Reaction of a thienyl schiff base with diiron nonacarbonyl: Characterization and structures of [μ-N-(((2,3-η1:η 2)-5-methyl-2-thienyl)methyl)-η1:η1 (N)-anilino]hexacarbonyldiiron and [μ-N-((anilino(2-thienyl)methyl) ((2,3-η1:η2)-2-thienyl)methyl)-η 1:η1(N)

Article abstract of DOI:10.1021/om961092x

When thienyl Schiff base 1 reacted with Fe₂(CO)₉ under very mild conditions in benzene three major products were obtained: (1) a cyclometalated (μ-η¹:η²-thienyl; η¹:η¹(N))-hexacarbonyldiiron complex, 2, (2) a hexacarbonyldiiron complex with an organic ligand, which is composed of two thienyl moieties derived from the original thienyl imine and coupled together by a C-C bond, 3, and (3) a hydrogenation product of the original thienyl Schiff base. Molecular structures of compounds 2b and 3a have been determined by single-crystal X-ray diffraction.

Full text of DOI:10.1021/om961092x

Organometallics 1997, 16, 3109-3113
3109
Rea ction of a Th ien yl Sch iff Ba se w ith Diir on
Non a ca r bon yl: Ch a r a cter iza tion a n d Str u ctu r es of
[µ-N-(((2,3-η1:η2)-5-Meth yl-2-th ien yl)m eth yl)-η1:η1(N)-
a n ilin o]h exa ca r bon yld iir on a n d
[µ-N-((An ilin o(2-th ien yl)m eth yl)((2,3-η1:η2)-2-th ien yl)m eth yl)-
η1:η1(N)-a n ilin o]h exa ca r bon yld iir on
Dong-Liang Wang and Wen-Shu Hwang*
Department of Chemistry, National Dong Hwa University, Hualien, Taiwan, ROC
Lan-Chang Liang, Lien-I Wang, Liangshiu Lee, and Michael Y. Chiang
Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan, ROC
Received December 23, 1997X
When thienyl Schiff base 1 reacted with Fe2(CO)9 under very mild conditions in benzene
three major products were obtained: (1) a cyclometalated (µ-η1:η2-thienyl; η1:η1(N))-
hexacarbonyldiiron complex, 2, (2) a hexacarbonyldiiron complex with an organic ligand,
which is composed of two thienyl moieties derived from the original thienyl imine and coupled
together by a C-C bond, 3, and (3) a hydrogenation product of the original thienyl Schiff
base. Molecular structures of compounds 2b and 3a have been determined by single-crystal
X-ray diffraction.
In tr od u ction
biological interest.6 The (µ-η1:η2-thienyl; η1:η1(N))hexa-
carbonyldiiron complexes show a unique binding mode
in that the â-carbon and a CdC π bond of the bridging
thiophene and the nitrogen atom all are coordinated to
the diiron (Fe-Fe) unit. Of the various modes of
thiophene coordination in transition metal complexes,
this mode is rarely encountered. It can be regarded as
the combination of an η1-C-bound and an η2-π-bound
mode applied on two different metal centers. This
compound is very interesting in that despite the limited
coordination ability of thiophene and the steric con-
straints of the ligand, thiophene is able to bind to both
metals.
The coordination chemistry of thiophene is currently
attracting attention. However, most of the known
thiophene complexes are monometallic and the binding
of thiophene ligands to more than one transition metal
is relatively rare. Since the late 1980s, advances have
been made in understanding the coordination of thio-
phene in transition metal complexes.1 The results have
led to a more profound comprehension of the mecha-
nisms involved in the hydrodesulfurization process, as
shown by the work of Angelici et al.2 Because of the
variety of binding modes between thiophene and metals,
the topic is still of great interest from a structural point
of view. Furthermore, development of a correlation
between particular binding modes and the various
patterns of reactivity is a continuing effort for many
research groups.2,3 The interesting aspect of sulfur
atom coordination in transition metal complexes is well-
demonstrated by Seyferth et al.4,5 In their work,
reagents containing the hexacarbonyldiiron moiety show
many diverse reactions. We report here the preparation
and characterization of complexes in which a ligand
containing a thiophene group coordinates to a diiron
(Fe-Fe) unit. The original ligand is a Schiff base
derived from 2-thiophenecarboxaldehyde, which under-
goes cyclometalation, hydrogenation, or C-C coupling
during the course of its reaction with Fe2(CO)9. The
choice of a heterocyclic Schiff base also stems from their
Furthermore, the coupling reactions between various
types of organic ligands are important for their rel-
evance to catalysis and organic synthesis.7 The metal-
mediated C-C coupling reactions are quite common.8
We observe products resulting from the metal-mediated
C-H activation and C-C coupling reactions in the
reactions reported herein.
