ2- or µ3-bonding
6,7
modes. The average distances between Fe(1)-Fe(4)
(
d) Ferrer, M.; J uli a` , A.; Reina, R.; Rossell, O.; Seco, M.; de Montauzon,
D. J . Organomet. Chem. 1998, 560, 147.
8) Ferrer, M.; J uli a` , A.; Rossell, O.; Seco, M.; Pellinghelli, M. A.;
Tiripicchio, A. Organometallics 1997, 16, 3715.
9) Alvarez, S.; Rossell, O.; Seco, M.; Valls, J .; Pellinghelli, M. A.;
Tiripicchio, A. Organometallics 1991, 10, 2309.
and the carbide fall in the range 1.880(7)-1.949(7) Å,
whereas the Fe(3)-C and the Mo-C lengths are some-
what higher, 2.023(10) and 2.058(10) Å, respectively.
C(3)-O(3) and C(19)-(O19) are semibridging along the
(
(

Electrophilic Additions to Iron Carbide Clusters
Organometallics, Vol. 20, No. 8, 2001 1577
Ta ble 1. Selected Bon d Len gth s [Å] a n d An gles
[
4
d eg] for (NEt )[2]
Au-Fe(2)
Au-Fe(3)
Au-Mo
Mo-Fe(5)
Mo-Fe(4)
Mo-Fe(2)
Mo-Fe(3)
2.743(2)
2.747(1)
2.963(3)
2.784(1)
2.894(2)
2.952(2)
3.014(2)
Fe(1)-Fe(3)
Fe(1)-Fe(4)
Fe(1)-Fe(5)
Fe(1)-Fe(2)
Fe(2)-Fe(4)
Fe(2)-Fe(3)
Fe(3)-Fe(5)
Fe(4)-Fe(5)
2.623(2)
2.648(2)
2.676(2)
2.684(1)
2.569(2)
2.841(3)
2.698(3)
2.710(2)
P-Au-Fe(2)
P-Au-Fe(3)
Fe(2)-Au-Fe(3)
P-Au-Mo
Fe(2)-Au-Mo
Fe(3)-Au-Mo
Fe(5)-Mo-Au
Fe(4)-Mo-Au
Fe(4)-Fe(2)-Au
149.92(6)
141.15(7)
62.33(4)
137.54(6)
62.15(6)
63.59(3)
109.77(3)
107.14(6)
124.99(6)
Fe(1)-Fe(2)-Au
Fe(1)-Fe(2)-Mo
Au-Fe(2)-Mo
Fe(1)-Fe(3)-Au
Fe(5)-Fe(3)-Au
Fe(1)-Fe(3)-Mo
Au-Fe(3)-Mo
Fe(5)-C(1)-Fe(2)
Fe(3)-C(1)-Fe(4)
Fe(1)-C(1)-Mo
115.34(5)
91.47(4)
62.58(6)
117.27(5)
119.44(5)
91.29(8)
61.69(4)
172.9(5)
176.0(5)
175.6(5)
edge Mo-Au(1), and C(6)-O(6) is semibridging along
the edge Fe(2)-Au(2). This structural feature favors
short Au-C bond distances in the range 2.454(8)-2.680-
F igu r e 2. ORTEP view of the molecular structure of 5
with the atomic numbering scheme. The thermal ellipsoids
are drawn at the 50% probability level.
