Remarkable reactions of cationic carbyne complexes of manganese and rhenium with diiron anions [Fe2(μ-CO)(μ-SeR)(CO)6]-. A route to RSe-bridged dimetal bridging carbene complexes

Article abstract of DOI:10.1021/om001035a

The reactions of cationic carbyne complexes of manganese and rhenium, [η-C₅H₅(CO)₂M≡CC₆ H₅]BBr₄ (1, M = Mn; 2, M = Re), with diiron anionic compounds [Et₃NH][Fe₂(μ-CO) (μ-SeR)(CO)₆] (3, R = C₆H₅; 4, R = p-CH₃C₆H₄) in THF at low temperature gave the dimetal bridging carbene complexes [MFe{μ-C(SeR)C₆H₅} (CO)₅(η-C₅H₅)] (10, M = Mn, R = C₆H₅); 11, M = Mn, R = p-CH₃C₆H₄; 13, M = Re, R = C₆H₅; 14, M = Re, R = (p-CH₃C₆H₄), [η-C₅H₅M(CO)₃] (7, M = Mn; 12, M = Re), and [Fe₂(μ-SeR)₂(CO)₆] (8, R = C₆H₅; 9, R = p-CH₃C₆H₄). Complexes 1 and 2 also react with [MgBr][Fe₂(μ-CO) (μ-SeC₂H₅)(CO)₆] (5) to produce [Fe₂(μ-SeC₂H₅)₂(CO)₆] (15) and dimetal bridging carbene complexes [MnFe{μ-C(SeC₂H₅)C₆H₅} (CO)₅(η-C₅H₅)] (17) and [ReFe{μ-C(SeC₂H₅)C₆H₅} (CO)₅(η-C₅H₅)] (18), respectively. 2 reacts similarly with [MgBr][Fe₂(μ-CO)(μ-SeC₄H₉-n) (CO)₆] (6) to give [Fe₂(μ-SeC₄H₉-n)₂(CO)₆ ] (16) and a Re-Fe bridging carbene complex [ReFe{μ-C(SeC₄H₉-n)C₆H₅}(CO) ₅(η-C₅H₅)] (19), while the analogous reaction of 1 with 6 produced an unexpected trimetal bridging carbyne complex [MnFe₂(μ-H)(μ-CO)₂(μ₃ -CC₆H₅(CO)₆) (η-C₅H₅)] (20). The structures of complexes 9, 10, 13, 18, and 20 have been established by X-ray diffraction studies.

Full text of DOI:10.1021/om001035a

2226
Organometallics 2001, 20, 2226-2233
Rem a r k a ble Rea ction s of Ca tion ic Ca r byn e Com p lexes of
Ma n ga n ese a n d Rh en iu m w ith Diir on An ion s
[F e2(µ-CO)(µ-SeR)(CO)6]-. A Rou te to RSe-Br id ged
Dim eta l Br id gin g Ca r ben e Com p lexes
Ruitao Wang,† Qiang Xu,*,‡ Yoshie Souma,‡ Li-Cheng Song,§ J ie Sun,† and
J iabi Chen*,†
Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry,
Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China, National Institute of
Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda 563-8577, J apan,
and Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry,
Nankai University, Tianjin 300071, China
Received December 4, 2000
The reactions of cationic carbyne complexes of manganese and rhenium, [η-C5H5(CO)2Mt
CC6H5]BBr4 (1, M ) Mn; 2, M ) Re), with diiron anionic compounds [Et3NH][Fe2(µ-CO)(µ-
SeR)(CO)6] (3, R ) C6H5; 4, R ) p-CH3C6H4) in THF at low temperature gave the dimetal
bridging carbene complexes [MFe{µ-C(SeR)C6H5}(CO)5(η-C5H5)] (10, M ) Mn, R ) C6H5;
11, M ) Mn, R ) p-CH3C6H4; 13, M ) Re, R ) C6H5; 14, M ) Re, R ) p-CH3C6H4), [η-C5H5M-
(CO)3] (7, M ) Mn; 12, M ) Re), and [Fe2(µ-SeR)2(CO)6] (8, R ) C6H5; 9, R ) p-CH3C6H4).
Complexes 1 and 2 also react with [MgBr][Fe2(µ-CO)(µ-SeC2H5)(CO)6] (5) to produce [Fe2-
(µ-SeC2H5)2(CO)6] (15) and dimetal bridging carbene complexes [MnFe{µ-C(SeC2H5)C6H5}-
(CO)5(η-C5H5)] (17) and [ReFe{µ-C(SeC2H5)C6H5}(CO)5(η-C5H5)] (18), respectively. 2 reacts
similarly with [MgBr][Fe2(µ-CO)(µ-SeC4H9-n)(CO)6] (6) to give [Fe2(µ-SeC4H9-n)2(CO)6] (16)
and a Re-Fe bridging carbene complex [ReFe{µ-C(SeC4H9-n)C6H5}(CO)5(η-C5H5)] (19), while
the analogous reaction of 1 with 6 produced an unexpected trimetal bridging carbyne complex
[MnFe2(µ-H)(µ-CO)2(µ3-CC6H5)CO)6(η-C5H5)] (20). The structures of complexes 9, 10, 13, 18,
and 20 have been established by X-ray diffraction studies.
In tr od u ction
bridging carbene and carbyne complexes has used the
reactions of the highly electrophilic cationic carbyne
complexes of manganese and rhenium, [η-C5H5(CO)2Mt
CC6H5]BBr4 (M ) Mn, Re), with anionic carbonylmetal
compounds.7,8 We have recently also shown the novel
reaction of the reactive salts [Et3NH][Fe2(µ-CO)(µ-RS)-
(CO)6], developed by Seyferth and co-workers in the late
1980s, with [η-C5H5(CO)2MtCC6H5]BBr4 (M ) Mn, Re)
to give RS-bridged dimetal bridging carbene complexes
(eq 1).9 This offers a possibility for the preparation of
heteroatom-bridged bridging carbene complexes.
In view of the fact that metal-metal bonded cluster
complexes are well known to play an important role in
many catalytic reactions1,2 and that many dinuclear and
polynuclear metal complexes with a bridging carbene
and carbyne ligand are themselves metal clusters or the
precursors of metal cluster complexes, the chemistry of
transition metal bridging carbene and carbyne com-
plexes is an area of current interest. In this regard, we
are interested in developing the methodologies for the
synthesis of such complexes. Many dimetal bridging
carbene and carbyne complexes have been synthesized
by Stone and co-workers by reactions3,4 of carbene or
carbyne complexes with low-valent metal species or by
reactions5,6 of neutral or anionic carbyne complexes with
metal hydrides or cationic metal compounds. In our
laboratory, one of the methods for the preparation of
(4) (a) Ashworth, T. V.; Howard, J . A. K.; Laguna, M.; Stone, F. G.
A. J . Chem. Soc., Dalton Trans. 1980, 1593. (b) Carriedo, G. A.;
Howard, J . A. K.; Stone, F. G. A. J . Chem. Soc., Dalton Trans. 1984,
1555. (c) Garcia, M. E.; J effery, J . C.; Sherwood, P.; Stone, F. G. A. J .
Chem. Soc., Dalton Trans. 1987, 1209. (d) Busetto, L.; J effery, J . C.;
Mills, R. M.; Stone, F. G. A.; Went, M. J .; Woodward, P. J . Chem. Soc.,
Dalton Trans. 1983, 101.
(5) (a) Howard, J . A. K.; Mead, K. A.; Moss, J . R.; Navarro, R.; Stone,
F. G. A.; Woodward, P. J . Chem. Soc., Dalton Trans. 1981, 743. (b)
Hodgson, D.; Howard, J . A. K.; Stone, F. G. A.; Went, M. J . J . Chem.
Soc., Dalton Trans. 1985, 331.
(6) Pilotti, M. U.; Stone, F. G. A.; Topaloglu, L. J . Chem. Soc., Dalton
Trans. 1991, 1621.
† Shanghai Institute of Organic Chemistry.
‡ National Institute of Advanced Industrial Science and Technology.
§ Nankai University.
(1) Suess-Fink, G.; Meister, G. Adv. Organomet. Chem. 1993, 35,
41.
