Synthesis and reactivity of fac-[Fe(CO)3(SR)3]- (R = C7H4SN, C4H3S, C4H2O-o-CH3) and heterotrimetallic Fe(II)-Ni(II)-Fe(II)-thiolate complex

Article abstract of DOI:10.1016/S0020-1693(01)00553-9

The reaction of 2 equiv. of diorganyl disulfides, (bis(2-benzothiazolyl) disulfide, di(2-thienyl) disulfide, and bis(2-methyl-3-furyl) disulfide), with 1 equiv. of [HFe(CO)₄]^- affords the stable, tridentate fac-[Fe(CO)₃(SR

Full text of DOI:10.1016/S0020-1693(01)00553-9

www.elsevier.nl/locate/ica
Inorganica Chimica Acta 322 (2001) 99–105
Synthesis and reactivity of fac-[Fe(CO)3(SR)3]− (R=C7H4SN,
C4H3S, C4H2O-o-CH3) and heterotrimetallic
Fe(II)–Ni(II)–Fe(II)–thiolate complex
Wen-Feng Liaw a,*, Jiun-Hung Lee a, Hung-Bin Gau a, Chien-Hong Chen a,
Gene-Hsiang Lee b
a Department of Chemistry, National Changhua Uni6ersity of Education, Changhua 50058, Taiwan, ROC
b Instrumentation Center, National Taiwan Uni6ersity, Taipei 10764, Taiwan, ROC
Received 1 March 2001; accepted 9 July 2001
Abstract
The reaction of 2 equiv. of diorganyl disulfides, (bis(2-benzothiazolyl) disulfide, di(2-thienyl) disulfide, and bis(2-methyl-3-furyl)
disulfide), with 1 equiv. of [HFe(CO)4]− affords the stable, tridentate fac-[Fe(CO)3(SR)3]− (R=C7H4SN (1); C4H3S (2);
C4H2O-o-CH3 (3)) via the formation of intermediate [RSFe(CO)4]−, respectively. In contrast, oxidative addition of 2-aminophenyl
disulfide to [Fe(CO)4(ꢀSC6H4-o-NH2)]−, obtained from reaction of [HFe(CO)4]− and 2-aminophenyl disulfide, and concomitant
displacement of [SC6H4-o-NH2]− leads to the neutral monomeric compound cis-[Fe(CO)2(ꢀSC6H4-o-NH2)2] (6). Obviously, the
reactivity and stability of the iron–thiolate derivatives may be tailored by pendant ligand selection, and the reaction pathway is
tailored according to the bond strength inherent in the organodisulfides and to the nucleophilicity of thiolate atoms in
[RSFe(CO)4]− complexes. In particular, compounds fac-[Fe(CO)3(SR)3]− serve as chelating metalloligand and intermetal thiolate
ligand-transfer reagent to synthesize the linear heterotrinuclear [(CO)3Fe(m-SR)3Ni(m-SR)3Fe(CO)3] (4) (R=C4H2O-o-CH3) and
the neutral [Fe(CO)2(SC4H3S)2(bipy)] (5) (bipy=bipyridine). © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Iron–thiolate; Iron–nickel–thiolate; Thiolate ligand-transfer; Metallochelating
fac-[Fe(CO)3(ER)3]− complexes which are useful in the
syntheses of [(CO)3Fe(m-SePh)3M(m-SePh)3Fe(CO)3]
(M=Ni, Zn, Cd, Fe) with homoleptic hexaseleno-
1. Introduction
The recent report of active-site structure of [Fe] and
[NiFe] hydrogenases has highlighted the chemistry of
dinuclear iron–thiolate cyanocarbonyl and hetero-
bimetallic iron–nickel–thiolate cyanocarbonyl com-
latometal core [10], [(CO)3Mn(m-2-SC4H3S)3Ni(m-
SePh)3Fe(CO)3]− with heteroleptic hexachalcogenolato-
nickel core NiS3Se3 [11], and distorted square planar
[Ni(CO)(SePh)3]−, the biomimetic nickel-site structure
pounds individually [1–7]. The synthesis of
of CO dehydrogenases and [NiFeSe] hydrogenases [12].