9) Å, as found in related metal clusters.10 It is interest-
(
ing to compare the structure of 5 with that found for
Fe4Au2C(CO)12(dppm)], which is the result of the reac-
Ta ble 2. Selected Bon d Len gth s [Å] a n d An gles
[d eg] for 5
[
2
-
1
tion between [Fe6C(CO)16] and (ClAu)2dppm. Forma-
tion of [Fe4Au2C(CO)12(dppm)] results from the partial
cleavage of the octahedral iron anion, whereas the
Au(1)-Au(2)
Au(2)-Fe(1)
Au(2)-Fe(2)
Mo-Fe(5)
2.8621(6)
2.680(1)
2.682(1)
2.885(1)
2.905(1)
2.946(1)
2.959(1)
Fe(1)-Fe(5)
Fe(1)-Fe(3)
Fe(1)-Fe(2)
Fe(2)-Fe(4)
Fe(2)-Fe(3)
Fe(3)-Fe(4)
Fe(3)-Fe(5)
Fe(4)-Fe(5)
2.654(1)
2.695(2)
2.877(1)
2.607(1)
2.641(1)
2.622(1)
2.673(2)
2.609(1)
2
-
presence of the molybdenum in [Fe5MoC(CO)17] seems
to stabilize the metal core against the formation of the
di-gold derivative.
Mo-Fe(4)
Mo-Fe(2)
Mo-Fe(1)
To extend our studies to other electrophilic species,
2
-
the anion [Fe5MoC(CO)17] was allowed to react with
P(1)-Au(1)-Mo
P(2)-Au(2)-Fe(1)
P(2)-Au(2)-Fe(2)
Fe(1)-Au(2)-Fe(2)
Au(1)-Mo-Fe(5)
Au(1)-Mo-Fe(4)
167.62(7) Au(2)-Fe(2)-Fe(1)
155.16(5) Fe(5)-C(1)-Fe(2)
136.36(7) Fe(4)-C(1)-Fe(1)
64.91(4) Fe(4)-C(1)-Mo
146.85(3) Fe(5)-C(1)-Mo
145.51(4) Fe(2)-C(1)-Mo
57.51(3)
169.3(6)
168.7(5)
95.0(3)
93.5(4)
96.1(3)
IM(PPh3) (M ) Ag, Cu), ClHgMo(CO)3Cp, and ClHgW-
(CO)3Cp. The reaction was monitored by IR spectroscopy
in the ν(CO) region and was completed after 1 h. The
new compounds (NEt4)[Fe5MoMC(CO)17(PPh3)] (M )
Cu, (NEt4)[6]; M ) Ag, (NEt4)[7]), (NEt4)[Fe5MoHgMoC-
Fe(5)-Fe(1)-Au(2) 131.94(4) Fe(1)-C(1)-Mo
Au(2)-Fe(1)-Fe(3) 110.71(5) Fe(3)-C(1)-Mo
95.2(4)
(
(
CO)20Cp], (NEt4)[8], and (NEt4)[Fe5MoHgWC(CO)20Cp],
NEt4)[9], were characterized by ESMS and NMR
179.1(4)
170.2(8)
172.3(8)
Au(2)-Fe(1)-Fe(2)
Fe(4)-Fe(2)-Au(2) 133.46(7) O(19)-C(19)-Mo
Fe(3)-Fe(2)-Au(2) 112.32(5)
57.58(3) O(3)-C(3)-Mo
spectroscopy. Although from the spectroscopic data it
is not possible to deduce the site of attachment of the
+
MPPh3 and the mercury fragments units to the start-
-
[
Fe6C(CO)16]2 stabilizes the resulting mixed-metal
ing anion, the similarity of the pattern in the ν(CO) IR
region displayed for the latter derivatives to that
exhibited for (NEt4)[1] and (NEt4)[2] indicate that they
have the same metal skeleton, which is consistent with
2
-
cluster anion [Fe5MoC(CO)17] . Consequently, the lat-
ter anion does not exhibit cleavage during the reaction
with the di-gold complex (ClAu)2dppm and the final
2
compound displays an unprecedented (µ3-η ) Au2-
1
1
+
the isolobal analogy between AuPPh3 and HgMo(CO)3-
2
+
(
dppm) bonding mode.
+
Cp , which has been illustrated in a large series of
1
2
compounds.