(2) (a)Gladfelter, W. L.; Roesselet, K. J . In The Chemistry of Metal
Cluster Complexes; Shriver, D. F., Kaesz, H. D., Adams, R. D., Eds.;
VCH: Weinheim, Germany, 1990; p 392. (b) Maire, G. In Metal
Clusters in Catalysis; Gates, B. C., Guczi, L., Knoezinger, H., Eds.;
Elsevier: Amsterdam, The Netherlands, 1986; p 509. (c) Dickson, R.
S.; Greaves, B. C. Organometallics 1993, 12, 3249.
(3) Stone, F. G. A. In Advances in Metal Carbene Chemistry;
Schubert, U., Ed.; Kluwer Academic Publishers: Dordrecht, The
Netherlands, 1989; p 11.
(7) (a) Chen, J .-B.; Yu, Y.; Liu, K.; Wu, G.; Zheng, P.-J . Organome-
tallics 1993, 12, 1213. (b) Yu, Y.; Chen, J .-B.; Chen, J .; Zheng, P.-J . J .
Chem. Soc., Dalton Trans. 1996, 1443.
(8) (a) Tang, Y.-J .; Sun, J .; Chen, J .-B. Organometallics 1999, 18,
4337. (b) Tang, Y.-J .; Sun, J .; Chen, J .-B. J . Chem. Soc., Dalton Trans.
1998, 931. (c) Tang, Y.-J .; Sun, J .; Chen, J .-B. J . Chem. Soc., Dalton
Trans. 1998, 4003. (e) Tang, Y.-J .; Sun, J .; Chen, J .-B. Organometallics
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10.1021/om001035a CCC: $20.00 © 2001 American Chemical Society
Publication on Web 05/02/2001

RSe-Bridged Dimetal Bridging Carbene Complexes
Organometallics, Vol. 20, No. 11, 2001 2227
nol,15 4-methylbenzeneselenol,15 [Et3NH][Fe2(µ-CO)(µ-SeC6H5)-
(CO)6] (3),11b [X][Fe2(µ-CO)(µ-SeC6H4CH3-p)(CO)6] (4, X )
Et3NH or MgBr),11b,16 [MgBr][Fe2(µ-CO)(µ-SeC2H5)(CO)6] (5),11b
and [MgBr][Fe2(µ-CO)(µ-SeC4H9-n)(CO)6] (6)16 were all pre-
pared by literature methods.
The IR spectra were measured on a Perkin-Elmer 983G
spectrophotometer. All 1H NMR spectra were recorded at
ambient temperature in acetone-d6 with TMS as the internal
reference using a Bruker AM-300 spectrometer. Electron
ionization mass spectra (EIMS) were run on a Hewlett-
Packard 5989A spectrometer. Melting points obtained on
samples in sealed nitrogen-filled capillaries are uncorrected.
R ea ct ion of [η-C5H 5(CO)2Mn tCC6H 5]BBr 4 (1) w it h
[Et3NH][F e2(µ-CO)(µ-SeC6H5)(CO)6] (3) To Give [η-C5H5-
Mn (CO)3] (7), [F e2(µ-SeC6H5)2(CO)6] (8), a n d [Mn F e{µ-
C(SeC6H5)C6H5}(CO)5(η-C5H5)] (10). To a solution of 0.81 g
(1.61 mmol) of Fe3(CO)12 in 50 mL of THF was added 0.17 mL
(1.60 mmol) of C6H5SeH and 0.25 mL (1.79 mmol) of Et3N with
stirring. The mixture was stirred at room temperature for 10
min, during which time the green solution turned brown-red.
The resulting solution of [Et3NH][Fe2(µ-CO)(µ-SeC6H5)(CO)6]
(3)11b was cooled to -100 °C and then poured rapidly onto 0.95
g (1.60 mmol) of freshly prepared 1 previously cooled to -100
°C with stirring. The reaction mixture was slowly warmed to
-80 °C and then stirred at -80 to -50 °C for 7 h, during which
time the brown-red solution turned dark brown. The resulting
mixture was evaporated to dryness under vacuum at -50 to
-40 °C, and the dark purple-red residue was chromatographed
on an alumina (neutral, 200-300 mesh) column (1.6 × 15-25
cm) at -25 °C with petroleum ether as the eluant. The orange
band which eluted first was collected, then a purple-red band
was eluted with petroleum ether/CH2Cl2 (20:1). A third dark
green band was eluted with petroleum ether/CH2Cl2/Et2O (10:
1:1). The solvents were removed from the above three eluates
under vacuum, and the residues were recrystallized from
petroleum ether/CH2Cl2 at -80 °C. From the first fraction,
0.016 g (5%, based on 1) of yellow crystals of 717 was obtained.
7 is a known compound and was identified by comparison of
its melting point and IR and 1H NMR spectra with those of
an authentic sample.17 From the second fraction, 0.23 g (24%,
based on 1) of red crystals of 818 was obtained: mp 104 °C dec
(lit.18 94-96 °C dec); IR (CH2Cl2) ν(CO) 2067 (s), 2031 (vs),
1993 (vs) cm-1 (lit.18 (cyclohexane) 2061, 2031, 1998, 1991
cm-1); 1H NMR (CD3COCD3) δ 7.49-7.14 (m, 10H, C6H5); MS
In the meantime, we have noted the applications of
the [Fe2(µ-CO)(µ-SeR)(CO)6]- anions, the selenium ana-
logue of reactive [Fe2(µ-CO)(µ-SR)(CO)6]- anions, in
organometallic chemistry.10,11 In their reactions the Fe-
Fe and Fe-Se bonds are retained, and the bridging CO
usually is replaced by an another bridging ligand.
Although these reactive [Fe2(µ-CO)(µ-SeR)(CO)6]- an-
ions have been extensively investigated, their reactions
with cationic carbyne complexes have not been reported.
To explore and compare the reactivity of the [Fe2(µ-CO)-
(µ-SeR)(CO)6]- anions toward the cationic carbyne
complexes of manganese and rhenium, and to further
examine the scope of the new method for preparation
of dimetal bridging carbene and bridging carbyne
complexes, we have studied the reactions of cationic
carbyne complexes of manganese and rhenium, [η-C5-
H5(CO)2MntCC6H5]BBr4 (1) and [η-C5H5(CO)2Ret
CC6H5]BBr4 (2), with the diiron [Fe2(µ-CO)(µ-SeR)-
(CO)6]- anions, which afforded a series of novel RSe-
bridged heteronuclear dimetal bridging carbene or a
trimetal bridging carbyne complexes. We describe in this
paper these unusual reactions and the structures of the
resulting products.
Exp er im en ta l Section
All reactions were performed under a dry, oxygen-free N2
atmosphere using standard Schlenk techniques. All solvents
employed were of reagent grade and dried by refluxing over
appropriate drying agents and stored over 4 Å molecular sieves
under N2. Tetrahydrofuran (THF) and diethyl ether (Et2O)
were distilled from sodium benzophenone ketyl, while petro-
leum ether (30-60 °C) and CH2Cl2 were distilled from CaH2.
Neutral alumina (Al2O3) was deoxygenated under high vacuum
for 16 h, deactivated with 5% w/w N2-saturated water, and
stored under N2. Complexes [η-C5H5(CO)2MntC C6H5]BBr4
(1)12 and [η-C5H5(CO)2RetCC6H5]BBr4 (2)13 were prepared as
previously described. Compounds Fe3(CO)12,14 benzenesele-
m/e 594 (M+), 566 [M+ - CO], 538 [M+ - 2CO], 510 [M+
-
3CO], 482 [M+ - 4CO], 454 [M+ - 5CO], 426 [M+ - 6CO].
Anal. Calcd for C18H10O6Se2Fe2: C, 36.53; H, 1.70. Found: C,
36.53; H, 1.90. From the third fraction, 0.59 g (66%, based on
1) of 10 as blackish green crystals was obtained: mp 82 °C
dec; IR (CH2Cl2) ν(CO) 2042 (vs), 1978 (s), 1940 (vs, br), 1888
(m), 1788 (m) cm-1 1H NMR (CD3COCD3) δ 7.80-7.09 (m,
;
10H, C6H5), 4.65 (s, 5H, C5H5); MS m/e 562 [M+], 534 [M+
-
CO], 506 [M+ - 2CO], 478 [M+ - 3CO], 450 [M+ - 4CO], 422
[M+ - 5CO], 158 [C6H5SeH+]. Anal. Calcd for C23H15O5-
SeMnFe: C, 49.23; H, 2.69. Found: C, 49.56; H, 2.72.
