Synthesis of double and quadruple butterfly Fe/E cluster complexes via a new type of selenium-centered anions (μ-RE). See abstract

Article abstract of DOI:10.1021/om0102549

The [Et₃NH]⁺ or [MgBr]⁺ salts of anions [(μ-RE)(μ-CO)Fe₂(CO)₆]^- (1, E = S, Se, Te) reacted with (μ-Se₂)Fe₂(CO)₆ followed by treatment of the [Et₃NH]⁺ or [MgBr]⁺ salts of the intermediate selenium-centered anions (μ-RE)(μ-Se^-)[Fe₂(CO)₆]₂ (μ₄-Se) (3) with monohalide PhCH₂Br or MeI to give a series of double butterfly Fe/E cluster complexes (μ-RE)(μ-R¹Se)-[Fe₂(CO)₆]₂ (μ₄-Se) (4, RE = EtS, R¹ = PhCH₂; 5, t-BuS, PhCH₂; 6, p-MeC₆H₄Se, PhCH₂; 7 p-MeC₆H₄Se, Me; 8, p-MeC₆H₄Te, PhCH₂; 9, p-MeC₆H₄Te, Me). Similarly, reaction of the in situ prepared [Et₃NH]⁺ salt of the intermediate selenium-centered anion (μ-t-BuS)(μ-Se^-)-[Fe₂(CO)₆]₂ (μ₄-Se) with dihalide 1,2-(BrCH₂)₂C₆H₄ or 1,3-(BrCH₂)₂-5-MeC₆H₃ afforded quadruple butterfly Fe/E cluster {(μ-t-BuS){Fe₂(CO)₆]₂ (μ₄-Se)}₂ (μ-1-SeCH₂C₆H₄CH₂Se-2-μ (10) or double butterfly Fe/E cluster (μ-t-BuS)[(μ-1-SeCH₂-3-BrCH₂-5-MeC₆H ₃)[Fe₂(CO)₆]₂ (μ₄-Se) (11) and quadruple butterfly Fe/E cluster {(μ-t-BuS)[Fe₂(CO)₆]₂ (μ₄-Se)}₂(μ-1-SeCH₂-5- MeC₆H₃CH₂Se-3μ) (12), respectively. All the new products 4-11 have been characterized by elemental analysis, IR ¹H and ⁷⁷Se NMR spectroscopy, and for 4, 7, and 9 single-crystal X-ray diffraction techniques.

Full text of DOI:10.1021/om0102549

Organometallics 2001, 20, 3293-3298
3293
Syn th esis of Dou ble a n d Qu a d r u p le Bu tter fly F e/E
Clu ster Com p lexes via a New Typ e of Selen iu m -Cen ter ed
An ion s (µ-RE)(µ-Se-)[F e2(CO)6]2(µ4-Se) (E ) S, Se, Te)
Der ived fr om Novel Rea ction of [(µ-RE)(µ-CO)[F e2(CO)6]-
w ith (µ-Se2)F e2(CO)6. Cr ysta l Str u ctu r es of
µ4-Se-Con ta in in g Dou ble Clu ster s
(µ-EtS)(µ-P h CH2Se)[F e2(CO)6]2(µ4-Se),
(µ-p-MeC6H4Se)(µ-MeSe)[F e2(CO)6]2(µ4-Se), a n d
(µ-p-MeC6H4Te)(µ-MeSe)[F e2(CO)6]2(µ4-Se)
Li-Cheng Song,*,† J ing Yang,† Qing-Mei Hu,†,‡ and Qiang-J in Wu§
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai
University, Tianjin 300071, China, State Key Laboratory of Organometallic Chemistry,
Shanghai 200032, China, and State Key Laboratory of Structural Chemistry,
Fuzhou, 350002, China
Received March 27, 2001
The [Et3NH]+ or [MgBr]+ salts of anions [(µ-RE)(µ-CO)Fe2(CO)6]- (1, E ) S, Se, Te) reacted
with (µ-Se2)Fe2(CO)6 followed by treatment of the [Et3NH]+ or [MgBr]+ salts of the
intermediate selenium-centered anions (µ-RE)(µ-Se-)[Fe2(CO)6]2(µ4-Se) (3) with monohalide
PhCH2Br or MeI to give a series of double butterfly Fe/E cluster complexes (µ-RE)(µ-R1Se)-
[Fe2(CO)6]2(µ4-Se) (4, RE ) EtS, R1 ) PhCH2; 5, t-BuS, PhCH2; 6, p-MeC6H4Se, PhCH2; 7,
p-MeC6H4Se, Me; 8, p-MeC6H4Te, PhCH2; 9, p-MeC6H4Te, Me). Similarly, reaction of the in
situ prepared [Et3NH]+ salt of the intermediate selenium-centered anion (µ-t-BuS)(µ-Se-)-
[Fe2(CO)6]2(µ4-Se) with dihalide 1,2-(BrCH2)2C6H4 or 1,3-(BrCH2)2-5-MeC6H3 afforded qua-
druple butterfly Fe/E cluster {(µ-t-BuS)[Fe2(CO)6]2(µ4-Se)}2(µ-1-SeCH2C6H4CH2Se-2-µ) (10)
or double butterfly Fe/E cluster (µ-t-BuS)[(µ-1-SeCH2-3-BrCH2-5-MeC6H3)[Fe2(CO)6]2 (µ4-
Se) (11) and quadruple butterfly Fe/E cluster {(µ-t-BuS)[Fe2(CO)6]2(µ4-Se)}2(µ-1-SeCH2-5-
MeC6H3CH2Se-3-µ) (12), respectively. All the new products 4-11 have been characterized
1
by elemental analysis, IR, H and 77Se NMR spectroscopy, and for 4, 7, and 9 single-crystal
X-ray diffraction techniques.