Exp er im en ta l Section
All manipulations were performed under prepurified N2
In conclusion, we have shown that the heteronuclear
anion [Fe5MoC(CO)17]2- incorporates only one electro-
philic metal fragment, which caps an Fe2Mo triangular
face, in contrast to the cluster [Ru5WC(CO)17]2 , which
reacts with two metal fragments using the Ru3 trian-
gular faces. On the other hand, the substitution of an
Fe(CO)3 for an Mo(CO)5 fragment in the cluster
using standard Schlenk techniques. All solvents were distilled
from appropriate drying agents. Infrared spectra were recorded
in THF solutions on an FT-IR 520 Nicolet spectrophotometer.
-
3
1
1
1
13
P{ H} NMR (δ (85% H
3 4
PO ) ) 0.0 ppm), H NMR, and C-
{1
H} NMR (δ (TMS) ) 0.0 ppm) spectra were obtained on
Bruker DXR 250 and Varian 200 spectrometers. Elemental
analyses of C, H, and N were carried out at the Institut de
Bio-Org a` nica in Barcelona. FAB(-) and electrospray mass
spectra were recorded on a Fisons VG Quattro spectrometer
(
10) (a) Simon, F. E.; Lauher, J . W. J . Am. Chem. Soc. 1980, 19,
2
338. (b) Byers, P. K.; Carr, N.; Stone, F. G. J . Chem. Soc., Dalton
Trans. 1990, 3701. (c) Blum, T.; Braunstein, P.; Tiripicchio, A.;
Tiripicchio Camellini, M. New. J . Chem. 1988, 12, 539. (d) Housecroft,
C. E.; Matthews, D. M.; Rheingold, A. L. Organometallics 1992, 11,
with methanol as the solvent. The compounds (NEt
4
)
2
[Fe
5
-
-
1
3
14
15
16
MoC(CO)17], ClAuPPh
3
,
IAgPPh
3
,
ICuPPh
3
,
ClHgMo(CO)
3
2
1
959. (e) Edelman, F.; T o¨ fke, S.; Behrens, U. J . Organomet. Chem.
986, 309, 87.
(
(
11) Lauher, J . W.; Wald, K. J . Am. Chem. Soc. 1981, 103, 7648.
12) Ferrer, M.; Reina, R.; Rossell, O.; Seco, M. Coord. Chem. Rev.
(13) Tachikawa, M.; Geerts, R. L.; Muetterties, E. L. J . Organomet.
Chem. 1981, 213, 11.
1
999, 193-195, 619.
(14) Kowala, C.; Swan, J . M. Aust. J . Chem. 1966, 19, 547.

1
578 Organometallics, Vol. 20, No. 8, 2001
Ta ble 3. Cr ysta l Da ta a n d Str u ctu r e Refin em en t for Com p ou n d s (NEt
Reina et al.
4
)[2] a n d 5
5
(NEt4)[2]
empirical formula
fw
C29H29AuFe5MoNO17P
1266.66
C43H22Au2Fe5MoO17P2
1641.67
temp (K)
wavelength (Å)
cryst syst
space group
a (Å)
293(2)
0.710 69
monoclinic
P21/c
9.563(11)
34.989(4)
12.294(9)
90
92.63(7)
90
4109(6)
4
2.047
5.673
293(2)
0.710 69
monoclinic
P21/c
10.8220(10)
25.7800(10)
17.8930(10)
90
104.1130(10)
90
4841.3(6)
4
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
3
V (Å )
Z
3
density (calcd) (g/cm )
2.252
7.876
-
1
abs coeff (mm
)
F(000)
2448
3104
cryst size (mm)
Θ range for data collection (deg)
index ranges
0.1 × 0.1 × 0.2
0.1 × 0.1 × 0.2
2.03-29.98
1.94-25.01
-13 < h < 13, 0 < k < 42, 0 < l < 17
12 193
-7 < h < 7, 0 < k < 30, 0 < l < 20
15 460
no. rflns collected
no. indep rflns
11651 (Rint ) 0.0511)
5281 (Rint ) 0.0654)
refinement method
no. data/restraints/params
full-matrix least squares on F2
11651/10/244
0.916
5281/72/631
0.869
2
GOF on F
final R indices [I > 2 σ(I)]
R1 ) 0.0445, wR2 ) 0.1185
R1 ) 0.1191, wR2 ) 0.1481
0.721 and -0.849
R1 ) 0.0268, wR2 ) 0.0442
R1 ) 0.0803, wR2 ) 0.0496
0.623 and -0.624
R indices (all data)
3
largest diff peak and hole (e/Å )
31
1
Cp, and ClHgW(CO)
previously. The complexes (ClAu)
ClAu) (dppp) were synthesized and isolated as solids from
ClAu(tht) solutions
the corresponding phosphine.