R ea ct ion of 1 w it h [E t 3NH][F e2(µ-CO)(µ-SeC6H 4CH 3-
p)(CO)6] (4) To Give 7, [F e2(µ-SeC6H4CH3-p)2(CO)6] (9),
a n d [Mn F e{µ-C(SeC6H 4CH 3-p )C6H 5}(CO)5(η-C5H 5)] (11).
Compound 1 (0.95 g, 1.60 mmol) was treated, as used in the
reaction of 1 with 3, with [Et3NH][Fe2(µ-CO)(µ-SeC6H4CH3-
p)(CO)6] (4)11b prepared (in situ) by reaction of 0.880 g (1.75
mmol) of Fe3(CO)12 in 50 mL of THF with 0.302 g (1.76 mmol)
(9) Qiu, Z.-L.; Sun, J .; Chen, J .-B. Organometallics 1998, 17, 600.
(10) Song, L.-C. Trends Organomet. Chem. 1999, 3, 1.
(11) (a) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J .; Mak, T. C.
W. Organometallics 1995, 14, 5513. (b) Song, L.-C.; Yan, C.-G.; Hu,
Q.-M.; Wang, R.-J .; Mak, T. C. W.; Huang, X.-Y. Organometallics 1996,
15, 1535. (c) Song, L.-C. Yan, C.-G.; Hu, Q.-M.; Wu, B.-M.; Mak, T. C.
W. Organometallics 1997, 16, 632. (d) Song, L.-C.; Lu, G.-L.; Hu, Q.-
M.; Qin, X.-D.; Sun, C.-X.; Yang, J .; Sun, J . J . Organomet. Chem. 1998,
571, 55. (e) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Sun, J . Organometallics
1999, 18, 2700. (f) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Fan, H.-T.; Chen,
Y.; Sun, J . Organometallics 1999, 18, 3258..
(15) Foster, D. G. Organic Syntheses; Wiley: New York, 1955; Vol.
3, p 771.
(12) Fischer, E. O.; Meineke, E. W.; Kreissl, F. R. Chem. Ber. 1977,
110, 1140.
(13) Fischer, E. O.; Chen, J .-B.; Scherzer, K. J . Organomet. Chem.
1983, 253, 231.
(16) Coleman, G. H.; Craig, D. Organic Synthyses; J ohn Wiley &
Sons Inc.: New York, 1943; Collect. Vol. 2, p 179.
(17) Piper, T. S.; Cotton, F. A.; Wilkinson, G. J . Inorg. Nucl. Chem.
1955, 1, 165.
(14) King, R. B. Organometallic Syntheses: Transition-Metal Com-
pounds; Academic Press: New York, 1965; Vol. 1, p 95.
(18) Schermer, E. D.; Baddley, W. H. J . Organomet. Chem. 1971,
30, 67.

2228 Organometallics, Vol. 20, No. 11, 2001
Wang et al.
of p-CH3C6H4SeH and 0.26 mL (1.83 mmol) of Et3N, at -100
to -45 °C for 7-8 h. Further treatment as in the reaction of
1 with 3 gave 0.019 g (6%, based on 1) of yellow crystals of 7,
0.25 g (25%, based on 1) of red crystals of 9,11a and 0.58 g (63%,
based on 1) of blackish green crystals of 11. 7 was identified
by comparison of its mp and IR and 1H NMR spectra. 9: mp
122-123 °C; IR (CH2Cl2) ν(CO) 2066 (s), 2030 (vs), 1992 (vs)
Rea ction of 1 w ith [MgBr ][F e2(µ-CO)(µ-SeC2H5)(CO)6]
(5) To Give [F e2(µ-SeC2H5)2(CO)6] (15) a n d [Mn F e{µ-C-
(SeC2H5)C6H5}(CO)5(η-C5H5)] (17). A Schlenk flask was
charged with 0.140 g (1.77 mmol) of selenium powder, 20 mL
of THF, and 1.80 mmol of Grignard reagent C2H5MgBr in THF.
The mixture was stirred at room temperature for 20 min, and
at this time the selenium powder completely disappeared to
give a colorless solution. To this solution was added 0.888 g
(1.76 mmol) of Fe3(CO)12, and the mixture was stirred at room
temperature for 30 min, resulting in formation of a brown-
red solution of the salt [MgBr][Fe2(µ-CO)(µ-SeC2H5)(CO)6]
(5),11b which was cooled to -100 °C and then poured rapidly
onto 0.95 g (1.60 mmol) of freshly prepared 1 previously cooled
to -100 °C with vigorous stirring. Immediately the brown-
red solution turned dark brown. The reaction mixture was
slowly warmed to -80 °C and then stirred at -80 to -50 °C
for 6-7 h. Further treatment of the resulting mixture as in
the reaction of 1 with 3 gave 0.150 g (19%, based on 1) of red
crystals of 1520 and 0.585 g (72%, based on 1) of 17. Product
15 is a red viscous oil at room temperature: IR (CH2Cl2) ν(CO)
2061 (s), 2025 (vs), 1985 (vs) cm-1 (lit.20 (KBr) 2060 (vs), 2020
(vs), 1985 (vs) cm-1); 1H NMR (CD3COCD3) δ 2.75 (m, 4H,
1
cm-1; H NMR (CD3COCD3) δ 7.36-7.07 (m, 8H, C6H4CH3),
2.28 (s, 3H, C6H4CH3), 2.06 (s, 3H, C6H4CH3); MS m/e 622 (M+),
566 [M+ - 2CO], 538 [M+ - 3CO], 510 [M+ - 4CO], 482
[M+ - 5CO], 454 [M+ - 6CO]. Anal. Calcd for C20H14O6Se2-
Fe2: C, 38.75; H, 2.28. Found: C, 38.95; H, 2.32. 11: mp 101-
102 °C dec; IR (CH2Cl2) ν(CO) 2042 (vs), 1978 (s), 1937 (s, br),
1882 (m) cm-1 1H NMR (CD3COCD3) δ 7.80-6.90 (m, 9H,
;
C6H5 + C6H4CH3), 4.64 (s, 5H, C5H5), 2.18 (s, 3H, C6H4CH3);
MS m/e 576 [M+], 548 [M+ - CO], 520 [M+ - 2CO], 492
[M+ - 3CO], 464 [M+ - 4CO], 436 [M+ - 5CO], 172 [C6H5-
SeH+]. Anal. Calcd for C24H17O5SeMnFe: C, 50.12; H, 2.98.
Found: C, 50.19; H, 2.96.
Rea ction of [η-C5H5(CO)2RetCC6H5]BBr 4 (2) w ith 3 To
Give 8, [η-C5H 5-R e(CO)3] (12), a n d [R eF e{µ-C(SeC6H 5)-
C6H5}(CO)5(η-C5H5)] (13). Similar to the procedures used in
the reaction of 1 with 3, compound 2 (0.70 g, 0.963 mmol) was
treated with 3 prepared (in situ) by the reaction of Fe3(CO)12
(0.540 g, 1.07 mmol) with 0.12 mL (1.13 mmol) of C6H5SeH
and 0.18 mL (1.22 mmol) of Et3N at -100 to -50 °C for 7-8
h. Further treatment of the resulting mixture as in the reaction
of 1 with 3 afforded 0.014 g (4%, based on 2) of gray crystals
of 12,19 0.125 g (22%, based on 2) of red crystals of 8, and 0.470
g (70%, based on 2) of blackish green crystals of 13. 8 was
identified by its melting point and IR and 1H NMR spectra.