iron(II)–terminal thiolate compounds and hetero-
However, we have been unable to observe any indica-
bimetallic nickel–iron–thiolate complexes presents
tions of formation of fac-[Fe(CO)3(SPh)3]− complex in
challenges, particularly in the area of thiolate-bridged
the reaction of [HFe(CO)4]− and (PhS)2 under the same
dinuclear systems where ideal precursors are apt to exist
reaction condition [10b]. The attempted synthesis of
fac-[Fe(CO)3(SPh)3]− and the stable fac-[Fe(CO)3-
(SR)3]− in a manner analogous to fac-[Fe(CO)3-
(EPh)3]− (E=Te, Se) by reaction of 1 equiv. of
[HFe(CO)4]− and 2 equiv. of (PhS)2/(RS)2 affords only
[PhSFe(CO)4]− and the thermally extremely unstable
fac-[Fe(CO)3(SR)3]− (SR=4-nitrophenyl thiolate,
2,4,5-trichlorophenyl thiolate), respectively [10b].
as stable polynuclear compounds [8,9]. Recent work in
this laboratory has shown that the anionic iron-hydride
carbonyl [HFe(CO)4]− activates the E–E bond of dior-
ganyl dichalcogenides (RE–ER, E=Te, Se) to yield
* Corresponding author. Fax: +886-4-721 1190.
E-mail address: chfeng@cc.ncue.edu.tw (W.-F. Liaw).
0020-1693/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0020-1693(01)00553-9

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W.-F. Liaw et al. / Inorganica Chimica Acta 322 (2001) 99–105
In our continued work on the synthesis of homodinu-
N2 atmosphere at 50 °C. However, upon being stirred
for extended periods in THF at 30 °C, the solution of
complexes 2 and 3 converted into an insoluble solid.
Subsequent reaction of complex 3 with Ni(ClO4)2
produced the neutral heterotrimetallic (CO)3Fe(m-
SR)3Ni(m-SR)3Fe(CO)3 (4) complex (R=C4H2O-o-
CH3), as a thermally stable, dark brown solid (Scheme
1c). Complex 4 is soluble in THF and CH2Cl2, spar-
ingly soluble in common organic solvents like acetoni-
clear iron–thiolate and heterodinuclear iron–nickel–
thiolate complexes [7,8], the potential biomimetic
active-site structural models of [Fe] and [NiFe] hydro-
genases individually, we have concentrated our atten-
tion on the development of the stable fac-[Fe(CO)3-
(SR)3]− and a synthetic route to iron–nickel–thiolate
compounds employing fac-[Fe(CO)3(SR)3]− as a chelat-
ing ligand and intermetal ligand-transfer reagent. Obvi-
ously, the reactivity and stability of iron thiolate
derivatives may be tailored by pendant ligand selection.
One aspect of the reactivity of [RSFe(CO)4]− toward
organodisulfides can be mentioned: the reaction path-
way is tailored according to the bond strength inherent
in the organodisulfides and to the nucleophilicity of
thiolate atoms in [RSFe(CO)4]− complexes.
1
trile and hexane. The IR carbonyl stretching and H
NMR spectra are consistent with the presence of the
hexacoordination of d8 Ni(II) and the octahedral, low-
spin d6 Fe(II) with facial tricarbonyls. It is notable that
fac-[Fe(CO)3(SR)3]− can serve as an effective metallo
chelating ligand for stabilizing the hexacoordinate d8
nickel(II) core [10c].
As shown in Scheme 1d, addition of 2 equiv. of
complex 2 to a mixture of Fe(ClO4)2·6H2O and 3 equiv.
of bipyridine in a mixed solvent CH3CN–THF under
nitrogen atmosphere at ambient temperature, finally led
to the dark red–brown cis-Fe(CO)2(SC4H3S)2(bipy) (5)
complex (bipy=bipyridine). Complex 5 is a stable,
diamagnetic species soluble in organic solvents. Its IR
spectrum shows two strong CO stretching bands, sup-
2. Results and discussion
The chemistry reported herein is summarized in
Scheme 1. Reaction of 2 equiv. of diorganyl disulfides
(RS)2 (R=C7H4SN, C4H3S, C4H2O-o-CH3) and 1
equiv. of coordinatively unsaturated, low-valent, an-
ionic [PPN][HFe(CO)4] (or [Et4N][HFe(CO)4]) proceeds
readily with evolution of gaseous CO in THF at room
temperature. IR measurements of wCO (C36) showed the
formation of fac-[Fe(CO)3(SR)3]− (R=C7H4SN (1);
C4H3S (2); C4H2O-o-CH3 (3)) via the formation of
intermediate [RSFe(CO)4]− (Scheme 1a and b) [10a].