In tr od u ction
anions 1 reacted with (µ-S2)Fe2(CO)6 in THF at room
temperature (for E ) S) or from -78 °C to room
temperature (for E ) Se, Te) to give a new type of
The µ-CO-bridged anions of type [(µ-RE)(µ-CO)Fe2-
(CO)6]- (1, E ) S, Se, Te) are rich in chemical reactivi-
ties and have been extensively used as an important
class of synthon to synthesize a variety of novel cluster
complexes.1-23 In previous papers18-20 we reported that
(10) Song, L.-C.; Hu, Q.-M. J . Organomet. Chem. 1991, 414, 219.
(11) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J .; Mak, T. C. W.
Organometallics 1995, 14, 5513.
(12) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wu, B.-M.; Mak, T. C. W.
Organometallics 1997, 16, 632.
* Corresponding author. Fax: +86-22-23504853. E -mail: lcsong@
public.tpt.tj.cn.
(13) Song, L.-C.; Fan, H.-T.; Hu, Q.-M.; Qin, X.-D. Zhu, W.-F.; Chen
Y.; Sun J . Organometallics 1998, 17, 3454.
(14) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J .; Mak, T. C. W.;
Huang, X.-Y. Organometallics 1996, 15, 1535.
(15) Song, L.-C.; Qin, X.-D.; Hu, Q.-M.; Huang, X.-Y. Organometallics
1998, 17, 5437.
(16) 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.
(17) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Sun, J . Organometallics 1999,
18, 2700.
(18) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Fan, H.-T.; Chen, Y.; Sun J .
Organometallics 1999, 18, 3258.
(19) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Sun, J . Organometallics 1999,
18, 5429.
(20) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Yang J .; Sun, J . Organomet.
Chem. 2001, 623, 56.
(21) Liu, Y.; Wang, R.; Sun J .; Chen, J . Organometallics 2000, 19,
3498.
(22) Wang, Z. X.; J ia, C.-S.; Zhou, Z.-Y.; Zhou, X.-G. J . Organomet.
Chem. 1999, 580, 201.
† Nankai University.
‡ State Key Laboratory of Organometallic Chemistry.
§ State Key Laboratory of Structural Chemistry.
(1) Seyferth, D.; Womack, G. B.; Dewan, J . C. Organometallics 1985,
4, 398.
(2) Seyferth, D.; Womack, G. B.; Archer, C. M.; Dewan, J . C.
Organometallics 1989, 8, 430.
(3) Seyferth, D.; Hoke, J . B.; Dewan, J . C. Organometallics 1987, 6,
895.
(4) Seyferth, D.; Anderson, L. L.; Davis, W. M. J . Organomet. Chem.
1993, 459, 271.
(5) Seyferth, D.; Ruschke, D. P.; Davis, W. M.; Cowie, M.; Hunter,
A. D. Organometallics 1994, 13, 3834.
(6) Seyferth, D.; Womack, G. B.; Archer, C. M.; Fackler, J . P., J r.;
Marler, D. O. Organometallics 1989, 8, 443.
(7) Seyferth, D.; Hoke, J . B.; Womack, G. B. Organometallics 1990,
9, 2662.
(8) Seyferth, D.; Hoke, J . B. Organometallics 1988, 7, 524.
(9) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Huang, X.-Y. Organometallics
1997, 16, 3769.
(23) Delgado, E.; Hernandez, E.; Rossell, O.; Seco, M.; Puebla, E.
G.; Ruiz, C. J . Organomet. Chem. 1993, 455, 177.
10.1021/om0102549 CCC: $20.00 © 2001 American Chemical Society
Publication on Web 06/21/2001

3294 Organometallics, Vol. 20, No. 15, 2001
Song et al.
Sch em e 1
several strong and very strong absorption bands in the
range 2082-1962 cm-1 for their Fe(CO)3 structural
1
units, whereas the H NMR spectra of 4-12 exhibited
several resonance signals for their respective organic
groups. For example, while product 5 showed one singlet
at 1.47 ppm for t-Bu, one singlet at 4.03 ppm for CH2,
and one multiplet in the range 7.40-7.34 ppm for the
Ph group, product 12 displayed one singlet at 1.43 ppm
for t-Bu, one singlet at 2.35 ppm for Me attached to the
benzene ring, one singlet at 3.76 ppm for CH2 attached
to the Se atom, and one multiplet in the range 7.15-
7.00 ppm for the three protons of the benzene ring. It
is worth noting that although the two protons of each
CH2 group attached to the benzene ring in clusters 4-6,
8, and 10-12 are diastereotopic, they showed only one
singlet, but not an AB quartet. This observation could
be possibly attributed to the negligible influence of the
chiral cluster moiety on the attached CH2 group. Since
77Se NMR spectroscopy is a powerful tool for charac-
terization of organometallic selenium complexes,26 we
determined the 77Se NMR spectra of clusters 4-12. It
is interesting to note that the 77Se NMR spectra of these
clusters all showed one singlet for the µ4-Se atoms (each
attached to four Fe(CO)3 electron-withdrawing groups)
in the range of lower field 278.92-346.38 ppm and one
singlet for the µ2-Se atoms (each attached to two Fe-
(CO)3 electron-withdrawing groups and one correspond-
ing organic group) in the range of higher field 83.44-
272.04 ppm, respectively. Although the 77Se NMR data
of µ2-Se in some similar compounds were reported,17,18
such µ4-Se 77Se NMR data are reported here for the first
time. In addition, it is worthy of note that clusters 6
and 7 exhibited three singlets for their three different
Se atoms and the others displayed two singlets for their
two different Se atoms. This can be clearly seen from
Figure 1, as examplified by clusters 5 and 6.
butterfly Fe/E cluster sulfur-centered anions (µ-RE)(µ-
S-)[Fe2(CO)6]2(µ4-S) (2) (Scheme 1).