12 is a known compound which was identified by comparison
of its mp and IR and 1H NMR spectra with those of an
authentic sample. 13: mp 112 °C dec; IR (CH2Cl2) ν(CO) 2040
CH3CH2), 1.48 (m, 6H, CH3CH2); MS m/e 498 (M+), 442 [M+
-
2CO], 414 [M+ - 3CO], 386 [M+ - 4CO], 358 [M+ - 5CO],
330 [M+ - 6CO]. 17: mp 106-108 °C dec; IR (CH2Cl2) ν(CO)
2038 (vs), 1971 (s), 1936 (vs, br), 1881 (m) cm-1; 1H NMR (CD3-
COCD3) δ 7.65 (d, 2H, C6H5), 7.42 (t, 2H, C6H5), 7.25 (t, 1H,
C6H5), 4.62 (s, 5H, C5H5), 1.89 (q, 2H, CH3CH2), 1.17 (t, 3H,
CH3CH2); MS m/e 514 [M+], 458 [M+ - 2CO], 430 [M+ - 3CO],
402 [M+ - 4CO]. Anal. Calcd for C19H15O5SeMnFe: C, 44.48;
H, 2.95. Found: C, 44.28; H, 2.97.
Reaction of 2 with 5 To Give 15 an d [ReFe{µ-C(SeC2H5)-
C6H5}(CO)5(η-C5H5)] (18). As used in the reaction of 1 with
5, 2 (0.65 g, 0.90 mmol) was treated with 5 prepared (in situ)
by the reaction of 0.085 g (1.07 mmol) of selenium powder,
1.08 mmol of C2H5MgBr, and 0.537 g (1.06 mmol) of Fe3(CO)12
at -100 to -50 °C for 7 h. Further treatment as in reaction of
1 with 5 yielded 0.080 g (18%, based on 2) of red viscous oil of
15 and 0.420 g (73%, based on 2) of blackish red crystals of
18. 15 was identified by its melting point and IR, 1H NMR,
and mass spectra. 18: mp 114-116 °C dec; IR (CH2Cl2) ν(CO)
2036 (vs), 1967 (s), 1939 (s, br), 1879 (m) cm-1; 1H NMR (CD3-
COCD3) δ 7.54 (d, 2H, C6H5), 7.40 (t, 2H, C6H5), 7.36 (t, 1H,
C6H5), 5.25 (s, 5H, C5H5), 1.85 (q, 2H, CH3CH2), 1.20 (t, 3H,
CH3CH2); MS m/e 644 [M+], 616 [M+ - CO], 588 [M+ - 2CO],
560 [M+ - 3CO], 532 [M+ - 4CO], 504 [M+ - 5CO]. Anal.
Calcd for C19H15O5SeReFe: C, 35.42; H, 2.35. Found: C, 35.52;
H, 2.33.
1
(vs), 1974 (s), 1940 (s, br), 1882 (m), 1788 (m) cm-1; H NMR
(CD3COCD3) δ 7.67-7.05 (m, 10H, C6H5), 5.26 (s, 5H, C5H5);
MS m/e 694 [M+], 666 [M+ - CO], 638 [M+ - 2CO], 610
[M+ - 3CO], 582 [M+ - 4CO], 554 [M+ - 5CO],158 [C6H5-
SeH+]. Anal. Calcd for C23H15O5SeReFe: C, 39.90; H, 2.18.
Found: C, 40.05; H, 2.33.
Rea ction of 2 w ith [MgBr ][F e2(µ-CO)(µ-SeC6H4CH3-p)-
(CO)6] (4) To Give 9, 12, a n d [ReF e{µ-C(SeC6H4CH3-p)-
C6H5}(CO)5(η-C5H5)] (14). A Schlenk flask was charged with
0.079 g (1.00 mmol) of selenium powder, 20 mL of THF, and
1.01 mmol of Grignard reagent p-CH3C6H4MgBr in THF. The
mixture was stirred at room temperature for 20 min, and at
this time the selenium powder completely disappeared to give
a colorless solution. To this solution was added 0.500 g (0.991
mmol) of Fe3(CO)12, and the mixture was stirred at room
temperature for 30 min, resulting in formation of a brown-
red solution of the salt [MgBr][Fe2(µ-CO)(µ-SeC6H4CH3-p)-
(CO)6] (4),11b,16 which was cooled to -100 °C and then poured
rapidly onto 0.65 g (0.89 mmol) of freshly prepared 2 previously
cooled to -100 °C with vigorous stirring. Immediately the
brown-red solution turned dark brown. The reaction mixture
was slowly warmed to -80 °C and then stirred at -80 to -50
°C for 6 h. Further treatment of the resulting mixture as in
the reaction of 1 with 3 afforded 0.014 g (5%, based on 2) of
gray crystals of 12, 0.055 g (10%, based on 2) of red crystals
of 9, and 0.51 g (82%, based on 2) of deep purple-red crystals
of 14. Products 9 and 12 were identified by their mp and IR
R ea ct ion of 2 w it h [MgBr ][F e2(µ-CO)(µ-SeC4H9-n )-
(CO)6] (6) To Give [Fe2(µ-SeC4H9-n )2(CO)6] (16) an d [ReFe-
{µ-C(SeC4H9-n )C6H5}(CO)5(η-C5H5)] (19). In a manner simi-
lar to the procedure for the reaction of 1 with 5, 2 (0.70 g,
0.963 mmol) was treated with [MgBr][Fe2(µ-CO)(µ-SeC4H9-n)-
(CO)6] (6)16 prepared (in situ) by the reaction of 0.089 g (1.13
mmol) of selenium powder, 1.13 mmol of n-C4H9MgBr, and
0.562 g (1.12 mmol) of Fe3(CO)12 at -100 to -50 °C for 7 h.
Further treatment of the resulting mixture as in the reaction
of 1 with 3 afforded 0.085 g (16%, based on 2) of red viscous
oil of 16 and 0.390 g (60%, based on 2) of purple-red crystalline
19. 16: IR (CH2Cl2) ν(CO) 2060 (s), 2045 (m), 2026 (vs), 1982
1
(vs, br), 1935 (m) cm-1; H NMR (CD3COCD3) δ 2.77 (m, 4H,
(CH2)3CH3), 1.71 (m, 4H, (CH2)3CH3), 1.47 (m, 4H, (CH2)3CH3),
1
and H NMR spectra. 14: mp 82-83 °C dec; IR (CH2Cl2) ν(CO)
0.94 (m, 6H, (CH2)3CH3); MS m/e 552 (M+), 524 [M+ - CO],
2076 (vs), 2047 (vs), 2013 (vs),1987 (s), 1864 (s), 1827 (w) cm-1
;
496 [M+ - 2CO], 468 [M+ - 3CO] 440 [M+ - 4CO], 412 [M+
-
1H NMR (CD3COCD3) δ 7.65-6.96 (m, 9H, C6H5 + C6H4CH3),
5CO], 384 [M+ - 6CO]. Anal. Calcd for C14H18O6Se2Fe2: C,
30.47; H, 3.29. Found: C, 30.59; H, 3.23. 19: mp 56-57 °C
dec; IR (CH2Cl2) ν(CO) 2037 (vs), 1966 (s), 1942 (s, br), 1878
5.29 (s, 5H, C5H5), 2.17 (s, 3H, C6H4CH3); MS m/e 706 [M+],
678 [M+ - CO], 650 [M+ - 2CO], 622 [M+ - 3CO], 594 [M+
-
4CO], 566 [M+ - 5CO], 186 [CH3C6H4SeH+]. Anal. Calcd for
1
(m) cm-1; H NMR (CD3COCD3) δ 7.42 (d, 2H, C6H5), 7.35 (t,
C
24H17O5SeReFe: C, 40.81; H, 2.43. Found: C, 40.74; H, 2.55.
(20) Rosenbuch, P.; Welcman, N. J . Chem. Soc., Dalton Trans. 1972,
1963.
(19) Abad, I. Nauk. SSSR Ser. Khim. 1974 (3), 710.