Resu lts a n d Discu ssion
The thienyl Schiff base N-(2-thienylmethylidene)-
aniline (1a ) reacts with diiron nonacarbonyl under very
mild conditions in anhydrous benzene to give two diiron
complexes, which we formulate as 2a and 3a , and an
X Abstract published in Advance ACS Abstracts, J une 1, 1997.
(1) Angelici, R. J . Coord. Chem. Rev. 1990, 105, 61.
(2) Benson, J . W.; Angelici, R. J . Organometallics 1993, 12, 660 and
references cited therein.
(3) (a) Polam, J . R.; Porter, L. C. Organometallics 1993, 12, 3504.
(b) Luo, S.; Rauchfuss, T. B.; Gan, Z. J . Am. Chem. Soc. 1993, 115,
4943. (c) Benson, J . W.; Angelici, R. J . Inorg. Chem. 1993, 32, 1871.
(4) Seyferth, D.; Archer, C. M.; Ruschke, D. P.; Cowie, M.; Hilts, R.
W. Organometallics 1991, 10, 3363.
(6) Sovill, J .; Klayman, C. F. J . Med. Chem. 1982, 25, 126.
(7) Ryabov, A. D. Chem. Rev. 1990, 90, 403.
(8) See for examples: (a) Alvarez, B.; Garc´ıa-Granda, S.; Li, J .;
Miguel, D.; Riera, V. Organometallics 1994, 13, 16. (b) Valero, C.;
Grehl, M.; Wingbermu¨hle, D.; Kloppenburg, L.; Carpenetti, D.; Erker,
G.; Petersen, J . L. Organometallics 1994, 13, 415. (c) Lu, K. L.; Chen,
H. L.; Lu, P. Y.; Li, S. Y.; Hong, F. E.; Peng, S. M.; Lee, G. H.
Organometallics 1994, 13, 585. (d) Filippou, A. C.; Vo¨lkl, C.; Rogers,
R. D. J . Organomet. Chem. 1993, 463, 135. (e) van Wijnkoop, M.;
Siebenlist, R.; de Lange, P. P. M.; Smeets, W. J . J .; Vrieze, K.
Organometallics 1993, 12, 4172.
(5) Seyferth, D.; Anderson, L. L.; Villafan˜e, F.; Cowie, M.; Hilts, R.
W. Organometallics 1992, 11, 3262.
S0276-7333(96)01092-8 CCC: $14.00 © 1997 American Chemical Society

3110 Organometallics, Vol. 16, No. 14, 1997
Wang et al.
Sch em e 1
Ta ble 1. Cr ysta l a n d Da ta Collection P a r a m eter s
for Com p ou n d s 2b a n d 3a
organic product, 4a , as the major products (Scheme 1).
The presence of a NH functional group and the
absence of a CdN stretching frequency in the IR
spectrum indicate that compound 4a is a product of
hydrogenation of the original imine. The elemental
analysis and other spectral data confirm this. The
hydrogenation of a CN double bond normally requires
more extreme conditions, and there is no doubt that
compound 4a arises as a result of coordination of 1a to
an iron carbonyl. The hydrogenation reaction was also
observed when the reaction medium was anhydrous
THF (vide infra) or deuterated benzene.