The iron(II)–thiolate derivatives 1–3 appear to be sta-
ble to air, and are soluble in most polar organic sol-
vents, such as THF and CH2Cl2. Surprisingly, complex
1 is stable either as a solid or in organic solution under
1
porting a cis position of two CO ligands [13]. The H
and 13C NMR spectra show the expected signals for the
[SꢀC4H3S]− ligands in a diamagnetic d6 Fe(II) species.
The formation of complex 5 indicates the thiolate and
CO ligand-transfer from one iron(II) center to another.
This redistribution reaction suggests that complexes
1–3 may be employed as an intermetal thiolate-transfer
reagent.
In contrast, reaction of 1 equiv. of [HFe(CO)4]− and
2 equiv. of 2-aminophenyl disulfide in THF finally led
to the formation of the known neutral cis-
Fe(CO)2(ꢀSC6H4-o-NH2)2 (6) identified by IR, and X-
ray diffraction, and the insoluble [PPN][SC6H4-o-NH2]
(Scheme 1e and f) [14]. The anionic [SC6H4-o-NH2]−
ligands in complex 6 bind to the Fe(II) atom in a
bidentate manner, forming two five-membered chelate
rings. As illustrated in Scheme 1e and f, the proposed
mechanism involves cleavage of sulfur–sulfur bond to
yield the monodentate (S-bonded) [Fe0(CO)4(ꢀSC6H4-o-
NH2)]− with the liberation of HꢀSC6H4-o-NH2, and
the subsequent oxidative addition of 2-aminophenyl
disulfide to the anionic [Fe(CO)4(ꢀSC6H4-o-NH2)]−
yielding the intermediate fac-[Fe(CO)3(ꢀSC6H4-o-
NH2)3]− (Scheme 1e). Subsequent elimination of
[SC6H4-o-NH2]−, concomitant dissociation of CO and
coordination of nitrogen atom of the bidentate
[ꢀSC6H4-o-NH2ꢀ]− ligands to the Fe(II) result in the
formation of the neutral complex 6 (Scheme 1f). Com-
plex 6 is soluble and stable in THF–hexane solution.
The IR spectrum of complex 6 showing two strong CO
stretching bands supports a cis orientation of two CO
ligands.
Scheme 1.

W.-F. Liaw et al. / Inorganica Chimica Acta 322 (2001) 99–105
101
average). The anionic complex 2 is isostructural with
the anionic complex 1. Fig. 2 displays a thermal ellip-
soid plot of the anionic complex 2 and selected dis-
tances and angles are given in Table 1. The S···S
contact distances in 1 and 2 are in the range 2.991–
,
3.172 and 2.929–3.038 A, respectively, indicative of the
absence of direct SꢀS bonding.
The X-ray structural analysis of complex 4, shown in
Fig. 3, reveals a linear chain of one nickel(II) and two
iron(II) atoms. The centrosymmetric trinuclear iron–
nickel–iron thiolate complex 4 appears to have no
precedent in iron–nickel–thiolate chemistry [15]. The
central Ni(II) is in a distorted octahedral arrangement
with the sulfur atoms of thiolates in two parallel faces
of the octahedron capped by tricarbonyl iron(II) frag-
Fig. 1. ORTEP drawing and labeling scheme of fac-
[Fe(CO)3(SC7H4SN)3]− with thermal ellipsoids drawn at the 50%
probability level.