RSe-Bridged Dimetal Bridging Carbene Complexes
Organometallics, Vol. 20, No. 11, 2001 2229
Ta ble 1. Cr ysta l Da ta a n d Exp er im en ta l Deta ils for Com p lexes 9, 10, 13, 18, a n d 20
9
10
13
18
20
formula
fw
C
20H14O6Se2Fe2
C23H15O5SeMnFe
561.11
C23H15O5SeReFe
692.38
C19H15O5SeReFe
644.34
C20H11O8MnFe2
545.93
619.94
space group
a (Å)
b (Å)
P21/c (No. 14)
12.395(2)
17.293(4)
22.150(3)
P1h (No. 2)
9.632(5)
16.174(5)
7.273(3)
96.69(3)
93.24(4)
102.63(3)
1094.2(8)
2
1.703
556.00
29.34
Mo KR
P1h (No. 2)
10.929(4)
11.639(2)
9.017(2)
97.95(2)
91.18(2)
75.68(2)
1100.6(5)
2
1.508
656.00
78.41
Mo KR
P1h (No. 2)
9.137(2)
13.923(2)
8.734(2)
103.06(2)
113.04(1)
80.22(2)
991.9(3)
2
2.157
608.00
86.91
Mo KR
P21/c (No. 14)
8.169(3)
9.038(2)
c (Å)
27.434(9)
R (deg)
â (deg)
γ (deg)
V (Å3 )
104.19(1)
91.35(3)
4603(1)
8
1.789
2416.00
44.54
Mo KR
(λ ) 0.71069 Å)
Rigaku AFC7R
20
2025(1)
4
1.791
1088.00
20.72
Mo KR
(λ ) 0.71069 Å)
Rigaku AFC7R
20
Z
dcalcd (g /cm3)
F(000)
µ(Mo KR) (cm-1
)
radiation (monochromated
in incident beam)
diffractometer
(λ ) 0.71069 Å)
Rigaku AFC7R
20
(λ ) 0.71069 Å)
Rigaku AFC7R
20
(λ ) 0.71069 Å)
Rigaku AFC7R
20
temperature (°C)
orientation reflections: no.;
range (2θ) (deg)
20; 13.7-21.5
19; 12.7-22.5
19; 18.5-21.4
19; 18.3-25.6
15; 11.1-18.1
scan method
ω-2θ
ω-2θ
5-50
3861
1467
280
0.7493-1.0786
0.065
0.065
1.59
0.00
0.59
ω-2θ
5-50
3427
3028
280
0.9010-1.0642
0.028
0.036
1.55
0.00
1.03
ω-2θ
ω-2θ
5-51
3775
1449
280
0.8169-1.0706
0.059
0.065
1.53
0.01
0.54
data coll. range, 2θ (deg)
no. of unique data,
total with I >2.50σ(I)
no. of params refined
corr factors, max., min.
Ra
5-50
5-50
6356
2871
3645 (I >2.00σ(I))
541
0.8068-1.0000
0.040
0.041
1.17
0.00
0.44
2586 (I >3.00σ(I))
245
0.7418-1.2593
0.038
0.049
2.15
0.03
1.18
b
Rw
quality-of-fit indicatorc
largest shift/esd. final cycle
max. peak, e-/Å3
min. peak, e-/Å3
-0.39
-0.73
-1.03
-1.43
-0.60
a
b
2
R ) ∑||Fo| - |Fc||/∑|Fo|. Rw ) [∑w(|Fo| - |Fc|)2/∑w|Fo| ]1/2; w ) 1/σ2(|Fo|). c Quality-of-fit ) [∑w(|Fo| - |Fc|)2/(Nobs - Nparameters)]1/2
.
2H, C6H5), 7.12 (d, 1H, C6H5), 5.27 (s, 5H, C5H5), 0.86 (m, 1H,
(CH2)3CH3), 1.70 (m, 1H, (CH2)3CH3), 1.51 (m, 2H, (CH2)3CH3),
1.19 (q, 2H, (CH2)3CH3), 0.74 (t, 3H, (CH2)3CH3); MS m/e 672
[M+], 618 [M+ - 2CO], 590 [M+ - 3CO], 534 [M+ - 5CO]. Anal.
Calcd for C21H19O5SeReFe: C, 37.51; H, 2.85. Found: C, 37.68;
H, 2.81.
radiation with an ω-2θ scan mode within the range 5° e
2θ e 50°.
The structures of 9, 10, 13, 18, and 20 were solved by the
direct methods and expanded using Fourier techniques. For
all five complexes, the non-hydrogen atoms were refined
anisotropically, and the hydrogen atoms were included but not
refined. The final cycle of full-matrix least-squares refinement
was respectively based on 3645, 1467, 3208, 2586, and 1449
observed reflections and 541, 280, 280, 245, and 280 variable
parameters and converged with unweighted and weighted
agreement factors of R ) 0.040 and Rw ) 0.041 for 9, R ) 0.065
and Rw ) 0.065 for 10, R ) 0.028 and Rw ) 0.036 for 13, R )
0.038 and Rw ) 0.049 for 18, and R ) 0.059 and Rw ) 0.065
for 20, respectively. All the calculations were performed using
the teXsan crystallographic software package of Molecular
Structure Corporation.
Rea ction of 1 w ith 6 To Give 16 a n d [Mn F e2(µ-H)(µ-
CO)2(µ3-CC6H5)(CO)6(η-C5H5)] (20). The reaction of 1 (0.880
g, 1.48 mmol) with 6 prepared (in situ) by the reaction of 0.130
g (1.65 mmol) of selenium powder, 1.65 mmol of n-C4H9MgBr,
and 0.822 g (1.63 mmol) of Fe3(CO)12 was as in the reaction of
1 with 5 at -100 to -50 °C for 7 h, during which time the
dark brown solution turned dark purple-red. Further treat-
ment in a manner similar to that in the reaction of 2 with 6
yielded 0.150 g (18%, based on 1) of red viscous oil of 16 and
0.370 g (47%, based on 1) of blackish red crystalline 20.
Product 16 was identified by its mp and IR, 1H NMR, and mass
spectra. 20: mp 140 °C dec; IR (CH2Cl2) ν(CO) 2076 (s), 2039
The details of the crystallographic data and the procedures
used for data collection and reduction information for 9, 10,
13, 18, and 20 are given in Table 1. The selected bond lengths
and angles are listed in Tables 2 and 3, respectively. The
(vs), 2012 (w),1975 (vs), 1942 (s, br), 1879 (s), 1870 (w) cm-1
;
1H NMR (CD3COCD3) δ 8.02 (m, 2H, C6H5), 7.98 (m, 2H, C6H5),
7.53 (m, 1H, C6H5), 4.79 (s, 5H, C5H5), -23.84 (s, 1H, µ-H);
MS m/e 546 [M+], 545 [M+ - H], 517 [M+ - H - CO], 489
[M+ - H - 2CO], 433 [M+ - H - 5CO], 405 [M+ - H - 6CO],
349 [M+ - H - 8CO]. Anal. Calcd for C20H11O8MnFe2: C,
44.00; H, 2.03. Found: C, 43.83; H, 2.40.
atomic coordinates and
Biso/Beq, anisotropic displacement
parameters, complete bond lengths and angles, least-squares
planes for 9, 10, 13, 18, and 20, and the molecular structures
of 9 and 13 are given in the Supporting Information. The
molecular structures of 10, 18, and 20 are given in Figures 1,
2, and 3, respectively.
X-r a y Cr ysta l Str u ctu r e Deter m in a tion s of Com p lexes
9, 10, 13, 18, a n d 20. The single crystals of complexes 9, 10,
13, 18, and 20 suitable for X-ray diffraction study were
obtained by recrystallization from petroleum ether or petro-
leum ether/CH2Cl2 at -80 °C. Single crystals were mounted
on a glass fiber and sealed with epoxy glue. The X-ray
diffraction intensity data for 6356, 3861, 3427, 2871, and 3775
independent reflections, of which 3645 with I > 2.00σ(I) for 9,
1467, 3028, and 1449 with I > 2.50σ(I) for 10, 13, and 20, and
2586 with I > 3.00σ(I) for 18 were observable, were collected
with a Rigaku AFC7R diffractometer at 20 °C using Mo KR
Resu lts a n d Discu ssion
The complex [η-C5H5(CO)2MntCC6H5]BBr4 (1) was
treated, in separate experiments, with an equimolar
quantity of freshly prepared (in situ) [Et3NH][Fe2(µ-
CO)(µ-SeC6H5)(CO)6] (3) and [Et3NH][Fe2(µ-SeC6H4CH3-
p)(CO)6] (4) in THF at low temperature (-100 to -50
°C) for 7-8 h. After vacuum removal of the solvent, the
residue was chromatographed on an alumina column
at low temperature, and the crude products were

2230 Organometallics, Vol. 20, No. 11, 2001
Ta ble 2. Selected Bon d Len gth s (Å)a a n d An gles (d eg)a for Com p lexes 10, 13, a n d 18
Wang et al.