compd
formula
fw
2b
3a
C
18HFe2NO6S
C28H18Fe2NO6S2
655
481
cryst syst
space group
a (Å)
b (Å)
c (Å)
triclinic
P1h (No. 2)
8.314(2)
9.302(1)
13.382(3)
84.65(2)
74.59(2)
81.35(2)
984.8(8)
2
monoclinic
P21/c(No. 14)
10.358(2)
8.991(3)
30.871(2)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
95.04(1)
2863.8(9)
4
1.52
1
calc (g/cm3)
1.622
The cyclometalated product 2a is a red oil. The H
D
cryst size (mm)
temp (K)
0.16 × 0.33 × 0.50
0.25 × 0.33 × 0.38
NMR spectrum of 2a shows the absence of the methine
proton (resonance at 8.72 ppm in 1a ), and a singlet
methylene resonance appears at 4.42 ppm. In the
aromatic region, two doublet thiophene protons appear
at δ 7.81 and 7.45 ppm with a coupling constant J H-H
) 5.1 Hz. The integrated intensities clearly show that
only seven aromatic protons are left. In its IR spectrum,
while the CdN stretching is absent, there are three
sharp and intense CdO stretches appearing at 2069,
2032, and 1995 cm-1. This result could be interpreted
by assuming that coordination of the imine nitrogen of
the thienyl Schiff base to one of the iron centers, a
cyclometalation occurs at a â-carbon of the thienyl ring
and the methine group becomes a methylene group by
accepting the hydrogen that was removed from the
â-carbon. The mass spectrum of this product shows the
complete loss of six CO ligands in a sequential manner,
in accordance with the formulated structure.
297
297
2θmax (deg)
50.0
ω-2θ
3689, 3456
50.0
ω-2θ
5726, 5409
scan type
no. of reflns measd:
total, unique
no. of obsd reflns
(1>3.00σ(1))
no. of variables
F000
2897
3262
253
361
484.00
16.07
0.039
0.049
1328.00
12.02
0.039
0.044
µ, (Mo KR) (cm-1
R
Rw
)
pounds 2b, 3b, and 4b exhibit spectral data that very
closely resemble those of 2a , 3a , and 4a , as shown in
the Experimental Section.
A red prism crystal of 2b was subjected to a single-
crystal X-ray analysis. Crystal and data collection
parameters are shown in Table 1. An ORTEP diagram
of one rotamer is shown in Figure 1. Selected bond
distances and bond angles are tabulated in Table 2. It
is readily seen that C3 of the thienyl ring is σ bonded
to Fe2 with a bond distance of 1.959(4) Å. C3 and C2
are bonded to Fe1 with bond distances of 2.156(4) and
2.251(4) Å, respectively. Hence, Fe1 is bonded to
thiophene by the π bond between C2 and C3, and the
bond distance between C2 and C3 is lengthened to
In order to have a better understanding of the
coordination mode and to confirm the structure of
compound 2a , a methyl-substituted thienyl Schiff base
N-(5-methyl-2-thienylmethylidene)aniline (1b) was re-
acted with diion nonacarbonyl under the same condi-
tions. Similar results were obtained, and products 2b,
3b, and 4b were isolated and characterized. Com-

Reaction of a Thienyl Schiff Base with Fe2(CO)9
Organometallics, Vol. 16, No. 14, 1997 3111
F igu r e 1. ORTEP diagram of compound 2b at the 30%
probability level.
Ta ble 2. Selected Bon d Len gth s (Å) a n d Bon d
An gles (d eg) of Com p ou n d 2b
Fe(1)-Fe(2)
Fe(1)-C(3)
Fe(2)-C(3)
C(2)-C(3)
2.4617(9)
2.156(4)
1.959(4)
1.406(5)
Fe(1)-C(2)
Fe(1)-N(1)
Fe(2)-N(1)
C(1)-N(1)
2.251(4)
1.981(3)
2.002(3)
1.491(4)
F igu r e 2. ORTEP diagram of compound 3a at the 30%
probability level. S2 and S3 indicate the packing disorder
of the second thiophene group.
Fe(1)-N(1)-Fe(2)
76.3(1)
Fe(1)-C(3)-Fe(2)
73.3(1)
Ta ble 3. Selected Bon d Len gth s (Å) a n d Bon d
An gles (d eg) of Com p ou n d 3a
1.406(5) Å. This binding involving π electrons of a
thienyl ring has been reported.1 We conclude, therefore,
that the thienyl group in the organic ligand serves as a
three-electron donor and bridges the two iron centers.