Table 1
,
Selected bond distances (A) and bond angles (°) for complexes 1 and
2
Complex 1
Bond distances
Fe(1)ꢀS(1)
Fe(1)ꢀS(1B)
Fe(1)ꢀC(1A)
2.337(3)
2.337(6)
1.825(8)
Fe(1)ꢀS(1A)
Fe(1)ꢀC(1)
Fe(1)ꢀC(1B)
2.337(3)
1.825(8)
1.825(8)
Bond angles
C(1A)ꢀFe(1)ꢀC(1)
C(1)ꢀFe(1)ꢀS(1B)
C(1B)ꢀFe(1)ꢀS(1)
93.2(4)
96.9(3)
85.0(3)
C(1)ꢀFe(1)ꢀC(1B)
C(1A)ꢀFe(1)ꢀS(1A) 169.8(3)
S(1A)ꢀFe(1)ꢀS(1) 85.29(11)
93.2(4)
S(1B)ꢀFe(1)ꢀS(1A) 85.29(11) S(1B)ꢀFe(1)ꢀS(1)
85.28(11)
Complex 2
Bond distances
FeꢀC(1)
FeꢀC(3)
FeꢀS(3)
Fig. 2. ORTEP drawing and labeling scheme of fac-
[Fe(CO)3(SC4H3S)3]− with thermal ellipsoids drawn at the 30% prob-
ability level.
1.784(6)
1.791(5)
2.338(1)
FeꢀC(2)
FeꢀS(1)
FeꢀS(5)
1.778(6)
2.348(1)
2.365(2)
Bond angles
C(1)ꢀFeꢀC(2)
C(1)ꢀFeꢀS(3)
C(3)ꢀFeꢀS(1)
C(3)ꢀFeꢀS(5)
S(1)ꢀFeꢀS(3)
94.7(2)
87.1(2)
85.1(2)
92.3(2)
83.82(5)
C(1)ꢀFeꢀC(3)
C(2)ꢀFeꢀS(1)
C(2)ꢀFeꢀS(5)
S(1)ꢀFeꢀS(5)
S(3)ꢀFeꢀS(5)
95.0(2)
171.3(2)
85.7(2)
85.65(5)
85.48(6)
The structure of the fac-[Fe(CO)3(SꢀSNC7H4)3]−
unit in Et4N+ salt is shown in Fig. 1. Selected bond
distances and angles are collected in Table 1. The X-ray
crystal structure of complex 1 consists of two crystallo-
graphically independent molecules. As expected, the
geometry around Fe is a distorted octahedral with bond
angles 85.29(11)° for S(1B)ꢀFe(1)ꢀS(1A), 93.2(4)° for
C(1A)ꢀFe(1)ꢀC(1), and 85.0(3)° for C(1)ꢀFe(1)ꢀS(1A)
confirming the spectral assignment of a fac-configura-
,
tion. The mean Fe(II)ꢀS bond of length 2.337(3) A
(average) in complex 1 is slightly shorter than the
terminal Fe(II)ꢀS distances in complex 2 (2.350(2) A
Fig. 3. ORTEP drawing and labeling scheme of (CO)3Fe(SC4H2O-o-
CH3)3Ni(SC4H2O-o-CH3)3Fe(CO)3 with thermal ellipsoids drawn at
the 30% probability level.
,

102
W.-F. Liaw et al. / Inorganica Chimica Acta 322 (2001) 99–105
Table 2
Fig. 4 displays a thermal ellipsoid plot of the neutral
complex 5 and selected distances and angles are col-
lected in Table 2. The constraints of the bipyridine
ligand generates an angle of 81.21(24)° N(1)ꢀFeꢀN(2),
enforcing a distortion from an octahedra at the six-co-
,
Selected bond distances (A) and bond angles (°) for complexes 4 and
5
Complex 4
Bond distances
Ni(1)ꢀS(1)
Fe(1)ꢀS(1)
2.413(1)
2.342(1)
Ni(1)ꢀS(1A)
Fe(1)ꢀS(1B)
2.413(1)
2.342(1)
,
ordinate iron site. The Fe(II)ꢀS distances (2.334(2) A
average) are comparable with the terminal Fe(II)ꢀS
,
distances of 2.337(3) and 2.350(2) A in complexes 1 and
Bond angles
S(1)ꢀNi(1)ꢀS(1A) 180.0
S(1B)ꢀNi(1)ꢀS(1)
C(1B)ꢀFe(1)ꢀS(1)
S(1A)ꢀNi(1)ꢀS(1C)
80.11(4)
96.3(2)
169.3(2)
2 individually.