10 M ) Mn
13 M ) Re
18 M ) Re
10 M ) Mn
13 M ) Re
18 M ) Re
M-Fe
2.697(3)
2.00(2)
1.86(2)
2.398(3)
1.99(2)
1.92(2)
1.54(2)
47.7(5)
43.4(4)
88.9(7)
76.8(1)
105.5(7)
48.9(4)
2.7731(9)
2.118(6)
1.918(6)
2.397(1)
1.965(6)
1.938(7)
1.488(8)
49.7(2)
43.7(2)
86.6(2)
79.96(4)
109.4(3)
51.0(2)
2.782(1)
2.130(9)
1.927(9)
2.395(2)
1.964(8)
1.97(1)
1.46(1)
49.9(3)
43.7(2)
86.4(4)
M-C(1)
1.77(2)
1.79(2)
1.75(2)
1.77(2)
1.78(2)
2.144
1.874(8)
1.877(9)
1.761(8)
1.818(7)
1.791(8)
2.302
1.883(9)
1.90(1)
1.77(1)
1.77(1)
1.84(1)
2.286
M-C(6)
M-C(2)
Fe-C(6)
Fe-C(3)
Fe-C(4)
Fe-C(5)
M-C(Cp) (av)
Fe-Se
Se-C(6)
Se-C(18)
C(6)-C(7)
M-Fe-C(6)
Fe-M-C(6)
M-C(6)-Fe
M-Fe-Se
M-C(6)-Se
Fe-Se-C(6)
Se-Fe-C(6)
Fe-C(6)-Se
M-C(6)-C(7)
Fe-C(6)-C(7)
C(6)-Se-C(18)
Fe-Se-C(18)
54.1(5)
77.0(6)
122(1)
137(1)
112.8(7)
104.7(5)
52.8(2)
76.3(2)
120.4(4)
136.9(4)
108.5(3)
103.9(2)
52.7(2)
76.0(3)
122.7(6)
135.3(7)
105.5(4)
106.3(3)
80.48(4)
110.1(4)
51.3(3)
a
Estimated standard deviations in the least significant figure are given in parentheses.
Ta ble 3. Selected Bon d Len gth s (Å)a a n d An gles
(d eg)a for Com p lex 20
Mn-Fe(1)
Mn-Fe(2)
Fe(1)-Fe(2)
Mn-C(6)
Fe(1)-C(6)
Fe(2)-C(6)
C(6)-C(7)
Mn-C(1)
Fe(1)-C(1)
Mn-C(2)
2.606(3)
2.612(3)
2.640(5)
2.00(1)
1.94(1)
1.95(1)
1.47(2)
1.84(2)
2.37(2)
1.80(2)
Fe(2)-C(2)
2.33(2)
1.80(1)
1.78(2)
1.81(2)
1.76(2)
1.78(2)
1.85(2)
2.11
Fe(1)-C(3)
Fe(1)-C(4)
Fe(1)-C(5)
Fe(2)-C(18)
Fe(2)-C(19)
Fe(2)-C(20)
Mn-C(Cp) (avg.)
Fe(1)-H(11)
Fe(2)-H(11)
1.74
1.80
Fe(1)-Mn-Fe(2)
Mn-Fe(1)-Fe(2)
Mn-Fe(2)-Fe(1)
Mn-C(6)-Fe(1)
Mn-C(6)-Fe(2)
Fe(1)-C(6)-Fe(2)
Fe(1)-Mn-C(6)
Fe(2)-Mn-C(6)
Mn-Fe(1)-C(6)
Fe(2)-Fe(1)-C(6)
60.77(8)
Mn-Fe(2)-C(6)
Fe(1)-Fe(2)-C(6)
Mn-C(1)-Fe(1)
Mn-C(2)-Fe(2)
Mn-C(6)-C(7)
Fe(1)-C(6)-C(7)
Fe(2)-C(6)-C(7)
Mn-C(1)-O(1)
Mn-C(2)-O(2)
49.4(4)
47.0(4)
75.4(6)
77.2(6)
130(1)
129(1)
128(1)
158(1)
158(1)
59.74(8)
59.49(8)
83.0(5)
82.7(5)
85.5(5)
47.5(4)
47.9(4)
49.6(4)
47.6(4)
F igu r e 1. Molecular structure of 10, showing the atom-
numbering scheme with 40% thermal ellipsoids.
a
Estimated standard deviations in the least significant figure
are given in parentheses.
ionic compounds 3 and 4 under the same conditions to
afford the Re-Fe dimetal bridging carbene complexes
[ReFe{µ-C(SeC6H5)C6H5}(CO)5(η-C5H5)] (13) and [ReFe-
{µ-C(SeC6H4CH3-p)C6H5}(CO)5(η-C5H5)] (14) in 70% and
82% yield, respectively, in addition to [η-C5H5Re(CO)3]
(12) and 8 or 9 (eq 2).
Compounds 10, 11, 13, and 14 are readily soluble in
polar organic solvents but only sparingly soluble in
nonpolar solvents. They are very sensitive to air and
temperature in solution but relatively stable as the
solid. On the basis of elemental analyses, spectroscopic
evidence, and X-ray crystallography, products 10, 11,
13, and 14 are formulated as heteronuclear dimetal
bridging carbene complexes possessing a SeR ligand
bridged to the Fe atom and carbene carbon, similar to
the complexes [MFe{µ-C(SR)C6H5}(CO)5(η-C5H5)] shown
in eq 1. The X-ray diffraction studies for complexes 10
and 13 were carried out in order to firmly establish their
structures.
recrystallized from petroleum ether/CH2Cl2 solution at
-80 °C to give yellow crystals of [η-C5H5Mn(CO)3] (7),
red selenolato-bridged iron carbonyl compounds [Fe2-
(µ-SeC6H5)2(CO)6] (8) and [Fe2(µ-SeC6H4CH3-p)2(CO)6]
(9), and blackish green Mn-Fe dimetal bridging carbene
complexes [MnFe{µ-C(SeC6H5)C6H5}(CO)5(η-C5H5)] (10)
(from 3) and [MnFe{µ-C(SeC6H4CH3-p)C6H5}(CO)5(η-
C5H5)] (11) (from 4) (eq 2) in 5-6%, 24-25%, and 63-
66% yields, respectively, among which 717 and 818 are
known compounds.