The bond distance between C1 and N1, 1.491(4) Å, is
in the single bond range, while the bond distance
between N1 and Fe1 and N1 and Fe2 is 1.981(3) and
2.002(3) Å, respectively. A 36-electron structure can be
rationalized on the supposition that the nitrogen atom
acts as another three-electron bridge in 2b. An iron-
iron distance of 2.4617(9) Å is shorter than usual for
diiron complexes9 but is in accordance with other
nitrogen-bridged diiron complexes.10,11 The Fe1-N-
Fe2 angle is 76.3(1)° and Fe1-C3-Fe2 is 73.3(1)°. The
compression of these two angles from the tetrahedral
value is a result of the ligand constraints of double
bridging, which also brings about the shorter metal-
metal distance. The structure of 2b is analogous to that
of the nitrogen-containing organometallic complexes
reported by Baikie and Mills.10 The ferrocyclopentadi-
ene and ferraindene complexes reported by Braye and
Hu¨bel12 are similar to 2b structurally. In both cases, a
phenyl group acts as bridge instead of a thiophene.
Complex 2b also bears some resemblance to Fe2(CO)6
complexes with bridging η1:η2-vinyl, furyl, and thienyl
ligands reported by Seyferth.4,5
Fe(1)-Fe(2)
Fe(1)-C(3)
Fe(2)-C(3)
C(2)-C(3)
2.444(1)
2.181(4)
1.947(4)
1.389(6)
1.552(5)
Fe(1)-C(2)
Fe(1)-N(1)
Fe(2)-N(1)
C(1)-N(1)
C(18)-N(2)
2.207(4)
1.980(3)
2.007(3)
1.493(5)
1.456(5)
C(1)-C(18)
Fe(1)-N(1)-Fe(2)
N(1)-C(1)-C(2)
C(2)-C(1)-C(18)
75.6(1)
97.2(3)
114.7(3)
Fe(1)-C(3)-Fe(2)
N(1)-C(1)-C(18)
C(1)-C(18)-C(19)
72.4(1)
115.6(3)
113.7(3)
is a µ-η1:η2-thienyl; η1:η1(N) bridge, and structural
parameters are similar to those of 2b. Another moiety
(L′) is fairly free from metal interaction. For example,
a 50:50 packing disorder (50% occupancy factor is
assigned to both S2 and S3) is observed for the thienyl
group that does not bind to either one of the iron centers.
Spectral data of complex 3a are self explanatory and in
accordance with X-ray analysis. Both homonuclear
(1H-1H) and heteronuclear (1H-13C) COSY experiments
were performed to assist the assignments of the NMR
1
spectra. Figure 3 shows the H-1H COSY spectrum of
3a with assignments on the top of the figure. Protons
numbered with primes are those attached to the thienyl
moiety L′. Notably, proton 1′ (δ 4.38 ppm) appears more
upfield than proton 1 (δ 5.05 ppm), an indication that
the aliphatic C-H unit in L is polarized by metal
interactions. In addition, steric constraints from the
hexacarbonyldiiron portion of the complex causes the
phenyl and thienyl groups on L′ to bend to the same
side of C18 (Figure 2). The situation places proton 7′
in the shielding core of the thienyl ring. Therefore, it
has the lowest chemical shift (δ 6.04 ppm) among all
the aromatic protons.
The molecular structure of compound 3a , determined
by a single-crystal X-ray diffraction study, is shown in
Figure 2. Crystal and data collection parameters are
tabulated in Table 1. Selected bond distance and bond
angles are reported in Table 3. There are two thienyl
moieties derived from the original thienyl imine coupled
together by a C-C single bond between C1 and C18
(1.552(5) Å). The moiety (L) that coordinates to diiron
When the reaction medium is THF, the reaction is
for the most part parallel to that in benzene. The most
striking difference is the substantial reduction in yield
of the products. The decrease in polarity of the solvent
seems to increase the stability or encourage the forma-
tion of compounds 2 and 3. In fact, a complex similar
to 3 is not obtained in the case of a reaction carried out
(9) Ogilvy, A. E.; Draganjac, M.; Rauchfuss, T. B.; Wilson, S. R.