In summary, the stable fac-[Fe(CO)3(SR)3]− com-
plexes have been prepared by reaction of [HFe(CO)4]−
and diorganyl disulfide (bis(2-benzothiazolyl) disulfide,
di(2-thienyl) disulfide, and bis(2-methyl-3-furyl)
disulfide) under mild conditions. It is notable that
fac-[Fe(CO)3(SR)3]− can serve as an effective tridentate
metallo ligand for stabilizing the hexacoordinate d8
Ni(II) core of the heterotrimetallic iron(II)–nickel(II)–
iron(II) thiolate complex 4, and can also be employed
as an intermetal thiolate ligand-transfer reagent to syn-
thesize complex 5. Also, the reaction of 2-aminophenyl
disulfide with [HFe(CO)4]− affords the neutral
monomeric compound 6, cis-Fe(CO)2(ꢀSC6H4-o-
NH2ꢀ)2, the result is consistent with the S, NH2-chelat-
ing [ꢀSC6H4-o-NH2ꢀ] ligand enhancing the stability of
iron in the higher oxidation state (Fe(II) state). The
reactivity and stability of iron thiolate derivatives may
be tailored by pendant ligand selection, and the reac-
tion pathway is tailored according to the bond strength
inherent in the organodisulfides and to the nucleophilic-
ity of thiolate atoms in [RSFe(CO)4]− complexes.
99.89(4) C(1)ꢀFe(1)ꢀC(1B)
93.73(14) C(1)ꢀFe(1)ꢀS(1B)
Complex 5
Bond distances
FeꢀS(1)
FeꢀN(1)
FeꢀC(1)
2.343(2)
1.973(4)
1.763(5)
FeꢀS(3)
FeꢀN(2)
FeꢀC(2)
2.327(2)
1.974(5)
1.789(8)
Bond angles
S(1)ꢀFeꢀS(3)
S(1)ꢀFeꢀN(2)
S(1)ꢀFeꢀC(2)
S(3)ꢀFeꢀN(2)
N(1)ꢀFeꢀN(2)
170.78(6) S(1)ꢀFeꢀN(1)
91.31(14) S(1)ꢀFeꢀC(1)
88.4(3)
90.99(14) S(3)ꢀFeꢀC(1)
81.7(3) N(1)ꢀFeꢀC(1)
87.45(13)
91.6(2)
84.05(13)
97.03(19)
177.1(4)
S(3)ꢀFeꢀN(1)
3. Experimental
Manipulations, reactions, and transfers of samples
were conducted under nitrogen according to standard
Schlenk techniques or in a glove-box (argon gas). Sol-
vents were distilled under nitrogen from appropriate
drying agents (diethyl ether from CaH2; acetonitrile
from CaH2–P2O5; methylene chloride from P2O5; hex-
ane and tetrahydrofuran (THF) from sodium–ben-
zophenone) and stored in dried, N2-filled flasks over 4
Fig. 4.
ORTEP
drawing and labeling scheme of cis-
Fe(CO)2(SC4H3S)2(bipy) (bipy=bipyridine) with thermal ellipsoids
drawn at the 30% probability level.
ments. The arrangement of the thiolate substituents is
symmetrical so that the Fe–Ni–Fe vector lies on a
threefold rotation axis, and the staggered conformation
of two parallel triangular thiolate faces promises the
best minimization of interactions between the thiolates.
The average Fe(II)ꢀS distance of 2.342(1) A is close to
the value of 2.337(3) and 2.350(2) A in complexes 1 and
,
A molecular sieves. A nitrogen purge was used on these
solvents before use and transfers to reaction vessels
were via stainless-steel cannula under N2 at a positive
pressure. The reagents 2-aminophenyl disulfide, bis(2-
benzothiazolyl) disulfide, di(2-thienyl) disulfide, and
bis(2-methyl-3-furyl) disulfide, bis(triphenylphospho-
ranylidene)ammonium chloride (Lancaster/Aldrich)
were used as received. IR spectra were recorded in a
spectrometer (Bio-Rad FTS-185) with sealed solution
cells (0.1 mm) and KBr windows. NMR spectra in a
Bruker AC 200 spectrometer, 1H and 13C chemical
shifts being relative to tetramethylsilane and UV–Vis
spectra in a GBC 918 spectrophotometer. Analyses of
carbon, hydrogen and nitrogen were obtained with a
CHN analyzer (Heraeus).