The molecular structure of complex 10 (Figure 1)
confirmed that the SeR ligand bridges the carbene
carbon (C(6)) and the Fe atom through the Se atom and
provides two electrons for Fe to satisfy the 18-electron
configuration. The Mn-Fe distance of 2.697(3) Å is
approximately the same as that found in analogous
bridging carbene complexes [MnFe{µ-C(SC4H9-n)C6H5}-
(CO)5(η-C5H5)] (2.705(4) Å),9 [MnFe{µ-C(SC6H5)C6H5}-
(CO)5(η-C5H5)] (2.704(2) Å),9 and [MnFe{µ-C(COEt)-
C6H5}(CO)5(η-C5H5)] (2.6929(8) Å),7b but obviously longer
Like 1, the cationic carbyne complex of rhenium,
[η-C5H5(CO)2RetCC6H5]BBr4 (2), also reacts with an-

RSe-Bridged Dimetal Bridging Carbene Complexes
Organometallics, Vol. 20, No. 11, 2001 2231
than that in the bridging carbyne complex [(η-C5H5)-
(CO)Fe(µ-CO)(µ-COEt)Mn(CO)(η-MeC5H4)] (2.572(1) Å).21
The µ-C-Mn distance of 2.00(2) Å is slightly shorter
than that in the analogous complex [MnFe{µ-C(SC6H5)-
C6H5}(CO)5(η-C5H5)] (2.057(9) Å).9 The µ-C-Fe bond
length of 1.86(2) Å is not only shorter than that in the
bridging carbene complexes [MnFe{µ-C(COEt)C6H5}-
(CO)5(η-C5H5)] (2.020(4) Å)7b and [Fe2{µ-C(OC2H5)C6H4-
CF3-p}(CO)2(C8H8)] (average 2.037 Å)22 but also shorter
than that in analogous complexes [MnFe{µ-C(SC4H9-
n)C6H5}(CO)5(η-C5H5)] (1.94(1) Å)9 and [MnFe{µ-C(S-
C6H5)C6H5}(CO)5(η-C5H5)] (1.897(9) Å)9 and is compa-
rable to that in the bridging carbyne complex [MnFe(µ-
CC6H5)(CO)4(NO)(η-C5H5)] (1.853(3) Å).8f This might be
caused by bridging of the SeR group leading to the ring
shrinkage. The Se-Fe bond length of 2.398(3) Å is
somewhat longer than that found (average 2.363 Å) in
[Fe2(µ-Se)2(CO)6].23 The C(6)-Se distance (1.99(2) Å)
and Se-Fe distance in 10 are both obviously longer than
the C(6)-S distance (1.799(9) Å) and S-Fe distance
(2.279(3) Å), respectively, in [MnFe{µ-C(SC6H5)C6H5}-
(CO)5(η-C5H5)].9
The structure of complex 13 (Supporting Information)
resembles that of 10. Both structures have many
common features. The Re-Fe bond distance (2.7731(9)
Å) in 13 is very close to that in analogous complexes
[ReFe{µ-C(SC4H9-n)C6H5}(CO)5(η-C5H5)] (2.784(2) Å)9
and [ReFe{µ-C(H)C6H5}(CO)6(η-C5H5)] (2.7581(8) Å)7a
but is slightly longer than that found in [ReFe(µ-CC6H5)-
(µ-CO)(CO)3(η-C5H5)(COC2H-B10H10)] (2.682(6) Å).24
The µ-C-Re distance (2.118(6) Å) is the same within
experimental error as that in [ReFe{µ-C(SC4H9-n)-
C6H5}(CO)5(η-C5H5)] (2.128(10) Å)9 and [ReFe{µ-C(H)-
C6H5}(CO)6(η-C5H5)] (2.120(5) Å),7a while the µ-C-Fe
distance of 1.918(6) Å is somewhat shorter than that in
[ReFe{µ-C(SC4H9-n)C6H5}(CO)5(η-C5H5)] (1.951(1) Å)9
and [ReFe{µ-C(H)C6H5}(CO)6(η-C5H5)] (2.097(5) Å).7a
The Se-Fe (2.397(1) Å) and Se-C(6) (1.965(6) Å) bond
lengths are close to those of 10.
single signal for the R group. However, the 1H NMR
spectrum of 9 showed the two singlets of the methyl
proton signals of the p-tolyl group respectively at 2.28
and 2.06 ppm, while the benzene ring proton showed
two sets of A2B2 resonances at ca. 7.36-7.07 ppm.
Hence, we consider that complex 9 adopts the B con-
figuration, where the two R (p-CH3C6H4) groups lie in
trans position and have different chemical environ-
ments.
Althuogh several bis(µ-SeR)hexacarbonyldiiron com-
pounds have been synthesized,11a,18,20,25 no X-ray struc-
ture of such compounds is known. To firmly confirm
their configuration and examine their structural fea-
tures, a single-crystal X-ray diffraction study was car-
ried out on complex 9. The structural data and the
molecular structure of 9 are given in the Supporting
Information. The results of the X-ray diffraction of 9
confirmed its B configuration. Complex 9 appears to be
the first example of a species with Fe-Fe and Fe-Se-
(R) bonds studied by X-ray crystallography.
To explore the effect of different substituents on the
Se atom on the reactivity of the reactive salts and
reaction products, [MgBr][Fe2(µ-CO)(µ-SeC2H5)(CO)6]
(5), where the substituent on Se is an ethyl group, and
the n-butyl analogue were used in the reaction with 1
and 2 under the same conditions. The known bis(µ-
SeC2H5)hexacarbonyldiiron compound 15 and bridging
carbene complexes [MnFe{µ-C(SeC2H5)C6H5}(CO)5(η-
C5H5)] (17) and [ReFe{µ-C(SeC2H5)C6H5}(CO)5(η-C5H5)]
(18) were formed in 18-19% and 72-73% yield, respec-
tively, in the case of [MgBr][Fe2(µ-CO)(µ-SeC2H5)(CO)6]
(eq 3).
Complexes 8 and 9 are known bis[µ-(areneselenolato)]-
hexacarbonyldiiron compounds, reported previously by
Schermer18 and Song,11a respectively. It is interesting
to note that there are three possible steric configura-
tions, A, B, and C, in the bis(µ-SeR)hexacarbonyldiiron
compounds. The configuration A is unfavorable in steric
Analogous products [Fe2(µ-SeC4H9-n)2(CO)6] (16) and
[ReFe{µ-C(SeC4H9-n)C6H5}(CO)5(η-C5H5)] (19) in 16%
and 60% yield, respectively, were obtained in the
reaction of [MgBr][Fe2(µ-CO)(µ-SeC4H9-n)(CO)6] (6) with
2 (eq 4).
The structures of complexes 17-19 were supported
by their elemental analyses and IR, 1H NMR, and mass
spectra, among which the structure of complex 18 has
been further confirmed by its X-ray crystallography.
effect because of the steric repelling action of the two
neighboring R groups. For configuration C, the two R
groups lie in cis position and have the same chemical
1
environment; thus, its H NMR spectrum should be a
The molecular structure of 18 shown in Figure 2
resembles that of 13, except that the substituent on the
Se atom is an ethyl group instead of a phenyl group.
The Re-Fe distance (2.782(1) Å) is nearly the same as
that in 13. The µ-C-Re distance of 2.130(9) Å and the
(21) Fong, R. H.; Lin, C.-H.; Idmouaz, H.; Hersh, W. H. Organome-
tallics 1993, 12, 503.
(22) Chen, J .-B.; Li, D.-S.; Yu, Y.; J in, Z.-S.; Zhou, Q.-L.; Wei, G.-C.
Organometallics 1993, 12, 3885.
(23) Campana, C. F.; Yip-Kwai Lo, F.; Dahl, L. F. Inorg. Chem. 1979,
18, 3060.
(24) Zhu, B.; Yu, Y.; Chen, J .-B.; Wu, Q.-J .; Liu, Q.-T. Organome-
tallics 1995, 14, 3963.
(25) Rosenbuch, P.; Welcman, N. J . Chem. Soc., Dalton Trans. 1972,
1963.

2232 Organometallics, Vol. 20, No. 11, 2001
Wang et al.
F igu r e 2. Molecular structure of 18, showing the atom-
numbering scheme with 40% thermal ellipsoids.
F igu r e 3. Molecular structure of 20, showing the atom-
numbering scheme. Thermal ellipsoids are shown at 45%
probability.
plex, [MnFe2(µ-H)(µ-CO)2(µ3-CC6H5)(CO)6(η-C5H5)] (20),
in reasonable yield, in addition to product 16 (eq 5).
µ-C-Fe distance of 1.927(9) Å are both slightly longer
than those found in 13, while the Se-C(6) distance
(1.963(8) Å) and Se-Fe distance (2.395(2) Å) are both
the same within experimental error as those in 13.
The reaction pathways to complexes 10, 11, 13, 14,
and 17-19 are not clear. Presumably, their formation
occurred via an [Fe(CO)3(SeR)]- anion derived from
dissociation of the [X][Fe2(µ-CO)(µ-SeR)(CO)6] salt, a
process involving the breaking of Fe-Fe and Fe-Se
bonds. The anion might then attack the carbyne carbon
of 1 or 2 with bonding of the Fe atom to the Mn or Re
atom and the Se atom to the carbyne carbon to construct
an RSe-bridged dimetallacyclopropane ring. Two [Fe-
(CO)3(SeR)] fragments could form a selenolato-bridged
iron carbonyl compound [Fe2(µ-SeR)2(CO)6] by their
dimerization. To our knowledge, no such Fe-Se and
Fe-Fe bond cleavage in the reactions of the [Fe2(µ-CO)-
(µ-SeR)(CO)6]- anions has been reported up to now.