Organometallics 1988, 7, 1171.
(10) Baikie, P. E.; Mills, O. S. Chem. Commun. 1966, 707.
(11) De Cain, A.; Weiss, R.; Chauvin, Y.; Commereuc, D.; Hugo, D.
J . Chem. Soc., Chem. Commun. 1976, 249.
(12) Braye, E. H.; Hu¨bel, W. J . Organomet. Chem. 1965, 3, 38.

3112 Organometallics, Vol. 16, No. 14, 1997
Wang et al.
dried (sodium/benzophenone, P4O10) and distilled under ni-
trogen prior to use. All other chemicals were reagent grade
and used without purification. The NMR spectra were re-
corded on either a Varian EM-390 or Varian VXR-300 NMR
spectrometer (1H, 299.95 MHz; 13C, 75.43 MHz). Chemical
shifts were referenced to TMS, and deuterated acetone (J an-
ssen) was used as a solvent and as a secondary reference. Mass
spectra were obtained on a VG-Biotech Quattro 5022 spec-
trometer. IR spectra were recorded on a Bio-Rad FTS-40
spectrometer. Elemental analyses were performed using a
Heraeus CHNO rapid analyzer. Crystals for X-ray diffraction
were obtained by sublimation. A single crystal was mounted
on a glass fiber, and the X-ray diffraction intensity data were
measured on a Rigaku AFC7S diffraction at room temperature.
Syn th esis of N-(2-Th ien ylm eth yliden e)an ilin e (1a) an d
N-(5-Meth yl-2-th ien ylm eth ylid en e)a n ilin e (1b). The syn-
thesis of the Schiff base employed the usual approach of
condensation in alcohol solution.15 Equimolar quantities of
2-thiophenecarboxaldehyde (Aldrich, 3.8 mL, 40 mmol) or
5-methyl-2-thiophenecarboxaldehyde (Aldrich, 4.3 mL, 40
mmol) and aniline (Merck, 3.6 mL, 40 mmol) were heated at
reflux in methanol (Merck, 65 mL) for 12 h. The solvent was
removed under vacuum. The residue was distilled with a
Kugelrohr distillation apparatus under reduced pressure (0.1
mmHg). The orange-red compound 1a was obtained (7.02 g;
94% yield) at 175 °C. 1H NMR: δ 8.72 (s, 1H), 7.69 (d, J )
5.1 Hz, 1H), 7.60 (d, J ) 3.6 Hz, 1H), 7.40 (m, 2H), 7.25 (m,
3H), 7.19 (dd, J ) 3.6, 5.1 Hz, 1H). 13C NMR: δ 153.9, 152.2,
143.9, 133.6, 131.2, 129.9, 128.6, 126.7, 121.7. IR (CHCl3)
F igu r e 3. 1H-1H COSY spectrum of compound 3a in
acetone-d6.
ν
CdN: 1617 cm-1
.
MS (EI): m/z 187 (M+). Anal. Calcd for
C
11H9NS: C, 70.55; H, 4.86; N, 7.48. Found: C, 70.40; H, 4.89;
in THF. However, trace amounts of pentacarbonyldi-
iron complex 5 were isolated. Although complex 5 is
N, 7.51. The orange-red compound 1b was obtained (7.40 g;
92% yield) at 185 °C. 1H NMR: δ 8.60 (s, 1H), 7.42 (d, J )
3.9 Hz, 1H), 7.37 (m, 2H), 7.21 (m, 3H), 6.87 (d, J ) 3.9 Hz,
1H), 2.52 (s, 3H). 13C NMR: δ 153.8, 152.4, 146.3, 141.9, 134.1,
129.9, 127.2, 126.5, 121.7, 16.7. IR (CHCl3) νCdN: 1614 cm-1
MS (EI): m/z 201 (M+), 200 (M+ - H). Anal. Calcd for C12H11
.
-
NS: C, 71.60; H, 5.51; N, 6.96. Found: C, 71.61, H, 5.52; N,
6.95.