24
In view of the similarity of (µ-S2)Fe2(CO)6 with its
25
selenium analogue (µ-Se2)Fe2(CO)6 in structure and
reactivity, it might be expected that anions 1 would
react with (µ-Se2)Fe2(CO)6 through a similar process,18
which involves an initially nucleophilic attack of the
negatively charged Fe atom of 1 at the Se atom of (µ-
Se2)Fe2(CO)6 followed by coordination of the µ3-Se atom
of the intermediate m1 to another Fe atom and con-
comitant loss of the µ-CO ligand, to give another new
type of butterfly Fe/E cluster selenium-centered anions
(µ-RE)(µ-Se-)[Fe2(CO)6]2(µ4-Se) (3) (Scheme 2).
In this paper we describe the formation of such a new
type of selenium-centered anions 3 and their in situ
reactions with organic mono- and dihalides, as well as
the structural characterization of the products by means
of spectroscopic and X-ray diffraction techniques.
Resu lts a n d Discu ssion
F or m a tion of An ion s 3 a n d Th eir Rea ction s w ith
Or ga n ic Ha lid es. Syn th esis a n d Sp ectr oscop ic
Ch a r a cter iza tion of 4-12. As the expectation men-
tioned above, the [Et3NH]+ salts of anions [(µ-RE)(µ-
CO)Fe2(CO)6]- (E ) S, Se) (1) (prepared from Fe3(CO)12,
REH (E ) S, Se), and Et3N) or the [MgBr]+ salts of
anions [(µ-RE)(µ-CO)Fe2(CO)6]- (E ) Te) (1) (prepared
from RMgBr, elemental Te, and Fe3(CO)12) reacted with
(µ-Se2)Fe2(CO)6 in THF at -78 °C to give the corre-
sponding salts of the selenium-centered anions (µ-RE)-
(µ-Se-)[Fe2(CO)6]2(µ4-Se) (E ) S, Se, Te) (3) (Scheme 2),
which reacted further with an excess amount of organic
monohalides MeI and PhCH2Br to produce a series of
double butterfly Fe/E cluster complexes (µ-RE)(µ-R1Se)-
[Fe2(CO)6]2(µ4-Se) (4-9) (Scheme 3).
Finally, it should be pointed out that since clusters
4-12 are µ4-Se-containing complexes, the R, R1, 1,2-
(CH2)2C6H4 or 1-CH2-3-BrCH2-5-MeC6H3, and 1,3-(CH2)2-
5-MeC6H3 organic groups are all attached to the bridged
S, Se, and Te atoms by an equatorial (but not axial) type
of bond, to avoid the strong steric repulsions of the
axially bonded structural unit at µ4-Se with the corre-
sponding organic group.9,14,24b This is completely con-
Similarly, if the [Et3NH]+ salt of the anion 3 (RE )
t-BuS) reacted in situ with an excess quantity of
dihalides 1,2-(BrCH2)2C6H4 or 1,3,5-(BrCH2)2MeC6H3,
the corresponding quadruple butterfly Fe/E cluster
complex {(µ-t-BuS)[Fe2(CO)6]2(µ4-Se)}2(µ-1-SeCH2C6H4-
CH2Se-2-µ) (10) or the corresponding double butterfly
Fe/E cluster complex (µ-t-BuS)[(µ-1-SeCH2-3-BrCH2-5-
MeC6H3)[Fe2(CO)6]2(µ4-Se) (11) and quadruple butterfly
Fe/E cluster complex {(µ-t-BuS)[Fe2(CO)6]2(µ4-Se)}2(µ-
1-SeCH2-5-MeC6H3CH2Se-3-µ) (12) were obtained, re-
spectively (Scheme 4).
1
sistent with the H and 77Se NMR data discussed above
and has been further confirmed by X-ray crystal dif-
fraction analyses for clusters 4, 7, and 9.
Cr ysta l Molecu la r Str u ctu r es of 4, 7, a n d 9. To
further confirm the structures of clusters 4-12, single-
crystal X-ray diffraction analyses for 4, 7, and 9 were
carried out. Tables 1-3 list the selected bond lengths
and angles. Figures 2-4 show their molecular struc-
tures.