Syn th eses of (NEt )[1], (NEt
Solid ClAuPPh (0.16 g, 0.31 mmol) and TlBF
mmol) were added to a precooled (-5 °C) solution of (NEt
3
Cp17 were synthesized as described
(dppm), (ClAu) (dppe), and
cm-1): ν(CO) 2048 (m), 1990 (vs), 1965 (sh). P{ H} NMR (298
1
2
2
K, CH
2
Cl
2
, δ(ppm)): 0.2 (s, PPh
3
). H NMR (298 K, CD
2
Cl
, J (H-H) ) 7.50 Hz),
, J (H-H) ) 6.25 Hz). C NMR (298 K, CD Cl , δ
2
, δ
3
(
2
(ppm)): 7.50-7.54 (m, Ph), 3.17 (q, CH
1.36 (t, CH
2
9
,18
3
13
by adding the appropriate amount of
3
2
2
(ppm)): 475.65 (s, C), 221.02 (s, CO), 133.10-128.00 (m, Ph),
-
4
4
)[2], (NEt
4
)[6], (NEt
(0.09 g, 0.31
[Fe
4
)[7].
53.30 (s, CH
2
), 7.14 (s, CH
3
). ESMS (M ) m/z: calcd, 1189;
3
4
found, 1190. Anal. Calcd: C, 40.04; H, 2.65; N, 1.06. Found:
C, 40.10; H, 2.69; N, 1.13. (NEt )[Fe MoC(CO)17{AgPPh }]:
yield, 0.25 g (58%). IR (THF, cm ): ν(CO) 2047 (m), 1988 (vs),
4
)
2
5
-
4
5
3
-1
MoC(CO)17] (0.36 g, 0.31 mmol) in 40 mL of THF. The reaction
was monitored by IR, and after 1 h of stirring the salts (TlCl
3
1
1
2 2
1967 (sh). P{ H} NMR (298 K, CH Cl , δ (ppm)): 13.2 (d,
PPh
K, CD
H) ) 7.50 Hz), 1.30 (t, CH
(298 K, CD Cl , δ (ppm)): 221.16 (s, CO), 133-128 (m, Ph),
3
, J (1 Ag-P) ) 526.5, J ( Ag-P) ) 456.6). H NMR (298
09
107
1
and NEt
4
BF
4
) were filtered off. Subsequent addition of 20 mL
3
of diethyl ether and cooling 2 h at -30 °C afforded more salts.
Then it was filtered through Celite and the solution was
evaporated to dryness. The remaining solid was extracted with
2
Cl
2
, δ(ppm)): 7.39-7.51 (m, Ph), 3.11 (q, CH
2
13
, J (H-
3
3
, J (H-H) ) 6.25 Hz). C NMR
2
2
-
CH
solution was cooled to -30 °C overnight to induce the forma-
tion of the dark-red crystalline solid (NEt )[1]. Yield: 0.27 g
2
Cl
2
(10 mL), and hexane (8 mL) was added. The resulting
2 3
53.20 (s, CH ), 7.19 (s, CH ). ESMS (M ) m/z: calcd, 1233;
found, 1234. Anal. Calcd: C, 38.68; H, 2.60; N, 1.03. Found:
C, 38.72; H, 2.73; N, 1.09.