Rea ction of 1 w ith F e2(CO)9 in Ben zen e To Give [µ-N-
(((2,3-η1:η2)-2-Th ien yl)m eth yl)-η1:η1(N)-a n ilin o]h exa ca r -
b on yld iir on (2a )/[µ-N-(((2,3-η1:η2)-5-Met h yl-2-t h ien yl)-
m eth yl)-η1:η1(N)-a n ilin o]h exa ca r bon yld iir on (2b), [µ-N-
((An ilin o(2-th ien yl)m eth yl)((2,3-η1:η2)-2-th ien yl)m eth yl)-
η1:η1(N)-an ilin o]h exacar bon yldiir on (3a)/[µ-N-((An ilin o(5-
Me t h y l-2-t h ie n y l)m e t h y l)((2,3-η1:η2)-5-m e t h y l-2-t h i-
en yl)m eth yl)-η1:η1(N)-a n ilin o]h exa ca r bon yld iir on (3b),
a n d N-((2-Th ien yl)m eth yl)a n ilin e (4a )/N-((5-Meth yl-2-
th ien yl)m eth yl)a n ilin e (4b). Eight millimoles of compound
1 in 30 mL of anhydrous benzene was added gradually to 70
mL of anhydrous benzene solution containing 6.0 mmol of Fe2-
(CO)9 in the dark under nitrogen, and the reaction mixture
was stirred for 40 h at 15 °C. The residue was filtered, and
the solvent was removed under reduced pressure. The residue
was separated by a 3.5 cm × 40 cm column (230-400 mesh
ASTM silica gel (Merck)) with ethyl acetate/chloroform/n-
hexane (1:5:20) as eluent. The red band gave a crude product
that was further treated by column chromatography (vide
infra). The orange band produced 135 mg of 4a (11.9% yield)
and 169 mg of 4b (13.9% yield). Compound 4a : 1H NMR δ
7.28 (d, 1H), 7.08 (m, 3H), 6.95 (1H), 6.72 (m, 2H), 6.63 (m,
1H), 5.42 (br, 1H), 4.53 (d, J ) 4.8 Hz, 2H). 13C NMR: δ 149.2,
145.1, 129.7, 127.4, 125.4, 124.9, 117.7, 113.7, 43.4. MS (EI):
m/z 189 (M+). Anal. Calcd for C11H11NS: C, 69.80; H, 5.86;
N, 7.40. Found: C, 69.15; H, 5.88; N, 7.43. Compound 4b:
1H NMR δ 7.10 (m, 2H), 6.80 (1H), 6.71 (m, 2H), 6.62 (m, 2H),
5.32 (br, 1H), 4.43 (d, J ) 4.8 Hz, 2H), 2.39 (s, 3H). 13C NMR:
very unstable, we were able to deduce its structure, as
shown above, by its H NMR, IR, and mass spectra. It
1
contains a bridging carbonyl between the two iron
centers. The bridging carbonyl has a stretching fre-
quency of 1732 cm-1. The broad and intense absorption
at 3416 cm-1 indicates the presence of the -NH group.
The mass spectrum shows the complete loss of five COs
successively, and the molecular ion peak at m/z 630/
658 suggests that two organic ligands 4a /4b are incor-
porated. The simplicity of the 1H NMR spectrum
suggests that the two organic ligands are arranged more
or less symmetrically. Since S-bound thiophene in
transition metal complexes had been reported in many
occasions,13 we suggest that such a possibility also exists
in 5. We suggest that complex 5 is an intermediate in
the formation of the hydrogenation product 4.
Exp er im en ta l Section
Diiron nonacarbonyl was prepared by photolysis of iron
pentacarbonyl (Aldrich) in glacial acetic acid.14 Solvents were
(13) (a) Dong, L.; Duckett, S. B.; Ohman, K. F.; J ones, W. D. J . Am.
Chem. Soc. 1992, 114, 151. (b) Choi, M.-G.; Daniels, L. M.; Angelici,
R. J . Inorg. Chem. 1991, 30, 3647. (c) Choi, M.-G.; Angelici, R. J . J .
Am. Chem. Soc. 1989, 111, 8753. (d) Luo, S. F.; Ogilvy, A. E.;
Rauchfuss, T. B.; Stern, C. L.; Wilson, S. R. Organometallics 1989, 8,
2277.