As can be seen from Figures 2-4, the molecules of 4,
7, and 9 indeed consist of two different structural units,
(µ-EtS)Fe2(CO)6 and (µ-PhCH2Se)Fe2(CO)6 for 4, (µ-p-
MeC6H4Se)Fe2(CO)6 and (µ-MeSe)Fe2(CO)6 for 7, and (µ-
p-MeC6H4Te)Fe2(CO)6 and (µ-MeSe)Fe2(CO)6 for 9, joined
together by a spiro-type four-coordinate Se atom, µ4-
Se. In each molecule of 4, 7, and 9 this µ4-Se is situated
on the center of a distorted tetrahedron constructed by
The butterfly clusters 4-12 are air-stable, red solids,
which have been characterized by elemental analysis
and spectroscopy. The IR spectra of 4-12 showed
(24) (a) Wei, C. H.; Dahl, L. F. Inorg. Chem. 1965, 4, 1. (b) Seyferth,
D.; Henderson, R. S.; Song, L.-C. Organometallics 1982, 1, 125. (c)
Seyferth, D.; Henderson, R. S.; Song, L.-C.; Womack, G. B. J .
Organomet. Chem. 1985, 292, 9.
(25) (a) Campana, C. F.; Lo, F. Y.-K.; Dahl, L. F. Inorg. Chem. 1979,
18 (8), 3060. (b) Seyferth, D.; Henderson, R. S. J . Organomet. Chem.
1981, 204, 333. (c) Mathur, P.; Hossain, Md. M. Organometallics 1993,
12, 2398.
(26) (a) Mathur, P.; Hossain, Md. M.; Umbarkar, S. B.; Satya-
narayana, C. V. V.; Tavale, S. S.; Puranik, V. G. Organometallics 1995,
14, 959. (b) Van Hal, J . W. Whitmire, K. H. Organometallics 1998, 17,
5197.

Double Butterfly Fe/ E Cluster Complexes
Organometallics, Vol. 20, No. 15, 2001 3295
Sch em e 2
Sch em e 3
Sch em e 4
F igu r e 1. 77Se NMR spectra of compounds 5 and 6.
four Fe atoms, and the two different alkylchalcogenido
ligands bridge the four Fe atoms to form a double
butterfly Fe/E (E ) S, Se, Te) cluster complex.
Although the two µ4-Se-containing analogues with
identical alkylchalcogenido ligands µ4-selenidobis[(µ-
ethylsulfido)hexacarbonyldiiron] (abbreviated as SESU,
hereafter), [(µ-EtS)Fe2(CO)6]2(µ4-Se),14 and µ4-seleni-
dobis[(µ-4-tolylselenido)hexacarbonyldiiron] (abbrevi-
ated as STSE, hereafter), [(µ-p-MeC6H4Se)Fe2(CO)6]2(µ4-
Se),27 are known to be structurally characterized, clusters
4, 7, and 9 are so far the first examples of µ4-Se double
butterfly Fe/E clusters with different alkylchalcogenido

3296 Organometallics, Vol. 20, No. 15, 2001
Song et al.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 4
Se(1)-Fe(4)
Se(1)-Fe(1)
Se(2)-C(13)
Se(2)-Fe(4)
Fe(1)-Fe(2)
Fe(3)-Fe(4)
2.3462(12)
2.3619(13)
2.004(7)
2.3896(13)
2.5646(17)
2.5938(14)
Se(1)-Fe(3)
Se(1)-Fe(2)
Se(2)-Fe(3)
Fe(1)-S(1)
Fe(2)-S(1)
S(1)-C(20)
2.3500(12)
2.3629(12)
2.3856(14)
2.269(2)
2.260(3)
1.838(10)
Fe(4)-Se(1)-Fe(3)
67.05(4) Fe(3)-Se(1)-Fe(1) 129.27(5)
Fe(4)-Se(1)-Fe(2) 135.63(5) Fe(3)-Se(1)-Fe(2) 131.94(5)
Fe(1)-Se(1)-Fe(2)
S(1)-Fe(1)-Se(1)
S(1)-Fe(1)-Fe(2)
Se(1)-Fe(3)-Fe(4)
65.75(4) Fe(3)-Se(2)-Fe(4)
76.58(7) Se(1)-Fe(1)-Fe(2)
55.33(8) Se(1)-Fe(3)-Se(2)
56.40(3) Se(2)-Fe(3)-Fe(4)
65.80(4)
57.14(4)
79.01(4)
57.17(4)
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 7
Se(2)-Fe(1)
Fe(1)-Fe(2)
Fe(2)-Se(1)
Fe(3)-Se(3)
Fe(4)-Se(2)
Se(1)-C(13)
2.3499(14)
2.6005(18)
2.3816(17)
2.4021(16)
2.3467(15)
1.960(11)
Se(1)-Fe(1)
Fe(2)-Se(2)
Fe(3)-Se(2)
Fe(3)-Fe(4)
Fe(4)-Se(3)
Se(3)-C(14)
2.3908(17)
2.3520(15)
2.3628(15)
2.594(2)
2.3974(16)
1.944(9)
F igu r e 2. ORTEP drawing of 4 with atom-labeling
scheme.
Se(2)-Fe(1)-Se(1)
Se(1)-Fe(1)-Fe(2)
Se(2)-Fe(3)-Fe(4)
Fe(2)-Se(1)-Fe(1)
78.60(5) Se(2)-Fe(1)-Fe(2)
56.81(5) Se(2)-Fe(2)-Se(1)
56.28(5) Se(3)-Fe(3)-Fe(4)
56.46(4)
78.74(5)
57.19(5)
66.04(5) Fe(4)-Se(2)-Fe(1) 135.60(6)
Fe(4)-Se(2)-Fe(2) 133.97(6) Fe(1)-Se(2)-Fe(2)
Fe(4)-Se(2)-Fe(3) 66.85(5) Fe(3)-Se(3)-Fe(4)
67.16(5)
65.44(5)
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 9
Te(1)-Fe(2)
Fe(1)-Se(1)
Fe(2)-Se(1)
Fe(3)-Se(2)
Fe(4)-Se(1)
2.5663(16)
2.3458(19)
2.3669(17)
2.3938(18)
2.3569(17)
Te(1)-Fe(1)
Fe(1)-Fe(2)
Fe(3)-Se(1)
Fe(3)-Fe(4)
Fe(4)-Se(2)
2.5673(17)
2.608(2)
2.3614(19)
2.575(2)
2.3980(19)
F igu r e 3. ORTEP drawing of 7 with atom-labeling
scheme.