However, unlike [Et3NH][Fe2(µ-CO)(µ-SPh)(CO)6], the
[Et3NH][Fe2(µ-CO)(µ-SePh)(CO)6] salt did not undergo
cleavage to generate a PhSe- species, and formation of
a phenylselenocarbene complex, an analogue of the
phenylthiocarbene complex [η-C5H5(CO)2MdC(SPh)-
C6H5] (M ) Mn or Re),9 was not observed in the reaction
of [Et3NH][Fe2(µ-CO)(µ-SePh)(CO)6] with 1 or 2.
Complex 20 is formulated as a µ-H-bridged hetero-
nuclear trimetal bridging carbyne complex whose struc-
1
ture has been established by its H NMR spectrum and
X-ray diffraction study. The existence of the bridging
H atom in 20 was initially revealed by its 1H NMR
spectrum, which showed a high-field resonance at δ
-23.84, characteristic for an Fe-H-Fe species.
The structure of 20 has been further confirmed by its
X-ray crystallography; its molecular structure is shown
in Figure 3. In 20, the triangular MnFeFe arrangement
with a capping µ3-CC6H5 ligand is confirmed. The three
metal atoms construct an approximate isosceles triangle
(Mn-Fe(1) ) 2.606(3) Å, Mn-Fe(2) ) 2.612 (3) Å, and
Fe(1)-Fe(2) ) 2.640(5) Å). While an analogous bridging
carbyne complex with a trimetalatetrahedrane CMn-
FeFe core has been synthesized by reaction26 of [Mn3-
(µ-H)3(CO)12] with trans-[Fe2(µ-CdCH2)(µ-CO)(CO)2(η-
C5H5)2], compound 20 appears to be the first example
Surprisingly, the reaction of 1 with [MgBr][Fe2(µ-CO)-
(µ-SeC4H9-n)(CO)6] (6) under the same conditions gave
no analogous dimetal bridging carbene complex but
rather an unexpected trimetal bridging carbyne com-
(26) Brun, P.; Dawkins, G. M.; Green, M.; Mills, R. M.; Salauen,
J .-Y.; Stone, F. G. A.; Woodward, P. J . Chem. Soc., Dalton Trans. 1983,
1357.

RSe-Bridged Dimetal Bridging Carbene Complexes
Organometallics, Vol. 20, No. 11, 2001 2233
of a species with Mn-Fe, Mn-Fe, and Fe-Fe bonds
studied by X-ray crystallography. The Mn-Fe bond
lengths (average 2.609 Å) in 20 are slightly longer than
that in the analogous complex [MnFeCo(µ3-CC6H5)(µ-
CO)(CO)7(η-C5H5)] (2.570(2) Å).8e The Fe(1)-Fe(2) bond
length is somewhat longer than that of the similar com-
plex [WFe2(µ3-CC6H4Me-4)(µ-CO)(CO)8(η-C5H5)] (2.538-
(2) Å).4d The µ-C(6)-Mn, µ-C(6)-Fe(1), and µ-C(6)-Fe(2)
distances are 2.00(1), 1.94(1), and 1.95(1) Å, respec-
tively, of which the µ-C-Mn bond length is closely
related to that found in complex [MnFeCo(µ3-CC6H5)-
(µ-CO)(CO)7(η-C5H5)] (1.94(1) Å),8e while the µ-C-Fe
bond length (average 1.945 Å) is nearly the same as that
in [MnFeCo(µ3-CC6H5)(µ-CO)(CO)7(η-C5H5)] (1.91(1) Å)8e
but slightly shorter than that in [WFe2(µ3-CC6H4Me-
4)(µ-CO)(CO)8(η-C5H5)] (average 2.003 Å).4d
glassware. To our knowledge, no such Fe-C and Fe-
Se bond cleavage (namely, the bridging CO and SeR
groups were simultaneously replaced by another bridg-
ing ligand in the reaction of the [X][Fe2(µ-CO)(µ-SeR)-
(CO)6] salt) has been reported.
A series of trimetal bridging carbyne complexes
have been synthesized by Stone et al. and by us by reac-
tions4c,d,8e,f,24,28 of alkylidyne complexes with low-valent
metal species. However, complex 20, as a trimetal
bridging carbyne complex, was synthesized by the
reaction of a transition metal cationic carbyne complex
with a carbonylmetal anion for the first time. Such
reaction of a cationic carbyne complex with a [X][Fe2-
(µ-CO)(µ-SeR)(CO)6] salt producing a trimetal bridging
carbyne complex is quite unusual.
In conclusion, the title reaction shows unusual reac-
tions between the diiron anions and the cationic carbyne
complexes of manganese and rhenium. The reaction
results indicate that the different diiron anions exert a
great influence on the reactivity of the cationic carbyne
complexes and reaction products and that the different
cationic carbyne complexes exhibit certain influences on
the resulting products. This offers a useful method for
the preparation of the heteroatom-bridged dimetal
bridging carbene and trimetal bridging carbyne com-
plexes.
In 20 the Fe(1) and Fe(2) atoms are bridged by a
hydrogen, the average Fe-H distance being 1.77 Å. The
two Fe atoms each carry three terminal CO groups, and
the Mn atom carries two CO groups, being semibridging
to the two Fe atoms, respectively (Mn-C(1)-O(1) ) 158-
(1)°, Fe(1)-C(1) ) 2.37(2) Å; Mn-C(2)-O(2) ) 158(1)°,
Fe(2)-C(2) ) 2.33(2) Å). Complex 20 is a 48 CVE
(cluster valence electron) complex, where the Mn and
Fe atoms formally have 19 and 17 electrons, respec-
tively, which probably accounts for the presence of the
semibridging carbonyl and bridging hydrogen. In 20, the
semibridging CO ligands reveal themselves in the IR
Ack n ow led gm en t. Financial support from the Na-
tional Natural Science Foundation of China and the
Science Foundation of the Chinese Academy of Sciences
is gratefully acknowledged.
spectrum with the two bands at 1879 and 1870 cm-1
,
respectively. The analogous 48-valence-electron struc-
ture was found in the complexes [MW2(µ3-C2R2)(CO)7-
(η-C5H5)2] (M ) Ru or Os)27 and [ReFeCo(µ3-CC6H5)-
(CO)8(η-C5H5)].8e
Su p p or tin g In for m a tion Ava ila ble: Tables of the posi-
tional parameters and Biso/Beq, H atom coordinates, anisotropic
displacement parameters, complete bond lengths and angles,
and least-squares planes for 9, 10, 13, 18, and 20 and
molecular structural figures for 9 (Figure 4) and 13 (Figure
5). This material is available free of charge via the Internet
at http://pubs.acs.org.
Complex 20 might be produced by loss of a µ-CO and
a µ-SeC4H9-n moiety from the [Fe2(µ-CO)(µ-SeC4H9-n)-
(CO)6]- anion involving the breaking of Fe-C (µ-CO)
and Fe-Se bonds or by cleavage of the formed carbene
intermediate [(η-C5H5)-MndC(C6H5){Fe2(µ-CO)(µ-SeC4-
H9-n)(CO)6}] to generate a [Fe2(CO)6H]- species, which
then becomes bonded to the carbyne or carbene carbon
through the two Fe atoms with bonding of the Mn atom
to the two Fe atoms to afford complex 20. The origin of
the H- in this reaction could be THF solvent or water,
which is a trace contaminant in the solvent THF or from
OM001035A
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P. J . Chem. Soc., Dalton Trans. 1982, 699. (b) Chetcuti, M. J .; Howard,
J . A. K.; Mills, R. M.; Stone, F. G. A.; Woodward, P. J . Chem. Soc.,
Dalton Trans. 1982, 1757. (c) Green, M.; Porter, S. J .; Stone, F. G. A.
J . Chem. Soc., Dalton Trans. 1983, 513. (d) Carriedo, G. A.; J effery, J .
C.; Stone, F. G. A. J . Chem. Soc., Dalton Trans. 1984, 1597. (e) J effery,
J . C.; Lewis, D. B.; Lewis, G. E.; Stone, F. G. A. J . Chem. Soc., Dalton
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