(14) Shriver, D. F.; Whitmire, K. H. In Comprehensive Organome-
tallic Chemistry; Wilkinson, G., Stone, F. G. A., Abel, E. W., Eds.;
Pergamon: Oxford, 1982; Vol. 4, Chapter 31.1.
(15) Guerriero, P.; Bullita, E.; Vigato, P. A.; Pelli, B.; Traldi, P. J .
Heterocyclic Chem. 1988, 25, 145.

Reaction of a Thienyl Schiff Base with Fe2(CO)9
Organometallics, Vol. 16, No. 14, 1997 3113
δ 149.3, 142.6, 139.0, 129.7, 125.5, 125.3, 117.6, 113.7, 43.4,
15.2. MS (EI): m/z 203 (M+). Anal. Calcd for C12H13NS: C,
70.89; H, 6.44; N, 6.89. Found: C, 70.78; H, 6.44; N, 6.85.
Substantial amounts of Fe3(CO)12 also were collected.
(m, 2H), 7.09 (m, 4H), 6.90 (dd, 2H), 6.49 (m, 3H), 6.05 (d, 2H),
4.86 (d, J ) 6.3 Hz, 1H), 4.36 (d, J ) 6.3 Hz, 1H), 4.26 (dd,
1H), 2.35 (s, 6H). 13C NMR: δ 163.4, 157.9, 150.7, 147.0, 142.4,
140.6, 136.0, 129.9, 129.3, 128.9, 127.2, 126.3, 125.3, 117.8,
113.6, 87.2, 63.4, 15.6, 15.3. IR (CHCl3): νCO 2067, 2026, 1996,
1960 cm-1; νNH 3407 cm-1. UV-vis (CHCl3): λmax 436.0 (ꢀ )
5900 M-1 cm-1), 340.0 (ꢀ ) 19 200 M-1 cm-1) nm. MS (EI):
m/z 683 (M+ + 1), 654 (M+ - CO), 626 (M+ - 2CO), 598 (M+
- 3CO), 570 (M+ - 4CO), 542 (M+ - 5CO), 514 (M+ - 6CO),
202 (L′+). Anal. Calcd for Fe2C30H22N2S2O6: C, 52.79; H, 3.23;
N, 4.10; O, 14.08. Found: C, 53.01; H, 3.21; N, 4.12; O, 14.15.
Rea ction of 1 w ith F e2(CO)9 in THF . The reaction under
the same condition as performed in benzene gave much lower
yields of products 2a /2b (0.6%/0.9%) and 4a /4b (4.4%/6.9%).
A complex similar to 3a /3b was not obtained. However, trace
amount of compound 5a /5b was isolated, and a substantial
amount of Fe3(CO)12 (∼30%) was collected. Compound 5a : 1H
NMR δ 7.61 (1H), 7.45 (1H), 7.29 (1H), 7.12 (2H), 6.84 (1H),
6.73 (2H), 6.08 (1H), 4.78 (2H). IR (CHCl3): νCO 2068, 2030,
1997, 1986, 1732 cm-1; νNH 3416 cm-1. MS (EI): m/z 630 (M+),
The crude product of the red band was purified further by
column chromatography with ethyl acetate/chloroform/n-hex-
ane (1:35:50) as eluent. A red oil, 2a (399 mg, 14.2% yield)/
red solid, 2b (710 mg, 24.6% yield) and a red solid, 3a (123
mg, 3.1% yield)/red solid, 3b (113 mg, 2.8% yield) were isolated.
Compound 2a : 1H NMR δ 7.81 (d, J ) 5.1 Hz, 1H), 7.45 (d, J
) 5.1 Hz, 1H), 7.30 (m, 2H), 7.15 (m, 3H), 4.42 (s, 2H). 13C
NMR: δ 159.3, 158.5, 140.1, 133.3, 129.9, 127.6, 126.7, 124.3,
73.7. IR (CHCl3) νCO
(CHCl3): λmax 465.6 (ꢀ ) 4900 M-1 cm-1), 336 (ꢀ ) 1500 M-1
cm-1) nm. MS (EI): m/z 467 (M+), 439 (M+ - CO), 411 (M+
:
2069, 2032, 1995 cm-1
.