Fe(2)-Te(1)-Fe(1)
Se(1)-Fe(1)-Fe(2)
Se(1)-Fe(2)-Te(1)
Te(1)-Fe(2)-Fe(1)
Se(1)-Fe(3)-Fe(4)
Se(1)-Fe(4)-Fe(3)
61.06(5) Se(1)-Fe(1)-Te(1) 79.34(6)
56.79(5) Te(1)-Fe(1)-Fe(2) 59.45(5)
78.98(5) Se(1)-Fe(2)-Fe(1) 56.02(5)
59.49(5) Se(1)-Fe(3)-Se(2) 78.14(6)
56.83(5) Se(2)-Fe(3)-Fe(4) 57.57(5)
57.00(5) Se(2)-Fe(4)-Fe(3) 57.41(5)
Fe(1)-Se(1)-Fe(4) 133.71(7) Se(1)-Fe(4)-Se(2) 78.14(6)
Fe(1)-Se(1)-Fe(2) 67.19(6) Fe(3)-Se(1)-Fe(4) 66.16(6)
ligands prepared and characterized by crystal X-ray
diffraction.
In fact, 4, 7, and 9 are structurally similar to those
of their analogues SESU and STSE. It can be seen
intuitively from Figures 2-4 that the two different
organic groups (Et and PhCH2 for 4; p-MeC6H4 and Me
for 7 and 9), just like the two identical groups (Et in
SESU; p-MeC6H4 in STSE), are attached to µ2-chalcogen
atoms by an equatorial type of bond.
F igu r e 4. ORTEP drawing of 9 with atom-labeling
scheme.
Con clu sion s
of practical applications in the synthesis of a new class
of mixed transition metal/chalcogen butterfly cluster
complexes.
The reductive cleavage of the Se-Se bond of (µ-Se2)-
Fe2(CO)6 by the Fe-centered anionic nucleophiles [(µ-
RE)(µ-CO)Fe2(CO)6]- (1, E ) S, Se, Te) is first demon-
strated to give a new type of selenium-centered anions
(µ-RE)(µ-Se-)[Fe2(CO)6]2(µ4-Se) (3). More interestingly,
the in situ reactions of anions 3 with mono- and
dihalides can afford a series of new Fe/E cluster
complexes containing one or two double butterfly struc-
tural units (µ-RE)(µ-Se)[Fe2(CO)6]2(µ4-Se) (E ) S, Se,
Te). Apparently, these results highlight the possibility
Exp er im en ta l Section
Gen er a l Com m en ts. All reactions were carried out under
an atmosphere of highly purified nitrogen using standard
Schlenk and vacuum-line techniques. Tetrahydrofuran (THF)
was distilled under nitrogen from sodium/benzophenone ketyl,
and triethylamine from potassium hydroxide. MeI, PhCH2Br,
EtSH, and t-BuSH were commercially available and used
without further purification. Fe3(CO)12,28 p-MeC6H4SeH,29
(µ-Se)2Fe2(CO)6,30 1,2-(BrCH2)2C6H4,31 and 1,3,5-(BrCH2)2-
(27) Song, L.-C.; Hu, Q.-M.; Yan, C.-G.; Wang R.-J .; Mak, T. C. W.
Acta Crystallogr. 1996, C52, 1357.
32
MeC6H3 were prepared according to the literature. The

Double Butterfly Fe/ E Cluster Complexes
Organometallics, Vol. 20, No. 15, 2001 3297
Ta ble 4. Cr ysta l Da ta a n d Str u ctu r a l Refin em en ts Deta ils for 4, 7, a n d 9
4
7
9
mol formula
mol wt
cryst syst
space group
a/ Å
b/Å
c/Å
C
21H12Fe4O12SSe2
C20H10Fe4O12Se3
902.56
C20H10Fe4O12Se2Te
951.20
triclinic
P1h
9.217(3)
10.060(3)
16.890(5)
106.742(6)
104.268(5)
90.759(6)
1447.5(8)
2
869.69
orthorhombic
Pbca
9.3240(6)
17.5418(12)
36.729(3)
90
monoclinic
P2(1)/c
19.1272(11)
9.1357(5)
16.5772(9)
90
93.4400(10)
90
2891.5(3)
4
R/deg
â/deg
90
90
γ/deg
V/Å3
6007.3(7)
8
1.923
Z
Dc/g cm-3
2.073
2.182
F(000)
3376
4.441
293
1728
5.799
293
900
5.522
293
abs coeff/mm-1
temp/K
wavelength/Å
scan type
2θmax/deg
no. of observns, n
no. of variables, p
R
0.71073
ω-2θ
0.71073
ω-2θ
0.71073
ω-2θ
50.06
50.02
50.04
5306
370
0.0548
0.1330
1.124
5077
352
0.0552
0.1138
1.290
0.882 and -0.496
5084
352
0.0511
0.0930
0.853
0.837 and -1.084
Rw
goodness of fit
largest diff peak and hole/e Å-3
0.968 and -0.496
products were separated by TLC (20 × 25 × 0.25 cm, silica
gel G) and further purified by recrystallization from mixed
CH2Cl2/hexane solvent. IR spectra were recorded on a Nicolet
but using 0.05 mL (0.47 mmol) of t-BuSH instead of EtSH.