4
-
1
31
1
(
57%). IR (THF, cm ): ν(CO) 2047 (m), 1991 (vs). P{ H}
Syn th eses of (NEt
synthesis of (NEt )[8] also apply to the synthesis of (NEt
To a precooled solution of (NEt [Fe MoC(CO)17] (0.31 g, 0.27
mmol) in THF (50 mL) at -5 °C, solid ClHgMo(CO) Cp (0.13
g, 0.27 mmol) and TlBF (0.08 g, 0.27 mmol) were added. The
4
)[8] a n d (NEt
4
)[9]. Details of the
1
NMR (298 K, CH
K, CD Cl , δ (ppm)): 7.50-7.48 (m, Ph), 3.11 (q, CH
H) ) 7.50 Hz), 1.36 (t, CH
2
Cl
2
3
, δ (ppm)): 55.5 (s, PPh ). H NMR (298
4
4
)[9].
3
2
2
2
, J (H-
4
)
2
5
3
13
3
, J (H-H) ) 6.25 Hz). C NMR
3
(
298 K, CD
2
Cl
2
, δ (ppm)): 221.62 (s, CO), 134.08-129.24 (m,
), 7.39 (s, CH
4
-
Ph), 53.63 (s, CH
2
3
). ESMS (M ) m/z: calcd, 1322;
mixture was stirred for 2 h, and 15 mL of diethyl ether were
added to ensure the total precipitation of the salts (TlCl and
found, 1324. Anal. Calcd: C, 36.34; H, 2.41; N, 0.96. Found:
C, 36.39; H, 2.46; N, 1.02.
NEt
4
BF
4
). After filtration the remaining solution was taken
Cl (10 mL). Addition of
Compounds (NEt
tained by a similar procedure, but a molar ratio of 1:2:2 was
used for (NEt )[2] and a ratio of 1:1.5:1.5 was used for (NEt )-
6] instead of 1:1:1. (NEt )[Fe MoC(CO)17{AuPMe }]: yield,
.22 g (54%). IR (THF, cm ): ν(CO) 2046 (m), 1989 (vs), 1961
4 4 4
)[2], (NEt )[6], and (NEt )[7] were ob-
to dryness and extracted with CH
2
2
4
pentane (7 mL) by slow diffusion at -30 °C afforded (NEt )[8]
4
4
-1
as a dark-red solid. Yield: 0.23 g (49%). IR (THF, cm ): ν(CO)
[
0
4
5
3
056 (m), 2002 (vs), 1982 (s). 1H NMR (298 K, CD
2
2
Cl
2
, δ
-
1
3
(
(
(
(
ppm)): 5.49 (s, Cp), 3.22 (q, CH
t, CH
2
13
, J (H-H) ) 7.50 Hz), 1.36
J (H-H) ) 6.25 Hz). C NMR (298 K, CD
ppm)): 220.02 (s, CO), 89.21 (s, 5H, Cp), 53.73 (s, CH
). ESMS (M ) m/z: calcd, 1309; found, 1308. Anal.
Calcd: C, 28.36; H, 1.74; N, 0.97. Found: C, 28.47; H, 1.79;
3
MoC(CO)17{HgW(CO) Cp}]: yield, 0.23 g
47%). IR (THF, cm ): ν(CO) 2056 (m), 2001 (vs), 1982 (s).
3
1
1
1
(
s). P{ H} NMR (298 K, CH
NMR (298 K, CD Cl , δ (ppm)): 3.10 (q, CH
Hz), 1.58 (d, P(CH 3, J (C-P) ) 8.26), 1.29 (t, CH
6.25 Hz). C NMR (298 K, CD Cl , δ (ppm)): 221.86 (s, CO),
3.31 (s, CH ) 17.60 (d, P(CH , J (P-C) ) 31.45), 7.19 (s, CH ).
ESMS (M ) m/z: calcd, 1136; found, 1136. Anal. Calcd: C,
7.49; H, 2.30; N, 1.11. Found: C, 27.52; H, 2.35; N, 1.13.