,
,
2 individually. The average Ni(II)ꢀS bond length of
2.413(1) A in complex 4 is significantly longer than the
,
terminal Ni(II)ꢀS distances in distorted tetrahedral
[Ni(SPh)4]2− (average 2.281(1) A) (Table 2) [16]. Also,
,
,
the Fe···Ni distances, average 3.121 A, exclude any
direct metal–metal interaction. Obviously, the structure
is best described as two tridentate fac-[Fe(CO)3-
(SC4H2O-o-CH3)3]− ligands coordinated to Ni(II).

W.-F. Liaw et al. / Inorganica Chimica Acta 322 (2001) 99–105
103
1
3.1. Preparation of fac-[Et4N][Fe(CO)3(SC7H4SN)3] (1)
(fac-[PPN][Fe(CO)3(SC4H3S)3] (2),
fac-[PPN][Fe(CO)3(SC4H2O-o-CH3)3] (3))
(vs). H NMR (CD2Cl2, l ppm): 33.19 (br), 4.11 (br),
0.34 (br) (SC4H2O-o-CH3). Absorption spectrum: umax
(nm) (m,
M
−1 cm−1
)
(THF): 390 (23 376), 477
(234 751). Anal. Found: C, 42.89; H, 2.88. Calc. for
The compound [PPN][HFe(CO)4] (0.2 mmol, 0.142 g)
or [Et4N][HFe(CO)4] (0.2 mmol, 0.06 g) [17] was loaded
into a 50-ml Schlenk flask with 0.133 g (0.4 mmol) of
bis(2-benzothiazolyl) disulfide (0.092 g (0.4 mmol) of
di(2-thienyl) disulfide; 76 ml (0.4 mmol) of bis(2-methyl-
3-furyl) disulfide), and 5 ml of THF was added. The
reaction mixture was stirred at ambient temperature for
20 min, after which 10 ml of hexane was added. The
reaction mixture was filtered, and the orange solid was
dried under vacuum to afford the pure product in
quantitative yield (0.070 g, 46% for 1; 0.111 g, 53% for
2). X-ray quality crystals were obtained by diffusion of
hexane into a THF solution of complexes 1 and 2
individually at −15 °C for 4 weeks. Complex 1: IR
C36H30O12Fe2S6Ni: C, 42.50; H, 2.97%.
3.3. Preparation of cis-[Fe(CO)2(SC4H3S)2(bipy)]
(bipy=bipyridine) (5)
A solution containing fac-[PPN][Fe(CO)3(SC4H3S)3]
(0.410 g, 0.4 mmol) in CH3CN (5 ml) was added to a
mixture of bipyridine (0.094 g, 0.6 mmol) and
Fe(NO3)2·6H2O
(0.073
g,
0.2
mmol)
(or
Fe(ClO4)2·6H2O) in THF (5 ml). After stirring
overnight at room temperature (r.t.) the solvent was
removed under reduced pressure. The residue was dis-
solved in THF (10 ml) under N2, and the dark red–
brown solution filtered to remove [PPN][ClO4]. The
filtrate (THF) was concentrated under vacuum and
then hexane was slowly added to precipitate a dark
brown solid (yield 78%). The crystals, suitable for X-
ray crystallography, were recrystallized by vapor diffu-
sion of hexane into a concentrated THF solution of
complex 5 at −15 °C. IR (THF, cm−1): w(CO) 2024
1
(THF, cm−1): w(CO) 2083 (vs) 2035 (s, br). H NMR
(C4D8O, l ppm): 6.97 (t), 7.12 (t) (C7H4SN). Absorp-
tion spectrum: umax (nm) (m, M−1 cm−1) (THF): 393
(2352), 383 (2392). Anal. Found: C, 61.77; H, 4.24; N,
4.40. Calc. for C32H32O3N4S6Fe: C, 61.21; H, 4.08; N,
4.76%. Complex 2: IR (THF, cm−1): w(CO) 2053 (vs),
1
1
1994 (s, br). H NMR (C4D8O, l ppm): 7.04 (d), 6.83
(s), 1979 (s). H NMR (C4D8O, l ppm): 9.15 (d), 8.18
(d), 6.65 (t) (SꢀC4H3S). 13C NMR (C4D8O, l ppm):
209.47 (CO). Absorption spectrum: umax (nm) (m,
(d), 7.97 (t), 7.52 (t), 6.78 (d), 6.41 (t), 6.05 (d)
(SC4H3S). 13C NMR (C4D8O, l ppm): 153.82, 138.32,
133.69, 127.38, 127.24, 126.56, 123.41 (SC4H3S, phen).