The major band gave 0.313 g (70%) of 5 as a red solid, mp 146
°C dec. Anal. Calcd for C23H16Fe4O12SSe2: C, 30.77; H, 1.80.
Found: C, 30.49; H, 1.73. IR (KBr disk): νCtO, 2078(s), 2032-
1
170 SX FT IR spectrophotometer, and H NMR and 77Se NMR
(vs), 2014(s), 1995(vs), 1980(vs) cm-1 1H NMR (acetone-d6):
.
spectra on a Bruker AC-P200 NMR spectrometer. Ph2Se2 was
used as an external standard, and the chemical shifts were
referenced to Me2Se (δ 0) for 77Se NMR spectra. C/H analyses
were performed on an Elementa Vario EL analyzer. Melting
points were determined on a Yanaco MP-500 apparatus.
1.47(s, 9H, C(CH3)3), 4.03(s, 2H, CH2), 7.34-7.40(m, 5H, C6H5)
ppm. 77Se NMR (CDCl3, Me2Se): 249.12(s, SeCH2Ph), 346.38-
(s, µ4-Se) ppm.
P r epar ation of (µ-p-MeC6H4Se)(µ-P h CH2Se)[Fe2(CO)6]2-
(µ4-Se) (6). The flask described above was charged with 0.275
g (0.55 mmol) of Fe3(CO)12, 15 mL of THF, 0.085 g (0.50 mmol)
of p-MeC6H4SeH, and 0.08 mL (0.57 mmol) of Et3N. The
mixture was stirred at room temperature for 0.5 h to give a
brown-red solution, which was cooled to -78 °C. To this
solution was slowly added 0.218 g (0.5 mmol) of (µ-Se)2Fe2-
(CO)6 in 10 mL of THF. The mixture was stirred for 2 h at
-78 °C, and then 0.12 mL (1.00 mmol) of PhCH2Br was added.
The mixture was warmed naturally to room temperature and
was stirred for an additional 16 h. The resulting mixture was
filtered, and the filtrate was condensed under reduced pres-
sure. The residue was subjected to TLC separation using CH2-
Cl2/petroleum ether (v/v ) 1:20) as eluent. From the first
brown-red band was obtained 0.060 g (19%) of (µ-p-MeC6H4-
Se)2Fe2(CO)6, which was identified by comparison of its melting
point and 1H NMR spectrum with those of an authentic
sample.11 From the second red band was obtained 0.098 g
P r ep a r a tion of (µ-EtS)(µ-P h CH2Se)[F e2(CO)6]2(µ4-Se)
(4). A 100 mL three-necked flask equipped with a magnetic
stir-bar, a N2 inlet tube, and a serum cap was charged with
0.275 g (0.55 mmol) of Fe3(CO)12, 15 mL of THF, 0.04 mL (0.54
mmol) of EtSH, and 0.08 mL (0.57 mmol) of Et3N. The mixture
was stirred at room temperature for 0.5 h to give a yellow-
brown solution, which was cooled to -78 °C. To this solution
was slowly added 0.218 g (0.50 mmol) of (µ-Se)2Fe2(CO)6 in 10
mL of THF. The mixture was stirred at -78 °C for 1.5 h, and
then 0.12 mL (1.00 mmol) of PhCH2Br was added. The mixture
was warmed naturally to room temperature and was stirred
for an additional 12 h. The resulting mixture was filtered, and
the filtrate was condensed under reduced pressure. The
residue was subjected to TLC separation using petroleum ether
as eluent. The first major red band afforded 0.110 g (51%) of
(µ-EtS)2Fe2(CO)6, which was identified by comparison of its
melting point and 1H NMR spectrum with those of an
authentic sample.33 The second major red band gave 0.100 g
(20%) of 6 as a red solid, mp 178 °C dec. Anal. Calcd for C26H14
-
(23%) of 4 as a red solid, mp 125 °C dec. Anal. Calcd for C21H12
-
Fe4O12Se3: C, 31.91; H, 1.44. Found: C, 31.87; H, 1.42. IR (KBr
Fe4O12SSe2: C, 29.00; H, 1.39. Found: C, 29.11; H, 1.23. IR
disk): νCtO, 2078(s), 2031(vs), 2007(s), 1997(vs), 1988(vs), 1978-
(KBr disk): νCtO, 2082(s), 2056(vs), 2032(vs), 1986(vs) cm-1
.
1
(s) cm-1. H NMR (acetone-d6): 2.26(s, 3H, CH3), 4.06(s, 2H,
1H NMR (acetone-d6): 1.38(t, J ) 10.8 Hz, 3H, CH3), 2.59(q,
J ) 10.8 Hz, 2H, CH2), 4.03(s, 2H, CH2Ph), 7.33-7.41(m, 5H,
C6H5) ppm. 77Se NMR (CDCl3, Me2Se): 247.97(s, SeCH2Ph),
310.07(s, µ4-Se) ppm.
CH2Ph), 7.10-7.42(m, 9H, C6H5, C6H4) ppm. 77Se NMR (CDCl3,
Me2Se): 248.92(s, SeCH2Ph), 261.33(s, Se-Tol), 285.04(s, µ4-
Se) ppm.