UV-vis
-
2CO), 383 (M+ - 3CO), 355 (M+ - 4CO), 327 (M+ - 5CO),
299 (M+ - 6CO), 187 (L+). Anal. Calcd for Fe2C17H9NSO6:
C, 43.68; H, 1.93; N, 3.00. Found: C, 43.78; H, 1.95; N, 2.98.
Compound 2b: 1H NMR δ 7.30 (m, 2H), 7.14 (m, 4H), 4.33 (s,
2H), 2.50 (s, 3H). 13C NMR: δ 159.3, 148.6, 138.2, 137.4, 129.1,
126.6, 126.0, 124.2, 74.0, 15.8. IR (CHCl3) νCO: 2068, 2030,
1993 cm-1. UV-vis (CHCl3): λmax 465.6 (ꢀ ) 3000 M-1 cm-1),
336 (ꢀ ) 9000 M-1 cm-1) nm. MS (EI): m/z 481 (M+), 453 (M+
- CO), 425 (M+ - 2CO), 397 (M+ - 3CO), 369 (M+ - 4CO),
341 (M+ - 5CO), 313 (M+ - 6CO), 201 (L+). Anal. Calcd for
Fe2C18H11NSO6: C, 44.91; H, 2.28; N, 2.91. Found: C, 45.01;
H, 2.31; N, 2.89. Compound 3a : 1H NMR δ 7.65 (d, J ) 5.1
Hz, 1H), 7.45 (d, J ) 5.1 Hz, 1H), 7.27 (m, 3H), 7.11 (m, 3H),
6.90 (dd, 2H), 6.83 (dd, 1H), 6.63 (d, J ) 3.9 Hz, 1H), 6.49 (dd,
1H), 6.04 (d, 2H), 5.05 (d, J ) 6.2 Hz, 1H), 4.46 (d, J ) 5.7 Hz,
1H), 4.38 (dd, 1H). 13C NMR: δ 159.4, 157.9, 146.9, 144.9,
138.6, 135.2, 129.9, 129.4, 129.0, 128.3, 127.3, 126.4, 125.5,
117.9, 113.6, 86.8, 63.2. IR (CHCl3): νCO 2067, 2026, 1996,
1960 cm-1; νNH 3403 cm-1. UV-vis (CHCl3): λmax 443.6 (ꢀ )
2500 M-1 cm-1), 343.2 (ꢀ ) 8800 M-1 cm-1) nm. MS (EI): m/z
602 (M+ - CO), 574 (M+ - 2CO), 546 (M+ - 3CO), 518 (M+
-
4CO), 490 (M+ - 5CO), 189 (4a +). Compound 5b: 1H NMR δ
7.37 (1H), 7.24 (1H), 7.12 (2H), 6.71 (2H), 6.63 (1H), 6.08 (1H),
4.64 (2H), 2.60 (3H). IR (CHCl3): νCO 2068, 2028, 1996, 1981,
1732 cm-1; νNH 3416 cm-1. MS (EI): m/z 658 (M+), 630 (M+
-
CO), 602 (M+ - 2CO), 546 (M+ - 4CO), 518 (M+ - 5CO), 203
(4b+).
Ack n ow led gm en t. Financial support from the Na-
tional Science Council (Taiwan, ROC) is gratefully
acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Text of the X-ray
crystal structure experimental details, tables of the experi-
mental details, atomic coordinates, anisotropic dispalcement
parameters, and bond distances and angles, and ORTEP
diagrams of 2b and 3a (33 pages). Ordering information is
given on any current masthead page.
655 (M+ + 1), 626 (M+ - CO), 598 (M+ - 2CO), 570 (M+
-
3CO), 542 (M+ - 4CO), 514 (M+ - 5CO), 486 (M+ - 6CO),
466 (M+ - L′), 188 (L′+), 186 (L+). Anal. Calcd for Fe2C28H18
-
N2S2O6: C, 51.38; H, 2.75; N, 4.28; O, 14.68. Found: C, 51.63;
H, 2.78; N, 4.26; O, 14.78. Compound 3b: 1H NMR δ 7.23
OM961092X