Absorption spectrum: umax (nm) (m, M−1 cm−1) (THF):
322 (22 711). Anal. Found: C, 48.19; H, 2.83; N, 5.62.
Calc. for C20H14O2N2S4Fe: C, 48.13; H, 3.00; N, 5.48%.
M
−1 cm−1) (THF): 467 (1250), 340 (9378). Anal.
Found: C, 59.74; H, 3.94; N, 1.30. Calc. for
C51H39O3P2S6NFe: C, 59.82; H, 3.84; N, 1.37%. Com-
plex 3 (isolated as the dark brown oily product): IR
(CH3CN, cm−1): w(CO) 2049 (vs), 1987 (s, br). 1H
NMR (C4D8O, l ppm): 2.31 (s), 6.34 (br), 6.97 (br)
(SC4H2O-o-CH3).
3.4. Preparation of cis-[Fe(CO)2(ꢀSC6H4-o-NH2ꢀ)2] (6)
Caution: Perchlorate salts of metal complexes with
organic ligands are potentially explosive; only small
amounts of material should be prepared and handled
with great caution.
[PPN][HFe(CO)4] (0.2 mmol, 0.142 g) [17] was added
to 2-aminophenyl disulfide (0.4 mmol, 0.100 g) in THF
(8 ml) at ambient temperature. After 12 h of stirring at
r.t., hexane (8 ml) was added into the solution. The
red–brown solution was then filtered to remove
[PPN][SC6H4-o-NH2]. The filtrate was stored at −
15 °C for 4 weeks to induce precipitation of dark red
brown crystals of the known cis-[Fe(CO)2(ꢀSC6H4-o-
NH2ꢀ)2], identified by IR, and X-ray crystallography
[14]. IR (THF, cm−1): w(CO) 2027 (s), 1971 (s). Anal.
Found: C, 47.10; H, 2.31; N, 7.99. Calc. for
C14H12O2N2S2Fe: C, 47.21; H, 2.26; N, 7.86%.
3.2. Preparation of [(CO)3Fe(SC4H2O-o-CH3)3Ni-
(SC4H2O-o-CH3)3Fe(CO)3] (4)
A solution containing [PPN][HFe(CO)4] (1 mmol,
0.71 g), bis(2-methyl-3-furyl) disulfide (2 mmol, 0.378
ml), and Ni(ClO4)2·6H2O (0.5 mmol, 0.146 g) in aceto-
nitrile (10 ml) was stirred under nitrogen atmosphere at
ambient temperature for 1 h. A brown solution accom-
panied by a dark brown solid was formed. The mother-
liquor was removed under a positive pressure of N2 and
the dark brown solid was washed twice with CH3CN.