P r ep a r a tion of (µ-p-MeC6H4Se)(µ-MeSe)[F e2(CO)6]2(µ4-
Se) (7). The procedure for preparation of 7 is similar to that
of 6, but using 0.06 mL (0.97 mmol) of MeI instead of PhCH2-
Br. From the first brown-red band was obtained 0.078 g (25%)
of (µ-p-MeC6H4Se)2Fe2(CO)6, which was identified by compari-
son of its melting point and 1H NMR spectrum with those of
an authentic sample.11 From the second red band was obtained
0.081 g (18%) of 7 as a red solid, mp 152 °C dec. Anal. Calcd
for C20H10Fe4O12Se3: C, 26.62; H, 1.12. Found: C, 26.69; H,
1.15. IR (KBr disk): νCtO, 2066(s), 2034(vs), 2004(s), 1989(vs),
P r ep a r a tion of (µ-t-Bu S)(µ-P h CH2Se)[F e2(CO)6]2(µ4-Se)
(5). The procedure for preparation of 5 is similar to that of 4,
(28) King R. B. Organometallic Syntheses: Transition Metal Com-
pounds; Academic Press: New York, 1965; Vol. I, p 95.
(29) Foster D. G. Organic Syntheses; Wiley: New York, 1955; Collect.
Vol. III, p 771.
(30) Glidewell, C. J . Organomet. Chem. 1985, 295, 73.
(31) Wenner, W. J . Org. Chem. 1952, 17, 523.
(32) Ried, W.; Konigstein, F. J . Chem. Ber. 1959, 92, 2532.
(33) De Beer, J . A.; Haines, R. J . J . Organomet. Chem. 1970, 24,
757.
1
1966(s) cm-1. H NMR (CDCl3): 2.15(s, 3H, CH3), 2.29(s, 3H,

3298 Organometallics, Vol. 20, No. 15, 2001
Song et al.
1
ArCH3), 7.00-7.33(m, 4H, C6H4) ppm. 77Se NMR (CDCl3, Me2-
Se): 83.44(s, SeCH3), 260.70(s, SeCH2Ph), 288.53(s, µ4-Se)
ppm.
was identified by comparison of its melting point and H NMR
spectrum with those of an authentic sample.33 The second
major band gave 0.197 g (29%) of 10 as a red solid, mp 76 °C
dec. Anal. Calcd for C40H26Fe8O24S2Se4: C, 27.98; H, 1.52.
Found: C, 27.83; H, 1.59. IR (KBr disk): νCtO, 2080(s), 2063-
P r epar ation of (µ-p-MeC6H4Te)(µ-P h CH2Se)[Fe2(CO)6]2-
(µ4-Se) (8). The flask described above was charged with 0.383
g (3. 0 mmol) of Te powder, 20 mL of THF, and 3.0 mmol of
p-MeC6H4MgBr in THF. The mixture was refluxed for 2.5 h
to give a brown-yellow solution. Upon cooling the solution to
room temperature, 1.50 g (3.0 mmol) of Fe3(CO)12 was added,
and the reaction mixture was stirred for 2 h. After cooling this
mixture to -78 °C, 0.874 g (2.0 mmol) of (µ-Se2)Fe2(CO)6 was
added, the mixture was stirred for 1 h at this temperature,
and 0.48 mL (4.0 mmol) of PhCH2Br was added. The mixture
was warmed naturally to room temperature and was stirred
for an additional 18 h. The resulting mixture was filtered, and
the filtrate was condensed under reduced pressure. The
residue was subjected to TLC separation using CH2Cl2/
petroleum ether (v/v ) 1:20) as eluent. From the first major
red band was obtained 0.270 g (25%) of (µ-p-MeC6H4Te)2Fe2-
(CO)6, which was identified by comparison of its melting point
and 1H NMR spectrum with those of an authentic sample.9
From the second major orange-red band was obtained 0.237 g
(vs), 2031(vs), 1983(vs) cm-1 1H NMR (acetone-d6): 1.46(s,
.
18H, 2C(CH3)3), 4.16(s, 4H, 2CH2), 7.12-7.50(m, 4H, C6H4)
ppm. 77Se NMR (CDCl3, Me2Se): 226.64(s, SeCH2Ph), 339.80-
(s, µ4-Se) ppm.
P r epar ation of (µ-t-Bu S)(µ-1-SeCH2-3-Br CH2-5-MeC6H3)-
[F e2(CO)6]2(µ4-Se) (11) a n d {(µ-t-Bu S)[F e2(CO)6]2(µ4-Se)}2-
(µ-1-SeCH2-5-MeC6H3CH2Se-3-µ) (12). The procedure for
preparation of 11 and 12 is similar to that of 10, but using
0.139 g (0.5 mmol) of 1,3,5-(BrCH2)2MeC6H3 instead of 1,2-
(BrCH2)2C6H4. The first major band afforded 0.124 g (25%) of
11 as a red solid, mp 121 °C dec. Anal. Calcd for C25H19
BrFe4O12SSe2: C, 29.89; H, 1.91. Found: C, 29.80; H, 1.95. IR
(KBr disk): νCtO, 2082(s), 2034(vs), 1989(vs), 1962(vs) cm-1
-
.