NEt )[Fe MoC(CO)17{CuPPh }]: yield, 0.23 g (55%). IR (THF,
2
Cl
2
, δ (ppm)): 16.5 (s, PPh
3
). H
3
3
,
2
Cl
), 7.62
2
, δ
3
2
2
2
, J (H-H) ) 7.50
2
3
3
)
3
, J (H-H)
-
s, CH
3
1
3
)
5
2
2
2
3
)
3
3
N, 1.08. (NEt
(
4
)[Fe
5
-
-1
2
(
1
H NMR (298 K, CD
2
Cl
2
, δ (ppm)): 5.46 (s, 5H, Cp), 3.22 (q,
4
5
3
3
3
CH
2
, J (H-H) ) 7.50 Hz), 1.36 (t, CH , J (H-H) ) 6.25 Hz).
3
1
3
C NMR (298 K, CD
Cp), 54.00 (s, CH
2
Cl
2
, δ (ppm)): 220.28 (s, CO), 88.15 (s,
(15) Teo, B. K.; Calabrese, J . Inorg. Chem. 1976, 15, 2474.
(16) Kauffman, B. B.; Teter, L. A. Inorg. Synth. 1963, 7, 9.
(17) Mays, M. J .; Robb, J . D. J . Chem. Soc. A 1968, 329.
(18) Us o´ n, R.; Laguna, A. Organomet. Synth. 1986, 3, 324.
-
2
), 7.92 (s, CH
3
). ESMS (M ) m/z: calcd, 1397;
found, 1397. Anal. Calcd: C, 26.73; H, 1.64; N, 0.92. Found:
C, 26.79; H, 1.69; N, 1.01.

Electrophilic Additions to Iron Carbide Clusters
Organometallics, Vol. 20, No. 8, 2001 1579
Syn t h esis of [F e
ClAu) dppm (0.22 g, 0.26 mmol) and TlBF
were added to a solution of (NEt [Fe MoC(CO)17] (0.28 g, 0.25
mmol) in THF (35 mL). The mixture was stirred for 17 h at 0
C, and the salts (TlCl and NEt BF ) were filtered off. The
solution was concentrated to dryness, and the residual solid
was extracted with CH Cl (8 mL). Slow layer diffusion of
hexane (8 mL) at -30 °C afforded deep-red crystals of 5.
5
Mo Au
2
C(CO)17(d p p m )] (5). Solid
Hz). ESMS (M2-/2) m/z: calcd, 1259; found, 1259. Anal. Calcd:
C, 33.69; H, 2.30; N, 1.01. Found: C, 33.81; H, 2.38; N, 1.04.
(
2
4
(0.09 g, 0.31 mmol)
4
)
2
5
X-r a y Str u ctu r e Deter m in a tion of (NEt )[2] a n d 5. Red
4
block crystals of compounds (NEt )[2] and 5 were selected and
4
°
4
4
mounted on an Enraf-Nonius CAD4 four-circle diffractometer.
Crystallographic and experimental details of both compounds
are summarized in Table 3. Data were collected at room
temperature. Intensities were corrected for Lorentz and
polarization effects in the usual manner.
2
2
-
1
Yield: 0.17 g (54%). IR (THF, cm ): ν(CO) 2059 (m), 2009
3
1
1
(
(
Cl
2 2
vs), 1979 (s). P{ H} NMR (298 K, CH Cl , δ (ppm)): 44.2
The structures were solved by direct methods, using the
SHELXS computer program, and were refined by a full-matrix
1
2
d), 50.4 (d) (dppm, J (P-P) ) 74.3 Hz). H NMR (298 K, CD -
2
, δ (ppm)): 7.66-7.17 (m, Ph), 3.22 (t, CH
2
, J (H-P) ) 9.19).
19
2
least-squares method with the SHELX97 computer program.
-
FABMS (M ) m/z: calcd, 1641; found, 1640. Anal. Calcd: C,
2
2 2
2
The function minimized was ∑w||F
o
| - |F
c
| | , where w ) [σ (I)
3
1.44; H, 1.34. Found: C, 31.49; H, 1.38.