Tetrahydrofuran was added to extract the product, and
then hexane was slowly added to precipitate a dark
brown solid (yield 0.330 g, 64%). The crystals, suitable
for X-ray crystallography, were recrystallized by vapor
diffusion of hexane into a concentrated THF solution
at −15 °C. IR (THF, cm−1): w(CO) 2076 (vs), 2023
4. Crystallography
Crystallographic data of complexes 1, 2, 4 and 5 are
summarized in Tables 3 and 4, and as supporting
information (see Section 5). The crystals of 1, 2, 4 and
5 are chunky. The crystals of 1, 2, 4, 5 chosen for X-ray
diffraction studies measured 0.36×0.24×0.20 mm,
0.30×0.25×0.05 mm, 0.15×0.15×0.10 mm, and

104
W.-F. Liaw et al. / Inorganica Chimica Acta 322 (2001) 99–105
Table 3
atoms and fixed hydrogen atoms contribution was
based on F2. Diffraction measurements were carried
out in a Nonius CAD4 diffractometer with graphite-
monochromated Mo Ka radiation [18]. A € scan ab-
sorption correction was made. The SHELXTL package of
programs was employed for structure solution and
refinement [19]. In complex 5 (Fig. 4), the positions of
S(4) and C(8) atoms are disordered (50%). Diffraction
measurements for complexes 1, 2 and 4 were carried
out in a Siemens SMART CCD diffractometer with
graphite-monochromated Mo Ka radiation (u 0.7107
Crystallographic data and structure refinements parameters for com-
plexes 1 and 2
1
C
2
Empirical formula
Formula weight
Crystal system
Temperature (K)
Space group
32H32O3N4S6Fe
C51H39NO3P2S6Fe
1023.98
monoclinic
295(2)
P21
0.7107
768.83
trigonal
150(1)
P31c
,
u (A) (Mo Ka)
0.7107
Unit cell dimensions
,
a (A)
12.9022(1)
12.9022(1)
24.9774(5)
90
90
120
3600.85(8)
4
1.418
9.7591(2)
26.0605(4)
9.8472(2)
90
97.187(1)
90
2484.73(8)
2
1.369
,
b (A)
,
A) and q between 1.63 and 26.37° for complex 1,
,
c (A)
between 1.56 and 26.37° for complex 2, and between
2.22 and 27.50° for complex 4. Least-squares refinement
of the positional and anisotropic thermal parameters
for all non-hydrogen atoms and fixed hydrogen atoms
contribution was based on F2. A SADABS [20] absorp-
tion correction was made. The SHELXTL [19] structure
refinement program was employed. In complex 2 (Fig.
2), the positions of S(2) and C(5) atoms are disordered
(50%).
h (°)
i (°)
k (°)
3
,
V (A )
Z
Dcalc (g cm−3
)
v (cm−1
)
8.05
6.62
a
R
0.0994
0.2760
1.053
0.0451
0.0881
0.948
b
RWF
2
Goodness-of-fit on F2
a R=ꢀ(ꢁFoꢁ−ꢁFcꢁ)/ꢀꢁFoꢁ.
b RWF ={ꢀ[w(Fo2−Fc2)2]/ꢀ[w(Fo2)2]}1/2
.
2
5. Supplementary material
Table 4
Tables of crystal data and experimental conditions
for the X-ray studies, atomic coordinates and Beq val-
ues, complete listings of bond lengths and bond angles,
and anisotropic temperature factors for fac-[Et4N]-
[Fe(CO)3(SꢀC7H4SN)3], fac-[PPN][Fe(CO)3(SꢀC4H3S)3],
(CO)3Fe(SC4H2O-o-CH3)3Ni(SC4H2O-o-CH3)3Fe(CO)3,
and cis-[Fe(CO)2(SC4H3S)2(bipy)]. This material is
available free of charge at the CSD.
Crystallographic data and structure refinements parameters for com-
plexes 4 and 5
4
5
Empirical formula
Formula weight
Crystal system
Temperature (K)
Space group
C36H30O12NiS6Fe2
1017.37
rhombohedral
150(1)
R3
0.7107
C20H14O2N2S4Fe
498.43
monoclinic
295(2)
P21
0.7107
,
u (A) (Mo Ka)
Unit cell dimensions
,
a (A)
18.0122(4)
18.0122(4)
11.3103(4)
90
90
120
3177.9(2)
3
1.595
10.747(3)
10.573(3)
10.837(3)
90
119.21(2)
90
1074.8(5)
2
1.540
Acknowledgements
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
We thank the National Science Council (Taiwan) for
support of this work.
3
,
Z
Dcalc (g cm−3
)
References
v (cm−1
)
14.69
11.09
a
R
0.0577
0.1538
1.038
0.0447
0.1194
1.076
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