1H NMR (CDCl3): 1.43(s, 9H, C(CH3)3), 2.35(s, 3H, CH3), 3.76-
(s, 2H, SeCH2), 4.44(s, 2H, BrCH2), 7.00-7.13(m, 3H, C6H3)
ppm. 77Se NMR (CDCl3, Me2Se): 248.24(s, SeCH2Ar), 344.88-
(s, µ4-Se) ppm. The second major band gave 0.143 g (17%) of
12 as a red solid, mp 116 °C dec. Anal. Calcd for C41H28Fe8O24
S2Se4: C, 28.44; H, 1.63. Found: C, 28.55; H, 1.92. IR (KBr
(12%) of 8 as a red solid, mp 185 °C dec. Anal. Calcd for C26H14
-
Fe4O12Se2Te: C, 30.40; H, 1.37. Found: C, 30.45; H, 1.40. IR
(KBr disk): νCtO, 2082(s), 2034(vs), 2001(vs), 1985(vs), 1969-
(vs) cm-1. 1H NMR (CDCl3): 2.32(s, 3H, CH3), 3.84(s, 2H, CH2),
7.03-7.42(m, 9H, C6H5, C6H4) ppm. 77Se NMR (CDCl3, Me2-
Se): 250.89(s, SeCH2Ph), 275.15(s, µ4-Se) ppm.
disk): νCtO, 2082(s), 2034(vs), 2007(s), 1981(vs), 1966(s) cm-1
.
1H NMR (CDCl3): 1.43(s, 18H, 2C(CH3)3), 2.35(s, 3H, CH3),
3.76(s, 4H, 2CH2), 7.00-7.15(m, 3H, C6H3) ppm. 77Se NMR
(CDCl3, Me2Se): 248.54(s, SeCH2Ar), 344.27(s, µ4-Se) ppm.
Sin gle-Cr ysta l Str u ctu r e Deter m in a tion s of 4, 7, a n d
9. Single crystals of 4, 7, and 9 suitable for X-ray diffraction
analyses were grown by slow evaporation of their CH2Cl2/
hexane solutions at about 5 °C. The single crystals of 4 (0.20
× 0.35 × 0.40), 7 (0.42 × 0.18 × 0.18), and 9 (0.35 × 0.20 ×
0.10) were glued to a glass fiber and mounted on a Bruker
SMART 1000 or a SMART CCD automated diffractometer.
Details of the crystal data, data collections, and structure
refinements are summarized in Table 4. The structures were
solved by direct methods and expanded by Fourier techniques.
The final refinements were accomplished by the full-matrix
least-squares method with anisotropic thermal parameters for
non-hydrogen atoms. The calculations for 4, 7, and 9 were
performed using the TEXSAN crystallographic software pack-
age of the Molecular Structure Corporation.
P r ep a r a tion of (µ-p-MeC6H4Te)(µ-MeSe)[F e2(CO)6]2(µ4-
Se) (9). The procedure for preparation of 9 is similar to that
of 8, but using 0.24 mL (4.0 mmol) of MeI instead of PhCH2-
Br. From the first major red band was obtained 0.290 g (27%)
of (µ-p-MeC6H4Te)2Fe2(CO)6, which was identified by compari-
son of its melting point and 1H NMR spectrum with those of
an authentic sample.9 From the second major orange-red band
was obtained 0.190 g (10%) of 9 as a red solid, mp 128 °C dec.
Anal. Calcd for C20H10Fe4O12Se2Te: C, 25.25; H, 1.06. Found:
C, 25.27; H, 1.20. IR (KBr disk): νCtO, 2082(s), 2040(s), 2026-
(vs), 1985(vs), 1971(s) cm-1 1H NMR (CDCl3): 2.13(s, 3H,
.
CH3), 2.31(s, 3H, ArCH3), 7.00-7.30(m, 4H, C6H4) ppm. 77Se
NMR (CDCl3, Me2Se): 85.03(s, SeCH3), 278.92(s, µ4-Se) ppm.
P r ep a r a tion
of {(µ-t-Bu S)[F e2(CO)6]2(µ4-Se)}2(µ-1-
SeCH2C6H4CH2Se-2-µ] (10). The flask described above was
charged with 0.755 g (1.5 mmol) of Fe3(CO)12, 15 mL of THF,
0.17 mL (1.5 mmol) of t-BuSH, and 0.24 mL (1.7 mmol) of Et3N.
The mixture was stirred at room temperature for 0.5 h to give
a brown-red solution, which was cooled to -78 °C. To this
solution was slowly added 0.437 g (1.0 mmol) of (µ-Se)2Fe2-
(CO)6 in 10 mL of THF. The mixture was stirred for 2 h at
-78 °C, and then 0.105 g (0.4 mmol) of 1,2-(BrCH2)2C6H4 was
added. The mixture was warmed naturally to room tempera-
ture and was stirred for an additional 18 h. The resulting
mixture was filtered, and the filtrate was condensed under
reduced pressure. The residue was subjected to TLC separation
using petroleum ether as eluent. From the first brown-red
band was obtained 0.075 g (11%) of (t-BuS)2Fe2(CO)6, which
Ack n ow led gm en t. We are grateful to the National
Natural Science Foundation of China, the State Key
Laboratory of Organometallic Chemistry, and the State
Key Laboratory of Structural Chemistry for financial
support of this work.
Su p p or tin g In for m a tion Ava ila ble: Full tables of crystal
data, atomic coordinates and thermal parameters, and bond
lengths and angles for 4, 7, and 9. This material is available
free of charge via the Internet at http://pubs. acs.org.
OM0102549