Syn th eses of (NEt [3] a n d (NEt
thesis of (NEt [4] also apply to (NEt
0.12 g, 0.14 mmol) and TlBF (0.08 g, 0.27 mmol) were added
to a solution of (NEt [Fe MoC(CO)17] (0.30 g, 0.27 mmol) in
THF (40 mL) at -10 °C. The mixture was stirred for 30 min,
and the salts (TlCl and NEt BF ) were filtered off. The
resulting solution was then concentrated to dryness. The
residue was extracted with CH Cl (10 mL), and hexane (8
mL) was added. A dark-red solid was obtained in 51% yield
2
-1
2
2
+
(0.0774P) ] and P ) (|F | + 2|F
o
c
| )/3, and f, f ′, and f ′′ were
)
2
4
)
2
[4]. Details of syn-
20
4
taken from International Tables for X-Ray Crystallography.
4
)
2
4
)
2
[3]. Solid (ClAu) dppp
2
All H atoms were computed and refined with an overall
isotropic temperature factor equal to 1.2 times the equivalent
isotropic temperature factor of the atom and are linked using
a riding model.
(
4
4
)
2
5
4
4
Ack n ow led gm en t. Financial support for this work
was generously given by DGICYT through Grant PB96-
0174 and the CIRIT (Project 1999 SGR00045). We thank
G. Segal e´ s for fruitful discussions.
2
2
-1
(
0.19 g). IR (THF, cm ): ν(CO) 2047 (m), 1991 (vs), 1965 (sh).
3
1
1
, δ (ppm)): 26.7 (s, dppp). 1
P{ H} NMR (298 K, CH
NMR (298 K, CD Cl
J (H-H) ) 7.50 Hz), 2.65 (m, CH
2
Cl
2
H
2
2
, δ(ppm)): 7.30-7.61 (m, Ph), 3.20 (q, CH
CH P), 1.91 (m, CH CH P),
, J (H-H) ) 6.25 Hz). C NMR (298 K, CD
δ(ppm)): 221.41 (s, CO), 132.75-129.35 (m, Ph), 53.30 (s, CH
CH ), 28.09 (dd, CH CH P), 23.27 (d, CH CH P), 7.92 (s, CH
ESMS (M /2) m/z: calcd, 1266; found, 1267. Anal. Calcd: C,
3.95; H, 2.36; N, 1.00. Found: C, 34.05; H, 2.39; N, 1.04.
NEt [{Fe MoAuC(CO)17 (dppe)]: reaction temperature
was -10 °C and reaction time 2 h. Yield: 0.23 g (52%). IR
2
,
3
2
2
2
2
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data, atomic coordinates, thermal parameters, and bond
3
13
1
.35 (t, CH
3
2
Cl
2
2
,
-
distances and angles for compounds (NEt )[2] and 5. This
4
material is available free of charge via the Internet at
http://pubs.acs.org.
3
2
2
2
2
3
).
2
-
3
OM000976K
(
4
)
2
5
}
2
-
1
31
1
(19) Sheldrick, G. M. SHELXS: A computer program for determi-
nation of crystal structure; University of G o¨ ttingen: G o¨ ttingen,
Germany.
(THF, cm ): ν(CO) 2047 (m), 1991 (vs), 1966 (sh). P{ H}
1
NMR (298 K, CH
K, CD Cl , δ (ppm)): 7.59-7.46 (m, Ph), 3.21 (q, CH
H) ) 7.50 Hz), 2.75 (s, CH
2 2
Cl , δ (ppm)): 53.3 (s, dppe). H NMR (298
3
2
2
2
, J (H-
3
P), 1.36 (t, CH , J (H-H) ) 6.25
(
20) International Tables for X-Ray Crystallography; Kynoch
3
2
Press: Birmingham, 1974; Vol. IV, pp 99-100, 149.